# | Rank | Similarity | Title + Abs. | Year | PMID |
|---|---|---|---|---|---|
| 0 | 1 | 2 | 3 | 4 | 5 |
| 8807 | 0 | 1.0000 | Dietary watermelon residue influencing the nonspecific immunity of juvenile Pseudorasbora parva. The study explored the improvement of disease resistance, non-specific immunity and anti-oxidation reactions for Pseudorasbora parva (PP) using dietary watermelon residue. The cumulative PP mortality and the pathogenic bacteria number in 15-45% groups reduced relative to those in control group (CK). Under 15-45% groups, AKP, ACP activities and akp, acp genes expression levels were increased markedly in nonspecific immunity system. Similarly, antioxidant response (SOD, CAT activities) and their genes was promoted also at 15-45% groups. Organic matter (vitamin and polyphenols) in watermelon residue improved AKP, ACP, SOD, CAT activities by increasing corresponding gene expressions. Theoretically, they could also function as stimulus signal, active center or composition to modulate enzyme activities and gene expressions. Besides, watermelon residue ameliorated NF-kB, mTOR responses pathway, and consequently suppressed Aeromonas hydrophila which augmented disease resistance. | 2021 | 34534653 |
| 8820 | 1 | 0.9986 | Multi-omics insights into the regulatory mechanism of citric acid in silage fermentation. A meta-analysis was conducted to assess the effects of citric acid (CA) on silage fermentation, and then used whole-plant cassava silage as a model to explore the underlying microbiological mechanisms with metagenomic and metabolomic data. The meta-analysis revealed that CA supplementation increased the dry matter, crude protein, water-soluble carbohydrate, and lactic acid contents in silage, but decreased the pH, dry matter loss, and the contents of fiber, NH(3)-N, and acetic acid, all of which meet the expectations for an ideal silage additive. The fermentation parameter responses of whole-plant cassava silage to CA were consistent with those in the meta-analysis. Metabolomic analysis revealed that CA increased the level of antimicrobial metabolites and decreased the level of amino acids and their derivatives in cassava silage. By constructing microbial genome and gene catalogs, we found that CA supplementation increased the abundance of lactic acid-rods (Levilactobacillus, Lentilactobacillus, and Companillactobacillus) and inhibited the abundance of lactic acid cocci (Leuconostoc, Pediococcus, and Weissella) and undesirable bacteria (Acinetobacter, Serratia, Klebsiella, and Pantoea), which resulted in an increased abundance of genes involved in structural carbohydrate hydrolysis (cellulase and pectinase), lactic acid production (ldh), and amino acid synthesis (CKase and CPS1) and a decreased abundance of genes involved in acetate (porA, acs, pdhC, and pct) and NH(3) production (glsA). Additionally, CA reduced the abundance of antibiotic resistance genes in silage by inhibiting the bacteria that hosted more resistance genes. Accordingly, CA supplementation could improve the nutritional value, preservation, and biosafety of silage by regulating its microbial composition and function. | 2025 | 40701415 |
| 8808 | 2 | 0.9984 | Phylogeny of nitrite reductase (nirK) and nitric oxide reductase (norB) genes from Nitrosospira species isolated from soil. Ammonia-oxidizing bacteria are believed to be an important source of the climatically important trace gas nitrous oxide (N(2)O). The genes for nitrite reductase (nirK) and nitric oxide reductase (norB), putatively responsible for nitrous oxide production, have been identified in several ammonia-oxidizing bacteria, but not in Nitrosospira strains that may dominate ammonia-oxidizing communities in soil. In this study, sequences from nirK and norB genes were detected in several cultured Nitrosospira species and the diversity and phylogeny of these genes were compared with those in other ammoniaoxidizing bacteria and in classical denitrifiers. The nirK and norB gene sequences obtained from Nitrosospira spp. were diverse and appeared to be less conserved than 16S rRNA genes and functional ammonia monooxygenase (amoA) genes. The nirK and norB genes from some Nitrosospira spp. were not phylogenetically distinct from those of denitrifiers, and phylogenetic analysis suggests that the nirK and norB genes in ammonia-oxidizing bacteria have been subject to lateral transfer. | 2007 | 17100985 |
| 8819 | 3 | 0.9984 | Responses of Bacillus sp. under Cu(II) stress in relation to extracellular polymeric substances and functional gene expression level. The production and composition of extracellular polymeric substances (EPS), as well as the EPS-related functional resistance genes and metabolic levels of Bacillus sp. under Cu(II) stress, were investigated. EPS production increased by 2.73 ± 0.29 times compared to the control when the strain was treated with 30 mg L(-1) Cu(II). Specifically, the polysaccharide (PS) content in EPS increased by 2.26 ± 0.28 g CDW(-1) and the PN/PS (protein/polysaccharide) ratio value increased by 3.18 ± 0.33 times under 30 mg L(-1) Cu(II) compared to the control. The increased EPS secretion and higher PN/PS ratio in EPS strengthened the cells' ability to resist the toxic effect of Cu(II). Differential expression of functional genes under Cu(II) stress was revealed by Gene Ontology pathway enrichment analysis and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analysis. The enriched genes were most obviously upregulated in the UMP biosynthesis pathway, the pyrimidine metabolism pathway, and the TCS metabolism pathway. This indicates an enhancement of EPS regulation-related metabolic levels and their role as a defense mechanism for cells to adapt to Cu(II) stress. Additionally, seven copper resistance genes were upregulated while three were downregulated. The upregulated genes were related to the heavy metal resistance, while downregulated genes were related to cell differentiation, indicating that the strain had initiated an obvious resistance to Cu(II) despite its severe cell toxicity. These results provided a basis for promoting EPS-regulated associated functional genes and the application of gene-regulated bacteria in heavy metal-containing wastewater treatment. | 2023 | 37195605 |
| 693 | 4 | 0.9984 | Effect of acid adaptation on the fate of Listeria monocytogenes in THP-1 human macrophages activated by gamma interferon. In Listeria monocytogenes the acid tolerance response (ATR) takes place through a programmed molecular response which ensures cell survival under unfavorable conditions. Much evidence links ATR with virulence, but the molecular determinants involved in the reactivity to low pHs and the behavior of acid-exposed bacteria within host cells are still poorly understood. We have investigated the effect of acid adaptation on the fate of L. monocytogenes in human macrophages. Expression of genes encoding determinants for cell invasion and intracellular survival was tested for acid-exposed bacteria, and invasive behavior in the human myelomonocytic cell line THP-1 activated with gamma interferon was assessed. Functional approaches demonstrated that preexposure to an acidic pH enhances the survival of L. monocytogenes in activated human macrophages and that this effect is associated with an altered pattern of expression of genes involved in acid resistance and cell invasion. Significantly decreased transcription of the plcA gene, encoding a phospholipase C involved in vacuolar escape and cell-to-cell spread, was observed in acid-adapted bacteria. This effect was due to a reduction in the quantity of the bicistronic plcA-prfA transcript, concomitant with an increase in the level(s) of the monocistronic prfA mRNA(s). The transcriptional shift from distal to proximal prfA promoters resulted in equal levels of the prfA transcript (and, as a consequence, of the inlA, hly, and actA transcripts) under neutral and acidic conditions. In contrast, the sodC and gad genes, encoding a cytoplasmic superoxide dismutase and the glutamate-based acid resistance system, respectively, were positively regulated at a low pH. Morphological approaches confirmed the increased intracellular survival and growth of acid-adapted L. monocytogenes cells both in vacuoles and in the cytoplasm of interferon gamma-activated THP-1 macrophages. Our data indicate that preexposure to a low pH has a positive impact on subsequent challenge of L. monocytogenes with macrophagic cells. | 2002 | 12117947 |
| 8766 | 5 | 0.9983 | Partitioning the Effects of Soil Legacy and Pathogen Exposure Determining Soil Suppressiveness via Induced Systemic Resistance. Beneficial host-associated bacteria can assist plant protection against pathogens. In particular, specific microbes are able to induce plant systemic resistance. However, it remains largely elusive which specific microbial taxa and functions trigger plant immune responses associated with disease suppression. Here, we experimentally studied this by setting up two independent microcosm experiments that differed in the time at which plants were exposed to the pathogen and the soil legacy (i.e., soils with historically suppressive or conducive). Overall, we found soil legacy effects to have a major influence on disease suppression irrespective of the time prior to pathogen exposure. Rhizosphere bacterial communities of tomato plants were significantly different between the two soils, with potential beneficial strains occurring at higher relative abundances in the suppressive soil. Root transcriptome analysis revealed the soil legacy to induce differences in gene expression, most importantly, genes involved in the pathway of phenylpropanoid biosynthesis. Last, we found genes in the phenylpropanoid biosynthesis pathway to correlate with specific microbial taxa, including Gp6, Actinomarinicola, Niastella, Phaeodactylibacter, Longimicrobium, Bythopirellula, Brevundimonas, Ferruginivarius, Kushneria, Methylomarinovum, Pseudolabrys, Sphingobium, Sphingomonas, and Alterococcus. Taken together, our study points to the potential regulation of plant systemic resistance by specific microbial taxa, and the importance of soil legacy on disease incidence and eliciting plant-defense mechanisms. | 2022 | 36365269 |
| 8700 | 6 | 0.9983 | Beneficial Endophytic Bacteria-Serendipita indica Interaction for Crop Enhancement and Resistance to Phytopathogens. Serendipita (=Piriformospora) indica is a fungal endophytic symbiont with the capabilities to enhance plant growth and confer resistance to different stresses. However, the application of this fungus in the field has led to inconsistent results, perhaps due to antagonism with other microbes. Here, we studied the impact of individual bacterial isolates from the endophytic bacterial community on the in vitro growth of S. indica. We further analyzed how combinations of bacteria and S. indica influence plant growth and protection against the phytopathogens Fusarium oxysporum and Rhizoctonia solani. Bacterial strains of the genera Bacillus, Enterobacter and Burkholderia negatively affected S. indica growth on plates, whereas Mycolicibacterium, Rhizobium, Paenibacillus strains and several other bacteria from different taxa stimulated fungal growth. To further explore the potential of bacteria positively interacting with S. indica, four of the most promising strains belonging to the genus Mycolicibacterium were selected for further experiments. Some dual inoculations of S. indica and Mycolicibacterium strains boosted the beneficial effects triggered by S. indica, further enhancing the growth of tomato plants, and alleviating the symptoms caused by the phytopathogens F. oxysporum and R. solani. However, some combinations of S. indica and bacteria were less effective than individual inoculations. By analyzing the genomes of the Mycolicibacterium strains, we revealed that these bacteria encode several genes predicted to be involved in the stimulation of S. indica growth, plant development and tolerance to abiotic and biotic stresses. Particularly, a high number of genes related to vitamin and nitrogen metabolism were detected. Taking into consideration multiple interactions on and inside plants, we showed in this study that some bacterial strains may induce beneficial effects on S. indica and could have an outstanding influence on the plant-fungus symbiosis. | 2019 | 31921065 |
| 7954 | 7 | 0.9983 | Metagenomic analysis reveals indole signaling effect on microbial community in sequencing batch reactors: Quorum sensing inhibition and antibiotic resistance enrichment. Indole is an essential signal molecule in microbial studies. However, its ecological role in biological wastewater treatments remains enigmatic. This study explores the links between indole and complex microbial communities using sequencing batch reactors exposed to 0, 15, and 150 mg/L indole concentrations. A concentration of 150 mg/L indole enriched indole degrader Burkholderiales, while pathogens, such as Giardia, Plasmodium, and Besnoitia were inhibited at 15 mg/L indole concentration. At the same time, indole reduced the abundance of predicted genes in the "signaling transduction mechanisms" pathway via the Non-supervised Orthologous Groups distributions analysis. Indole significantly decreased the concentration of homoserine lactones, especially C(14)-HSL. Furthermore, the quorum-sensing signaling acceptors containing LuxR, the dCACHE domain, and RpfC showed negative distributions with indole and indole oxygenase genes. Signaling acceptors' potential origins were mainly Burkholderiales, Actinobacteria, and Xanthomonadales. Meanwhile, concentrated indole (150 mg/L) increased the total abundance of antibiotic resistance genes by 3.52 folds, especially on aminoglycoside, multidrug, tetracycline, and sulfonamide. Based on Spearman's correlation analysis, the homoserine lactone degradation genes which were significantly impacted by indole negatively correlated with the antibiotic resistance gene abundance. This study brings new insights into the effect of indole signaling on in biological wastewater treatment plants. | 2023 | 37054839 |
| 7953 | 8 | 0.9983 | Rapid impact of phenanthrene and arsenic on bacterial community structure and activities in sand batches. The impact of both organic and inorganic pollution on the structure of soil microbial communities is poorly documented. A short-time batch experiment (6 days) was conducted to study the impact of both types of pollutants on the taxonomic, metabolic and functional diversity of soil bacteria. For this purpose sand spiked with phenanthrene (500 mg kg(-1) sand) or arsenic (arsenite 0.66 mM and arsenate 12.5 mM) was supplemented with artificial root exudates and was inoculated with bacteria originated from an aged PAH and heavy-metal-polluted soil. The bacterial community was characterised using bacterial strain isolation, TTGE fingerprinting and proteomics. Without pollutant, or with phenanthrene or arsenic, there were no significant differences in the abundance of bacteria and the communities were dominated by Pseudomonas and Paenibacillus genera. However, at the concentrations used, both phenanthrene or arsenic were toxic as shown by the decrease in mineralisation activities. Using community-level physiological profiles (Biolog Ecoplates™) or differential proteomics, we observed that the pollutants had an impact on the community physiology, in particular phenanthrene induced a general cellular stress response with changes in the central metabolism and membrane protein synthesis. Real-time PCR quantification of functional genes and transcripts revealed that arsenic induced the transcription of functional arsenic resistance and speciation genes (arsB, ACR3 and aioA), while no transcription of PAH-degradation genes (PAH-dioxygenase and catechol-dioxygenase) was detected with phenanthrene. Altogether, in our tested conditions, pollutants do not have a major effect on community abundance or taxonomic composition but rather have an impact on metabolic and functional bacterial properties. | 2014 | 24189653 |
| 8793 | 9 | 0.9983 | Enhanced Phytopathogen Biofilm Control in the Soybean Phyllosphere by the Phoresy of Bacteriophages Hitchhiking on Biocontrol Bacteria. Phage-based biocontrol has shown notable advantages in protecting plants against pathogenic bacteria in agricultural settings compared to chemical-based bactericides. However, the efficiency and scope of phage biocontrol of pathogenic bacteria are limited by the intrinsic properties of phages. Here, we investigated pathogen biofilm eradication in the phyllosphere using the phoresy system of hitchhiking phages onto carrier biocontrol bacteria. The phoresy system efficiently removed the pathogen biofilm in the soybean phyllosphere, reducing the total biomass by 58% and phytopathogens by 82% compared to the untreated control. Biofilm eradication tests demonstrated a significant combined beneficial effect (Bliss independence model, CI < 1) as phages improved carrier bacteria colonization by 1.2-fold and carrier bacteria facilitated phage infection by 1.4-fold. Transcriptomic analysis showed that phoresy significantly enhanced motility (e.g., fliC and pilD genes) and energy metabolism (e.g., pgm and pgk genes) of carrier bacteria and suppressed the defense system (e.g., MSH3 and FLS2 genes) and energy metabolism (e.g., petB and petC genes) of pathogens. Metabolomics analysis revealed that the phoresy system stimulated the secretion of beneficial metabolites (e.g., flavonoid and tropane alkaloid) that could enhance stress response and phyllosphere protection in soybeans. Overall, the phoresy of phages hitchhiking on biocontrol bacteria offers a novel and effective strategy for phyllosphere microbiome manipulation and bacterial disease control. | 2025 | 40315344 |
| 158 | 10 | 0.9983 | Homology- and cross-resistance of Lactobacillus plantarum to acid and osmotic stress and the influence of induction conditions on its proliferation by RNA-Seq. In this study, homology- and cross-resistance of Lactobacillus plantarum L1 and Lactobacillus plantarum L2 to acid and osmotic stress were investigated. Meanwhile, its proliferation mechanism was demonstrated by transcriptomic analysis using RNA sequencing. We found that the homologous-resistance and cross-resistance of L. plantarum L1 and L. plantarum L2 increased after acid and osmotic induction treatment by lactic acid and sodium lactate solution in advance, and the survival rate of live bacteria was improved. In addition, the count of viable bacteria of L. plantarum L2 significantly increased cultivated at a pH 5.0 with a 15% sodium lactate sublethal treatment, compared with the control group. Further study revealed that genes related to membrane transport, amino acid metabolism, nucleotide metabolism, and cell growth were significantly upregulated. These findings will contribute to promote high-density cell culture of starter cultures production in the fermented food industry. | 2021 | 33945164 |
| 145 | 11 | 0.9983 | Microbial Resistance Mechanisms to the Antibiotic and Phytotoxin Fusaric Acid. Fusaric acid (FA) produced by Fusarium oxysporum plays an important role in disease development in plants, including cotton. This non-specific toxin also has antibiotic effects on microorganisms. Thus, one expects a potential pool of diverse detoxification mechanisms of FA in nature. Bacteria and fungi from soils infested with Fusarium and from laboratory sources were evaluated for their ability to grow in the presence of FA and to alter the structure of FA into less toxic compounds. None of the bacterial strains were able to chemically modify FA. Highly FA-resistant strains were found only in Gram-negative bacteria, mainly in the genus of Pseudomonas. The FA resistance of the Gram-negative bacteria was positively correlated with the number of predicted genes for FA efflux pumps present in the genome. Phylogenetic analysis of predicted FA resistance proteins (FUSC, an inner membrane transporter component of the efflux pump) revealed that FUSC proteins having high sequence identities with the functionally characterized FA resistance protein FusC or Fdt might be the major contributors of FA resistance. In contrast, most fungi converted FA to less toxic compounds regardless of the level of FA resistance they exhibited. Five derivatives were detected, and the detoxification of FA involved either oxidative reactions on the butyl side chain or reductive reactions on the carboxylic acid group. The production of these metabolites from widely different phyla indicates that resistance to FA by altering its structure is highly conserved. A few FA resistant saprophytic or biocontrol strains of fungi were incapable of altering FA, indicating a possible involvement of efflux transporters. Deployment of both efflux and derivatization mechanisms may be a common feature of fungal FA resistance. | 2017 | 28986689 |
| 8769 | 12 | 0.9983 | Transgenic soybean of GsMYB10 shapes rhizosphere microbes to promote resistance to aluminum (Al) toxicity. Plant resistance genes could affect rhizosphere microbiota, which in turn enhanced plant resistance to stresses. Our previous study found that overexpression of the GsMYB10 gene led to enhanced tolerance of soybean plants to aluminum (Al) toxicity. However, whether GsMYB10 gene could regulate rhizosphere microbiota to mitigate Al toxicity remains unclear. Here, we analyzed the rhizosphere microbiomes of HC6 soybean (WT) and transgenic soybean (trans-GsMYB10) at three Al concentrations, and constructed three different synthetic microbial communities (SynComs), including bacterial, fungal and cross-kingdom (bacteria and fungi) SynComs to verify their role in improving Al tolerance of soybean. Trans-GsMYB10 shaped the rhizosphere microbial communities and harbored some beneficial microbes, such as Bacillus, Aspergillus and Talaromyces under Al toxicity. Fungal and cross-kingdom SynComs showed a more effective role than the bacterial one in resistance to Al stress, and these SynComs helped soybean resist Al toxicity via affecting some functional genes that involved cell wall biosynthesis and organic acid transport etc. Overall, this study reveals the mechanism of soybean functional genes regulating the synergistic resistance of rhizosphere microbiota and plants to Al toxicity, and also highlights the possibility of focusing on the rhizobial microbial community as a potential molecular breeding target to produce crops. | 2023 | 37187122 |
| 8699 | 13 | 0.9983 | Hordeum vulgare differentiates its response to beneficial bacteria. BACKGROUND: In nature, beneficial bacteria triggering induced systemic resistance (ISR) may protect plants from potential diseases, reducing yield losses caused by diverse pathogens. However, little is known about how the host plant initially responds to different beneficial bacteria. To reveal the impact of different bacteria on barley (Hordeum vulgare), bacterial colonization patterns, gene expression, and composition of seed endophytes were explored. RESULTS: This study used the soil-borne Ensifer meliloti, as well as Pantoea sp. and Pseudomonas sp. isolated from barley seeds, individually. The results demonstrated that those bacteria persisted in the rhizosphere but with different colonization patterns. Although root-leaf translocation was not observed, all three bacteria induced systemic resistance (ISR) against foliar fungal pathogens. Transcriptome analysis revealed that ion- and stress-related genes were regulated in plants that first encountered bacteria. Iron homeostasis and heat stress responses were involved in the response to E. meliloti and Pantoea sp., even if the iron content was not altered. Heat shock protein-encoding genes responded to inoculation with Pantoea sp. and Pseudomonas sp. Furthermore, bacterial inoculation affected the composition of seed endophytes. Investigation of the following generation indicated that the enhanced resistance was not heritable. CONCLUSIONS: Here, using barley as a model, we highlighted different responses to three different beneficial bacteria as well as the influence of soil-borne Ensifer meliloti on the seed microbiome. In total, these results can help to understand the interaction between ISR-triggering bacteria and a crop plant, which is essential for the application of biological agents in sustainable agriculture. | 2023 | 37789272 |
| 7639 | 14 | 0.9983 | Structural and Functional Changes of Groundwater Bacterial Community During Temperature and pH Disturbances. In this study, we report the characteristics of a microbial community in sampled groundwater and elucidate the effects of temperature and pH disturbances on bacterial structure and nitrogen-cycling functions. The predominant phyla of candidate OD1, candidate OP3, and Proteobacteria represented more than half of the total bacteria, which clearly manifested as a "low nucleic acid content (LNA) bacteria majority" type via flow cytometric fingerprint. The results showed that LNA bacteria were more tolerant to rapid changes in temperature and pH, compared to high nucleic acid content (HNA) bacteria. A continuous temperature increase test demonstrated that the LNA bacterial group was less competitive than the HNA bacterial group in terms of maintaining their cell intactness and growth potential. In contrast, the percentage of intact LNA bacteria was maintained at nearly 70% with pH decrease, despite a 50% decrease in total intact cells. Next-generation sequencing results revealed strong resistance and growth potential of phylum Proteobacteria when the temperature increased or the pH decreased in groundwater, especially for subclasses α-, β-, and γ-Proteobacteria. In addition, relative abundance of nitrogen-related functional genes by qPCR showed no difference in nitrifiers or denitrifiers within 0.45 μm-captured and 0.45 μm-filterable bacteria due to phylogenetic diversity. One exception was the monophyletic anammox bacteria that belong to the phylum Planctomycetes, which were mostly captured on a 0.45-μm filter. Furthermore, we showed that both temperature increase and pH decrease could enhance the denitrification potential, whereas the nitrification and anammox potentials were weakened. | 2019 | 30706112 |
| 8148 | 15 | 0.9983 | Methylobacterium-plant interaction genes regulated by plant exudate and quorum sensing molecules. Bacteria from the genus Methylobacterium interact symbiotically (endophytically and epiphytically) with different plant species. These interactions can promote plant growth or induce systemic resistance, increasing plant fitness. The plant colonization is guided by molecular communication between bacteria-bacteria and bacteria-plants, where the bacteria recognize specific exuded compounds by other bacteria (e.g. homoserine molecules) and/or by the plant roots (e.g. flavonoids, ethanol and methanol), respectively. In this context, the aim of this study was to evaluate the effect of quorum sensing molecules (N-acyl-homoserine lactones) and plant exudates (including ethanol) in the expression of a series of bacterial genes involved in Methylobacterium-plant interaction. The selected genes are related to bacterial metabolism (mxaF), adaptation to stressful environment (crtI, phoU and sss), to interactions with plant metabolism compounds (acdS) and pathogenicity (patatin and phoU). Under in vitro conditions, our results showed the differential expression of some important genes related to metabolism, stress and pathogenesis, thereby AHL molecules up-regulate all tested genes, except phoU, while plant exudates induce only mxaF gene expression. In the presence of plant exudates there is a lower bacterial density (due the endophytic and epiphytic colonization), which produce less AHL, leading to down regulation of genes when compared to the control. Therefore, bacterial density, more than plant exudate, influences the expression of genes related to plant-bacteria interaction. | 2013 | 24688531 |
| 8313 | 16 | 0.9982 | Mechanism of biofilm-mediated stress resistance and lifespan extension in C. elegans. Bacteria naturally form communities of cells known as biofilms. However the physiological roles of biofilms produced by non-pathogenic microbiota remain largely unknown. To assess the impact of a biofilm on host physiology we explored the effect of several non-pathogenic biofilm-forming bacteria on Caenorhabditis elegans. We show that biofilm formation by Bacillus subtilis, Lactobacillus rhamnosus and Pseudomonas fluorescens induces C. elegans stress resistance. Biofilm also protects against pathogenic infection and prolongs lifespan. Total mRNA analysis identified a set of host genes that are upregulated in response to biofilm formation by B. subtilis. We further demonstrate that mtl-1 is responsible for the biofilm-mediated increase in oxidative stress resistance and lifespan extension. Induction of mtl-1 and hsp-70 promotes biofilm-mediated thermotolerance. ilys-2 activity accounts for biofilm-mediated resistance to Pseudomonas aeruginosa killing. These results reveal the importance of non-pathogenic biofilms for host physiology and provide a framework to study commensal biofilms in higher organisms. | 2017 | 28769037 |
| 685 | 17 | 0.9982 | Implication of a Key Region of Six Bacillus cereus Genes Involved in Siroheme Synthesis, Nitrite Reductase Production and Iron Cluster Repair in the Bacterial Response to Nitric Oxide Stress. Bacterial response to nitric oxide (NO) is of major importance for bacterial survival. NO stress is a main actor of the eukaryotic immune response and several pathogenic bacteria have developed means for detoxification and repair of the damages caused by NO. However, bacterial mechanisms of NO resistance by Gram-positive bacteria are poorly described. In the opportunistic foodborne pathogen Bacillus cereus, genome sequence analyses did not identify homologs to known NO reductases and transcriptional regulators, such as NsrR, which orchestrate the response to NO of other pathogenic or non-pathogenic bacteria. Using a transcriptomic approach, we investigated the adaptation of B. cereus to NO stress. A cluster of 6 genes was identified to be strongly up-regulated in the early phase of the response. This cluster contains an iron-sulfur cluster repair enzyme, a nitrite reductase and three enzymes involved in siroheme biosynthesis. The expression pattern and close genetic localization suggest a functional link between these genes, which may play a pivotal role in the resistance of B. cereus to NO stress during infection. | 2021 | 34064887 |
| 596 | 18 | 0.9982 | Non-selective regulation of peroxide and superoxide resistance genes by PerR in Campylobacter jejuni. Campylobacter jejuni is an important foodborne pathogen. The molecular mechanisms for the regulation of oxidative stress resistance have not yet been understood fully in this bacterium. In this study, we investigated how PerR (peroxide stress regulator) modulates the transcriptional regulation of both peroxide and superoxide resistance genes in C. jejuni, particularly under oxidative stress conditions. The transcriptional levels of ahpC, katA, and sodB were substantially increased by aeration and oxidant exposure. Interestingly, a perR mutation completely abrogated the transcriptional response of ahpC, katA and sodB to oxidants. Furthermore, we demonstrated that perR transcription was reduced by aeration and oxidant exposure. In contrast to the unique role of PerR homologs in peroxide stress regulation in other bacteria, C. jejuni PerR directly regulates the transcription of sodB, the most important gene in superoxide defense, as evidenced by the alteration of sodB transcription by the perR mutation and direct binding of rPerR to the sodB promoter. In addition, we also observed notable morphological changes in C. jejuni from spiral rods to cocoid morphology under aerobic conditions. Based on the intracellular ATP levels, C. jejuni entered a viable-but-non-culturable (VBNC) state under aerobic conditions. These findings clearly demonstrate that C. jejuni possesses a unique regulatory mechanism of oxidative stress defense that does not specifically distinguish between peroxide and superoxide defense, and PerR plays a pivotal role in this non-selective regulation of oxidative stress resistance in C. jejuni. | 2015 | 25741333 |
| 8767 | 19 | 0.9982 | Poly-γ-glutamic acid enhanced the drought resistance of maize by improving photosynthesis and affecting the rhizosphere microbial community. BACKGROUND: Compared with other abiotic stresses, drought stress causes serious crop yield reductions. Poly-γ-glutamic acid (γ-PGA), as an environmentally friendly biomacromolecule, plays an important role in plant growth and regulation. RESULTS: In this project, the effect of exogenous application of γ-PGA on drought tolerance of maize (Zea mays. L) and its mechanism were studied. Drought dramatically inhibited the growth and development of maize, but the exogenous application of γ-PGA significantly increased the dry weight of maize, the contents of ABA, soluble sugar, proline, and chlorophyll, and the photosynthetic rate under severe drought stress. RNA-seq data showed that γ-PGA may enhance drought resistance in maize by affecting the expression of ABA biosynthesis, signal transduction, and photosynthesis-related genes and other stress-responsive genes, which was also confirmed by RT-PCR and promoter motif analysis. In addition, diversity and structure analysis of the rhizosphere soil bacterial community demonstrated that γ-PGA enriched plant growth promoting bacteria such as Actinobacteria, Chloroflexi, Firmicutes, Alphaproteobacteria and Deltaproteobacteria. Moreover, γ-PGA significantly improved root development, urease activity and the ABA contents of maize rhizospheric soil under drought stress. This study emphasized the possibility of using γ-PGA to improve crop drought resistance and the soil environment under drought conditions and revealed its preliminary mechanism. CONCLUSIONS: Exogenous application of poly-γ-glutamic acid could significantly enhance the drought resistance of maize by improving photosynthesis, and root development and affecting the rhizosphere microbial community. | 2022 | 34979944 |