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Bacillus subtilis produces and exports a peptide sporulation killing factor (SkfA) that induces lysis of sibling cells, skfA is part of the skf operon (skfA-H), which is responsible for immunity to SkfA, as well as for production and export of SkfA. Here we report that transcription ofskfA is markedly induced when cells of B. subtilis are subjected to phosphate starvation. The role of PhoP in regulation of the skf operon was confirmed by in vitro gel shift assays, which showed that this operon is a new member of the PhoP regulon. A putative stem-loop structure in the skfA-skfB intergenic region is proposed to act as a stabilizer of an skfA-specific transcript.

Bacillus subtilis responds to phosphate starvation stress by inducing the PhoP and SigB regulons. While the PhoP regulon provides a specific response to phosphate starvation stress, maximizing the acquisition of phosphate ([P.sub.i]) from the environment and reducing the cellular requirement for this essential nutrient, the SigB regulon provides nonspecific resistance to stress by protecting essential cellular components, such as DNA and membranes. We have characterized the phosphate starvation stress response of B. subtilis at a genome-wide level using DNA macroarrays. A combination of outlier and cluster analyses identified putative new members of the PhoP regulon, namely, yfkN (2',3' cyclic nucleotide 2'-phosphodiesterase), yurI (RNase), yjdB (unknown), and vpr (extracellular serine protease). YurI is thought to be responsible for the nonspecific degradation of RNA, while the activity of YfkN on various nucleotide phosphates suggests that it could act on substrates liberated by YurI, which produces 3' or 5' phosphoribonucleotides. The putative new PhoP regulon members are either known or predicted to be secreted and are likely to be important for the recovery of inorganic phosphate from a variety of organic sources of phosphate in the environment.

During phosphate starvation, Bacillus subtilis regulates genes in the PhoP regulon to reduce the cell's requirement for this essential substrate and to facilitate the recovery of inorganic phosphate from organic sources such as teichoic and nucleic acids. Among the proteins that are highly induced under these conditions is PstS, the phosphate-binding lipoprotein component of a high-affinity ABC-type phosphate transporter. PstS is encoded by the first gene in the pst operon, the ether four members of which encode the integral membrane and cytoplasmic components of the transporter. The transcription of the pst operon was analysed using a combination of methods, including transcriptional reporter gene technology, Northern blotting and DNA arrays. It is shown that the primary transcript of the pst operon is processed differentially to maintain higher concentrations of PstS relative to other components of the transporter. The comparative studies have revealed limitations in the use of reporter gene technology for analysing the transcription of operons in which the messenger RNA transcript is differentially processed.

When Bacillus subtilis is subjected to phosphate starvation, the Pho regulon is activated by the PhoP-PhoR two-component signal transduction system to elicit specific responses to this nutrient limitation. The response regulator, PhoP, and its cognate histidine sensor kinase, PhoR, are encoded by the phoPR operon that is transcribed as a 2.7-kb bicistronic mRNA. ThephoPR operon is transcribed from two [[sigma].sup.A]-dependent promoters, [P.sub.l] and [P.sub.2]. Under conditions where the Pho regulon was not induced (i.e., phosphate-replete conditions or phoR-null mutant), a low level of phoPR transcription was detected only from promoter [P.sub.l]. During phosphate starvation-induced transition from exponential to stationary phase, the expression of the phoPR operon was up-regulated in a phosphorylated PhoP (PhoP~P)-dependent manner; in addition to [P.sub.1], the [P.sub.2] promoter becomes active. In vitro gel shift assays and DNase I footprinting experiments showed that both PhoP and PhoP~P could bind to the control region of the phoPR operon. The data indicate that while low-level constitutive expression of phoPR is required under phosphate-replete conditions for signal perception and transduction, autoinduction is required to provide sufficient PhoP~P to induce other members of the Pho regulon. The extent to which promoters [P.sub.1] and [P.sub.2] are activated appears to be influenced by the presence of other sigma factors, possibly the result of sigma factor competition. For example, phoPR is hyperinduced in a sigB mutant and, later in stationary phase, in sigH, sigF, and sigE mutants. The data point to a complex regulatory network in which other stress responses and post-exponential-phase processes influence the expression of phoPR and, thereby, the magnitude of the Pho regulon response.

Research has been conducted on Salmonella enterica serovar Typhimurium nonculturable cells. The hypothesis that these cells may be the source for infective disease has been investigated and the results are reported.

Research has been conducted on the genes responding to phosphate starvation. These genes have been assigned to the Pho and sigma (super)B -dependent general stress regulons via monitoring their expression in phoR-null or sigB-null mutants and the details are discussed.

The degree to which teichoic acids in the cell wall of Bacillus subtilis are alanylated determines the secretion of recombinant protective antigen of Bacillus anthracis. Protective antigen is used to create the anthrax vaccine so researchers are interested in creating a recombinant form in Bacillus subtilis. This will eliminate trace amounts of other proteins that can cause an adverse reaction to the vaccine.

Results show that in the absence of the sodium-hydrogen ion antiporter, NhaC, the phoPR operon and alkaline phosphatase genes are hyperinduced and they are repressed when NhaC is overproduced. Data indicate that alkaline production is controlled by Nhac through phoPR operon.

Because the majority of bacterial species divide by binary fission, and do not have distinguishable somatic and germline cells, they could be considered to be immortal. However, bacteria 'age' due to damage to vital cell components such as DNA and proteins. DNA damage can often be repaired using efficient DNA repair mechanisms. However, many proteins have a functional 'shelf life'; some are short lived, while others are relatively stable. Specific degradation processes are built into the life span of proteins whose activities are required to fulfil a specific function during a prescribed period of time (e.g. cell cycle, differentiation process, stress response). In addition, proteins that are irreparably damaged or that have come to the end of their functional life span need to be removed by quality control proteases. Other proteases are involved in performing a variety of specific functions that can be broadly divided into three categories: processing, regulation and feeding. This review presents a systematic account of the proteases of Bacillus subtilis and their activities. It reviews the proteases found in, or associated with, the cytoplasm, the cell membrane, the cell wall and the external milieu. Where known, the impacts of the deletion of particular proteases are discussed, particularly in relation to industrial applications. [ABSTRACT FROM AUTHOR]

Research was conducted to examine a potential role of products of wprA in the integrity of secretory proteins during late stages in the secretion pathway. The potential of wprA mutants to increase the productivity of Bacillus subtilis for secretory proteins was also investigated. Results identified one role for the products of the B. subtilis wprA gene. Findings have important implications for the use of B. subtilis and other members of the genus as hosts for the secretion of native and nonnative Bacillus proteins.

A study was conducted to examine the yvsA-yvqA region of the Bacillus subtilis chromosome which supports genes associated with metal ion uptake and a putative sigma factor. DNA fragments were determined by random primed labeling using the Rediprime system while pUC18 clones were prepared by universal forward and reverse primers. Results indicated that the yvrC, yvrB, yvrA and yvqK genes were arranged in an operon of 3.9 kb in size encoding another putative transporter.

The functional roles of the Pho regulon PhoR and PhoP regulators of Bacillus subtilis on cell wall anionic polymers were analyzed to determine the mechanisms of teichuronic acid biosynthesis. Analysis of Bacillus subtilis PhoR and PhoP regulons indicated the role of the phosphate regulon for survival in extreme environments involving phosphate starvation. Furthermore, the induction of genes in the Pho regulon during phosphate starvation was regulated by a second unidentified phosphate-sensing mechanism.

The phosphate-starvation-inducible or Psi proteins of Bacillus subtilis (Bs)strain 168 was analyzed by two-dimensional gel electrophoresis. Analysis of Psi protein products from wild-type and phoR Bs mutants indicated the presence of two classes of proteins. Furthermore, the Class I Psi proteins are Pho regulons that exhibited PhoP/R-dependence while the class II PhoR-independent proteins are induced by glucose starvation.

The dnaB-pheA region of Bacillus subtilis chromosome encodes 113 open reading frames (ORFs) for 65 amino acids and putative polypeptides. The regions also contains new genes such as gerH, relA, phoT, spoVIA and pfk. The identified ORFs such as ysaA encodes a protein that is similar to the protein product of Escherichia coli yjG gene. The region also contains lytS, lytT, ysbA, ysbB, infC, rpml, rpiT, ysdC and abnA genes that exhibit regulatory activities related to primary metabolism and stress response.

Toxin synthesis by Shiga toxin-producing Escherichia coli (STEC) appears to be coregulated through induction of the integrated bacteriophage that encodes the toxin gene. Phage production is linked to induction of [...]

Explaining the so-called viable but non-culturable (VNC) state seen in some prokaryotic microorganisms by stating that cell destruction is a result of cell suicide by oxidative damage will only cloud the issue of the non-culturability of some microorganisms. The failure to culture microorganisms should not be explained by one single mechanism but by several causes. The absence of nutrient-rich media and growth stimulation are two of the more feasible explanations for the unculturability of some microorganisms.