Adaptive Gene Expression in
            <i>Bacillus subtilis</i>
            Strains Deleted for
            <i>tetL</i>

Wei, Yi; Deikus, Gintaras; Powers, Benjamin D.; Shelden, Victor; Krulwich, Terry A.; Bechhofer, David H.

doi:10.1128/jb.00885-06

Cited by 11 publications

(9 citation statements)

References 55 publications

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“…Arginine catabolism (roc) is upregulated in the alkalinesensitive B. subtilis strain JC112 (⌬ tetL) (68), and in our array analysis, roc was strongly upregulated at high pH. The conversion of arginine to glutamate with the export of ammonia, facilitated by arginine permeases (rocC and rocE), provides a means to acidify the cytoplasm.…”

Section: Discussionmentioning

confidence: 78%

“…The conversion of arginine to glutamate with the export of ammonia, facilitated by arginine permeases (rocC and rocE), provides a means to acidify the cytoplasm. Thus, arginine uptake and breakdown to acids could help counteract base stress (68). The increase of arginine catabolism at high pH differs from the acid upregulation of arginine catabolism in other species, such as the arc operon of Streptococcus spp.…”

Section: Discussionmentioning

confidence: 99%

“…In our arrays, yhaTU showed similar upregulation during logphase growth at pH 9.0 (Table 2). Another mediator of Na ϩ flux is tetL, whose deletion decreases alkaline tolerance (14,68). Mutants containing the tetL deletion repress maeN (62), which encodes a sodium-coupled malate transporter (68).…”

Section: Figmentioning

confidence: 99%

“…At high external pH, cytoplasmic pH homeostasis involves Na ϩ /H ϩ antiporters as well as other Na ϩ transport components (14,26,50,67,68). Low pH triggers spore germination and initiation of vegetative growth (35).…”

mentioning

confidence: 99%

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Acid and Base Stress and Transcriptomic Responses in Bacillus subtilis

Wilks

Kitko

Cleeton

et al. 2009

Appl Environ Microbiol

131

148

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Acid and base environmental stress responses were investigated in Bacillus subtilis. B. subtilis AG174 cultures in buffered potassium-modified Luria broth were switched from pH 8.5 to pH 6.0 and recovered growth rapidly, whereas cultures switched from pH 6.0 to pH 8.5 showed a long lag time. Log-phase cultures at pH 6.0 survived 60 to 100% at pH 4.5, whereas cells grown at pH 7.0 survived <15%. Cells grown at pH 9.0 survived 40 to 100% at pH 10, whereas cells grown at pH 7.0 survived <5%. Thus, growth in a moderate acid or base induced adaptation to a more extreme acid or base, respectively. Expression indices from Affymetrix chip hybridization were obtained for 4,095 protein-encoding open reading frames of B. subtilis grown at external pH 6, pH 7, and pH 9. Growth at pH 6 upregulated acetoin production (alsDS), dehydrogenases (adhA, ald, fdhD, and gabD), and decarboxylases (psd and speA). Acid upregulated malate metabolism (maeN), metal export (czcDO and cadA), oxidative stress (catalase katA; OYE family namA), and the SigX extracytoplasmic stress regulon. Growth at pH 9 upregulated arginine catabolism (roc), which generates organic acids, glutamate synthase (gltAB), polyamine acetylation and transport (blt), the K ؉ /H ؉ antiporter (yhaTU), and cytochrome oxidoreductases (cyd, ctaACE, and qcrC). The SigH, SigL, and SigW regulons were upregulated at high pH. Overall, greater genetic adaptation was seen at pH 9 than at pH 6, which may explain the lag time required for growth shift to high pH. Low external pH favored dehydrogenases and decarboxylases that may consume acids and generate basic amines, whereas high external pH favored catabolism-generating acids.Bacillus subtilis can grow over several log units of environmental pH while maintaining cytoplasmic pH within a relatively narrow range that preserves protein and nucleic acid stability (19, 50, 55a). Environmental pH is important for the pathogenesis of related Bacillus species, such as the food-borne pathogen Bacillus cereus, which encounters acidic environments in the gastrointestinal tract and in food products where organic acids are used as preservatives (9, 64). B. cereus shows an acid tolerance response in which vegetative growth in a moderate acid induces proteins that enable survival under extreme acid conditions (64). In Bacillus anthracis, the lethal factor toxin undergoes a low-pH-driven structural change as it passes through acidic vesicles, which allows it to translocate into the cytosol (45). The Bacillus thuringiensis toxin is activated by alkaline pH upon entering the midgut of insect larvae (13), and bacterial growth is inhibited by acids (46).Cytoplasmic pH homeostasis has been studied extensively in B. subtilis, which maintains cytoplasmic pH within approximately pH 7.3 to pH 7.6 during vegetative growth over a range of environmental pH, from pH 6.0 to pH 9.0 (14, 50, 55a). At high external pH, cytoplasmic pH homeostasis involves Na ϩ /H ϩ antiporters as well as other Na ϩ transport components (14,26,50,67,68). Low pH triggers spore germi...

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Section: Discussionmentioning

confidence: 78%

Section: Discussionmentioning

confidence: 99%

Section: Figmentioning

confidence: 99%

mentioning

confidence: 99%

See 2 more Smart Citations

Acid and Base Stress and Transcriptomic Responses in Bacillus subtilis

Wilks

Kitko

Cleeton

et al. 2009

Appl Environ Microbiol

131

148

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“…Tetracyclines are broad-spectrum antibiotics which have been widely used in clinical, agricultural, and aquacultural settings and have seen their efficacy limited by the spread of many mechanistically different resistance determinants (19). tet(L) codes for a multifunctional efflux pump (14,19), which is involved in physiological roles such as Na ϩ resistance, K ϩ acquisition, and alkaline pH homeostasis (14,23). Surprisingly, the eight nucleotide differences observed between pLS55 and pBHS24 are located within the tet(L) gene and its regulatory regions (Fig.…”

mentioning

confidence: 99%

Tetracycline Resistance-Encoding Plasmid from Bacillus sp. Strain #24, Isolated from the Marine Sponge Haliclona simulans

Phelan

Clarke

Morrissey

et al. 2011

Appl Environ Microbiol

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Knowledge of the nature of resistance determinants in natural habitats is fundamental to increasing our understanding of the development of antibiotic resistance in clinical settings. Here we provide the first report of a tetracycline resistance-encoding plasmid, pBHS24, from a marine sponge-associated bacterium, Bacillus sp. strain #24, isolated from Haliclona simulans.The increased selection pressure created by the overuse and misuse of antibiotics in clinical and agricultural settings has undoubtedly driven the evolution and spread of resistance determinants (8, 11). While many resistance genes are believed to have their origin in natural ecosystems, their abundance, nature, and ecological role in such settings remain relatively obscure (2). It is nevertheless accepted that this knowledge is fundamental to tackle the ingenious ways that bacteria curtail the effectiveness of antimicrobial agents.Research on marine sponge-associated bacteria has increased exponentially in recent years, but this has focused predominantly on phylogeny and on the search for novel bioactive compounds (13,22). While much data are available on the microbial ecology of marine sponges (12, 22), comparatively little is known about the incidence and diversity of antibiotic resistance determinants and the often associated mobile elements among these bacteria.We have recently characterized the spore-forming population of the marine sponge Haliclona simulans, collected from Gurraig Sound, Kilkieran Bay, Galway, Ireland. One of the isolates was identified by partial 16S rRNA gene sequencing as a Bacillus sp., with 96% sequence identity to its closest relative, Bacillus lehensis. Bacillus sp. strain #24 was unable to grow in SYP (12) and LB media unless supplemented with either 50% artificial seawater (12) or 2% NaCl and was resistant to tetracycline and erythromycin (MICs of 75 g ml Ϫ1 and 3 mg ml Ϫ1 , respectively. MIC values reported in this study are defined as the minimal concentration of antibiotic able to inhibit the growth of the strains when spotted on Muller-Hinton medium plates containing increasing concentrations of the antibiotic). Screening of isolate #24 for plasmid DNA (6) was positive, with multiple bands visible on agarose gels. In order to ascertain its role in antibiotic resistance, total plasmid DNA purified from isolate #24 (QIAprep Spin miniprep kit optimized for Bacillus; Qiagen GmbH) was used to transform Bacillus subtilis 168 competent cells. This strain is sensitive to erythromycin and displays only a very low level of resistance to tetracycline (2 g ml Ϫ1 ) associated with the presence of a chromosomally carried tet(L) gene (9, 20). B. subtilis 168 is easily differentiated from isolate #24 by colony morphology (Fig. 1). A large number of transformants were obtained on LB medium-tetracycline plates, while no colonies grew on those containing erythromycin (both at 5 g ml Ϫ1 ). This implied that tetracycline resistance was associated with plasmid DNA, while erythromycin resistance was probably chromosomally encoded. A...

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Microarray Studies in Bacillus subtilis

Kocabaş

Çalı́k

Çalık

et al. 2009

Biotechnology Journal

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This review focuses on the construction of a global, comprehensive understanding of Bacillus subtilis through microarray studies. The microarray studies in B. subtilis were analysed based on the theme of the work, by mentioning the growth media, bioreactor operation conditions, RNA isolation method, number of data points analysed in exponential or stationary phases, compared genotypes, induction and repression ratios, investigated gene(s) and their positive and/or negative influences. Based on the theme and scope of the studies, the articles were reviewed under seven thematic sections, i.e., effects of gene deletion(s) or overexpression, effects of overexression of heterologous genes, comparison of global gene expression between aerobic and anaerobic respiration, effects of temperature change, effects of transported molecules, effects of limitations and stress conditions, and other microarray studies in B. subtilis.

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Adaptive Gene Expression in Bacillus subtilis Strains Deleted for tetL

Cited by 11 publications

References 55 publications

Acid and Base Stress and Transcriptomic Responses in Bacillus subtilis

Acid and Base Stress and Transcriptomic Responses in Bacillus subtilis

Tetracycline Resistance-Encoding Plasmid from Bacillus sp. Strain #24, Isolated from the Marine Sponge Haliclona simulans

Microarray Studies in Bacillus subtilis

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