background: sigma factors are proteins that regulate transcription in bacteria. sigma factors can be activated in response to different environmental conditions. the rpos (rna polymerase, sigma s) gene encodes sigma-38 (σ38, or rpos), a 37.8 kda protein in pseudomonas aeruginosa (p. aeruginosa) strains. rpos is a central regulator of the general stress response and operates in both retroactive ...

In this paper, at first for a given set of real or complex numbers $sigma$ with nonnegative summation, we introduce some special conditions that with them there is no nonnegative tridiagonal matrix in which $sigma$ is its spectrum. In continue we present some conditions for existence such nonnegative tridiagonal matrices.

Two sigma factors, sigma 35 and sigma 28, direct transcription from the Bt I and Bt II promoters of the cryIA(a) gene of Bacillus thuringiensis; this gene encodes a lepidopteran-specific crystal protoxin. These sigma factors were biochemically characterized in previous work (K. L. Brown and H. R. Whiteley, Proc. Natl. Acad. Sci. USA 85:4166-4170, 1988; K. L. Brown and H. R. Whiteley, J. Bacteri...

As Bacillus subtilis proceeds through sporulation, the principal vegetative cell sigma subunit (sigma(A)) persists in the cell but is replaced in the extractable RNA polymerase (RNAP) by sporulation-specific sigma factors. To explore how this holoenzyme changeover might occur, velocity centrifugation techniques were used in conjunction with Western blot analyses to monitor the associations of R...

The production of extracellular enzymes by Pseudomonas fluorescens is important with respect to phytopathogenesis and, in the case of psychrotrophic strains, food spoilage. The production of extracellular protease has been previously reported to be dependent on temperature in psychrotrophic strains of P. fluorescens; production is decreased above the optimum growth temperature with a relatively...

OBJECTIVES Our previous studies demonstrated autonomic nervous system disorders and cerebral blood hypoperfusion in school refusal students with underlying emotional distress due to fear or anxiety associated with school attendance. Because severe stress is known to affect glucoregulatory metabolism, this study used the oral glucose tolerance test (OGTT) to measure glucose metabolism in school ...