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Effect of low-dose ionizing radiation on luminous marine bacteria: Radiation hormesis and toxicity
... Aquatic biota might be sensitive to the presence of humic substances (HS), products of oxidative decomposition of organic matter in water body sediments, and natural complexing and redox agents, which play an important role as natural toxicity attenuators [36][37][38][39][40]. Phenolic and other active groups in HS result in their capability of mitigating toxic impacts of oxidizers of both organic and inorganic types [30,41,42], similarly to other natural phenolic compounds [43,44]. The biological activity of HS is currently discussed intensively [6,[45][46][47][48][49][50]. ...
... their capability of mitigating toxic impacts of oxidizers of both organic and inorganic types [30,41,42], similarly to other natural phenolic compounds [43,44]. The biological activity of HS is currently discussed intensively [6,[45][46][47][48][49][50]. This review is aimed at considering the bioeffects of radionuclides of alpha and beta types, such as thorium-232, americium-241, and uranium-(235 + 238), tritium, as well as gamma-irradiation, under the conditions of low-intensity irradiation. ...
... The Gu group (National Environmental Biotechnology Research Laboratory, Kwangju, South Korea) was the first to apply bioluminescence to monitor the bioeffects of radiation (using gamma radiation as an example) [75]. In addition to the abovementioned groups, there are other studies which apply luminescent bacteria for monitoring the radiation bioeffects [6,72,[76][77][78]. Unicellular bacterial responses form the basis for understanding the nature of low-dose effects on multicellular organisms. ...
Radioactive contaminants create problems all over world, involving marine ecosystems, with their ecological importance increasing in the future. The review focuses on bioeffects of a series of alpha and beta emitting radioisotopes (americium-241, uranium-(235 + 238), thorium-232, and tritium) and gamma radiation. Low-intensity exposures are under special consideration. Great attention has been paid to luminous marine bacteria as representatives of marine microorganisms and a conventional bioassay system. This bioassay uses bacterial bioluminescence intensity as the main testing physiological parameter; currently, it is widely applied due to its simplicity and sensitivity. Dependences of the bacterial luminescence response on the exposure time and irradiation intensity were reviewed, and applicability of hormetic or threshold models was discussed. A number of aspects of molecular intracellular processes under exposure to low-intensity radiation were analyzed: (a) changes in the rates of enzymatic processes in bacteria with the bioluminescent system of coupled enzymatic reactions of NADH:FMN-oxidoreductase and bacterial luciferase taken as an example; (b) consumption of an intracellular reducer, NADH; (c) active role of reactive oxygen species; (d) repairing of the DNA damage. The results presented confirm the function of humic substances as natural radioprotectors.
... Previous studies [44][45][46][47][48] have demonstrated both the activation and inhibition effects of tritium on marine bacteria ( Figure 1A), as well as the absence of a monotonic dependence of the luminescence response on tritium concentration at chronic low-dose exposure (<0.03 Gy), in a wide range of tritium radioactivity from 0.0001 to 200 MBq·L −1 ( Figure 1B). Intact and lyophilized bacterial suspensions were studied and exhibited similar results. ...
... In addition, it was shown that tritium activated bacterial growth at the activity levels of 10-10 4 kBq·L −1 and suppressed this growth at higher activities (>10 5 kBq·L −1 ) [45]. An increase in the bacterial luminescence intensity in the presence of tritiated water, HTO, was demonstrated in a series of experiments where bi-phasic dependence (activation + inhibition) was found in [44,46], whereas mono-phasic dependence (activation only) was shown in [42,58,59]. ...
... In addition, it was shown that tritium activated bacterial growth at the activity levels of 10-10 4 kBq·L −1 and suppressed this growth at higher activities (>10 5 kBq·L −1 ) [45]. ...
Tritium is a byproduct of many radiochemical reactions in the nuclear industry, and its effects on aquatic organisms, particularly low-dose effects, deserve special attention. The low-dose effects of tritium on aquatic microbiota have been intensively studied using luminous marine bacteria as model microorganisms. Low-dose physiological activation has been demonstrated and explained by the signaling role of reactive oxygen species through the “bystander effect” in bacterial suspensions. The activation of microbial functions in natural reservoirs by low tritium concentrations can cause unpredictable changes in food chains and imbalances in the natural equilibrium. The incorporation of tritium from the free form into organically bound compounds mainly occurs in the dark and at a temperature of 25 °C. When tritium is ingested by marine animals, up to 56% of tritium is accumulated in the muscle tissue and up to 36% in the liver. About 50% of tritium in the liver is bound in non-exchangeable forms. Human ingestion of water and food products contaminated with background levels of tritium does not significantly contribute to the total dose load on the human body.
... (1) Marine bacteria [18][19][20][21] and their enzymes [22] have been used as bioassays for several decades; this is why the effects of exogenous compounds on these assay systems have been intensively studied. The effects of a series of radionuclides [23][24][25][26] and gamma radiation [27,28] on the bacteria and their enzymatic reactions were studied and compared. Thus, the predictive premise for the bioassays was formed based on the molecular mechanisms of the radiation-induced effects. ...
... These decay products are able to trigger electron/charge transfer in biochemical reactions and hence to affect the rates of cellular processes. Our previous studies [24,25] demonstrated both activation and inhibition effects of tritium on marine bacteria ( Figure 1A), as well as the absence of a monotonic dependence of a luminescence response vs. the tritium activity concentration at a chronic low-dose exposure (<0.03 Gy) in a wide range of tritium radioactivities: from 0.0001 to 200 MBq/L ( Figure 1B). This result was explained with the hormesis model involved in terms of the adaptation ability of the bacterial cells to the low-dose radiation. ...
... A prospect for evaluating the radiotoxic or radioprotective response can occur for luminous bacteria, systems of their coupled enzymatic reactions [16,25], as well as for individual enzymatic reactions. ...
The present study considers a possible role of enzymatic reactions in the adaptive response of cells to the beta-emitting radionuclide tritium under conditions of low-dose exposures. Effects of tritiated water (HTO) on the reactions of bacterial luciferase and NAD(P)H:FMN-oxidoreductase, as well as a coupled system of these two reactions, were studied at radioactivity concentrations ≤ 200 MBq/L. Additionally, one of the simplest enzymatic reactions, photobiochemical proton transfer in Coelenteramide-containing Fluorescent Protein (CLM-FP), was also investigated. We found that HTO increased the activity of NAD(P)H:FMN-oxidoreductase at the initial stage of its reaction (by up to 230%); however, a rise of luciferase activity was moderate (<20%). The CLM-FP samples did not show any increase in the rate of the photobiochemical proton transfer under the exposure to HTO. The responses of the enzyme systems were compared to the ‘hormetic’ response of luminous marine bacterial cells studied earlier. We conclude that (1) the oxidoreductase reaction contributes significantly to the activation of the coupled enzyme system and bacterial cells by tritium, and (2) an increase in the organization level of biological systems promotes the hormesis phenomenon.
... The presence of phenolic and other redox-active functional groups in HS accounts for their capability of reducing toxic impacts of organic and inorganic oxidizers [9-11], similar to the redox activity of other natural phenolic compounds [12,13]. The biological activity of HS is intensively discussed now [14][15][16][17][18][19]. ...
... The presence of phenolic and other redox-active functional groups in HS accounts for their capability of reducing toxic impacts of organic and inorganic oxidizers [9][10][11], similar to the redox activity of other natural phenolic compounds [12,13]. The biological activity of HS is intensively discussed now [14][15][16][17][18][19]. ...
... Our previous works revealed the peculiarities of the response of luminous marine bacteria to the low-dose radiation of alpha-, beta-, and gamma-types [15,[24][25][26][27][28][29][30][31]. Bacterial responses to alphaand beta-radionuclides corresponded to the conventional "hormesis" dose-response model [32][33][34][35]. ...
The paper studies the combined effects of beta-emitting radionuclide tritium and Humic Substances (HS) on the marine unicellular microorganism-luminous bacteria-under conditions of low-dose radiation exposures (<0.04 Gy). Tritium was used as a component of tritiated water. Bacterial luminescence intensity was considered as a tested physiological parameter. The bioluminescence response of the marine bacteria to tritium corresponded to the "hormesis" model: it included stages of bioluminescence inhibition and activation, as well as the absence of the effect. HS were shown to decrease the inhibition and activation effects of tritium, similar to those of americium-241, alpha-emitting radionuclide, studied earlier. Correlations between the bioluminescence intensity and the content of Reactive Oxygen Species (ROS) were found in the radioactive bacterial suspensions. The results demonstrate an important role of HS in natural processes in the regions of low radioactive contamination: HS can mitigate radiotoxic effects and adaptive response of microorganisms to low-dose radioactive exposures. The involvement of ROS in these processes was demonstrated.
... Luminous marine bacteria have been used as a toxicity bioassay for several decades (Bulich and Isenberg, 1981;Abbas et al., 2018); mechanisms of toxic effects in bacteria are intensively studied (Kudryasheva, 2006;Kudryasheva and Rozhko, 2015). The tested parameter here is luminescence intensity; it can be easily measured instrumentally with simple physical devices. ...
... Paper (Selivanova et al., 2013) considered an influence of tritiated water (0.0002-200 MBq/L) on the bacteria and their enzymatic reactions. Bioluminescent intensity, bacterial growth, cell damage, and tritium accumulation were under investigation (Selivanova et al., 2013;Kudryasheva and Rozhko, 2015). ...
... Detailed analysis of low-dose effect of tritium on luminescence of marine bacteria was conducted earlier (Selivanova et al., 2013;Kudryasheva and Rozhko, 2015). Luminescence was considered there as physiological parameter, along with bacterial growth (Alexandrova et al., 2010). ...
The paper continues study of exposures of luminous marine bacteria to low-dose radiation of tritium; tritiated water (HTO) was applied as a source of the irradiation. Hypothesis on involvement of Reactive Oxygen Species (ROS) to signaling mechanism of bacterial cells under exposure to low-intensity tritium radiation was verified. Bacterial bioluminescence intensity was considered as a tested physiological parameter; it was compared to the ROS production in the bacterial environment of different activity concentrations: 0.03, 4.0, and 500 MBq/L. Exposure of the bacteria to chronic low-dose tritium irradiation (<0.08 Gy) increased bioluminescence intensity and ROS production considerably (up to 300%). Spearman rank correlation coefficients were calculated and confirmed relations between the bioluminescence intensity and ROS production. Additional peculiarities of HTO effect were: independence of the bioluminescence intensity and ROS content on HTO activity concentration; low ROS content in bacteria-free aquatic environment. Effects of HTO on bacterial bioluminescence were attributed to: (1) trigger function of tritium decay products in the bacterial metabolic oxygen-dependent processes, with bioluminescence involved; (2) signaling role of ROS as intercellular messengers in "bystander effect"; (3) fixed amount of bacterial cells (3•107 cells/mL) provided the upper limits of the bioluminescence intensity and ROS content. As an outlook, in spite of low energy of tritium decay, its influence on aquatic biota via ROS production by microorganisms should be taken into consideration.
... The most well-known luminescent cellular bioassay is based on luminous marine bacteria; the main test parameter here is bioluminescence intensity. Bacterial bioluminescence is sensitive to toxic compounds; this is a reason why the marine bacterium has been used for several decades to assess environmental toxicity [13][14][15][16][17][18][19]. ...
... Luminous marine bacteria have been applied to monitor low-dose radiation effects for about a decade [19,21]. In this period, the effects of alpha-and beta-emitting radionuclides americium-241, uranium 235/338, and tritium, as well as those of gamma radiation, have been investigated [19,21,22,60,61,72]. ...
... Luminous marine bacteria have been applied to monitor low-dose radiation effects for about a decade [19,21]. In this period, the effects of alpha-and beta-emitting radionuclides americium-241, uranium 235/338, and tritium, as well as those of gamma radiation, have been investigated [19,21,22,60,61,72]. It was shown that the bacterial bioluminescence response to radionuclides americium-241 and tritium includes three stages: (1) threshold, (2) activation, and (3) inhibition. ...
The current paper reviews the applications of luminescence bioassays for monitoring the results of low-intensity exposures which produce a stimulative effect. The impacts of radioactivity of different types (alpha, beta, and gamma) and bioactive compounds (humic substances and fullerenols) are under consideration. Bioassays based on luminous marine bacteria, their enzymes, and fluorescent coelenteramide-containing proteins were used to compare the results of the low-intensity exposures at the cellular, biochemical, and physicochemical levels, respectively. High rates of luminescence response can provide (1) a proper number of experimental results under comparable conditions and, therefore, proper statistical processing, with this being highly important for “noisy” low-intensity exposures; and (2) non-genetic, i.e., biochemical and physicochemical mechanisms of cellular response for short-term exposures. The results of cellular exposures were discussed in terms of the hormesis concept, which implies low-dose stimulation and high-dose inhibition of physiological functions. Dependencies of the luminescence response on the exposure time or intensity (radionuclide concentration/gamma radiation dose rate, concentration of the bioactive compounds) were analyzed and compared for bioassays of different organization levels.
... Marine bacterium is a well-known luminescence cellular bioassay [8][9][10][11][12][13][14][15]. Intensity of the bacterial luminescence is highly sensitive to the presence of toxic compounds; therefore, marine bacterium has been widely used to assess environmental toxicity for almost 50 years [14,18,19], with radiation toxicity included during the last decade [20][21][22][23][24][25][26]. ...
... Previously, we investigated the effects of low doses of alpha, beta, and gamma radiation on the cellular bioassay system-luminous bacteria [20,[23][24][25][26]44]. The response of the cells to the low-dose alpha and beta radiation was complex; it included activation and inhibition stages, corresponding to a Bhormesis^toxicological model [20,[23][24][25][26]. Unlike alpha and beta radiation exposure, the low-intensity gamma radiation demonstrated only suppression of the luminescence function of the bacteria [44]. ...
... Previously, we investigated the effects of low doses of alpha, beta, and gamma radiation on the cellular bioassay system-luminous bacteria [20,[23][24][25][26]44]. The response of the cells to the low-dose alpha and beta radiation was complex; it included activation and inhibition stages, corresponding to a Bhormesis^toxicological model [20,[23][24][25][26]. Unlike alpha and beta radiation exposure, the low-intensity gamma radiation demonstrated only suppression of the luminescence function of the bacteria [44]. ...
The study suggests an application of a coelenteramide-containing fluorescent protein (CLM-CFP) as a simplest bioassay for gamma radiation exposures. “Discharged obelin,” a product of the bioluminescence reaction of the marine coelenterate Obelia longissima, was used as a representative of the CLM-CFP group. The bioassay is based on a simple enzymatic reaction—photochemical proton transfer in the coelenteramide-apoprotein complex. Components of this reaction differ in fluorescence color, providing, by this, an evaluation of the proton transfer efficiency in the photochemical process. This efficiency depends on the microenvironment of the coelenteramide within the protein complex, and, hence, can evaluate a destructive ability of gamma radiation. The CLM-CFP samples were exposed to gamma radiation (137Cs, 2 mGy/h) for 7 and 16 days at 20 °C and 5 °C, respectively. As a result, two fluorescence characteristics (overall fluorescence intensity and contributions of color components to the fluorescence spectra) were identified as bioassay parameters. Both parameters demonstrated high sensitivity of the CLM-CFP-based bioassay to the low-dose gamma radiation exposure (up to 100 mGy). Higher temperature (20 °C) enhanced the response of CLM-CFP to gamma radiation. This new bioassay can provide fluorescent multicolor assessment of protein destruction in cells and physiological liquids under exposure to low doses of gamma radiation. Open image in new window Graphical abstract ᅟ
... The simplicity of the registration procedure is beneficial because it enables researchers to conduct a large number of experiments under comparable conditions ensuring adequate statistical treatment of the results. Over recent decades, bioluminescent bacteria-based assays have been widely applied for toxicity monitoring in water media including the effects of low-dose radiation (Roda et al., 2009;Girotti et al., 2008;Kudryasheva and Tarasova, 2015;Kudryasheva and Rozhko, 2015). ...
... Radiosensitivity of organisms is usually evaluated as a doseeffect relationship, but there is a considerable uncertainty concerning low-dose exposures. Three models exist describing this relationship: linear, threshold, and hormesis models (Kudryasheva and Rozhko, 2015;Burlakova et al., 2004;Calabrese, 2014;Baldwin and Grantham, 2015). The hormesis hypothesis suggests that lowdose radiation can be favorable for living organisms. ...
... Probably, the hormesis model could be accepted as the basic one (Shi et al., 2016), while the other two (threshold and linear models) could be considered as simplified derivatives from the former coming into being under certain conditions. The review by Kudryasheva and Rozhko (2015) summarizes the effects of exposure of luminous marine bacteria to chronic lowintensive ionizing radiation of alpha and beta types. The effects of model solutions of americium-241, uranium-235þ238, and tritium were analyzed, nonlinear dose-response dependencies were demonstrated and attributed to the hormesis phenomenon. ...
Luminous marine bacteria are widely used in bioassays with luminescence intensity being a physiological parameter tested. The purpose of the study was to determine whether bacterial genetic alteration is responsible for bioluminescence kinetics change under low-dose radiation exposure. The alpha-emitting radionuclide ²⁴¹Am and beta-emitting radionuclide ³H were used as the sources of low-dose ionizing radiation. Changes of bioluminescence kinetics of Photobacterium phosphoreum in solutions of ²⁴¹Am(NO3)3, 7 kBq/L, and tritiated water, 100 MBq/L, were studied; bioluminescence kinetics stages (absence of effect, activation, and inhibition) were determined. Bacterial suspension was sampled at different stages of the bioluminescent kinetics; the doses accumulated by the samples were close or a little higher than a tentative limit of a low-dose interval: 0.10 and 0.85 Gy for ²⁴¹Am, or 0.11 and 0.18 Gy for ³H. Sequence analysis of the 16S ribosomal RNA gene did not reveal a mutagenic effect of low-dose alpha and beta radiation in the bacterial samples. Previous results on bacterial DNA exposed to low-dose gamma radiation (0.25 Gy) were analyzed and compared to those for alpha and beta irradiation. It is concluded that bioluminescence activation and/or inhibition under the applied conditions of low-dose alpha, beta and gamma radioactive exposure is not associated with DNA mutations in the gene sequences tested.
... Bacterial bioluminescent assay based on recombinant Escherichia coli has been previously used to test biological effects of highdose gamma-radiation exposures; doses accumulated by the bacteria were 2.6 Gy (Ptitsyn et al., 1997) and 1e200 Gy (Min et al., 2003). The last decade has seen the application of luminous bacteria to monitor biological effects of low-dose ionizing radiation (Kudryasheva and Rozhko, 2015). ...
... Radiosensitivity of living organisms is usually expressed as a dose/effect relationship, and considerable uncertainty exists concerning low exposure doses. In addition to the linear dose/effect relationship, low-dose studies might be based on a threshold dose/ effect relationship or the hormesis phenomenon (Burlakova et al., 2004;Calabrese, 2014;Baldwin and Grantham, 2015;Kudryasheva and Rozhko, 2015;Rozhko et al., 2016). The hormesis hypothesis suggests that low dose radiation can be favorable for living organisms. ...
... Modern microplate biochemiluminometers provide a technical support for such investigations. A review by Kudryasheva and Rozhko (2015) summarized the study of the effects of model solutions of alphaand beta-emitting radionuclides (americium-241, uranium, and tritium) on marine bacteria under conditions of chronic low-dose irradiation. Non-linear dose-effect dependences were demonstrated. ...
... Our previous works showed that the responses of luminous marine bacteria to the low-dose radiation of alpha and beta types [14][15][16][17][18][19][20][21]27,28] correspond to the conventional "hormesis" model [29][30][31][32]. This model includes, in the broadest case, three stages of the biological dose-dependent response-stress recognition, activation, and inhibition of organismal functions. ...
... It is seen that all three dependencies involve moderate bioluminescence activation (I rel >1) during the initial stage of exposure as well as an absence of effects during the last stage of the exposure. Activation of bacterial bioluminescence was previously observed in diluted solutions of another alpha-emitting radionuclide, americium-241, with higher energy of radioactive decay [14,18,20,21]; the effect was attributed to radiation hormesis. ...
Thorium is one of the most widespread radioactive elements in natural ecosystems, along with uranium, it is the most important source of nuclear energy. However, the effects of thorium on living organisms have not been thoroughly studied. Marine luminescent bacteria and their enzymes are optimal bioassays for studying low-dose thorium exposures. Luminescent bioassays provide a quantitative measure of toxicity and are characterized by high rates, sensitivity, and simplicity. It is known that the metabolic activity of bacteria is associated with the production of reactive oxygen species (ROS). We studied the effects of thorium-232 (10−11–10−3 M) on Photobacterium phosphoreum and bacterial enzymatic reactions; kinetics of bacterial bioluminescence and ROS content were investigated in both systems. Bioluminescence activation was revealed under low-dose exposures (<0.1 Gy) and discussed in terms of “radiation hormesis”. The activation was accompanied by an intensification of the oxidation of a low-molecular reducer, NADH, during the enzymatic processes. Negative correlations were found between the intensity of bioluminescence and the content of ROS in bacteria and enzyme systems; an active role of ROS in the low-dose activation by thorium was discussed. The results contribute to radioecological potential of bioluminescence techniques adapted to study low-intensity radioactive exposures.
... In our previous studies, we demonstrated a positive response of luminous bacteria to low-dose radiation exposure. The results of a series of investigations were summarized in a review [62]. Independency of the bacterial luminescent response on active concentration of beta-emitting radionuclide tritium was demonstrated for intact and lyophilized bacteria in a wide radioactivity interval: 10 -4 -200 MBq/L [22]. ...
... Earlier [65], a role of aqueous medium in antiradical activity of fullerenols was discussed. According to [62,66], reactive oxygen species in aqueous media might contribute to bacterial bioluminescence activation under low-dose exposures. ...
Fullerenols are nanosized water-soluble polyhydroxylated derivatives of fullerenes, specific allotropic form of carbon, bioactive compounds and perspective pharmaceutical agents. Antioxidant activity of fullerenols was studied in model solutions of organic and inorganic toxicants of oxidative type – 1,4-benzoquinone and potassium ferricyanide. Two fullerenol preparations were tested: С60О2-4(ОН)20–24 and mixture of two types of fullerenols С60О2-4(ОН)20–24+С70О2-4(ОН)20–24. Bacteria-based and enzyme-based bioluminescent assays were used to evaluate a decrease in cellular and biochemical toxicities, respectively. Additionally, the enzyme-based assay was used for the direct monitoring of efficiency of the oxidative enzymatic processes. The bacteria-based and enzyme-based assays showed similar peculiarities of the detoxification processes: (1) ultralow concentrations of fullerenols were active (ca 10–17-10⁻⁴ and 10–17-10⁻⁵g/L, respectively), (2) no monotonic dependence of detoxification efficiency on fullerenol concentrations was observed, and (3) detoxification of organic oxidizer solutions was more effective than that of the inorganic oxidizer. The antioxidant effect of highly diluted fullerenol solutions on bacterial cells was attributed to hormesis phenomenon; the detoxification was concerned with stimulation of adaptive cellular response under low-dose exposures. Sequence analysis of 16S ribosomal RNA was carried out; it did not reveal mutations in bacterial DNA. The suggestion was made that hydrophobic membrane-dependent processes are involved to the detoxifying mechanism. Catalytic activity of fullerenol (10⁻⁸g/L) in NADH-dependent enzymatic reactions was demonstrated and supposed to contribute to adaptive bacterial response.
... Suppression of the bioluminescent intensity evaluates toxicity of aqueous solutions, while the bioluminescence activation serves as an evidence of improving the luminescent physiological function. The last decade has seen the application of luminous bacteria to monitor biological effects of low-dose ionizing radiation (16)(17)(18). Due to simplicity and high rates of test procedure, bacteria-based bioluminescent assay makes it possible to simultaneously analyze many test samples, and, therefore, perform a proper statistical treatment of low-dose effects. ...
... Bacterial bioluminescent assays can be based on biological systems of different complexity-bacteria or their enzymes, providing comparison of toxic effects on microorganisms or their enzymatic reactions (12,(16)(17)(18)(19)(20). These assays allow for studying the mechanisms of toxic effects at cellular or molecular levels, respectively. ...
A bioluminescent assay based on a system of coupled enzymatic reactions catalyzed by bacterial luciferase and NADH:FMN-oxidoreductase was developed to monitor toxicity and antioxidant activity of bioactive compounds. The assay enables studying toxic effects at the level of biomolecules and physicochemical processes, as well as determining the toxicity of general and oxidative types. Toxic and detoxifying effects of bioactive compounds were studied. Fullerenols, perspective pharmaceutical agents, nanosized particles, water-soluble polyhydroxylated fullerene-60 derivatives were chosen as bioactive compounds. Two homologous fullerenols with different number and type of substituents, C60O2-4(OH)20-24 and Fe0.5C60(OH)xOy (x+y=40-42), were used. They suppressed bioluminescent intensity at concentrations > 0.01 g L−1 and > 0.001 g L−1 for C60O2-4(OH)20-24 and Fe0.5C60(OH)xOy, respectively, hence, a lower toxicity of C60O2-4(OH)20-24 was demonstrated. Antioxidant activity of fullerenols was studied in model solutions of organic and inorganic oxidizers; changes in toxicities of general and oxidative type were determined; detoxification coefficients were calculated. Fullerenol C60O2-4(OH)20-24 revealed higher antioxidant ability at concentrations 10-17-10-5 g L−1. The difference in the toxicity and antioxidant activity of fullerenols was explained through their electron donor/acceptor properties and different catalytic activity. Principles of bioluminescent enzyme assay application for evaluating the toxic effect and antioxidant activity of bioactive compounds were summarized. This article is protected by copyright. All rights reserved.
... UV-C radiation primarily induces direct DNA damage due to its strong absorption at wavelengths below 320 nm, while UV-B and UV-A radiation can cause indirect DNA damage by generating ROS (Kumar, Ghosh, and Kumar, 2020). Decay-related radiation, such as alpha and gamma radiation, are also associated with ROS production, whereas beta radiation appears to disrupt cellular processes and interfere with certain cellular structures, resulting in damage (Kudryasheva and Rozhko, 2015;Slade and Radman, 2011). ...
... Tritium (3 H), present in nuclear reactors as a by-product or reaction source, is a highly mobile, radioactive isotope of hydrogen (halflife of 12.3 years) and has already been shown to be radiotoxic in the environment [12][13][14][15]. Tritium easily exchanges with water to form tritiated water, and can also bind to carbon chains of organic molecules [14,[16][17][18]. ...
... Simplicity, sensitivity, and a high registration rate of the emission intensity make bioluminescent tests convenient and widely applied. The marine luminescent bacterium is one of the most common bioassays that has been widely used for more than 50 years to monitor the toxicity of media due to its high sensitivity to toxicants [11][12][13]. Another type of bioluminescent assay, the bacterial bioluminescent enzyme system, was suggested in 1990 [14]. ...
The current paper considers the effects of a water-soluble polymer (polyethylene glycol (PEG)) on the bioluminescent reaction of the photoprotein obelin from the marine coelenterate Obelia longissima and the product of this bioluminescent reaction: a coelenteramide-containing fluorescent protein (CCFP). We varied PEG concentrations (0–1.44 mg/mL) and molecular weights (1000, 8000, and 35,000 a.u.). The presence of PEG significantly increased the bioluminescent intensity of obelin but decreased the photoluminescence intensity of CCFP; the effects did not depend on the PEG concentration or the molecular weight. The photoluminescence spectra of CCFP did not change, while the bioluminescence spectra changed in the course of the bioluminescent reaction. The changes can be explained by different rigidity of the media in the polymer solutions affecting the stability of the photoprotein complex and the efficiency of the proton transfer in the bioluminescent reaction. The results predict and explain the change in the luminescence intensity and color of the marine coelenterates in the presence of water-soluble polymers. The CCFP appeared to be a proper tool for the toxicity monitoring of water-soluble polymers (e.g., PEGs).
... The effect of radiation hormesis refers to low-dose of radiation, including ionizing radiation and UV-B radiation, that can activate physiological functions and, along with their suppression, has been widely studied (Kudryasheva and Rozhko, 2015;Volkova et al., 2022;Zhong et al., 2022). Low-dose radiation hormesis of tritium has also been reported. ...
Tritium is the main component of radioactive wastewater from nuclear power plants and can be migrated into organisms to form organically bound tritium (OBT), which may pose a potential risk to aquatic ecosystem. Hence, it is essential to monitor OBT conversion in the presence of tritium exposure. In this study, the effects of pretreatment methods such as digestion on the recovery of tritium were discussed. It was found that microwave digestion pretreatment could improve the recovery of tritium by up to 90% and allow OBT measurement with a small sample size equivalent to about 60 mg (dry weight). In addition, the efficiency of OBT transformation was different among biological samples, and the radiation hormesis phenomenon was induced by tritium exposure (3.7 × 106 Bq/L) in microalgae Chlorella vulgaris（C. vulgaris）. The tritium exposure may induce radiation hormesis through the reactive oxygen species (ROS) signaling pathway, thus improving the photosynthetic capacity and metabolism level of C. vulgaris. Furthermore, enhancement of photorespiration metabolism and the antioxidation system may be important means for C. vulgaris to balance damage by tritium radiation. This study provides insights for further investigating OBT behavior, and will contribute to understanding the equilibrium damage mechanism of algae exposed to tritium.
... In various studies (Massimi, 2018;Vasić et al., 2020), it has been shown that the germination index is most affected by Cd, followed by Ni, and finally by Pb. In the environment, a small dose of a toxic substance can have a positive effect on the early developmental stage of plants, so-called hormesis (Kudryasheva & Rozhko, 2015); nevertheless, as the concentration of toxic compounds increases, the plant response changes, and the high dose of the toxic compound begins to have an inhibitory or toxic effect. ...
Cigarette butts (CBs) have only recently begun to be considered environmentally harmful waste. CBs are common waste in the environment, that can cause air, soil, and water pollution and pose a threat to the living. CBs should be treated as toxic and hazardous waste due to its slow decomposition and accumulation of many toxic substances. There is a lack of research on the adaptation of CBs to the environment and what impact they have on vegetation. Therefore, the present work aimed to understand the toxicity of smoked CBs. Leachates of various concentrations were assessed with ecotoxicological tests. The effect of CBs on germination and development of plants at their early stage of growth was determined. Seeds of Sinapis alba L. and Hordeum vulgare L. were used in the CBs toxicity test. Two-way ANOVA was conducted to compare the main effects on plants. From the results, it is evident that low concentrations of toxic substances contained in CBs have a positive effect on plants; however, Hordeum vulgare L. expresses higher toxic resistance than Sinapis alba L. It has been proven that high concentrations of CBs in a water solution have negative effects on seed germination and radical growth. This research shows that varied plant species can cope with different levels of contamination by hazardous elements. CBs are an important source of contamination for the environment and the hazardous elements that are released from them when inappropriately disposed of can impair the development of plants and accumulate in them.
... Critically, prokaryotes also display dose-related biphasic effects to ROS, for instance, when generated by ionizing radiation [46], suggesting that the process is very old. ...
Inflammation as a biological concept has been around a long time and derives from the Latin “to set on fire” and refers to the redness and heat, and usually swelling, which accompanies injury and infection. Chronic inflammation is also associated with ageing and is described by the term “inflammaging”. Likewise, the biological concept of hormesis, in the guise of what “does not kill you, makes you stronger”, has long been recognized, but in contrast, seems to have anti-inflammatory and age-slowing characteristics. As both phenomena act to restore homeostasis, they may share some common underlying principles. Thermodynamics describes the relationship between heat and energy, but is also intimately related to quantum mechanics. Life can be viewed as a series of self-renewing dissipative structures existing far from equilibrium as vortexes of “negentropy” that ages and dies; but, through reproduction and speciation, new robust structures are created, enabling life to adapt and continue in response to ever changing environments. In short, life can be viewed as a natural consequence of thermodynamics to dissipate energy to restore equilibrium; each component of this system is replaceable. However, at the molecular level, there is perhaps a deeper question: is life dependent on, or has it enhanced, quantum effects in space and time beyond those normally expected at the atomistic scale and temperatures that life operates at? There is some evidence it has. Certainly, the dissipative adaptive mechanism described by thermodynamics is now being extended into the quantum realm. Fascinating though this topic is, does exploring the relationship between quantum mechanics, thermodynamics, and biology give us a greater insight into ageing and, thus, medicine? It could be said that hormesis and inflammation are expressions of thermodynamic and quantum principles that control ageing via natural selection that could operate at all scales of life. Inflammation could be viewed as a mechanism to remove inefficient systems in response to stress to enable rebuilding of more functional dissipative structures, and hormesis as the process describing the ability to adapt; underlying this is the manipulation of fundamental quantum principles. Defining what “quantum biological normality” is has been a long-term problem, but perhaps we do not need to, as it is simply an expression of one end of the normal quantum mechanical spectrum, implying that biology could inform us as to how we can define the quantum world.
... The radioprotective properties of humic substances, products of natural oxidative decomposition of organic compounds in soils, were also demonstrated in solutions of alpha-and beta-emitting radionuclides [45][46][47][48]. Our previous works have revealed that bacterial responses to low-dose exogenous compounds correspond to the "hormesis" model [49,50]. This biological response is characterized by three main stages: stress recognition, stimulation, and subsequent inhibition of organism vital functions, i.e., toxicity [51][52][53][54]. ...
Our current study aimed to adapt a bioluminescent bacteria-based bioassay to monitor the bioeffects of gold nanoparticles (AuNPs). Luminous marine bacteria Photobacterium phosphoreum and AuNPs modified with polyvinylpyrrolidone were employed; low-concentration (≤10−3 g/L) bioeffects of AuNPs were studied. Bioluminescence intensity was used as an indicator of physiological activity in bacteria. Two additional methods were used: reactive oxygen species (ROS) content was estimated with a chemiluminescent luminol method, and bacterial size was monitored using electron microscopy. The bacterial bioluminescent response to AuNPs corresponded to the “hormesis” model and involved time-dependent bioluminescence activation, as well as a pronounced increase in the number of enlarged bacteria. We found negative correlations between the time courses of bioluminescence and the ROS content in bacterial suspensions, demonstrating the relationship between bioluminescence activation and bacterial ROS consumption. The combined effects of AuNPs and a beta-emitting radionuclide, tritium, revealed suppression of bacterial bioluminescent activity (as compared to their individual effects) and a reduced percentage of enlarged bacteria. Therefore, we demonstrated that our bacteria-based bioluminescence assay is an appropriate tool to study the bioeffects of AuNPs; the bioeffects can be further classified within a unified framework for rapid bioassessment.
... This suggests that LDIR can enhance the survival rate of microbial cells. The further observations found that some cells of E. coli cultivated with LDIR became morphologically smaller and shrunk more ( Fig. 4), which signified that they might stay in a particular dormant state for retard of nutrient transport, respiration rate and macromolecules synthesis [26,27]. ...
Microbial diversity is essential for the maintenance of the normal structure and function of bioregenerative life support systems (BLSS). As a typical nutrient-deficient environment (NDE), the BLSS does not provide sufficient types of available substrates for microbial communities, and its internal microbial diversity is usually not high due to interspecific competitive exclusion. However, it is reported that microbial diversity is abnormally high in the International Space Station (ISS) after long-term exposure to low-dose ionizing radiation (LDIR). It remains a mystery why LDIR leads to the formation and maintenance of high microbial diversity. In this study, a series of artificial microbial communities have been cultivated in NDE without and with LDIR, respectively. These communities are composed of three common microbial species (Escherichia coli, Pseudomonas aeruginosa, and Bacillus subtilis) in the ISS. By comparing and analyzing the differences in the microbial physiological and behavioral response characteristics in the two scenarios, a reasonable hypothesis was put forward to elucidate the formation and maintenance mechanisms of high microbial diversity in NDE with LDIR. Then a set of kinetic models were developed based on this hypothesis, observed phenomena, and experimental data. Finally, these kinetic models were sufficiently validated and the hypothesis was fully confirmed through large-scale digital simulations. Briefly, two fundamental succession mechanisms of the microbial communities are supposed to exist in NDE with LDIR: substrate-based negative feedback regulation (SNFR) and microbial delayed responses. These two decisive succession mechanisms can give rise to asynchronously convergent fluctuations of microbial populations and significantly alleviate the interspecific competitions. Such a species-for-quantity strategy drives the microbial communities to form and maintain a species diversity with higher richness and evenness. This study can lay the theoretical foundation and provide new ideas for the construction of advanced BLSS featured with more robust structures and stronger function.
... Crocin is found to have cancer-opposing activity against specific tumor cells (Bakshi et al., 2017). It reduces the damage caused by DNA breakage caused by hydroxyl radicals produced due to radiation (Kudryasheva & Rozhko, 2015). There is documentation indicating the protective effects of crocin against radiation poisoning of the kidneys, heart, liver, and skeletal muscles (Samarghandian et al., 2016). ...
Phytochemicals accessible in food have demonstrated efficiency against impairment by gamma radiation. The review presented here is an attempt to show the pharmacological outline of the activity of the natural antioxidants and its primary action of molecular mechanism against the damage induced by gamma rays. This research focused on the results of the in vitro dosage of natural antioxidants relationship, and on the correlation of this information with the statistical variables. Moreover, it deliberated the natural compounds which could decrease the unwelcome impacts of gamma radiation and safeguard biological systems from radiation‐stimulated genotoxicity. The outcomes indicated that natural compounds can be utilized as an adjunct to orthodox radiotherapy and cultivate it as an effectual drug for the clinical administration of ailments. This is the first comprehensive review that collected all naturally occurring antioxidants in foods that act as protective agents against damage caused by exposure to gamma rays. There was no such comprehensive study reviewing the effectiveness of natural antioxidants present in food against the danger of gamma‐ray. This review focused on the antioxidants that act as preventive and therapeutic agents against the danger resulting from radiation.
... Bioluminescence intensity was used as physiologic parameter to study the effects of exposure to alpha-and beta-emitting radionuclides (americium-241, uranium-235 + 238, and tritium). Three successive stages of response were detected: 1) the absence of effects (stress recognition); 2) activation (adaptive response); and, 3) Inhibition (suppression of physiological function, i.e., radiation toxicity) [15]. ...
A dose-response relationship to stressors, according to the hormesis theory, is characterized by low-dose stimulation and high-dose inhibition. It is non-linear with a low-dose optimum. Stress responses by cells lead to adapted vitality and fitness. Physical stress can be exerted through heat, radiation, or physical exercise. Chemical stressors include reactive species from oxygen (ROS), nitrogen (RNS), and carbon (RCS), carcinogens, elements, such as lithium (Li) and silicon (Si), and metals, such as silver (Ag), cadmium (Cd), and lead (Pb). Anthropogenic chemicals are agrochemicals (phytotoxins, herbicides), industrial chemicals, and pharmaceuticals. Biochemical stress can be exerted through toxins, medical drugs (e.g., cytostatics, psychopharmaceuticals, non-steroidal inhibitors of inflammation), and through fasting (dietary restriction). Key-lock interactions between enzymes and substrates, antigens and antibodies, antigen-presenting cells, and cognate T cells are the basics of biology, biochemistry, and immunology. Their rules do not obey linear dose-response relationships. The review provides examples of biologic stressors: oncolytic viruses (e.g., immuno-virotherapy of cancer) and hormones (e.g., melatonin, stress hormones). Molecular mechanisms of cellular stress adaptation involve the protein quality control system (PQS) and homeostasis of proteasome, endoplasmic reticulum, and mitochondria. Important components are transcription factors (e.g., Nrf2), micro-RNAs, heat shock proteins, ionic calcium, and enzymes (e.g., glutathion redox enzymes, DNA methyltransferases, and DNA repair enzymes). Cellular growth control, intercellular communication, and resistance to stress from microbial infections involve growth factors, cytokines, chemokines, interferons, and their respective receptors. The effects of hormesis during evolution are multifarious: cell protection and survival, evolutionary flexibility, and epigenetic memory. According to the hormesis theory, this is true for the entire biosphere, e.g., archaia, bacteria, fungi, plants, and the animal kingdoms.
... Dose-response studies are proposing hormesis as a central dose-response phenomenon for a variety of stressors [8,[35][36][37][38][39][40]. Hormesis is a widespread phenomenon usual in nature, independent of the kind of stressor, the physiological process or the organism it occurs [8,[35][36][37][38]. ...
Five-day exposure of clary sage (Salvia sclarea) to 100 μM cadmium (Cd) in hydroponics was sufficient to increase Cd concentrations significantly in roots and aboveground parts and affect negatively whole plant levels of calcium (Ca) and magnesium (Mg), since Cd competes for Ca channels, while reduced Mg concentrations are associated with increased Cd tolerance. Total zinc (Zn), copper (Cu), and iron (Fe) uptake increased but their translocation to the aboveground parts decreased possible due to translocation barriers. Despite the substantial levels of Cd in leaves, without any observed defects on chloroplast ultrastructure, an enhanced photosystem II (PSII) efficiency was observed, with a higher fraction of absorbed light energy to be directed to photochemistry (ΦPSΙΙ). The concomitant increase in the photoprotective mechanism of non-photochemical quenching of photosynthesis (NPQ) resulted in an important decrease in the dissipated non-regulated energy (ΦNO), modifying the homeostasis of reactive oxygen species (ROS), through a decreased singlet oxygen (1O2) formation. Thus, when clary sage was exposed to Cd for a short period, tolerance mechanisms were triggered, with PSII photochemistry to be regulated by NPQ in such a way that PSII efficiency to be enhanced. However, exposure to a combination of Cd and high light or for longer duration (8 days) to Cd alone, resulted in an inhibition of PSII functionality pointing out towards Cd toxicity. Thus, the rapid activation of PSII functionality at short time exposures and the inhibition at longer duration suggests a hormetic response and describes these effects in terms of “adaptive response” and “toxicity”, respectively.
... This stage is followed by weakening under chronic exposures [29,30]. Selye's syndrome is described by the 'hormesis' model, which suggests that low-dose effects induce activation of physiological functions; further chronic dose accumulation reduces the activating effect and evolves into an inhibitory (toxic) effect [31][32][33][34][35]. Probably, the increase in the size of needles in 2007 in pine stand 'A' allowed the trees to compensate the decrease in the productivity of photosynthesis when the needle surface was polluted and gas exchange was affected. ...
Five permanent sample plots (SPs; 200–250 trees per plot) were established in middle-aged high-grade suburban pine stands near the industrial city of Krasnoyarsk, Siberia, Russia. Needle damage, inventory parameters of the stands, and the defense response of the stem phloem were evaluated annually for the years 2002–2019 and attributed to acute or chronic toxic exposures (creeping fire or industrial pollutants, respectively). The results form a basis for using trees as bioindicators. A newly elaborated stem lesion test was formed from a hypothesis on the upward sugar transport for the regeneration of an injured crown, based on Eschrich's model of bidirectional sugar transport in the phloem. The formation of a phloem lesion was induced by inoculation of the stem with a mycelial extract of the ophiostomatoid fungus Ceratocystis laricicola. The lesion length and its shift relative to the inoculation hole were measured. An increase in the length of needles at early stages of stand weakening by pollutants was found to correspond to the hormesis model (Selye’s adaptation syndrome). A possibility of assessing the chronology of pollutant toxicity and the duration of the recovery period after creeping fire was shown.
... However, these highly unstable hydroxyl radicals can be scavenged by Cl − ions which are present at very high concentrations in physiological medium. This leads to the generation of active chlorine species (ACS) [6][7][8][9], among which relatively stable ClO − was suggested as the radiation-derived toxicant [6]. HOCl (ClO − ), a potent oxidant, however, can also be produced by neutrophils containing activated myeloperoxidase (MPO), which catalyzes the reaction between physiologically present chloride ions and hydrogen peroxide (H 2 O 2 ) [10]. ...
Background:
Radiation exposure of tissues is associated with inflammatory cell influx. Myeloperoxidase (MPO) is an enzyme expressed in granulocytes, such as neutrophils (PMN) and macrophages, responsible for active chlorine species (ACS) generation. The present study aimed to: 1) determine whether exposure to γ-irradiation induces MPO-dependent ACS generation in murine PMN; 2) elucidate the mechanism of radiation-induced ACS generation; and 3) evaluate the effect of the synthetic lignan LGM2605, known for ACS scavenging properties.
Methods:
MPO-dependent ACS generation was determined by using hypochlorite-specific 3'-(p-aminophenyl) fluorescein (APF) and a highly potent MPO inhibitor, 4-aminobenzoic acid hydrazide (ABAH), and confirmed in PMN derived from MPO-/- mice. Radiation-induced MPO activation was determined by EPR spectroscopy and computational analysis identified tyrosine, serine, and threonine residues near MPO's active site.
Results:
γ-radiation increased MPO-dependent ACS generation dose-dependently in human MPO and in wild type murine PMN, but not in PMN from MPO-/- mice. LGM2605 decreased radiation-induced, MPO-dependent ACS. Protein tyrosine phosphatase (PTP) and protein serine/threonine phosphatase (PSTP) inhibitors decreased the radiation-induced increase in ACS. Peroxidase cycle results demonstrate that tyrosine phosphorylation blocks MPO Compound I formation by preventing catalysis on H2O2 in the active site of MPO. EPR data demonstrate that γ- radiation increased tyrosyl radical species formation in a dose-dependent manner.
Conclusions:
We demonstrate that γ-radiation induces MPO-dependent generation of ACS, which is dependent, at least in part, by protein tyrosine and Ser/Thr dephosphorylation and is reduced by LGM2605. This study identified for the first time a novel protein dephosphorylation-dependent mechanism of radiation-induced MPO activation.
... exhibited a beneficial stimulatory effect, known as hormesis, upon the photobacteria (Fig. 3). This effect occurs with luminescent bacteria as a consequence of exposure to small concentrations of toxic chemicals [73]. As shown in Fig. 3, acute toxicity was generated during the UV-C photolysis of FRSM, but was eliminated within 600 mJ cm −2 of incident energy, when this process reached FRSM removal of 80% (Fig. 2). ...
In this study, the degradation of four emerging contaminants losartan potassium (LP), furosemide (FRSM), caffeine (CAF), and carbendazim (CBZ) under UV-C, UV-C/H2O2, and UV-C/S2O82− was investigated. A comparative evaluation of the efficiency of UV-C/H2O2 and UV-C/S2O8 2− in the degradation of these target CECs has not yet been reported.
Moreover, target compounds were submitted to UV-C/AOPs individually in pure water and their simultaneous degradation
was investigated in real surface water. Evolution of the acute toxicity of each compound during treatment was evaluated using Alivibrio fischeri. Quantum yields were determined for LP (0.011–0.016), FRSM (0.024–0.092), CAF (0.0007–0.0009), and CBZ (0.0016–0.0036) at different pH values. UV-C/H2O2 and UV-C/S2O82- achieved more than
98% removal of all compounds within 600 mJ cm−2, and pseudo-fist-order kinetic constants (k′app) for the degradation reactions were up to seven times higher in the presence of these oxidants when compared to k′app values obtained for UVC photolysis. k′app measured for UV-C/H2O2 were higher than those calculated for UV-C/S2O82− except in the case of LP.
Acute toxicity analysis suggested the formation of toxic intermediates during the UV-C photolysis of LP and FRSM, and the degradation of LP via UV-C/S2O82− also enhanced acute toxicity although electric energy efficiency per order identified UV-C/S2O82- as the most efficient process for the removal of this compound. Finally, different transformation products obtained during the degradation of caffeine under the different UV-C AOPs suggested that distinct degradation
routes were involved in each treatment tested.
... In the present study, before treatment, the FRSM solution exhibited a beneficial stimulatory effect, known as hormesis, upon the photobacteria (Fig. 3). This effect occurs with luminescent bacteria as a consequence of exposure to small concentrations of toxic chemicals [73]. As shown in Fig. 3, acute toxicity was generated during the UV-C photolysis of FRSM, but was eliminated within 600 mJ cm −2 of incident energy, when this process reached FRSM removal of 80% (Fig. 2). ...
In this study, the degradation of four emerging contaminants losartan potassium (LP), furosemide (FRSM), caffeine (CAF), and carbendazim (CBZ) under UV-C, UV-C/H2O2, and UV-C/S2O8²⁻ was investigated. A comparative evaluation of the efficiency of UV-C/H2O2 and UV-C/S2O8²⁻ in the degradation of these target CECs has not yet been reported. Moreover, target compounds were submitted to UV-C/AOPs individually in pure water and their simultaneous degradation was investigated in real surface water. Evolution of the acute toxicity of each compound during treatment was evaluated using Alivibrio fischeri. Quantum yields were determined for LP (0.011–0.016), FRSM (0.024–0.092), CAF (0.0007–0.0009), and CBZ (0.0016–0.0036) at different pH values. UV-C/H2O2 and UV-C/S2O8² achieved more than 98% removal of all compounds within 600 mJ cm⁻², and pseudo-fist-order kinetic constants (k′app) for the degradation reactions were up to seven times higher in the presence of these oxidants when compared to k′app values obtained for UV-C photolysis. k′app measured for UV-C/H2O2 were higher than those calculated for UV-C/S2O8²⁻ except in the case of LP. Acute toxicity analysis suggested the formation of toxic intermediates during the UV-C photolysis of LP and FRSM, and the degradation of LP via UV-C/S2O8²⁻ also enhanced acute toxicity although electric energy efficiency per order identified UV-C/S2O8² as the most efficient process for the removal of this compound. Finally, different transformation products obtained during the degradation of caffeine under the different UV-C AOPs suggested that distinct degradation routes were involved in each treatment tested.
... LGM2605 also prevented radiation-induced damage to genomic and plasmid DNA [17]. Until recently, the biological effects of ionizing radiation were associated with oxidative stress caused by the reactive oxygen species (ROS) [18][19][20]. We have shown that gamma radiation of physiological solutions induces generation of active chlorine species (ACS) formed by interaction of ROS and Cl − and LGM2605 scavenges radiation-induced ACS, both primary ACS radicals such as chlorine atoms and secondary ACS hypochlorite [21]. ...
... induction of hormonal response) and reactivity of the living organism, i.e. the cellular context. Adaptation to disarrangement of the physiological agents (hormesislike response) appears crucial for functioning of various living entities, from bacteria [152] to vertebrates [50]. It is also hierarchically conserved from the level of the single cell [19] up to the entire organism [8]. ...
Finite disarrangements of important (vital) physiological agents can induce plethora of beneficial effects, exceeding mere attenuation of the specific stress. Such response to disrupted homeostasis appears to be universally conserved among species. The underlying mechanism of improved fitness and longevity, when physiological agents act outside their normal range is similar to hormesis, a phenomenon of whereby toxins elicit beneficial effects at low doses. Due to similarity with such non-linear response to toxins described with J-shaped curve, we have coined a new term “mirror J-shaped curves” for non-linear response to finite disarrangement of physiological agents. Examples from the clinical trials and basic research are provided, along with the unifying mechanisms that tie classical non-linear response to toxins with the non-linear response by physiological agents (glucose, oxygen, osmolarity, thermal energy, calcium, body mass, calorie intake and exercise). Reactive oxygen species and cytosolic calcium seem to be common triggers of signaling pathways that result in these beneficial effects. Awareness of such phenomena and exploring underlying mechanisms can help physicians in their everyday practice. It can also benefit researchers when designing studies and interpreting growing number of scientific data showing non-linear responses to physiological agents.
... Simple registration of luminescent test parameter imparts convenience and prospectivity to the proteinbased test system. Development of the protein-based colored biomarkers can form a physicochemical basis for understanding biological response to toxic exposures in luminescence assay systems of different complexity [15][16][17][18][19][20][21][22]. ...
The study addresses the application of fluorescent coelenteramide-containing proteins as color bioindicators for radiotoxicity evaluation. Biological effects of chronic low-dose radiation are under investigation. Tritiated water (200 MBq/L) was used as a model source of low-intensive ionizing radiation of beta type. 'Discharged obelin,' product of bioluminescent reaction of marine coelenterate Obelia longissimi, was used as a representative of the coelenteramide-containing proteins. Coelenteramide, fluorophore of discharged obelin, is a photochemically active molecule; it produces fluorescence forms of different color. Contributions of 'violet' and 'blue-green' forms to the visible fluorescence serve as tested parameters. The contributions depend on the coelenteramide's microenvironment in the protein, and, hence, evaluate distractive ability and toxicity of radiation. The protein samples were exposed to beta radiation for 18 days, and maximal dose accumulated by the samples was 0.28 Gy, being close to a tentative limit of a low-dose interval. Increase of relative contribution of 'violet' fluorescence under exposure to the beta irradiation was revealed. High sensitivity of the protein-based test system to low-dose ionizing radiation (to 0.03 Gy) was demonstrated. The study develops physicochemical understanding of radiotoxic effects. Graphical abstract Coelenteramide-containing protein (discharged obelin) changes fluorescence color under exposure to low-dose ionizing radiation of tritium.
... This accounts for intensive research on the structure and functions of luminous bacteria, as well as their sensitivity to exogenous compounds [17][18][19]. Development of bacteria-based ecological toxicity assay is now in a progress [17,[20][21][22][23], including radiation toxicity [24]. ...
... While ionising radiation has traditionally been considered toxic at any level, experiments at low radiation backgrounds provide a window to explore the contention that responses to radiation dosage are hormetic, and that a small radiation dose may stimulate cells [9][10][11]. Interpreted in this light, past experiments in underground laboratories show results consistent with radiation hormesis, in line with experiments showing non-linear dose-response relationships in marine bacteria [12]. Indeed, a myriad of biological responses have been shown to exist in recent years that suggest low radiation dosages can have unexpected impacts on cells, of which the bystander effect is the most notable [13,14]. ...
At very low radiation dose rates, the effects of energy depositions in cells by ionizing radiation is best understood stochastically, as ionizing particles deposit energy along tracks separated by distances often much larger than the size of cells. We present a thorough analysis of the stochastic impact of the natural radiative background on cells, focusing our attention on E. coli grown as part of a long term evolution experiment in both underground and surface laboratories. The chance per day that a particle track interacts with a cell in the surface laboratory was found to be 6 × 10⁻⁵ day⁻¹, 100 times less than the expected daily mutation rate for E. coli under our experimental conditions. In order for the chance cells are hit to approach the mutation rate, a gamma background dose rate of 20 μGy hr⁻¹ is predicted to be required.
... Moreover, recent studies showed that response of bacterial populations to ionizing radiation was dependent on various factors (chemical impurities, temperature conditions, etc.) (Shuryak and Dadachova, 2016). We do not think that our results contradict the data reported previously, as in order to detect the biological effect of low doses, it is very important to take measurements in the proper phase of bacterial cell response to ionizing radiation (Kudryasheva and Rozhko, 2015). This is also confirmed by the fact that as the time of exposure to the examined doses of ionizing radiation is increased, the frequencies of mutations gradually decline and become comparable to the frequencies of mutations in the control cultures (Tables 2 and 4). ...
This study addresses use of two bacterial test systems (the Ames test and the SOS chromotest) to estimate the effects of low doses of γ-radiation. The most substantial increases in induction of SOS response and mutation frequencies were observed in the first 24 h of exposure to γ-radiation as compared to the cells in the exposure-free control. Gamma-radiation also impaired growth and survival of S. typhimurium cells in the first 24 h. The effects were attenuated at lower exposure doses and at longer exposure times. In the experiments conducted in this study, at 96 h of exposure, the values of some of the γ-radiation effects were lower than the MID (minimum inducing dose) detection limits and, thus, were neglected. Long-term exposure to γ-radiation could also result in combined effects of γ-radiation and the death of cells in the culture.
Currently, it has been established that when living organisms are exposed to various environmental factors (abiotic, biotic, and anthropogenic), hormesis is a fairly common phenomenon. Hormesis is found in different groups of organisms and at almost all levels of the organization of living systems from the cell to ecosystem level. At the same time, a comprehensive analysis of the significance of hormesis for ecology has not been carried out. This review analyzes the modern concept of hormesis, as well as its significance for various fields of ecology.
—Currently, it has been established that when living organisms are exposed to various environmental
factors (abiotic, biotic, and anthropogenic), hormesis is a fairly common phenomenon. Hormesis is found in
different groups of organisms and at almost all levels of the organization of living systems from the cell to ecosystem
level. At the same time, a comprehensive analysis of the significance of hormesis for ecology has not
been carried out. This review analyzes the modern concept of hormesis, as well as its significance for various
fields of ecology.
Keywords: hormesis, stress, adaptation, organism, population, community
DOI: 10.1134/S2079086423090037
Jwa, M.S. and Hong, C.-Y., 2023. Abiotic stress tolerance of juvenile small abalone Haliotis diversicolor aquatilis (obunjagi) to gamma irradiation. Journal of Coastal Research, 39(1), 5562. Charlotte (North Carolina), ISSN 0749-0208. In South Korea, the small abalone (obunjagi), Haliotis diversicolor aquatilis, is a prominent commercial seafood species. However, summer circumstances frequently impede abalone productivity, emphasizing the need for suitable approaches to promote abalone viability. The purpose of this study was to see if the survival rate and physiological responses of juvenile H. diversicolor aquatilis changed after exposure to low-level 60Co-gamma irradiation under high temperature (HT) and low salinity (LS) stress conditions (20 Gy). For this research, juvenile small obunjagi, H. diversicolor aquatilis, were obtained from Jeju City fishing vendors, Korea. Before the experiment, all abalone samples were acclimated for 7 days in a seawater-filled tank at 23C 0.3C and 32 0.2 psu under starvation conditions. Seventy abalones (20 male and 50 female) were gamma irradiated and 30 abalones (10 male and 20 female) were used as controls. After 6 weeks of malnutrition, abalone survivability and the quantity of cardiovascular hemocytes rose dramatically after 20-Gy exposure compared with the control (0 Gy). The viability of abalone was dramatically reduced by HT stress but not by LS stress. The initially improved immune response-mediated hormetic impact might be connected to abalone survival rate under famine and HT stress, and the hormesis-induced gamma radiation exposure strategy will successfully raise abalone productivity throughout summer.
Our current study develops the application of suburban forests as bioindicators, with the industrial metropolis of Krasnoyarsk (Central Siberia, Russia) taken as an example. Huge forests, such as those found in large Siberian territories, are climate‐forming for the entire planet. Hence, their conservation is essential at both the local and global scales. During the period between 2002–2021, a vigor state of two pine forests was evaluated using several inventory and morphological parameters: needle damage, deterioration in tree condition, increased entropy, and tree mortality. Additionally, an original bioindication parameter was applied: episodic increase in the size of needles was analyzed. We hypothesized that this increase in needle size was related to the activation of tree protection at the initial stage of tree damage; the mechanism assumes a redirection of sugar transport into the crown to aid tree regeneration. All parameters were measured annually on 6 permanent sample plots; each plot included 200–300 numbered trees of similar age (about 60–80 years). The long‐term parameter changes were analyzed and attributed to chronic exposure to industrial air pollution. Significant changes in pine‐forest parameters observed over the past few years (2019–2021) may indicate an approaching stage of irreversible toxic damage i.e. the destruction of the entire forest system. The results encourage involving forest‐based bioindication in the regional system of ecological monitoring. Forest‐based bioindication can be used as a tool for evaluating the efficiency of long‐term governmental activity on air quality in industrial metropolises. This article is protected by copyright. All rights reserved.
The bioluminescent luciferin-luciferase reaction is based on the oxidation of D-luciferin by oxygen in the presence of ATP and magnesium ions, catalyzed by firefly luciferase. The possibilities of using this reaction to study the influence of external effectors of a physical and chemical nature (temperature exposure, additions of drugs, membrane-active compounds, etc.) on living cells (prokaryotes and eukaryotes) are considered. Examples of the use of test systems based on living cells producing thermostable firefly luciferase for monitoring cellular homeostasis are given. The study of the kinetics of changes in the concentration of ATP and luciferase inside and outside cells made it possible to determine in dynamics the metabolic activity, cytotoxicity, and survival of cells under conditions of cellular stress, to study the processes of ATP synthesis/hydrolysis, and to evaluate the effectiveness of lytic agents in changing the permeability of the cell membrane.
Internal contamination of actinides has led to significant health hazards to the public and workers in the context of nuclear power plant accidents, uranium ore mining, and reprocessing of the used fuel. An effective sequestering agent that is able to remove accidentally incorporated actinides in vivo with low toxicity is always in urgent need. The molecular decorporation ligands have been the most widely researched agents for the past few decades, while preliminary studies of functionalized nanoparticles have shown their clear advantages in metal binding selectivity, toxicity, and oxidative stress alleviation. Herein, the state-of-the-art of those two types of decorporation agents is presented with special attention being paid on the correlation between the solution and solid-state chemistry of those agents with actinides and the corresponding decorporation efficacies.
The planetary protection strives to minimize the contamination of microorganisms in spacecrafts. However, it is reported that microbial diversity is abnormally high in the International Space Station (ISS) after long-term exposure to low-dose ionizing radiation (LDIR). It remains a mystery why LDIR leads to the formation and maintenance of high microbial diversity in oligotrophic environments like the ISS. In this study, an artificial microbial community has been cultivated without and with LDIR, respectively. The microbial community was composed of three common microbial species, i.e., Bacillus subtilis, Escherichia coli and Pseudomonas aeruginosa in the ISS. After analyzing the differences in microbial physiological and behavioral response characteristics in the two scenarios, a reasonable hypothesis was proposed to elucidate the formation and maintenance mechanisms of high microbial diversity in oligotrophic environments with the LDIR. Then a set of kinetic models with time-lag were developed based on this hypothesis, observed phenomena, and experimental data. Finally, these kinetic models were sufficiently validated, and the hypothesis was fully confirmed through large-scale digital simulations. Briefly, as a decisive succession mechanism in oligotrophic environments with LDIR, temporal niche differentiation (TND) caused by microbial delayed responses to LDIR can give rise to asynchronously convergent fluctuations of microbial populations and significantly alleviate the intra- and interspecific competitions. Such a mechanism can drive the microbial communities in oligotrophic environments with LDIR to form and maintain high species diversity.
Silver antibacterial compounds (SACs) and quorum sensing inhibitors (QSIs), as the potential antibiotic substitutes, have been recommended to prevent and treat microbial infections for the purpose of controlling the increasingly serious bacterial resistance induced by the abuse of antibiotics. However, there is little information regarding the resistance risk of these compounds, especially their mixtures. In this study, bacterial mutation and RP4 plasmid conjugative transfer among bacteria were used to characterize the bacterial endogenous and exogenous resistance, respectively. The effects of SACs (including silver nitrate (AgNO3) and silver nanoparticle (AgNP)), QSIs, and their binary mixtures on the bacterial resistance were investigated via setting the frequency of mutation and conjugative transfer in Escherichia coli (E. coli) as the test endpoints. The results indicated that these two endpoints exhibited hormetic dose-responses to each treatment. Furthermore, the joint resistance actions between SACs and QSIs were all judged to be antagonism. Correlation analysis suggested that the promotion of the bacterial resistance in each treatment was closely related to its toxicity. It was speculated that AgNO3 and AgNP might both release Ag⁺ ions to facilitate the E. coli resistance, while QSIs probably acted on LsrR and SdiA proteins to stimulate the bacterial mutation and accelerate the RP4 plasmid conjugative transfer, respectively. These findings imply that the bacteria may generate targeted stress response to the survival pressure from environmental compounds, displaying hormetic phenomenon in resistance-related test endpoints. This study provides a new insight into the resistance risk induced by SACs and QSIs, benefiting the environmental risk assessment of these compounds from the perspective of bacterial resistance.
Hormesis is a biphasic dose-response relationship featured by low-dose stimulation and high-dose inhibition. Although the hormetic phenomenon has been extensively studied over the past decades, there is little information regarding the influence of energy source on the occurrence of hormesis, especially the time-dependent one. In this study, to explore the role of cultivation system’s energy source in time-dependent hormesis, the toxic dose-responses of Aliivibrio fischeri (A. fischeri) bioluminescence to Sulfadoxine (SDX) during 24 hours were determined in four cultivation systems with different energy source conditions. The results indicated that the time-dependent hormetic effects were induced by SDX in all cultivation systems: SDX triggered hormetic phenomenon on the bioluminescence at each growth stage over 24 hours in the cultivation systems with sufficient and insufficient energy source; due to the diauxic growth of A. fischeri under multiple energy source conditions, the hormetic effects of SDX gradually disappeared after the preferred energy source was used up. It was speculated that the inhibitory action of SDX was derived from its interaction with DHPS to impede the synthesis of proteins, and SDX bound with AC to upregulate the quorum sensing (QS) system to exhibit the stimulatory action. Comparing the time-dependent hormesis in each cultivation system, it was obtained that the energy source could impact the hourly maximum stimulatory rate, the EC50 of SDX, and the time point that hormesis occurred, which might result from the influence of energy source on the stimulatory and inhibitory actions of SDX through regulating the metabolic system (individual level) and QS system (group level) of bacteria. This study clarifies the importance of energy source for hormesis occurrence, which may further promote the development of hormesis.
Five-day exposure of clary sage (Salvia sclarea L.) to 100 μM cadmium (Cd) in hydroponics was sufficient to increase Cd concentrations significantly in roots and aboveground parts and affect negatively whole plant levels of calcium (Ca) and magnesium (Mg), since Cd competes for Ca channels, while reduced Mg concentrations are associated with increased Cd tolerance. Total zinc (Zn), copper (Cu), and iron (Fe) uptake increased but their translocation to the aboveground parts decreased. Despite the substantial levels of Cd in leaves, without any observed defects on chloroplast ultrastructure, an enhanced photosystem II (PSII) efficiency was observed, with a higher fraction of absorbed light energy to be directed to photochemistry (Φ
PSΙΙ
). The concomitant increase in the photoprotective mechanism of non-photochemical quenching of photosynthesis (NPQ) resulted in an important decrease in the dissipated non-regulated energy (Φ
NO
), modifying the homeostasis of reactive oxygen species (ROS), through a decreased singlet oxygen (1O2) formation. A basal ROS level was detected in control plant leaves for optimal growth, while a low increased level of ROS under 5 days Cd exposure seemed to be beneficial for triggering defense responses, and a high level of ROS out of the boundaries (8 days Cd exposure), was harmful to plants. Thus, when clary sage was exposed to Cd for a short period, tolerance mechanisms were triggered. However, exposure to a combination of Cd and high light or to Cd alone (8 days) resulted in an inhibition of PSII functionality, indicating Cd toxicity. Thus, the rapid activation of PSII functionality at short time exposure and the inhibition at longer duration suggests a hormetic response and describes these effects in terms of "adaptive response" and "toxicity", respectively.
Toxicity monitoring of harmful radiations is an indispensable issue of modern radioecology. As bioluminescent bacteria have the simplest structure to epitomize the biosphere also their bioluminescence can act as an indicator of the condition, hence assay systems based on luminous bacteria can be used as sensors for monitoring the environmental radiotoxicity. The present investigation explores the measurement of bacterial luminescence which can be easily computed. Further, the bioluminescent bacterial strains were used to evaluate the impact of UV and Gamma irradiations. Random Amplified Polymorphic DNA (RAPD) was carried out to observe alterations underexposure. Further by using a phylogenetic tree, a comparative study of the effect of UV and Gamma rays has been carried out. It has been revealed that the isolated strains have shown remarkable sensitivity towards radiation exposure present in the environment and therefore they could be used as the potential biosensing elements for developing an on-site pollution monitoring biosensor.
It remains a mystery why microbial community succession can violate the competitive exclusion principle to form high species diversity in nutrient-deficient environments (NDE) with low-dose ionizing radiation (LDIR). In this research, artificial microbial communities containing three common strains downloaded from China Tiangong-1 space station were cultivated in NDE with and without LDIR, respectively. By comparing their identities and differences in cellular phenotype, extracellular pH, intracellular triglycerides and population dynamics under the two circumstances, a new hypothesis was put forward from observed phenomena and experimental data to expound new interspecific relationships and interactions induced by LDIR to produce new dynamic mechanisms to drive microbial community succession with high species diversity. A set of highly valid kinetic models was then developed from this hypothesis, and finally, the hypothesis proposed was verified through a large number of digital simulations. The results show that induced by LDIR, specific feedback regulation of microbial populations by mutual promotion and restraint mechanisms might exist in microbial communities, which can cause asynchronous convergent fluctuations of microbial populations. These fluctuations remarkably alleviate interspecific competition and inhibit the emergence of dominant species, leading to the formation and maintenance of higher species diversity. The results can provide a theoretical basis for understanding the ecological effect of LDIR on microbial communities in NDE as well as its application for ecological engineering purposes.
In order to investigate the luminous responses of γ ray irradiation on Vibrio Qinghaiensis sp. Q67, two γ ray sources, ⁶⁰Co and ¹³⁷Cs, were used. Following the dose rates between 0.05Gy/min and 0.2Gy/min of ⁶⁰Co, the relative luminous value (RLV) of Q67 was less than 1 after 5 minutes irradiation and inversely related to dose rate. Irradiated 1 hour at dose rates range from 100nGy/h to 10mGy/h of ¹³⁷Cs, two successive stages in the luminous response were found: hormesis and inhibition. It was found that RLV was interleaved and could not be distinguished until inhibition stage appearance. The time when RLV drops to less than 1 (T0) was linear with the logarithm of dose rate. Experimental result indicates that Q67 is sensitive to acute γray radiation, which could be used to monitor γray radiation.
Limits in resource availability are driving a change in current societal production systems, changing the focus from residues treatment, such as wastewater treatment, towards resource recovery. Biotechnological processes offer an economic and versatile way to concentrate and transform resources from waste/wastewater into valuable products, which is a prerequisite for the technological development of a cradle-to-cradle bio-based economy. This review identifies emerging technologies that enable resource recovery across the wastewater treatment cycle. As such, bioenergy in the form of biohydrogen (by photo and dark fermentation processes) and biogas (during anaerobic digestion processes) have been classic targets, whereby, direct transformation of lipidic biomass into biodiesel also gained attention. This concept is similar to previous biofuel concepts, but more sustainable, as 3rd generation biofuels and other resources can be produced from waste biomass. The production of high value biopolymers (e.g. for bioplastics manufacturing) from organic acids, hydrogen, and methane is another option for carbon recovery. The recovery of carbon and nutrients can be achieved by organic fertilizer production, or single cell protein generation (depending on the source) which may be utilized as feed, feed additives, next generation fertilizers, or even as probiotics. Additionlly, chemical oxidation-reduction and bioelectrochemical systems can recover inorganics or synthesize organic products beyond the natural microbial metabolism. Anticipating the next generation of wastewater treatment plants driven by biological recovery technologies, this review is focused on the generation and re-synthesis of energetic resources and key resources to be recycled as raw materials in a cradle-to-cradle economy concept.
This is the first study to present data on the genotoxicity of low γ-irradiation doses for E. coli and S. typhimurium cells obtained using the SOS chromotest and the Ames test. The most pronounced effect was recorded in the first 24 h of γ-irradiation. After 72 h in the Ames test and after 96 h in the SOS chromotest, a significant effect of γ-irradiation on bacterial cells was detected. The absence of genotoxicity at the later stages can be explained by the adaptation of bacterial cells to the conditions of exposure. The findings allow the bacterial test system to be used for studying the effects of low doses at the early stages of exposure to radiation.
This paper assesses the hormesis dose response concept, including its historical foundations, frequency, generality, quantitative features, mechanistic basis and biomedical, pharmaceutical and environmental health implications. The hormetic dose response is highly generalizable, being independent of biology model (i.e. common from plants to humans), level of biological organization (i.e. cell, organ and organism), endpoint, inducing agent and mechanism, providing the first general and quantitative description of plasticity. The hormetic dose response describes the limits to which integrative endpoints (e.g. cell proliferation, cell migration, growth patterns, tissue repair, aging processes, complex behaviors such as anxiety, learning, memory, and stress, preconditioning responses, and numerous adaptive responses) can be modulated (i.e., enhanced or diminished) by pharmaceutical, chemical and physical means. Thus, the hormesis concept is a fundamental concept in biology with a wide range of biological implications and biomedical applications.
This month'ss featured article; “Stimulation of luminescence of mycelium of luminous fungus Neonothopanus nambi by ionizing radiation” is a joint contribution from two experimental teams from Novosibirsk and Krasnoyarsk, Russia. The work demonstrates that a moderate dose of X‐irradiation reproducibly causes a substantial boost in light production from a wide range of samples of fungus with intrinsic bioluminescence. The observed features of this enhancement strongly support involvement of reactive oxygen species in fungal light production.
Effects of Americium-241 (241Am), alpha-emitting radionuclide of high specific radioactivity, and tritium (3H), beta-emitting radionuclide, on luminous bacteria Photobacterium phosphoreum were compared. Bioluminescence intensity served as a marker of bacterial physiological activity. Three successive stages in the bioluminescence response to 241Am and 3H were found under conditions of lowdose irradiation: (1) absence of effects, (2) activation, and (3) inhibition. They were interpreted in terms of bacterial response to stressfactor as stress recognition, adaptive response/syndrome, and suppression of physiological function (i.e. radiation toxicity). Times of bioluminescence activation (TBA) and inhibition (TBI) were suggested as parameters to characterize hormesis and toxic stages in a course of chronic low-dose irradiation of the microorganisms. Values of TBA and TBI of 241Am were shorter than those of 3H, revealing higher impact of alpha-irradiation (as compared to beta-irradiation) under comparable radiation doses. Increases of peroxide concentration and NADH oxidation rates in 241Am aquatic solutions were demonstrated; these were not found in tritiated water. The results reveal a biological role of reactive oxygen species generated in water solutions as secondary products of the radioactive decay. The study provides a scientific basis for elaboration of bioluminescence-based assay to monitor radiotoxicity of alpha- and beta-emitting radionuclides in aquatic solutions.
Natural and manmade organic chemicals are widely deposited across a diverse range of ecosystems including air, surface water, groundwater, wastewater, soil, sediment, and marine environments. Some organic compounds, despite their industrial values, are toxic to living organisms and pose significant health risks to humans and wildlife. Detection and monitoring of these organic pollutants in environmental matrices therefore is of great interest and need for remediation and health risk assessment. Although these detections have traditionally been performed using analytical chemical approaches that offer highly sensitive and specific identification of target compounds, these methods require specialized equipment and trained operators, and fail to describe potential bioavailable effects on living organisms. Alternatively, the integration of bioluminescent systems into whole-cell bioreporters presents a new capacity for organic compound detection. These bioreporters are constructed by incorporating reporter genes into catabolic or signaling pathways that are present within living cells and emit a bioluminescent signal that can be detected upon exposure to target chemicals. Although relatively less specific compared to analytical methods, bioluminescent bioassays are more cost-effective, more rapid, can be scaled to higher throughput, and can be designed to report not only the presence but also the bioavailability of target substances. This chapter reviews available bacterial and eukaryotic whole-cell bioreporters for sensing organic pollutants and their applications in a variety of sample matrices.
Graphical Abstract
This review examines the general principles of bioluminescent enzymatic toxicity bioassays and describes the applications of these methods and the implementation in commercial biosensors. Bioluminescent enzyme system technology (BEST) has been proposed in the bacterial coupled enzyme system, wherein NADH:FMN-oxidoreductase-luciferase substitutes for living organisms. BEST was introduced to facilitate and accelerate the development of cost-competitive enzymatic systems for use in biosensors for medical, environmental, and industrial applications. For widespread use of BEST, the multicomponent reagent “Enzymolum” has been developed, which contains the bacterial luciferase, NADH:FMN-oxidoreductase, and their substrates, co-immobilized in starch or gelatin gel. Enzymolum is the central part of Portable Laboratory for Toxicity Detection (PLTD), which consists of a biodetector module, a sampling module, a sample preparation module, and a reagent module. PLTD instantly signals chemical–biological hazards and allows us to detect a wide range of toxic substances. Enzymolum can be integrated as a biological module into the portable biodetector–biosensor originally constructed for personal use. Based on the example of Enzymolum and the algorithm for creating new enzyme biotests with tailored characteristics, a new approach was demonstrated in biotechnological design and construction. The examples of biotechnological design of various bioluminescent methods for ecological monitoring were provided. Possible applications of enzyme bioassays are seen in the examples for medical diagnostics, assessment of the effect of physical load on sportsmen, analysis of food additives, and in practical courses for higher educational institutions and schools. The advantages of enzymatic assays are their rapidity (the period of time required does not exceed 3–5 min), high sensitivity, simplicity and safety of procedure, and possibility of automation of ecological monitoring; the required luminometer is easily available.
Graphical Abstract
The luminescent system of higher luminous fungi is not fully understood and the enzyme/substrate pair of the light emission reaction has not been isolated. It was suggested that luminescence of fungi involves oxidase-type enzymes, and reactive oxygen species are important for fungal light production. Generation of reactive oxygen species can be stimulated by ionizing irradiation, which has not been studied for luminous fungi. We report the effect of X-irradiation on the luminescence of fungus Neonothopanus nambi. Experiments were performed with mycelium on a home-built setup based on an X-ray tube and monochromator/photomultiplier tube. Application of X-rays does not change the emission spectrum, but after approximately 20 min of continuous irradiation, light production from unsupported mycelium starts growing and increases up to approximately five times. After peaking, its level decreases irrespective of the presence of X-irradiation. After staying at a certain level, light production collapses to zero, which is not related to the drying of the mycelium or thermal impact of radiation. The observed shape of kinetics is characteristic of a multistage and/or chain reaction. The time profile of light production must reflect the current levels of radicals present in the system and/or the activity of enzyme complexes involved in light production. Copyright © 2014 John Wiley & Sons, Ltd.
Optical based sensing systems that measure luminescence, fluorescence, reflectance and absorbance, etc., are some of the areas of applications of optical immunosensors. Immunological methods rely on specific binding of an antibody (monoclonal, polyclonal or engineered) to an antigen. Detection of specific microorganisms and microbial toxins requires immobilization of specific antibodies onto a given transducer that can produce signal upon attachment of typical microbe/microbial toxins. Inherent features of immunosensors such as specificity, sensitivity, speed, ease and on-site analysis can be made use for various applications. Safety of food and environment has been a major concern of food technologists and health scientists in recent years. There exists a strong need for rapid and sensitive detection of different components of foods and beverages along with the food borne and water borne pathogens, toxins and pesticide residues with high specificity. Biosensors present attractive, efficient alternative techniques by providing quick and reliable performances. There is a very good potential for application of biosensors for monitoring food quality and safety in food and bioprocessing industries in India.
Biotests are currently used for monitoring of ecological systems. Bioluminescent bacterial systems are applied instead of plants, fishes and other living organisms as test-objects [1-2]. The main principle of bioluminescent biotests is the correlation between the toxicity of the medium under study and its effect on the light intensity. Applying of the bioluminescent assays develops in two directions: the test-systems of BL bacteria (in vivo) and bioluminescent enzymic systems (in vitro). Reagents based on the test-organisms (e.g. lyophilized luminous bacteria) and on the enzymic systems (e.g. bacterial luciferase systems) are created. Luciferase biotesting is based on the inhibition of the enzymes’ activity by the components of a medium under study.
Action of metallic salts on the bacterial bioluminescent systems (1 - water-soluble coupled system luciferase - NADH:FMN-oxydoreductase; 2 - immobilized in starch gel coupled system luciferase -NADH:FMN-oxydoreductase; 3 - intact bacteria) has been studied. The action parameters have been calculated. The effects have been shown to depend on nature of cations but not anions Electronic structure of cations (nature of external orbitals, charge, radii) has been taken into account. Cations with similar electronic shells nature affect on the row of the bioluminescent systems mentioned above in a similar way Differences in effects have been explained with diffusion rate, cellular shell and respiration of bacteria.
Ionizing radiation produces a plethora of lesion upon DNA which sometimes is generated among a relatively small region due to clustered energy deposition events, the so called locally multiply damaged sites that could change to DSB. Such clustered damages are more likely to occur in high LET radiation exposures. The effect of alpha particles of different LET was evaluated on the bacterium Escherichia coli either by survival properties or the SOS response activity. Alpha radiation and LET distribution was controlled by means of Nuclear Track Detectors. The results suggest that alpha particles produce two types of lesion: lethal lesions and SOS inducing-mutagenic, a proportion that varies depending on the LET values. The SOS response as a sensitive parameter to assess RBE is mentioned.
For the first time the cytogenetic examination of the group of nuclear specialists (79 persons) chronically exposed to tritium beta-radiation for a long period was carried out. The frequencies of unstable (conventional method) and stable (FISH-method) chromosome aberrations have been analyzed. 50 years after the beginning of working under the conditions of the increased radiation level the differences (in comparison with control values) were revealed for all cytogenetic parameters. The frequency of the radiation-specific markers (dicentrics and centric rings) exceeds more than 2-fold the control level. A significant but poor correlation between the frequency of unstable aberrations and the total absorbed dose (during the whole working period) was revealed. A retrospective estimation of irradiation doses for 14 nuclear workers was made by the frequency of stable chromosome aberrations. The obtained dose values ranged from 110 to 1250 mSv.
Summarized are the results of extensive investigations of the responses of live systems to extremely weak influences. Consideration of the effects of ultralow concentrations of various biologically active substances and ultraweak physical (mainly electromagnetic) fields on biological systems of different organizational levels (molecular to population) reveals a number of unified regular features: polymodality of dose dependences, effectiveness of stimuli below the background intensity and its dependence on the sate of the system, modulation of the sensitivity of the system to subsequent (different) stimuli, etc. Several hypotheses are reviewed concerning the possible mechanisms of such influences and the role of water as a universal mediator in these processes. The implications of this phenomenon, its practical significance and possible use are discussed.
Bioluminescence is the production of light by living organisms. The luciferase genes responsible for the generation of light (lux genes) can be cloned from a bioluminescent microorganism into one that is not naturally bioluminescent. Light output can be monitored in real-time and will provide information on the metabolic state, location and quantity of cells in a given environment. Herein we review the applications of Lux-tagged microorganisms in the food industry including their uses in the development of novel food products and processes, for problem solving and for determining parameters important for the control of food quality and safety.
Many different approaches have been suggested for the assessment of organic pollution and
related water quality variables. However, many methods used to assess organic pollution
cannot qualitatively estimate the degree of importance of each pollutant. Water quality identification indices can provide comprehensive water quality information, which is both qualitative and quantitative, especially for areas worse than Grade V of the National Surface
Water Quality Standard of China. However, this method considers every indicator equally,
without considering the degree of importance of each parameter. Consequently, in this
study, the entropy weight method was combined with the water quality identification index
method. The improved comprehensive water quality identification index was applied to a
water quality data-set for the Wen-Rui Tang River in China, which was generated in 2009
during six months of monitoring at 16 different sites and included seven parameters. The
results indicated that the improved comprehensive water quality identification index provided an objective evaluation of each water quality indicator. Understanding the significance of each water quality parameter will help to implement more effective water quality
improvement plans
The paper considers mechanisms of detoxification of pollutant solutions by water-soluble humic substances (HSs), natural detoxifying agents. The problems and perspectives of bioassay application for toxicity monitoring of complex solutions are discussed from ecological point of view. Bioluminescence assays based on marine bacteria and their enzymes are of special attention here; they were shown to be convenient tools to study the detoxifying effects on cellular and biochemical levels. The advantages of bioluminescent enzymatic assay for monitoring both integral and oxidative toxicities in complex solutions of model pollutants and HS were demonstrated. The efficiencies of detoxification of the solutions of organic oxidizers and salts of metals (including radioactive ones) by HS were analyzed. The dependencies of detoxification efficiency on time of exposure to HS and HS concentrations were demonstrated. Antioxidant properties of HS were considered in detail. The detoxifying effects of HS were shown to be complex and regarded as 'external' (binding and redox processes in solutions outside the organisms) and/or 'internal' organismal processes. The paper demonstrates that the HS can stimulate a protective response of bacterial cells as a result of (1) changes of rates of biochemical reactions and (2) stabilization of mucous layers outside the cell walls. Acceleration of auto-oxidation of NADH, endogenous reducer, by HS was suggested as a reason for toxicity increase in the presence of HS due to abatement of reduction ability of intracellular media.
The objectives of the present work were to assess the use of moderate doses of gamma irradiation (2 to 5kGy) and to reduce the risk of pathogen presence without altering the quality attributes of bovine trimmings and of patties made of irradiated trimmings. Microbiological indicators (coliforms, Pseudomonas spp and mesophilic aerobic counts), physicochemical indicators (pH, color and tiobarbituric acid) and sensory changes were evaluated during storage. 5 kGy irradiation doses slightly increased off flavors in patties. Two pathogenic markers (Listeria monocytogenes and Escherichia coli O157:H7) were inoculated at high or low loads to trimming samples which were subsequently irradiated and lethality curves were obtained. Provided that using irradiation doses ≤2.5kGy are used, reductions of 2logCFU/g of L. monocytogenes and 5logCFU/g of E. coli O157:H7 are expected. It seems reasonable to suppose that irradiation can be successfully employed to improve the safety of frozen trimmings when initial pathogenic bacteria burdens are not extremely high.
Bacterial bioluminescence (BL) has been successfully applied in water-quality monitoring and in vivo imaging. The attention of researchers has been attracted for several decades, but the mechanism of bacterial BL is still largely unknown due to the complexity of the multistep reaction process. Debates mainly focus on three key questions: How is the bioluminophore produced? What is the exact chemical form of the bioluminophore? How does the protein environment affect the light emission? Using quantum mechanics (QM), combined QM and molecular mechanics (QM/MM) and molecular dynamic (MD) calculations in gas-phase, solvent and protein environments, the entire process of bacterial BL was investigated, from flavin reduction to light emission. This investigation revealed that: 1) the chemiluminescent decomposition of flavin peroxyhemiacetal does not occur through the intramolecular chemical initiated electron exchange luminescence (CIEEL) or the “dioxirane” mechanism, as suggested in the literature. Instead, the decomposition occurs according to the charge-transfer initiated luminescence (CTIL) mechanism for the thermolysis of dioxetanone. 2) The first excited state of 4a-hydroxy-4a,5-dihydroFMN (HFOH) was affirmed to be the bioluminophore of bacterial BL. This study provides details regarding the mechanism by which bacterial BL is produced and is helpful in understanding bacterial BL in general.
The recent accident at the Fukushima Daiichi Nuclear Power Plant caused by the Great East Japan Earthquake of March 11, 2012 reminded us vividly of the serious hazards of radioactive substances spread over a wide range of the affected region. Currently, there is a great concern over the effect of contaminated soil and water on the health and safety of the inhabitants of the region. Hence, the advancement in the technologies of nuclear waste treatment is of vital importance if we decide to live with nuclear power to maintain our modern civilization. Among various separation technologies used, membrane technologies have been chosen in this article since they are considered as one of the emerging technologies with many advantages over the conventional processes. In this review the membrane technology is classified into different processes and, for each process, progress made since the onset of this millennium in the radioactive decontamination of water is shown. The new directions are shown by considering the progress made in membrane manufacturing and membrane processes. Thus, the combined efforts of the researchers who are engaged in membrane and membrane process design with those who are engaged in nuclear waste treatment near the plant sites were highlighted.
Cadmium (Cd) compounds are widely distributed toxic environmental and industrial pollutants, and they may bring danger to growth and development of aquatic organisms. The effects of Ca(2+) (as CaCl2), Mg(2+) (as MgSO4), K(+) (as KCl), pH and complexants (EDTA, the commercial DOM, and three homemade DOMs) on Cd toxicity to Photobacterium phosphoreum were evaluated in standardized 15min acute toxicity tests. Increases in Ca(2+) concentration resulted in higher EC50 values, indicating the competition between the two ions for uptake sites at the biotic ligand. Increased waterborne Mg(2+) also reduced Cd toxicity, but to a slightly lesser degree compared with Ca(2+). The overall decline in EC50 data with increasing K(+) in test solutions suggested that Cd toxicity was enhanced at larger K(+) concentration. The toxicity alleviation by H(+) was observed over the tested pH range of 5.0-9.0. Additions of complexing agents into the exposure water reduced Cd bioavailability via complexation of Cd(2+), and complexants from different sources displayed different protective effect. The influence of these toxicity modifying factors was finally incorporated into a model that can predict acute cadmidum toxicity for Photobacterium phosphoreum. After validation with laboratory and natural waters, the developed model could support efforts to improve the ecological relevance of presently applied risk assessment procedures.
1. Oxygen is a toxic gas - an introductionto oxygen toxicity and reactive species 2. The chemistry of free radicals and related 'reactive species' 3. Antioxidant defences Endogenous and Diet Derived 4. Cellular responses to oxidative stress: adaptation, damage, repair, senescence and death 5. Measurement of reactive species 6. Reactive species can pose special problems needing special solutions. Some examples. 7. Reactive species can be useful some more examples 8. Reactive species can be poisonous: their role in toxicology 9. Reactive species and disease: fact, fiction or filibuster? 10. Ageing, nutrition, disease, and therapy: A role for antioxidants?
The purpose of this study was to investigate the potential of four different strains of white-rot fungi (Phanerochaete chrysosporium, Phanerochaete sordida, Phlebia brevispora, and Cyathus stercoreus) to degrade 2,4,6-trinitrotoluene (TNT) in liquid medium. Loss of TNT from the culture medium was determined using high-performance liquid chromatography (HPLC), while the mutagenicity of the medium residues were evaluated using the Salmonella/microsome bioassay. The data indicate that within 21 d of incubation, all fungi were able to reduce the TNT concentration in the liquid medium to below detection limits. In this study, P. sordida showed a relatively high growth rate and the fastest rate of TNT degradation. The fungal treatment also produced a significant reduction of TNT mutagenicity. Treatment with C. stercoreus, P. brevispora, P. sordida, and P. chrysosporium resulted in the elimination of 94%, 90%, 87%, and 67% of the initial TNT-amended medium mutagenicity, respectively. The data also demonstrate that during incubation, TNT was eliminated from the culture medium two to eight times faster than the reduction in mutagenic potential. These results suggest that TNT disappearance alone cannot be used as the sole criterion in TNT remediation. Chemical analysis revealed that the major metabolites in the initial transformation of TNT were the monoamino-dinitrotoluenes, which were also degraded by the selected white-rot fungi. The study demonstrated that the white-rot fungi are capable of metabolizing and detoxifying TNT under aerobic conditions in nonligninolytic liquid medium.
Intracellular accumulation of poly-3-hydroxybutyrate (PHB) was comparatively studied in the plant-growth-promoting bacterium (PGPB) Azospirillum brasilense (epiphytic strain Sp7 and endophytic strain Sp245) grown microaerobically for 2 days under nitrogen deficiency in the standard malate salt medium in the absence (control) or presence of copper (0.1mM Cu2+). For quantitative determination of PHB content of cells, diffuse reflectance infrared Fourier transform (DRIFT) spectroscopy of whole-cell biomass samples was used. After 2 days in control cells, PHB accumulation in strain Sp7 reached ca. 24% of dry cell mass (d.c.m.). In strain Sp245, the PHB content in the control was over 1.3-fold higher (32% d.c.m.) than in strain Sp7. In the presence of copper(II), PHB accumulation was notably enhanced in strain Sp7 (over 1.6-fold, up to ca. 39% d.c.m.), whereas in strain Sp245 it changed insignificantly (from 32% up to ca. 35% d.c.m.). The levels of copper(II) uptake were comparable in both strains. These findings are in line with our earlier observations that even in rich NH4+-supplemented medium, some heavy metals, including copper(II), induce PHB biosynthesis in A. brasilense strain Sp7, but not in Sp245. The dissimilarities in the levels of PHB accumulation and in the effects induced by copper(II) in the two strains are attributed to their different adaptive potentials owing to different ecological niches they occupy in the rhizosphere.
Abstract This article provides the first extensive documentation of mechanisms of hormetic dose/concentration responses. The mechanisms selected were principally those mediated via receptor and/or cell signaling pathways. Mechanisms are reported for greater than 100 agents affecting nearly 400 dose/concentration responses from a wide range of chemical classes, affecting a broad range of cell types and endpoints. Regardless of the model (i.e. in vitro or in vivo), inducing agent, endpoint, or receptor/cell signaling pathway mediated mechanism, the quantitative features of the hormetic dose/concentration responses are similar, suggesting that the magnitude of the response is a measure of biological plasticity, within a broad range of biological contexts. These findings represent an important advance in the understanding of the hormetic dose/concentration response, its generalizability and potential biomedical applications, including drug discovery/efficacy assessment and the risk assessment process.
The quenching of the fluorescence of excitation emission matrices (EEM) of two samples of dissolved organic matter (DOM) [fulvic acid from a dam water (FA) and a commercial humic acid (HA)], provoked by the metal ions Cu(II), UO22+, Fe(III) and Hg(II), was studied by principal component analysis (PCA) and multivariate curve resolution with alternating least squares (MCR-ALS). PCA of the individual EEM, sets of EEM and the sequential analysis of EEM allows the determination of the number of components that provoke linearly independent variations in the EEM and to assess the trend and stability of the quenching process. Four and three components were detected in the EEM of FA and HA, respectively. Some of these components show quenching in the presence of the studied metal ions and other are not affected. Also, the occurrence of scattering due to hydrolysis of metal ions is detected in the PCA sequential analysis of EEM as function of the metal ion concentration. Excitation and emission spectra and quenching profiles were extracted from EEM using MCR-ALS with non-negativity constraints. Stability constants between FA and HA with the studied metal ions were estimated by a modified Stern–Volmer equation.
Complexation of Am(III) with humic acid was studied at various pHs in 0.1M NaClO4. The stability constants of the Am(III)—humate complexes were determined by a cation-exchange method. The values of log1 and log2 increased slightly with increases of pH from 4 to 6 and were found to be 6.9 and 11.6, respectively, at a pH of 5. Markedly larger values than these were obtained by a solvent extraction method. This discrepancy was also revealed by summarizing data from several literature sources. It is very likely that this can be ascribed to decreases in either humic acid and/or the extractant from the extraction system due to humate interactions at the aqueous-organic interface.
Releases from the nuclear facility Mining-and-Chemical Combine (MCC) located at Zheleznogorsk have contributed to the radionuclide contamination of the Yenisei River since operations commenced in 1958. The aim of this study was to assess the activity concentrations of artificial radionuclides and the strength of their binding in Yenisei River sediments. Investigation of Yenisei River sediment samples revealed the presence of artificial radionuclides typical of the MCC radioactive discharge: namely, isotopes of europium, caesium, Co and transuranium elements. The concentrations of artificial radionuclides in the sediment layers remain relatively high as far as 200 km downstream of the MCC. In sediment cores collected upstream of the MCC, γ-spectrometric measurements registered only one artificial radionuclide, Cs, with a maximal activity of 8 Bq·kg. Sequential extraction performed on samples of the upper layers of the sediment core showed different degrees of potential environmental availability for artificial radionuclides: the highest was recorded for Am and Eu (up to 85% of initial activity), followed by Co (up to 32%), and finally, Cs (up to 15%). In a few samples, Am was present in the unextractable form, which may be accounted for by the presence of reactor fuel microparticles.
In this study, gamma irradiation sensitivities of bacteria and viruses in porcine skin were evaluated to establish the optimum sterilization condition for the dressing material and a xenoskin graft. Escherichia coli and Bacillus subtilis were used as model pathogens and inoculated at 106–107logCFU/g. As model viruses, porcine parvovirus (PPV), bovine viral diarrhea virus (BVDV), and poliovirus were used and inoculated at 105–106 TCID50/g into porcine skin. The D10 value of E. coli was found to be 0.25±0.1kGy. B. subtilis endospores produced under stressful environmental conditions showed lower radiation sensitivity as D10 was 3.88±0.3kGy in porcine skin. The D10 values of PPV, BVDV, and poliovirus were found to be 1.73±0.2, 3.81±0.2, and 6.88±0.3kGy, respectively. These results can offer the basic information required for inactivating pathogens by gamma irradiation and achieving dressing material and porcine skin grafts.
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Effect of UO2(NO3)2 on bioluminescent bacteria P.Phosphoreum was studied. It was compared with the effect of solutions of the more active radionuclide - 241Am(NO3)3 studied earlier (Rozhko et al., 2007). Bioluminescence inhibition was observed under uranyl concentrations exceeding 10-7 M (30 Bq/l); and bioluminescence activation was not observed under all radionuclide concentrations and exposure times in the experiment. Effect of uranyl was attributed to chemical component of its impact, not radiation one. It was shown that solutions of Americium were detoxified by humic substances (0.25 mg/ml), but solutions of uranyl – are not.
Several questions of importance in the study of lanthanide and actinide coordination compounds are revieed. There is considerable evidence that in aqueous solution the primary coordination number is nine for the ions La(m) through Nd(III) and eight for the ions heavier than Gd(III). hile it seems that some degree of covalency exists in the metal-ligand bonding a model of electrostatic bonding seems satisfactory for explaining the structure and formation of the complexes. The dehydration of the lanthanide ions upon complexation largely determines the enthalpy and entropy data. Hoever, there seems to be a compensation effect in the hydration parts of those terms such that the free energy changes seem to reflect the metal—ligand reaction unobscured by hydration factors. A number of individual inorganic and organic ligand systems are revieed from these viepoints.
The last 20 years have seen a major paradigm shift in radiation biology. Several discoveries challenge the DNA centric view which holds that DNA damage is the critical effect of radiation irrespective of dose. This theory leads to the assumption that dose and effect are simply linked - the more energy deposition, the more DNA damage and the greater the biological effect. This is embodied in radiation protection (RP) regulations as the linear-non-threshold (LNT) model. However the science underlying the LNT model is being challenged particularly in relation to the environment because it is now clear that at low doses of concern in RP, cells, tissues and organisms respond to radiation by inducing responses which are not readily predictable by dose. These include adaptive responses, bystander effects, genomic instability and low dose hypersensitivity, and are commonly described as stress responses, while recognizing that "stress" can be good as well as bad. The phenomena contribute to observed radiation responses and appear to be influenced by genetic, epigenetic and environmental factors, meaning that dose and response are not simply related. The question is whether our discovery of these phenomena means that we need to re-evaluate RP approaches. The so-called "non-targeted" mechanisms mean that low dose radiobiology is very complex and supra linear or sub-linear (even hormetic) responses are possible but their occurrence is unpredictable for any given system level. Issues which may need consideration are synergistic or antagonistic effects of other pollutants. RP, at present, only looks at radiation dose but the new (NTE) radiobiology means that chemical or physical agents, which interfere with tissue responses to low doses of radiation, could critically modulate the predicted risk. Similarly, the "health" of the organism could determine the effect of a given low dose by enabling or disabling a critical response. These issues will be discussed.
This article reviews a book which summarizes and classifies more than 1250 references to experimental work with low-level radiation between 1898 and 1977; explains that the detailed material is presented in tabular form with type of radiation as the primary classification and type of organism and date of report as subclassifications; notes that an incredible variety of effects are specified for flora and fauna; praises the summaries of background radiation and of overall radiation-dose effects to a variety of organisms; and emphasizes the importance of information dealing with the public perception of radiation and its effects.