# | Rank | Similarity | Title + Abs. | Year | PMID |
|---|---|---|---|---|---|
| 0 | 1 | 2 | 3 | 4 | 5 |
| 9109 | 0 | 1.0000 | Insights from the Molecular dynamics simulation of BcsD Subunit from K. xylinus. Biofilms are bacteria living in micro-colonies with a protective coating in sessile form. The biofilm protects bacteria from harsh surroundings as well as help in antibiotics resistance using a semi-fluid substance. Cellulose is the major component of biofilm, which provides the sticky appearance to bacteria for attaching to the substratum. The bacteria communicate in biofilm with the help of quorum sensing hormones Acylated Homoserine Lactones (AHL's). In Komagataeibacter xylinus the four genes Bcs A, Bcs B, Bcs C, Bcs D are associated with cellulose biosynthesis. The Bcs D subunits have a hypothetical octamer pore-like structure through which glucan molecule pass to form the cellulose. Therefore, it is of interest to document a structural understanding of Bcs D. Hence a homology model of Bcs D was simulated and analyzed further to gain functional insight towards biofilm formation. | 2017 | 29225430 |
| 9427 | 1 | 0.9993 | Polysaccharides' Structures and Functions in Biofilm Architecture of Antimicrobial-Resistant (AMR) Pathogens. Bacteria and fungi have developed resistance to the existing therapies such as antibiotics and antifungal drugs, and multiple mechanisms are mediating this resistance. Among these, the formation of an extracellular matrix embedding different bacterial cells, called biofilm, is an effective strategy through which bacterial and fungal cells are establishing a relationship in a unique environment. The biofilm provides them the possibility to transfer genes conferring resistance, to prevent them from desiccation and to impede the penetration of antibiotics or antifungal drugs. Biofilms are formed of several constituents including extracellular DNA, proteins and polysaccharides. Depending on the bacteria, different polysaccharides form the biofilm matrix in different microorganisms, some of them involved in the first stage of cells' attachment to surfaces and to each other, and some responsible for giving the biofilm structure resistance and stability. In this review, we describe the structure and the role of different polysaccharides in bacterial and fungal biofilms, we revise the analytical methods to characterize them quantitatively and qualitatively and finally we provide an overview of potential new antimicrobial therapies able to inhibit biofilm formation by targeting exopolysaccharides. | 2023 | 36835442 |
| 8240 | 2 | 0.9993 | β-glucan-induced disease resistance in plants: A review. Systemic acquired resistance (SAR) and induced systemic resistance (ISR) are caused by various factors, including both pathogenic and non-pathogenic ones. β-glucan primarily originates from bacteria and fungi, some species of these organisms work as biological agents in causing diseases. When β-glucan enters plants, it triggers the defense system, leading to various reactions such as the production of proteins related to pathogenicity and defense enzymes. By extracting β-glucan from disturbed microorganisms and using it as an inducing agent, plant diseases can be effectively controlled by activating the plant's defense system. β-glucan plays a crucial role during the interaction between plants and pathogens. Therefore, modeling the plant-pathogen relationship and using the molecules involved in this interaction can help in controlling plant diseases, as pathogens have genes related to resistance against pathogenicity. Thus, it is reasonable to identify and use biological induction agents at a large scale by extracting these compounds. | 2023 | 37742892 |
| 9328 | 3 | 0.9993 | Man-made cell-like compartments for molecular evolution. Cellular compartmentalization is vital for the evolution of all living organisms. Cells keep together the genes, the RNAs and proteins that they encode, and the products of their activities, thus linking genotype to phenotype. We have reproduced this linkage in the test tube by transcribing and translating single genes in the aqueous compartments of water-in-oil emulsions. These compartments, with volumes close to those of bacteria, can be recruited to select genes encoding catalysts. A protein or RNA with a desired catalytic activity converts a substrate attached to the gene that encodes it to product. In other compartments, substrates attached to genes that do not encode catalysts remain unmodified. Subsequently, genes encoding catalysts are selectively enriched by virtue of their linkage to the product. We demonstrate the linkage of genotype to phenotype in man-made compartments using a model system. A selection for target-specific DNA methylation was based on the resistance of the product (methylated DNA) to restriction digestion. Genes encoding HaeIII methyltransferase were selected from a 10(7)-fold excess of genes encoding another enzyme. | 1998 | 9661199 |
| 8241 | 4 | 0.9992 | Molecular mechanisms of N-acyl homoserine lactone signals perception by plants. N-acyl homoserine lactones (AHLs) belong to the class of bacterial quorum sensing signal molecules involved in distance signal transduction between Gram-negative bacteria colonizers of the rhizosphere, as well as bacteria and plants. AHLs synchronize the activity of genes from individual cells, allowing the bacterial population to act as a multicellular organism, and establish a symbiotic or antagonistic relationship with the host plant. Although the effect of AHLs on plants has been studied for more than ten years, the mechanisms of plant perception of AHL signals are not fully understood. The specificity of the reactions caused by AHL indicates the existence of appropriate mechanisms for their perception by plants. In the current review, we summarize available data on the molecular mechanisms of AHL-signal perception in plants, its effect on plant growth, development, and stress resistance. We describe the latest research demonstrating direct (on plants) and indirect (on rhizosphere microflora) effects of AHLs, as well as the prospects of using these compounds in biotechnology to increase plant resistance to biotic and abiotic stresses. | 2022 | 34937124 |
| 9153 | 5 | 0.9992 | Mycoplasma Contamination of Cell Cultures: Vesicular Traffic in Bacteria and Control over Infectious Agents. Cell cultures are subject to contamination either with cells of other cultures or with microorganisms, including fungi, viruses, and bacteria. Mycoplasma contamination of cell cultures is of particular importance. Since cell cultures are used for the production of vaccines and physiologically active compounds, designing a system for controlling contaminants becomes topical for fundamental science and biotechnological production. The discovery of extracellular membrane vesicles in mycoplasmas makes it necessary to take into consideration the bacterial vesicular traffic in systems designed for controlling infectious agents. The extracellular vesicles of bacteria mediate the traffic of proteins and genes, participate in cell-to-cell interactions, as well as in the pathogenesis and development of resistance to antibiotics. The present review discusses the features of mycoplasmas, their extracellular vesicles, and the interaction between contaminants and eukaryotic cells. Furthermore, it provides an analysis of the problems associated with modern methods of diagnosis and eradication of mycoplasma contamination from cell cultures and prospects for their solution. | 2014 | 25349713 |
| 9426 | 6 | 0.9992 | Determination of Effects and Mechanisms of Action of Bacterial Amyloids on Antibiotic Resistance. Bacterial functional amyloids, apart from their many other functions, can influence the resistance of bacteria to antibiotics and other antibacterial agents. Mechanisms of modulation of susceptibility of bacterial cells to antimicrobials can be either indirect or direct. The former mechanisms are exemplified by the contribution of functional amyloids to biofilm formation, which may effectively prevent the penetration of various compounds into bacterial cells. The direct mechanisms include the effects of bacterial proteins revealing amyloid-like structures, like the C-terminal region of the Escherichia coli Hfq protein, on the expression of genes involved in antibiotic resistance. Therefore, in this paper, we describe methods by which effects and mechanisms of action of bacterial amyloids on antibiotic resistance can be studied. Assessment of formation of biofilms, determination of the efficiency of antibiotic resistance in solid and liquid media, and determination of the effects on gene expression at levels of mRNA abundance and stability and protein abundance are described. | 2022 | 35951301 |
| 9151 | 7 | 0.9992 | Bacterial exo-polysaccharides in biofilms: role in antimicrobial resistance and treatments. BACKGROUND: Bacterial biofilms are aggregation or collection of different bacterial cells which are covered by self-produced extracellular matrix and are attached to a substratum. Generally, under stress or in unfavorable conditions, free planktonic bacteria transform themselves into bacterial biofilms and become sessile. MAIN BODY: Various mechanisms involving interaction between antimicrobial and biofilm matrix components, reduced growth rates, and genes conferring antibiotic resistance have been described to contribute to enhanced resistance. Quorum sensing and multi-drug resistance efflux pumps are known to regulate the internal environment within the biofilm as well as biofilm formation; they also protect cells from antibiotic attack or immune attacks. This review summarizes data supporting the importance of exopolysaccharides during biofilm formation and its role in antibiotic resistance. CONCLUSIONS: Involvement of quorum sensing and efflux pumps in antibiotic resistance in association with exopolysaccharides. Also, strategies to overcome or attack biofilms are provided. | 2021 | 34557983 |
| 8324 | 8 | 0.9992 | Bile Sensing: The Activation of Vibrio parahaemolyticus Virulence. Bacteria must develop resistance to various inhospitable conditions in order to survive in the human gastrointestinal tract. Bile, which is secreted by the liver, and plays an important role in food digestion also has antimicrobial properties and is able to disrupt cellular homeostasis. Paradoxically, although bile is one of the guts defenses, many studies have reported that bacteria such as Vibrio parahaemolyticus can sense bile and use its presence as an environmental cue to upregulate virulence genes during infection. This article aims to discuss how bile is detected by V. parahaemolyticus and its role in regulating type III secretion system 2 leading to human infection. This bile-bacteria interaction pathway gives us a clearer understanding of the biochemical and structural analysis of the bacterial receptors involved in mediating a response to bile salts which appear to be a significant environmental cue during initiation of an infection. | 2017 | 28484445 |
| 9337 | 9 | 0.9992 | Predation-resistant Pseudomonas bacteria engage in symbiont-like behavior with the social amoeba Dictyostelium discoideum. The soil amoeba Dictyostelium discoideum acts as both a predator and potential host for diverse bacteria. We tested fifteen Pseudomonas strains that were isolated from transiently infected wild D. discoideum for ability to escape predation and infect D. discoideum fruiting bodies. Three predation-resistant strains frequently caused extracellular infections of fruiting bodies but were not found within spores. Furthermore, infection by one of these species induces secondary infections and suppresses predation of otherwise edible bacteria. Another strain can persist inside of amoebae after being phagocytosed but is rarely taken up. We sequenced isolate genomes and discovered that predation-resistant isolates are not monophyletic. Many Pseudomonas isolates encode secretion systems and toxins known to improve resistance to phagocytosis in other species, as well as diverse secondary metabolite biosynthetic gene clusters that may contribute to predation resistance. However, the distribution of these genes alone cannot explain why some strains are edible and others are not. Each lineage may employ a unique mechanism for resistance. | 2023 | 37884792 |
| 9356 | 10 | 0.9992 | The expression of antibiotic resistance genes in antibiotic-producing bacteria. Antibiotic-producing bacteria encode antibiotic resistance genes that protect them from the biologically active molecules that they produce. The expression of these genes needs to occur in a timely manner: either in advance of or concomitantly with biosynthesis. It appears that there have been at least two general solutions to this problem. In many cases, the expression of resistance genes is tightly linked to that of antibiotic biosynthetic genes. In others, the resistance genes can be induced by their cognate antibiotics or by intermediate molecules from their biosynthetic pathways. The regulatory mechanisms that couple resistance to antibiotic biosynthesis are mechanistically diverse and potentially relevant to the origins of clinical antibiotic resistance. | 2014 | 24964724 |
| 8388 | 11 | 0.9992 | Essential genes from Arctic bacteria used to construct stable, temperature-sensitive bacterial vaccines. All bacteria share a set of evolutionarily conserved essential genes that encode products that are required for viability. The great diversity of environments that bacteria inhabit, including environments at extreme temperatures, place adaptive pressure on essential genes. We sought to use this evolutionary diversity of essential genes to engineer bacterial pathogens to be stably temperature-sensitive, and thus useful as live vaccines. We isolated essential genes from bacteria found in the Arctic and substituted them for their counterparts into pathogens of mammals. We found that substitution of nine different essential genes from psychrophilic (cold-loving) bacteria into mammalian pathogenic bacteria resulted in strains that died below their normal-temperature growth limits. Substitution of three different psychrophilic gene orthologs of ligA, which encode NAD-dependent DNA ligase, resulted in bacterial strains that died at 33, 35, and 37 degrees C. One ligA gene was shown to render Francisella tularensis, Salmonella enterica, and Mycobacterium smegmatis temperature-sensitive, demonstrating that this gene functions in both Gram-negative and Gram-positive lineage bacteria. Three temperature-sensitive F. tularensis strains were shown to induce protective immunity after vaccination at a cool body site. About half of the genes that could be tested were unable to mutate to temperature-resistant forms at detectable levels. These results show that psychrophilic essential genes can be used to create a unique class of bacterial temperature-sensitive vaccines for important human pathogens, such as S. enterica and Mycobacterium tuberculosis. | 2010 | 20624965 |
| 9425 | 12 | 0.9992 | A review of the current evidence of fruit phenolic compounds as potential antimicrobials against pathogenic bacteria. Fruits are among the main natural sources of phenolic compounds (PC). These compounds exert important antioxidant properties primarily associated with the presence of hydroxyl groups in their molecular structure. Additionally, the antibacterial effects of fruit phenolic-rich extracts or individual PC commonly found in fruits have been an emerging research focus in recent years. This review discusses by first time the available literature regarding the inhibitory effects of fruit PC on pathogenic bacteria, including not only their direct effects on bacterial growth and survival, but also their effects on virulence factors and antibiotic resistance, as well as the possible mechanism underlying these inhibitory properties. The results of the retrieved studies show overall that the antibacterial effects of fruit PC vary with the target bacteria, type of PC and length of exposure to these compounds. The type of solvent and procedures used for extraction and fruit cultivar also seem to influence the antibacterial effects of phenolic-rich fruit extracts. Fruit PC have shown wide-spectrum antibacterial properties besides being effective antibiotic resistance modifying agents in pathogenic bacteria and these effects have shown to be associated with interruption of efflux pump expression/function. Furthermore, fruit PC can cause down regulation of a variety of genes associated with virulence features in pathogenic bacteria. Results of available studies indicate the depolarization and alteration of membrane fluidity as mechanisms underlying the inhibition of pathogenic bacteria by fruit PC. These data reveal fruit PC have potential antimicrobial properties, which should be rationally exploited in solutions to control pathogenic bacteria. | 2019 | 30917922 |
| 9429 | 13 | 0.9992 | Basic features of biofilms--why are they difficult therapeutic targets? The purpose of this paper is to review the basic features of biofilms associated with human infections and summarize why such biofilms are resistant to antimicrobial agents. The formation of most biofilms involves adherence of bacteria to a conditioned surface, growth and division of the attached bacteria, synthesis of a polymeric slime matrix, formation of a structured microbial community, and incorporation of other micro-organisms into the microbial mass. The transition of bacteria from free-floating (planktonic) to biofilm environments involves extensive up-regulation of genes associated with adherence. Micro-organisms in established biofilms engage in complex integrated activities involving activation and deactivation of genes that promote the survival of bacteria within the biofilm community. Mechanisms of the increased resistance of biofilm bacteria to antimicrobial agents may involve: (1) neutralization or consumption of the drug, (2) failure of the drug to completely penetrate the biofilm, (3) inability of the drug to affect metabolically inactive bacteria, and (4) presence of drug-resistant bacteria within biofilms. | 2004 | 16479852 |
| 9336 | 14 | 0.9992 | Molecular dissection of nutrient exchange at the insect-microbial interface. Genome research is transforming our understanding of nutrient exchange between insects and intracellular bacteria. A key characteristic of these bacteria is their small genome size and gene content. Their fastidious and inflexible nutritional requirements are met by multiple metabolites from the insect host cell. Although the bacteria have generally retained genes coding the synthesis of nutrients required by the insect, some apparently critical genes have been lost, and compensated for by shared metabolic pathways with the insect host or supplementary bacteria with complementary metabolic capabilities. | 2014 | 28043404 |
| 9338 | 15 | 0.9992 | Polyamines in bacteria: pleiotropic effects yet specific mechanisms. Extensive data in a wide range of organisms point to the importance of polyamine homeostasis for growth. The two most common polyamines found in bacteria are putrescine and spermidine. The investigation of polyamine function in bacteria has revealed that they are involved in a number of functions other than growth, which include incorporation into the cell wall and biosynthesis of siderophores. They are also important in acid resistance and can act as a free radical ion scavenger. More recently it has been suggested that polyamines play a potential role in signaling cellular differentiation in Proteus mirabilis. Polyamines have also been shown to be essential in biofilm formation in Yersinia pestis. The pleiotropic nature of polyamines has made their investigation difficult, particularly in discerning any specific effect from more global growth effects. Here we describe key developments in the investigation of the function of polyamines in bacteria that have revealed new roles for polyamines distinct from growth. We describe the bacterial genes necessary for biosynthesis and transport, with a focus on Y. pestis. Finally we review a novel role for polyamines in the regulation of biofilm development in Y. pestis and provide evidence that the investigation of polyamines in Y. pestis may provide a model for understanding the mechanism through which polyamines regulate biofilm formation. | 2007 | 17966408 |
| 8317 | 16 | 0.9992 | The Quorum Sensing Auto-Inducer 2 (AI-2) Stimulates Nitrogen Fixation and Favors Ethanol Production over Biomass Accumulation in Zymomonas mobilis. Autoinducer 2 (or AI-2) is one of the molecules used by bacteria to trigger the Quorum Sensing (QS) response, which activates expression of genes involved in a series of alternative mechanisms, when cells reach high population densities (including bioluminescence, motility, biofilm formation, stress resistance, and production of public goods, or pathogenicity factors, among others). Contrary to most autoinducers, AI-2 can induce QS responses in both Gram-negative and Gram-positive bacteria, and has been suggested to constitute a trans-specific system of bacterial communication, capable of affecting even bacteria that cannot produce this autoinducer. In this work, we demonstrate that the ethanologenic Gram-negative bacterium Zymomonas mobilis (a non-AI-2 producer) responds to exogenous AI-2 by modulating expression of genes involved in mechanisms typically associated with QS in other bacteria, such as motility, DNA repair, and nitrogen fixation. Interestingly, the metabolism of AI-2-induced Z. mobilis cells seems to favor ethanol production over biomass accumulation, probably as an adaptation to the high-energy demand of N(2) fixation. This opens the possibility of employing AI-2 during the industrial production of second-generation ethanol, as a way to boost N(2) fixation by these bacteria, which could reduce costs associated with the use of nitrogen-based fertilizers, without compromising ethanol production in industrial plants. | 2021 | 34073173 |
| 9096 | 17 | 0.9992 | Enhanced antibacterial activity of surface re-engineered lysozyme against Gram-negative bacteria without accumulated resistance. In this study, we show a way to improve the antibacterial activity of lysozyme by incorporating guanidino functional groups onto its surface (Lyz-Gua), which could treat pathogenic bacteria without accumulated resistance and shows advantages over commercial antibiotics. | 2022 | 35876097 |
| 8223 | 18 | 0.9992 | Biogenic ammonia modifies antibiotic resistance at a distance in physically separated bacteria. Bacteria release low-molecular-weight by-products called secondary metabolites, which contribute to bacterial ecology and biology. Whereas volatile compounds constitute a large class of potential infochemicals, their role in bacteria-bacteria interactions remains vastly unexplored. Here we report that exposure to gaseous ammonia released from stationary-phase bacterial cultures modifies the antibiotic resistance spectrum of all tested Gram-negative and Gram-positive bacteria. Using Escherichia coli K12 as a model organism, and increased resistance to tetracycline as the phenotypic read-out, we demonstrate that exposure to ammonia generated by the catabolism of l-aspartate increases the level of intracellular polyamines, in turn leading to modifications in membrane permeability to different antibiotics as well as increased resistance to oxidative stress. We show that the inability to import ammonia via the Amt gas channel or to synthesize polyamines prevent modification in the resistance profile of aerially exposed bacteria. We therefore provide here the first detailed molecular characterization of widespread, long-range chemical interference between physically separated bacteria. | 2011 | 21651627 |
| 8242 | 19 | 0.9992 | New antibacterial targets: Regulation of quorum sensing and secretory systems in zoonotic bacteria. Quorum sensing (QS) is a communication mechanism that controls bacterial communication and can influence the transcriptional expression of multiple genes through one or more signaling molecules, thereby coordinating the population response of multiple bacterial pathogens. Secretion systems (SS) play an equally important role in bacterial information exchange, relying on the secretory systems to secrete proteins that act as virulence factors to promote adhesion to host cells. Eight highly efficient SS have been described, all of which are involved in the secretion or transfer of virulence factors, and the effector proteins they secrete play a key role in the virulence and pathogenicity of bacteria. It has been shown that many bacterial SS are directly or indirectly regulated by QS and thus influence bacterial virulence and antibiotic resistance. This review describes the relationship between QS and SS of several common zoonotic pathogenic bacteria and outlines the molecular mechanisms of how QS systems regulate SS, to provide a theoretical basis for the study of bacterial pathogenicity and the development of novel antibacterial drugs. | 2023 | 37343493 |