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Powers, Matthew J., Edgardo Sanabria-Valentín, Albert A. Bowers, and Elizabeth A. Shank. "Inhibition of Cell Differentiation in Bacillus subtilis by Pseudomonas protegens." Journal of Bacteriology 197, no. 13 (March 30, 2015): 2129–38. http://dx.doi.org/10.1128/jb.02535-14.
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ABSTRACTInterspecies interactions have been described for numerous bacterial systems, leading to the identification of chemical compounds that impact bacterial physiology and differentiation for processes such as biofilm formation. Here, we identified soil microbes that inhibit biofilm formation and sporulation in the common soil bacteriumBacillus subtilis. We did so by creating a reporter strain that fluoresces when the transcription of a biofilm-specific gene is repressed. Using this reporter in a coculture screen, we identifiedPseudomonas putidaandPseudomonas protegensas bacteria that secrete compounds that inhibit biofilm gene expression inB. subtilis. The active compound produced byP. protegenswas identified as the antibiotic and antifungal molecule 2,4-diacetylphloroglucinol (DAPG). Colonies ofB. subtilisgrown adjacent to a DAPG-producingP. protegensstrain had altered colony morphologies relative toB. subtiliscolonies grown next to a DAPG-nullP. protegensstrain (phlDstrain). Using a subinhibitory concentration of purified DAPG in a pellicle assay, we saw that biofilm-specific gene transcription was delayed relative to transcription in untreated samples. These transcriptional changes also corresponded to phenotypic alterations: both biofilm biomass and spore formation were reduced inB. subtilisliquid cultures treated with subinhibitory concentrations of DAPG. Our results add DAPG to the growing list of antibiotics that impact bacterial development and physiology at subinhibitory concentrations. These findings also demonstrate the utility of using coculture as a means to uncover chemically mediated interspecies interactions between bacteria.IMPORTANCEBiofilms are communities of bacteria adhered to surfaces by an extracellular matrix; such biofilms can have important effects in both clinical and agricultural settings. To identify chemical compounds that inhibited biofilm formation, we used a fluorescent reporter to screen for bacteria that inhibited biofilm gene expression inBacillus subtilis. We identifiedPseudomonas protegensas one such bacterium and found that the biofilm-inhibiting compound it produces was the antibiotic 2,4-diacetylphloroglucinol (DAPG). We showed that even at subinhibitory concentrations, DAPG inhibits biofilm formation and sporulation inB. subtilis. These findings have potential implications for understanding the interactions between these two microbes in the natural world and support the idea that many compounds considered antibiotics can impact bacterial development at subinhibitory concentrations.
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Jog, Rahul, Maharshi Pandya, G. Nareshkumar, and Shalini Rajkumar. "Mechanism of phosphate solubilization and antifungal activity of Streptomyces spp. isolated from wheat roots and rhizosphere and their application in improving plant growth." Microbiology 160, no. 4 (April 1, 2014): 778–88. http://dx.doi.org/10.1099/mic.0.074146-0.
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The application of plant-growth-promoting rhizobacteria (PGPR) at field scale has been hindered by an inadequate understanding of the mechanisms that enhance plant growth, rhizosphere incompetence and the inability of bacterial strains to thrive in different soil types and environmental conditions. Actinobacteria with their sporulation, nutrient cycling, root colonization, bio-control and other plant-growth-promoting activities could be potential field bio-inoculants. We report the isolation of five rhizospheric and two root endophytic actinobacteria from Triticum aestivum (wheat) plants. The cultures exhibited plant-growth-promoting activities, namely phosphate solubilization (1916 mg l−1), phytase (0.68 U ml−1), chitinase (6.2 U ml−1), indole-3-acetic acid (136.5 mg l−1) and siderophore (47.4 mg l−1) production, as well as utilizing all the rhizospheric sugars under test. Malate (50–55 mmol l−1) was estimated in the culture supernatant of the highest phosphate solublizer, Streptomyces mhcr0816. The mechanism of malate overproduction was studied by gene expression and assays of key glyoxalate cycle enzymes – isocitrate dehydrogenase (IDH), isocitrate lyase (ICL) and malate synthase (MS). The significant increase in gene expression (ICL fourfold, MS sixfold) and enzyme activity (ICL fourfold, MS tenfold) of ICL and MS during stationary phase resulted in malate production as indicated by lowered pH (2.9) and HPLC analysis (retention time 13.1 min). Similarly, the secondary metabolites for chitinase-independent biocontrol activity of Streptomyces mhcr0817, as identified by GC-MS and 1H-NMR spectra, were isoforms of pyrrole derivatives. The inoculation of actinobacterial isolate mhce0811 in T. aestivum (wheat) significantly improved plant growth, biomass (33 %) and mineral (Fe, Mn, P) content in non-axenic conditions. Thus the actinobacterial isolates reported here were efficient PGPR possessing significant antifungal activity and may have potential field applications.
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Traag, Bjorn A., Antonia Pugliese, Jonathan A. Eisen, and Richard Losick. "Gene Conservation among Endospore-Forming Bacteria Reveals Additional Sporulation Genes in Bacillus subtilis." Journal of Bacteriology 195, no. 2 (November 2, 2012): 253–60. http://dx.doi.org/10.1128/jb.01778-12.
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ABSTRACTThe capacity to form endospores is unique to certain members of the low-G+C group of Gram-positive bacteria (Firmicutes) and requires signature sporulation genes that are highly conserved across members of distantly related genera, such asClostridiumandBacillus. Using gene conservation among endospore-forming bacteria, we identified eight previously uncharacterized genes that are enriched among endospore-forming species. The expression of five of these genes was dependent on sporulation-specific transcription factors. Mutants of none of the genes exhibited a conspicuous defect in sporulation, but mutants of two,ylxYandylyA, were outcompeted by a wild-type strain under sporulation-inducing conditions, but not during growth. In contrast, aylmCmutant displayed a slight competitive advantage over the wild type specific to sporulation-inducing conditions. The phenotype of aylyAmutant was ascribed to a defect in spore germination efficiency. This work demonstrates the power of combining phylogenetic profiling with reverse genetics and gene-regulatory studies to identify unrecognized genes that contribute to a conserved developmental process.
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Khanna, Kanika, Javier Lopez-Garrido, and Kit Pogliano. "Shaping an Endospore: Architectural Transformations During Bacillus subtilis Sporulation." Annual Review of Microbiology 74, no. 1 (September 8, 2020): 361–86. http://dx.doi.org/10.1146/annurev-micro-022520-074650.
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Endospore formation in Bacillus subtilis provides an ideal model system for studying development in bacteria. Sporulation studies have contributed a wealth of information about the mechanisms of cell-specific gene expression, chromosome dynamics, protein localization, and membrane remodeling, while helping to dispel the early view that bacteria lack internal organization and interesting cell biological phenomena. In this review, we focus on the architectural transformations that lead to a profound reorganization of the cellular landscape during sporulation, from two cells that lie side by side to the endospore, the unique cell within a cell structure that is a hallmark of sporulation in B. subtilis and other spore-forming Firmicutes. We discuss new insights into the mechanisms that drive morphogenesis, with special emphasis on polar septation, chromosome translocation, and the phagocytosis-like process of engulfment, and also the key experimental advances that have proven valuable in revealing the inner workings of bacterial cells.
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Wang, Lei, Yanfei Yu, Xinyi He, Xiufen Zhou, Zixin Deng, Keith F. Chater, and Meifeng Tao. "Role of an FtsK-Like Protein in Genetic Stability in Streptomyces coelicolor A3(2)." Journal of Bacteriology 189, no. 6 (January 5, 2007): 2310–18. http://dx.doi.org/10.1128/jb.01660-06.
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ABSTRACT Streptomyces coelicolor A3(2) does not have a canonical cell division cycle during most of its complex life cycle, yet it contains a gene (ftsKSC ) encoding a protein similar to FtsK, which couples the completion of cell division and chromosome segregation in unicellular bacteria such as Escherichia coli. Here, we show that various constructed ftsKSC mutants all grew apparently normally and sporulated but upon restreaking gave rise to many aberrant colonies and to high frequencies of chloramphenicol-sensitive mutants, a phenotype previously associated with large terminal deletions from the linear chromosome. Indeed, most of the aberrant colonies had lost large fragments near one or both chromosomal termini, as if chromosome ends had failed to reach their prespore destination before the closure of sporulation septa. A constructed FtsKSC-enhanced green fluorescent protein fusion protein was particularly abundant in aerial hyphae, forming distinctive complexes before localizing to each sporulation septum, suggesting a role for FtsKSC in chromosome segregation during sporulation. Use of a fluorescent reporter showed that when ftsKSC was deleted, several spore compartments in most spore chains failed to express the late-sporulation-specific sigma factor gene sigF, even though they contained chromosomal DNA. This suggested that sigF expression is autonomously activated in each spore compartment in response to completion of chromosome transfer, which would be a previously unknown checkpoint for late-sporulation-specific gene expression. These results provide new insight into the genetic instability prevalent among streptomycetes, including those used in the industrial production of antibiotics.
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Hoover, Sharon E., Weihong Xu, Wenzhong Xiao, and William F. Burkholder. "Changes in DnaA-Dependent Gene Expression Contribute to the Transcriptional and Developmental Response of Bacillus subtilis to Manganese Limitation in Luria-Bertani Medium." Journal of Bacteriology 192, no. 15 (May 28, 2010): 3915–24. http://dx.doi.org/10.1128/jb.00210-10.
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ABSTRACT The SOS response to DNA damage in bacteria is a well-known component of the complex transcriptional responses to genotoxic environmental stresses such as exposure to reactive oxygen species, alkylating agents, and many of the antibiotics targeting DNA replication. However, bacteria such as Bacillus subtilis also respond to conditions that perturb DNA replication via a transcriptional response mediated by the replication initiation protein DnaA. In addition to regulating the initiation of DNA replication, DnaA directly regulates the transcription of specific genes. Conditions that perturb DNA replication can trigger the accumulation of active DnaA, activating or repressing the transcription of genes in the DnaA regulon. We report here that simply growing B. subtilis in LB medium altered DnaA-dependent gene expression in a manner consistent with the accumulation of active DnaA and that this was part of a general transcriptional response to manganese limitation. The SOS response to DNA damage was not induced under these conditions. One of the genes positively regulated by DnaA in Bacillus subtilis encodes a protein that inhibits the initiation of sporulation, Sda. Sda expression was induced as cells entered stationary phase in LB medium but not in LB medium supplemented with manganese, and the induction of Sda inhibited sporulation-specific gene expression and the onset of spore morphogenesis. In the absence of Sda, manganese-limited cells initiated spore development but failed to form mature spores. These data highlight that DnaA-dependent gene expression may influence the response of bacteria to a range of environmental conditions, including conditions that are not obviously associated with genotoxic stress.
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da Silva, Marliane de Cássia Soares, Igor Rodrigues Mendes, Thiago de Almeida Paula, Roberto Sousa Dias, Sérgio Oliveira de Paula, Cynthia Canedo Silva, Denise Mara Soares Bazzolli, and Maria Catarina Megumi Kasuya. "Expression of thenifHgene in diazotrophic bacteria inEucalyptus urograndisplantations." Canadian Journal of Forest Research 46, no. 2 (February 2016): 190–99. http://dx.doi.org/10.1139/cjfr-2015-0063.
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A large proportion of eucalypt plantations in Brazil are located in areas with low soil fertility. The actions of microorganisms are of great importance for the cycling of nutrients, including nitrogen (N), that are essential for plant metabolism. Denaturing gradient gel electrophoresis (DGGE) was used to monitor and identify the total and active microorganisms involved in the N cycle in both the soil and root systems of a forest of Eucalyptus urograndis with sections that were fertilized with N or unfertilized. Quantitative real-time PCR was used to examine the expression of the nifH gene in N-fixing bacteria present in both the soil and root systems. According to the DGGE analysis, in the total and active populations of N-fixing bacteria, the presence and expression of the nifH gene were influenced by the winter and summer seasons and (or) N fertilization, respectively. DGGE band sequencing from total DNA samples showed that the most abundant group of diazotrophic bacteria belonged to Alphaproteobacteria in both the soil and root systems. Quantitative real-time PCR revealed that nifH expression was higher in the soil samples, especially in those that did not receive N fertilization. The differences in the composition of the total and active diazotrophic populations highlight the importance of evaluating the active populations, because they are effectively responsible for the biogeochemical transformation of N and also control its’ availability to plants.
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Ramos-Silva, Paula, Mónica Serrano, and Adriano O. Henriques. "From Root to Tips: Sporulation Evolution and Specialization in Bacillus subtilis and the Intestinal Pathogen Clostridioides difficile." Molecular Biology and Evolution 36, no. 12 (July 29, 2019): 2714–36. http://dx.doi.org/10.1093/molbev/msz175.
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Abstract Bacteria of the Firmicutes phylum are able to enter a developmental pathway that culminates with the formation of highly resistant, dormant endospores. Endospores allow environmental persistence, dissemination and for pathogens, are also infection vehicles. In both the model Bacillus subtilis, an aerobic organism, and in the intestinal pathogen Clostridioides difficile, an obligate anaerobe, sporulation mobilizes hundreds of genes. Their expression is coordinated between the forespore and the mother cell, the two cells that participate in the process, and is kept in close register with the course of morphogenesis. The evolutionary mechanisms by which sporulation emerged and evolved in these two species, and more broadly across Firmicutes, remain largely unknown. Here, we trace the origin and evolution of sporulation using the genes known to be involved in the process in B. subtilis and C. difficile, and estimating their gain-loss dynamics in a comprehensive bacterial macroevolutionary framework. We show that sporulation evolution was driven by two major gene gain events, the first at the base of the Firmicutes and the second at the base of the B. subtilis group and within the Peptostreptococcaceae family, which includes C. difficile. We also show that early and late sporulation regulons have been coevolving and that sporulation genes entail greater innovation in B. subtilis with many Bacilli lineage-restricted genes. In contrast, C. difficile more often recruits new sporulation genes by horizontal gene transfer, which reflects both its highly mobile genome, the complexity of the gut microbiota, and an adjustment of sporulation to the gut ecosystem.
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Lin, Ta-Hui, Guei-Tsung Wei, Chien-Chen Su, and Gwo-Chyuan Shaw. "AdeR, a PucR-Type Transcription Factor, Activates Expression of l-Alanine Dehydrogenase and Is Required for Sporulation of Bacillus subtilis." Journal of Bacteriology 194, no. 18 (July 13, 2012): 4995–5001. http://dx.doi.org/10.1128/jb.00778-12.
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ABSTRACTTheBacillus subtilis aldgene encodesl-alanine dehydrogenase, which catalyzes the NAD+-dependent deamination ofl-alanine to pyruvate for the generation of energy and is required for normal sporulation. The transcription ofaldis induced by alanine, but the mechanism underlying alanine induction remains unknown. Here we report that a gene (formerlyyukFand now designatedadeR) located upstream ofaldis essential for the basal and alanine-inducible expression ofald. The disruption of theadeRgene caused a sporulation defect, whereas the complementation of anadeRmutation with an intactadeRgene restored the sporulation ability.adeRexpression was not subject to autoregulation and alanine induction. Deletion and mutation analyses revealed that an inverted repeat, centered at position −74.5 relative to the transcriptional initiation site ofald, was required foraldexpression and also likely served as a ρ-independent transcription terminator. Electrophoretic mobility shift assays showed that purified His-tagged AdeR was a specific DNA-binding protein and that this inverted repeat was required for AdeR binding. AdeR shows no significant amino acid sequence similarity to the known transcriptional activators ofaldgenes from other bacteria. AdeR appears to be a member of the PucR family of transcriptional regulators. Its orthologs of unknown function are present in some otherBacillusspecies. Collectively, these findings support the notion that AdeR is a transcriptional activator which mediatesaldexpression in response to alanine availability and is important for normal sporulation inB. subtilis.
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Garbeva, Paolina, and Wietse de Boer. "Inter-specific Interactions Between Carbon-limited Soil Bacteria Affect Behavior and Gene Expression." Microbial Ecology 58, no. 1 (March 7, 2009): 36–46. http://dx.doi.org/10.1007/s00248-009-9502-3.
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Bergman, Nicholas H., Erica C. Anderson, Ellen E. Swenson, Matthew M. Niemeyer, Amy D. Miyoshi, and Philip C. Hanna. "Transcriptional Profiling of the Bacillus anthracis Life Cycle In Vitro and an Implied Model for Regulation of Spore Formation." Journal of Bacteriology 188, no. 17 (September 1, 2006): 6092–100. http://dx.doi.org/10.1128/jb.00723-06.
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ABSTRACT The life cycle of Bacillus anthracis includes both vegetative and endospore morphologies which alternate based on nutrient availability, and there is considerable evidence indicating that the ability of this organism to cause anthrax depends on its ability to progress through this life cycle in a regulated manner. Here we report the use of a custom B. anthracis GeneChip in defining the gene expression patterns that occur throughout the entire life cycle in vitro. Nearly 5,000 genes were expressed in five distinct waves of transcription as the bacteria progressed from germination through sporulation, and we identified a specific set of functions represented within each wave. We also used these data to define the temporal expression of the spore proteome, and in doing so we have demonstrated that much of the spore's protein content is not synthesized de novo during sporulation but rather is packaged from preexisting stocks. We explored several potential mechanisms by which the cell could control which proteins are packaged into the developing spore, and our analyses were most consistent with a model in which B. anthracis regulates the composition of the spore proteome based on protein stability. This study is by far the most comprehensive survey yet of the B. anthracis life cycle and serves as a useful resource in defining the growth-phase-dependent expression patterns of each gene. Additionally, the data and accompanying bioinformatics analyses suggest a model for sporulation that has broad implications for B. anthracis biology and offer new possibilities for microbial forensics and detection.
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Hauser, Hansjörg, and Gerben J. Zylstra. "Mammals, plants, bacteria, and soil: common problems and solutions in gene expression and analysis." Current Opinion in Biotechnology 12, no. 5 (October 2001): 437–38. http://dx.doi.org/10.1016/s0958-1669(00)00241-x.
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Hasman, Henrik, Frank M. Aarestrup, Anders Dalsgaard, and Luca Guardabassi. "Heterologous expression of glycopeptide resistance vanHAX gene clusters from soil bacteria in Enterococcus faecalis." Journal of Antimicrobial Chemotherapy 57, no. 4 (February 13, 2006): 648–53. http://dx.doi.org/10.1093/jac/dkl033.
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Vierling, Silke, Tilmann Weber, Wolfgang Wohlleben, and Günther Muth. "Evidence that an Additional Mutation Is Required To Tolerate Insertional Inactivation of the Streptomyces lividans recA Gene." Journal of Bacteriology 183, no. 14 (July 15, 2001): 4374–81. http://dx.doi.org/10.1128/jb.183.14.4374-4381.2001.
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ABSTRACT In contrast to recA of other bacteria, therecA gene of Streptomyces lividans has been described as indispensable for viability (G. Muth, D. Frese, A. Kleber, and W. Wohlleben, Mol. Gen. Genet. 255:420–428, 1997.). Therefore, a closer analysis of this gene was performed to detect possible unique features distinguishing theStreptomyces RecA protein from the well-characterizedEscherichia coli RecA protein. The S. lividans recA gene restored UV resistance and recombination activity of anE. coli recA mutant. Also, transcriptional regulation was similar to that of E. coli recA. Gel retardation experiments showed that S. lividans recA is also under control of the Streptomyces SOS repressor LexA. TheS. lividans recA gene could be replaced only by simultaneously expressing a plasmid encoded recA copy. Surprisingly, the recA expression plasmid could subsequently be eliminated using an incompatible plasmid without the loss of viability. Besides being UV sensitive and recombination deficient, all the mutants were blocked in sporulation. Genetic complementation restored UV resistance and recombination activity but did not affect the sporulation defect. This indicated that all therecA mutants had suffered from an additional mutation, which might allow toleration of a recA deficiency.
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Bælum, Jacob, Mette H. Nicolaisen, William E. Holben, Bjarne W. Strobel, Jan Sørensen, and Carsten S. Jacobsen. "Direct analysis of tfdA gene expression by indigenous bacteria in phenoxy acid amended agricultural soil." ISME Journal 2, no. 6 (March 20, 2008): 677–87. http://dx.doi.org/10.1038/ismej.2008.21.
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Li, Jihong, Sameera Sayeed, and Bruce A. McClane. "Prevalence of Enterotoxigenic Clostridium perfringens Isolates in Pittsburgh (Pennsylvania) Area Soils and Home Kitchens." Applied and Environmental Microbiology 73, no. 22 (September 28, 2007): 7218–24. http://dx.doi.org/10.1128/aem.01075-07.
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ABSTRACT In the United States and Europe, food poisoning due to Clostridium perfringens type A is predominantly caused by C. perfringens isolates carrying a chromosomal enterotoxin gene (cpe). Neither the reservoir for these isolates nor the point in the food chain where these bacteria contaminate foods is currently understood. Therefore, the current study investigated whether type A isolates carrying a chromosomal cpe gene are present in two potential reservoirs, i.e., soil and home kitchen surfaces. No C. perfringens isolates were recovered from home kitchen surfaces, but most surveyed soil samples contained C. perfringens. The recovered soil isolates were predominantly type A, but some type C, D, and E soil isolates were also identified. All cpe-positive isolates recovered from soil were genotyped as type A, with their cpe genes on cpe plasmids rather than the chromosome. However, two cpe-positive soil isolates did not carry a classical cpe plasmid. Both of those atypical cpe-positive soil isolates were sporulation capable yet failed to produce C. perfringens enterotoxin, possibly because of differences in their upstream promoter regions. Collectively these results suggest that neither soil nor home kitchen surfaces represent major reservoirs for type A isolates with chromosomal cpe that cause food poisoning, although soil does appear to be a reservoir for cpe-positive isolates causing non-food-borne gastrointestinal diseases.
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Miller, Ashley K., and Brent L. Nielsen. "Analysis of Gene Expression Changes in Plants Grown in Salty Soil in Response to Inoculation with Halophilic Bacteria." International Journal of Molecular Sciences 22, no. 7 (March 31, 2021): 3611. http://dx.doi.org/10.3390/ijms22073611.
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Soil salinity is an increasing problem facing agriculture in many parts of the world. Climate change and irrigation practices have led to decreased yields of some farmland due to increased salt levels in the soil. Plants that have tolerance to salt are thus needed to feed the world’s population. One approach addressing this problem is genetic engineering to introduce genes encoding salinity, but this approach has limitations. Another fairly new approach is the isolation and development of salt-tolerant (halophilic) plant-associated bacteria. These bacteria are used as inoculants to stimulate plant growth. Several reports are now available, demonstrating how the use of halophilic inoculants enhance plant growth in salty soil. However, the mechanisms for this growth stimulation are as yet not clear. Enhanced growth in response to bacterial inoculation is expected to be associated with changes in plant gene expression. In this review, we discuss the current literature and approaches for analyzing altered plant gene expression in response to inoculation with halophilic bacteria. Additionally, challenges and limitations to current approaches are analyzed. A further understanding of the molecular mechanisms involved in enhanced plant growth when inoculated with salt-tolerant bacteria will significantly improve agriculture in areas affected by saline soils.
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Le Breton, Yoann, Nrusingh Prasad Mohapatra, and W. G. Haldenwang. "In Vivo Random Mutagenesis of Bacillus subtilis by Use of TnYLB-1, a mariner-Based Transposon." Applied and Environmental Microbiology 72, no. 1 (January 2006): 327–33. http://dx.doi.org/10.1128/aem.72.1.327-333.2006.
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ABSTRACT This report describes the construction and characterization of a mariner-based transposon system designed to be used in Bacillus subtilis, but potentially applicable to other gram-positive bacteria. Two pUC19-derived plasmids were created that contain the mariner-Himar1 transposase gene, modified for expression in B. subtilis, under the control of either σA- or σB-dependent promoters. Both plasmids also contain a transposable element (TnYLB-1) consisting of a Kanr cassette bracketed by the Himar1-recognized inverse terminal repeats, as well as the temperature-sensitive replicon and Ermr gene of pE194ts. TnYLB-1 transposes into the B. subtilis chromosome with high frequency (10−2) from either plasmid. Southern hybridization analyses of 15 transposants and sequence analyses of the insertion sites of 10 of these are consistent with random transposition, requiring only a “TA” dinucleotide as the essential target in the recipient DNA. Two hundred transposants screened for sporulation proficiency and auxotrophy yielded five Spo− clones, three with insertions in known sporulation genes (kinA, spoVT, and yqfD) and two in genes (ybaN and yubB) with unknown functions. Two auxotrophic mutants were identified among the 200 transposants, one with an insertion in lysA and another in a gene (yjzB) whose function is unknown.
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Jousset, Alexandre, Laurène Rochat, Arnaud Lanoue, Michael Bonkowski, Christoph Keel, and Stefan Scheu. "Plants Respond to Pathogen Infection by Enhancing the Antifungal Gene Expression of Root-Associated Bacteria." Molecular Plant-Microbe Interactions® 24, no. 3 (March 2011): 352–58. http://dx.doi.org/10.1094/mpmi-09-10-0208.
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Plant health and fitness widely depend on interactions with soil microorganisms. Some bacteria such as pseudomonads can inhibit pathogens by producing antibiotics, and controlling these bacteria could help improve plant fitness. In the present study, we tested whether plants induce changes in the antifungal activity of root-associated bacteria as a response to root pathogens. We grew barley plants in a split-root system with one side of the root system challenged by the pathogen Pythium ultimum and the other side inoculated with the biocontrol strain Pseudomonas fluorescens CHA0. We used reporter genes to follow the expression of ribosomal RNA indicative of the metabolic state and of the gene phlA, required for production of 2,4-diacetylphloroglucinol, a key component of antifungal activity. Infection increased the expression of the antifungal gene phlA. No contact with the pathogen was required, indicating that barley influenced gene expression by the bacteria in a systemic way. This effect relied on increased exudation of diffusible molecules increasing phlA expression, suggesting that communication with rhizosphere bacteria is part of the pathogen response of plants. Tripartite interactions among plants, pathogens, and bacteria appear as a novel determinant of plant response to root pathogens.
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Johnston, A., J. Todd, R. Rogers, N. Nikolaidou-Katsaridou, S. Li, and A. Curson. "Signalling of gene expression in rhizosphere bacteria — Iron in the soil and sulphur in the seas." Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology 146, no. 4 (April 2007): S217—S218. http://dx.doi.org/10.1016/j.cbpa.2007.01.474.
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Kois, Agnieszka, Magdalena Świątek, Dagmara Jakimowicz, and Jolanta Zakrzewska-Czerwińska. "SMC Protein-Dependent Chromosome Condensation during Aerial Hyphal Development in Streptomyces." Journal of Bacteriology 191, no. 1 (October 17, 2008): 310–19. http://dx.doi.org/10.1128/jb.00513-08.
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ABSTRACT Members of the SMC (structural maintenance of chromosomes) protein family play a central role in higher-order chromosome dynamics from bacteria to humans. So far, studies of bacterial SMC proteins have focused only on unicellular rod-shaped organisms that divide by binary fission. The conversion of multigenomic aerial hyphae of the mycelial organism Streptomyces coelicolor into chains of unigenomic spores requires the synchronous segregation of multiple chromosomes. Here we focus on the contribution of SMC proteins to sporulation-associated chromosome segregation in S. coelicolor. Deletion of the smc gene causes aberrant DNA condensation and missegregation of chromosomes (7.5% anucleate spores). In vegetative mycelium, immunostained SMC proteins were observed sporadically, while in aerial hyphae about to undergo sporulation they appeared as irregularly spaced foci which accompanied but did not colocalize with ParB complexes. Our data demonstrate that efficient chromosome segregation requires the joint action of SMC and ParB proteins. SMC proteins, similarly to ParAB and FtsZ, presumably belong to a larger group of proteins whose expression is highly induced in response to the requirement of aerial hyphal maturation.
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Fong, Karen P., Whasun O. Chung, Richard J. Lamont, and Donald R. Demuth. "Intra- and Interspecies Regulation of Gene Expression by Actinobacillus actinomycetemcomitansLuxS." Infection and Immunity 69, no. 12 (December 1, 2001): 7625–34. http://dx.doi.org/10.1128/iai.69.12.7625-7634.2001.
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ABSTRACT The cell density-dependent control of gene expression is employed by many bacteria for regulating a variety of physiological functions, including the generation of bioluminescence, sporulation, formation of biofilms, and the expression of virulence factors. Although periodontal organisms do not appear to secrete acyl-homoserine lactone signals, several species, e.g., Porphyromonas gingivalis,Prevotella intermedia, and Fusobacterium nucleatum, have recently been shown to secrete a signal related to the autoinducer II (AI-2) of the signal system 2 pathway inVibrio harveyi. Here, we report that the periodontal pathogen Actinobacillus actinomycetemcomitans expresses a homolog of V. harveyi luxS and secretes an AI-2-like signal. Cell-free conditioned medium from A. actinomycetemcomitans or from a recombinant Escherichia coli strain (E. coli AIS) expressing A. actinomycetemcomitans luxS induced luminescence in V. harveyi BB170 >200-fold over controls. AI-2 levels peaked in mid-exponential-phase cultures of A. actinomycetemcomitans and were significantly reduced in late-log- and stationary-phase cultures. Incubation of early-log-phaseA. actinomycetemcomitans cells with conditioned medium from A. actinomycetemcomitans or from E. coli AIS resulted in a threefold induction of leukotoxic activity and a concomitant increase in leukotoxin polypeptide. In contrast, no increase in leukotoxin expression occurred when cells were exposed to sterile medium or to conditioned broth from E. coli AIS−, a recombinant strain in whichluxS was insertionally inactivated. A. actinomycetemcomitans AI-2 also induced expression ofafuA, encoding a periplasmic iron transport protein, approximately eightfold, suggesting that LuxS-dependent signaling may play a role in the regulation of iron acquisition by A. actinomycetemcomitans. Finally, A. actinomycetemcomitans AI-2 added in transcomplemented a luxS knockout mutation in P. gingivalis by modulating the expression of theluxS-regulated genes uvrB andhasF in this organism. Together, these results suggest that LuxS-dependent signaling may modulate aspects of virulence and the uptake of iron by A. actinomycetemcomitans and induce responses in other periodontal organisms in mixed-species oral biofilm.
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Viswanathan, Poorna, Mitchell Singer, and Lee Kroos. "Role of σD in Regulating Genes and Signals during Myxococcus xanthus Development." Journal of Bacteriology 188, no. 9 (May 1, 2006): 3246–56. http://dx.doi.org/10.1128/jb.188.9.3246-3256.2006.
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ABSTRACT Starvation-induced development of Myxococcus xanthus is an excellent model for biofilm formation because it involves cell-cell signaling to coordinate formation of multicellular mounds, gene expression, and cellular differentiation into spores. The role of σD, an alternative σ factor important for viability in stationary phase and for stress responses, was investigated during development by measuring signal production, gene expression, and sporulation of a sigD null mutant alone and upon codevelopment with wild-type cells or signaling mutants. The sigD mutant responded to starvation by inducing (p)ppGpp synthesis normally but was impaired for production of A-signal, an early cell density signal, and for production of the morphogenetic C-signal. Induction of early developmental genes was greatly reduced, and expression of those that depend on A-signal was not restored by codevelopment with wild-type cells, indicating that σD is needed for cellular responses to A-signal. Despite these early developmental defects, the sigD mutant responded to C-signal supplied by codeveloping wild-type cells by inducing a subset of late developmental genes. σD RNA polymerase is dispensable for transcription of this subset, but a distinct regulatory class, which includes genes essential for sporulation, requires σD RNA polymerase or a gene under its control, cell autonomously. The level of sigD transcript in a relA mutant during growth is much lower than in wild-type cells, suggesting that (p)ppGpp positively regulates sigD transcription in growing cells. The sigD transcript level drops in wild-type cells after 20 min of starvation and remains low after 40 min but rises in a relA mutant after 40 min, suggesting that (p)ppGpp negatively regulates sigD transcription early in development. We conclude that σD synthesized during growth occupies a position near the top of a regulatory hierarchy governing M. xanthus development, analogous to σ factors that control biofilm formation of other bacteria.
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Chakraborty, Arindam, Atif Aziz Chowdhury, Kiron Bhakat, and Ekramul Islam. "Elevated level of arsenic negatively influences nifH gene expression of isolated soil bacteria in culture condition as well as soil system." Environmental Geochemistry and Health 41, no. 5 (February 14, 2019): 1953–66. http://dx.doi.org/10.1007/s10653-019-00261-2.
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DeCoste, Nadine J., Vijay J. Gadkar, and Martin Filion. "Verticillium dahliaealtersPseudomonasspp. populations and HCN gene expression in the rhizosphere of strawberry." Canadian Journal of Microbiology 56, no. 11 (November 2010): 906–15. http://dx.doi.org/10.1139/w10-080.
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The production of hydrogen cyanide (HCN) by beneficial root-associated bacteria is an important mechanism for the biological control of plant pathogens. However, little is known about the biotic factors affecting HCN gene expression in the rhizosphere of plants. In this study, real-time reverse transcription PCR (qRT–PCR) assays were developed to investigate the effect of the plant pathogen Verticillium dahliae on hcnC (encoding for HCN biosynthesis) gene expression in Pseudomonas sp. LBUM300. Strawberry plants were inoculated with Pseudomonas sp. LBUM300 and (or) V. dahliae and grown in pots filled with nonsterilized field soil. RNA was extracted from rhizosphere soil sampled at 0, 15, 30, and 45 days following inoculation with V. dahliae and used for qRT–PCR analyses. Populations of V. dahliae and Pseudomonas sp. LBUM300 were also monitored using a culture-independent qPCR approach. hcnC expression was detected at all sampling dates. The presence of V. dahliae had a significant stimulation effect on hcnC gene expression and also increased the population of Pseudomonas sp. LBUM300. However, the V. dahliae population was not altered by the presence of Pseudomonas sp. LBUM300. To our knowledge, this study is the first to evaluate the effect of a plant pathogen on HCN gene expression in the rhizosphere soil.
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Chung, Eu Jin, He Kyoung Lim, Jin-Cheol Kim, Gyung Ja Choi, Eun Jin Park, Myung Hwan Lee, Young Ryun Chung, and Seon-Woo Lee. "Forest Soil Metagenome Gene Cluster Involved in Antifungal Activity Expression in Escherichia coli." Applied and Environmental Microbiology 74, no. 3 (December 7, 2007): 723–30. http://dx.doi.org/10.1128/aem.01911-07.
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ABSTRACT Using two forest soils, we previously constructed two fosmid libraries containing 113,700 members in total. The libraries were screened to select active antifungal clones using Saccharomyces cerevisiae as a target fungus. One clone from the Yuseong pine tree rhizosphere soil library, pEAF66, showed S. cerevisiae growth inhibition. Despite an intensive effort, active chemicals were not isolated. DNA sequence analysis and transposon mutagenesis of pEAF66 revealed 39 open reading frames (ORFs) and indicated that eight ORFs, probably in one transcriptional unit, might be directly involved in the expression of antifungal activity in Escherichia coli. The deduced amino acid sequences of eight ORFs were similar to those of the core genes encoding type II family polyketide synthases, such as the acyl carrier protein (ACP), ACP synthases, aminotransferase, and ACP reductase. The gene cluster involved in antifungal activity was similar in organization to the putative antibiotic production locus of Pseudomonas putida KT2440, although we could not select a similar active clone from the KT2440 genomic DNA library in E. coli. ORFs encoding ATP binding cassette transporters and membrane proteins were located at both ends of the antifungal gene cluster. Upstream ORFs encoding an IclR family response regulator and a LysR family response regulator were involved in the positive regulation of antifungal gene expression. Our results suggested the metagenomic approach as an alternative to search for novel antifungal antibiotics from unculturable soil bacteria. This is the first report of an antifungal gene cluster obtained from a soil metagenome using S. cerevisiae as a target fungus.
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Yang, Zhaomin, Yongzhi Geng, and Wenyuan Shi. "A DnaK Homolog in Myxococcus xanthus Is Involved in Social Motility and Fruiting Body Formation." Journal of Bacteriology 180, no. 2 (January 15, 1998): 218–24. http://dx.doi.org/10.1128/jb.180.2.218-224.1998.
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ABSTRACT Myxococcus xanthus is a gram-negative soil bacterium which exhibits a complex life cycle and social behavior. In this study, two developmental mutants of M. xanthus were isolated through Tn5 transposon mutagenesis. The mutants were found to be defective in cellular aggregation as well as in sporulation. Further phenotypic characterization indicated that the mutants were defective in social motility but normal in directed cell movements. Both mutations were cloned by a transposon-tagging method. Sequence analysis indicated that both insertions occurred in the same gene, which encodes a homolog of DnaK. Unlike the dnaK genes in other bacteria, this M. xanthus homolog appears not to be regulated by temperature or heat shock and is constitutively expressed during vegetative growth and under starvation. The defects of the mutants indicate that this DnaK homolog is important for the social motility and development of M. xanthus.
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Taté, Rosarita, Michele Cermola, Anna Riccio, Maurizio Iaccarino, Mike Merrick, Reneé Favre, and Eduardo J. Patriarca. "Ectopic Expression of the Rhizobium etli amtB Gene Affects the Symbiosome Differentiation Process and Nodule Development." Molecular Plant-Microbe Interactions® 12, no. 6 (June 1999): 515–25. http://dx.doi.org/10.1094/mpmi.1999.12.6.515.
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Under conditions of nitrogen limitation, soil bacteria of the genus Rhizobium are able to induce the development of symbiotic nodules on the roots of leguminous plants. During nodule organogenesis, bacteria are released endocytotically inside the invaded plant cells where they differentiate into their endosymbiotic form called bacteroids. Bacteroids surrounded by a plant-derived peribacteroid membrane are nondividing, organelle-like structures, called symbiosomes, that use nitrogenase to reduce N2 to ammonia. Experiments performed in vitro with isolated symbiosomes have previously led to the suggestion that the NH3 produced by the bacteroids is released as NH4+ into the plant cytosol. Furthermore, it was observed that the bacterial amtB (ammonium/methylammonium transport B) gene is switched off very early during symbiosis, just when bacteria are released into the host cells. We report here that the ectopic expression of amtB in bacteroids alters the ability of bacteria to invade the host cells and the symbiosome differentiation process. Both the NtrC protein, which controls the expression of the bacterial genes involved in NH4+ assimilation, and the nitrogenase activity are essential to observe the amtB-mediated effect. Our results support the idea that in vivo bacteroids do not take up NH4+ and demonstrate that the transcriptional down-regulation of the amtB gene is essential for an effective symbiotic interaction.
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Capela, Delphine, Cédric Filipe, Christine Bobik, Jacques Batut, and Claude Bruand. "Sinorhizobium meliloti Differentiation During Symbiosis with Alfalfa: A Transcriptomic Dissection." Molecular Plant-Microbe Interactions® 19, no. 4 (April 2006): 363–72. http://dx.doi.org/10.1094/mpmi-19-0363.
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Sinorhizobium meliloti is a soil bacterium able to induce the formation of nodules on the root of specific legumes, including alfalfa (Medicago sativa). Bacteria colonize nodules through infection threads, invade the plant intracellularly, and ultimately differentiate into bacteroids capable of reducing atmospheric nitrogen to ammonia, which is directly assimilated by the plant. As a first step to describe global changes in gene expression of S. meliloti during the symbiotic process, we used whole genome microarrays to establish the transcriptome profile of bacteria from nodules induced by a bacterial mutant blocked at the infection stage and from wild-type nodules harvested at various timepoints after inoculation. Comparison of these profiles to those of cultured bacteria grown either to log or stationary phase as well as examination of a number of genes with known symbiotic transcription patterns allowed us to correlate global gene-expression patterns to three known steps of symbiotic bacteria bacteroid differentiation, i.e., invading bacteria inside infection threads, young differentiating bacteroids, and fully differentiated, nitrogen-fixing bacteroids. Finally, analysis of individual gene transcription profiles revealed a number of new potential symbiotic genes.
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Stretton, Serina, Somkiet Techkarnjanaruk, Alan M. McLennan, and Amanda E. Goodman. "Use of Green Fluorescent Protein To Tag and Investigate Gene Expression in Marine Bacteria." Applied and Environmental Microbiology 64, no. 7 (July 1, 1998): 2554–59. http://dx.doi.org/10.1128/aem.64.7.2554-2559.1998.
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ABSTRACT Two broad-host-range vectors previously constructed for use in soil bacteria (A. G. Matthysse, S. Stretton, C. Dandie, N. C. McClure, and A. E. Goodman, FEMS Microbiol. Lett. 145:87–94, 1996) were assessed by epifluorescence microscopy for use in tagging three marine bacterial species. Expression of gfp could be visualized in Vibrio sp. strain S141 cells at uniform levels of intensity from either the lac or thenpt-2 promoter, whereas expression of gfp could be visualized in Psychrobacter sp. strain SW5H cells at various levels of intensity only from the npt-2 promoter. Green fluorescent protein (GFP) fluorescence was not detected in the third species, Pseudoalteromonas sp. strain S91, when thegfp gene was expressed from either promoter. A new mini-Tn10-kan-gfp transposon was constructed to investigate further the possibilities of fluorescence tagging of marine bacteria. Insertion of mini-Tn10-kan-gfp generated random stable mutants at high frequencies with all three marine species. With this transposon, strongly and weakly expressed S91 promoters were isolated. Visualization of GFP by epifluorescence microscopy was markedly reduced when S91 (mini-Tn10-kan-gfp) cells were grown in rich medium compared to that when cells were grown in minimal medium. Mini-Tn10-kan-gfp was used to create an S91 chitinase-negative, GFP-positive mutant. Expression of the chi-gfp fusion was induced in cells exposed toN′-acetylglucosamine or attached to chitin particles. By laser scanning confocal microscopy, biofilms consisting of microcolonies of chi-negative, GFP+ S91 cells were found to be localized several microns from a natural chitin substratum. Tagging bacterial strains with GFP enables visualization of, as well as monitoring of gene expression in, living single cells in situ and in real time.
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Magdalena, Stella, Inez Johanna, and Yogiara Yogiara. "DETECTION OF QUORUM QUENCHING-PRODUCING BACTERIA FROM RHIZOSPHERE SOIL AS A BIOCONTROL AGENTS." TEKNOSAINS: MEDIA INFORMASI SAINS DAN TEKNOLOGI 15, no. 1 (January 5, 2021): 18. http://dx.doi.org/10.24252/teknosains.v15i1.16178.
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Quorum sensing is known as a communication mechanism among bacteria to control gene expression such as bioluminescence, pigmentation, and pathogenicity. Quorum quenching is known as inhibition of quorum sensing activity. In order to block quorum sensing activity, some bacteria produced enzymes which could degrade AHL, such as AHL-acylase, AHL-lactonase, and AHL-oxidase and reductase. In this study, soil bacteria were isolated and screened for their quorum quenching activity. These isolates were divided into Streptomyces and non-Streptomyces isolates. Detection were done by using Chromobacterium violaceum as an indicator bacteria for pigment inhibition by quorum quenching activity. About 10 out of 695 isolates were shown to possess quorum quenching activity. These isolates were further identified by biochemical tests, Gram staining, and identified by 16S rRNA sequencing. Four positive isolates showed similarity with Streptomyces sp., and 6 positive isolates were non-Streptomyces which showed similarity with Pseudomonas putida, Bacillus pumilus, Bacillus sp., Enterobacter ludwigii, and Enterobacter sp.
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Fenton, M., and B. D. W. Jarvis. "Expression of the symbiotic plasmid from Rhizobium leguminosarum biovar trifolii in Sphingobacterium multivorum." Canadian Journal of Microbiology 40, no. 10 (October 1, 1994): 873–79. http://dx.doi.org/10.1139/m94-138.
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An inoculant strain of Rhizobium leguminosarum biovar trifolii containing a Tn5 marked symbiotic plasmid transferred this plasmid by conjugation to Sphingobacterium multivorum, an organism that can be found in soil. The transconjugant bacteria nodulated the roots of white clover (Trifolium repens) seedlings but did not fix atmospheric nitrogen. Microscopic examination revealed abnormal nodule structures. Bacteria isolated from the nodules were shown to be closely related to the recipient S. multivorum and Southern blots of genomic digests probed with nodA DNA confirmed that the transconjugants contained symbiotic genes. This is the first report of the spontaneous transfer, by conjugation, of a symbiotic plasmid from R. leguminosarum biovar trifolii to S. multivorum.Key words: Rhizobium, Sphingobacterium, nodulation, nod gene transfer.
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İrigül-Sönmez, Öykü, Türkan E. Köroğlu, Büşra Öztürk, Ákos T. Kovács, Oscar P. Kuipers, and Ayten Yazgan-Karataş. "In Bacillus subtilis LutR is part of the global complex regulatory network governing the adaptation to the transition from exponential growth to stationary phase." Microbiology 160, no. 2 (February 1, 2014): 243–60. http://dx.doi.org/10.1099/mic.0.064675-0.
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The lutR gene, encoding a product resembling a GntR-family transcriptional regulator, has previously been identified as a gene required for the production of the dipeptide antibiotic bacilysin in Bacillus subtilis. To understand the broader regulatory roles of LutR in B. subtilis, we studied the genome-wide effects of a lutR null mutation by combining transcriptional profiling studies using DNA microarrays, reverse transcription quantitative PCR, lacZ fusion analyses and gel mobility shift assays. We report that 65 transcriptional units corresponding to 23 mono-cistronic units and 42 operons show altered expression levels in lutR mutant cells, as compared with lutR + wild-type cells in early stationary phase. Among these, 11 single genes and 25 operons are likely to be under direct control of LutR. The products of these genes are involved in a variety of physiological processes associated with the onset of stationary phase in B. subtilis, including degradative enzyme production, antibiotic production and resistance, carbohydrate utilization and transport, nitrogen metabolism, phosphate uptake, fatty acid and phospholipid biosynthesis, protein synthesis and translocation, cell-wall metabolism, energy production, transfer of mobile genetic elements, induction of phage-related genes, sporulation, delay of sporulation and cannibalism, and biofilm formation. Furthermore, an electrophoretic mobility shift assay performed in the presence of both SinR and LutR revealed a close overlap between the LutR and SinR targets. Our data also revealed a significant overlap with the AbrB regulon. Together, these findings reveal that LutR is part of the global complex, interconnected regulatory systems governing adaptation of bacteria to the transition from exponential growth to stationary phase.
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Husen, Edi. "THE USE OF gusA REPORTER GENE TO MONITOR THE SURVIVAL OF INTRODUCED BACTERIA IN THE SOIL." Indonesian Journal of Agricultural Science 6, no. 1 (July 23, 2013): 32. http://dx.doi.org/10.21082/ijas.v6n1.2005.32-38.
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An effective marker to monitor the survival of introduced bacteria in the soil is required for further evaluation of their beneficial effects on plant growth. This study tested the use of gusA gene as a marker to trace the fate of three Gram negative bacteria in the root, rhizosphere, and soil. The study was conducted at the laboratory and greenhouse of the National Institute of Molecular Biology and Biotechnology, Philippines from January to December 2001. Isolates TCaR 61 and TCeRe 60, and Azotobacter vinelandii Mac 259 were selected as test bacteria based on their ability to produce indole-3acetic acid and solubilize precipitated phosphate, which may promote plant growth in the field. These bacteria were marked with gusA reporter gene from Escherichia coli strain S17-1(λ-pir) containing mTn5SSgusA21. The gusA (β-glucuronidase) gene from the donor (E. coli) was transferred to each bacterium (recipient) through bacterial conjugation in mating procedures using tryptone-yeast agar followed by the selection of the transconjugants (bacteria receiving gusA) in tryptone-yeast agar supplemented with double antibiotics and X-GlcA (5bromo-4chloro- 3indoxyl-β-D-glucuronic acid). The antibiotics used were rifampicin and either streptomycin or spectinomycin based on antibiotic profiles of the donor and recipients. The results showed that the insertion of gusA gene into bacterial genomes of the recipient did not impair its phenotypic traits; the growth rates of the transconjugants as well as their ability to produce indole-3acetic acid and solubilize precipitated phosphate in pure culture were similar to their wild types. All transconjugants colonized the roots of hot pepper (Capsicum annuum L.) and survived in the rhizosphere and soil until the late of vegetative growth stage. The distinct blue staining of transconjugants as the expression of gusA gene in media containing X-GlcA coupled with their resistance to rifampicin and streptomycin or spectinomycin made them easier to be recognized and evaluated.<br /><br />
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Husen, Edi. "THE USE OF gusA REPORTER GENE TO MONITOR THE SURVIVAL OF INTRODUCED BACTERIA IN THE SOIL." Indonesian Journal of Agricultural Science 6, no. 1 (July 23, 2013): 32. http://dx.doi.org/10.21082/ijas.v6n1.2005.p32-38.
Full textAbstract:
An effective marker to monitor the survival of introduced bacteria in the soil is required for further evaluation of their beneficial effects on plant growth. This study tested the use of gusA gene as a marker to trace the fate of three Gram negative bacteria in the root, rhizosphere, and soil. The study was conducted at the laboratory and greenhouse of the National Institute of Molecular Biology and Biotechnology, Philippines from January to December 2001. Isolates TCaR 61 and TCeRe 60, and Azotobacter vinelandii Mac 259 were selected as test bacteria based on their ability to produce indole-3acetic acid and solubilize precipitated phosphate, which may promote plant growth in the field. These bacteria were marked with gusA reporter gene from Escherichia coli strain S17-1(λ-pir) containing mTn5SSgusA21. The gusA (β-glucuronidase) gene from the donor (E. coli) was transferred to each bacterium (recipient) through bacterial conjugation in mating procedures using tryptone-yeast agar followed by the selection of the transconjugants (bacteria receiving gusA) in tryptone-yeast agar supplemented with double antibiotics and X-GlcA (5bromo-4chloro- 3indoxyl-β-D-glucuronic acid). The antibiotics used were rifampicin and either streptomycin or spectinomycin based on antibiotic profiles of the donor and recipients. The results showed that the insertion of gusA gene into bacterial genomes of the recipient did not impair its phenotypic traits; the growth rates of the transconjugants as well as their ability to produce indole-3acetic acid and solubilize precipitated phosphate in pure culture were similar to their wild types. All transconjugants colonized the roots of hot pepper (Capsicum annuum L.) and survived in the rhizosphere and soil until the late of vegetative growth stage. The distinct blue staining of transconjugants as the expression of gusA gene in media containing X-GlcA coupled with their resistance to rifampicin and streptomycin or spectinomycin made them easier to be recognized and evaluated.<br /><br />
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Rodrigues, Christopher D. A., Xavier Henry, Emmanuelle Neumann, Vilius Kurauskas, Laure Bellard, Yann Fichou, Paul Schanda, Guy Schoehn, David Z. Rudner, and Cecile Morlot. "A ring-shaped conduit connects the mother cell and forespore during sporulation in Bacillus subtilis." Proceedings of the National Academy of Sciences 113, no. 41 (September 28, 2016): 11585–90. http://dx.doi.org/10.1073/pnas.1609604113.
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During spore formation in Bacillus subtilis a transenvelope complex is assembled across the double membrane that separates the mother cell and forespore. This complex (called the “A–Q complex”) is required to maintain forespore development and is composed of proteins with remote homology to components of type II, III, and IV secretion systems found in Gram-negative bacteria. Here, we show that one of these proteins, SpoIIIAG, which has remote homology to ring-forming proteins found in type III secretion systems, assembles into an oligomeric ring in the periplasmic-like space between the two membranes. Three-dimensional reconstruction of images generated by cryo-electron microscopy indicates that the SpoIIIAG ring has a cup-and-saucer architecture with a 6-nm central pore. Structural modeling of SpoIIIAG generated a 24-member ring with dimensions similar to those of the EM-derived saucer. Point mutations in the predicted oligomeric interface disrupted ring formation in vitro and impaired forespore gene expression and efficient spore formation in vivo. Taken together, our data provide strong support for the model in which the A–Q transenvelope complex contains a conduit that connects the mother cell and forespore. We propose that a set of stacked rings spans the intermembrane space, as has been found for type III secretion systems.
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Rutkevich, Daria A., Katsiaryna S. Karaleva, and Elena A. Khramtsova. "The influence of bacteria acdS-gene of Pseudomonas putida B-37 on Nicotiana tabacum transgenic plants under abiotic stress conditions." Journal of the Belarusian State University. Biology, no. 1 (March 6, 2020): 39–46. http://dx.doi.org/10.33581/2521-1722-2020-1-39-46.
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In the present work was carried out selection of transgenic plants of Nicotiana tabacum carrying acdS-gene of bacteria Pseudomonas putida B-37. Using polymerase chain reaction with specific primers, the presence of the target gene was proved. Transgenic plants selected on a selective medium were planted in the ground and subjected to abiotic stress caused by soil contamination with heavy metal salts (15 mg / kg for Cu2+ and 30 mg / kg for Cr6+ and Pb2+ ) and salinization of the soil (200 mmol/L NaCl). Reverse transcription polymerase chain reaction and real-time polymerase chain reaction were conducted and confirmed the transcriptional activity of the bacterial acdS-gene in transgenic plant cells at a level with the reference gene Ef-1a. Determination of activity of ACC-deaminase, the product of expression of the acdS-gene, confirmed the formation of the active enzyme in the leaf tissues of transgenic tobacco plants. The beneficial effect of the acdS-gene of the bacteria P. putida B-37 on transgenic N. tabacum plants under abiotic stress has been proven.
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Gehring, Amy M., Stephanie T. Wang, Daniel B. Kearns, Narie Yoo Storer, and Richard Losick. "Novel Genes That Influence Development in Streptomyces coelicolor." Journal of Bacteriology 186, no. 11 (June 1, 2004): 3570–77. http://dx.doi.org/10.1128/jb.186.11.3570-3577.2004.
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ABSTRACT Filamentous soil bacteria of the genus Streptomyces carry out complex developmental cycles that result in sporulation and production of numerous secondary metabolites with pharmaceutically important activities. To further characterize the molecular basis of these developmental events, we screened for mutants of Streptomyces coelicolor that exhibit aberrant morphological differentiation and/or secondary metabolite production. On the basis of this screening analysis and the subsequent complementation analysis of the mutants obtained we assigned developmental roles to a gene involved in methionine biosynthesis (metH) and two previously uncharacterized genes (SCO6938 and SCO2525) and we reidentified two previously described developmental genes (bldA and bldM). In contrast to most previously studied genes involved in development, the genes newly identified in the present study all appear to encode biosynthetic enzymes instead of regulatory proteins. The MetH methionine synthase appears to be required for conversion of aerial hyphae into chains of spores, SCO6938 is a probable acyl coenzyme A dehydrogenase that contributes to the proper timing of aerial mycelium formation and antibiotic production, and SCO2525 is a putative methyltransferase that influences various aspects of colony growth and development.
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Hu, Yan, Melanie M. Miller, Alan I. Derman, Brian L. Ellis, Rose Gomes Monnerat, Joe Pogliano, and Raffi V. Aroian. "Bacillus subtilis Strain Engineered for Treatment of Soil-Transmitted Helminth Diseases." Applied and Environmental Microbiology 79, no. 18 (July 8, 2013): 5527–32. http://dx.doi.org/10.1128/aem.01854-13.
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ABSTRACTSoil-transmitted helminths (hookworms, whipworms, and large roundworms) are agents of intestinal roundworm diseases of poverty that infect upwards of 2 billion people worldwide. A great challenge in treating these diseases is the development of anthelmintic therapeutics that are inexpensive, can be produced in great quantity, and are capable of delivery under varied and adverse environmental conditions. A potential solution to this challenge is the use of live bacteria that are acceptable for human consumption, e.g.,Bacillus subtilis, and that can be engineered with therapeutic properties. In this study, we expressed theBacillus thuringiensisanthelmintic protein Cry5B in a bacterial strain that has been used as a model for live bacterial therapy,Bacillus subtilisPY79. PY79 transformed with a Cry5B expression plasmid (PY79-Cry5B) is able to express Cry5B from the endogenousB. thuringiensis cry5Bpromoter. During sporulation of PY79-Cry5B, Cry5B is packaged as a crystal. Furthermore, Cry5B produced in PY79 is bioactive, with a 50% lethal concentration (LC50) of 4.3 μg/ml against the roundwormCaenorhabditis elegans. PY79-Cry5B was a significantly effective therapeutic in experimentalAncylostoma ceylanicumhookworm infections of hamsters. A single 10-mg/kg (0.071 μmol/kg of body weight) dose of Cry5B administered as a Cry5B-PY79 spore crystal lysate achieved a 93% reduction in hookworm burdens, which is superior on a molar level to reductions seen with clinically used anthelmintics. Given that a bacterial strain such as this one can be produced cheaply in massive quantities, our results demonstrate that the engineering and delivery of live bacterial strains have great potential to treat a significant contributor to poverty worldwide, namely, hookworm disease and other soil-transmitted helminthiasis.
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Chavira, Marielena, Nga Cao, Karen Le, Tanveer Riar, Navid Moradshahi, Melinda McBride, Renate Lux, and Wenyuan Shi. "β-d-Allose Inhibits Fruiting Body Formation and Sporulation in Myxococcus xanthus." Journal of Bacteriology 189, no. 1 (October 20, 2006): 169–78. http://dx.doi.org/10.1128/jb.00792-06.
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ABSTRACT Myxococcus xanthus, a gram-negative soil bacterium, responds to amino acid starvation by entering a process of multicellular development which culminates in the assembly of spore-filled fruiting bodies. Previous studies utilizing developmental inhibitors (such as methionine, lysine, or threonine) have revealed important clues about the mechanisms involved in fruiting body formation. We used Biolog phenotype microarrays to screen 384 chemicals for complete inhibition of fruiting body development in M. xanthus. Here, we report the identification of a novel inhibitor of fruiting body formation and sporulation, β-d-allose. β-d-Allose, a rare sugar, is a member of the aldohexose family and a C3 epimer of glucose. Our studies show that β-d-allose does not affect cell growth, viability, agglutination, or motility. However, β-galactosidase reporters demonstrate that genes activated between 4 and 14 h of development show significantly lower expression levels in the presence of β-d-allose. Furthermore, inhibition of fruiting body formation occurs only when β-d-allose is added to submerged cultures before 12 h of development. In competition studies, high concentrations of galactose and xylose antagonize the nonfruiting response to β-d-allose, while glucose is capable of partial antagonism. Finally, a magellan-4 transposon mutagenesis screen identified glcK, a putative glucokinase gene, required for β-d-allose-mediated inhibition of fruiting body formation. Subsequent glucokinase activity assays of the glcK mutant further supported the role of this protein in glucose phosphorylation.
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Egener, Tanja, Thomas Hurek, and Barbara Reinhold-Hurek. "Use of Green Fluorescent Protein to Detect Expression of nif Genes of Azoarcus sp. BH72, a Grass-Associated Diazotroph, on Rice Roots." Molecular Plant-Microbe Interactions® 11, no. 1 (January 1998): 71–75. http://dx.doi.org/10.1094/mpmi.1998.11.1.71.
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A gfp (green fluorescent protein) cassette for transcriptional fusions has been developed to study gene expression in Azoarcus sp. BH72 in association with plant roots. The bacteria expressed nitrogenase genes (nifHDK) in the rhi-zosphere, on root tips, and in epidermal cells of rice seedlings. Green fluorescent protein fusions also visualized promoter activity of single cells in soil.
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Arvizu Hernández, Iván, José Luis Hernández Flores, Juan Caballero Pérez, Héctor Gutiérrez Sánchez, Miguel Ángel Ramos López, Sergio Romero Gómez, Andrés Cruz Hernández, et al. "Analysis of tRNACys processing under salt stress in Bacillus subtilis spore outgrowth using RNA sequencing data." F1000Research 9 (June 3, 2020): 501. http://dx.doi.org/10.12688/f1000research.23780.1.
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Background: In spore-forming bacteria, the molecular mechanisms of accumulation of transfer RNA (tRNA) during sporulation must be a priority as tRNAs play an essential role in protein synthesis during spore germination and outgrowth. However, tRNA processing has not been extensively studied in these conditions, and knowledge of these mechanisms is important to understand long-term stress survival. Methods:To gain further insight into tRNA processing during spore germination and outgrowth, the expression of the single copy tRNACys gene was analyzed in the presence and absence of 1.2 M NaCl in Bacillus subtilis using RNA-Seq data obtained from the Gene Expression Omnibus (GEO) database. The CLC Genomics work bench 12.0.2 (CLC Bio, Aarhus, Denmark, https://www.qiagenbioinformatics.com/) was used to analyze reads from the tRNACys gene. Results:The results show that spores store different populations of tRNACys-related molecules. One such population, representing 60% of total tRNACys, was composed of tRNACys fragments. Half of these fragments (3´-tRF) possessed CC, CCA or incorrect additions at the 3´end. tRNACys with correct CCA addition at the 3´end represented 23% of total tRNACys, while with CC addition represented 9% of the total and with incorrect addition represented 7%. While an accumulation of tRNACys precursors was induced by upregulation of the rrnD operon under the control of σA -dependent promoters under both conditions investigated, salt stress produced only a modest effect on tRNACys expression and the accumulation of tRNACys related species. Conclusions:The results demonstrate that tRNACys molecules resident in spores undergo dynamic processing to produce functional molecules that may play an essential role during protein synthesis.
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Parente, Ana Flávia, Ildinete Silva-Pereira, José Ivo Baldani, Victor Hugo da Silva Tibúrcio, Sônia Nair Báo, and Marlene T. De-Souza. "Construction ofBacillus thuringiensiswild-type S76 and Cry–derivatives expressing a green fluorescent protein: two potential marker organisms to study bacteria–plant interactions." Canadian Journal of Microbiology 54, no. 9 (September 2008): 786–90. http://dx.doi.org/10.1139/w08-061.
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Collectively, the species Bacillus thuringiensis , Bacillus cereus , and Bacillus anthracis represent microorganisms of high economic, medical, and biodefense importance. Although the genetic correlation and pathogenic characteristics have been extensively dissected, the ecological properties of these three species in their natural environments remain poorly understood. Thus, a tractable marker for detecting these bacteria under specific environmental and physiological conditions is a valuable tool. With this purpose, a plasmid (pAD43-25) carrying a functional gfp gene sequence (gfpmut3A) was introduced into the wild-type strain Bacillus thuringiensis subsp. kurstaki S76, which bears approximately 11 plasmids, allowing constitutive synthesis of green fluorescent protein (GFP) during vegetative growth (strain S76GFP+). Additionally, this vector was transferred to a plasmid-cured (Cry–) B. thuringiensis host. Bright green cells were detected by fluorescence microscopy in both recombinants by 2 h after inoculation in liquid medium and could be seen throughout the remaining cultivation time until complete sporulation was accomplished. For strain S76GFP+protein profile and plasmid DNA analyses indicate, respectively, that this recombinant maintained Cry proteins expression and resident plasmid outline. Thus, in addition to the potential of strain S76GFP+as a marker organism in bacteria–plant interaction studies, the production and stability of active GFPmut3a make this unique expression system a useful experimental model to study adaptive changes of host–plasmid as well as plasmid–plasmid relationships in a population of cells stressed by the production of a recombinant protein.
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Medrano Romero, Veronica, and Kazuya Morikawa. "Listeria monocytogenes σHContributes to Expression of Competence Genes and Intracellular Growth." Journal of Bacteriology 198, no. 8 (February 1, 2016): 1207–17. http://dx.doi.org/10.1128/jb.00718-15.
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ABSTRACTThe alternative sigma factor σHhas two functions in Gram-positive bacteria: it regulates sporulation and the development of genetic competence.Listeria monocytogenesis a nonsporulating species in which competence has not yet been detected. Nevertheless, the main competence regulators and a series of orthologous genes that form the competence machinery are present in its genome; some of the competence genes play a role in optimal phagosomal escape. In this study, strains overexpressing σHand strains with a σHdeletion were used to elucidate the contribution of σHto the expression of the competence machinery genes inL. monocytogenes. Gene expression analysis showed that σHis, indeed, involved incomGandcomEregulation. Unexpectedly, we observed a unique regulation scheme in which σHand the transcription factor ComK were involved. Population-level analysis showed that even with the overexpression of both factors, only a fraction of the cells expressed the competence machinery genes. Although we could not detect competence, σHwas crucial for phagosomal escape, which implies that this alternative sigma factor has specifically evolved to regulate theL. monocytogenesintracellular life cycle.IMPORTANCEListeria monocytogenescan be an intracellular pathogen capable of causing serious infections in humans and animal species. Recently, the competence machinery genes were described as being necessary for optimal phagosomal escape, in which the transcription factor ComK plays an important role. On the other hand, our previous phylogenetic analysis suggested that the alternative sigma factor σHmight play a role in the regulation of competence genes. The present study shows that some of the competence genes belong to the σHregulon and, importantly, that σHis essential for intracellular growth, implying a unique physiological role of σHamongFirmicutes.
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Gudeta, Dereje Dadi, Valeria Bortolaia, Greg Amos, Elizabeth M. H. Wellington, Kristian K. Brandt, Laurent Poirel, Jesper Boye Nielsen, Henrik Westh, and Luca Guardabassi. "The Soil Microbiota Harbors a Diversity of Carbapenem-Hydrolyzing β-Lactamases of Potential Clinical Relevance." Antimicrobial Agents and Chemotherapy 60, no. 1 (October 19, 2015): 151–60. http://dx.doi.org/10.1128/aac.01424-15.
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ABSTRACTThe origin of carbapenem-hydrolyzing metallo-β-lactamases (MBLs) acquired by clinical bacteria is largely unknown. We investigated the frequency, host range, diversity, and functionality of MBLs in the soil microbiota. Twenty-five soil samples of different types and geographical origins were analyzed by antimicrobial selective culture, followed by phenotypic testing and expression of MBL-encoding genes inEscherichia coli, and whole-genome sequencing of MBL-producing strains was performed. Carbapenemase activity was detected in 29 bacterial isolates from 13 soil samples, leading to identification of seven new MBLs in presumptivePedobacter roseus(PEDO-1),Pedobacter borealis(PEDO-2),Pedobacter kyungheensis(PEDO-3),Chryseobacterium piscium(CPS-1),Epilithonimonas tenax(ESP-1),Massilia oculi(MSI-1), andSphingomonassp. (SPG-1). Carbapenemase production was likely an intrinsic feature inChryseobacteriumandEpilithonimonas, as it occurred in reference strains of different species within these genera. The amino acid identity to MBLs described in clinical bacteria ranged between 40 and 69%. Remarkable features of the new MBLs included prophage integration of the encoding gene (PEDO-1), an unusual amino acid residue at a key position for MBL structure and catalysis (CPS-1), and overlap with a putative OXA β-lactamase (MSI-1). Heterologous expression of PEDO-1, CPS-1, and ESP-1inE. colisignificantly increased the MICs of ampicillin, ceftazidime, cefpodoxime, cefoxitin, and meropenem. Our study shows that MBL producers are widespread in soil and include four genera that were previously not known to produce MBLs. The MBLs produced by these bacteria are distantly related to MBLs identified in clinical samples but constitute resistance determinants of clinical relevance if acquired by pathogenic bacteria.
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Romanowicz, Karl J., Byron C. Crump, and George W. Kling. "Rainfall Alters Permafrost Soil Redox Conditions, but Meta-Omics Show Divergent Microbial Community Responses by Tundra Type in the Arctic." Soil Systems 5, no. 1 (March 12, 2021): 17. http://dx.doi.org/10.3390/soilsystems5010017.
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Soil anoxia is common in the annually thawed surface (‘active’) layer of permafrost soils, particularly when soils are saturated, and supports anaerobic microbial metabolism and methane (CH4) production. Rainfall contributes to soil saturation, but can also introduce oxygen, causing soil oxidation and altering anoxic conditions. We simulated a rainfall event in soil mesocosms from two dominant tundra types, tussock tundra and wet sedge tundra, to test the impacts of rainfall-induced soil oxidation on microbial communities and their metabolic capacity for anaerobic CH4 production and aerobic respiration following soil oxidation. In both types, rainfall increased total soil O2 concentration, but in tussock tundra there was a 2.5-fold greater increase in soil O2 compared to wet sedge tundra due to differences in soil drainage. Metagenomic and metatranscriptomic analyses found divergent microbial responses to rainfall between tundra types. Active microbial taxa in the tussock tundra community, including bacteria and fungi, responded to rainfall with a decline in gene expression for anaerobic metabolism and a concurrent increase in gene expression for cellular growth. In contrast, the wet sedge tundra community showed no significant changes in microbial gene expression from anaerobic metabolism, fermentation, or methanogenesis following rainfall, despite an initial increase in soil O2 concentration. These results suggest that rainfall induces soil oxidation and enhances aerobic microbial respiration in tussock tundra communities but may not accumulate or remain in wet sedge tundra soils long enough to induce a community-wide shift from anaerobic metabolism. Thus, rainfall may serve only to maintain saturated soil conditions that promote CH4 production in low-lying wet sedge tundra soils across the Arctic.
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Mars, Ruben A. T., Pierre Nicolas, Emma L. Denham, and Jan Maarten van Dijl. "Regulatory RNAs in Bacillus subtilis: a Gram-Positive Perspective on Bacterial RNA-Mediated Regulation of Gene Expression." Microbiology and Molecular Biology Reviews 80, no. 4 (October 26, 2016): 1029–57. http://dx.doi.org/10.1128/mmbr.00026-16.
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SUMMARYBacteria can employ widely diverse RNA molecules to regulate their gene expression. Such molecules includetrans-acting small regulatory RNAs, antisense RNAs, and a variety of transcriptional attenuation mechanisms in the 5′ untranslated region. Thus far, most regulatory RNA research has focused on Gram-negative bacteria, such asEscherichia coliandSalmonella. Hence, there is uncertainty about whether the resulting insights can be extrapolated directly to other bacteria, such as the Gram-positive soil bacteriumBacillus subtilis. A recent study identified 1,583 putative regulatory RNAs inB. subtilis, whose expression was assessed across 104 conditions. Here, we review the current understanding of RNA-based regulation inB. subtilis, and we categorize the newly identified putative regulatory RNAs on the basis of their conservation in other bacilli and the stability of their predicted secondary structures. Our present evaluation of the publicly available data indicates that RNA-mediated gene regulation inB. subtilismostly involves elements at the 5′ ends of mRNA molecules. These can include 5′ secondary structure elements and metabolite-, tRNA-, or protein-binding sites. Importantly, sense-independent segments are identified as the most conserved and structured potential regulatory RNAs inB. subtilis. Altogether, the present survey provides many leads for the identification of new regulatory RNA functions inB. subtilis.
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Ramos-González, María Isabel, and Søren Molin. "Cloning, Sequencing, and Phenotypic Characterization of the rpoS Gene from Pseudomonas putida KT2440." Journal of Bacteriology 180, no. 13 (July 1, 1998): 3421–31. http://dx.doi.org/10.1128/jb.180.13.3421-3431.1998.
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ABSTRACT A gene homologous to the rpoS gene of Escherichia coli was cloned from a Pseudomonas putida KT2440 gene bank by complementation of the rpoS-deficient strainE. coli ZK918. The rpoS gene of P. putida complemented the acid sensitivity and catalase deficiency of the rpoS mutant of E. coli and stimulated expression of the RpoS-controlled promoter,bolAp 1. The gene was sequenced and found to be highly similar to the rpoS genes of other gram-negative bacteria. Like in other gram-negative bacteria, a homolog of thenlpD gene was found upstream to the rpoS gene. A transcriptional fusion of the promoter of the P. putida rpoS gene to the luxAB genes from Vibrio harveyi was constructed and used as an inactivated allele ofrpoS for gene replacement of the wild-type copy in the chromosome of P. putida. The resultantrpoS mutant of P. putida, C1R1, showed reduced survival of carbon starvation and reduced cross-protection against other types of stress in cells starved for carbon, in particular after a challenge with ethanol. Survival in soil amended with m-methylbenzoate was also reduced in the mutant strain P. putida C1R1. The RpoS protein ofP. putida controls the expression of more than 50 peptides, which are normally expressed in cells after a short period of carbon starvation.
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Richardson, AE, MA Djordjevic, BG Rolfe, and RJ Simpson. "Expression of Nodulation Genes in Rhizobium and Acid-Sensitivity of Nodule Formation." Functional Plant Biology 16, no. 1 (1989): 117. http://dx.doi.org/10.1071/pp9890117.
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The formation of nitrogen-fixing nodules on roots of leguminous plants by Rhizobium spp. involves a complex interaction between host plant and symbiont. Successful nodulation requires the coordinated expression of several nodulation (nod) genes in the bacteria. The expression of these genes is induced by flavonoid compounds present in root exudates of host plants. Growth of Rhizobium spp. and formation of nodules on roots of leguminous plants is known to be adversely affected by low pH and factors associated with soil acidity, but the basis of this acid-sensitivity is poorly understood. We consider that poor induction of nodulation gene expression in Rhizobium is a major factor contributing to the acid-sensitivity of nodulation formation. At low pH, induction of nod gene expression in R. leguminosarum biovar trifolii is markedly reduced in the presence of flavone-inducer. Furthermore, inducibility of nod gene expression in R. leguminosarum bv. trifolii is also affected by a net reduction in the concentration of nod gene-inducing factors present in the root exudates of clover seedlings grown in acidic conditions.
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Janczarek, Monika, José-María Vinardell, Paulina Lipa, and Magdalena Karaś. "Hanks-Type Serine/Threonine Protein Kinases and Phosphatases in Bacteria: Roles in Signaling and Adaptation to Various Environments." International Journal of Molecular Sciences 19, no. 10 (September 21, 2018): 2872. http://dx.doi.org/10.3390/ijms19102872.
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Reversible phosphorylation is a key mechanism that regulates many cellular processes in prokaryotes and eukaryotes. In prokaryotes, signal transduction includes two-component signaling systems, which involve a membrane sensor histidine kinase and a cognate DNA-binding response regulator. Several recent studies indicate that alternative regulatory pathways controlled by Hanks-type serine/threonine kinases (STKs) and serine/threonine phosphatases (STPs) also play an essential role in regulation of many different processes in bacteria, such as growth and cell division, cell wall biosynthesis, sporulation, biofilm formation, stress response, metabolic and developmental processes, as well as interactions (either pathogenic or symbiotic) with higher host organisms. Since these enzymes are not DNA-binding proteins, they exert the regulatory role via post-translational modifications of their protein targets. In this review, we summarize the current knowledge of STKs and STPs, and discuss how these enzymes mediate gene expression in prokaryotes. Many studies indicate that regulatory systems based on Hanks-type STKs and STPs play an essential role in the regulation of various cellular processes, by reversibly phosphorylating many protein targets, among them several regulatory proteins of other signaling cascades. These data show high complexity of bacterial regulatory network, in which the crosstalk between STK/STP signaling enzymes, components of TCSs, and the translational machinery occurs. In this regulation, the STK/STP systems have been proved to play important roles.