scholarly journals Mechanisms of Adaptation to Nitrosative Stress in Bacillus subtilis

2007 ◽  
Vol 189 (8) ◽  
pp. 3063-3071 ◽  
Author(s):  
Annika Rogstam ◽  
Jonas T. Larsson ◽  
Peter Kjelgaard ◽  
Claes von Wachenfeldt
Keyword(s):  
Bacillus Subtilis ◽  
Stress Proteins ◽  
Nitrosative Stress ◽  
Vital Role ◽  
Null Mutant ◽  
Truncated Hemoglobin ◽  
Sigma B ◽  
Nitrosonium Cation ◽  
Mechanisms Of Adaptation ◽  
Increased Sensitivity

ABSTRACT Bacteria use a number of mechanisms for coping with the toxic effects exerted by nitric oxide (NO) and its derivatives. Here we show that the flavohemoglobin encoded by the hmp gene has a vital role in an adaptive response to protect the soil bacterium Bacillus subtilis from nitrosative stress. We further show that nitrosative stress induced by the nitrosonium cation donor sodium nitroprusside (SNP) leads to deactivation of the transcriptional repressor NsrR, resulting in derepression of hmp. Nitrosative stress induces the sigma B-controlled general stress regulon. However, a sigB null mutant did not show increased sensitivity to SNP, suggesting that the sigma B-dependent stress proteins are involved in a nonspecific protection against stress whereas the Hmp flavohemoglobin plays a central role in detoxification. Mutations in the yjbIH operon, which encodes a truncated hemoglobin (YjbI) and a predicted 34-kDa cytosolic protein of unknown function (YjbH), rendered B. subtilis hypersensitive to SNP, suggesting roles in nitrosative stress management.

scholarly journals Bacillus subtilis Tolerance of Moderate Concentrations of Rifampin Involves the σB-Dependent General and Multiple Stress Response

2002 ◽  
Vol 184 (2) ◽  
pp. 459-467 ◽  
Author(s):  
Julia Elisabeth Bandow ◽  
Heike Brötz ◽  
Michael Hecker
Keyword(s):  
Bacillus Subtilis ◽  
Stress Response ◽  
Rna Polymerase ◽  
Stress Proteins ◽  
Polyacrylamide Gel Electrophoresis ◽  
Growth Arrest ◽  
Wild Type ◽  
General Stress ◽  
Inhibition Of Growth ◽  
Increased Sensitivity

ABSTRACT Low concentrations of the RNA polymerase inhibitor rifampin added to an exponentially growing culture of Bacillus subtilis led to an instant inhibition of growth. Survival experiments revealed that during the growth arrest the cells became tolerant to the antibiotic and the culture was able to resume growth some time after rifampin treatment. l-[35S]methionine pulse-labeled protein extracts were separated by two-dimensional polyacrylamide gel electrophoresis to investigate the change in the protein synthesis pattern in response to rifampin. The σB-dependent general stress proteins were found to be induced after treatment with the antibiotic. Part of the oxidative stress signature was induced as indicated by the catalase KatA and MrgA. The target protein of rifampin, the β subunit (RpoB) of the DNA-dependent RNA polymerase, and the flagellin protein Hag belonging to the σD regulon were also induced. The rifampin-triggered growth arrest was extended in a sigB mutant in comparison to the wild-type strain, and the higher the concentration, the more pronounced this effect was. Activity of the RsbP energy-signaling phosphatase in the σB signal transduction network was also important for this protection against rifampin, but the RsbU environmental signaling phosphatase was not required. The sigB mutant strain was less capable of growing on rifampin-containing agar plates. When plated from a culture that had already reached stationary phase without previous exposure to the antibiotic during growth, the survival rate of the wild type exceeded that of the sigB mutant by a factor of 100. We conclude that the general stress response of B. subtilis is induced by rifampin depending on RsbP activity and that loss of SigB function causes increased sensitivity to the antibiotic.

scholarly journals Effects of the Chromosome Partitioning Protein Spo0J (ParB) on oriC Positioning and Replication Initiation in Bacillus subtilis

2003 ◽  
Vol 185 (4) ◽  
pp. 1326-1337 ◽  
Author(s):  
Philina S. Lee ◽  
Daniel Chi-Hong Lin ◽  
Shigeki Moriya ◽  
Alan D. Grossman
Keyword(s):  
Bacillus Subtilis ◽  
Binding Sites ◽  
Fluorescent Protein ◽  
Bacterial Species ◽  
Significant Proportion ◽  
Subcellular Location ◽  
Replication Initiation ◽  
Null Mutant ◽  
Protein Ratio ◽  
Chromosome Partitioning

ABSTRACT Spo0J (ParB) of Bacillus subtilis is a DNA-binding protein that belongs to a conserved family of proteins required for efficient plasmid and chromosome partitioning in many bacterial species. We found that Spo0J contributes to the positioning of the chromosomal oriC region, but probably not by recruiting the origin regions to specific subcellular locations. In wild-type cells during exponential growth, duplicated origin regions were generally positioned around the cell quarters. In a spo0J null mutant, sister origin regions were often closer together, nearer to midcell. We found, by using a Spo0J-green fluorescent protein [GFP] fusion, that the subcellular location of Spo0J was a consequence of the chromosomal positions of the Spo0J binding sites. When an array of binding sites (parS sites) were inserted at various chromosomal locations in the absence of six of the eight known parS sites, Spo0J-GFP was no longer found predominantly at the cell quarters, indicating that Spo0J is not sufficient to recruit chromosomal parS sites to the cell quarters. spo0J also affected chromosome positioning during sporulation. A spo0J null mutant showed an increase in the number of cells with some origin-distal regions located in the forespore. In addition, a spo0J null mutation caused an increase in the number of foci per cell of LacI-GFP bound to arrays of lac operators inserted in various positions in the chromosome, including the origin region, an increase in the DNA-protein ratio, and an increase in origins per cell, as determined by flow cytometry. These results indicate that the spo0J mutant produced a significant proportion of cells with increased chromosome content, probably due to increased and asynchronous initiation of DNA replication.

Evidence for two recA genes mediating DNA repair in Bacillus megaterium

Microbiology ◽  
2005 ◽  
Vol 151 (3) ◽  
pp. 775-787 ◽  
Author(s):  
Hannes Nahrstedt ◽  
Christine Schröder ◽  
Friedhelm Meinhardt
Keyword(s):  
Escherichia Coli ◽  
Dna Repair ◽  
Mitomycin C ◽  
Bacillus Megaterium ◽  
Functional Complementation ◽  
Homologous Gene ◽  
Gene Products ◽  
Null Mutant ◽  
Promoter Regions ◽  
Increased Sensitivity

Isolation and subsequent knockout of a recA-homologous gene in Bacillus megaterium DSM 319 resulted in a mutant displaying increased sensitivity to mitomycin C. However, this mutant did not exhibit UV hypersensitivity, a finding which eventually led to identification of a second functional recA gene. Evidence for recA duplicates was also obtained for two other B. megaterium strains. In agreement with potential DinR boxes located within their promoter regions, expression of both genes (recA1 and recA2) was found to be damage-inducible. Transcription from the recA2 promoter was significantly higher than that of recA1. Since a recA2 knockout could not be achieved, functional complementation studies were performed in Escherichia coli. Heterologous expression in a RecA null mutant resulted in increased survival after UV irradiation and mitomycin C treatment, proving both recA gene products to be functional in DNA repair. Thus, there is evidence for an SOS-like pathway in B. megaterium that differs from that of Bacillus subtilis.

scholarly journals Specific and general stress proteins in Bacillus subtilis - a two-dimensional protein electrophoresis study

Microbiology ◽  
1997 ◽  
Vol 143 (3) ◽  
pp. 999-1017 ◽  
Author(s):  
J. Bernhardt ◽  
U. Volker ◽  
A. Volker ◽  
H. Antelmann ◽  
R. Schmid ◽  
...  
Keyword(s):  
Bacillus Subtilis ◽  
Stress Proteins ◽  
Protein Electrophoresis ◽  
Two Dimensional ◽  
General Stress

Induction of stress proteins by sodium chloride treatment in Bacillus subtilis

1988 ◽  
Vol 150 (6) ◽  
pp. 564-566 ◽  
Author(s):  
Michael Hecker ◽  
Christine Heim ◽  
Uwe V�lker ◽  
Lothar W�lfel
Keyword(s):  
Bacillus Subtilis ◽  
Sodium Chloride ◽  
Stress Proteins ◽  
Chloride Treatment

Signal transduction pathways initiated by catecholamines in takotsubo syndrome: focus on nitrosative stress and energetic impairment

ESC CardioMed ◽  
2018 ◽  
pp. 1283-1286
Author(s):  
John D. Horowitz ◽  
Thanh Ha Nguyen ◽  
Sven Y. Surikow ◽  
Gao Jing Ong ◽  
Cher-Rin Chong ◽  
...  
Keyword(s):  
Signal Transduction ◽  
Longitudinal Strain ◽  
Nitrosative Stress ◽  
Global Longitudinal Strain ◽  
Myocardial Inflammation ◽  
Resonance Spectroscopy ◽  
Takotsubo Syndrome ◽  
Echocardiographic Parameters ◽  
Increased Sensitivity

Takotsubo syndrome reflects an ‘aberrant’ response to acute catecholamine stimulation, largely but not entirely as a manifestation of increased sensitivity to β‎2-adrenoceptor stimulation and signal transduction via Gi proteins, especially in ageing female hearts. It is now apparent that prolonged impairment of quality of life and slow recovery of echocardiographic parameters such as global longitudinal strain after episodes of takotsubo syndrome reflect ongoing myocardial inflammation and associated oedema, together with impairment of cardiac energetics on phosphorus magnetic resonance spectroscopy.

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