Lactobacillus kunkeei is an inhabitant of fructose-rich niches and is a potential member of the fructophilic lactic acid bacteria. In the present study, the phylogenetic and biochemical characteristics of the type strain and eight isolates of L. kunkeei, originating from wine, flowers and honey, were studied. The nine isolates, including the type strain, formed a well-defined phylogenetic subcluster based on the analysis of 16S rRNA gene sequences. The subcluster was not closely related to other subclusters in the Lactobacillus phylogenetic group. Biochemically, the eight new isolates showed typical fructophilic characteristics. The eight isolates grew poorly on glucose, but grew well on fructose. Good growth on glucose was only recorded in the presence of electron acceptors. The type strain of L. kunkeei differed from the other isolates only on the basis of poor growth on fructose. Although they belong to a group of obligately heterofermentative lactic acid bacteria, all nine isolates, including the type strain, produced almost equimolar amounts of lactic acid and acetic acid and very little ethanol from glucose. Eight of the isolates can thus be regarded as typical 'obligately' fructophilic lactic acid bacteria. Although the type strain of L. kunkeei was phenotypically slightly different from the other isolates, it possessed several important fructophilic characteristics. On the basis of the evidence gathered in this study, the type strain of L. kunkeei is recognized as a member of the 'obligately' fructophilic lactic acid bacteria.

A fructophilic lactic acid bacterium, designated strain F214-1 T , was isolated from a flower of Tropaeolum majus in South Africa. Based on phylogenetic analysis of 16S rRNA gene sequences, the strain formed a subcluster with Fructobacillus ficulneus and Fructobacillus pseudoficulneus and, based on recA gene sequences, the strain formed a subcluster with F. ficulneus. DNA-DNA hybridization studies showed that strain F214-1 T was phylogenetically distinct from its closest relatives. Acid was produced from the fermentation of D-glucose, D-fructose and D-mannitol only. D-Fructose was the preferred sole carbon and energy source and was fermented more rapidly than D-glucose. Growth of the strain on D-glucose under anaerobic conditions was very weak but external electron acceptors such as oxygen and pyruvate enhanced growth on D-glucose. Lactic acid and acetic acid were produced from D-glucose in equimolar amounts. Ethanol was produced at very low levels, despite the strain's obligately heterofermentative metabolism. Based on these data, strain F214-1 T represents a novel species of fructophilic bacteria in the genus Fructobacillus, for which the name Fructobacillus tropaeoli sp. nov. is proposed. and sodium azide (0.05; pH 6.8), was added to the crushed samples and the bags were incubated at 30 u C for 24 h. After incubation, each sample was inoculated into FYP broth by using a loop and incubated at 30 u C under aerobic conditions on an orbital shaker (120 r.p.m.) for 2 days. The culture was then streaked onto FYP agar plates containing (l 21) 5 g CaCO 3 and 12 g agar. The plates were incubated at 30 u C under aerobic conditions until visible colonies were observed. Colonies were selected based on differences in morphology, such as colony size and shape, and the clearance zone formed from hydrolysis of CaCO 3 by lactic acid, inoculated into FYP broth and GYP broth and incubated statically for 24 h at 30 u C. GYP broth differed from FYP broth by containing 10 g l 21 D-glucose instead of D-fructose.Strain F214-1 T grew well in FYP broth but poorly in GYP broth and was, therefore, regarded as a fructophilic lactic acid bacterium. The strain was stored at 280 u C in nutrient broth containing 20 % (v/v) glycerol. Strains F. durionis LMG 22556 T , F. ficulneus JCM 12225 T , F. fructosus NRIC 1058T and F. pseudoficulneus DSM 14568 T were cultured in FYP broth and used as reference strains.The 16S rRNA gene sequence of strain F214-1 T was determined as described previously (Endo & Okada, 2005). The closest recognized relatives of the isolate were determined by performing database searches and sequences of closely related species were retrieved from DDBJ. Multiple sequence alignments were carried out by using CLUSTAL_X, version 1.18 (Thompson et al., 1997). Distance matrices for the aligned sequences were calculated by using the two-parameter method of Kimura (1980) and phylogenetic trees were reconstructed by using the neighbourjoining, maximum-likelihood and maximum-parsimony methods in PHYLIP version 3.65 software as descr...

The contents, components, and synthesis genes of cell wall teichoic acid (WTA) in 18 strains of Lactobacillus plantarum were compared. The WTA of each strain was classified by its components as being either the glycerol- or the ribitol-type. The different strains in the WTA type showed marked differences also in two gene regions, tagD1-tagF2 and lp_1816-tagB2, as for the presence or absence, nucleotide sequences, and transcriptional activities. Our results clearly showed that the tagD1-tagF2 and lp_1816-tagB2 regions contained the synthesis genes of the WTA backbone of L. plantarum. We verified that the genes in the tagD1-tagF2 region were involved in the synthesis of the glycerol-type backbone. Furthermore, we propose that the genes in the lp_1816-tagB2 region were tarI, tarJ, tarK, and tarL, which are involved in the synthesis of the ribitol-type backbone.

Lactobacillus is the largest genus within the lactic acid bacteria (LAB), with almost 180 species currently identified. Motility has been reported for at least 13 Lactobacillus species, all belonging to the Lactobacillus salivarius clade. Motility in lactobacilli is poorly characterized. It probably confers competitive advantages, such as superior nutrient acquisition and niche colonization, but it could also play an important role in innate immune system activation through flagellin-Toll-like receptor 5 (TLR5) interaction. We now report strong evidence of motility in a species outside the L. salivarius clade, Lactobacillus curvatus (strain NRIC 0822). The motility of L. curvatus NRIC 0822 was revealed by phase-contrast microscopy and soft-agar motility assays. Strain NRIC 0822 was motile at temperatures between 15°C and 37°C, with a range of different carbohydrates, and under varying atmospheric conditions. We sequenced the L. curvatus NRIC 0822 genome, which revealed that the motility genes are organized in a single operon and that the products are very similar (>98.5% amino acid similarity over >11,000 amino acids) to those encoded by the motility operon of Lactobacillus acidipiscis KCTC 13900 (shown for the first time to be motile also). Moreover, the presence of a large number of mobile genetic elements within and flanking the motility operon of L. curvatus suggests recent horizontal transfer between members of two distinct Lactobacillus clades: L. acidipiscis in the L. salivarius clade and L. curvatus in the L. sakei clade. This study provides novel phenotypic, genetic, and phylogenetic insights into flagellum-mediated motility in lactobacilli.M otility in bacterial species is often mediated by a sophisticated molecular structure called the flagellum. This chief organelle of bacterial motility is self-assembled using dozens of different proteins and rotates to propel the cell forward (1). The filament of the bacterial flagellum is composed of one or more flagellin proteins, a microbe-associated molecular pattern (MAMP) which is recognized by the host Toll-like receptor 5 (TLR5) (2) and which, via activation of the nuclear factor kappa B (NF-B) signaling pathway, engages defense responses both systemically and at epithelial surfaces (3). Several flagellate bacterial pathogens (alphaproteobacteria and epsilonproteobacteria) have evolved flagellin proteins with sequence changes that avoid TLR5 recognition while maintaining motility (4). In an ecosystem, flagellum-mediated motility may confer a competitive advantage on motile species over nonmotile species with respect to niche colonization, biofilm formation, and the secretion of virulence proteins by pathogenic bacteria (5).Lactobacillus spp. constitute a very diverse group and the largest genus within the lactic acid bacteria (LAB). Lactobacilli are associated mainly with food production and probiotics (6). Some Lactobacillus species colonize the gastrointestinal, oral, and genital tracts of humans, making them important members of the human microbiota (7)....

Background: Most lactic acid bacteria are non-motile but some of them are flagellated and exhibit motility. So far, motile lactobacilli have rarely been studied, and characteristics of their flagellins are poorly understood. In this study, a highly motile strain of Lactobacillus agilis was recruited for transcriptional analysis and characterization of its flagellins. Results: Unlike another motile lactic acid bacteria of intestinal isolate, Lactobacillus ruminis, flagellar filaments of the L. agilis strain probably consist of two homologous but distinct flagellins. Glycosylation of the flagellar filaments and their resistance to heat, acid and SDS were also observed. The immunological activity of the flagellins was evaluated through the stimulation of Caco-2 cells. The results show that TLR5-stimulating activity of the protein is attenuated, likely due to an incomplete TLR5-recognition site.