A plasmid-linked antimicrobial peptide, named coagulin, produced by Bacillus coagulans I ₄ has recently been reported (B. Hyronimus, C. Le Marrec and M. C. Urdaci, J. Appl. Microbiol. 85:42–50, 1998). In the present study, the complete, unambiguous primary amino acid sequence of the peptide was obtained by a combination of both N-terminal sequencing of purified peptide and the complete sequence deduced from the structural gene harbored by plasmid I ₄ . Data revealed that this peptide of 44 residues has an amino acid sequence similar to that described for pediocins AcH and PA-1, produced by different Pediococcus acidilactici strains and 100% identical. Coagulin and pediocin differed only by a single amino acid at their C terminus. Analysis of the genetic determinants revealed the presence, on the pI ₄ DNA, of the entire 3.5-kb operon of four genes described for pediocin AcH and PA-1 production. No extended homology was observed between pSMB74 from P. acidilactici and pI ₄ when analyzing the regions upstream and downstream of the operon. An oppositely oriented gene immediately dowstream of the bacteriocin operon specifies a 474-amino-acid protein which shows homology to Mob-Pre (plasmid recombination enzyme) proteins encoded by several small plasmids extracted from gram-positive bacteria. This is the first report of a pediocin-like peptide appearing naturally in a non-lactic acid bacterium genus.

A protease-sensitive antibacterial substance produced by Bacillus coagulans I4 strain, isolated from cattle faeces, was classified as a bacteriocin-like inhibitory substance and named coagulin. The i...

The complete nucleotide sequence of øO1205, a temperate bacteriophage infecting Streptococcus thermophilus strain CNRZ1205, was determined. The phage genome has a unit length of 43075 bp and appears to be packaged by the so-called headful mechanism. The genomic organization and structure of øO1205 resemble those of several temperate lactococcal phages that display a life-cycle-specific organization, where ORFs believed to be involved in the lysogenic life-cycle are clustered and arranged in an orientation opposite to the ORFs supposedly involved in the lytic life-cycle. Database searches revealed putative functions for several identified ORFs and further indicated that øO1205 is genetically related to a particular group of lactococcal phages. Three genes encoding the major structural proteins were identified on the øO1205 genome. The phage attachment site attP, the bacterial attachment site attB, and the two phage/chromosome junctions attL and attR were identified and found to contain a 40 bp common core sequence.

“Ropiness” is a bacterial alteration in wines, beers, and ciders, caused by β-glucan-synthesizing pediococci. A single glucosyltransferase, Gtf, controls ropy polysaccharide synthesis. In this study, we show that the correspondinggtfgene is also present on the chromosomes of several strains ofOenococcus oeniisolated from nonropy wines.gtfis surrounded by mobile elements that may be implicated in its integration into the chromosome ofO. oeni. gtfis expressed in all thegtf⁺strains, and β-glucan is detected in the majority of these strains. Part of this β-glucan accumulates around the cells forming a capsule, while the other part is liberated into the medium together with heteropolysaccharides. Most of the time, this polymer excretion does not lead to ropiness in a model medium. In addition, we show that wild or recombinant bacterial strains harboring a functionalgtfgene (gtf⁺) are more resistant to several stresses occurring in wine (alcohol, pH, and SO₂) and exhibit increased adhesion capacities compared to theirgtfmutant variants.

Natural-abundance ¹³ C-nuclear magnetic resonance was used to probe the intracellular organic solute content of the moderately halophilic bacterium Tetragenococcus halophila . When grown in complex growth media supplemented or not with NaCl, T. halophila accumulates glycine betaine and carnitine. Unlike other moderate halophiles, T. halophila was not able to produce potent osmoprotectants (such as ectoines and glycine betaine) through de novo synthesis when cultured in defined medium under hyperosmotic constraint. Addition of 2 mM carnitine, glycine betaine, or choline to defined medium improved growth parameters, not only at high salinity (up to 2.5 M NaCl) but also in media lacking NaCl. These compounds were taken up when available in the surrounding medium. The transport activity occurred at low and high salinities and seems to be constitutive. Glycine betaine and carnitine were accumulated by T. halophila in an unmodified form, while exogenously provided choline led to an intracellular accumulation of glycine betaine. This is the first evidence of the existence of a choline-glycine betaine pathway in a lactic acid bacterium. An assay showed that the compatible solutes strikingly repressed the accumulation of glutamate and slightly increased the intracellular potassium level only at high salinity. Interestingly, osmoprotectant-treated cells were able to maintain the intracellular sodium concentration at a relatively constant level (200 to 300 nmol/mg [dry weight]), independent of the NaCl concentration of the medium. In contrast, in the absence of osmoprotectant, the intracellular sodium content increased sharply from 200 to 2,060 nmol/mg (dry weight) when the salinity of the medium was raised from 1 to 2 M. Indeed, the imported compatible solutes play an actual role in regulating the intracellular Na ⁺ content and confer a much higher salt tolerance to T. halophila.