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)

The trans-activator vir is required for expression of all virulence-associated genes in Bordetella pertussis. The nature of the global regulation of these factors by vir and environmental signals was examined by Northern blot analysis and with beta-galactosidase transcriptional fusions in five vir-regulated genes. Northern blots suggested that vir regulates at the level of transcription since Vir- organisms did not exhibit detectable mRNA from vir-regulated loci. Environmental signals such as high levels of salts, nicotinic acid, and 6-chloronicotinic acid or growth at low temperatures were examined. Of all of the cations and anions examined, only SO4 ions eliminated transcription of vir-regulated genes and reduced transcription of vir itself, suggesting that global regulation is obtained by modifying expression of the essential component, vir. Organisms grown on 6-chloronicotinic acid or quinaldic acid did not have detectable transcription from vir-regulated loci. Modulation by nicotinic acid, on the other hand, was strain dependent, acting at the level of transcription in strain 18-323 but not in Tohama I derivatives. Growth at lower temperatures reduced, but did not eliminate, transcription from vir-regulated loci. At 28 degrees C the ratio of pertussis toxin mRNA to recA mRNA (a non-vir-regulated factor) was equivalent to that at 37 degrees C, suggesting that transcription at low temperatures is reduced in a proportional manner and need not involve vir.
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PMID:Environmental regulation of expression of virulence determinants in Bordetella pertussis. 247 24

A soluble UDP-Gal: Gal (alpha 1-3) galactosyltransferase was first detected in bovine colostrum and this enzyme activity was simply assayed by using rho-nitrophenyl-beta-lactoside (Gal(beta 1-4)Glc-C6H5NO2, rho NP-lactoside) as an acceptor. Treating the radioactive product with alpha- or beta-galactosidase, the radioactivity (greater than 95%) was released by only alpha-galactosidase and was identified as [3H]galactose. This shows that galactosyl residue was alpha-linked to rho-nitrophenyl-beta-lactoside. Methylation, hydrolysis, thin layer chromatography and fluorography of the reaction product (Gal(alpha 1-)-[3H]Gal(beta 1-4)Glc-rho NP) yielded 2,4,6-tri-O-methyl[3H]galactose, indicating that galactosyl residue had been transferred to the carbon-3 position of the terminal nonreducing beta-galactosyl residue in rho-nitrophenyl-beta-lactoside. These results confirmed that the structure of the reaction product was Gal(alpha 1-3)Gal(beta 1-4)Glc-rho NP. The enzyme requires Mn2+ for its activity, and shows pH optimum from 6.5 to 7.5. rho-Nitrophenyl-beta-lactoside and asialo alpha 1-acid glycoprotein were more effective as an acceptor than N-acetyllactosamine. The bovine colostrum (alpha 1-3) galactosyltransferase could not convert human O red cells into B active cells, indicating that this enzyme preparation did not contain the activity to synthesize human blood group B erythrocytes.
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PMID:Identification of a soluble UDP-Gal: Gal (beta 1-4)Glc (or GlcNAc) (alpha 1-3) galactosyltransferase of bovine colostrum. 251 15

The production of high-mass quasimolecular ions from proteins by matrix-assisted ultraviolet laser desorption is described. A simple time-of-flight system using a Q-switched frequency-quadrupled Nd-YAG laser to desorb protein molecules is shown to have a mass range of up to 116,000 u by the observation of intact, singly charged quasimolecular ions from 700 fmol of beta-galactosidase subunit (mol.wt = 116,336 Da). Both positive- and negative-ion spectra of proteins are shown. Four new matrix materials, with properties as good as or better than nicotinic acid, are described. A mass resolution of approximately 500 (full width at half maximum definition) is demonstrated for proteins with mol.wt less than 20,000 Da. Product species, formed by fast photochemical reactions in the matrix, are observed to form adduct ions with protein molecules. These adduct ions are a significant cause of the observed broadness of protein quasimolecular ion peaks. The practical physical considerations in detection of large-mass quasimolecular ions from laser desorption, such as detector overloading, are discussed.
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PMID:Factors affecting the ultraviolet laser desorption of proteins. 252 Feb 42

The virulence regulon of Bordetella pertussis includes a trans-acting regulatory locus, bvg, that is required for expression of several virulence factors. The virulence control system also responds to environmental signals. We have reconstructed a bvg-dependent regulatory system in Escherichia coli by using bacteriophage lambda vectors carrying transcriptional fusions to lacZYA. Single-copy lacZYA fusions to the B. pertussis fhaB locus, which encodes the attachment factor filamentous hemagglutinin, were activated nearly 400-fold by pBR322 replicons carrying sequences that included bvg. In contrast, bvg had no effect on the pertussis toxin operon (ptxA-E) promoter in E. coli as measured by ptxA-lacZ expression. Environmental signals that modulate expression of virulence genes in B. pertussis had a pronounced effect on bvg-mediated activation of fhaB-lacZ. MgSO4, nicotinic acid, and low temperature resulted in decreases in beta-galactosidase activities of 175-, 115-, and 45-fold respectively. Sensory transduction and transcriptional activation were tightly coupled, and both required an intact bvg locus as determined by 5' and 3' deletions that eliminated both activities.
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PMID:Analysis of Bordetella pertussis virulence gene regulation by use of transcriptional fusions in Escherichia coli. 255 78

Pulmonary alveolar macrophages exposed to very short chrysotile asbestos fibers present a typical cytotoxic response: extracellular releases of lactate dehydrogenase and beta-galactosidase, and a decrease in cellular ATP content. The objective of this study was to determine if nicotinamide and 3-aminobenzamide, two inhibitors of the ADP-ribosyl transferase, could modify the in vitro toxicity of chrysotile fibers. After 30 min of pre-exposure with each of the two inhibitors, pulmonary alveolar macrophage monolayers were concomitantly exposed for 18 hours to 50 micrograms of fibers. It was observed that, in a dose-effect relationship (5 to 30 mM), nicotinamide was very effective in reducing the extracellular liberation of the marker enzymes. At 30 mM, the enzyme releases in the medium had returned to control values; the restoration of cell viability was confirmed by ATP levels. Up to 5 mM 3-aminobenzamide did not provide any protection against chrysotile cytotoxicity. Nicotinic acid, a structural analogue of nicotinamide, but not an inhibitor of the ADP-ribosyl transferase, also showed no protective effect. Nicotinamide and 3-aminobenzamide increased the intracellular NAD+ pools, respectively by 350% and 250%. However, with or without additives, the chrysotile fibers caused a constant and significant decrease in NAD+ levels (40-55 pmoles). These results suggest that the inhibition of the nuclear ADP-ribosyl transferase is not the major mechanism by which nicotinamide protects pulmonary alveolar macrophages against the toxicity of chrysotile asbestos fibers.
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PMID:The cytotoxicity of chrysotile asbestos fibers to pulmonary alveolar macrophages. I. Effects of inhibitors of ADP-ribosyl transferase. 285 30

Strains of a new type of slowly growing mycobacterium were repeatedly isolated from sputum from a patient with pulmonary disease. This photochromogenic organism grew at 22, 31, 37, and 41 degrees C, possessed catalase, acid phosphatase, esterase, beta-galactosidase, and arylsulfatase activities, and hydrolyzed Tween. It did not produce nicotinic acid or have nitrate reductase, acetamidase, benzamidase, isonicotinamidase, nicotinamidase, pyrazinamidase, succinidamidase, and acid phosphatase activities. Urease activity was variable. The organism is susceptible to ethambutol and resistant to isoniazid and streptomycin. A mycolic acid analysis revealed the presence of alpha-mycolates, alpha'-mycolates, and keto-mycolates. The results of comparative 16S rRNA sequencing placed this organism at an intermediate position between the rapidly and slowly growing mycobacteria. On the basis of the pattern of enzymatic activities and metabolic properties, the results of fatty acid analyses, and the unique 16S rRNA sequence, we propose that this organism represents a new species, for which we propose the name Mycobacterium intermedium. The type strain is strain 1669/91; a culture of this strain has been deposited in the Deutsche Sammlung von Mikroorganismen und Zellkulturen as strain DSM 44049.
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PMID:Mycobacterium intermedium sp. nov. 849 35