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Numbers of planktonic E. coli cells in vials containing 8 g of glass beads with diameters of 0.5 mm, 1.0 mm, and 2.5 mm and vials without glass beads, in PBS and PBS with Tween 80. Error bars depict ±1 standard deviation (n = 20).
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Bacterial adhesion to natural and man-made surfaces can be beneficial or detrimental, depending on the system at hand. Of vital importance is how the process of adhesion affects the bacterial metabolic activity. If activity is enhanced, this may help the cells colonize the surface, whereas if activity is reduced, it may inhibit colonization. Here,...
Citations
... In the planktonic cell recovery studies, this justified why BAC-killed cells upon recovery showed higher PI uptake percentages than DBNPA despite the TEM micrographs showed apparently intact cell membranes in the latter case (Barros et al. [5]). Also, the much higher ATP content of DBNPA cells' recovery comparing to BAC ones seems to be associated with the inhibition of high energy-consuming processes by the DBPNA mechanism of action, which favours the accumulation of ATP in cells [26,27]. ...
... For example, the PI uptake for BAC-killed cells biofilms is higher than the one observed for biofilms formed from DBNPA-killed ones, suggesting that there is a significant amount of cells with injured membranes in the biofilm (allowing the PI to penetrate and stain the cells' membrane). Another example is the higher ATP levels observed for DBNPA-dead cells comparing to BAC ones, which is possibly linked to the ability that cells exposed to DBNPA have to enter the VBNC state and accumulate ATP [26,27]. These results suggest that damaged cells are a significant part of the biofilm even after 5 days. ...
... Another aspect that stands out in the present work is that dead cells contribute to different extents to the biofilm development-significantly higher thicknesses were found for biofilms from DBNPA-killed cells rather than BAC ones. Indeed, the increased thickness of DBNPA biofilms is arguably another consequence of the accumulation of ATP inside the DBNPA-exposed cells [26,27]. Increased ATP reserves allow cells inside the biofilm to recover more quickly, contributing to the higher thickness of biofilms from DBPNA-dead cells. ...
Industrial biocides aim to keep water systems microbiologically controlled and to minimize biofouling. However, the resulting dead cells are usually not removed from the water streams and can influence the growth of the remaining live cells in planktonic and sessile states. This study aims to understand the effect of dead Pseudomonas fluorescens cells killed by industrial biocides—benzalkonium chloride (BAC) and 2,2-dibromo-3-nitrilopropionamide (DBNPA)—on biofilm formation. Additionally, the effect of different dead/live cell ratios (50.00% and 99.99%) was studied. The inoculum was recirculated in a Parallel Plate Flow Cell (PPFC). The overall results indicate that dead cells greatly affect biofilm properties. Inoculum with DBNPA–dead cells led to more active (higher ATP content and metabolic activity) and thicker biofilm layers in comparison to BAC–dead cells, which seems to be linked to the mechanism of action by which the cells were killed. Furthermore, higher dead cell ratios (99.99%) in the inoculum led to more active (higher culturability, metabolic activity and ATP content) and cohesive/compact and uniformly distributed biofilms in comparison with the 50.00% dead cell ratio. The design of future disinfection strategies must consider the contribution of dead cells to the biofilm build-up, as they might negatively affect water system operations.
... Furthermore, an optimum pH of 7, which was observed during HAB soy meal protein fermentation, can be understood from the perspective of cellular energetics. Bacteria can effectively modulate proton and ATP production levels by leveraging the interplay between cellular bioenergetics (electrochemical proton gradient and ATP synthesis) and the physiochemical charge regulation effect that occurs on cell surfaces [63]. Studies have shown that cellular pH has a significant impact on cellular processes, including microbial growth for optimal energy generation [64,65]. ...
Background:
Conventional ammonia production methods, notably the energy-intensive Haber-Bosch process, are costly and contribute substantially to about 2% of the world's CO2 emissions. This study focuses on the biological approach to convert protein to ammonia via hyper-ammonia-producing bacteria (HAB) fermentation.
Methods:
A consortium of ruminal microbes was employed in this work to ferment soybean meal protein under varying processing conditions. The parameters investigated included pH (7-11), inoculum concentrations (1-10%), substrate concentrations (5-20%), and fermentation time (0-168 h).
Results:
Optimal conditions for microbial growth and biological ammonia production were observed at pH 7, fermentation duration of 72 h, inoculum concentration of 10%, and substrate concentration of 10%. ~8000 mg/L biological ammonia was produced following HAB fermentation.
Conclusions:
By leveraging the capabilities of rumen HAB, this study contributes to the ongoing efforts to develop environmentally friendly processes for ammonia production that will mitigate both economic and environmental concerns associated with traditional methods.
... Previous studies have shown that Bacillus species and E. coli have a similar ATP content at a physiological pH [46,47], but one study showed that the efficacy of ATP-based microbial detection methods is limited for Gram-negative bacteria because cell lysis is incomplete [48]. The detection sensitivity for the proposed system will be increased in the future using better cell lysis methods, such as the addition of lysozymes or the use of more efficient lysis buffers. ...
... To investigate the feasibility of the ATP-sensing chip in practical applications, the amount of ATP in the spiked field samples of tap water and ground-harvested rainwater was measured and compared with that in the spiked ATP-binding buffer. As shown in Figure 9a,b, the photocurrent production of the pristine b-PM chip and the ATP-aptamercoated chip both notably reduce to constant levels after incubation in tap water and rain- Previous studies have shown that Bacillus species and E. coli have a similar ATP content at a physiological pH [46,47], but one study showed that the efficacy of ATP-based microbial detection methods is limited for Gram-negative bacteria because cell lysis is incomplete [48]. The detection sensitivity for the proposed system will be increased in the future using better cell lysis methods, such as the addition of lysozymes or the use of more efficient lysis buffers. ...
A uniformly oriented purple membrane (PM) monolayer containing photoactive bacteriorhodopsin has recently been applied as a sensitive photoelectric transducer to assay color proteins and microbes quantitatively. This study extends its application to detecting small molecules, using adenosine triphosphate (ATP) as an example. A reverse detection method is used, which employs AuNPs labeling and specific DNA strand displacement. A PM monolayer-coated electrode is first covalently conjugated with an ATP-specific nucleic acid aptamer and then hybridized with another gold nanoparticle-labeled nucleic acid strand with a sequence that is partially complementary to the ATP aptamer, in order to significantly minimize the photocurrent that is generated by the PM. The resulting ATP-sensing chip restores its photocurrent production in the presence of ATP, and the photocurrent recovers more effectively as the ATP concentration increases. Direct and single-step ATP detection is achieved in 15 min, with detection limits of 5 nM and a dynamic range of 5 nM–0.1 mM. The sensing chip exhibits high selectivity against other ATP analogs and is satisfactorily stable in storage. The ATP-sensing chip is used to assay bacterial populations and achieves a detection limit for Bacillus subtilis and Escherichia coli of 102 and 103 CFU/mL, respectively. The demonstration shows that a variety of small molecules can be simultaneously quantified using PM-based biosensors.
... 12 This ability of swimming cells to distinguish coating mechanics may require close cell approach to a surface, but it is unclear whether the cell body or the flagella is responsible. Because restrictions in flagellar rotation trigger the upregulation of virulence factors, [13][14][15][16] because exposure of the cell envelope to interfacial physico-chemistry can initiate separate virulence pathways, [17][18][19][20] and because surface mechanics influence the frequency and duration of cellsurface encounters, 12,21,22 it becomes important to understand the extent of surface contact for swimming and flowing bacteria. These close interactions may allow material chemistry and mechanical interactions to produce a population of surface-altered cells of increased virulence even before arrest occurs. ...
Bacteria are keenly sensitive to properties of the surfaces they contact, regulating their ability to form biofilms and initiate infections. This study examines how the presence of flagella, interactions between the cell body and the surface, or motility itself guides the dynamic contact between bacterial cells and a surface in flow, potentially enabling cells to sense physicochemical and mechanical properties of surfaces. This work focuses on a poly(ethylene glycol) biomaterial coating, which does not retain cells. In a comparison of four Escherichia coli strains with different flagellar expressions and motilities, cells with substantial run-and-tumble swimming motility exhibited increased flux to the interface (3 times the calculated transport-limited rate which adequately described the non-motile cells), greater proportions of cells engaging in dynamic nanometer-scale surface associations, extended times of contact with the surface, increased probability of return to the surface after escape and, as evidenced by slow velocities during near-surface travel, closer cellular approach. All these metrics, reported here as distributions of cell populations, point to a greater ability of motile cells, compared with nonmotile cells, to interact more closely, forcefully, and for greater periods of time with interfaces in flow. With contact durations of individual cells exceeding 10 s in the window of observation and trends suggesting further interactions beyond the field of view, the dynamic contact of individual cells may approach the minute timescales reported for mechanosensing and other cell recognition pathways. Thus, despite cell translation and the dynamic nature of contact, flow past a surface, even one rendered non-cell arresting by use of an engineered coating, may produce a subpopulation of cells already upregulating virulence factors before they arrest on a downstream surface and formally initiate biofilm formation.
... However, strategies assisting bacteria to resist the low pH 3 29 do not permit the release of the electrons and protons (H + ) produced in the respiratory chain, inhibiting dye reduction. This is due to the intricate correlation between the proton motive force (PMF) and ATP, namely the link between cellular bioenergetics and the charge regulation effect, which occurs at the surface of the cell 35 . An observation worth mentioning is that the adsorbed dye at pH 3 was not desorbed during the cell washing with water or normal saline (namely, an irreversible adsorption between dye and cells in aqueous medium) but dye was desorbed in ethanol during the dehydration step in the glutaraldehyde fixation procedure. ...
Introduction: Biodegradation of azo dyes under harsh environmental conditions has been of great interest for the treatment of colored effluents. The present study aims to evaluate Klebsiella quasipneumoniae GT7 for degrading azo dye Carmoisine under extreme pH conditions and high salinity.
Materials and Methods: The growth profiles of bacteria were compared under different conditions of salinity and pH, using the optical density and viability measurements. Kinetic patterns of decolourization by GT7 were investigated under different concentrations of NaCl and/or pH, through the spectrophotometry method. Moreover, thin layer chromatography (TLC) was used to evaluate the biotransformation of Carmoisine into aromatic amines. Scanning electron microscopy (SEM) was carried out to analyze any morphological changes in bacteria under stress conditions.
Results: GT7 showed OD-based growth and sustainable viability under [NaCl] ≤ 15% and/or initial pH between 3-11. The viable but nonculturable (VBNC) state explained the bacteria's survival under attenuated growth due to bacterial inefficiency to maintain cytoplasmic osmotic balance, vital turgor pressure, and pH homeostasis. Biodecolourization was accomplished during 48h, where Carmoisine was 50mg/l, [NaCl] ≤ 20%, and/or initial was pH 5-11. TLC, OD600nm and pH measurements as well as visual observation of bacterial pellets at the end of the decolourization confirmed biodegradation as the dominant mechanism, except for pH 3, where dye was removed via adsorption to the cell surface. SEM showed morphological alteration of GT7 from rod to coccoid shape as an approach to resist the harsh conditions ratio.
Conclusion: GT7 is shown as an efficient strain for azo dye degradation in harsh environmental conditions.
... Likewise, the liberation of ATP has to be entertained when considering metabolism or viability, as a considerable portion of the ATP in a culture can be extracellular, particularly in the exponential growth stage or when exposed to antimicrobial agents [49]. Accordingly, ATP values have to be handled with respect, notably as their usage is still argued for some applications. ...
... ATP is misplaced, and many biochemical reactions, including the action of ATPases, speedily reduce any residual ATP from the cytoplasm [48]. Likewise, the liberation of ATP has to be entertained when considering metabolism or viability, as a considerable portion of the ATP in a culture can be extracellular, particularly in the exponential growth stage or when exposed to antimicrobial agents [49]. Accordingly, ATP values have to be handled with respect, notably as their usage is still argued for some applications. ...
Novel 1,3,4-thiadiazole derivatives were synthesized through the reaction of methyl 2-(4-hydroxy-3-methoxybenzylidene) hydrazine-1-carbodithioate and the appropriate hydrazonoyl halides in the presence of a few drops of diisopropylethylamine. The chemical structure of the newly fabricated compounds was inferred from their microanalytical and spectral data. With the increase in microbial diseases, fungi remain a devastating threat to human health because of the resistance of microorganisms to antifungal drugs. COVID-19-associated pulmonary aspergillosis (CAPA) and COVID-19-associated mucormycosis (CAM) have higher mortality rates in many populations. The present study aimed to find new antifungal agents using the disc diffusion method, and minimal inhibitory concentration (MIC) values were estimated by the microdilution assay. An in vitro experiment of six synthesized chemical compounds exhibited antifungal activity against Rhizopus oryzae; compounds with an imidazole moiety, such as the compound 7, were documented to have energetic antibacterial, antifungal properties. As a result of these findings, this research suggests that the synthesized compounds could be an excellent choice for controlling black fungus diseases. Furthermore, a molecular docking study was achieved on the synthesized compounds, of which compounds 2, 6, and 7 showed the best interactions with the selected protein targets. View Full-Text
... This difference in the consumption of protons between the treatment with HA and DNP might be due to their chemical nature. Previous studies have demonstrated that a change in pH across the cell membrane of only 0.2 units is sufficient to achieve variations in proton motive force [39]. The HA may affect the proton motive force generation, which is closely related to flagellum functionality, which could explain the observed effects in mobility. ...
Extracts of Hibiscus sabdariffa L. (commonly called Rosselle or “Jamaica flower” in Mexico) have been shown to have antibiotic and antivirulence properties in several bacteria. Here, an organic extract of H. sabdariffa L. is shown to inhibit motility in Salmonella enterica serovars Typhi and Typhimurium. The compound responsible for this effect was purified and found to be the hibiscus acid. When tested, this compound also inhibited motility and reduced the secretion of both flagellin and type III secretion effectors. Purified hibiscus acid was not toxic in tissue-cultured eukaryotic cells, and it was able to reduce the invasion of Salmonella Typhimurium in epithelial cells. Initial steps to understand its mode of action showed it might affect membrane proton balance.
... A higher abundance of a molecule involved with energy production in the diseased groups was not surprising considering the high bacterial load and microbial biofilm formation in periodontal disease. The relationship between bacterial adhesion, which is a required first stage during biofilm formation, and ATP levels has been previously described 36 . Indeed, enhanced metabolic activity was observed when Escherichia coli and Bacillus brevis adhered onto a surface, with ATP levels increasing up to five-fold upon adhesion compared to ATP levels in planktonic cells 36 , suggesting that increased metabolic activity may help cells colonize surfaces and that decreased metabolic activity may promote cell inactivation or death 36 . ...
... The relationship between bacterial adhesion, which is a required first stage during biofilm formation, and ATP levels has been previously described 36 . Indeed, enhanced metabolic activity was observed when Escherichia coli and Bacillus brevis adhered onto a surface, with ATP levels increasing up to five-fold upon adhesion compared to ATP levels in planktonic cells 36 , suggesting that increased metabolic activity may help cells colonize surfaces and that decreased metabolic activity may promote cell inactivation or death 36 . ...
... The relationship between bacterial adhesion, which is a required first stage during biofilm formation, and ATP levels has been previously described 36 . Indeed, enhanced metabolic activity was observed when Escherichia coli and Bacillus brevis adhered onto a surface, with ATP levels increasing up to five-fold upon adhesion compared to ATP levels in planktonic cells 36 , suggesting that increased metabolic activity may help cells colonize surfaces and that decreased metabolic activity may promote cell inactivation or death 36 . ...
The subgingival microbial communities of domestic cats remain incompletely characterized and it is unknown whether their functional profiles are associated with disease. In this study, we used a shotgun metagenomic approach to explore the functional potential of subgingival microbial communities in client-owned cats, comparing findings between periodontally healthy cats and cats with naturally occurring chronic periodontitis, aggressive periodontitis, and feline chronic gingivostomatitis. Subgingival samples were subjected to shotgun sequencing and the metagenomic datasets were analyzed using the MG-RAST metagenomic analysis server and STAMP v2.1.3 (Statistical Analysis of Metagenomic Profiles) software. The microbial composition was also described to better understand the predicted features of the communities. The Respiration category in the level 1 Subsystems database varied significantly among groups. In this category, the abundance of V-Type ATP-synthase and Biogenesis of cytochrome c oxidases were significantly enriched in the diseased and in the healthy groups, respectively. Both features have been previously described in periodontal studies in people and are in consonance with the microbial composition of feline subgingival sites. In addition, the narH (nitrate reductase) gene frequency, identified using the KEGG Orthology database, was significantly increased in the healthy group. The results of this study provide preliminary functional insights of the microbial communities associated with periodontitis in domestic cats and suggest that the ATP-synthase and nitrate-nitrite-NO pathways may represent appropriate targets for the treatment of this common disease.
... During the early stages of biofilm formation, bacterial cells are known to be affected by electrochemical forces associated with the substrate and once adhered, they undergo physiological changes in gene and protein expression as well as morphology [33]. In addition, the metabolic state of the bacteria may change, with enhanced expression of glycolytic enzymes and increased ATP production [34,35]. Studies on Escherichia coli have shown that the pH close to the surface may be lower than that of the surrounding liquid suggesting that local adaptation to a low pH environment may also contribute to an increase in acid tolerance [36]. ...
Abstract Background In caries, low pH drives selection and enrichment of acidogenic and aciduric bacteria in oral biofilms, and development of acid tolerance in early colonizers is thought to play a key role in this shift. Since previous studies have focussed on planktonic cells, the effect of biofilm growth as well as the role of a salivary pellicle on this process is largely unknown. We explored acid tolerance and acid tolerance response (ATR) induction in biofilm cells of both clinical and laboratory strains of three oral streptococcal species (Streptococcus gordonii, Streptococcus oralis and Streptococcus mutans) as well as two oral species of Actinomyces (A. naeslundii and A. odontolyticus) and examined the role of salivary proteins in acid tolerance development. Methods Biofilms were formed on surfaces in Ibidi® mini flow cells with or without a coating of salivary proteins and acid tolerance assessed by exposing them to a challenge known to kill non-acid tolerant cells (pH 3.5 for 30 min) followed by staining with LIVE/DEAD BacLight and confocal scanning laser microscopy. The ability to induce an ATR was assessed by exposing the biofilms to an adaptation pH (pH 5.5) for 2 hours prior to the low pH challenge. Results Biofilm formation significantly increased acid tolerance in all the clinical streptococcal strains (P
... Differences in the microenvironmental pH between surface-associated and planktonic cells lead to differences in metabolic activity. For instance, a pH change of only 0.2-0.5 units across the bacterial cell membrane caused by the cell-mineral interface may result in ATP levels 2-5 times higher than those of planktonic cells (Hong and Brown, 2009). Although there is a significant difference in the specific surface areas (SSAs) of the minerals used in the experiments (Table EA2), the difference is not equivalent to the difference in the area that can be used for the attachment of the T. flavus hyphae. ...
Fungus-mineral interactions influence a variety of geochemical and biological processes on and near the Earth’s surface. The secondary metabolites produced by fungi during these interactions control mineral weathering and affect geochemical element cycling; however, the extent to which minerals exert their influence on fungal metabolism has not been quantitatively determined in detail. Here, we used mass spectroscopy to investigate the exometabolome of Talaromyces flavus, a serpentine soil-inhabiting fungus, during interactions with antigorite, chlorite, hornblende, lizardite, magnetite, and quartz at 28 °C under aerobic conditions. Our experimental results showed that all the minerals used promoted spore germination and hyphal growth. The glucose consumption rate during the initial stages of the fungus-mineral interactions indicated that the metabolic activity of T. flavus was enhanced by a factor of ∼7 by lizardite, antigorite, chlorite, hornblende, and magnetite and by a factor of ∼3 by quartz. A total of 1198 secondary metabolites were detected at 166 h, and 977 (81.55%) of them were common to the T. flavus interactions with antigorite, chlorite, hornblende, lizardite, and magnetite. Statistical and comparative analyses of the 28 most common organic acids revealed that the production of these secondary metabolites by T. flavus was highly mineral-specific and that their content varied significantly in response to the different minerals. Moreover, the component composition of the secondary metabolites of T. flavus interacting with lizardite was more similar to chlorite and magnetite than to antigorite, hornblende, and quartz. Strong correlations were found between the production of gluconic, oxalic, citric, and itaconic acid and the bioavailability of certain elements. Fumaric and orsellinic acid production were stimulated by magnetite and chlorite, respectively. These results demonstrate that fungi can significantly regulate their metabolic behavior during interactions with minerals and that their metabolic regulation is primarily related to the chemical composition, weatherability, and surface properties of the minerals. Such biotic and abiotic responses have important implications for the fungus-induced geochemical transformation of minerals and metals.
