Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Infection of both cattle and humans with Salmonella dublin can result in septicemia and death. Like many nontyphoid Salmonella species that cause disease, S. dublin contains a cryptic plasmid (pSDL2) that is required for the full expression of virulence. Transposon mutagenesis of pSDL2 defined a 4.1-kb EcoRI region that is necessary for the development of a systemic infection in BALB/c mice. This EcoRI fragment was cloned into an expression vector (pEL11), and three proteins produced from this region with apparent molecular weights of 30,500, 76,000, and 27,000 were identified. Because bacterial proteins that play a role in virulence are often associated with the outer membrane, we were interested in establishing whether the proteins expressed from the EcoRI fragment are located in the membrane. Transposon mutagenesis of pEL11 with TnphoA defined the order of the genes along the fragment and suggested that the proteins may be exported out of the cytoplasm. Sucrose gradient cell fractionation was done to identify the cellular location of each of the three proteins. The 30-kDa protein was identified in the outer membrane fraction, and the 76-kDa protein was located in the cytosolic fraction. The 27-kDa protein was identified in both the cytosolic and the outer membrane fractions. The outer membrane contained less than 10% of the activity of enzymes known to be located in the cytoplasm, periplasm, and inner membrane. Sequence data of the 4.1-kb EcoRI region revealed that both the 30- and the 27-kDa proteins lack a typical signal sequence for export out of the cytoplasm (M. Krause, C. Roudier, J. Fierer, J. Harwood, and D. G. Guiney, Mol. Microbiol. 5:307, 1991). The outer membrane location of these proteins suggests that they may be exported out of the cytoplasm by an unusual mechanism.
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PMID:Characterization of three proteins expressed from the virulence region of plasmid pSDL2 in Salmonella dublin. 165 1

Infection of the cervix uteri with various types of human papillomaviruses is generally considered a necessary factor in the etiology of cancer of the cervix uteri. In many human populations throughout the world, approximately 90% of cervical carcinomas are found to harbour HPV genomes, as judged by Southern blot hybridization, while only a few percent of the cervical smears of asymptomatic individuals contain viral DNA, as assessed by filter in situ hybridization. To obtain corresponding epidemiological data from Singapore, we analysed two groups of 740 and 130 individuals by filter in situ hybridization, and found 4.1% and 6.9% of them to be HPV positive, with HPV 16 and HPV 31 being the predominant types. In consideration of the limitations of filter in situ hybridization, namely low sensitivity and a tendency to suggest false positives due to contaminants, including blood, we analysed the cervical smears of two further groups of 52 and 50 individuals by the polymerase chain reaction for infection by HPV 16 and HPV 18 respectively. With this test, 61% and 14% of the cervical smears proved to be HPV 16 and HPV 18 DNA positive respectively. We conclude that in Singapore, if not worldwide, the majority of the population the population is infected by genital HPV types, suggesting that factors other than HPV infection are ultimately rate-limiting in cervical carcinogenesis.
Mol Cell Probes 1990 Apr
PMID:Molecular diagnosis of genital HPV DNA types by polymerase chain reaction and sensitivity-standardized filter in situ hybridization in randomly sampled cohorts of Singapore women. 169 60

Infection with intracellular protozoan parasites such as Plasmodium, Leishmania and Trypanosoma cruzi induces a strong antibody response against proteins containing tandem repeats, suggesting that these repetitive epitopes may camouflage vulnerable parasite antigens from a 'protective' immune response. We tested this theory by immunoscreening a cDNA expression library of African trypanosomes, extracellular parasites that evade their hosts' immune response by antigenic variation, and found that the most frequently detected trypanosome protein contains more than 40 tandem copies of a 24-amino acid repeat with a consensus sequence of A-M-E-D-E-L-D-S-L-R-A-L-N-E-Q-Y-E-A-L-Q-R-T-N-A (net charge = -4). This protein is encoded on an mRNA of more than 20 kb and has slight sequence similarities with cytoskeletal, intermediate filament proteins in other organisms. Thus, protozoan proteins with tandemly repeating epitopes do not exist solely to divert the humoral immune response; they have other specific physiological functions for the parasites and affect the overall parasite-host interaction in unknown and perhaps different ways.
Mol Biochem Parasitol 1991 Sep
PMID:African trypanosomes express an immunogenic protein with a repeating epitope of 24 amino acids. 172 7

Infection with larval trematodes has been shown to inhibit several snail-host defences, including hemocyte phagocytosis, cytotoxicity, motility, and adherence. Certain plasma factors which mediate snail defence responses, and which may be produced by host hemocytes, also appear to be altered by these parasites. In this study we present protocols for the isolation of 2 proteins from larval Schistosoma mansoni excretory-secretory (ES) products and detail the effects of these components on Biomphalaria glabrata hemocyte protein synthetic/secretory (S/S) activity. Schistosome ES proteins, separated with a combination of membrane ultrafiltration, size exclusion, and ion exchange chromatography, were tested for their in vitro effect on cultured snail hemocytes, in the presence and absence of homologous plasma. A high-molecular-weight ultrafiltration fraction of parasite ES products (H30), in combination with plasma, was found to differentially affect susceptible (M-line) and resistant (10-R2) snail hemocytes. Secretion of metabolically labeled polypeptides by M-line cells was inhibited significantly while the S/S response of 10-R2 hemocyte polypeptides was not affected. In the absence of homologous plasma, little or no differential affect of ES polypeptides on hemocyte S/S activity was seen. Much of the inhibitory activity of H30 was attributable to a partially purified fraction, Peak I (PkI), of ES products. Evidence suggests that, in its native state, PkI is a high-molecular-weight protein aggregate comprising subunits of approximately 22-24 kDa. Thus, PkI, in the presence of homologous plasma components, is a potential mediator of schistosome-induced suppression of polypeptide synthesis or secretion in hemocytes of susceptible snails. In combination with other parasite and host factors, PkI may be involved in the host-parasite interaction which leads to the state of susceptibility or resistance found in our strains of B. glabrata.
Mol Biochem Parasitol 1991 Nov
PMID:Isolation and functional characterization of snail hemocyte-modulating polypeptide from primary sporocysts of Schistosoma mansoni. 177 50

Primary cultures of epithelial cells from adult rat tracheas were maintained in vitro on collagen matrices and were exposed to a murine retrovirus vector expressing the E. coli beta-galactosidase gene. Infection was carried out on cells grown as monolayers under medium and on cells grown on raised platforms. Cells maintained at an air-medium interface were highly susceptible to infection with the vector, showing an efficiency of infection of 20-25%, compared with an efficiency of less than 1% for cells grown under medium. Infected beta-galactosidase-expressing cells were seeded into denuded tracheas and were capable of partially repopulating the denuded tracheas grafted subcutaneously into host rats. The susceptibility of these cells to retroviral infection suggests an approach to the treatment of some pulmonary genetic disorders such as cystic fibrosis.
Somat Cell Mol Genet 1991 Mar
PMID:Gene transfer into rat airway epithelial cells using retroviral vectors. 184 20

In this study, we have constructed retroviral vectors expressing the interleukin-7 (IL-7) cDNA and have used infection with these retroviruses to express this cytokine endogenously in an IL-7-dependent pre-B-cell line. Infection with IL-7 retroviruses, but not with a control retrovirus, resulted in the conversion of the cells to IL-7 independence. The frequency at which this occurred, together with data on vector expression levels, indicated that secondary events were required for factor independence in this system. Southern analysis showed that the IL-7-dependent clones harbored unrearranged copies of the vector proviruses. The factor-independent cells produced variable quantities of IL-7 as measured by an IL-7-specific bioassay, and their proliferation could be substantially inhibited by a neutralizing antibody directed against IL-7, indicating that a classical autocrine-mechanism was responsible for their transformation. These IL-7-independent cells were tumorigenic, in contrast to the parental IL-7-dependent cells or those infected with a control vector. These results showed that IL-7 could participate in the malignant transformation of pre-B cells. However, neither of two Abelson murine leukemia virus (A-MuLV)-transformed pre-B-cell lines expressed detectable IL-7 mRNA, at a level of sensitivity corresponding to less than one molecule of mRNA per cell. Moreover, the proliferation of the A-MuLV transformants was unaffected by addition of the IL-7 antisera under conditions in which parallel experiments with IL-7 virus-infected cells resulted in greater than 70% growth inhibition. Thus, transformation of pre-B cells by A-MuLV was not associated with a demonstrable autocrine loop of IL-7 synthesis. These results show that IL-7 can participate in the malignant transformation of pre-B cells and suggest studies aimed at assessing the role of autocrine production of IL-7 in the generation of human leukemias and lymphomas.
Mol Cell Biol 1991 Mar
PMID:Interleukin-7 retroviruses transform pre-B cells by an autocrine mechanism not evident in Abelson murine. 199 10

Infection of mice with the cestode Taenia taeniaeformis exhibits several important features common to other cestode infections, including the ability to vaccinate with crude antigen mixtures. Partial purification of the protective oncosphere antigens has been reported with a cutout from deoxycholate (DOC) acrylamide gels; this cutout was called fraction II (FII), and comprises approximately 10% of total DOC-soluble oncosphere antigen. Western blots of DOC gels probed with anti-FII antisera revealed a series of 3-5 discrete bands within the FII region. Further fractionation of the FII antigens on DOC gels was impractical due to limitations in supply of oncospheres, so a cDNA library was constructed from 150 ng of oncosphere mRNA and screened with alpha-FII antisera. Two distinct clone families were identified, oncA and oncB. Antibodies affinity-purified on either of two representative members, oncA1 and oncB1, recognised all the FII bands. Individual FII bands excised from a DOC gel resolved into an overlapping series of molecules when re-run on SDS-PAGE, indicating that each FII band consisted of several polypeptides of differing molecular weight. Immunoprecipitates resolved on SDS-PAGE revealed that alpha-FII recognised 3 major oncosphere antigens, of 62, 34 and 25 kDa; antisera against oncB precipitated both the 34- and 25-kDa antigens, whereas alpha-oncA antisera precipitated the 62-kDa antigen. We conclude that oncA and oncB encode the major antigens in the FII complex. The 62-kDa antigen encoded by oncA1 was the only common antigen precipitated by anti-FII and two other antisera raised against different protective extracts, suggesting that it may be a protective component in all three. Southern blot results indicate that oncA and oncB are distinct genes present at low copy number in the genome. Evidence is also presented suggesting that some cestode mRNAs, including oncA, may use variant polyadenylation signals.
Mol Biochem Parasitol 1991 Mar
PMID:Molecular cloning of Taenia taeniaeformis oncosphere antigen genes. 205 33

Infection of mice with Leishmania donovani resulted in decreased activities of several liver enzymes involved in the metabolism of xenobiotics. Microsomal membranes from infected livers contained reduced amounts of cytochromes P450 and b5 and NADPH-cytochrome P450 reductase. Several cytochrome P450 isoenzymes (P450-PB1, P450-PB3, P450-PCN and P450-UT1) and P450-mediated reactions (aminopyrine demethylase, aniline hydroxylase, benzphentamine demethylase and ethoxycoumarin deethylase) were affected similarly. The metabolism of two carcinogens (nitrosodimethylamine and 7,12-dimethylbenz[a]anthracene) by liver microsomal membrane preparations was also reduced. Leishmania infection caused an increase of cytosolic epoxide hydrolase and microsomal epoxide hydrolase and NADH-cytochrome b5 reductase were unaffected. The results suggest that Leishmania-infected animals are likely to have altered responses to exogenous toxins compared to uninfected animals.
Mol Biochem Parasitol 1990 Jun
PMID:Changes in hepatic xenobiotic-metabolising enzymes in mouse liver following infection with Leishmania donovani. 211 55

We isolated a full-length cDNA for apoplastic (extracellular or cell wall-bound) beta-fructosidase (invertase), determined its nucleotide sequence, and used it as a probe to measure changes in mRNA as a result of wounding of carrot storage roots and infection of carrot plants with the bacterial pathogen Erwinia carotovora. The derived amino acid sequence of extracellular beta-fructosidase shows that it is a basic protein (pl 9.9) with a signal sequence for entry into the endoplasmic reticulum and a propeptide at the N terminus that is not present in the mature protein. Amino acid sequence comparison with yeast and bacterial invertases shows that the overall homology is only about 28%, but that there are short conserved motifs, one of which is at the active site. Maturing carrot storage roots contain barely detectable levels of mRNA for extracellular beta-fructosidase and these levels rise slowly but dramatically after wounding with maximal expression after 12 hours. Infection of roots and leaves of carrot plants with E. carotovora results in a very fast increase in the mRNA levels with maximal expression after 1 hour. These results indicate that apoplastic beta-fructosidase is probably a new and hitherto unrecognized pathogenesis-related protein [Van Loon, L.C. (1985). Plant Mol. Biol. 4, 111-116]. Suspension-cultured carrot cells contain high levels of mRNA for extracellular beta-fructosidase and these levels remain the same whether the cells are grown on sucrose, glucose, or fructose.
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PMID:cDNA cloning of carrot extracellular beta-fructosidase and its expression in response to wounding and bacterial infection. 215 10

The role of v-Ha-ras oncogene in tumorigenesis in an in vitro/in vivo model system was studied by investigating the expression of the Ha-ras gene, gap junctional intercellular communication, and tumorigenicity as endpoints. Infection of a Fischer 344 rat liver epithelial cell line (WB 344) with a retrovirus containing the v-Ha-ras oncogene resulted in altered cell morphology and decreased contact sensitivity. Gap junctional intercellular communication in v-Ha-ras infected WB cells (WBHa-ras), assessed by fluorescence redistribution after photobleaching (FRAP), microinjection/dye transfer, and scrape-loading/dye transfer techniques, was markedly decreased compared with the level in control WB cells. Injection of 10(7) WBHa-ras cells into the portal vein of male F344 rats caused multiple focal hepatic lesions within 1 and 2 wk, merging to large invading tumors after 3 and 4 wk. Examination of the methylation pattern of the Ha-ras gene in WBHa-ras and control WB cells showed that the infected Ha-ras gene was relatively hypomethylated in comparison to the normal cellular Ha-ras gene, indicating a greater potential for expression. There was an increased level of Ha-ras mRNA in hepatomas as compared with both adjacent nontumor liver tissue and liver tissue obtained from normal animals. Three cell lines derived from three different primary hepatic tumors induced by an injection of WBHa-ras cells in a F344 rat displayed similar growth characteristics, levels of gap junctional communication, and methylation patterns as the original WBHa-ras cells. The results of these studies have established a strong positive correlation between expression of the Ha-ras oncogene, reduced gap junctional intercellular communication, decreased contact sensitivity, and tumorigenicity of the v-Ha-ras-infected rat liver epithelial cells.
Mol Carcinog 1990
PMID:Infection of rat liver epithelial cells with v-Ha-ras: correlation between oncogene expression, gap junctional communication, and tumorigenicity. 234 86


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