RESUMO
A coccal-shaped organism, designated 516(T), was isolated from yan-tsai-shin (fermented broccoli stems), a traditional fermented food in Taiwan. 16S rRNA gene sequencing results showed that strain 516(T) had 98.9â% sequence similarity to that of the type strain Lactococcus garvieae NBRC 100934(T). Comparison of three housekeeping genes, rpoA, rpoB and pheS, revealed that strain 516(T) was well separated from Lactococcus garvieae NBRC 100934(T). DNA-DNA hybridization studies indicated that strain 516(T) had low DNA relatedness with Lactococcus garvieae NBRC 100934(T) (46.1â%). The DNA G+C content of strain 516(T) was 38.1 mol% and the major fatty acids were C16â:â0 (22.7â%), C19â:â0 cyclo ω8c (17.9â%) and summed feature 7 (29.0â%). Based on the evidence, strain 516(T) represents a novel species of the genus Lactococcus, for which the name Lactococcus formosensis sp. nov. is proposed. The type strain is 516(T) (â=âNBRC 109475(T)â=âBCRC 80576(T)).
Assuntos
Brassica/microbiologia , Fermentação , Microbiologia de Alimentos , Lactococcus/classificação , Filogenia , Técnicas de Tipagem Bacteriana , Composição de Bases , DNA Bacteriano/genética , Ácidos Graxos/química , Genes Bacterianos , Ácido Láctico/biossíntese , Lactococcus/genética , Lactococcus/isolamento & purificação , Dados de Sequência Molecular , Hibridização de Ácido Nucleico , Peptidoglicano/química , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , TaiwanRESUMO
Enterococcus sp. 812, isolated from fresh broccoli, was previously found to produce a bacteriocin active against a number of Gram-positive bacteria, including Listeria monocytogenes. Bacteriocin activity decreased slightly after autoclaving (121 °C for 15 min), but was inactivated by protease K. Mass spectrometry analysis revealed the bacteriocin mass to be approximately 4,521.34 Da. N-terminal amino acid sequencing yielded a partial sequence, NH2-ATYYGNGVYXDKKKXWVEWGQA, by Edman degradation, which contained the consensus class IIa bacteriocin motif YGNGV in the N-terminal region. The obtained partial sequence showed high homology with some enterococcal bacteriocins; however, no identical peptide or protein was found. This peptide was therefore considered to be a novel bacteriocin produced by Enterococcus sp. 812 and was termed enterocin T.
Assuntos
Bacteriocinas/isolamento & purificação , Bacteriocinas/metabolismo , Motivos de Aminoácidos , Sequência de Aminoácidos , Bacteriocinas/química , Enterococcus/química , Enterococcus/metabolismo , Bactérias Gram-Positivas , Alinhamento de SequênciaRESUMO
A coccal strain isolated from fresh broccoli was initially identified as Enterococcus saccharolyticus; however, molecular identification and phenotypic traits did not support this identification. DNA-DNA hybridization with the type strain of E. saccharolyticus (76.4â% relatedness), DNA G+C content (35.7 mol%), phylogenetic analysis based on 16S rRNA, pheS and rpoA gene sequences, rep-PCR fingerprinting and profiles of cellular fatty acids, whole-cell proteins and enzyme activities, together with carbohydrate metabolism characteristics, indicated that this strain is distinct and represents a novel subspecies, for which the name Enterococcus saccharolyticus subsp. taiwanensis subsp. nov. is proposed. The type strain is 812(T) (â=âNBRC 109476(T)â=âBCRC 80575(T)). Furthermore, we present an emended description of Enterococcus saccharolyticus and proposal of Enterococcus saccharolyticus subsp. saccharolyticus subsp. nov. (type strain ATCC 43076(T)â=âCCUG 27643(T)â=âCCUG 33311(T)â=âCIP 103246(T)â=âDSM 20726(T)â=âJCM 8734(T)â=âLMG 11427(T)â=âNBRC 100493(T)â=âNCIMB 702594(T)).