Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: 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)

A mobilizable plasmid which carries the promoter for the exotoxin A (ETA) structural gene fused to lacZ was integrated into the chromosome of wild-type and mutant strains of Pseudomonas aeruginosa at the toxA locus by homologous recombination. beta-galactosidase synthesis in the strains (cointegrates) carrying the toxA-lacZ fusions was regulated like ETA synthesis is in P. aeruginosa. Two multicopy plasmids carrying a positive regulatory gene designated toxR were constructed which are identical except with respect to the orientation of toxR to the lacZ promoter on the plasmid. These plasmids were then introduced into P. aeruginosa cointegrate strains. When toxR was using its own promoter, synthesis of beta-galactosidase in the cointegrate strains was increased but the pattern of iron regulation was not altered. In contrast, when the lacZ promoter was directing synthesis of the toxR product in the cointegrate strains, iron regulation of beta-galactosidase and ETA synthesis were abolished.
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PMID:Regulation of exotoxin A synthesis in Pseudomonas aeruginosa: characterization of toxA-lacZ fusions in wild-type and mutant strains. 250 31

Fluorescent rhizosphere Pseudomonas sp. strain NZ130 promotes plant growth, and may do so in part because of its production of a growth inhibitory factor that is active against phytopathogenic fungi. Analysis of the inhibitory factor that is active against the phytopathogen Pythium ultimum showed that its activity is antagonized at iron concentrations above 10 microM. The iron-antagonized inhibitor was separated from the fluorescent siderophore of this pseudomonad by gel filtration. Mutants that lacked either the iron-antagonized inhibitor or the fluorescent siderophore were isolated. Results of complementation analysis of these mutants by use of a cosmid library indicated that distinct DNA sequences are required for the production of each factor. Analysis of isogenic mutant strains showed that the genetic requirements for the production of the iron-antagonized inhibitor and the fluorescent siderophore are different, and that only the fluorescent siderophore is required for iron assimilation. Fusions of these same sequences to a beta-galactosidase gene were used to show that the regions required for the production of both the fluorescent siderophore and the iron-antagonized inhibitor were iron-regulated.
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PMID:An iron-antagonized fungistatic agent that is not required for iron assimilation from a fluorescent rhizosphere pseudomonad. 282 92

Plasmid pCMS1 was isolated from Pseudomonas diminuta MG, a strain which constitutively hydrolyzes a broad spectrum of organophosphorus compounds. The native plasmid was restricted with PstI, and individual DNA fragments were subcloned into pBR322. A recombinant plasmid transformed into Escherichia coli possessed weak hydrolytic activity, and Southern blotting with the native plasmid DNA verified that the DNA sequence originated from pCMS1. When the cloned 1.3-kilobase fragment was placed behind the lacZ' promoter of M13mp10 and retransformed into E. coli, clear-plaque isolates with correctly sized inserts exhibited isopropyl-beta-D-thiogalactopyranoside-inducible whole-cell activity. Sequence determination of the M13 constructions identified an open reading frame of 975 bases preceded by a putative ribosome-binding site appropriately positioned upstream of the first ATG codon in the open reading frame. An intragenic fusion of the opd gene with the lacZ gene produced a hybrid polypeptide which was purified by beta-galactosidase immunoaffinity chromatography and used to confirm the open reading frame of opd. The gene product, an organophosphorus phosphotriesterase, would have a molecular weight of 35,418 if the presumed start site is correct. Eighty to ninety percent of the enzymatic activity was associated with the pseudomonad membrane fractions. When dissociated by treatment with 0.1% Triton and 1 M NaCl, the enzymatic activity was associated with a molecular weight of approximately 65,000, suggesting that the active enzyme was dimeric.
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PMID:Cloning and sequencing of a plasmid-borne gene (opd) encoding a phosphotriesterase. 283 39

The gene encoding the outer membrane phosphate-selective porin protein P from Pseudomonas aeruginosa was cloned into Escherichia coli. The protein product was expressed and transported to the outer membrane of an E. coli phoE mutant and assembled into functional trimers. Expression of a product of the correct molecular weight was confirmed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and Western blot (immunoblot) analysis, using polyclonal antibodies to protein P monomer and trimer forms. Protein P trimers were partially purified from the E. coli clone and shown to form channels with the same conductance as those formed by protein P from P. aeruginosa. The location and orientation of the protein P-encoding (oprP) gene on the cloned DNA was identified by three methods: (i) mapping the insertion point of transposon Tn501 in a previously isolated P. aeruginosa protein P-deficient mutant; (ii) hybridization of restriction fragments from the cloned DNA to an oligonucleotide pool synthesized on the basis of the amino-terminal protein sequence of protein P; and (iii) fusion of a PstI fragment of the cloned DNA to the amino terminus of the beta-galactosidase gene of pUC8, producing a fusion protein that contained protein P-antigenic epitopes. Structural analysis of the cloned DNA and P. aeruginosa chromosomal DNA revealed the presence of two adjacent PstI fragments which cross-hybridized, suggesting a possible gene duplication. The P-related (PR) region hybridized to the oligonucleotide pool described above. When the PstI fragment which contained the PR region was fused to the beta-galactosidase gene of pUC8, a fusion protein was produced which reacted with a protein P-specific antiserum. However, the restriction endonuclease patterns of the PR region and the oprP gene differed significantly beyond the amino-terminal one-third of the two genes.
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PMID:Cloning of the Pseudomonas aeruginosa outer membrane porin protein P gene: evidence for a linked region of DNA homology. 283 40

During a three year study 67 strains of Pseudomonas aeruginosa were isolated from stools of 67 patients with gastroenteritis. Serotypes 3 and 6 were the most frequent. The three strains that were serotype 11 were also the only beta-galactosidase producers. All strains were strongly pigmented. Over 90% of the isolates produced hemolysin, gelatinase, protease (caseinase), fibrinolysin, lecithinase and elastase. Fecal carriers of Pseudomonas aeruginosa can be considered a source of dissemination of potentially virulent and invasive strains.
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PMID:Extracellular enzymes of fecal strains of Pseudomonas aeruginosa. 283 41

We have isolated and characterized a S. pombe promoter using a functional heterologous gene product assay. Random S. pombe genomic fragments were cloned upstream from the promoterless 'lacZ gene and tested in vivo for their efficiency to promote expression of the beta-galactosidase protein in the fission yeast. An efficient S. pombe promoter called 54/1 was isolated and shown to drive up to 5% of total protein synthesis as beta-galactosidase. The structure and nucleotide sequence of this promoter were determined, precise localization of its mRNA transcriptional start points established. Translational fusion of the Pseudomonas putida XylE gene with the 54/1 gene was shown to allow expression of catechol oxidase activity in S. pombe. An expression vector suitable for transcriptional fusions was then constructed from engineered 54/1 promoter sequences and used to drive expression of the E. coli Tn5 ble gene, thus confering resistance to the fission yeast against bleomycin and phleomycin antibiotics.
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PMID:Construction of an expression vector for the fission yeast Schizosaccharomyces pombe. 284 20

A gene cloned from Xanthomonas campestris pv. vesicatoria race 2, avrBs1, specified avirulence on pepper cultivars containing the resistance gene Bs1. A series of exonuclease III deletions were made on a 3.2-kbp DNA fragment that determined full avirulence activity, observed as hypersensitive response (HR) induction. The deletion products were subcloned into the broad host range cloning vector pLAFR3, conjugated into a virulent X. c. pv. vesicatoria race 1 strain, 82-8, and scored for their ability to induce a HR on a pepper cultivar (ECW10R) containing the resistance gene Bs1. A span of approximately 1.8 kbp of DNA was necessary for full induction of the HR. The nucleotide sequence revealed two open reading frames (ORFs) capable of encoding proteins of 12.3 and 49.8 kD, designated ORF1 and ORF2, respectively. Deletions into ORF1 altered the HR-inducing activity to give an intermediate phenotype. Deletions into ORF2 completely destroyed activity. When the ORF2 coding region was driven by the lacZ promoter on plasmid pLAFR3 (placD), full avirulence activity was restored, indicating that ORF2 alone can induce the HR. Antisera raised to a beta-galactosidase-ORF2 fusion protein reacted with a 50-kD protein in X. c. pv. vesicatoria race 1 (placD) transconjugants. The deduced amino acid sequence of ORF2 had approximately 47% overall homology to the carboxyl terminus of the avirulence gene, avrA, isolated from Pseudomonas syringae pv. glycinea race 6, and 86% homology over a region of 49 amino acids. P. s. pv. glycinea, however, did not induce an HR on ECW10R plants.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:The avirulence gene avrBs1 from Xanthomonas campestris pv. vesicatoria encodes a 50-kD protein. 297 10

The structural gene for Pseudomonas aeruginosa hemolysin, carried on recombinant plasmid pSL2 and cloned in Escherichia coli, was analyzed by insertional and deletional mutagenesis. Expression of the hemolysin was blocked by insertion of transposon Tn5 into different locations. Two of the mutants allowed detectable synthesis of truncated hemolysin polypeptides of two different sizes and thus defined the structural gene. The location of the hemolysin gene in the recombinant plasmid, and the direction of transcription, were further established by nuclease BAL 31 digestion, and by construction of gene fusions between hemolysin and beta-galactosidase. Evidently, the tet promoter contributed to the majority of the expression of cloned hemolysin gene, but the Pseudomonas promoter was present in the cloned DNA and was functional in E. coli since inactivation of the tet promoter either by Tn5 insertion or by deletion decreased synthesis of the 80-kDal hemolysin but did not fully abolish it.
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PMID:Orientation and expression of the cloned hemolysin gene of Pseudomonas aeruginosa. 298 94

A method has been developed for the direct selection of methanol oxidation mutants of the facultative methylotroph Methylobacterium sp. strain AM1 (formerly Pseudomonas sp. strain AM1). Using this direct selection technique, we have isolated mutants of Methylobacterium sp. strain AM1 that are no longer capable of growth on methanol but retain the ability to grow on methylamine. These methanol oxidation (Mox) mutants were complemented with a genomic clone bank of this organism constructed in the broad-host-range cosmid pVK100, and subcloning and Tn5 mutagenesis experiments have assigned the Mox mutants to 10 distinct complementation groups. Using an open reading frame beta-galactosidase fusion vector and antibodies specific for Methylobacterium sp. strain AM1 methanol dehydrogenase, we have identified the methanol dehydrogenase structural gene and determined the direction of transcription. The results suggest that the synthesis and utilization of an active methanol dehydrogenase in this organism requires at least 10 different gene functions.
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PMID:Isolation and complementation analysis of 10 methanol oxidation mutant classes and identification of the methanol dehydrogenase structural gene of Methylobacterium sp. strain AM1. 300 11

The enzymatic activities of 53 strains of Pseudomonas cepacia were determined by using the API ZYM system. Strong alkaline phosphatase, acid phosphatase, butyrate esterase, caprylate esterase, myristate lipase, leucine arylamidase, and phosphoamidase activities were consistently detected in all strains. Weak activities were observed for valine arylamidase, beta-glucosidase, and N-acetyl-beta-glucosaminidase. No activities could be demonstrated for cystine arylamidase, trypsin, chymotrypsin, alpha-galactosidase, beta-galactosidase, beta-glucuronidase, alpha-glucosidase, alpha-mannosidase, and alpha-fucosidase. Enzymatic activities of pseudomonads may provide useful information about their pathogenesis and information for identification of Pseudomonas species.
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PMID:Enzymatic characterization of Pseudomonas cepacia by API ZYM profile. 335 98


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