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The mechanism of action of different types of antibiotics. Antibacterial action generally falls within one out of four mechanisms, three of which involve the inhibition or regulation of enzymes involved in cell wall biosynthesis, nucleic acid metabolism and repair, or protein synthesis, respectively. The fourth mechanism involves the disruption of membrane structure. Many of these cellular functions targeted by antibiotics are most active in multiplying cells.
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People have known the bacteria and have used various ways to deal with them, from a long time ago. Perhaps, natural antibiotics with have been the first step in fighting against pathogens. However, several factors, such as dealing with unfamiliar bacteria or emergence of drug-resistant species, have motivated us to discover new antibiotics or even...
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... example, the LytSR two-component system can affect cell lysis by regulating autolysin activity in Sta- differences of the highly conserved ribosomal proteins and RNAs in the variable regions among bacterial species (47). The action mechanism of different types of antibiotics is shown in Figure 2. ...
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Photodynamic inactivation of microorganisms has gained substantial attention due to its unique mode of action, in which pathogens are unable to generate resistance, and due to the fact that it can be applied in a minimally invasive manner. In photodynamic therapy (PDT), a non-toxic photosensitizer (PS) is activated by a specific wavelength of light...
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... 2 Antibiotics inhibit the synthesis of bacterial cells, proteins, ribonucleic acid and deoxyribonucleic acid through a membrane disorganizing agent. 3 Antibiotics also infiltrate the bacterial cell wall and are hooked up, via the energy-dependent mechanisms of transport in ribosomal sites, which subsequently inhibit the synthesis of the proteins (Fig. 1). 4 Resistance to antibiotics emerges quickly, making it a matter worthy of consideration as it is a burden to the health care system especially when new organisms are discovered. 5 Adhesion of bacteria leads to creation of biofilms on the surfaces of materials giving rise to economic and health problems (Fig. 2). ...
Antimicrobial resistance has proven to be an existential threat that endangers the health of human beings. The ease of accessing conventional antibiotics, and their unlimited and unregulated use and often misuse is seen to be a contributing factor to the rise in the resistance of microbes toward medications. The overuse of these medications in the agricultural sector also adds to the rising burden of antibiotic resistance. In line with efforts to counter the threat of antimicrobial resistance and the menace of hospital acquired infections developing antimicrobial surface coatings that can eliminate microbes that get deposited on those coatings is essential. This review aims to bring an understanding of antimicrobial resistance mechanisms, the preparation and mode of action and the future perspective of the antimicrobial surface coatings.
... Microbial metabolomics has been used in several microbiological fields, such as identification of microorganisms, [45] cellular mutations, research of functional genes [46] and identification of metabolic pathways [47]. Another important point is also the applicability of metabolites due to their bioactivities in various fields such as pharmacology, [48] agriculture, [49] cosmetology. But when compared to other studies, the main disadvantage of the microbial metabolomics studies is the high complexity of the samples and the presence of classes of metabolites that are still little explored. ...
Microorganisms are ubiquitous in diverse habitats and studying their chemical interactions with the environment and comprehend its complex relations with both hosts and environment, are crucial for the development of strategies to control microbial diseases. This chapter discusses the importance of studying microorganisms with agricultural benefits, using specialized metabolites as examples. Herein we highlight the challenges and opportunities in utilizing microorganisms as alternatives to synthetic pesticides and fertilizers in agriculture. Genome-guided investigations and improved analytical methodologies are necessary to characterize diverse and complex biomolecules produced by microorganisms. Predicting and isolating bioproducts based on genetic information have become a focus for researchers, aided by tools like antiSMASH, BiG-SCAPE, PRISM, and others. However, translating genomic data into practical applications can be complex. Therefore, integrating genomics, transcriptomics, and metabolomics enhances chemical characterization, aiding in discovering new metabolic pathways and specialized metabolites. Additionally, elicitation is one promising strategy to enhance beneficial metabolite production. Finally, identify and characterize microbial secondary metabolites remain challenging due to their low production, complex chemical structure characterization and different environmental factors necessary for metabolite in vitro production.
... 31 With its high chemical reactivity, singlet oxygen can interact with biological substrates, causing oxidative damage and ultimately resulting in bactericidal effects by disrupting cell membranes and cell walls. 32,33 The methods of aPDT involve the use of both Type I and Type II reactions, with the degree of potency depending on the concentration of PS and the oxygen environment. However, several factors have hindered the widespread adoption of aPDT in dentistry, such as the types and dosages of PS, light source, treatment time, tissue depth, oral environment, and more ( Fig. 2). ...
Oral infection is a common clinical symptom. While antibiotics are widely employed as the primary treatment for oral diseases, the emergence of drug-resistant bacteria has necessitated the exploration of alternative therapeutic approaches. One such modality is antimicrobial photodynamic therapy (aPDT), which utilizes light and photosensitizers. Indeed, aPDT has been used alone or in combination with other treatment options dealing with periodontal disease for the elimination of biofilms from bacterial community to achieve bone formation and/or tissue regeneration. In this review article, in addition to factors affecting the efficacy of aPDT, various photosensitizers, the latest technology and perspectives on aPDT are discussed in detail. More importantly, the article emphasizes the novel design and clinical applications of photosensitizers, as well as the synergistic effects of chemical and biomolecules with aPDT to achieve the complete eradication of biofilms and even enhance the biological performance of tissues surrounding the treated oral area.
... 8 Some targets of antibacterial drugs are affecting the biosynthesis of bacterial cell walls, biosynthesis of bacterial proteins, destroying bacterial cells, and replicating bacterial DNA. 9 The test bacteria that represent the conditions of ownership of grampositive and negative are Staphylococcus aureus and Escherichia coli, respectively. 10 In bacteria S. aureus has TyrRS protein which is used in catalyzing tyrosine in ATP formation and C30 protein which produces aureus pigment in reducing survival under oxidative stress conditions. ...
Pinus merkusii is empirically used as an antibacterial agent and has been found to have secondary metabolites such as alkaloids, terpenoids, and flavonoids. This study aims to investigate the antibacterial effects of pine flower extract on gram-positive and gram-negative bacteria. In addition, molecular docking and molecular dynamics simulations were used to understand the underlying mechanism of its antibacterial activity. The antibacterial screening was performed using the disc diffusion method, compound analysis in the extract was carried
out using Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS), molecular docking was performed using Autodock Vina integrated into PyRx, and molecular dynamics simulation was run using YASARA Dynamics. The antibacterial test results showed that the pine flower extract had the highest inhibitory effect on Escherichia coli(1.038 ± 0.169 mm) and Staphylococcus aureus (7.154 ± 0.381 mm). Compound analysis of the pine flower extract showed the presence of Myricetin, Epicatechin, Nepetin, Hispidulin, Kaempferol, Luteolin-7-O�rutinoside, and Hesperidin. The molecular docking and molecular dynamics simulation results
showed that Epicatechin, Nepetin, and Luteolin-7-O-rutinoside compounds could inhibit bacterial cell wall formation proteins.
... e interaction of selected antibiotic DC after adsorption has shifted the peak positions for both the adsorbents as shown in Figures 2(c) and 2(d) indicated the positive interactions between the adsorbent and adsorbate. In our previous publications, although such shifting was observed, here, the interaction is more favorable that has resulted in high adsorption capacity and consequently better effects on foul control in the membrane processes [20][21][22]. e interactions between adsorbent functional groups and those of adsorbate play an important role in the reclamation of a given pollutant from an aqueous environment. When there is shifting of many functional group peaks after adsorption of a given pollutant, the interactions are considered more favorable in comparison to a system where the shifting is not drastic. ...
The carbonaceous adsorbents, an activated carbon (AC) and a bioinorganic nanocomposite (MAC), were prepared using Dalbergia sissoo sawdust as waste biomass, in this study. Both the adsorbents were characterized by FTIR, EDX, SEM, XRD, TG/DTA, surface area, and a pore size analyzer. The adsorbents were used for the removal of an antibiotic, doxycycline (DC) antibiotic, from wastewater in order to minimize a load of antibiotics in industrial effluents and consequently the drug resistance problem. Initially, the effectiveness of adsorbent was confirmed using batch adsorption experiments where isothermal models like Langmuir, Freundlich Temkin, Jovanovic, and Harkins–Jura were utilized to govern the maximum adsorption capacity of AC and MAC while pseudo-first- and second-order kinetic models were used to estimate the values of different kinetic parameters. Langmuir model best accommodated the equilibrium data whereas the pseudo-second-order kinetic model finest trimmed the kinetics data. The effect of pH on adsorption was also evaluated where maximum removal was observed between pH 5 and 7 by both adsorbents. The effect of temperature on adsorption was evaluated where the entropy change (ΔS⁰) comes out to have a numerically positive value whereas Gibbs free energy change (ΔG⁰) and enthalpy change (ΔH⁰) were negative indicating the spontaneous nature and feasibility of the procedure. The robust technology of membrane separation is rapidly replacing the conventional technologies but at the same time suffers from the problem of membrane fouling. As pretreatment, the AC and MAC were used in hybrid with ultrafiltration (UF), nanofiltration (NF), and reverse osmosis (RO) membranes whereas permeate fluxes and percent retention of DC were compared for naked membrane operations and AC/membrane and MAC/membrane process. The permeate fluxes for MAC/membrane processes were greater as compared to AC/membrane and naked membrane processes showing the effectiveness of the bioinorganic composite as foul control and consequently recovery of DC from effluents. The percent retention of the UF membrane was lower as compared to NF and RO membranes. Improvement in percent retention for UF/AC, UF/MAC, NF/AC, NF/MAC, RO/AC, and RO/MAC was observed. The bioinorganic composite MAC contains a magnetic iron oxide which was effectively removed from slurry after use through the magnetic process and that was the main reason for high permeate fluxes in MAC/membrane operations.
... On the other side, infectious diseases have also been one of the leading causes of death in humans [13]. From the 19th century onwards, antimicrobial agents have been developed extensively, and more potential antibiotics have been identified one after another [14,15]. During these years, the development of antimicrobial agents to obtain antibiotics with a wider range and stronger activity has been continued [16,17]. ...
Despite the promising medicinal properties, berberine (BBR), due to its relatively poor solubility in plasma, low bio-stability and limited bioavailability is not used broadly in clinical stages. Due to these drawbacks, drug delivery systems (DDSs) based on nanoscale natural polysaccharides, are applied to address these concerns. Natural polymers are biodegradable, non-immunogenic, biocompatible, and non-toxic agents that are capable of trapping large amounts of hydrophobic compounds in relatively small volumes. The use of nanoscale natural polysaccharide improves the stability and pharmacokinetics of the small molecules and, consequently, increases the therapeutic effects and reduces the side effects of the small molecules. Therefore, this paper presents an overview of the different methods used for increasing the BBR solubility and bioavailability. Afterwards, the pharmacodynamic and pharmacokinetic of BBR nanostructures were discussed followed by the introduction of natural polysaccharides of plant (cyclodextrines, glucomannan), the shells of crustaceans (chitosan), and the cell wall of brown marine algae (alginate)-based origins used to improve the dissolution rate of poorly soluble BBR and their anticancer and antibacterial properties. Finally, the anticancer and antibacterial mechanisms of free BBR and BBR nanostructures were surveyed. In conclusion, this review may pave the way for providing some useful data in the development of BBR-based platforms for clinical applications.
... Photodynamic therapy (PDT) is a versatile therapeutic technique that has been successfully applied throughout the years in cancer treatment [1][2][3][4][5], aged related macular degeneration [3,6] and in the inactivation of microorganisms (antimicrobial PDT = aPDT) under clinical and non-clinical contexts [7][8][9][10]. More recently, the possibility of exploring the approach for improving wound healing/tissue regeneration after a traumatic lesion is attracting the attention of several research groups [11][12][13][14][15]. ...
The concept behind photodynamic therapy (PDT) is being successfully applied in different biomedical contexts such as cancer diseases, inactivation of microorganisms and, more recently, to improve wound healing and tissue regeneration. The effectiveness of PDT in skin treatments is associated with the role of reactive oxygen species (ROS) produced by a photosensitizer (PS), which acts as a "double agent". The release of ROS must be high enough to prevent microbial growth and, simultaneously, to accelerate the immune system response by recruiting important regenerative agents to the wound site. The growing interest in this subject is reflected by the increasing number of studies concerning the optimization of relevant experimental parameters for wound healing via PDT, namely, light features, the structure and concentration of the PS, and the wound type and location. Considering the importance of developing PSs with suitable features for this emergent topic concerning skin wound healing, in this review, a special focus on the achievements attained for each PS class, namely, of the non-porphyrinoid type, is given.
... Photosensitizers have poor selectivity towards pathogens and also lead to the occurrence of resistant bacteria. In addition, the short excitation light wave of photosensitizers has poor penetrating power [116,119,120]. By contrast, endolysins do not produce resistant bacteria due to the importance and conservation of their targets, peptidoglycan layer, for the viability of bacteria and they also obtain access to pathogens in inner tissues and organs in vivo [112]. ...
Antimicrobial resistance (AMR) is a global crisis for human public health which threatens the effective prevention and control of ever-increasing infectious diseases. The advent of pandrug-resistant bacteria makes most, if not all, available antibiotics invalid. Meanwhile, the pipeline of novel antibiotics development stagnates, which prompts scientists and pharmacists to develop unconventional antimicrobials. Bacteriophage-derived endolysins are cell wall hydrolases which could hydrolyze the peptidoglycan layer from within and outside of bacterial pathogens. With high specificity, rapid action, high efficiency, and low risk of resistance development, endolysins are believed to be among the best alternative therapeutic agents to treat multidrug resistant (MDR) bacteria. As of now, endolysins have been applied to diverse aspects. In this review, we comprehensively introduce the structures and activities of endolysins and summarize the latest application progress of recombinant endolysins in the fields of medical treatment, pathogen diagnosis, food safety, and agriculture.
... This may lead to limiting the therapeutic efficacy of a single antibiotic (6). To overcome the shortcomings of antibiotics, photodynamic therapy (PDT) has been developed as a promising alternative to treat bacterial infections with broadspectrum and multitarget features (7,8). ...
Bacterial infections are common diseases causing tremendous deaths in clinical settings. It has been a big challenge to human beings because of the antibiotics abuse and the newly emerging microbes. Photodynamic therapy (PDT) is a reactive oxygen species-based therapeutic technique through light-activated photosensitizer (PS). Recent studies have highlighted the potential of PDT as an alternative method of antibacterial treatment for its broad applicability and high efficiency. However, there are some shortcomings due to the low selectivity and specificity of PS. Growing evidence has shown that drug delivery nanoplatforms have unique advantages in enhancing therapeutic efficacy of drugs. Particularly, stimuli-responsive nanoplatforms, as a promising delivery system, provide great opportunities for the effective delivery of PS. In the present mini-review, we briefly introduced the unique microenvironment in bacterial infection tissues and the application of PDT on bacterial infections. Then we review the stimuli-responsive nanoplatforms (including pH-, enzymes-, redox-, magnetic-, and electric-) used in PDT against bacterial infections. Lastly, some perspectives have also been proposed to further promote the future developments of antibacterial PDT.
... ROS produced by PS membrane attachment inactivates the membrane transport system and associated enzymes, thereby inducing lipid peroxidation, which damages the cell membrane structure [32,33]. Esmatabadi et al. reported that after PDI-mediated cell membrane destruction, cytoplasm contents and metabolites were released from cells, and DNA was damaged [34]. In this study, we observed the destruction and cytoplasmic release of S. mutans cell membranes via the PDI treatment of FFF. ...
The objective of this study was to determine reactive oxygen species (ROS) produced by fagopyrin F-rich fraction (FFF) separated from Tartary buckwheat flower extract exposed to lights and to investigate its antibacterial photodynamic inactivation (PDI) against Streptococcus mutans and its biofilm. ROS producing mechanisms involving FFF with light exposure were determined using a spectrophotometer and a fluorometer. S. mutans and its biofilm inactivation after PDI treatment of FFF using blue light (BL; 450 nm) were determined by plate count method and crystal violet assay, respectively. The biofilm destruction by ROS produced from FFF after exposure to BL was visualized using confocal laser scanning microscopy (CLSM) and field emission scanning electron microscope (FE-SEM). BL among 3 light sources produced type 1 ROS the most when applying FFF as a photosensitizer. FFF exposed to BL (5 and 10 J/cm2) significantly more inhibited S. mutans viability and biofilm formation than FFF without the light exposure (p < 0.05). In the PDI of FFF exposed to BL (10 J/cm2), an apparent destruction of S. mutans and its biofilm were observed by the CLSM and FE-SEM. Antibacterial PDI effect of FFF was determined for the first time in this study.
