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The analysis of the bacterial microbiota of retain samples of pork salami revealed an isolate (strain TMW 1.2011T) that could neither be assigned to typical genera of starter organisms nor to any other known meat-associated species. Cells were Gram-stain-positive, short, straight rods occurring singly, in pairs or short chains. Phylogenetic analysis of the 16S rRNA gene sequence and specific phenotypic characteristics showed that strain TMW 1.2011T belonged to the phylogenetic Lactobacillus alimentarius group, and the closest neighbours were Lactobacillus nodensis JCM 14932T (97.8 % 16S rRNA gene sequence similarity), Lactobacillus tucceti DSM 20183T (97.4 %), 'Lactobacillus ginsenosidimutans' EMML 3041 (97.3 %), Lactobacillus versmoldensis DSM 14857T (96.9 %) and Lactobacillus furfuricola JCM 18764T (97.2 %). Similarities using partial gene sequences of the alternative chronometers pheS, dnaK and rpoA also support these relationships. DNA-DNA relatedness between the novel isolate and L. nodensis JCM 14932T, L. versmoldensis DSM 14857T and L. tucceti DSM 20183T, L. furfuricola JCM 18764T and 'L. ginsenosidimutans' EMML 3041 were below 70 % and the DNA G+C content was 36.3 mol%. The cell-wall peptidoglycan type is l-Lys-Gly-d-Asp. Based on phylogenetic, chemotaxonomic and physiological evidence, strain TMW 1.2011T represents a novel species of the genus Lactobacillus, for which the name Lactobacillus insicii sp. nov. is proposed. The type strain is TMW 1.2011T ( = CECT 8802T = DSM 29801T).

Lactobacillus versmoldensis sp. nov. (KU-3T) was isolated from raw fermented sausages. The new species was present in high numbers, and frequently dominated the lactic acid bacteria (LAB) populations of the products. 16S rDNA sequence data revealed that the isolates are closely related to the species Lactobacillus kimchii DSM 13961T, Lactobacillus paralimentarius DSM 13238T, Lactobacillus alimentarius DSM 20249T and Lactobacillus farciminis DSM 20184T. DNA-DNA reassociation data, however, clearly distinguished the new isolates from these species; they showed a low degree of DNA relatedness with the type strains of this group of phylogenetically closely related lactobacilli. These results warrant separate species status for strain KU-3T, for which the name Lactobacillus versmoldensis sp. nov. is proposed. The type strain is KU-3T (=DSM 14857T =NCCB 100034T =ATCC BAA-478T).

Sakacin P is a small, heat-stable, ribosomally synthesized peptide produced by certain strains of Lactobacillus sake. It inhibits the growth of several Gram-positive bacteria, including Listeria monocytogenes. A 7.6 kb chromosomal DNA fragment from Lb. sake Lb674 encompassing all genes responsible for sakacin P production and immunity was sequenced and introduced into Lb. sake strains Lb790 and Lb706X which are bacteriocin-negative and sensitive to sakacin P. The transformants produced sakacin P in comparable amounts to the parental strain, Lb674. The sakacin P gene cluster comprised six consecutive genes: sppK, sppR, sppA, spiA, sppT and sppE, all transcribed in the same direction. The deduced proteins SppK and SppR resembled the histidine kinase and response regulator proteins of bacterial two-component signal transducing systems of the AgrB/AgrA-type. The genes sppA and spiA encoded the sakacin P preprotein and the putative immunity protein, respectively. The predicted proteins SppT and SppE showed strong similarities to the proposed transport proteins of several other bacteriocins and to proteins implicated in the signal-sequence-independent export of Escherichia coli haemolysin A. Deletion and frameshift mutation analyses showed that sppK, sppT and sppE were essential for sakacin P production in Lb706X. The putative SpiA peptide was shown to be involved in immunity to sakacin P. Analogues of sppR and spiA were found on the chromosomes of Lb. sake Lb706X and Lb790, indicating the presence of an incomplete spp gene cluster in these strains.

Sakacin 674, a bacteriocin produced by Lactobacillus sake Lb764 and which inhibits the growth of Listeria monocytogenes, was purified to homogeneity by ammonium sulphate precipitation and sequential ion exchange, hydrophobic interaction and reversed phase chromatography. The complete amino acid sequence of sakacin 674 was determined by Edman degradation. The bacteriocin consisted of 43 amino acid residues and had a calculated molecular mass of 4436.6 Da, which is in good agreement with the molecular mass of 4437.2 as determined by mass spectrometry. The structural gene encoding sakacin 674 (sakR) was located on the chromosome. This gene was cloned and sequenced. It encoded a primary translation product of 61 amino acid residues which was cleaved between amino acids 18 and 19 to yield the active sakacin 674. Sakacin 674 resembled other known bacteriocins and was very similar to sakacin P.