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 chitinase (Cht)-encoding gene from Streptomyces plicatus was previously cloned and expressed in Escherichia coli [Robbins et al., J. Biol. Chem., 263 (1988) 442-447]. We have sequenced this gene, compared its sequence with other genes encoding Cht and have explored its expression and regulation when reintroduced into Streptomyces lividans on multicopy plasmids. We have also cloned two other Streptomyces Cht-encoding genes and a beta-hexosaminidase-encoding gene in E. coli by expression in the lambda ZAP-Bluescript vector. The hexosaminidase and one of the Chts were expressed directly from the genomic library in E. coli at a high level as chimeric fusions with the beta-galactosidase alpha-complementing peptide encoded by the vector. Direct cloning and high-level expression of such chimeric proteins, which overcomes the difficulties associated with expressing Streptomyces genes in E. coli, should generally be possible wherever large numbers of transformants can be conveniently screened.
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PMID:Cloning and high-level expression of chitinase-encoding gene of Streptomyces plicatus. 153 61

The genomic DNA of two strains of the entomopathogenic fungus Beauveria bassiana, strain GK2016, a "wild type" (virulent), and strain GK2051, a less virulent mutant to grasshoppers, was digested with 12 restriction endonucleases. Gel electrophoresis conditions were established to show restriction fragment length patterns visually in the digested DNA stained with ethidium bromide. The less virulent mutant was generated by ultraviolet illumination of conidiospores at a 95% lethal dose. Both strains of the fungi were identical in morphology as well as in 16 of 22 API-ZYM kit enzyme assays. Differences in levels of total enzyme activity were observed for esterase, esterase-lipase, beta-galactosidase, chitinase, and protease. A Neurospora crassa beta-tubulin gene (heterologous gene) and two homologous DNA probes (pJK16 and pJK18) hybridized to several specific DNA bands in B. bassiana strain GK2016 but not in strain GK2051. Strain GK2051 gave different restriction fragment length pattern when compared with its parent strain. Taken together, the data show restriction fragment length differences between the genomic DNA of the two strains, including the loss of some DNA sequences from the mutant strain, which may be involved in pathogenicity. Finally, B. bassiana GK2016 contains a beta-tubulin gene with at least partial homology to that of N. crassa.
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PMID:Genomic analysis of a virulent and a less virulent strain of the entomopathogenic fungus Beauveria bassiana, using restriction fragment length polymorphisms. 168 May 43

4-Methylumbelliferyl (4-MU) glycosides of N-acetylglucosamine oligosaccharides were used as substrates to detect expression of a Streptomyces chitinase in Escherichia coli. Low levels of enzyme were detected when S. plicatus DNA was cloned into a bacteriophage lambda vector (EMBL-4). Subcloning into E. coli plasmids also gave low but detectable levels of enzyme expression. High level expression was achieved by resection of the cloned S. plicatus DNA with Bal31 followed by in-frame fusion to the amino-terminal peptide sequence of beta-galactosidase found in the pUC vectors. The Streptomyces chitinase was secreted into the periplasmic space of E. coli, and its signal sequence was removed. We characterized the activity of the cloned enzyme and compared it to three other purified Streptomyces plicatus chitinases with respect to hydrolysis of the 4-MU oligosaccharides. We found that two of the enzymes form 4-methylumbelliferone much more rapidly from the 4-MU disaccharide than from the trisaccharide. These same enzymes convert the 4-MU trisaccharide primarily to diacetylchitobiose and the 4-MU monosaccharide, a nonfluorescent product. The latter compound is not hydrolyzed appreciably by any of the enzymes. On the basis of these results, we suggest a new definition of "exo" and "endo" chitinase that differs from that found in the literature. We propose that exochitinase activity be defined as processive action starting at the nonreducing ends of chitin chains with release of successive diacetylchitobiose units, and that endochitinase activity be defined as random cleavage at internal points in chitin chains.
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PMID:Cloning and expression of a Streptomyces plicatus chitinase (chitinase-63) in Escherichia coli. 327 46

One hundred twenty-seven isolates of Aeromonas comprising the three currently recognizable species (A. hydrophila, A. sobria, and A. caviae) were evaluated for biochemical and exoenzymatic properties. Aeromonas species were generally (greater than 90%) characterized as gram-negative fermentative rods that were oxidase-, catalase-, and beta-galactosidase-positive, produced arginine dihydrolase, and failed to decarboxylate ornithine. More than 95% of all isolates tested failed to grow on 6.5% salt or thiosulfate-citrate bile salts agar and were resistant to the vibriostatic agent 0/129. Most Aeromonas species produced acid from hexoses while failing to ferment alcoholic sugars or trisaccharides. In exoenzymatic studies, Aeromonas species were uniformly found to produce several exoenzymes, including amylase, DNase, RNase, esterase, lipase, gelatinase, protease, fibrinolysin, and chitinase. Within the genus, a number of biochemical and enzymatic properties were found to be associated with one or more of the taxonomically recognizable species. These properties included glycoside utilization, Heiberg grouping based upon fermentation of arabinose, sucrose, and mannose, and the elaboration of several extracellular enzymes (elastase, hemolysin, lecithinase, phosphatase). In addition, phenotypic markers previously associated with enterotoxigenic Aeromonas isolates were almost exclusively found among A. hydrophila and A. sobria species, suggesting that these species are the major enteric pathogens.
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PMID:Biochemical and exoenzymatic properties of Aeromonas species. 388 8

Since 1988 an endoglucosaminidase, provisionally named MU-TACT hydrolase, has been known that hydrolyses the artificial substrate 4-methylumbelliferyl-tetra-N-acetyl-chitotetraoside (MU-[GlcNAc]4, where GlcNAc is N-acetylglucosamine). The biological function of the enzyme was unknown. In this paper evidence is presented showing that this endoglucosaminidase from human serum is in fact a chitinase that is different from lysozyme. The facts sustaining this finding are: (i) the identification of the products formed from MU-[GlcNAc]3 and [GlcNAc]2;and [GlcNAc]3; (ii) chitin and ethylene glycolchitin can be degraded by the enzyme; (iii) the chitinase inhibitor allosamidin also inhibits the action of MU-TACT hydrolase from human serum; (iv) no hydrolysis of the lysozyme substrate Micrococcus lysodeikticus. The enzyme also occurs in rat liver. It was demonstrated that upon Percoll density gradient centrifugation the enzyme from this tissue distributed parallel to the lysosomal marker enzymes beta-N-acetylhexosaminidase and beta-galactosidase, indicating a lysosomal localization for this enzyme. It is proposed that the enzyme functions in the hydrolysis of chitin, to which mammals are frequently exposed during infection by pathogens.
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PMID:Human serum contains a chitinase: identification of an enzyme, formerly described as 4-methylumbelliferyl-tetra-N-acetylchitotetraoside hydrolase (MU-TACT hydrolase). 773 43

Serine proteinases of 42, 22 and 14 kDa were purified from the culture fluid of Streptomyces olivaceoviridis by FPLC. The first 14 amino acids at their N-termini were identical and coincide with the N-terminal amino acid sequence of 92-kDa chitinase, which was found to hydrolyse casein. The four proteins hydrolyse synthetic substrates at the carboxyl group of lysine and (more slowly) arginine. The 14-kDa endoproteinase releases only two fragments of 42 and 43 kDa from beta-galactosidase. When the pure 92-kDa chitinase was incubated at 37 degrees C in Tris.HCl buffer, it was cleaved into a 70-kDa chitinase and a 22-kDa proteinase which in its part is rapidly degraded to a 14-kDa proteinase.
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PMID:The 92-kDa chitinase from Streptomyces olivaceoviridis contains a lysine-C endoproteinase at its N-terminus. 805 94

The presence of chitinase activity in human serum has recently been described by us. On that occasion we speculated on the possible role of mammalian chitinases as a defense mechanism against chitin-containing pathogens. The results of the present study substantiate our hypothesis. We demonstrate and partially characterize the chitinase activities that are present in plasma of guinea pigs and in homogenates of A.fumigatus with the aid of the substrates MU-[GlcNAc]2,3 and also with glycol [3H]chitin. Upon infection with A.fumigatus the serum chitinase activity levels in the circulation of pathogen-free guinea pigs increased in a time-dependent manner. The increase was also dependent on the size of the infecting fungal inoculum. Antifungal treatment diminished the increases. The increased chitinase activity was of guinea pig origin. The activity of beta-hexosaminidase showed a very slight increase subsequent to the infection. The activities of three other enzymes of lysosomal origin (alpha-mannosidase, beta-galactosidase and beta-glucosidase) did not increase.
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PMID:Chitinase levels in guinea pig blood are increased after systemic infection with Aspergillus fumigatus. 892 58

Sequence data for genes encoding 16S rRNA indicated that the marine strain previously named Pseudomonas sp. strain S9 would be better identified as a Pseudoalteromonas sp. By use of transposon mutagenesis, a chitinase-negative mutant of S9 with a lacZ reporter gene insertion was isolated. Part of the interrupted gene was cloned and sequenced. The deduced amino acid sequence had homology to sequences of bacterial chitinases. Expression of the chitinase gene promoter was quantified by measuring the lacZ reporter gene product, beta-galactosidase, beta-Galactosidase production was induced 10-fold by N-acetylglucosamine and 3-fold by chitin in minimal medium. Repression of beta-galactosidase synthesis was observed in rich medium either with or without chitin but was not observed in minimal medium containing glucose. The chitinase gene promoter was induced by starvation and higher-than-ambient levels of carbon dioxide but not by cadmium ion, heat or cold shock, or UV exposure.
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PMID:Use of a promoterless lacZ gene insertion to investigate chitinase gene expression in the marine bacterium Pseudoalteromonas sp. strain S9. 925 Nov 87

We cloned a chitinase-encoding gene from Aspergillus nidulans by polymerase chain reaction using degenerated oligonucleotide primers designed from the conserved amino acid sequences among chitinases from yeasts and Rhizopus spp. The cloned gene, named chiA, encoded a polypeptide consisting of 660 amino acids. Disruption of chiA had no effect on hyphal or conidiophore morphology, but germination frequency and hyphal growth rate decreased substantially. Expression of chiA was investigated using Escherichia coli beta-galactosidase as a reporter enzyme. The beta-galactosidase activity was present during hyphal growth and increased twice as the conidiophores developed. In situ staining of beta-galactosidase activity found high expression in metulae, phialides, and conidia during conidiophore development, indicating that the expression of chiA is developmentally regulated. This is the first report to isolate a chitinase gene from A. nidulans and investigate its functions using the gene disruption technique and gene fusion methods in filamentous fungi.
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PMID:Cloning and characterization of a chitinase-encoding gene (chiA) from Aspergillus nidulans, disruption of which decreases germination frequency and hyphal growth. 950 18

Oviduct-specific glycoprotein (OGP) is a high molecular weight glycoprotein belonging to the chitinase protein family. OGPs are found to associate with the zona pellucida and plasma membrane of the oocyte and developing embryo. Recent studies have shown that OGP plays an important role in pre-fertilization reproductive events (i.e. sperm capacitation, sperm-zona binding and zona penetration). To have a better understanding of human OGP (HuOGP) gene expression, a 3.3 kb DNA fragment containing the 5'-flanking and the intron I region of the HuOGP gene was isolated. DNA sequence analysis of the HuOGP putative promoter revealed little homology with its hamster and mouse ogp gene counterparts. One transcription initiation site was found 12 nucleotides upstream of the first ATG codon of the HuOGP gene. The HuOGP gene promoter lacked typical CAAT or GC boxes, but contained eight half estrogen-responsive elements (ERE) and an imperfect ERE (iERE; 5'-GGTCANNNTGACT-3') site. Deletion mutants of the 3.3 kb DNA fragment were generated and fused to a promoterless beta-galactosidase (beta-Gal) gene. Transfection studies revealed that in the presence of 100 nmol/l estradiol-17 beta (E(2)), a minimal 0.3 kb promoter construct (pH-298/+25 beta Gal) mediated a high level of beta-Gal expression in immortalized human oviductal epithelial OE-E6/E7 cells, but not in MCF-7 and CHO-K1 cells. By electromobility shift assay and specific estrogen receptor antibodies, we demonstrated that estrogen receptor beta present in the OE-E6/E7 cells binds to the iERE. These findings allow a better understanding of the regulation of OGP gene expression in the human oviduct.
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PMID:Cloning and characterization of the human oviduct-specific glycoprotein (HuOGP) gene promoter. 1181 19


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