One of the early purine analogs showing antineoplastic activity. It functions as an antimetabolite and is easily incorporated into ribonucleic acids.
A serovar of the bacterial species LEPTOSPIRA INTERROGANS, whose primary host is RATS.
6-(Methylthio)-9-beta-D-ribofuranosylpurine. An analog of inosine with a methylthio group replacing the hydroxyl group in the 6-position.
A triazine nucleoside used as an antineoplastic antimetabolite. It interferes with pyrimidine biosynthesis thereby preventing formation of cellular nucleic acids. As the triacetate, it is also effective as an antipsoriatic.
Purine bases related to hypoxanthine, an intermediate product of uric acid synthesis and a breakdown product of adenine catabolism.
Drugs that are chemically similar to naturally occurring metabolites, but differ enough to interfere with normal metabolic pathways. (From AMA Drug Evaluations Annual, 1994, p2033)
Enzymes of the transferase class that catalyze the transfer of a pentose group from one compound to another.
A series of heterocyclic compounds that are variously substituted in nature and are known also as purine bases. They include ADENINE and GUANINE, constituents of nucleic acids, as well as many alkaloids such as CAFFEINE and THEOPHYLLINE. Uric acid is the metabolic end product of purine metabolism.
A genus of aerobic, helical spirochetes, some species of which are pathogenic, others free-living or saprophytic.
The study of the origin, nature, properties, and actions of drugs and their effects on living organisms.

Characterization of the mutational profile of (+)-7R,8S-dihydroxy-9S, 10R-epoxy-7,8,9,10-tetrahydrobenzo[a]pyrene at the hypoxanthine (guanine) phosphoribosyltransferase gene in repair-deficient Chinese hamster V-H1 cells. (1/71)

Earlier studies have shown that the profile of mutations induced by (+)-7R,8S-dihydroxy-9S,10R-epoxy-7,8,9,10-tetrahydrobenzo[a]pyrene (+)-BPDE at the hypoxanthine (guanine) phosphoribosyltransferase (hprt) gene of Chinese hamster V79 cells was dependent on the concentration of (+)-BPDE. In the present study, we examined the effect of the concentration of (+)-BPDE on its mutational profile at the hprt gene in repair-deficient V-H1 cells (a derivative of V79 cells) to explore the role of DNA repair in the dose-dependent mutational profile of (+)-BPDE. Independent hprt mutant clones were isolated after exposing V-H1 cells to dimethylsulfoxide (DMSO) or to low (4-6 nM; 95% cell survival) or high (40-48 nM; 31% cell survival) concentrations of (+)-BPDE in DMSO. The mutation frequencies for the DMSO control and for the low and high concentration groups were 0.1, 2.1 and 32.9 mutant colonies/10(5) survivors, respectively. The profile of mutations at the hprt gene was characterized for 148 (+)-BPDE-induced mutant clones and the results from the present study were compared with those obtained earlier with V79 cells. The data indicated that: (i) V-H1 cells were approximately 9-fold more sensitive to the cytotoxic effects of (+)-BPDE than V79 cells; (ii) the mutation frequency in V-H1 cells was similar to that observed in V79 cells following exposure to similar concentrations of (+)-BPDE; (iii) (+)-BPDE-induced mutations at guanine on the transcribed strand of the hprt gene were common in V-H1 cells but were extraordinarily rare in V79 cells; (iv) (+)-BPDE-induced mutations at adenine on the transcribed strand of the hprt gene were common in both V-H1 and V79 cells; (v) although exposure of V79 cells to different doses of (+)-BPDE resulted in a dose-dependent mutational profile at the hprt gene, this was not observed in V-H1 cells. Our observations indicate a defect in the transcription-coupled repair of (+)-BPDE-DNA adducts in V-H1 cells and that the repair activity deficient in V-H1 cells is essential for the dose-dependent mutational profile observed with (+)-BPDE in V79 cells.  (+info)

Mutability of different genetic loci in mammalian cells by metabolically activated carcinogenic polycyclic hydrocarbons. (2/71)

The relationship between carcinogenesis and mutagenesis in mammalian cells has been determined with 10 polycyclic hydrocarbons with different degrees of carcinogenicity. Mutagenesis was determined in Chinese hamster cells with genetic markers that affect the surface membrane, nucleic-acid synthesis, and protein synthesis. The mutations were characterized by resistance to ouabain, 8-azaguanine, and temperature. Mutagenesis by the carcinogens required metabolic activation and this was provided by the presence of lethally irradiated metabolizing cells. The degree of carcinogenicity was related to the degree of mutagenicity for all three genetic markers. The most potent carcinogen, 7,12-dimethylbenz[a]anthracene, gave the highest mutagenicity and mutagenicity was obtained with 0.01 mug/ml. Treatment of the cells with aminophylline, which increases polycyclic hydrocarbon metabolism, increased mutagenesis by the carcinogens. It is suggested that such an experimental system with these and other mammalian cells should be useful as a sensitive assay for hazardous environmental chemicals.  (+info)

Genetic modification of substrate specificity of hypoxanthine phosphoribosyltransferase in Salmonella typhimurium. (3/71)

Salmonella typhimurium strain GP660 (proAB-gpt deletion, purE) lacks guanine phosphoribosyltransferase and hence cannot utilize guanine as a purine source and is resistant to inhibition by 8-azaguanine. Strain GP660 was mutagenized and a derivative strain (GP36) was isolated for utilization of guanine and hypoxanthine, but not xanthine, as purine sources. This alteration was designated sug. The strain was then sensitive to inhibition by 8-azaguanine. Column chromatographic analysis revealed the altered phosphoribosyltransferase peaks for both hypoxanthine and guanine to be located together, in the same position as hypoxanthine phosphoribosyltransferase (hpt gene product) of the wild-type strain. Genetic analysis showed the sug mutation to be allelic with hpt. Therefore sug represented a modification of the substrate specificity of the hpt gene product.  (+info)

Requirement for cell dispersion prior to selection of induced azaguanine-resistant colonies of Chinese hamster cells. (4/71)

With V79 Chinese hamster cell cultures treated with a mutagen, the maximum frequency of colonies resistant to 8-azaguanine (AZG) was attained when the cells were dispersed after a suitable expression time before adding the selection medium. V79-4 cells were exposed to 500 muM MMS, 7 muM AFAA, or 10 muM MNNG and allowed to multiply before being reseeded at 4 times 10-4 cells/60 mm dish and selected with 10 mu-g/ml AZG. Maximum frequencies of 4 times 10-5, 4 times 10-4, and 2.4 times 10-3 were obtained about 100, 130, and 200 hrs after exposure to MMS, AFAA, and MNNG, respectively. The maximum frequencies following MMS or MNNG treatments were about 10-fold greater than those obtained when induction and selection of AZG-resistant colonies were performed in the same culture dish. The reseeding of treated cells eliminated the possibility of metabolic cooperation within mosaic colonies of wild-type and mutant cells and achieved expression of the induced changes before intercolony crossfeeding reduced the frequency of resistant colonies. - AZG-resistant colonies were selected in medium containing dialyzed fetal bovine serum, and the selection medium replacement were necessary for consistent achievement of background frequencies of resistant colonies near 10-6. Reconstruction experiments with AZG-resistant V79 lines showed that the efficiency of recovery of resistant cells in the selection medium was constant over a range of 0-20 colonies observed/dish. A mixed population of V79 and AZG-resistant cells was also correctly analyzed by the procedure used in mutagenesis studies.  (+info)

Mechanisms of action of 6-thioguanine, 6-mercaptopurine, and 8-azaguanine. (5/71)

The effects of 6-thioguanine on purine biosynthesis and cell viability have been examined in H.Ep. 2 cells grown in culture. Toxicity is not reversed by aminoimidazolecarboxamide, suggesting that inhibition of purine biosynthesis de novo is not the sole mechanism of toxicity. Also, 6-(methylmercapto)purine ribonucleoside, a potent inhibitor of purine biosynthesis de novo, produces more marked reductions in cellular pools of purines than does 6-thioguanine without killing cells. There is no apparent inhibition by 6-thioguanosine 5'-monophosphate of other enzymes leading to the synthesis of guanosine 5'-triphosphate as determined in whole cells by measurements of radioactive hypoxanthine or guanine incorporation. Inhibition of DNA synthesis by 1 mM thymidine protects cells from 6-mercaptopurine or 6-thioguanine but fails to protect cells from 8-azaguanine toxicity. On the other hand, inhibition of RNA synthesis by 6-azauridine plus deoxycytidine protects cells against 8-azaguanine but does not protect against 6-thioguanine or 6-mercaptopurine toxicity. In agreement with the in vitro data, arabinosylcytosine (a potent inhibitor of DNA synthesis) fails to protect mice against 8-azaguanine but has previously been shown to protect mice from 6-mercaptopurine or 6-thioguanine toxicity. The results support the hypotheses of others that incorporation into DNA (as 6-thioguanine nucleotide) is a mechanism of toxicity for these thiopurines, whereas 8-azaguanine is toxic due to its incorporation into RNA.  (+info)

Mutant enrichment in the colonial alga, Eudorina elegans. (6/71)

An enrichment procedure has been developed that results in at least a 200 X increase in mutation frequency in the colonial alga, Eudorina elegans. A period of nitrogen starvation followed by treatment with 8-azaguanine results in the death of wild-type cells and the maintenance of mutants. N'-nitro-N-nitro-soguanidine-induced acetate, p-aminobenzoic acid and reduced nitrogen requiring mutants have been isolated by this procedure.  (+info)

Characterisation of methionine adenosyltransferase from Mycobacterium smegmatis and M. tuberculosis. (7/71)

BACKGROUND: Tuberculosis remains a serious world-wide health threat which requires the characterisation of novel drug targets for the development of future antimycobacterials. One of the key obstacles in the definition of new targets is the large variety of metabolic alterations that occur between cells in the active growth and chronic/dormant phases of tuberculosis. The ideal biochemical target should be active in both growth phases. Methionine adenosyltransferase, which catalyses the formation of S-adenosylmethionine from methionine and ATP, is involved in polyamine biosynthesis during active growth and is also required for the methylation and cyclopropylation of mycolipids necessary for survival in the chronic phase. RESULTS: The gene encoding methionine adenosyltransferase has been cloned from Mycobacterium tuberculosis and the model organism M. smegmatis. Both enzymes retained all amino acids known to be involved in catalysing the reaction. While the M. smegmatis enzyme could be functionally expressed, the M. tuberculosis homologue was insoluble and inactive under a large variety of expression conditions. For the M. smegmatis enzyme, the Vmax for S-adenosylmethionine formation was 1.30 micromol/min/mg protein and the Km for methionine and ATP was 288 microM and 76 microM respectively. In addition, the enzyme was competitively inhibited by 8-azaguanine and azathioprine with a Ki of 4.7 mM and 3.7 mM respectively. Azathioprine inhibited the in vitro growth of M. smegmatis with a minimal inhibitory concentration (MIC) of 500 microM, while the MIC for 8-azaguanine was >1.0 mM. CONCLUSION: The methionine adenosyltransferase from both organisms had a primary structure very similar those previously characterised in other prokaryotic and eukaryotic organisms. The kinetic properties of the M. smegmatis enzyme were also similar to known prokaryotic methionine adenosyltransferases. Inhibition of the enzyme by 8-azaguanine and azathioprine provides a starting point for the synthesis of higher affinity purine-based inhibitors.  (+info)

Inhibition of protein syntheses during meiosis and its bearing on intracellular regulation. (8/71)

Several parameters of meiosis have been studied in cultured anthers of Trillium erectum. The accessibility of labeled substrates to meiotic cells and the fate of these substrates in relation to meiotic stage have been determined. Evidence has been adduced for the synthesis of RNA and protein during the meiotic cycle well after chromosome duplication. The effect of interfering with systems directly or indirectly connected with protein formation has been studied by means of chloramphenicol, 8-azaguanine, 5-methyltryptophan, and ethionine. Administration of these reagents at different intervals in the cycle elicits correspondingly different responses thereby indicating a periodicity in the activities of different systems. The following processes have been shown to be affected in these experiments: chromosome segregation, chromosome morphology, cytokinesis, wall synthesis, and enzyme appearance. The possibility of experimentally altering the normal sequence of events has also been shown.  (+info)

Azaguanine * Azaguanine-8 * 8-Azaguanine * Azan * AZG * B-28 * Guanazol * Guanazolo * NSC-749 * Pathocidin * Pathocidine * SF- ... 8-Azaguanine was the first purine analogue discovered to inhibit experimental tumors in mice. * Sources: "Azaguanine - Compound ... "Azaguanine[permanent dead link]" on the Merck Index "Azaguanine" (CID 8646) on PubChem (CS1 errors: missing periodical, ... 8-Azaguanine is a purine analog with the chemical formula C4H4N6O. It has been widely studied for its biological activity. It ...
... produces blasticidin S and pathocidin-(8-azaguanine). List of Streptomyces species LPSN bacterio.net ...
8-azaguanine, and 1-4,dimethanesulfonyloxybutane on an experimental brain tumor". Ann. of the N.Y. Acad. Sci. 60: 2273-282. ...
Resistance to 8-azaguanine in S. typhimurium - Similar to Ames test, but instead of reverse mutation, it checks for forward ... Such systems include the HPRT assay for resistance to 8-azaguanine or 6-thioguanine, and ouabain-resistance (OUA) assay. Rat ... mutation that confer resistance to 8-Azaguanine in a histidine revertant strain. Escherichia coli systems - Both forward and ...
Chantrenne H, Devreux S., Effects of 8-azaguanine on the synthesis of protein and nucleic acids in Bacillus cereus, Nature. ...
Growth is inhibited by 8-azaguanine at 225 µg/mL or 2,6-diaminopurine (10 µg/mL) and copper sulfate. It contains serovars from ...
... and 8-azaguanine. Thus, selection with one of the latter two drugs, followed by HAT medium, will yield revertant colonies. HAT ...
... azaguanine MeSH D03.438.759.758.399.475 - hypoxanthine MeSH D03.438.759.758.824 - xanthines MeSH D03.438.759.758.824.175 - ...
... and guanine as well as azaguanine carbocyclic derivatives (IV) Vince lactam is also an intermediate in the synthesis of various ...
... produces 8-azaguanine and blasticidin S. List of Streptomyces species LPSN bacterio.net Straininfo of ...
... an Azerbaijani cargo airline AZA-GUANINE RESISTANT, a transporter of purines This disambiguation page lists articles associated ...
LL: I dont think we ever looked into that, except, you know, like 8-azaguanine, which was so good in mice . . . it just didnt ... But all the others we did, including 6-MP, in children . . . but 8-azaguanine, which was so good in mice, just didnt work in ... But one of them that worked very good was methotrexate . . . again, aminopterin, plus guanazole . . . 8-azaguanine. But ...
Azaguanine Preferred Term Term UI T004028. Date01/01/1999. LexicalTag NON. ThesaurusID NLM (1966). ... Azaguanine Preferred Concept UI. M0002061. Registry Number. Q150359I72. Related Numbers. 134-58-7. Scope Note. One of the early ... 8-Azaguanine Term UI T004027. Date11/29/1982. LexicalTag NON. ThesaurusID ... 8-Azaguanine Guanazolo Pharm Action. Antimetabolites, Antineoplastic. Registry Number. Q150359I72. Related Numbers. 134-58-7. ...
Azaguanine - Preferred Concept UI. M0002061. Scope note. One of the early purine analogs showing antineoplastic activity. It ...
Azaguanine D3.438.759.758.399.454.300 D3.633.100.759.758.399.454.300 Azasteroids D4.808.925.100 D4.210.500.925.100 Azathioprine ...
Azaguanine Preferred Term Term UI T004028. Date01/01/1999. LexicalTag NON. ThesaurusID NLM (1966). ... Azaguanine Preferred Concept UI. M0002061. Registry Number. Q150359I72. Related Numbers. 134-58-7. Scope Note. One of the early ... 8-Azaguanine Term UI T004027. Date11/29/1982. LexicalTag NON. ThesaurusID ... 8-Azaguanine Guanazolo Pharm Action. Antimetabolites, Antineoplastic. Registry Number. Q150359I72. Related Numbers. 134-58-7. ...
... azaguanine,noun,E0011535,yes de,deazaguanosine,noun,E0512164,azaguanosine,noun,E0409227,yes de,deazainosine,noun,E0527777, ...
Results we have observed showed that 8-azaguanine induced a decrease in cell viability in a dose, time and cell type dependent ... Cell line samples were incubated, some without different azaguanine concentration and others with, ranging from 10 to 100muM. ... These preliminary results suggest that 8-azaguanine stimulates CD26 expression which may be related to cellular sensitivity to ... CD26/DPPIV expression and 8-azaguanine response in T-acute lymphoblastic leukaemia cell lines in culture. ...
C1306 0H43101T0J 7-ETHYL-10-HYDROXYCAMPTOTHECIN C61618 7BU5H4V94A 7-HYDROXYSTAUROSPORINE C1271 Q150359I72 8-AZAGUANINE C28788 ...
PMID- 14428007 TI - 8-Azaguanine inhibition of haemoglobin synthesis in de-embryonated chick blastoderm. PMID- 14428009 TI - ...
5-bromouracil and 8-azaguanine, are incorporated into DNA in vivo,-" it was of interest to determine whether our enzyme system ...
AND PE AZAGUANINE ENVIRONMENTAL POLLUTANTS, NOXAE, AND PE AZASERINE ENVIRONMENTAL POLLUTANTS, NOXAE, AND PE AZATHIOPRINE ... NOXAE AZAGUANINE NOXAE AZASERINE NOXAE AZATHIOPRINE NOXAE AZAURIDINE NOXAE AZOXYMETHANE NOXAE BLEOMYCIN NOXAE BROMODEOXYURIDINE ... ANTINEOPLASTIC AGENTS AZAGUANINE ANTINEOPLASTIC AGENTS AZASERINE ANTINEOPLASTIC AGENTS AZATHIOPRINE ANTINEOPLASTIC AGENTS ... ANTIMETABOLITES AZAGUANINE ANTIMETABOLITES AZASERINE ANTIMETABOLITES AZATHIOPRINE ANTIMETABOLITES AZAURIDINE ANTIMETABOLITES ...
... azaguanine,noun,E0011535,yes de,deazaguanosine,noun,E0512164,azaguanosine,noun,E0409227,yes de,deazainosine,noun,E0527777, ...
Azaguanine D3.438.759.758.399.454.300 D3.633.100.759.758.399.454.300 Azasteroids D4.808.925.100 D4.210.500.925.100 Azathioprine ...
8-azaguanine, hypoxanthine-aminopterin-thymidine medium (HAT/HT), Delbuccos Modified Eagle Medium (DMEM), bovine serum albumin ...
Differential requirement for de novo RNA synthesis in the starved-refed rat; inhibition of the overshoot by 8-azaguanine after ...
Azaguanine / pharmacology Actions. * Search in PubMed * Search in MeSH * Add to Search ...
The mutagenic activities of several phthalate esters have been evaluated in an 8-azaguanine resistance assay in Salmonella ... in the azaguanine resistance assay. The data suggest a need for further investigation of the mutagenic potential of these ...
Azaguanine - Preferred Concept UI. M0002061. Scope note. One of the early purine analogs showing antineoplastic activity. It ...
... carchesium dasyclados pyrrhonota spasmolytic ethylsuccinate htatip myelodysplasia s632 methacryloxypropoxy s630 azaguanine ...
b) Mice - induction of melanin synthesis in albino mice skin by DNA from pigmented mice; transfer of IUDR and azaguanine ...
Strain Eri-1(T) grew in Korthofs medium at both 13 and 30 °C, and also in the presence of 8-azaguanine. 16S rRNA gene-based ...
Azaguanine D3.438.759.758.399.454.300 D3.633.100.759.758.399.454.300 Azasteroids D4.808.925.100 D4.210.500.925.100 Azathioprine ...
Azaguanine D3.438.759.758.399.454.300 D3.633.100.759.758.399.454.300 Azasteroids D4.808.925.100 D4.210.500.925.100 Azathioprine ...
Azaguanine D3.438.759.758.399.454.300 D3.633.100.759.758.399.454.300 Azasteroids D4.808.925.100 D4.210.500.925.100 Azathioprine ...
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