# | Rank | Similarity | Title + Abs. | Year | PMID |
|---|---|---|---|---|---|
| 0 | 1 | 2 | 3 | 4 | 5 |
| 6022 | 0 | 0.9961 | Bile Salt Hydrolase Degrades β-Lactam Antibiotics and Confers Antibiotic Resistance on Lactobacillus paragasseri. Bile salt hydrolase (BSH) is a well-characterized probiotic enzyme associated with bile detoxification and colonization of lactic acid bacteria in the human gastrointestinal tract. Here, we isolated a putative BSH (LpBSH) from the probiotic bacterium Lactobacillus paragasseri JCM 5343(T) and demonstrated its bifunctional activity that allows it to degrade not only bile salts but also the antibiotic (penicillin). Although antibiotic resistance and bile detoxification have been separately recognized as different microbial functions, our findings suggest that bifunctional BSHs simultaneously confer ecological advantages to host gut bacteria to improve their survival in the mammalian intestine by attaining a high resistance to bile salts and β-lactams. Strain JCM 5343(T) showed resistance to both bile salts and β-lactam antibiotics, suggesting that LpBSH may be involved in this multi-resistance of the strain. We further verified that such bifunctional enzymes were broadly distributed among the phylogeny, suggesting that the bifunctionality may be conserved in other BSHs of gut bacteria. This study revealed the physiological role and phylogenetic diversity of bifunctional enzymes degrading bile salts and β-lactams in gut bacteria. Furthermore, our findings suggest that the hitherto-overlooked penicillin-degrading activity of penicillin acylase could be a potential new target for the probiotic function of gut bacteria. | 2022 | 35733973 |
| 3582 | 1 | 0.9960 | Investigating the transmissibility of tet(W) in bifidobacteria exposed to acid and bile stress. Transfer of antibiotic resistance genes from probiotic bacteria to pathogens poses a safety concern. Orally administered probiotics are exposed to stressful conditions during gastrointestinal transit. In this study, filter mating experiments were performed to investigate the potential role of exposure of Bifidobacterium isolates to acid and bile stress on the transfer of a tetracycline resistance gene, tet(W), to Enterococcus faecalis ATCC 51299. No E. faecalis transconjugants were obtained after mating with either stressed or unstressed Bifidobacterium, thereby suggesting that tet(W) could not be transferred as a result of exposure to gastrointestinal stresses. | 2018 | 29662736 |
| 340 | 2 | 0.9959 | Study of MFD-type repair in locus determining resistance of Escherichia coli to streptomycin. The yield of induced mutations to streptomycin resistance (Str) in E. coli, UV-irradiated and temporarily incubated in liquid medium not permitting protein synthesis, depends upon the conditions of preirradiation growth and preirradiation treatment of the bacteria, i.e. on their physiological state at the moment of irradiation. This fact is not readily reconciled with a model postulating mutation production in the structural genes of E. coli during excision repair. A preferred explanation is offered, based on the assumption that the efficiency of mutagenesis at the rpsL (strA) locus is determined by interference of antimutagenic (generalized excision repair and MFD) and promutagenic (mutation fixation of excision repair) events. The participation of macromolecular syntheses in Str mutation fixation is suggested. | 1986 | 3537780 |
| 6019 | 3 | 0.9959 | Effects of Lactobacillus pentosus combined with Arthrospira platensis on the growth performance, immune response, and intestinal microbiota of Litopenaeus vannamei. Litopenaeus vannamei is one of the most productive shrimp species in the world. However, shrimp farming is suffering from adverse environmental conditions and disease outbreaks. Typically, Lactobacillus pentosus and Arthrospira platensis are used as substitutes for some antibiotics. In the present study, we assessed the effects of dietary supplements along with living bacteria or cell-free extracts of L. pentosus combined with A. platensis on the growth performance, immune response, intestinal microbiota, and disease resistance of L. vannamei against Vibrio alginolyticus. Shrimp fed L. pentosus live bacteria combined with A. platensis showed the best growth performance and lowest feed conversion rate. The supplementation diet with L. pentosus live bacteria and A. platensis could significantly enhance the trypsin activity in shrimp after the feeding trial. Given the lowest feed conversion rate in shrimp fed L. pentosus live bacteria combined with A. platensis, we reasonably speculated that the decrease in feed conversion rate may be related to the increase in trypsin activity. In addition, dietary cell-free extracts of L. pentosus combined with A. platensis enhanced the expression of immune-related genes after the feeding trial or challenge test. Moreover, results of the bacterial challenge test indicated that the shrimp fed cell-free extracts of L. pentosus combined with A. platensis diet resulted in the highest survival rate, which suggested that cell-free extracts of L. pentosus and A. platensis could improve the disease resistance against V. alginolyticus by up-regulating the expressions of immune-related genes. Dietary L.pentosus or A. platensis, or their combination, reduced the abundance of harmful bacteria, including Proteobacteria in shrimp intestine, which suggested that L. pentosus and A. platensis could improve the growth performance and health of shrimp by regulating the structure of the intestinal microbiota. The findings of this study demonstrated that L. pentosus live bacteria and A. platensis exerted synergistic effects on the growth performance and digestion in shrimp, while cell-free extracts of L. pentosus and A. platensis showed synergistic effects on the immune response and disease resistance of shrimp against V. alginolyticus. | 2022 | 34883257 |
| 6168 | 4 | 0.9959 | SdiA aids enterohemorrhagic Escherichia coli carriage by cattle fed a forage or grain diet. Enterohemorrhagic Escherichia coli (EHEC) causes hemorrhagic colitis and life-threatening complications. The main reservoirs for EHEC are healthy ruminants. We reported that SdiA senses acyl homoserine lactones (AHLs) in the bovine rumen to activate expression of the glutamate acid resistance (gad) genes priming EHEC's acid resistance before they pass into the acidic abomasum. Conversely, SdiA represses expression of the locus of enterocyte effacement (LEE) genes, whose expression is not required for bacterial survival in the rumen but is necessary for efficient colonization at the rectoanal junction (RAJ) mucosa. Our previous studies show that SdiA-dependent regulation was necessary for efficient EHEC colonization of cattle fed a grain diet. Here, we compared the SdiA role in EHEC colonization of cattle fed a forage hay diet. We detected AHLs in the rumen of cattle fed a hay diet, and these AHLs activated gad gene expression in an SdiA-dependent manner. The rumen fluid and fecal samples from hay-fed cattle were near neutrality, while the same digesta samples from grain-fed animals were acidic. Cattle fed either grain or hay and challenged with EHEC orally carried the bacteria similarly. EHEC was cleared from the rumen within days and from the RAJ mucosa after approximately one month. In competition trials, where animals were challenged with both wild-type and SdiA deletion mutant bacteria, diet did not affect the outcome that the wild-type strain was better able to persist and colonize. However, the wild-type strain had a greater advantage over the SdiA deletion mutant at the RAJ mucosa among cattle fed the grain diet. | 2013 | 23836826 |
| 236 | 5 | 0.9958 | Glutamate decarboxylase-dependent acid resistance in orally acquired bacteria: function, distribution and biomedical implications of the gadBC operon. For successful colonization of the mammalian host, orally acquired bacteria must overcome the extreme acidic stress (pH < 2.5) encountered during transit through the host stomach. The glutamate-dependent acid resistance (GDAR) system is by far the most potent acid resistance system in commensal and pathogenic Escherichia coli, Shigella flexneri, Listeria monocytogenes and Lactococcus lactis. GDAR requires the activity of glutamate decarboxylase (GadB), an intracellular PLP-dependent enzyme which performs a proton-consuming decarboxylation reaction, and of the cognate antiporter (GadC), which performs the glutamatein /γ-aminobutyrateout (GABA) electrogenic antiport. Herein we review recent findings on the structural determinants responsible for pH-dependent intracellular activation of E. coli GadB and GadC. A survey of genomes of bacteria (pathogenic and non-pathogenic), having in common the ability to colonize or to transit through the host gut, shows that the gadB and gadC genes frequently lie next or near each other. This gene arrangement is likely to be important to ensure timely co-regulation of the decarboxylase and the antiporter. Besides the involvement in acid resistance, GABA production and release were found to occur at very high levels in lactic acid bacteria originally isolated from traditionally fermented foods, supporting the evidence that GABA-enriched foods possess health-promoting properties. | 2012 | 22995042 |
| 6170 | 6 | 0.9958 | Resistance and susceptibility of mice to bacterial infection. IV. Functional specificity in natural resistance to facultative intracellular bacteria. The effect of opsonic antibody on resistance of susceptibility of three strains of mice, C57Bl/10, BALB/c, and CBA to the intracellular bacteria Listeria monocytogenes, Salmonella typhimurium, and Brucella abortus was tested. Bacteria were opsonized by serum treatment before their injection into mice, or the mice were preimmunized by injection with alcohol killed bacteria which induces antibody without macrophage activation. Antibody did not increase the rate of clearance of Listeria from the bloodstream, nor did it affect the subsequent growth of that organism in the spleen and liver. Blood clearance of S. typhimurium and of B. abortus was increased by preopsonization with specific antibody, indicating that opsonins were a limiting factor in resistance to these two bacteria. However, neither opsonization before infection nor immunization with alcohol killed vaccines had any effect on the strain distribution of resistance/susceptibility, which differs for each of the three intracellular pathogens. Thus, even in the presence of adequate opsonization the three strains of mice showed different patterns of resistance/susceptibility to Listeria, S. typhimurium, and B. abortus. This implies that each has a unique cellular mechanism of early nonspecific resistance. | 1983 | 6413682 |
| 6023 | 7 | 0.9958 | Bile-inducible efflux transporter from Bifidobacterium longum NCC2705, conferring bile resistance. Bifidobacteria are normal inhabitants of the human gut. Some strains of this genus are considered health promoting or probiotic, being included in numerous food products. In order to exert their health benefits, these bacteria must overcome biological barriers, including bile salts, to colonize and survive in specific parts of the intestinal tract. The role of multidrug resistance (MDR) transporters in bile resistance of probiotic bacteria and the effect of bile on probiotic gene expression are not fully understood. In the present study, the effect of subinhibitory concentrations of bile on the expression levels of predicted MDR genes from three different bifidobacterial strains, belonging to Bifidobacterium longum subsp. longum, Bifidobacterium breve, and Bifidobacterium animalis subsp. lactis, was tested. In this way, two putative MDR genes whose expression was induced by bile, BL0920 from B. longum and its homolog, Bbr0838, from B. breve, were identified. The expression of the BL0920 gene in Escherichia coli was shown to confer resistance to bile, likely to be mediated by active efflux from the cells. To the best of our knowledge, this represents the first identified bifidobacterial bile efflux pump whose expression is induced by bile. | 2009 | 19304838 |
| 6040 | 8 | 0.9957 | Investigating the antibacterial effects of some Lactobacillus, Bifidobacterium and acetobacter strains killed by different methods on Streptococcus mutans and Escherichia coli. Although there are many health advantages assigned to different live bacteria such as probiotics, some health threatening effects have also been reported. For example, live bacteria can transfer antibiotic resistance genes to other commensal and opportunistic bacteria of gastrointestinal tract. Recently, it was shown that using killed bacteria have some advantages over live ones. In this research, heat, paraformaldehyde and ozone killing methods were used to kill the bacteria. Acetobacter cerevisiae, Lactobacillus acidophilus, Bifidobacterium lactis and traditional vinegar and fermented dairy product (Kumeh) derived bacteria were killed and their antibacterial activity against Streptococcus mutans and Escherichia coli was investigated. To identify the bacteria isolated from the traditional products, 16S rDNA gene was partially sequenced. The gene analysis showed vinegar and Kumeh derived bacteria were Acetobacter pasteurianus and Lactobacillus crustorum (LcK) strains respectively. The S. mutans growth inhibition was detected in the all concentrations of all killed samples. However, generally, E. coli showed more resistant to the killed bacteria than S. mutans and the antibacterial effect of heat-killed bacteria against E. coli was not observed in the all concentrations for some killed bacteria. Among the pathogenic bacteria, S. mutans was the most sensitive one to the killed bacteria with 70% of reduction in its viability. In conclusion, this research showed that different killed bacteria had different effects on other bacteria and the killing method showed an impact on these effects. Overall, paraformaldehyde-killed L.crustorum (LcK) showed the best antibacterial activity against S. mutans; about 70% decrease in bacterial viability. | 2019 | 31998811 |
| 6200 | 9 | 0.9957 | Heterologous expression of bacterial and human multidrug resistance proteins protect Escherichia coli against mercury and zinc contamination. In order to determine the role of multidrug resistance proteins in mercury and zinc resistance, human MDR1, Lactococcus lactis lmrA, and Oenococcus oeni omrA genes were expressed in an Escherichia coli tolC mutant which is hypersensitive to metals. The three transporters conferred an increased mercury and zinc resistance to E. coli as compared to the control bacteria. This improved resistance correlated with a decreased zinc and mercury bioaccumulation. Indeed, quantification of intracellular metal concentrations by atomic absorption spectrometry (AAS) showed a 2.1-, 3-, and 5.1-fold decrease in zinc in cells expressing hMDR1, omrA, and lmrA, respectively, and a 2.7-, 7.5-, and 7.7-fold decrease in mercury in cells expressing omrA, lmrA, and hMDR1, respectively, as compared to the control bacteria. This means that hMDR1, LmrA, and OmrA proteins which are specialised in xenobiotic scavenging, their main known function, are nevertheless able to confer some resistance against metals. Our results show that the tolC mutated strain is well adapted to the study of MDR transporter activity and could be used to screen substrates and competitive hMDR1 inhibitors. | 2006 | 16703280 |
| 342 | 10 | 0.9957 | Heat-shock-increased survival to far-UV radiation in Escherichia coli is wavelength dependent. Heat-shock-induced resistance to far-UV (FUV) radiation was studied in Escherichia coli. The induction of FUV resistance was shown to be dependent on the products of the genes uvrA and polA in bacteria irradiated at 254 nm. Heat shock increased the resistance to 280 nm radiation in a uvrA6 recA13 mutant. Heat shock lowered the mutation frequency (reversion to tryptophan proficiency) in wild-type or uvrA strains irradiated at 254 nm. When these strains were irradiated at 280 nm, heat shock did not interfere with the mutation frequency in the wild-type strain, but greatly enhanced mutations in the uvrA mutant. After heat-shock treatment, the wild-type strain irradiated at 254 nm showed increased DNA degradation, indicating enhanced repair activity. However, heat shock did not stimulate SOS repair triggered by FUV. An increased survival of bacteriophages irradiated with FUV and inoculated into heat-shock-treated bacteria was not detected. The possibility that heat shock enhances excision repair activity in a wavelength-dependent manner is discussed. | 1994 | 8176549 |
| 717 | 11 | 0.9957 | Sodium regulates Escherichia coli acid resistance, and influences GadX- and GadW-dependent activation of gadE. Enteric bacteria must survive the extreme acid of the stomach (pH 2 or less) before entering the intestine where they can colonize and cause disease. Escherichia coli is superior to most other Enterobacteriaceae in surviving pH 2 acid stress because it has four known acid-resistance systems, the most studied of which depends on glutamic acid. Glutamate-dependent acid resistance requires glutamate decarboxylase isozymes GadA and GadB, as well as a glutamate/gamma-aminobutyric acid antiporter encoded by gadC. The regulatory protein GadE is the essential activator of the gadA and gadBC genes. The transcription of gadE, however, is controlled by numerous proteins. Two of these proteins, GadX and GadW, are AraC-family regulators whose sensory input signals are not known. Since Na(+) and K(+) play important roles in pH homeostasis, the contribution of these ions toward the regulation of this acid-resistance system was examined. The results indicated that a decrease in Na(+), but not K(+), concentration coincided with diminished acid resistance, and decreased expression of the gadE, gadA and gadBC genes. However, Na(+)-dependent regulation of these genes dissipated in the absence of GadX and GadW. Since Na(+) levels did not regulate gadX or gadW transcription, it is proposed that GadX and GadW sense intracellular Na(+) concentration or some consequence of altered Na(+) levels. | 2007 | 17768258 |
| 6357 | 12 | 0.9957 | Cloning and expression of the pediocin operon in Streptococcus thermophilus and other lactic fermentation bacteria. Production of pediocin in Pediococcus acidilactici is associated with pMBR1.0, which encodes prepediocin, a pediocin immunity protein, and two proteins involved in secretion and precursor processing. These four genes are organized as an operon under control of a single promoter. We have constructed shuttle vectors that contain all four structural genes, the chromosomal promoter ST(P2201) from Streptococcus thermophilus, and repA from the 2-kbp S. thermophilus plasmid pER8. The recombinant plasmid, pPC318, expressed and secreted active pediocin in Escherichia coli. Streptococcus thermophilus, Lactococcus lactis subsp. lactis, and Enterococcus faecalis were electrotransformed with pPC418, a modified vector fitted with an erythromycin resistance tracking gene. Pediocin was produced and secreted in each of the lactic acid bacteria, and production was stable for up to ten passages. The expression of pediocin in dairy fermentation microbes has important implications for bacteriocins as food preservatives in dairy products. | 1999 | 10489440 |
| 6199 | 13 | 0.9956 | A bacterial gene homologous to ABC transporters protect Oenococcus oeni from ethanol and other stress factors in wine. The wine lactic acid bacteria Oenococcus oeni has to cope with harsh environmental conditions including an acidic pH, a high alcoholic content, non-optimal growth temperatures, and growth inhibitory compounds such as fatty acids, phenolic acids and tannins. We here describe characterisation and cloning of the O. oeni omrA gene encoding a protein belonging to the ATP-binding cassette superfamily of transporters. The OmrA protein displays the highest sequence similarity with the subfamily of ATP-dependent multidrug resistance (MDR) proteins, most notably the bacterial Lactococcus lactis LmrA homologue of the human MDR1 P-glycoprotein. The omrA gene proved to be a stress-responsive gene since its expression was increased at high temperature or under osmotic shock. The OmrA protein function was tested in Escherichia coli, and consistent with the omrA gene expression pattern, OmrA conferred protection to bacteria grown on a high salt medium. OmrA also triggered bacterial resistance to sodium laurate, wine and ethanol toxicity. The homologous LmrA protein featured the same stress-protective pattern than OmrA when expressed in E. coli, and the contribution to resistance of both OmrA and LmrA transporters was decreased by verapamil, a well-known inhibitor of the human MDR1 protein. Genes homologous to omrA were detected in other wine lactic acid bacteria, suggesting that this type of genes might constitute a well-conserved stress-protective molecular device. | 2004 | 15033264 |
| 6230 | 14 | 0.9956 | dpr and sod in Streptococcus mutans are involved in coexistence with S. sanguinis, and PerR is associated with resistance to H2O2. Large numbers of bacteria coexist in the oral cavity. Streptococcus sanguinis, one of the major bacteria in dental plaque, produces hydrogen peroxide (H(2)O(2)), which interferes with the growth of other bacteria. Streptococcus mutans, a cariogenic bacterium, can coexist with S. sanguinis in dental plaque, but to do so, it needs a means of detoxifying the H(2)O(2) produced by S. sanguinis. In this study, we investigated the association of three oxidative stress factors, Dpr, superoxide dismutase (SOD), and AhpCF, with the resistance of S. sanguinis to H(2)O(2). The knockout of dpr and sod significantly increased susceptibility to H(2)O(2), while the knockout of ahpCF had no apparent effect on susceptibility. In particular, dpr inactivation resulted in hypersensitivity to H(2)O(2). Next, we sought to identify the factor(s) involved in the regulation of these oxidative stress genes and found that PerR negatively regulated dpr expression. The knockout of perR caused increased dpr expression levels, resulting in low-level susceptibility to H(2)O(2) compared with the wild type. Furthermore, we evaluated the roles of perR, dpr, and sod when S. mutans was cocultured with S. sanguinis. Culturing of the dpr or sod mutant with S. sanguinis showed a significant decrease in the S. mutans population ratio compared with the wild type, while the perR mutant increased the ratio. Our results suggest that dpr and sod in S. mutans are involved in coexistence with S. sanguinis, and PerR is associated with resistance to H(2)O(2) in regulating the expression of Dpr. | 2013 | 23263955 |
| 446 | 15 | 0.9956 | Identification of Lactobacillus reuteri genes specifically induced in the mouse gastrointestinal tract. Lactobacilli are common inhabitants of the gastrointestinal tracts of mammals and have received considerable attention due to their putative health-promoting properties. Little is known about the traits that enhance the ability of these bacteria to inhabit the gastrointestinal tract. In this paper we describe the development and application of a strategy based on in vivo expression technology (IVET) that enables detection of Lactobacillus reuteri genes specifically induced in the murine gut. A plasmid-based system was constructed containing 'ermGT (which confers lincomycin resistance) as the primary reporter gene for selection of promoters active in the gastrointestinal tract of mice treated with lincomycin. A second reporter gene, 'bglM (beta-glucanase), allowed differentiation between constitutive and in vivo inducible promoters. The system was successfully tested in vitro and in vivo by using a constitutive promoter. Application of the IVET system with chromosomal DNA of L. reuteri 100-23 and reconstituted lactobacillus-free mice revealed three genes induced specifically during colonization. Two of the sequences showed homology to genes encoding xylose isomerase (xylA) and peptide methionine sulfoxide reductase (msrB), which are involved in nutrient acquisition and stress responses, respectively. The third locus showed homology to the gene encoding a protein whose function is not known. Our IVET system has the potential to identify genes of lactobacilli that have not previously been functionally characterized but which may be essential for growth of these bacteria in the gastrointestinal ecosystem. | 2003 | 12676681 |
| 7971 | 16 | 0.9956 | Abiotic mechanism changing tetracycline resistance in root mucus layer of floating plant: The role of antibiotic-exudate complexation. Antibiotic contamination and antibiotic resistance have caused growing concerns in different aquatic environments. This work investigated the complexation between tetracycline chloride (TCH) and the molecular weight (MW)-fractionated root exudates - the key abiotic mechanism impacting antibiotic fate and antibiotic resistance in rhizosphere. Results show that the affinity of TCH to the high MW exudates (≥10 kDa) facilitated the TCH deposition on roots and meanwhile reinforced the expression of certain tetracycline resistance genes (i.e. tetA) and the growth of tetracycline resistant bacteria. The interaction between TCH and the lower MW exudates (<10 kDa) completely inhibited the bacteria growth even below the minimum inhibitory concentration of TCH. In microcosms, the abiotic interaction between TCH and root exudates made effects along with biotic processes. Persistent TCH stimulation (≥50 µg/L, 7 d) induced the change of tet gene abundance and bacteria phyla composition though the mediation of root exudates made the rhizosphere less sensitive to the TCH stress. Summarily, the affinity of antibiotics to root exudates varied with MWs, which was closely related to (i) the antibiotic fate in the root mucus layer, (ii) the bacteria inhibition capacity of antibiotics, and (iii) the antibiotic resistance and bacterial community. | 2021 | 33813291 |
| 8621 | 17 | 0.9955 | Effects of symbiotic bacteria on chemical sensitivity of Daphnia magna. The crustacean zooplankton Daphnia magna has been widely used for chemical toxicity tests. Although abiotic factors have been well documented in ecotoxicological test protocols, biotic factors that may affect the sensitivity to chemical compounds remain limited. Recently, we identified symbiotic bacteria that are critical for the growth and reproduction of D. magna. The presence of symbiotic bacteria on Daphnia raised the question as to whether these bacteria have a positive or negative effect on toxicity tests. In order to evaluate the effects of symbiotic bacteria on toxicity tests, bacteria-free Daphnia were prepared, and their chemical sensitivities were compared with that of Daphnia with symbiotic bacteria based on an acute immobilization test. The Daphnia with symbiotic bacteria showed higher chemical resistance to nonylphenol, fenoxycarb, and pentachlorophenol than bacteria-free Daphnia. These results suggested potential roles of symbiotic bacteria in the chemical resistance of its host Daphnia. | 2017 | 28292585 |
| 719 | 18 | 0.9955 | Polyamines are critical for the induction of the glutamate decarboxylase-dependent acid resistance system in Escherichia coli. As part of our studies on the biological functions of polyamines, we have used a mutant of Escherichia coli that lacks all the genes for polyamine biosynthesis for a global transcriptional analysis on the effect of added polyamines. The most striking early response to the polyamine addition is the increased expression of the genes for the glutamate-dependent acid resistance system (GDAR) that is important for the survival of the bacteria when passing through the acid environment of the stomach. Not only were the two genes for glutamate decarboxylases (gadA and gadB) and the gene for glutamate-γ-aminobutyrate antiporter (gadC) induced by the polyamine addition, but the various genes involved in the regulation of this system were also induced. We confirmed the importance of polyamines for the induction of the GDAR system by direct measurement of glutamate decarboxylase activity and acid survival. The effect of deletions of the regulatory genes on the GDAR system and the effects of overproduction of two of these genes were also studied. Strikingly, overproduction of the alternative σ factor rpoS and of the regulatory gene gadE resulted in very high levels of glutamate decarboxylase and almost complete protection against acid stress even in the absence of any polyamines. Thus, these data show that a major function of polyamines in E. coli is protection against acid stress by increasing the synthesis of glutamate decarboxylase, presumably by increasing the levels of the rpoS and gadE regulators. | 2013 | 24097985 |
| 8779 | 19 | 0.9955 | The Knockout of Enterobactin-Related Gene in Pectobacterium atrosepticum Results in Reduced Stress Resistance and Virulence towards the Primed Plants. Siderophores produced by microorganisms to scavenge iron from the environment have been shown to contribute to virulence and/or stress resistance of some plant pathogenic bacteria. Phytopathogenic bacteria of Pectobacterium genus possess genes for the synthesis of siderophore enterobactin, which role in plant-pathogen interactions has not been elucidated. In the present study we characterized the phenotype of the mutant strain of Pba deficient for the enterobactin-biosynthetic gene entA. We showed that enterobactin may be considered as a conditionally beneficial virulence factor of Pba. The entA knockout did not reduce Pba virulence on non-primed plants; however, salicylic acid-primed plants were more resistant to ΔentA mutant than to the wild type Pba. The reduced virulence of ΔentA mutant towards the primed plants is likely explained by its compromised resistance to oxidative stress. | 2021 | 34502502 |