A taxonomic study was conducted on two Gram-reaction-positive, catalase-negative, irregular short-rod-shaped or coccoid lactic acid bacteria, designated strains SG25T and SG23, that were isolated ...from grains of fermented Japanese rice (Oryza sativa L. subsp. japonica). A phylogenetic analysis based on 16S rRNA gene sequence data clearly showed that the strains belonged to the genus Weissella and were most closely related to Weissella soli LMG 20113T (with a sequence similarity of 96.9 % for each novel strain). The peptidoglycan of each strain contained the amino acids glutamic acid, lysine, serine and alanine in a molar ratio of 1.0 : 1.2 : 0.5 : 3.0, respectively. On the basis of the unusual phenotypic characteristics of the novel strains and the low levels of DNA–DNA relatedness recorded between each novel strain and Weissella soli JCM 12536T, strains SG25T and SG23 represent a single novel species in the genus Weissella, for which the name Weissella oryzae sp. nov. is proposed. The type strain is SG25T ( = JCM 18191T = DSM 25784T).
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.
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.
The flagella filaments of L. agilis BKN88 consist of two homologous glycosylated flagellins, which likely have an incomplete TLR5-recognition site. The characteristics of the flagellin are presumably a consequence of adaptation as a commensal microbe in the gastrointestinal tract.
Three Gram-stain positive, non-motile, non-spore-forming, catalase-negative and rod-shaped bacterial strains (IWT5T, IWT25T and IWT140), isolated from silage, were investigated by using a polyphasic ...taxonomic approach. Strains IWT5T and IWT25T grew at 10-37 °C and 30-37 °C, and at pH 4.0-7.5 and 4.0-7.0, respectively. The G+C contents of genomic DNA of strains IWT5T and IWT25T were 43.2 and 44.4 mol%, respectively. Strains IWT5T and IWT25T contained C16 : 0, C18 : 1 ω9c and summed feature 7 (unknown 18.846/C19 : 1 ω6c/C19 : 0cyclo ω10c) as the major fatty acids. Strain IWT5T was most closely related to the type strains of Lactobacillus mixtipabuli (99.9 % 16S rRNA gene sequence similarity) and Lactobacillus silagei (99.5 %). For IWT25T, the 16S rRNA gene sequence similarities with the closely related neighbour type strains L. mixtipabuli and L. silagei were 99.5 and 99.5 %, respectively. The 16S rRNA gene sequence similarities among the three novel isolates were 99.5-99.9 %. The average nucleotide identities of strains IWT5T and IWT25T to other neighbours of the genus Lactobacillus were less than 82 % and the genomes of IWT25T and IWT140 shared 97.3 % average nucleotide identity, demonstrating that the three strains were allocated to two different novel species of the genus Lactobacillus. Together with multilocus sequence analysis, phenotypic and chemotaxonomic characteristics, strains IWT5T (=JCM 31144T=DSM 102973T) and IWT25T (=JCM 31145T=DSM 102974T) are proposed as the type strains of novel species of the genus Lactobacillus, with the names Lactobacillus silagincola sp. nov. and Lactobacillus pentosiphilus sp. nov., respectively.
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 NRIC0822). 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 inthe L. sakei clade. This study provides novel phenotypic, genetic, and phylogenetic insights into flagellum-mediated motility in lactobacilli.
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. The type strain is F214-1(T) ( = JCM 16675(T) = DSM 23246(T)).
Two strains of lactic acid bacteria, Nu27T and Nu29, were isolated from Nukadoko, rice bran paste for Japanese pickles. The isolates were Gram-stain-positive, rod-shaped, catalase-negative, ...non-motile and facultatively anaerobic lactic acid bacteria. The isolates showed identical 16S rRNA gene sequences. The closest relatives to strain Nu27T based on 16S rRNA gene sequence similarities were Lactobacillus versmoldensis KU-3T (98.9 % 16S rRNA gene sequence similarity), Lactobacillus nodensis iz4bT (96.3 %) and Lactobacillus tucceti CECT 5290T (97.2 %). DNA–DNA relatedness values revealed genotype separation of the two isolates from the above three species. Based on the physiological, biochemical and genotypic characteristics provided, the isolates represent a novel species of the genus Lactobacillus, for which name is Lactobacillus furfuricola proposed. The type strain is Nu 27T ( = JCM 18764T = NRIC 0900T = DSM 27174T).
A Gram-reaction-positive, facultatively anaerobic, non-spore-forming and catalase-negative rod-shaped bacterial strain, designated IWT126(T), was isolated from orchardgrass (Dactylis glomerata L.) ...silage preserved in Hachimantai, Iwate, Japan. The isolate showed growth at 15-45 °C, pH 3.5-7.5 and with 4.0 % (w/v) NaCl. The cell wall peptidoglycan did not contain meso-diaminopimelic acid, and the DNA G+C content was 45.6 mol%. The major cellular fatty acids were C16 : 0 and C19 : 1 cyclo 9,10. Based on 16S rRNA gene sequence similarity, strain IWT126(T) was classified as a member of the genus Lactobacillus and was most closely related to Lactobacillus odoratitofui YIT 11304(T) (98.7 %), Lactobacillus similis JCM 2765(T) (98.5 %), Lactobacillus collinoides JCM 1123(T) (97.6 %), Lactobacillus paracollinoides DSM 15502(T) (97.6 %) and Lactobacillus kimchicus DCY51(T) (96.9 %). Based on sequence analysis of the phenylalanyl-tRNA synthase α-subunit (pheS) gene, strain IWT126(T) was well separated from its phylogenetic neighbours in the genus Lactobacillus. Based on physiological, biochemical and genotypic results, as well as low DNA-DNA relatedness to recognized phylogenetic relatives in the genus Lactobacillus, classification of strain IWT126(T) as a representive of a novel species named Lactobacillus silagei sp. nov. is proposed. The type strain is IWT126(T) ( = JCM 19001(T) = DSM 27022(T)).
Dry aging (DA) allows for the storage of meat without packaging at 0 to 3°C for several weeks. It enhances the production of pleasant flavors, tenderness, and juiciness in meat. Due to the long ...storage period and roles of indigenous microbiota in the maturation of several meat products, the microbiota of DA meat is of interest in terms of microbial contributions and food hygiene but has not yet been characterized in detail. This study identified the microbiota of pork loins during DA using culturing and culture‐independent meta‐16S rRNA gene sequencing and elucidated its characteristics. The amounts of free amino acids and profiles of aroma‐active compounds were also monitored by high‐performance liquid chromatography and gas chromatography, respectively. The meta‐16S rRNA gene sequencing revealed that Pseudomonas spp. generally dominated the microbiota throughout DA; however, the culturing analysis showed marked changes in the species composition during DA. Acinetobacter spp. were the second most dominant bacteria before DA in the culture‐independent analysis but became a minor population during DA. The cell numbers of yeasts showed an increased tendency during DA, and Debaryomyces hansenii was the only microorganism isolated from all meat samples throughout DA. Well‐known foodborne pathogens were not observed in two microbiota analyses. The amounts of free amino acids were increased by DA, and the number of aroma‐active compounds and their flavor dilution values markedly changed during DA. Most microbial isolates showed positive reactions with proteolytic and lipolytic activities, suggesting their contribution to tenderness and aroma production in DA meats.
Microbiota on pork surface considerably changed during dry aging. Most microbial isolates showed positive reactions with proteolytic and lipolytic activities. The amounts of free amino acids were increased, and the number of aroma‐active compounds and their flavor dilution values markedly changed during this process.
Lysozyme (LZ), a bacteriolytic enzyme, is found in the egg white of many avian eggs and plays an important role in host defense; however, LZ activity in emu (
Dromaius novaehollandiae) egg white is ...exceptionally undetectable. We cloned and characterized emu goose-type LZ (LZG) and chicken-type LZ (LZC) genes. RT-PCR analysis revealed very low LZG gene expression levels and absence of LZC gene expression in the emu oviduct. Sequencing of full-length LZG and LZC cDNAs indicated that their amino acid sequences show high similarities to ostrich LZG and LZC, respectively, with conserved catalytic residues for enzymatic activities. Whereas recombinant emu LZG prepared using
Pichia pastoris exhibited similar enzyme activity as ostrich LZG, recombinant emu LZC exhibited significantly higher lytic activity than chicken LZC. We concluded that emus have functional genes for both LZG and LZC like many other avians, and the LZG gene is expressed in oviduct probably as in other ratite, however, its expression levels in egg white were low to be detected.
► Lysozyme was substantially undetectable in emu egg white. ► Emu had goose- and chicken-type lysozyme genes. ► The sequences showed high similarity to those of ostrich and chicken lysozymes. ► Gene expression for goose-type lysozyme was very low level in emu oviduct. ► Enzyme activities of recombinant lysozymes proved those genes are functional.
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