sigma factors in the sigma(70) family can be classified into the primary and alternative sigma factors according to their physiological functions and amino acid sequence similarities. The primary sigma factors are composed of four conserved regions, with the conserved region 1 being divided into two subregions. Region 1.1, which is absent from the alternative sigma factor, is poor in conservati...

Two genes of the sigB operon, rsbU and rsbV, were deleted in an rsbU(+) strain (FDA486) to evaluate the contribution of these two genes to sigma(B) activity in Staphylococcus aureus. The sigma(B) protein level and the transcription of two sigma(B)-dependent promoters (sigB and sarA P3 transcripts) were analyzed in the constructed mutants. A deletion of the first gene (rsbU) within the sigB oper...

Extracytoplasmic function or ECF sigma factors are the most abundant class of alternative sigma factors in bacteria. Members of the rpoE subclass of ECF sigma factors are implicated in sensing stress in the cell envelope of Gram-negative bacteria and are required for virulence in many pathogens. The best-studied member of this family is rpoE from Escherichia coli, encoding the sigma(E) protein....

Sigma (sigma) receptors, initially described as a subtype of opioid receptors, are now considered unique receptors. Pharmacological studies have distinguished two types of sigma receptors, termed sigma(1) and sigma(2). Of these two subtypes, the sigma(1) receptor has been cloned in humans and rodents, and its amino acid sequence shows no homology with other mammalian proteins. Several psychoact...

Sigma-1 receptor antagonists promote antinociception in several models of pain, but the effects of sigma-1 agonists on nociception (particularly when the nociceptive system is primed) are not so well characterized; therefore we evaluated the effects of sigma-1 agonists on pain under different experimental conditions. The systemic administration of the selective sigma-1 agonists (+)-pentazocine ...

We study the distribution P(sigma) of the equivalent conductance sigma for Erdös-Rényi (ER) and scale-free (SF) weighted resistor networks with N nodes. Each link has conductance g triple bond e-ax, where x is a random number taken from a uniform distribution between 0 and 1 and the parameter a represents the strength of the disorder. We provide an iterative fast algorithm to obtain P(sigma) an...

BACKGROUND Sigma-1 receptors are involved in regulation of neuronal activities presumably through regulation of the activity of ion channels. Sigma-1 receptors also play a role in growth and metastasis of cancerous cells. Intracellular distribution of sigma-1 receptors have been linked to sphingolipid-enriched domains. RESULTS We report that in CHO-K1 cells sigma-1 receptors target to focal a...

RNA polymerase sigma factor sigma(F) initiates the prespore-specific program of gene expression during Bacillus subtilis sporulation. sigma(F) governs transcription of spoIIIG, encoding the late prespore-specific regulator sigma(G). However, transcription of spoIIIG is delayed relative to other genes under the control of sigma(F), and after synthesis, sigma(G) is initially kept in an inactive f...