9 结果
A total of 17 bacterial isolates from northern elephant seals, tentatively classified within the family Pasteurellaceae, were further characterized by genotypic and phenotypic tests. Phylogenetic analysis of partial 16S rRNA and rpoB gene sequences showed that the isolates investigated formed a
Melibiose permease (MelB) of Escherichia coli is a secondary transporter that couples the uptake of melibiose and various other galactosides to symport of cations that can be Na+, Li+ or H+. MelB belongs to the glycoside-pentoside-hexuronide: cation symporter family of porters and is suggested to
From 133 saliva samples of humans we isolated 32 strains (24%) of Streptococcus sobrinus on an BYCSB selective medium. The very hard colonies of S. sobrinus on this medium were characterized by a distinct chalky white halo of water insoluble glucan ("glucan-halo") produced in large amounts from the
Isolates from a collection of phenotypically melibiose-negative (Mel-) Streptococcus mutans from widely-scattered geographical locations were examined and found to lack the activities of the enzymes alpha-galactosidase and alpha-glucosidase, in addition to being unable to transport melibiose. Cloned
The melibiose permease of Escherichia coli (MelB) catalyzes the coupled stoichiometric symport of a galactoside with a cation (either Na(+), Li(+), or H(+)), using free energy from the downhill translocation of one cosubstrate to catalyze the accumulation of the other. Here, we present a 3D
The diversity between Streptococcus mutans clinical isolates from 5-year-old children and their mothers in two South African ethnic groups was investigated. The gtfB gene encoding for glucosyltransferase (EC 2.4.1.5), an enzyme responsible for the synthesis of extracellular polysaccharides was
Alpha-galactosidases catalyze the hydrolysis of terminal alpha-1,6-galactosyl units from galacto-oligosaccharides and polymeric galactomannans. The crystal structures of tetrameric Saccharomyces cerevisiae alpha-galactosidase and its complexes with the substrates melibiose and raffinose have been
A new serotype (h) of Streptococcus mutans was isolated from the dental plaque of monkeys (Macaca fascicularis). Serotype h strains fermented mannitol and melibiose but not sorbitol or raffinose, failed to hydrolyse aesculin and arginine, did not produce hydrogen peroxide and were unable to grow in
Recognition of the carbohydrate part of cellular glycoconjugates by sugar receptors like lectins may contribute to biosignaling and interactions between normal and transformed cells. Such recognitions may be essential for establishing phenotypic characteristics in neoplastic cells, including