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 5 kb region upstream of katA at 82 degrees on the Bacillus subtilis chromosome contains five ORFs organized in an operon-like structure. Based on sequence similarity, three of the ORFs are likely to encode an ABC transport system (ssuBAC) and another to encode a monooxygenase (ssuD). The deduced amino acid sequence of the last ORF (ygaN) shows no similarity to any known protein. B. subtilis can utilize a range of aliphatic sulfonates such as alkanesulfonates, taurine, isethionate and sulfoacetate as a source of sulfur, but not when ssuA and ssuC are disrupted by insertion of a neomycin-resistance gene. Utilization of aliphatic sulfonates was not affected in a strain lacking 3'-phosphoadenosine 5'-phosphosulfate (PAPS) sulfotransferase, indicating that sulfate is not an intermediate in the assimilation of sulfonate-sulfur. Sulfate or cysteine prevented expression of beta-galactosidase from a transcriptional ssuD::lacZ fusion. It is proposed that ssuBACD encode a system for ATP-dependent transport of alkanesulfonates and an oxygenase required for their desulfonation.
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PMID:Bacillus subtilis genes for the utilization of sulfur from aliphatic sulfonates. 978 4

We describe a new chromogenic agar medium, ABC medium (alphabeta-chromogenic medium), which includes two substrates, 3, 4-cyclohexenoesculetin-beta-D-galactoside and 5-bromo-4-chloro-3-indolyl-alpha-D-galactopyranoside, to facilitate the selective isolation of Salmonella spp. This medium exploits the fact that Salmonella spp. may be distinguished from other members of the family Enterobacteriaceae by the presence of alpha-galactosidase activity in the absence of beta-galactosidase activity. A total of 1, 022 strains of Salmonella spp. and 300 other gram-negative strains were inoculated onto this medium. Of these, 1,019 (99.7%) strains of Salmonella spp. produced a characteristic green colony, whereas only 1 strain (0.33%) of non-Salmonella produced a green colony. A total of 283 stool samples were cultured onto desoxycholate citrate (DC) agar and ABC medium by direct inoculation and after selective enrichment in selenite broth. Overall, the sensitivity and specificity were superior for ABC medium (100 and 90.5%, respectively) than for DC agar (88 and 26.9%, respectively). We conclude that ABC medium offers a high degree of specificity for the detection of Salmonella spp. in stool samples.
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PMID:ABC medium, a new chromogenic agar for selective isolation of Salmonella spp. 998 48

The growth properties of an Escherichia coli strain carrying a chromosomal deletion of the ssuEADCB genes (formerly designated ycbPONME) indicated that the products of this gene cluster are required for the utilization of sulfur from aliphatic sulfonates. Sequence similarity searches indicated that the proteins encoded by ssuA, ssuB, and ssuC are likely to constitute an ABC type transport system, whereas ssuD and ssuE encode an FMNH(2)-dependent monooxygenase and an NAD(P)H-dependent FMN reductase, respectively (Eichhorn, E., van der Ploeg, J. R., and Leisinger, T. (1999) J. Biol. Chem. 274, 26639-26646). Synthesis of beta-galactosidase from a transcriptional chromosomal ssuE'-lacZ fusion was repressed by sulfate or cystine and depended on the presence of a functional cbl gene, which encodes a LysR-type transcriptional regulator. Electrophoretic mobility shift assays with the ssu promoter region and measurements of beta-galactosidase from plasmid-encoded ssuE'-'lacZ fusions showed that full expression of the ssu operon required the presence of a Cbl-binding site upstream of the -35 region. CysB, the LysR transcriptional regulator for the cys genes, was not required for expression of a chromosomal ssuE'-lacZ fusion although the ssu promoter region contained three CysB-binding sites. Integration host factor could also occupy three binding sites in the ssu promoter region but had no influence on expression of a chromosomal ssuE'-lacZ fusion.
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PMID:The Escherichia coli ssuEADCB gene cluster is required for the utilization of sulfur from aliphatic sulfonates and is regulated by the transcriptional activator Cbl. 1050 96

Previously, we demonstrated successful Tn917 mutagenesis of the oral pathogen Streptococcus mutans using pTV1-OK (Km(r), repATs), a temperature conditional replicative delivery vector carrying a lactococcal pWVO1Ts backbone. In this report we describe the construction and utilization of pTV32-OK, a plasmid harboring Tn917-lac (em(r), beta-gal(+)) that was employed to isolate transcriptional fusions of the Escherichia coli lacZ reporter gene with streptococcal promoters in S. mutans strain NG8. Tn917-lac transposition occurred at a frequency of ca. 10(-6) with 20% of the resultant em(r) clones displaying varying levels of lacZ expression. Tn917-lac mutants that expressed beta-galactosidase activity under growth conditions of glucose limitation, acidic pH, 35 mM NaCl, and elevated (42 degrees C) temperature were isolated. Further characterization of one of the mutants with increased beta-gal activity under glucose limitation, strain AS42, revealed maximal activity in batch culture in stationary phase after glucose depletion. The beta-gal activity of AS42 also was found to be repressed 3-fold in medium containing 2% glucose relative to measured activity from cells suspended in the same medium containing no glucose. Further phenotypic analysis revealed that AS42 had a 30% lower growth yield than the parent strain NG8 when grown in pH 5 medium. Sequence analysis of the region harboring the transposon revealed that the lacZ fusion occurred near the 3'-end of a gene encoding a homolog of an ATP binding protein from a family of Gram-positive ABC transporters. These findings demonstrate that Tn917-lac mutagenesis can be used to identify environmentally regulated genes in S. mutans and possibly in other medically relevant streptococcal species.
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PMID:Tn917-lac mutagenesis of Streptococcus mutans to identify environmentally regulated genes. 1061 47

We have transiently expressed decorin with a C-terminal KDEL endoplasmic reticulum retention signal peptide in COS-7 cells to study initiation of galactosaminoglycan synthesis in the endoplasmic reticulum-Golgi intermediate compartment. All decorin-KDEL molecules were substituted with N-linked oligosaccharides sensitive to endoglycosidase H, indicating that the core protein was located proximal to the medial-Golgi. O-Linked glycosylation was only initiated in a minor fraction of the molecules. The O-linked saccharides were characterized by gel filtration after stepwise degradations using chondroitin ABC/AC-I lyases, beta1-3-glycuronidase, beta-galactosidase, and alkaline phosphatase. The major O-linked saccharide was the linkage region pentasaccharide GalNAcbeta1-4GlcUAbeta1-3Galbeta1-3Galbeta1-4Xyl-2-phosphate, demonstrating initiation of chondroitin synthesis in the endoplasmic reticulum-Golgi intermediate compartment. In the presence of brefeldin A, partial elongation of a chondroitin chain took place, indicating retrieval of polymerases but not of sulfotransferases.
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PMID:Initiation of the decorin glycosaminoglycan chain in the endoplasmic reticulum-Golgi intermediate compartment. 1266 76

Certain peptides containing high percentage of cationic amino acids are known to efficiently translocate through the cell membrane. This principle was previously exploited for delivery of variety proteins. We had observed that various basic peptides of earlier studies, though not specifically use for gene delivery, contain DNA or RNA binding domains. In the present study, we reported on arginine peptides, which form DNA complexes that efficiently transfect various cell lines. The transfection abilities of the peptides were observed by green fluorescent protein (GFP) and beta-galactosidase gene expression in 293T, HeLa, Jurkat, and COS-7 cells. We found superior transfection activity of arginine peptides compared with commercially available efficient transfection agents. The expression of marker genes induced by arginine peptides was partially inhibited in the presence of heparan sulfate, chondroitin sulfate B and C, or both heparinase III and chondroitinase ABC. The transfection proficiency of these peptides was affected by endosomotropic reagent as well as low temperature (4 degrees C). Finally, we have investigated the potential of arginine peptides as a delivery agent for gene therapy, by attempting to deliver herpes simplex virus thymidine kinase (HSV-TK) gene into tumor cells. HSV-TK transfected tumor cells exhibited sensitivity to the antiviral drug ganciclovir (GCV), leading to cell death. Taken together, these data demonstrate that arginine peptide is proficient for transfection, indicating its potentially benefit to studies in gene therapy and gene delivery in a range of model organisms.
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PMID:Basic peptide system for efficient delivery of foreign genes. 1272 22

In Saccharomyces cerevisiae, disruption of the YCF1 gene increases the sensitivity of cell growth to mercury. Transformation of the resulting ycf1 null mutant with a plasmid harbouring YCF1 under the control of the GAL promoter largely restores the wild-type resistance to the metal ion. The protective effect of Ycf1p against the toxicity of mercury is especially pronounced when yeast cells are grown in rich medium or in minimal medium supplemented with glutathione. Secretory vesicles from S. cerevisiae cells overproducing Ycf1p are shown to exhibit ATP-dependent transport of bis(glutathionato)mercury. Moreover, using beta-galactosidase as a reporter protein, a relationship between mercury addition and the activity of the YCF1 promoter can be shown. Altogether, these observations indicate a defence mechanism involving an induction of the expression of Ycf1p and transport by this protein of mercury-glutathione adducts into the vacuole. Finally, possible coparticipation in mercury tolerance of other ABC proteins sharing close homology with Ycf1p was investigated. Gene disruption experiments enable us to conclude that neither Bpt1p, Yor1p, Ybt1p nor YHL035p plays a major role in the detoxification of mercury.
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PMID:Ycf1p-dependent Hg(II) detoxification in Saccharomyces cerevisiae. 1275 4

Cytochrome bd is a respiratory quinol oxidase in Escherichia coli. Besides the structural genes (cydA and cydB) encoding the oxidase complex, the cydD and cydC genes, encoding an ABC-type transporter, are required for assembly of this oxidase. Recently, cysteine has been identified as a substrate (allocrite) that is transported from the cytoplasm by CydDC, but the mechanism of cysteine export to the periplasm and its role there remain unknown. To initiate an understanding of structure-function relationships in CydDC, its membrane topography was analysed by generating protein fusions between random and selected residues in the two polypeptides with both alkaline phosphatase and beta-galactosidase. CydD and CydC are experimentally shown each to have six transmembrane segments, two major cytoplasmic loops and three minor periplasmic loops; both termini of each protein face the cytoplasm. The cydD1 allele is shown to have two point mutations (G319D, G429E) within the ATP-binding domain of CydD; either mutation alone is sufficient to cause loss or severe reduction of cytochrome bd assembly. A comparative sequence analysis prompted the targeting of residues in CydD for site-directed mutational analysis, which identified (i) the 'start' methionine residue, (ii) essential residues in the ATP-binding site (Walker sequence A) and (iii) a duplicated positively charged heptameric motif, R-G/T-L/M-X-T/V-L-R, in CydD cytoplasmic loop II. The replacement of arginines in these motifs with glycines resulted in Cyd- phenotypes; however, activity could be restored at these positions by replacing the glycine with lysine or histidine and hence returning the positive charge. The conservation of these charges in CydD-like proteins indicates functional importance. Evolutionary aspects of bacterial cyd genes are discussed.
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PMID:Membrane topology and mutational analysis of Escherichia coli CydDC, an ABC-type cysteine exporter required for cytochrome assembly. 1547 Jan 19

Wild-type V. vulnificus cannot grow using lactose as the sole carbon source or take up the sugar. However, prolonged culture of this species in media containing lactose as the sole carbon source leads to the generation of a spontaneous lactose-utilizing (LU) mutant. This mutant showed strong beta- galactosidase activity, whereas the wild-type strain showed a barely detectable level of the activity. A mutant with a lesion in a gene homologous to the lacZ of E. coli in the bacterium no longer showed beta-galactosidase activity or generated spontaneous LU mutants, suggesting that the lacZ homolog is responsible for the catabolism of lactose, but the expression of the gene and genes for transport of lactose is tightly regulated. Genetic analysis of spontaneous LU mutants showed that all the mutations occur in a lacI homolog, which is located downstream to the lacZ and putative ABC-type lac permease genes. Consistent with this, a genomic library clone containing the lacI gene, when present in trans, made the spontaneous LU mutants no longer able to utilize lactose as the sole carbon source. Taken together with the observation that excessive amounts of exogenously supplemented possible catabolic products of lactose have negative effects on the growth and survivability of V. vulnificus, we suggest that V. vulnificus has evolved to carry a repressor that tightly regulates the expression of lacZ to keep the intracellular toxic catabolic intermediates at a sublethal level.
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PMID:Genetic analysis of spontaneous lactose-utilizing mutants from vibrio vulnificus. 1816 54

To investigate the molecular basis of multiple-allele-inherited male sterility in Chinese cabbage (Brassica campestris L. ssp. pekinensis), we performed differential proteomic analysis using iTRAQ to identify differentially abundant proteins between fertile and sterile flower buds from the genetic male sterile line 'AB01'. We identified 5932 high-confidence proteins; 1494 were differentially abundant between the two samples, including 749 up- and 745 down-regulated proteins. The up- and down-regulated proteins that could be essential for anther development and male sterility in sterile buds were mainly involved in (1) carbohydrate and energy metabolism (pyruvate dehydrogenase, glycolysis/gluconeogenesis, TCA cycle, starch and sucrose metabolism), (2) pollen wall synthesis and regulation (pectinesterase, polygalacturonase, pectate lyase, beta-galactosidase, glycosyl hydrolase), (3) protein synthesis and degradation (proteasome subunits, ribosome proteins, ABC transporters, RNA transport, protein processing in endoplasmic reticulum), (4) flavonoid biosynthesis, and (5) plant hormone signal transduction. We identified 10 genes/proteins that were both up-regulated and 122 that were both down-regulated in a conjoint analysis. Multiple reaction monitoring and qRT-PCR validation showed that the iTRAQ results were accurate and reliable. These findings will provide valuable information on proteins involved in anther development, and will contribute to the understanding of the molecular mechanism(s) that underlie male sterility in Chinese cabbage. BIOLOGICAL SIGNIFICANCE: Chinese cabbage is an allogamous plant with bisexual flowers that displays significant heterosis. The application of male sterile lines is a very efficient way to produce hybrid seeds, which can generate stronger plants that develop more rapidly and produce higher yield. However, the molecular mechanism(s) underlying multiple-allele-inherited male sterility in Chinese cabbage is unknown. In this study, we used a quantitative proteomic approach (iTRAQ) to identify DAPs between fertile and sterile buds of the GMS line 'AB01'. Subsequently, we also performed conjoined analysis of the iTRAQ results and our previously reported transcriptomics results. The aim of this research was to obtain the key DAPs and to identify the significantly enriched pathways involved in anther development and male sterility. These results may provide new insights into the molecular mechanism(s) underlying multiple-allele-inherited male sterility in Chinese cabbage.
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PMID:iTRAQ-based proteomic analysis of fertile and sterile flower buds from a genetic male sterile line 'AB01' in Chinese cabbage (Brassica campestris L. ssp. pekinensis). 3114 48


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