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)

Escherichia coli cells expressing fusion proteins consisting of beta-galactosidase and bacterial heat-shock protein (HSP) 60 of E. coli, Yersinia enterocolitica or Helicobacter pylori were constructed, and designated as HY1, HY2 or HY3, respectively. Fusion proteins prepared from HY2 and HY3 induced secretion of interleukin-8 (IL-8) from human gastric epithelial KATOIII cell cultures. On the other hand, the parent strain (E. coli pop2136), PEX (pop2136 transformed by vector) and fusion protein prepared from HY1 did not induce IL-8 secretion from KATOIII cells. Other human gastric (MKN45) and non-gastric cell lines (Int 407 and A549) did not secrete IL-8 following treatment with these proteins. These results indicate that H. pylori HSP60 induces IL-8 secretion from human gastric cells and the levels of IL-8 differ among the various gastric cell lines, suggesting that HSP60 might be an important virulence factor associated with chronic gastric inflammation following H. pylori infection in man.
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PMID:Induction of secretion of interleukin-8 from human gastric epithelial cells by heat-shock protein 60 homologue of Helicobacter pylori. 1051 Sep 69

Interactions among the Yersinia secretion (Ysc) proteins of Yersinia pestis were explored using the yeast two-hybrid system. Various pairwise combinations of the yscEFGHIKLN and Q genes fused to the DNA-binding or activation domain of the yeast GAL4 gene were introduced into yeast, and expression of a reporter gene encoding beta-galactosidase was detected. Combinations of yscN and yscL, yscL and yscQ, and yscQ and yscK resulted in high levels of reporter gene activation. These results suggest that YscL interacts with both YscN and YscQ, and that YscQ interacts with both YscL and YscK. Three-hybrid analyses using plasmid pDELA to target a third hybrid protein to the yeast nucleus was used to detect the formation of ternary protein complexes. Using the three-hybrid system, YscQ expressed from plasmid pDELA was able to bring together the YscK and YscL fusion proteins. In a similar manner, YscL expressed from plasmid pDELA was able to bring together the YscN and YscQ fusion proteins. Together, these results suggest that a complex composed of YscN, YscQ, YscK and YscL is involved in the assembly and/or function of the Y. pestis type III secretion apparatus.
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PMID:Interactions between type III secretion apparatus components from Yersinia pestis detected using the yeast two-hybrid system. 1077 17

One prerequisite for the virulence of Yersinia pestis, causative agent of bubonic plague, is the yersiniabactin (Ybt) siderophore-dependent iron transport system that is encoded within a high-pathogenicity island (HPI) within the pgm locus of the Y. pestis chromosome. Several gene products within the HPI have demonstrated functions in the synthesis or transport of Ybt. Here we examine the roles of ybtU and ybtT. In-frame mutations in ybtT or ybtU yielded strains defective in siderophore production. Mutant strains were unable to grow on iron-deficient media at 37 degrees C but could be cross-fed by culture supernatants from a Ybt-producing strain of Y. pestis. The ybtU mutant failed to express four indicator Ybt proteins (HMWP1, HMWP2, YbtE, and Psn), a pattern similar to those for other ybt biosynthetic mutants. In contrast, strains carrying mutations in ybtT or ybtS (a previously identified gene required for Ybt biosynthesis) produced all four proteins at wild-type levels under iron-deprived conditions. To assess the effects of ybtT, -U, and -S mutations on transcription of ybt genes, reporter plasmids with ybtP or psn promoters controlling lacZ expression were introduced into these mutants. Normal iron-regulated beta-galactosidase activity was observed in the ybtT and ybtS mutants, whereas a significant loss of expression occurred in the DeltaybtU strain. These results show that ybtT and ybtU genes are involved in the biosynthesis of the Ybt siderophore and that a ybtU mutation but not ybtT or ybtS mutations affects transcription from the ybtP and psn promoters.
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PMID:Yersinia pestis YbtU and YbtT are involved in synthesis of the siderophore yersiniabactin but have different effects on regulation. 1089 42

Many microorganisms were isolated from condensed water, wiping and scratching of cabin wall and air sampler in Russian space station Mir by Russian astronauts Lazutkin et al. in February 1997 as part of NASDA "First MIR Utilization Space Experiment (JMIR)". For example, there were about 2 x 10(6) cells/ml in condensed water sample No. 1 isolated from the transfer-docking compartment of Crystal module. We tried the colony isolation, pure culturing and identification from these sampled microorganisms. After the bacteria separated from filamentous fungi and yeasts were observed using the phase contrast optical microscopy and gram stain method, twenty-one kinds of biochemical characters, e.g., oxidase test, activity of beta-galactosidase and fermentation of glucose etc., were investigated on the isolated bacteria. Then, we found Serratia liquefaciens and Yersinia enterocolitica and the chemoheterotroph Pseudomonadaceae, Stenotrophomonas maltophila. Furthermore, using ultraviolet (UV) lamp we tried the isolation of radioresistant bacteria, we found the radioresistant Sphingomonas paucimobilis (90.8% identification) by comparing with radioresistant Escherichia coli B/r strain. Considering Mir environment under cosmic radiation, this radioresistant S. paucimobilis might be the mutant from radiosensitive one. Following papers were published [see text].
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PMID:Microflora investigation experiment. 1179 57

One requirement for the pathogenesis of Yersinia pestis, the causative agent of bubonic plague, is the yersiniabactin (Ybt) siderophore-dependent iron transport system that is encoded within a high-pathogenicity island (HPI) within the pgm locus of the Y. pestis chromosome. Nine gene products within the HPI have demonstrated functions in the nonribosomal peptide synthesis (NRPS)/polyketide (PK) synthesis or transport of Ybt. NRPS/PK synthetase or synthase enzymes are generally activated by phosphopantetheinylation. However, no products with similarities to known phosphopantetheinyl (P-pant) transferases were found within the pgm locus. We have identified a gene, ybtD, encoded outside the HPI and pgm locus, that is necessary for function of the Ybt system and has similarities to other P-pant transferases such as EntD of Escherichia coli. A deletion within ybtD yielded a strain (KIM6-2085+) defective in siderophore production. This strain was unable to grow on iron-deficient media at 37 degrees C but could be cross-fed by culture supernatants from Ybt-producing strains of Y. pestis. The promoter region of ybtD was fused to lacZ; beta-galactosidase expression from this reporter was not regulated by the iron status of the bacterial cells or by YbtA, a positive regulator of other genes of the ybt system. The ybtD mutant failed to express indicator Ybt proteins (high-molecular-weight protein 1 [HMWP1], HMWP2, and Psn), a pattern similar to those seen with several other ybt biosynthetic mutants. In contrast, cells containing a single amino acid substitution (S2908A) in the terminal thioesterase domain of HMWP2 failed to exhibit any ybt regulatory defects but did not elaborate extracellular Ybt under iron-deficient conditions.
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PMID:Yersiniabactin production requires the thioesterase domain of HMWP2 and YbtD, a putative phosphopantetheinylate transferase. 1211 29

Yersinia ruckeri, the etiological agent of the enteric red mouth disease (ERM) of salmonids, produces Yrp1, a serralysin metalloprotease involved in pathogenesis. We describe here the hydrolytic and immunogenic properties of Yrp1. The protease was able to hydrolyze different matrix and muscle proteins as laminin, fibrinogen, gelatine, actin, and myosin but not type II and IV collagens. In addition, the Yrp1 protein, when inactivated by heat and used as an immunogen, was able to elicit a strong protection against the development of ERM. The analysis of different Y. ruckeri strains with (Azo+) or without (Azo-) Yrp1 activity showed that all of them contained the yrp1 operon. By using yrp1::lacZ operon fusions, protease production analysis, and complementation studies, it was possible to show that an Azo- strain was blocked at the transcription level. The transcriptional study of the yrp1 operon under different environmental conditions showed that it was regulated by osmolarity and temperature, without pH influence. Finally, when beta-galactosidase activity was used as a probe in vivo, the progression of the disease in the fish could be visualized, and the tropism of the bacterium and affected organs could be defined. This system opens a vast field of study not only with regard to fish disease progression but also in pathogen interactions, temporal gene expression, carrier stages, antibiotic resistance selection, etc.
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PMID:In vitro and in vivo studies of the Yrp1 protease from Yersinia ruckeri and its role in protective immunity against enteric red mouth disease of salmonids. 1466 Mar 82

Bacteriophage phiYeO3-12 is a T7/T3-related lytic phage that naturally infects Yersinia enterocolitica serotype O:3 strains by using the lipopolysaccharide O polysaccharide (O antigen) as its receptor. The phage genome is a 39,600-bp-long linear, double-stranded DNA molecule that contains 58 genes. The roles of many of the genes are currently unknown. To identify nonessential genes, the isolated phage DNA was subjected to MuA transposase-catalyzed in vitro transposon insertion mutagenesis with a lacZ' gene-containing reporter transposon. Following electroporation into Escherichia coli DH10B and subsequent infection of E. coli JM109/pAY100, a strain that expresses the Y. enterocolitica O:3 O antigen on its surface, mutant phage clones were identified by their beta-galactosidase activity, manifested as a blue color on indicator plates. Transposon insertions were mapped in a total of 11 genes located in the early and middle regions of the phage genome. All of the mutants had efficiencies of plating (EOPs) and fitnesses identical to those of the wild-type phage when grown on E. coli JM109/pAY100. However, certain mutants exhibited altered phenotypes when grown on Y. enterocolitica O:3. Transposon insertions in genes 0.3 to 0.7 decreased the EOP on Y. enterocolitica O:3, while the corresponding deletions did not, suggesting that the low EOP was not caused by inactivation of the genes per se. Instead, it was shown that in these mutants the low EOP was due to the delayed expression of gene 1, coding for RNA polymerase. On the other hand, inactivation of gene 1.3 or 3.5 by either transposon insertion or deletion decreased phage fitness when grown on Y. enterocolitica. These results indicate that phiYeO3-12 has adapted to utilize Y. enterocolitica as its host and that these adaptations include the products of genes 1.3 and 3.5, DNA ligase and lysozyme, respectively.
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PMID:Nonessential genes of phage phiYeO3-12 include genes involved in adaptation to growth on Yersinia enterocolitica serotype O:3. 1568 5

We report a significantly improved system for studying single-copy lacZ operon fusions in Yersinia enterocolitica: a simple procedure for the stable integration of lacZ operon fusions into the ara locus and a strain with a deletion mutation that abolishes the low level of endogenous beta-galactosidase activity.
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PMID:Improved system for construction and analysis of single-copy beta-galactosidase operon fusions in Yersinia enterocolitica. 1615 Nov 61

Type III machines of pathogenic Yersinia spp. transport Yop proteins across the bacterial envelope into host cells. Translational fusions of yopE to the dihydrofolate reductase gene (dhfr) or the beta-galactosidase gene (lacZ) generate hybrid proteins that block type III injection of Yop proteins into host cells, consistent with the canonical view that impassable DHFR and LacZ hybrids jam secretion machines. Mutations in repressors of posttranscriptional gene regulation, Yersinia enterocolitica yscM1 and yscM2 as well as Yersinia pestis lcrQ, relieve the YopE-DHFR-imposed blockade and restore type III injection into host cells. Genetic suppression of the type III blockade does not, however, promote YopE-DHFR secretion. A model is proposed whereby rejection of YopE-DHFR from the secretion pathway inhibits type III gene expression.
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PMID:Rejection of impassable substrates by Yersinia type III secretion machines. 1619 80

Although very little, if any, beta-galactosidase activity is detected in Yersinia pestis by a standard Miller assay, we found that Y. pestis KIM6+ cells formed blue colonies on plates containing 5-bromo-4-chloro-3-indolyl-beta-D-galactoside (X-gal). Searches of the Y. pestis genome databases revealed the presence of noncontiguous sequences highly homologous to Escherichia coli lacZ, lacY, and lacI. Yersinia pestis lacZ is predicted to encode a 1060 amino-acid protein with 62% identity and 72% similarity to beta-galactosidase from E. coli. A deletion in the Y. pestis lacZ gene caused the formation of white colonies on X-gal-containing plates and beta-galactosidase activity was at background levels in the KIM6+lacZ mutant, while the complemented strain expressed about 190 Miller units. The Y. pestis lacZ promoter was not regulated by isopropylthiogalactoside or glucose. Finally, uptake of lactose by Y. pestis may be impaired.
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PMID:Yersinia pestis lacZ expresses a beta-galactosidase with low enzymatic activity. 1643 60


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