Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0027651 (tumor)
 685,946 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Bacterial expression of the transforming region of Moloney murine sarcoma virus, designated mos, was obtained as a fusion protein with a portion of the small tumor antigen of polyoma virus. This was accomplished by fusing the entire mos open reading frame, encoding a 41,000-dalton protein, with a plasmid that expresses a beta-galactosidase-polyoma fusion protein under lac operon control. The resulting plasmid directed synthesis of the predicted polyoma antigen-sarcoma virus fusion protein of 59,000 daltons. This protein was immunoprecipitated by an anti-polyoma tumor antigen antiserum that recognized polyoma determinants at the NH2 terminus of the hybrid protein. This protein was also immunoprecipitated by an antiserum directed against a synthetic peptide containing the 12 COOH-terminal amino acids encoded by the mos open reading frame. This work confirms the existence of a long open reading frame in the mos gene and resolves a discrepancy between different nucleotide sequences for its COOH-terminal coding region.
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PMID:Expression of transforming region of Moloney murine sarcoma virus in Escherichia coli as a fusion protein with small tumor antigen of polyoma virus. 627 95

We have constructed plasmids that direct the synthesis of the Rous sarcoma virus transforming gene (src) product (p60src) in Escherichia coli. A 203-base-pair lac promoter-operator DNA encoding the first eight amino acids of beta-galactosidase was ligated to the 5' end of the src gene from the Prague A strain of Rous sarcoma virus (PrA-RSV) which had been cloned in pBR325. Antiserum, from a tumor-bearing rabbit, directed against pp60src was used to screen bacteria containing the recombinant plasmid for a protein of approximately 60,000 daltons, and several colonies producing a protein immunologically related to pp60src were detected. Partial proteolytic cleavage analysis revealed that the src-related protein produced in bacteria is structurally similar to pp60src immunoprecipitated from PrA-RSV-infected chicken cells. Partially purified src protein from E. coli can be phosphorylated in vitro by the catalytic subunit of cAMP-dependent protein kinase. Tryptic phosphopeptide analysis demonstrated that the catalytic subunit phosphorylated a serine-containing tryptic peptide in the bacterial src protein that comigrated with the phosphoserine-containing tryptic peptide of pp60src immunoprecipitated from 32P-labeled PrA-RSV-infected chicken cells.
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PMID:Construction of plasmids for expression of Rous sarcoma virus transforming protein, p60src, in Escherichia coli. 628 67

As an approach to the study of mammalian gene expression, the promoters and translation initiation regions of the rat preproinsulin II and the simian virus 40 early genes were fused to the structural gene of Escherichia coli beta-galactosidase, a sensitive probe for gene expression. These fusions were introduced into COS-7 cells, a simian virus 40 large tumor-antigen-producing monkey kidney cell line, where they directed the synthesis of enzymatically active hybrid beta-galactosidase proteins. Conditions for transfection were varied to optimize the expression of beta-galactosidase activity in the transfected cells. The pH optimum of this activity was found to be 7.0, the same as that of native E. coli beta-galactosidase and distinct from the major lysosomal "acid" beta-galactosidase. The fused preproinsulin-beta-galactosidase was further characterized by gel electrophoresis of nondenatured cell extracts stained by a fluorogenic substrate and by immunoprecipitation and gel electrophoresis of 3H-labeled cell proteins. These results all indicate that fully active tetrameric beta-galactosidase hybrids can be produced in mammalian cells. The expression of preproinsulin-beta-galactosidase activity was measured in the presence of high glucose, insulin, dexamethasone, or epidermal growth factor but no regulatory changes were observed.
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PMID:Expression of a preproinsulin-beta-galactosidase gene fusion in mammalian cells. 631 May 64

The effect of either high-cellulose (15%) or regular-cellulose (5%) diets on fecal bacterial glycosidases was assessed in two groups of ten Wistar rats, each given an injection of 1,2-dimethylhydrazone, and in two groups of six control rats. During a 4-month period, fecal activities of bacterial beta-galactosidase and beta-acetylglucosaminidase were reduced markedly in control rats maintained on the high-cellulose diet. Enzyme differences were even more significant in rats fed high- or regular-cellulose diets and given injections of the carcinogen. This decrease in fecal bacterial enzymes induced by a high-cellulose diet was observed as early as 20 days after initiation of the diet. Lowering of bacterial beta-glycosidases by a high-cellulose diet may preserve the glycoprotein integrity of colonic cells. It may also reduce the luminal production of potential mutagens from dietary beta-glycosides in the colon. The latter has been postulated as an important mechanism in colonic tumor development.
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PMID:Influence of high dietary cellulose on fecal glycosidases in experimental rat colon carcinogenesis. 631 73

The effects of Bestatin, a low molecular weight metabolite of Streptomyces olivoreticuli on the human and mouse/rat immune system, have been studied in detail. To describe the activity of the immunomodulating dipeptide, it has been tested in vitro, ex vivo and in vivo in various experimental models. Bestatin simultaneously applied with selected antigens to mice was able to enhance the DTH response against a challenge injection of the respective antigen given into the footpad. Serum antibody levels against those antigens were uneffected. However, an increase of PFC could be found in those mice given high doses of Bestatin. On natural killer cell activity against Yac-1 tumor cells the dipeptide had no effect in low responder (DBA2/J) mice. In high responder mice (CBA/JCr), however, a significant increase of NK cell activity of spleen cells could be found, when the drug was given on day 0 or on days 0 to 3 and the test was performed on day 4. Bestatin had no effect on the generation of allogeneic cytotoxic T-lymphocytes in vivo or in vitro and even a suppressive effect on the induction of syngeneic antitumor CTL. Contrary to this suppressive effect, Bestatin increases in the popliteal lymph node assay the weights in a dose-dependent way. When mouse macrophages or human monocytes were either incubated in vitro with Bestatin or mice were treated with the dipeptide parenterally or orally and the macrophages from those mice were investigated, Bestatin induced in vitro and in vivo a dose-dependent increase in pinocytic uptake of radioactive colloidal gold. Also the oxidative metabolism was dose-dependently augmented as measured by chemiluminescence. Bestatin modulates the macrophage mediated cytotoxicity. In vitro or in vivo activated mononuclear phagocytes exhibited a dose-dependent increase in cytotoxic activity for several tumor target cells. A minimum ratio of 50:1 effector to target cells was necessary for this cytotoxic effect. A similar degree of activation was observed in macrophages from athymic nu/nu-mice or from endotoxin resistant C3H/HeJ-mice. Other parameters of macrophage activation were determined by measuring secretion of lysosomal enzymes and liberation of prostaglandins. Bestatin interacts with macrophages in vivo and in vitro by increasing their secretory activity of acid hydrolases (beta-glucuronidase, beta-galactosidase, and N-acetyl-beta-D-glucosaminidase). This release was dose- and time-dependent and not associated with any sign of cell death. Another class of mediators produced by macrophages after stimulation with Bestatin were the prostaglandins E2 and F2a.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Studies on the mechanisms of action of the immunomodulator Bestatin in various screening test systems. 638 22

A solid-phase enzyme-linked immunosorbent assay (ELISA) has been developed for detecting monoclonal antibodies binding to surface antigens expressed on viable adherent cells of tumor cell lines. This assay utilizes a sheep anti-mouse IgG to which a beta-galactosidase is linked. It is highly sensitive and permits quantification of IgG monoclonal antibody levels. In studies of monoclonal antibodies prepared against human tumors, the ELISA assay revealed the presence of antigens which were not seen using acetone-fixed cell immunofluorescence methods. This assay is safe, rapid, low cost, and gives reproducible quantitative results. As such it should prove useful to laboratories engaged in the study of antigens expressed on cell membranes.
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PMID:An enzyme-linked immunosorbent assay (ELISA) for the detection of monoclonal antibodies recognizing surface antigens expressed on viable cells. 640 27

The specific activities of five glycohydrolases of lysosomal origin (beta-N-acetylglucosaminidase, beta-glucuronidase, beta-galactosidase, alpha-mannosidase and alpha-fucosidase) were measured in different types of primary and metastatic tumors of the human nervous system. The activities of these hydrolytic enzymes in samples of tumor tissue were compared with those in the white matter of 'control' tissue. The specific activities of beta-glucuronidase and beta-N-acetylglucosaminidase were significantly higher (P less than 0.001) in each group of tumors than in normal cerebral matter. The activities of the other hydrolases were sometimes significantly increased in primary tumors, but not always. In metastatic tumors, they were also significantly higher (P less than 0.01).
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PMID:Study of some lysosomal glycohydrolases in tumors of the nervous system. 672 45

The lysosomal response of a murine macrophage-like tumor cell line (J774) during persistent infection with Coxiella burnettii was examined. By using acid phosphatase as a lysosomal marker, it was shown that phagosome-lysosome fusion occurred in J774 cells persistently infected with C. burnetii. This observation was verified using thorium dioxide, an electron-dense compound that is sequestered in secondary lysosomes. The phagolysosomes contained viable replicating rickettsiae. Spectrofluorometric analysis indicated that the phagolysosomal pH of persistently infected cells was acidic. In attempts to correlate rickettsial survival with lysosome function, the activities of several lysosomal enzymes were assayed in both infected and uninfected cells. Activities of acid phosphatase and beta-acetylglucosaminidase were not significantly altered during infection. However, infected cells appeared to display slightly higher intracellular lysozyme, beta-glucuronidase, and beta-galactosidase activities.
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PMID:Lysosomal response of a murine macrophage-like cell line persistently infected with Coxiella burnetii. 685 16

Estimation of activity of five hydrolytic enzymes was made in foru histologically different types of human meningiomas derived from surgery. The hydrolytic enzymes examined in 13 tumors included four lysosomal enzymes: beta-glucuronidase, N-acetyl-beta-D-glucosaminidase (hexosaminidase), beta-galactosidase, and acid phosphatase. The fifth enzyme studied was alkaline phosphatase. The one papillary-type meningioma examined appeared to contain generally greater activities of the lysosomal enzymes than the other tumor types. Alkaline phosphatase was decidedly greater in transitional type meningiomas. The correlation of histological types with alkaline phosphatase activity is discussed with regard to previous observations.
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PMID:Hydrolytic enzymes in meningiomal subtypes. 735 74

The activities of five hydrolytic enzymes (acid and alkaline phosphatase, hexosaminidase [N-acetyl-beta-D-glucosaminidase], beta-galactosidase, and beta-glucorinidase) were measured in reconstituted homogenates of lyophilized human brain tissue and primary and metastatic tumors. The linearity of reaction, with respect to incubation time, and optimal pH of each enzyme and in tumor tissues were comparable to those in normal brain tissue. Total enzyme activities of hexosaminidase, beta-glucuronidase, and beta-galactosidase were significantly higher in tumors than in normal cerebral white matter. The ratio of hexosaminidase activity to beta-glucuronidase activity was significantly lower for metastatic than for primary tumors or normal white matter. When histological observations do not clearly establish if a brain tumor is primary or metastatic, this ratio may help. Alteration of hydrolytic enzyme activities as demonstrated here may be indicative of "ket enzymes" that are essential for maintaining the metabolic advantages of tumors.
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PMID:Hydrolytic enzyme activities of the nervous system. 738 65


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