Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.2.1.23 (beta-galactosidase)
 14,648 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

One hundred and fifty human vaginal samples containing a diversity of pathogens or nonpathogens (Gardnerella vaginalis, Streptococcus sp., Staphylococcus sp., Candida albicans. Mycoplasma sp.) were examined for their content in lactobacilli of the Lactobacillus acidophilus complex. Although all samples contained lactobacilli, strains of the L. acidophilus complex were present in only twenty-nine cases. Isolates were further characterized and compared with type strains or reference strains in an attempt to differentiate by phenotypic means the genospecies of the L. acidophilus complex. Data regarding specific activities of beta-galactosidase (beta-gal) and of phospho-beta-galactosidase (P-beta-gal) provided no specific information at the species level within the L. acidophilus complex. DNA-relatedness differentiates this genospecies. Most lactobacilli isolated from the vaginal flora of symptomatic women were genotypically close to L. gasseri CIP 102991T by the technique of DNA/DNA hybridization.
 ...
PMID:Composition of the Lactobacillus acidophilus complex isolated from vaginal flora. 872 8

Phospho-beta-galactosidase (P-beta-gal; EC 3.2.1.85) is induced during growth of Leptotrichia buccalis ATCC 14201 on lactose and lactulose. The enzyme has been purified to electrophoretic homogeneity (M(r) approximately 53 kDa, pI approximately 4.8), and kinetic parameters have been determined using the chromogenic analog o-nitrophenyl-beta-D-galactopyranoside-6-phosphate as substrate. Both ATP and galactose-6-phosphate are inhibitors of P-beta-gal activity. Microsequence analysis has identified the first 32 residues from the N-terminus of the protein, and by comparative sequence alignment the enzyme can be assigned to Family 1 of the glycosylhydrolase superfamily. Polyclonal antibody against the enzyme permits the highly specific immuno-detection of P-beta-gal in cell-free extracts of L. buccalis. Although described previously in several Gram-positive species, this is the first reported purification of P-beta-gal from a Gram-negative organism.
 ...
PMID:Purification and some properties of phospho-beta-galactosidase from the Gram-negative oral bacterium Leptotrichia buccalis ATCC 14201. 1235 Dec 28

The nisA promoter is positively regulated in Lactococcus lactis ATCC 11454 by autoinduction via a two-component NisRK-mediated system. However, induction of this promoter can also occur when introduced into the plasmid-free L. lactis LM0230 during growth in galactose or lactose, independent of the NisRK system. In this study, we also characterized this galactose-mediated induction by determining the nisA start site during growth in galactose, which was identical to the nisA start site upon nisin induction. The region involved in the galactose-mediated induction of the nisA promoter was investigated by directed deletion analysis of a 200 bp region upstream of the nisA promoter in the transcription fusion pDOC99. The induction of the deletion derivatives by galactose and nisin was compared phenotypically using beta-galactosidase measurements, and the regions necessary for the induction were determined by sequence analysis. Analysis of these regions revealed two sets of a TCT direct repeat [TCT-N8-TCT] present at positions (-107 to -94) and (-39 to -26) relative to the transcription initiation site. Disruption of the upstream repeat abolished galactose induction and significantly reduced the nisin induction capacity, suggesting a potential pivotal role for these repeats in transcription induction of the nisA promoter. It was also observed that the galactose-mediated induction was abolished when a plasmid containing the phosphotransferase system (PTS), phospho-beta-galactosidase and tagatose pathway genes was introduced into this strain. As this effectively made the Leloir pathway redundant, it points to some component of this pathway as the specific inducer of the nisA promoter.
 ...
PMID:Characterization of the promoter regions involved in galactose- and nisin-mediated induction of the nisA gene in Lactococcus lactis ATCC 11454. 1240 22

In this study, we present a glimpse of the diversity of Lactococcus lactis subsp. lactis IL1403 beta-galactosidase phenotype-negative mutants isolated by negative selection on solid media containing cellobiose or lactose and X-Gal (5-bromo-4-chloro-3-indolyl-beta-d-galactopyranoside), and we identify several genes essential for lactose assimilation. Among these are ccpA (encoding catabolite control protein A), bglS (encoding phospho-beta-glucosidase), and several genes from the Leloir pathway gene cluster encoding proteins presumably essential for lactose metabolism. The functions of these genes were demonstrated by their disruption and testing of the growth of resultant mutants in lactose-containing media. By examining the ccpA and bglS mutants for phospho-beta-galactosidase activity, we showed that expression of bglS is not under strong control of CcpA. Moreover, this analysis revealed that although BglS is homologous to a putative phospho-beta-glucosidase, it also exhibits phospho-beta-galactosidase activity and is the major enzyme in L. lactis IL1403 involved in lactose hydrolysis.
 ...
PMID:Alternative lactose catabolic pathway in Lactococcus lactis IL1403. 1620 22

A number of species of lactobacilli were examined for their ability to ferment both the glucose and galactose moieties of lactose. Lactobacillus helveticus strains metabolized both the glucose and galactose moieties, whereas L. bulgaricus, L. lactis, and L. acidophilus strains metabolized only the glucose moiety and released galactose into the growth medium. All four species tested contained beta-galactosidase activity, and no significant phospho-beta-galactosidase activity was observed. L. bulgaricus and L. helveticus had a phosphoenolpyruvate (PEP):glucose phosphotransferase system for the uptake of glucose, but no evidence for a PEP:lactose phosphotransferase or PEP:galactose phosphotransferase system was obtained.
 ...
PMID:Transport and metabolism of lactose, glucose, and galactose in homofermentative lactobacilli. 1634 41

A simple and rapid method was developed to detect beta-galactosidase by using alpha- or beta-naphthyl-beta-d-galactopyranoside as substrate and fast garnet GBC as a dye coupler following polyacrylamide gel electrophoresis. This method was specific for beta-galactosidase but not for phospho-beta-galactosidase.
 ...
PMID:Simple Method To Detect beta-Galactosidase. 1634 81

Glycerol auxotrophs of S. aureus were isolated and shown to cease phospholipid synthesis immediately when deprived of glycerol. Second-step mutants with temperature-sensitive inducibility of the lac system were also isolated. When cells were induced by temperature shift to produce the products of the lac system in the absence of glycerol, the permease activity, relative to 6-phospho-beta-galactosidase activity, was between 30 and 50% that of glycerol-supplemented cultures. However, the phosphotransferase activity for beta-galactosides in isolated membranes was found to be normal when compared to the level of beta-galactosidase. This indicated that the permeation system was induced and integrated into the membrane, but did not function efficiently for transport. Readdition of glycerol in the presence of chloramphenicol resulted in a slow increase in efficiency of the transport activity. Glycerol deprivation after induction led to a small loss of permease efficiency.
 ...
PMID:Induction of Staphylococcus aureus Lactose Permease in the Absence of Glycerolipid Synthesis. 1659 7


<< Previous 1 2