# | Rank | Similarity | Title + Abs. | Year | PMID |
|---|---|---|---|---|---|
| 0 | 1 | 2 | 3 | 4 | 5 |
| 8470 | 0 | 0.9963 | Genomic Insights into Vaccinium spp. Endophytes B. halotolerans and B. velezensis and Their Antimicrobial Potential. Plant microbiota contributes to nutrient absorption, and the production of hormones and vitamins, and plays a crucial role in responding to environmental stress. We hypothesized that Vaccinium spp. harbour a unique microbiota that enables them to coexist in extreme environments such as saline, nutrient-poor, and waterlogged conditions. Upon examining Bacillus spp. endophytes isolated from blueberries, cranberries and lingonberries in vitro, we identified B. halotolerans (Bil-LT1_1, Bil-LT1_2) and B. velezensis (Cran-LT1_8, Ling-NOR4_15) strains that inhibit the growth of five pathogenic fungi and five foodborne bacteria. Whole-genome sequencing provided insights into genome organization and plasticity, helping identify mobile elements and genes potentially acquired through horizontal gene transfer. Functional annotation identified genes associated with plant colonization, stress tolerance, biocontrol activity, and plant growth promotion. Comparative genomic analyses revealed key biosynthetic gene clusters (BGCs) responsible for producing antifungal metabolites, including lipopeptides and polyketides. Genes supporting plant nutrition, growth, and environmental adaptation were present also in these strains. Notably, isolated endophytes exhibited particularly high levels of genomic plasticity, likely due to horizontal gene transfer involving gene ontology (GO) pathways related to survival in polymicrobial and foreign environments. | 2025 | 40724928 |
| 8360 | 1 | 0.9960 | Genome mining of Streptomyces scabrisporus NF3 reveals symbiotic features including genes related to plant interactions. Endophytic bacteria are wide-spread and associated with plant physiological benefits, yet their genomes and secondary metabolites remain largely unidentified. In this study, we explored the genome of the endophyte Streptomyces scabrisporus NF3 for discovery of potential novel molecules as well as genes and metabolites involved in host interactions. The complete genomes of seven Streptomyces and three other more distantly related bacteria were used to define the functional landscape of this unique microbe. The S. scabrisporus NF3 genome is larger than the average Streptomyces genome and not structured for an obligate endosymbiotic lifestyle; this and the fact that can grow in R2YE media implies that it could include a soil-living stage. The genome displays an enrichment of genes associated with amino acid production, protein secretion, secondary metabolite and antioxidants production and xenobiotic degradation, indicating that S. scabrisporus NF3 could contribute to the metabolic enrichment of soil microbial communities and of its hosts. Importantly, besides its metabolic advantages, the genome showed evidence for differential functional specificity and diversification of plant interaction molecules, including genes for the production of plant hormones, stress resistance molecules, chitinases, antibiotics and siderophores. Given the diversity of S. scabrisporus mechanisms for host upkeep, we propose that these strategies were necessary for its adaptation to plant hosts and to face changes in environmental conditions. | 2018 | 29447216 |
| 664 | 2 | 0.9959 | Ferric Uptake Regulator Provides a New Strategy for Acidophile Adaptation to Acidic Ecosystems. Acidophiles play a dominant role in driving elemental cycling in natural acid mine drainage (AMD) habitats and exhibit important application value in bioleaching and bioremediation. Acidity is an inevitable environmental stress and a key factor that affects the survival of acidophiles in their acidified natural habitats; however, the regulatory strategies applied by acidophilic bacteria to withstand low pH are unclear. We identified the significance of the ferric uptake regulator (Fur) in acidophiles adapting to acidic environments and discovered that Fur is ubiquitous as well as highly conserved in acidophilic bacteria. Mutagenesis of the fur gene of Acidithiobacillus caldus, a prototypical acidophilic sulfur-oxidizing bacterium found in AMD, revealed that Fur is required for the acid resistance of this acidophilic bacterium. Phenotypic characterization, transcriptome sequencing (RNA-seq), mutagenesis, and biochemical assays indicated that the Acidithiobacillus caldus ferric uptake regulator (AcFur) is involved in extreme acid resistance by regulating the expression of several key genes of certain cellular activities, such as iron transport, biofilm formation, sulfur metabolism, chemotaxis, and flagellar biosynthesis. Finally, a Fur-dependent acid resistance regulatory strategy in A. caldus was proposed to illustrate the ecological behavior of acidophilic bacteria under low pH. This study provides new insights into the adaptation strategies of acidophiles to AMD ecosystems and will promote the design and development of engineered biological systems for the environmental adaptation of acidophiles.IMPORTANCE This study advances our understanding of the acid tolerance mechanism of A. caldus, identifies the key fur gene responsible for acid resistance, and elucidates the correlation between fur and acid resistance, thus contributing to an understanding of the ecological behavior of acidophilic bacteria. These findings provide new insights into the acid resistance process in Acidithiobacillus species, thereby promoting the study of the environmental adaptation of acidophilic bacteria and the design of engineered biological systems. | 2020 | 32245756 |
| 8672 | 3 | 0.9959 | Pangenomic and functional investigations for dormancy and biodegradation features of an organic pollutant-degrading bacterium Rhodococcus biphenylivorans TG9. Environmental bacteria contain a wealth of untapped potential in the form of biodegradative genes. Leveraging this potential can often be confounded by a lack of understanding of fundamental survival strategies, like dormancy, for environmental stress. Investigating bacterial dormancy-to-degradation relationships enables improvement of bioremediation. Here, we couple genomic and functional assessment to provide context for key attributes of the organic pollutant-degrading strain Rhodococcus biphenylivorans TG9. Whole genome sequencing, pangenome analysis and functional characterization were performed to elucidate important genes and gene products, including antimicrobial resistance, dormancy, and degradation. Rhodococcus as a genus has strong potential for degradation and dormancy, which we demonstrate using R. biphenylivorans TG9 as a model. We identified four Resuscitation-promoting factor (Rpf) encoding genes in TG9 involved in dormancy and resuscitation. We demonstrate that R. biphenylivorans TG9 grows on fourteen typical organic pollutants, and exhibits a robust ability to degrade biphenyl and several congeners of polychlorinated biphenyls. We further induced TG9 into a dormant state and demonstrated pronounced differences in morphology and activity. Together, these results expand our understanding of the genus Rhodococcus and the relationship between dormancy and biodegradation in the presence of environmental stressors. | 2022 | 34688761 |
| 8636 | 4 | 0.9959 | Insights into the synthesis, engineering, and functions of microbial pigments in Deinococcus bacteria. The ability of Deinococcus bacteria to survive in harsh environments, such as high radiation, extreme temperature, and dryness, is mainly attributed to the generation of unique pigments, especially carotenoids. Although the limited number of natural pigments produced by these bacteria restricts their industrial potential, metabolic engineering and synthetic biology can significantly increase pigment yield and expand their application prospects. In this study, we review the properties, biosynthetic pathways, and functions of key enzymes and genes related to these pigments and explore strategies for improving pigment production through gene editing and optimization of culture conditions. Additionally, studies have highlighted the unique role of these pigments in antioxidant activity and radiation resistance, particularly emphasizing the critical functions of deinoxanthin in D. radiodurans. In the future, Deinococcus bacterial pigments will have broad application prospects in the food industry, drug production, and space exploration, where they can serve as radiation indicators and natural antioxidants to protect astronauts' health during long-term space flights. | 2024 | 39119139 |
| 8714 | 5 | 0.9958 | Tales from the tomb: the microbial ecology of exposed rock surfaces. Although a broad diversity of eukaryotic and bacterial taxa reside on rock surfaces where they can influence the weathering of rocks and minerals, these communities and their contributions to mineral weathering remain poorly resolved. To build a more comprehensive understanding of the diversity, ecology and potential functional attributes of microbial communities living on rock, we sampled 149 tombstones across three continents and analysed their bacterial and eukaryotic communities via marker gene and shotgun metagenomic sequencing. We found that geographic location and climate were important factors structuring the composition of these communities. Moreover, the tombstone-associated microbial communities varied as a function of rock type, with granite and limestone tombstones from the same cemeteries harbouring taxonomically distinct microbial communities. The granite and limestone-associated communities also had distinct functional attributes, with granite-associated bacteria having more genes linked to acid tolerance and chemotaxis, while bacteria on limestone were more likely to be lichen associated and have genes involved in photosynthesis and radiation resistance. Together these results indicate that rock-dwelling microbes exhibit adaptations to survive the stresses of the rock surface, differ based on location, climate and rock type, and seem pre-disposed to different ecological strategies (symbiotic versus free-living lifestyles) depending on the rock type. | 2018 | 29235707 |
| 8647 | 6 | 0.9958 | Eco-evolutionary strategies for relieving carbon limitation under salt stress differ across microbial clades. With the continuous expansion of saline soils under climate change, understanding the eco-evolutionary tradeoff between the microbial mitigation of carbon limitation and the maintenance of functional traits in saline soils represents a significant knowledge gap in predicting future soil health and ecological function. Through shotgun metagenomic sequencing of coastal soils along a salinity gradient, we show contrasting eco-evolutionary directions of soil bacteria and archaea that manifest in changes to genome size and the functional potential of the soil microbiome. In salt environments with high carbon requirements, bacteria exhibit reduced genome sizes associated with a depletion of metabolic genes, while archaea display larger genomes and enrichment of salt-resistance, metabolic, and carbon-acquisition genes. This suggests that bacteria conserve energy through genome streamlining when facing salt stress, while archaea invest in carbon-acquisition pathways to broaden their resource usage. These findings suggest divergent directions in eco-evolutionary adaptations to soil saline stress amongst microbial clades and serve as a foundation for understanding the response of soil microbiomes to escalating climate change. | 2024 | 39019914 |
| 8671 | 7 | 0.9958 | Adapting to UV: Integrative Genomic and Structural Analysis in Bacteria from Chilean Extreme Environments. Extremophilic bacteria from extreme environments, such as the Atacama Desert, Salar de Huasco, and Antarctica, exhibit adaptations to intense UV radiation. In this study, we investigated the genomic and structural mechanisms underlying UV resistance in three bacterial isolates identified as Bacillus velezensis PQ169, Pseudoalteromonas sp. AMH3-8, and Rugamonas violacea T1-13. Through integrative genomic analyses, we identified key genes involved in DNA-repair systems, pigment production, and spore formation. Phylogenetic analyses of aminoacidic sequences of the nucleotide excision repair (NER) system revealed conserved evolutionary patterns, indicating their essential role across diverse bacterial taxa. Structural modeling of photolyases from Pseudoalteromonas sp. AMH3-8 and R. violacea T1-13 provided further insights into protein function and interactions critical for DNA repair and UV resistance. Additionally, the presence of a complete violacein operon in R. violacea T1-13 underscores pigment biosynthesis as a crucial protective mechanism. In B. velezensis PQ169, we identified the complete set of genes responsible for sporulation, suggesting that sporulation may represent a key protective strategy employed by this bacterium in response to environmental stress. Our comprehensive approach underscores the complexity and diversity of microbial adaptations to UV stress, offering potential biotechnological applications and advancing our understanding of microbial resilience in extreme conditions. | 2025 | 40565314 |
| 9345 | 8 | 0.9958 | Replacement of the arginine biosynthesis operon in Xanthomonadales by lateral gene transfer. The role of lateral gene transfer (LGT) in prokaryotes has been shown to rapidly change the genome content, providing new gene tools for environmental adaptation. Features related to pathogenesis and resistance to strong selective conditions have been widely shown to be products of gene transfer between bacteria. The genomes of the gamma-proteobacteria from the genus Xanthomonas, composed mainly of phytopathogens, have potential genomic islands that may represent imprints of such evolutionary processes. In this work, the evolution of genes involved in the pathway responsible for arginine biosynthesis in Xanthomonadales was investigated, and several lines of evidence point to the foreign origin of the arg genes clustered within a potential operon. Their presence inside a potential genomic island, bordered by a tRNA gene, the unusual ranking of sequence similarity, and the atypical phylogenies indicate that the metabolic pathway for arginine biosynthesis was acquired through LGT in the Xanthomonadales group. Moreover, although homologues were also found in Bacteroidetes (Flavobacteria group), for many of the genes analyzed close homologues are detected in different life domains (Eukarya and Archaea), indicating that the source of these arg genes may have been outside the Bacteria clade. The possibility of replacement of a complete primary metabolic pathway by LGT events supports the selfish operon hypothesis and may occur only under very special environmental conditions. Such rare events reveal part of the history of these interesting mosaic Xanthomonadales genomes, disclosing the importance of gene transfer modifying primary metabolism pathways and extending the scenario for bacterial genome evolution. | 2008 | 18305979 |
| 141 | 9 | 0.9957 | Plant growth-promoting activities and genomic analysis of the stress-resistant Bacillus megaterium STB1, a bacterium of agricultural and biotechnological interest. In this work, the stress-resistant Bacillus megaterium STB1 is characterized and its ability to promote plant growth under normal and stress conditions is demonstrated. The genomic sequence of this bacterium, and a detailed analysis of the genes involved in facilitating its stress resistance and plant growth-promoting activities is also reported. The B. megaterium STB1 genome is rich in genetic elements involved in multiple stress resistance, xenobiotic degradation, pathogen antagonistic activities, and other traits related to soil and rhizosphere colonization. Moreover, genes participating in the biosynthesis of auxins and cytokinins, the modulation of polyamines, GABA, brassinosteroids and ethylene levels were also found. Ultimately, this study brings new insights into the role of B. megaterium as a plant growth-promoting bacterium and opens new opportunities for the development of novel strategies for agriculture and biotechnology. | 2020 | 31886139 |
| 8362 | 10 | 0.9957 | Lifestyle evolution in symbiotic bacteria: insights from genomics. Bacteria that live only in eukaryotic cells and tissues, including chronic pathogens and mutualistic bacteriocyte associates, often possess a distinctive set of genomic traits, including reduced genome size, biased nucleotide base composition and fast polypeptide evolution. These phylogenetically diverse bacteria have lost certain functional categories of genes, including DNA repair genes, which affect mutational patterns. However, pathogens and mutualistic symbionts retain loci that underlie their unique interaction types, such as genes enabling nutrient provisioning by mutualistic bacteria-inhabiting animals. Recent genomic studies suggest that many of these bacteria are irreversibly specialized, precluding shifts between pathogenesis and mutualism. | 2000 | 10884696 |
| 7674 | 11 | 0.9957 | Insights into gut microbiomes in stem cell transplantation by comprehensive shotgun long-read sequencing. The gut microbiome is a diverse ecosystem, dominated by bacteria; however, fungi, phages/viruses, archaea, and protozoa are also important members of the gut microbiota. Exploration of taxonomic compositions beyond bacteria as well as an understanding of the interaction between the bacteriome with the other members is limited using 16S rDNA sequencing. Here, we developed a pipeline enabling the simultaneous interrogation of the gut microbiome (bacteriome, mycobiome, archaeome, eukaryome, DNA virome) and of antibiotic resistance genes based on optimized long-read shotgun metagenomics protocols and custom bioinformatics. Using our pipeline we investigated the longitudinal composition of the gut microbiome in an exploratory clinical study in patients undergoing allogeneic hematopoietic stem cell transplantation (alloHSCT; n = 31). Pre-transplantation microbiomes exhibited a 3-cluster structure, characterized by Bacteroides spp. /Phocaeicola spp., mixed composition and Enterococcus abundances. We revealed substantial inter-individual and temporal variabilities of microbial domain compositions, human DNA, and antibiotic resistance genes during the course of alloHSCT. Interestingly, viruses and fungi accounted for substantial proportions of microbiome content in individual samples. In the course of HSCT, bacterial strains were stable or newly acquired. Our results demonstrate the disruptive potential of alloHSCTon the gut microbiome and pave the way for future comprehensive microbiome studies based on long-read metagenomics. | 2024 | 38374282 |
| 8249 | 12 | 0.9957 | Biocontrol Traits Correlate With Resistance to Predation by Protists in Soil Pseudomonads. Root-colonizing bacteria can support plant growth and help fend off pathogens. It is clear that such bacteria benefit from plant-derived carbon, but it remains ambiguous why they invest in plant-beneficial traits. We suggest that selection via protist predation contributes to recruitment of plant-beneficial traits in rhizosphere bacteria. To this end, we examined the extent to which bacterial traits associated with pathogen inhibition coincide with resistance to protist predation. We investigated the resistance to predation of a collection of Pseudomonas spp. against a range of representative soil protists covering three eukaryotic supergroups. We then examined whether patterns of resistance to predation could be explained by functional traits related to plant growth promotion, disease suppression and root colonization success. We observed a strong correlation between resistance to predation and phytopathogen inhibition. In addition, our analysis highlighted an important contribution of lytic enzymes and motility traits to resist predation by protists. We conclude that the widespread occurrence of plant-protective traits in the rhizosphere microbiome may be driven by the evolutionary pressure for resistance against predation by protists. Protists may therefore act as microbiome regulators promoting native bacteria involved in plant protection against diseases. | 2020 | 33384680 |
| 8336 | 13 | 0.9957 | Global copper response of the soil bacterial predator Myxococcus xanthus and its contribution to antibiotic cross-resistance. Copper accumulation in agricultural soils poses environmental challenges by selecting copper-resistant bacteria and also contributing to the co-selection of antibiotic-resistant bacteria. In addition, copper influences bacterial predator-prey interactions, potentially altering microbial ecosystems. Myxococcus xanthus, a soil-dwelling bacterium, preys on other microorganisms, including Sinorhizobium meliloti, a symbiotic nitrogen-fixing bacterium associated with leguminous plants. The role of copper in M. xanthus interactions remains poorly understood, although it accumulates at the predator-prey interface. In this study, we explore the transcriptomic response of M. xanthus to copper stress in both monocultures and co-cultures with S. meliloti. Our analysis identified many myxobacterial copper-regulated transcripts, and studies on mutant strains in some copper-induced genes revealed the role of two efflux pumps in cross-resistance to copper and tetracyclines. These findings provide new insights into the adaptive mechanisms of M. xanthus in response to copper, with implications for the co-selection of antibiotic resistance and the broader impact of copper on microbial community dynamics in soil ecosystems. | 2026 | 41061564 |
| 8706 | 14 | 0.9957 | Analysis of 16S rRNA and mxaF genes revealing insights into Methylobacterium niche-specific plant association. The genus Methylobacterium comprises pink-pigmented facultative methylotrophic (PPFM) bacteria, known to be an important plant-associated bacterial group. Species of this group, described as plant-nodulating, have the dual capacity of producing cytokinin and enzymes, such as pectinase and cellulase, involved in systemic resistance induction and nitrogen fixation under specific plant environmental conditions. The aim hereby was to evaluate the phylogenetic distribution of Methylobacterium spp. isolates from different host plants. Thus, a comparative analysis between sequences from structural (16S rRNA) and functional mxaF (which codifies for a subunit of the enzyme methanol dehydrogenase) ubiquitous genes, was undertaken. Notably, some Methylobacterium spp. isolates are generalists through colonizing more than one host plant, whereas others are exclusively found in certain specific plant-species. Congruency between phylogeny and specific host inhabitance was higher in the mxaF gene than in the 16S rRNA, a possible indication of function-based selection in this niche. Therefore, in a first stage, plant colonization by Methylobacterium spp. could represent generalist behavior, possibly related to microbial competition and adaptation to a plant environment. Otherwise, niche-specific colonization is apparently impelled by the host plant. | 2012 | 22481887 |
| 8645 | 15 | 0.9957 | Resilience mechanisms of rhizosphere microorganisms in lead-zinc tailings: Metagenomic insights into heavy metal resistance. This study investigates the impact of heavy metal contamination in lead-zinc tailings on plant and soil microbial communities, focusing on the resilience mechanisms of rhizosphere microorganisms in these extreme environments. Utilizing metagenomic techniques, we identified a significant association between Coriaria nepalensis Wall. rhizosphere microbial communities and metal(loid) resistance genes. Our results reveal a notable diversity and abundance of bacteria within the rhizosphere of tailings, primarily consisting of Proteobacteria, Actinobacteria, and Chloroflexi. The presence of metal-resistant bacterial taxa, including Afipia, Bradyrhizobium, Sphingomonas, and Miltoncostaea, indicates specific evolutionary adaptations to metal-rich, nutrient-deficient environments. Elevated expression of resistance genes such as znuD, zntA, pbrB, and pbrT underscores the microorganisms' ability to endure these harsh conditions. These resistance genes are crucial for maintaining biodiversity, ecosystem stability, and adaptability. Our findings enhance the understanding of interactions between heavy metal contamination, microbial community structure, and resistance gene dynamics in lead-zinc tailings. Additionally, this research provides a theoretical and practical foundation for employing plant-microbial synergies in the in-situ remediation of contaminated sites. | 2025 | 40056745 |
| 9361 | 16 | 0.9956 | Evolutionary consequences of bacterial resistance to a flagellotropic phage. Bacteria often rapidly evolve resistance to bacteriophages (phages) by mutating or suppressing the phage-receptors, the factors that phages first target to initiate infection. Flagellotropic phages infect bacteria by initially binding to the flagellum. Since motility is an important fitness factor that allows bacteria to efficiently explore their environment, losing flagellar function to evade infection by flagellotropic phages represents a crucial trade-off. In this study, we investigated the evolutionary responses of Escherichia coli when exposed to the flagellotropic phage χ. Using an experimental evolution approach, E. coli cells were repeatedly subjected to environments rich in phage χ but selective for motility. Unlike traditional well-mixed cultures, we employed swim-plate assays to simulate spatial confinement and promote motility. Whole genome sequencing of evolved populations revealed early emergence of non-motile, χ-resistant mutants with mutations disrupting motility-related genes. Motile mutants emerged in later passages, possessing mutations in the flagellin gene fliC. Swim-plate assays showed a diverse range of motility among these mutants, with some displaying slower, and others faster, expansion speeds compared to the ancestral strain. Single-cell tracking experiments indicated an increased tumble bias in χ-resistant mutants, suggesting an adaptive response involving altered flagellar rotation. Our findings demonstrate that motility can undergo trade-offs and trade-ups with phage resistance, shedding light on the complex evolutionary dynamics between motile bacteria and flagellotropic phages. | 2025 | 40654869 |
| 8300 | 17 | 0.9956 | The Copper Resistome of Group B Streptococcus Reveals Insight into the Genetic Basis of Cellular Survival during Metal Ion Stress. In bacteria, copper (Cu) can support metabolic processes as an enzymatic cofactor but can also cause cell damage if present in excess, leading to intoxication. In group B Streptococcus (GBS), a system for control of Cu efflux based on the prototypical cop operon supports survival during Cu stress. In some other bacteria, genetic systems additional to the cop operon are engaged during Cu stress and also contribute to the management of cellular Cu homeostasis. Here, we examined genetic systems beyond the cop operon in GBS for regions that contribute to survival of GBS in Cu stress using a forward genetic screen and probe of the entire bacterial genome. A high-density mutant library, generated using pGh9-ISS1, was used to expose GBS to Cu stress and compare it to nonexposed controls en masse. Eight genes were identified as essential for GBS survival in Cu stress, whereas five genes constrained GBS growth in Cu stress. The genes encode varied factors including enzymes for metabolism, cell wall synthesis, transporters, and cell signaling factors. Targeted mutation of the genes validated their roles in GBS resistance to Cu stress. Excepting copA, the genes identified are new to the area of bacterial metal ion intoxication. We conclude that a discrete and limited suite of genes beyond the cop operon in GBS contributes to a repertoire of mechanisms used to survive Cu stress in vitro and achieve cellular homeostasis. IMPORTANCE Genetic systems for copper (Cu) homeostasis in bacteria, including streptococci, are vital to survive metal ion stress. Genetic systems that underpin survival of GBS during Cu stress, beyond the archetypal cop operon for Cu management, are undefined. We show that Streptococcus resists Cu intoxication by utilizing a discrete and limited suite of genes beyond the cop operon, including several genes that are new to the area of bacterial cell metal ion homeostasis. The Cu resistome of GBS defined here enhances our understanding of metal ion homeostasis in GBS. | 2022 | 35404113 |
| 8633 | 18 | 0.9956 | Bacterial interactions with arsenic: Metabolic pathways, resistance mechanisms, and bioremediation approaches. Arsenic contamination in natural waters is one of the biggest threats to human health, mainly due to its carcinogenic potential. Given its toxicity, nearly all organisms have evolved to develop an arsenic resistance mechanism. Conventional techniques of arsenic remediation suffer from various limitations of their applicability, cost and/or chemical intensive nature. In past few decades, bioremediation has emerged as a potential alternative to the conventional techniques. Microbial bioremediation, bacteria in particular, offers an eco-friendly and sustainable alternative, owing to its inherent metabolic capabilities to transform, immobilize or volatilize arsenic. Diverse biochemical pathways involving oxidation of As(III) to As(V), reduction of As(V) under anaerobic respiration or detoxification, methylation and demethylation, bioleaching and biomineralization into insoluble forms are essential mechanisms for arsenic remediation. These transformations, detoxification and resistance are regulated by specific genetic systems, including the ars operon, aio, arr and arsM, accessory genes such as arsR, arsB, acr3, arsC and arsP. The metabolic regulation of arsenic detoxification involves complex cofactor-dependent enzyme systems and environmental signal-responsive transcriptional control. Integrated approaches such as immobilization of bacteria on biochar or their encapsulation have also been known to enhance stability, reusability and stress tolerance. However, bioremediation is a very complex process due to the interrelationship of various influences such as, presence of specific microorganisms, nutrients and environmental factors. Therefore, it is of utmost importance to understand the bacterial interactions with arsenic for the development of bioremediation technologies. This review article tries to discuss the current status of arsenic bioremediation using bacteria, its field applications, challenges and future perspectives. It also includes the strengths, weaknesses, opportunities, threats (SWOT) analysis to assess the merits and demerits of using bacteria for bioremediation of arsenic. | 2025 | 41043264 |
| 8291 | 19 | 0.9956 | Pseudomonas Can Survive Tailocin Killing via Persistence-Like and Heterogenous Resistance Mechanisms. Phage tail-like bacteriocins (tailocins) are bacterially produced protein toxins that mediate competitive interactions between cocolonizing bacteria. Both theoretical and experimental research has shown there are intransitive interactions between bacteriocin-producing, bacteriocin-sensitive, and bacteriocin-resistant populations, whereby producers outcompete sensitive cells, sensitive cells outcompete resistant cells, and resistant cells outcompete producers. These so-called rock-paper-scissors dynamics explain how all three populations occupy the same environment, without one driving the others extinct. Using Pseudomonas syringae as a model, we demonstrate that otherwise sensitive cells survive bacteriocin exposure through a physiological mechanism. This mechanism allows cells to survive bacteriocin killing without acquiring resistance. We show that a significant fraction of the target cells that survive a lethal dose of tailocin did not exhibit any detectable increase in survival during a subsequent exposure. Tailocin persister cells were more prevalent in stationary- rather than log-phase cultures. Of the fraction of cells that gained detectable resistance, there was a range from complete (insensitive) to incomplete (partially sensitive) resistance. By using genomic sequencing and genetic engineering, we showed that a mutation in a hypothetical gene containing 8 to 10 transmembrane domains causes tailocin high persistence and that genes of various glycosyltransferases cause incomplete and complete tailocin resistance. Importantly, of the several classes of mutations, only those causing complete tailocin resistance compromised host fitness. This result indicates that bacteria likely utilize persistence to survive bacteriocin-mediated killing without suffering the costs associated with resistance. This research provides important insight into how bacteria can escape the trap of fitness trade-offs associated with gaining de novo tailocin resistance.IMPORTANCE Bacteriocins are bacterially produced protein toxins that are proposed as antibiotic alternatives. However, a deeper understanding of the responses of target bacteria to bacteriocin exposure is lacking. Here, we show that target cells of Pseudomonas syringae survive lethal bacteriocin exposure through both physiological persistence and genetic resistance mechanisms. Cells that are not growing rapidly rely primarily on persistence, whereas those growing rapidly are more likely to survive via resistance. We identified various mutations in lipopolysaccharide biogenesis-related regions involved in tailocin persistence and resistance. By assessing host fitness of various classes of mutants, we showed that persistence and subtle resistance are mechanisms P. syringae uses to survive competition and preserve host fitness. These results have important implications for developing bacteriocins as alternative therapeutic agents. | 2020 | 32312747 |