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Sigma Factor (0):
Recent article
Sigma Factor
Abstract
We have identified in C. thermocellum a set of putative σ and anti-σ factors that include extracellular polysaccharide-sensing components [Kahel-Raifer et al. (2010) FEMS Microbiol Lett 308:84-93]. These factor-encoding genes are homologous to the Bacillus subtilis bicistronic operon sigI-rsgI, wh...
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PMID: 20937888
PDF is available here.
PDF is available here.
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Trends in Microbiology (18)10 2010
Abstract
Investigators have recently turned to the soil nematode Caenorhabditis elegans as a small animal infection model to study infectious disease. To extrapolate findings concerning bacterial pathogenesis from non-mammals to mammals, virulence factors should be conserved in function, independent of the i...
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PMID: 20667738
PDF is available here.
PDF is available here.
Infection and Immunity (78)8 2010
Abstract
We showed that the pknB gene (also called stk1) of methicillin-resistant S. aureus (MRSA) strain COL and the community-acquired MRSA (CA-MRSA) strain USA300 is involved in cell wall metabolism, with the pknB mutant exhibiting enhanced sensitivity to beta-lactam antibiotics but not to other classes o...
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PMID: 20547748
PDF is available here.
PDF is available here.
Abstract
Conditions that sustain constant bacterial growth are seldom found in nature. Oligotrophic environments and competition among microorganisms force bacteria to be able to adapt quickly to rough and changing situations. A particular lifestyle composed of continuous cycles of growth and...
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PMID: 20236330
PDF is available here.
PDF is available here.
Abstract
We determined whether growth in differing NaCl concentrations alters the susceptibility of V. parahaemolyticus O3:K6 to other environmental stresses. Vibrio parahaemolyticus was grown at a 1% or 3% NaCl concentration, and the growth and survival of the organism were examined under acid or temperatur...
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PMID: 20472729
PDF is available here.
PDF is available here.
Infection and Immunity (78)7 2010
Abstract
We analyze the potential use of an attenuated mutant of Mycobacterium tuberculosis H37Rv lacking the sigma factor sigma(E) as a live vaccine. We have demonstrated that BALB/c mice infected by the intratracheal route with this mutant strain showed significantly higher survival rates and less tissue d...
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PMID: 20457786
PDF is available here.
PDF is available here.
Infection and Immunity (78)7 2010
Abstract
We show that ferritin-like proteins (Frl) are highly conserved in the genus Listeria and demonstrate that these proteins are present in both the cytoplasm and cell wall fractions of these bacteria. Even though Frl is expressed under different growth conditions, transcriptional mapping revealed that...
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PMID: 20439472
PDF is available here.
PDF is available here.
Abstract
Burkholderia pseudomallei, the causative agent of the potentially fatal tropical disease melioidosis, is known to be highly resistant to oxidative stress although the mechanism of this resistance remains to be fully elucidated. Previous studies have shown that an OxyR is involved in the regulation o...
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PMID: 20618685
PDF is available here.
PDF is available here.
Journal of Bacteriology (192)14 2010
Abstract
RpoS, Escherichia coli's general stress response sigma factor, regulates error-prone DNA polymerase IV (Pol IV) (encoded by the dinB gene). Pol IV is induced in stationary-phase cells, and thereafter, levels of the protein remain elevated for several days of continuous incubation. This induction and...
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PMID: 20472798
PDF is available here.
PDF is available here.
Journal of Bacteriology (192)14 2010
Abstract
We demonstrate that the putative -35 hexamer is dispensable for ExsA-independent transcription from the P(exsC) promoter and that deletion of sigma(70) region 4.2, which contacts the -35 hexamer, has no effect on ExsA-independent transcription from P(exsC). Region 4.2 of sigma(70), however, is requi...
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PMID: 20453093
PDF is available here.
PDF is available here.
Abstract
We have adopted a practical approach to successfully improve avermectin production in an industrial overproducer. Transcriptional levels of the wild-type strain and industrial overproducer in production cultures were monitored using microarray analysis. The avermectin biosynthetic genes, especially...
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PMID: 20534557
PDF is available here.
PDF is available here.
Abstract
We have found that the phosphorylation of SIG1, the major sigma factor (SIG), is regulated by redox signals and selectively inhibits the transcription of the psaA gene, which encodes a PS-I protein. We produced transgenic Arabidopsis plants with or without the putative phosphorylation sites for SIG1...
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PMID: 20498041
PDF is available here.
PDF is available here.
Antonie Van Leeuwenhoek (98)1 2010
Abstract
We investigated surA and fkpA, encoding two different classes of peptidyl-prolyl isomerase that function in folding cell envelope proteins. Both surA and fkpA are members of the heat-shock-inducible sigma(E) regulon of Escherichia coli. Although both genes are expressed in C-starved Salmonella cells...
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PMID: 20232248
PDF is available here.
PDF is available here.
Biotechnology Letters (32)6 2010
Abstract
Gene expression system Hsh is developed to increase enzyme production and to decrease the cost in the induction of gene expression in Escherichia coli. The vectors of Hsh system were constructed by combining a synthesized heat-shock promoter with a synthesized terminator and an origin of replication...
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PMID: 20155484
PDF is available here.
PDF is available here.
Microbial Pathogenesis (48)6 2010
Abstract
We found that disruption of the varS gene, a member of the recently reported sensory system VarS/VarA-CsrA/B/C/D, resulted in altered expression of hemagglutinin/protease A. To further investigate the connection between VarS and HapA, we generated an additional varS mutant, V. cholerae 2740-80-VS, a...
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PMID: 20307644
PDF is available here.
PDF is available here.
Biosystems (100)3 2010
Abstract
We systematically surveyed the effect of these two factors on sporulation using a quantitative modeling and simulation architecture named hybrid functional Petri net with extension (HFPNe). Considering the fact that the transient genetic asymmetry and the volume difference in sporulation of B. subti...
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PMID: 20298743
PDF is available here.
PDF is available here.
Microbiology (156)Pt 6 2010
Abstract
We isolated genes which, when supplied in multicopy, suppress the repression of flhD, and found that three genes, gadW, metE and yeaB, were capable of suppression. Taking into account a previous report that gadW represses sigma(S) production, the level of sigma(S) in the pgsA3 mutant was examined. W...
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PMID: 20185506
PDF is available here.
PDF is available here.
Microbiology (156)Pt 6 2010
Abstract
We determine the global response to diamide in wild-type and sigR mutant backgrounds to understand the role of sigma(R) in this response and to reveal additional regulatory pathways that allow cells to cope with disulphide stress. In addition to thiol oxidation, diamide was found to cause protein mi...
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PMID: 20185507
PDF is available here.
PDF is available here.
Microbiology (156)Pt 6 2010
Abstract
We show the importance of the alternative sigma factor RpoE2 in Sinorhizobium meliloti osmoadaptation. Construction and characterization of an S. meliloti rpoE2 mutant revealed compromised growth in hyperosmotic media. This defect was due to the lack of trehalose, a minor carbohydrate osmolyte norma...
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PMID: 20223801
PDF is available here.
PDF is available here.
Journal of Bacteriology (192)12 2010
Abstract
We investigated here the role of AlgU in the formation of nonmucoid biofilms. The algU mutant of P. aeruginosa PAO1 (PAOU) showed a dramatic impairment in biofilm formation under dynamic conditions. PAOU was defective both in cell attachment to glass and in development of robust, shear-resistant bio...
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PMID: 20348252
PDF is available here.
PDF is available here.
Journal of Bacteriology (192)12 2010
Abstract
We used laser capture microdissection (LCM) and quantitative reverse transcription (RT)-PCR to target defined biofilm subpopulations for gene expression studies. Here, we combined this approach with quantitative PCR of bacterial DNA to normalize the amount of gene expression per cell. By comparing t...
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PMID: 20348255
PDF is available here.
PDF is available here.
Abstract
We show that both Hfq and this Hfq binding site are required for RprA or ArcZ to act in vivo and to form a stable complex with rpoS mRNA in vitro; both were partially dispensable for DsrA at 37 degrees C. ArcZ sRNA is processed from 121 nt to a stable 56 nt species that contains the pairing region;...
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PMID: 20457943
PDF is available here.
PDF is available here.
Genetika (Moskva) (46)5 2010
Abstract
Most bacteria exist in the natural environment as biofilms, multicellular communities attached to hard surfaces. Biofilms have a characteristic architecture and are enclosed in the exopolymer matrix. Bacterial cells in biofilms are extremely resistant to antibacterial factors. It was shown in this w...
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PMID: 20583596
PDF is available here.
PDF is available here.
Microbiology (156)Pt 4 2010
Abstract
We determined that P. aeruginosa is dependent upon aceA, which encodes ICL, to cause disease on alfalfa seedlings and in rat lungs. Expression of aceA in PAO1, a P. aeruginosa isolate associated with acute infection, is regulated by carbon sources that utilize the glyoxyate pathway. In contrast, exp...
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PMID: 20093293
PDF is available here.
PDF is available here.
Abstract
In KMB or PPM medium, beta-galactosidase activity of phzl'-'lacZ in the mutant PA-SG is much more than that in the wild type strain. However, beta-galactosidase activity of phz2'-'lacZ in the wild type strain is 2 -3 folds more than that in the mutant PA-SG. CONCLUSION: With these results, it is sug...
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PMID: 20499649
PDF is available here.
PDF is available here.
Abstract
We report a global and quantitative analysis of staphylococcal cell surface-associated proteins using a combination of (14)N(15)N metabolic labeling, biotinylation, and GeLC-MS/MS. To address the important question of S. aureus pathophysiology, we analyzed the influence of the alternative sigma fact...
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PMID: 20108986
PDF is available here.
PDF is available here.
Abstract
We have demonstrated that it exits as a monomer in solution, possesses multiple domains, harbors primarily alpha-helix and efficiently binds to a S. aureus promoter DNA in the presence of core RNA polymerase. While both N- and C-terminal ends of His- sigma(A) are flexible in nature, two Trp residues...
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PMID: 20356457
PDF is available here.
PDF is available here.
Abstract
Aerobic growth conditions significantly influenced anaerobic succinate production in two-stage fermentation by Escherichia coli AFP111 with knockouts in rpoS, pflAB, ldhA, and ptsG genes. At a low cell growth rate limited by glucose, enzymes involved in the reductive arm of the tricarboxylic acid cy...
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PMID: 20038712
PDF is available here.
PDF is available here.
Journal of Bacteriology (192)3 2010
Abstract
We use a reporter-gene fusion to show that sigma(B) can also be activated by red light via the energy branch of its upstream signaling cascade. Deletion mutagenesis and homologous overproduction experiments indicate that the RsbP protein (composed of an N-terminal Per-ARNT-Sim [PAS] domain and a C-t...
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PMID: 19948797
PDF is available here.
PDF is available here.
Journal of Bacteriology (192)4 2010
Abstract
We also used a bacterial two-hybrid system (BACTH) to show that the four substitutions in Crl abolish Crl-sigma(S) interaction and that residues 1 to 71 in sigma(S) are dispensable for Crl binding. In Escherichia coli, it has been reported that Crl also interacts with the ferric uptake regulator Fur...
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PMID: 20008066
PDF is available here.
PDF is available here.
Journal of Bacteriology (192)3 2010
A comprehensive proteomics and transcriptomics analysis of Bacillus subtilis salt stress adaptation.
Abstract
We applied whole-genome microarray technology and metabolic labeling, combined with state-of-the-art proteomic techniques, to provide a global and time-resolved picture of the physiological response of B. subtilis cells exposed to a severe and sudden osmotic upshift. This combined experimental appro...
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PMID: 19948795
PDF is available here.
PDF is available here.
Science progress (93)Pt 1 2010
Abstract
The complex physical and chemical conditions encountered in the gut present a range of physiological challenges to both the commensal microbiota and to pathogenic microorganisms attempting to colonise the gut. The innate immune system of the host, the host's diet and the microbial population present...
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PMID: 20222354
PDF is available here.
PDF is available here.
Salud Publica de Mexico (52)1 2010
Abstract
Mycobacterium tuberculosis, the causal agent of tuberculosis, has affected humankind for approximately 20,000 years. Tuberculosis is a devastating disease, particularly in developing countries. One of its most notable characteristics is latent infection, in which live bacilli persist in the host tis...
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PMID: 20464256
PDF is available here.
PDF is available here.
Abstract
We show that deletion of polyphosphate kinase (PPK), the principal enzyme responsible for synthesis of polyP, resulted in augmented expression of cAMP receptor protein (CRP) and rpoS and lowered H2O2 sensitivity in Salmonella Typhimurium ATCC14028. The binding of cAMP-CRP complex to rpoS promoter an...
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PMID: 20075614
PDF is available here.
PDF is available here.
Abstract
A transcriptional fusion (opgG1::MudJ) to the opgGH operon of Salmonella enterica serovar Typhimurium (S. Typhimurium) LT2, isolated by resistance to mecillinam, was used to study the influence of global regulators RpoS, ppGpp, and cAMP/cAMP-receptor protein (CRP) on expression of the opgGH operon a...
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PMID: 19940937
PDF is available here.
PDF is available here.
Abstract
The survival of and interactions between a Pseudomonas putida strain labelled with a red fluorescent protein gene (WT-rfp) and its green fluorescent protein gene-labelled rpoS(-) mutant (KO-gfp) were examined. The generation times of the planktonic WT-rfp and KO-gfp in trypticase soy broth were not...
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PMID: 19935890
PDF is available here.
PDF is available here.
Leprosy Review (80)3 2009
Abstract
Analysis for rpoT genotyping of 64 samples collected in the west and southwestern areas revealed that 46 isolates were of the 4 copy type and 18 isolates were of the 3 copy type. All samples from the eastern coastal area (n = 24) and from the Yucatan peninsula (n = 12) were of the 3 copy type. Six i...
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PMID: 19961105
PDF is available here.
PDF is available here.
Abstract
We investigated the impact of sigma B on sarA transcription and biofilm formation in three independent S. epidermidis isolates. Mutants with dysfunctional sigma B displayed a strongly reduced biofilm formation, whereas in mutants with constitutive sigma B activity biofilm formation was increased. Tr...
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PMID: 19856270
PDF is available here.
PDF is available here.
Microbiology (155)Pt 8 2009
Abstract
We show that FTL_0851 encodes a genuine sigma(32) factor. Transcriptomic analyses of the F. tularensis LVS heat-stress response allowed the identification of a series of orthologues of known heat-shock genes (including those for Hsp40, GroEL, GroES, DnaK, DnaJ, GrpE, ClpB and ClpP) and a number of g...
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PMID: 19443547
PDF is available here.
PDF is available here.
Microbiology (155)Pt 7 2009
Abstract
These results suggest that: (i) Vfr enhances toxA expression in PAO1 both directly and indirectly through regA, but not through pvdS; (ii) vfr expression is not regulated by iron; and (iii) both Vfr and PvdS cooperate in the presence of RegA to achieve a maximum level of toxA expression....
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PMID: 19389782
PDF is available here.
PDF is available here.
Phytopathology (99)6 2009
Abstract
We detected a frameshift mutation in the rpoS of A506 and demonstrated that the mutation resulted in a truncated, nonfunctional RpoS. Using site-directed mutagenesis, we deleted a nucleotide from rpoS, which then encoded a full-length, functional RpoS. We compared the stress response and epiphytic f...
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PMID: 19453226
PDF is available here.
PDF is available here.
Phytopathology (99)6 2009
Abstract
Bacteria living epiphytically on aerial plant surfaces encounter severe and rapidly fluctuating environmental conditions, and their capacity to withstand environmental stress contributes to epiphytic fitness. The stationary phase sigma factor RpoS is a key determinant in stress response of gram-nega...
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PMID: 19453227
PDF is available here.
PDF is available here.
Abstract
Mycobacterium ulcerans is the causative agent of the Buruli ulcers in humans. This disease is a devastating necrotic disease of the subcutaneous tissue. Currently there are very few drugs to prevent the Buruli ulcers. This human pathogen is carried by aquatic insects. The gene sequence of this patho...
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PMID: 18454323
PDF is available here.
PDF is available here.
Journal of Bacteriology (191)10 2009
Abstract
We considered the hypothesis that the rapid decay of competence arises from a rapid loss of ComW and thus of its ComX stimulating activity, so that ComX might persist but lose its transcriptional activity. Western analysis revealed that ComW is indeed a transient protein, which is also stabilized by...
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PMID: 19286798
PDF is available here.
PDF is available here.
Abstract
We characterized the physiological and transcriptional responses of N. europaea cells to cyanide. The cells were extremely sensitive to low concentrations of cyanide, with NO-(2)production and ammonia-dependent oxygen uptake rates decreasing by 50% within 30 min of exposure to 1 microM NaCN. Whole-g...
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PMID: 19072843
PDF is available here.
PDF is available here.
Abstract
We found that the H subunit of Mg-chelatase ChlH interacts with sigma factor SigE by yeast two-hybrid screening, and immunoprecipitation analysis revealed that ChlH associates with SigE in a light-dependent manner in vivo. We also found that Mg(2+) promotes the interaction of SigE and ChlH and deter...
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PMID: 19342483
PDF is available here.
PDF is available here.
Microbiology (155)Pt 4 2009
Abstract
We showed that inactivation of a kinase (KinB) in nonmucoid strain PAO1 results in overproduction of alginate. Here, we report the initial characterization of lipotoxin F (LptF, PA3692), an OmpA-like outer membrane protein that exhibited increased expression in the mucoid PAO1kinB mutant. The lipoto...
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PMID: 19332805
PDF is available here.
PDF is available here.
Molecular Microbiology (72)1 2009
Abstract
We hypothesized that the ability to store carbon as glycogen would facilitate both bacterial fitness in the aquatic environment and transmission of V. cholerae to new hosts. To investigate the role of glycogen in V. cholerae transmission, we constructed mutants that cannot store or degrade glycogen....
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PMID: 19226328
PDF is available here.
PDF is available here.
Molecular Microbiology (72)1 2009
Abstract
We have shown that cell wall stress (e.g. d-cycloserine) is a potent inducer of the algD operon. Here we showed that MucB, encoded by the algT-mucABCD operon, interacts with MucA in the sigma-sequestration complex. We hypothesized that AlgW protease (a DegS homologue) is activated by cell wall stres...
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PMID: 19226327
PDF is available here.
PDF is available here.
Molecular Microbiology (72)2 2009
Abstract
We show that specific peptides bind to the periplasmic AlgW protease and activate its cleavage of MucA. We demonstrate that tight binding of MucB to MucA strongly inhibits this cleavage. We also probe the roles of structural features of AlgW, including a key regulatory loop and its PDZ domain, in re...
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PMID: 19298369
PDF is available here.
PDF is available here.
Infection and Immunity (77)4 2009
Abstract
We mutagenized S. aureus strain SH1000 to identify loci essential for ica-independent mechanisms of biofilm maturation and identified multiple insertions in the rsbUVW-sigB operon. Following construction and characterization of a sigB deletion, we determined that the biofilm phenotype was due to a l...
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PMID: 19188357
PDF is available here.
PDF is available here.
Plant Molecular Biology (69)5 2009
Abstract
We show that Arabidopsis CSP41a and CSP41b interact in vivo, and that a csp41b null mutant becomes depleted of CSP41a in mature leaves, correlating with a pale green phenotype and reduced accumulation of the ATP synthase and cytochrome b ( 6 )/f complexes. RNA gel blot analyses revealed up to four-f...
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PMID: 19067181
PDF is available here.
PDF is available here.
Molecular Microbiology (71)5 2009
Abstract
We have identified a new osmoregulation gene, osaC, encoding a member of a novel family of regulatory proteins. Members of the family have a predicted domain composition consisting of an N-terminal kinase domain related to anti-sigma factors, sensory Pas and Gaf domains, and a C-terminal phosphatase...
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PMID: 19154327
PDF is available here.
PDF is available here.
Molecular Microbiology (71)5 2009
Abstract
We show that sigma(E) in Salmonella enterica sv. Typhimurium can also be activated by acid stress. A sigma(E)-deficient mutant exhibits increased susceptibility to acid pH and reduced survival in an acidified phagosomal vacuole. Acid activation of sigma(E)-dependent gene expression is independent of...
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PMID: 19170886
PDF is available here.
PDF is available here.
Genes & Genetic Systems (84)1 2009
Abstract
SsrA is a small RNA playing a crucial role in trans-translation, which leads to rescue of stalled ribosomes on or at the end of mRNA and addition of the degradation tag to a growing polypeptide. The lack of SsrA has been shown to enhance the temperature-sensitive (ts) phenotype of an E. coli strain...
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PMID: 19420797
PDF is available here.
PDF is available here.
Journal of Molecular Biology (385)2 2009
Abstract
Bacterial RNA polymerase and a "sigma" transcription factor form an initiation-competent "open" complex at a promoter by disruption of about 14 base pairs. Strand separation is likely initiated at the highly conserved -11 A-T base pair. Amino acids in conserved region 2.3 of the main Escherichia col...
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PMID: 18976666
PDF is available here.
PDF is available here.
RNA Biology (6)5 2009
Abstract
We analyzed the turn-over of OxyS and rpoS mRNA in early exponential and in stationary growth phase in different E. coli strains to learn more about the mechanisms of processing and about a possible impact of processing on growth-dependent regulation. We could not attribute a major role of RNase E,...
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PMID: 20016254
PDF is available here.
PDF is available here.
Abstract
The distribution of the electrostatic potential of T7 bacteriophage genome has been calculated. Promoter sites were localized in the electrostatic profile of T7-DNA. The electrostatic patterns of sigma70-specific promoters interacting with Escherichia coli RNA-polymerase were analyzed and compared w...
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PMID: 20067173
PDF is available here.
PDF is available here.
Abstract
Inactivation of the rpoS gene encoding for sigma S subunit of RNA polymerase of the rhizospheric strain Pseudomonas chlororaphis 449 results in a sharp decrease (5-8 fold) of phenazine antibiotics synthesis, decline of acid and alkaline phosphatases (pH 2.5 and 8.8, respectively) activities and anta...
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PMID: 19283908
PDF is available here.
PDF is available here.
Abstract
We found that oxygen negatively regulates biofilm development by influencing the activity of sigma(B). Under anaerobic conditions, increased sigma(B) activity activates icaADBC, which encodes enzymes responsible for polysaccharide intercellular adhesin synthesis, by repressing transcription of the n...
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PMID: 19011058
PDF is available here.
PDF is available here.