Superoxide Stress Decreases Expression of srfA through Inhibition of Transcription of the comQXP Quorum-Sensing Locus in Bacillus subtilis

Ohsawa, Taku; Tsukahara, Kensuke; Sato, Tsutomu; Ogura, Mitsuo

doi:10.1093/jb/mvj023

Cited by 26 publications

(23 citation statements)

References 41 publications

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“…The second round of screening, to test the reproducibility of the decrease in transformability, was carried out by verifying the growth rates and abilities to form colonies on LB agar plates. As a result, we identified YRZDc and YUTBd in addition to the previously identified isolate SODd (a sodA disruptant [38]), in which the transformation frequency was greatly decreased (Table 3). The other disruptants identified in this screening will be described elsewhere.…”

Section: Resultsmentioning

confidence: 77%

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TheBacillus subtilisLate Competence OperoncomEIs Transcriptionally Regulated byyutBand under Post-Transcription Initiation Control bycomN(yrzD)

Ogura

Takano

2009

J Bacteriol

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The Bacillus subtilis genome has been sequenced, and disruptants with disruptions in genes that were not characterized previously were systematically generated. We screened these gene disruptants for decreased transformation frequency and identified two genes, yrzD and yutB, whose disruption resulted in severely reduced transformation frequency and modestly reduced transformation frequency, respectively. In the regulation of competence development, various signals affect the expression of comK, which encodes a master regulator of genetic competence that drives late competence gene transcription. Epistatic analyses of both the yrzD and yutB genes revealed no significant differences in the expression of comK. Further analysis of the expression of late competence genes in the yrzD disruptant revealed that yrzD is specifically required for regulation of the comE operon, which is one of the late competence operons, and thus was renamed comN. An analysis of various comE-lacZ fusions revealed that the target cis element for comN action is in the large (approximately 1-kb) 5 untranslated region of comE, while the activity of the comE promoter was not affected by disruption of comN. These results suggested that there is post-transcription initiation control of comE by comN. A sequential deletion analysis of this region revealed the 35-bp region required for comN action. The yutB gene encodes a putative lipoic acid synthetase and yet is specifically required for transcription of comE, based on the results of lacZ fusion analyses. Therefore, yutB and comN regulate comE at the transcription and post-transcription initiation levels, respectively. These results demonstrate that a comE-specific regulatory mechanism is involved in development of genetic competence.

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Section: Resultsmentioning

confidence: 77%

“…The first round of screening was performed as described previously (38). The donor DNA used was total DNA or plasmid DNA.…”

Section: Methodsmentioning

confidence: 99%

TheBacillus subtilisLate Competence OperoncomEIs Transcriptionally Regulated byyutBand under Post-Transcription Initiation Control bycomN(yrzD)

Ogura

Takano

2009

J Bacteriol

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“…Mutation in sodA , which encodes superoxide dismutase, inhibits transcription of the comQXP quorum-sensing locus, thereby preventing srfA expression [120]. At high concentrations of amino acids such as Ile, Leu, and Val, CodY represses transcription of srfA by interacting specifically with the srfA promoter [121].…”

Section: Gene Regulation In Bacillusmentioning

confidence: 99%

Diversity of Nonribosomal Peptide Synthetases Involved in the Biosynthesis of Lipopeptide Biosurfactants

Roongsawang

Washio

Morikawa

2010

IJMS

210

167

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Lipopeptide biosurfactants (LPBSs) consist of a hydrophobic fatty acid portion linked to a hydrophilic peptide chain in the molecule. With their complex and diverse structures, LPBSs exhibit various biological activities including surface activity as well as anti-cellular and anti-enzymatic activities. LPBSs are also involved in multi-cellular behaviors such as swarming motility and biofilm formation. Among the bacterial genera, Bacillus (Gram-positive) and Pseudomonas (Gram-negative) have received the most attention because they produce a wide range of effective LPBSs that are potentially useful for agricultural, chemical, food, and pharmaceutical industries. The biosynthetic mechanisms and gene regulation systems of LPBSs have been extensively analyzed over the last decade. LPBSs are generally synthesized in a ribosome-independent manner with megaenzymes called nonribosomal peptide synthetases (NRPSs). Production of active-form NRPSs requires not only transcriptional induction and translation but also post-translational modification and assemblage. The accumulated knowledge reveals the versatility and evolutionary lineage of the NRPSs system. This review provides an overview of the structural and functional diversity of LPBSs and their different biosynthetic mechanisms in Bacillus and Pseudomonas, including both typical and unique systems. Finally, successful genetic engineering of NRPSs for creating novel lipopeptides is also discussed.

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“…ROS, such as superoxide anion (O 2 ·Ϫ ), H 2 O 2 , and HO ·Ϫ , play critical and varied roles in biological processes ranging from aging and oncogenesis to pathogenesis and antibiotic action (1)(2)(3)(4). ROS act as signals at low levels but as cytotoxins at higher levels (3,(5)(6)(7)(8), so virtually all aerobic (and many anaerobic) organisms have evolved defenses for ROS detoxification. The superoxide dismutase enzymes, which catalyze disproportionation of O 2 ·Ϫ radicals, are one such important antioxidant defense (9,10).…”

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confidence: 99%

Structural, Functional, and Immunogenic Insights on Cu,Zn Superoxide Dismutase Pathogenic Virulence Factors from Neisseria meningitidis and Brucella abortus

et al. 2015

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Bacterial pathogens Neisseria meningitidis and Brucella abortus pose threats to human and animal health worldwide, causing meningococcal disease and brucellosis, respectively. Mortality from acute N. meningitidis infections remains high despite antibiotics, and brucellosis presents alimentary and health consequences. Superoxide dismutases are master regulators of reactive oxygen and general pathogenicity factors and are therefore therapeutic targets. Cu,Zn superoxide dismutases (SODs) localized to the periplasm promote survival by detoxifying superoxide radicals generated by major host antimicrobial immune responses. We discovered that passive immunization with an antibody directed at N. meningitidis SOD (NmSOD) was protective in a mouse infection model. To define the relevant atomic details and solution assembly states of this important virulence factor, we report high-resolution and X-ray scattering analyses of NmSOD and of SOD from B. abortus (BaSOD). The NmSOD structures revealed an auxiliary tetrahedral Cu-binding site bridging the dimer interface; mutational analyses suggested that this metal site contributes to protein stability, with implications for bacterial defense mechanisms. Biochemical and structural analyses informed us about electrostatic substrate guidance, dimer assembly, and an exposed C-terminal epitope in the NmSOD dimer. In contrast, the monomeric BaSOD structure provided insights for extending immunogenic peptide epitopes derived from the protein. These collective results reveal unique contributions of SOD to pathogenic virulence, refine predictive motifs for distinguishing SOD classes, and suggest general targets for antibacterial immune responses. The identified functional contributions, motifs, and targets distinguishing bacterial and eukaryotic SOD assemblies presented here provide a foundation for efforts to develop SOD-specific inhibitors of or vaccines against these harmful pathogens. IMPORTANCEBy protecting microbes against reactive oxygen insults, SODs aid survival of many bacteria within their hosts. Despite the ubiquity and conservation of these key enzymes, notable species-specific differences relevant to pathogenesis remain undefined. To probe mechanisms that govern the functioning of Neisseria meningitidis and Brucella abortus SODs, we used X-ray structures, enzymology, modeling, and murine infection experiments. We identified virulence determinants common to the two homologs, assembly differences, and a unique metal reservoir within meningococcal SOD that stabilizes the enzyme and may provide a safeguard against copper toxicity. The insights reported here provide a rationale and a basis for SOD-specific drug design and an extension of immunogen design to target two important pathogens that continue to pose global health threats.

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Superoxide Stress Decreases Expression of srfA through Inhibition of Transcription of the comQXP Quorum-Sensing Locus in Bacillus subtilis

Cited by 26 publications

References 41 publications

TheBacillus subtilisLate Competence OperoncomEIs Transcriptionally Regulated byyutBand under Post-Transcription Initiation Control bycomN(yrzD)

TheBacillus subtilisLate Competence OperoncomEIs Transcriptionally Regulated byyutBand under Post-Transcription Initiation Control bycomN(yrzD)

Diversity of Nonribosomal Peptide Synthetases Involved in the Biosynthesis of Lipopeptide Biosurfactants

Structural, Functional, and Immunogenic Insights on Cu,Zn Superoxide Dismutase Pathogenic Virulence Factors from Neisseria meningitidis and Brucella abortus

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