We describe the identification and characterization of a gene, herein designated cotG, encoding an abundant coat protein from the spores of Bacillus subtilis. The cotG open reading frame is 195 codons in length and is capable of encoding a polypeptide of 24 kDa that contains nine tandem copies of the 13-amino-acid long, approximately repeated sequence H/Y-K-K-S-Y-R/C-S/T-H/Y-K-K-S-R-S.cotG is located at 300؇ on the genetic map close to another coat protein gene, cotB. The cotG and cotB genes are in divergent orientation and are separated by 1.3 kb. Like the promoter for cotB, the cotG promoter is induced at a late stage of sporulation under the control of the RNA polymerase sigma factor K and the DNA-binding protein GerE. The ؊10 and ؊35 nucleotide sequences of the cotG promoter resemble those of other promoters recognized by K -containing RNA polymerase, and centered 70 bp upstream of the apparent start site is a sequence that matches the consensus binding site for GerE. Spore coat proteins from a newly constructed cotG null mutant lack not only CotG but also CotB, a finding that suggests that CotG may be a morphogenetic protein that is required for the incorporation of CotB into the coat.Spores of the gram-positive bacterium Bacillus subtilis are encased in a complex protein shell known as the coat consisting of 15 or more different proteins. So far, genes for 10 of these coat proteins have been identified. These are located at diverse positions on the chromosome and encode polypeptides of 65 (CotA), 59 (CotB), 10 (CotC), 9 (CotD), 24 (CotE), 19 (CotF), 10 (CotT), 19 (CotX), 26 (CotY), and 18 (CotZ) kDa (2,4,7,29,31). In the cases of CotF and CotT, little of the full-length gene products is found in the coat. Rather, CotF is present as two proteolytic fragments of 8 and 5 kDa, and CotT is present as a proteolytic fragment of 8 kDa (2, 4). Coat proteins are organized in two principal layers, a lamellar inner coat and an electron-dense outer coat (1), with certain proteins, such as CotD, being present in the inner coat, and other proteins, such as CotA, CotB, and CotC, being present in the outer coat (31). The coat is assembled at intermediate to late stages of sporulation when the nascent spore (known as the forespore) is present as a free protoplast, wholly engulfed within the mother cell compartment of the developing sporangium. Coat proteins are recruited to the outer surface of the membrane surrounding the forespore by the sporulation protein SpoIVA (which has not been detected in mature spores and hence is not referred to as a coat protein) (8,19,21). Morphogenetic events under the control of SpoIVA lead to the assembly of a ring of CotE protein around the forespore (8). The CotE ring is separated from the outer surface of the forespore (where SpoIVA is located) by a small gap, which is believed to be the site at which the inner coat will be assembled. Meanwhile, CotE dictates the assembly of the proteins of the outer coat, where it is itself located (8, 31). The production of coat proteins is governed by ...

The pyruvate oxidase gene (poxB) from Lactobacillus plantarum Lp80 was cloned and characterized. Northern blot and primer extension analyses revealed that transcription of poxB is monocistronic and under the control of a vegetative promoter. poxB mRNA expression was strongly induced by aeration and was repressed by glucose. Moreover, Northern blotting performed at different stages of growth showed that poxB expression is maximal in the early stationary phase when glucose is exhausted. Primer extension and in vivo footprint analyses revealed that glucose repression of poxB is mediated by CcpA binding to the cre site identified in the promoter region. The functional role of the PoxB enzyme was studied by using gene overexpression and knockout in order to evaluate its implications for acetate production. Constitutive overproduction of PoxB in L. plantarum revealed the predominant role of pyruvate oxidase in the control of acetate production under aerobic conditions. The ⌬poxB mutant strain exhibited a moderate (20 to 25%) decrease in acetate production when it was grown on glucose as the carbon source, and residual pyruvate oxidase activity that was between 20 and 85% of the wild-type activity was observed with glucose limitation (0.2% glucose). In contrast, when the organism was grown on maltose, the poxB mutation resulted in a large (60 to 80%) decrease in acetate production. In agreement with the latter observation, the level of residual pyruvate oxidase activity with maltose limitation (0.2% maltose) was less than 10% of the wild-type level of activity.

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Background: Lactic acid bacteria of the genus Lactobacillus and Bifidobacterium are one of the most important health promoting groups of the human intestinal microbiota. Their protective role within the gut consists in out competing invading pathogens for ecological niches and metabolic substrates. Among the features necessary to provide health benefits, commensal microorganisms must have the ability to adhere to human intestinal cells and consequently to colonize the gut. Studies on mechanisms mediating adhesion of lactobacilli to human intestinal cells showed that factors involved in the interaction vary mostly among different species and strains, mainly regarding interaction between bacterial adhesins and extracellular matrix or mucus proteins. We have investigated the adhesive properties of Lactobacillus plantarum, a member of the human microbiota of healthy individuals.

We tested for the presence of coronary calcifications in patients with chronic renal disease not on dialysis and studied its progression in 181 consecutive non-dialyzed patients who were followed for a median of 745 days. Coronary calcifications (calcium score) were tallied in Agatston units by computed tomography, and the patients were stratified into two groups by their baseline calcium score (100 U or less and over 100 U). Survival was measured by baseline calcium score and its progression. Cardiac death and myocardial infarction occurred in 29 patients and were significantly more frequent in those patients with calcium scores over 100 U (hazard ratio of 4.11). With a calcium score of 100 U or less, the hazard ratio for cardiac events was 0.41 and 3.26 in patients with absent and accelerated progression, respectively. Thus, in non-dialyzed patients, the extent of coronary calcifications was associated to cardiac events, and progression was an independent predictive factor of cardiac events mainly in less calcified patients. Hence, assessment of coronary calcifications and progression might be useful for earlier management of risk factors and guiding decisions for prevention of cardiac events in this patient population.