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

The activator of the D-serine deaminase operon, the product of the dsdC gene, has been partially purified. It is reasonably stable to routine purification procedures in the presence of its ligand D-serine, but not in its absence. It loses activity upon dialysis in amino acid-free buffer, but activity is completely restored upon readdition of D-serine. It apparently functions purely as an activator, no repressor function could be demonstrated at suboptimal D-serine concentration. It is a transcriptional control element. The time required for in vitro transcription of D-serine deaminase mRNA, nearly 4 min, is similar to that for beta-galactosidase. Since the beta-galactosidase monomer is a much protein, this is surprisingly long.
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PMID:Role of the dsdC activator in regulation of D-serine deaminase synthesis. 21 19

A mutant of Escherichia coli is described whose cells show a spherical or irregular morphology, associated with leakage of beta-galactosidase and other intracellular proteins. The expression of the morphologic abnormality is most marked when the mutant is grown in rich media and is suppressed by D-alamine, D-serine, D-glutamate, or glycine supplementation. D-Alanine is the most effective amino acid supplement, half maximally supressing this anomalous property at a concentration of 75 mug/ml, as measured by the reduction in beta-galactosidase released from the cells. The mutant is more sensitive to penicillin G, D-methionine, and D-valine and it is relatively resistant to lysozyme. These phenotypic abnormalities are likewise corrected by the above supplementations. The relative rates of peptidoglycan synthesis in mutant and parent, grown under restrictive conditions, were measured both in vivo and in vitro by rates of incorporation of L-[14-D]alanine and uridine-5'-diphosphate-N-acetyl-D-[1-15C-A1-glucosamine, respectively. There is not metabolic block in the biosynthesis of uridine-5'-diphosphate-N-acetyl-muramyl-pentapeptide as shown by enzymic analysis and the lack of accumulation of uridine-5'-diphosphate-N-acetylmuramyl-peptide precursors. These preliminary studies suggest that the mutant possesses a defect in the biosynthesis of peptidoglycan although the exact lesion has not yet been established.
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PMID:D-Alanine-requiring cell wall mutant of Escherichia coli. 109 98

Operon fusions between the D-serine deaminase regulatory and structural genes and lacZ were constructed and used to examine the control of expression of the positive regulatory gene, dsdC. Merodiploid strains containing both dsdCp::Mu d (lac Apr) and dsdC+A+ produced only one-fourth as much beta-galactosidase as did the haploid dsdCp::Mu d (lac Apr) strains, indicating that the dsdC+ product repressed its own synthesis. The repression was reversed by D-serine. dsdC expression was not depressed in a cya background. The basal level of D-serine deaminase was the same in wild-type and dsdCp fusion strains. The dsdC gene product was identified in maxicell strains harboring dsd plasmids as a 34,000-dalton protein. dsdC gene transcription proceeded clockwise; thus, its promoter is adjacent to that of dsdA.
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PMID:Identification and control of synthesis of the dsdC activator protein. 629 57

Recently, certain environmental endocrine disrupters have shown to act as antiandrogens. This suggests that environmental antiandrogens may also be crucial contributors to the increasing incidence of male reproductive abnormalities, requesting the screening and classification of antiandrogenic chemicals. Here, we report the development of a rapid, simple and effective yeast detection system for androgenic and antiandrogenic compounds, which is based on the yeast two-hybrid protein interaction. A yeast strain, ARhLBD-ASC1, was established by co-transformation of yeast cells harboring a lacZ reporter plasmid with two vectors expressing each of LexA fused hinge-ligand binding domain (hLBD) of androgen receptor (AR) and B42 fused ASC-1 that interacts with the AR-hLBD in an androgen-dependent manner. In this yeast strain, androgens, but not other hormones, strongly stimulated the beta-galactosidase activity in a dose-dependent manner. The AR antagonists flutamide, cyproterone acetate and spironolactone, and environmental antiandrogens p,p'-DDE and vinclozolin all inhibited the response of the yeast cells to 10 nM testosterone, qualitatively similar to their inhibition reported in mammalian cell systems. Furthermore, the bioassay can be performed with the simple X-gal staining on microtiter plates, suggesting this system as a powerful tool for practical and efficient screening of environmental compounds for their androgenic and antiandrogenic activities.
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PMID:Novel yeast bioassay system for detection of androgenic and antiandrogenic compounds. 1265 Jun 78