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K C Gupta

Publications and source records attributed to K C Gupta.

At least 109 records · Page 6Linked to original sources
PubMed1981

Synthesis of capped and uncapped methylated oligonucleotides by the virion transcriptase of spring viremia of carp virus, a rhabdovirus.

Capped and uncapped methylated oligonucleotides, five and six nucleotides in length, were synthesized in vitro in spring viremia of carp virus transcription reaction mixtures containing ATP + CTP, ATP + CTP + GTP, or ATP + CTP + UTP, but not in any other combinations of two or three ribonucleoside triphosphates. The oligonucleotides that have been characterized are consistent with the structures: m7GpppAmpNpCpNpN, GpppAmpNpCpNpN, pppAmpNpCpNpN, and ppAmpNpCpNpN--i.e., similar to those of the termini of transcripts made in complete reaction mixtures. Because both capped and uncapped methylated oligonucleotides were synthesized, it can be concluded that methylation of the penultimate nucleotide can precede capping and methylation of the capping nucleotide. Our results also indicate that capping and methylation are processes that can take place prior to mRNA chain completion.

Methylation↗
PubMed1981

Stimulation of transcription by S-adenosyl-L-homocysteine and virion-encapsidated methyl donor in spring viraemia of carp virus.

S-Adenosyl-L-methionine (SAM), a methyl donor, and its analogue S-adenyl-L-homocysteine (SAH), an inhibitor of methylation, stimulate the activity of spring viraemia of carp virus (SVCV) virion transcriptase. The stimulation observed for SVCV is analogous to that observed previously (Furuichi, 1974, 1978) for a totally unrelated virus, cytoplasmic polyhedrosis virus (CPV). In the absence of exogenous SAM, RNA with 5'-methylated termini (presumptive GpppAmpAp) was produced, indicating that SVCV has an endogenous methyl donor. Significantly less methylated termini were produced when SVCV nucleocapsids were used to prime in vitro transcription reactions, suggesting that the majority of the endogenous methyl donor is not associated with the nucleocapsid. Partial removal of endogenous methyl donor by preparing nucleocapsids did not have any effect on the degree of stimulation by exogenous SAM or SAH. We conclude from this study that SAH has two effects on SVCV transcription, inhibition of methylation and stimulation of transcription.

Animals↗
PubMed1981

Tolerability of ibuprofen and flurbiprofen in G-6-PD deficient subjects: in vitro study.

1 A 'GSH (reduced glutathione) stability test' which consists of incubating blood samples with acetylphenylhydrazine and other test drugs and measuring GSH level before and after incubation, was carried out. 2 Application of this test to the blood of eight normal volunteers and twelve known G-6-PD deficient persons demonstrated that acetylphenylhydrazine and primaquine produced a significant decrease in GSH levels in G-6-PD deficient red cells compared to the reduction seen in normal red cells incubated with these drugs. No such change was observed with aspirin, ibuprofen and flurbiprofen. 3 The results of this in vitro study seem to indicate that ibuprofen and flurbiprofen are relatively innocuous in G-6-PD deficient individuals.

Erythrocytes↗
PubMed1980

Flurbiprofen in the treatment of primary dysmenorrhoea.

1 In a double-blind crossover study, flurbiprofen produced marked relief of pain which was significantly more than with aspirin and placebo in patients suffering from primary dysmenorrhoea. In contrast, there was no significant difference between the relief of pain obtained with aspirin and placebo. 2 The clinician's overall assessment of efficacy also indicated that flurbiprofen produced better response as compared to aspirin and placebo in these patients with dysmenorrhoea. 3 Both flurbiprofen and aspirin did not produce any apparent adverse effects on blood loss during the menstrual period. 4 In conclusion, the analgesic effect of flurbiprofen seen in this trial establishes the therapeutic usefulness of the drug in the treatment of primary dysmenorrhoea.

Adolescent↗
PubMed1980

Isolation, characterization, and biological properties of a tuberculin-active peptidoglycan isolated from the culture filtrate of Mycobacterium tuberculosis.

A water-soluble tuberculin-active peptidoglycan (TAPG) with a molecular weight of ca. 28,000 to 30,000 was isolated from the culture filtrate of Mycobacterium tuberculosis. TAPG was approximately four to five times more potent than tuberculin purified protein derivative S in guinea pigs sensitized with M. tuberculosis or M. bovis (freeze-dried BCG). It showed little or no cross-reactivity at a dose of 0.1 to 0.4 microgram in guinea pigs sensitized with M. kansasii, M. scrofulaceum, M. intracellulare, or M. avium. TAPG did not show any adjuvant activity when injected in guinea pigs in a water-in-oil emulsion containing ovalbumin. TAPG, in Freund incomplete adjuvant, proved to be an effective immunogen for inducing delayed hypersensitivity in guinea pigs. Chemical analysis of TAPG showed that it contains proline, glutamic acid, alanine, diaminopimelic acid, tyrosine, threonine, glucosamine, and the reducing sugars, arabinose and galactose. In immunoelectrophoretic studies with reference M. tuberculosis H37Rv antiserum, TAPG did not show any precipitin bands.

Adjuvants, Immunologic↗
PubMed1980

Alternate capping mechanisms for transcription of spring viremia of carp virus: evidence for independent mRNA initiation.

Two alternate mechanisms of mRNA capping for spring viremia of carp virus have been observed. Under normal reaction conditions, a ppG residue of the capping GTP is transferred to a pA moiety of the 5' termini of mRNA transcripts. However, in reaction conditions where GppNHp is used instead of GTP, an alternate capping mechanism occurs whereby a pG residue of the capping GTP is transferred to a ppA moiety of the transcripts. The first mechanism is identical to that described previously for vesicular stomatitis virus (G. Abraham, D. P. Rhodes, and A. K. Banerjee, Nature [London] 255:37-40, 1975; A. K. Banerjee, S. A. Moyer, and D. P. Rhodes, Virology 61:547-558, 1974), and thus appears to be a conserved function during the evolution of rhabdoviruses. The alternate mechanism of capping indicates not only that capping can take place by two procedures, but also that the substrate termini have di- or triphosphate 5' ends, indicating that they are probably independently initiated. An analog of ATP, AppNHp, has been found to completely inhibit the initiation of transcription by spring viremia of carp virus, suggesting that a cleavage between the beta and gamma phosphates of ATP is essential for the initiation of transcription. However, in the presence of GppNHp, uncapped (ppAp and pppAp), capped (GpppAp), and capped methylated (m7GpppAmpAp and GpppAmpAp) transcripts are detected. Size analyses of oligodeoxythymidylic acid-cellulose-bound transcripts resolved by formamide gel electrophoresis demonstrated that full-size mRNA transcripts are synthesized as well as larger RNA species. The presence of GppNHp and S-adenosylhomocysteine in reaction mixtures did not have any effect on the type of unmethylated transcription products. Our results favor a transcription model postulated previously (D. H. L. Bishop, in H. Fraenkel-Conrat and R. R. Wagner, ed., Comprehensive Virology, vol. 10, Plenum Press, New York, 1977; D. H. L. Bishop and A. Flamand, in D. C. Burke and W. C. Russell, ed., Control Processes in Virus Multiplication, Cambridge University Press, Cambridge, 1975; D. H. L. Bishop and M. S. Smith, in D. Nayak, ed., The Molecular Biology of Animal Viruses, Marcel Dekker, New York, 1977; P. Roy and D. H. L. Bishop, J. Virol. 11:487-501, 1973) in which mRNA synthesis is initiated independently; they do not support a model for transcripts being synthesized by plus-strand cleavage (A. K. Banerjee, G. Abraham, and R. J. Colonno, J. Gen. Virol. 34:1-8, 1977; A. K. Banerjee, R. J. Colonno, D. Testa, and M. T. Franze-Fernandez, in B. M. J. Mahy and R. D. Barry, ed., Negative Strand Viruses and the Host Cells, Academic Press, London, 1978).

Journal Article↗
PubMed1980

Plasma levels of trimethoprim and sulfonamide after administration of trimethoprim-sulfamethoxazole and trimethoprim-sulfamoxole.

In a cross-over study with ten healthy volunteers, the plasma levels of trimethoprim (TMP) and sulfonamides were compared using orally given trimethoprim-sulfamethoxazole (TMP-SMX: Septra) and trimethoprim-sulfamoxole (TMP-SMO: Supristol) in recommended doses. The dosage schedule for TMP-SMX was 2 tablets every 12 h for nine doses, and for TMP-SMO it was 2 tablets as in the first dose, followed by 1 tablet every 12 h for eight more doses. Serial plasma levels of TMP and sulfonamides after the first dose of each of the two products showed no significant differences. However, after the ninth dose of each product, the paired t test revealed significantly higher levels of TMP and sulfonamides after TMP-SMX as compared with TMP-SMO.

Adult↗
PubMed1979

5'-terminal sequences of spring viremia of carp virus RNA synthesized in vitro.

Sequence analyses have been undertaken on the 5' termini of the RNA species synthesized in vitro at 22 degrees C by Spring viremia of carp virion (SVCV)-associated transcriptase by using virus grown in mammalian BHK-21 cells. SVCV product RNA was synthesized in the absence or presence of low (0.56 muM) or high (0.8 mM) concentrations of added S-adenosyl-l-methionine (SAM). Two major sequences obtained in the absence (or in low concentrations) of SAM have been shown to be GpppAp and GpppAmpAp(C). A minor sequence detected when a low concentration of [(3)H]SAM was added to reaction mixtures was 7mGpppAmpAp. Larger quantities of the 7mGpppAmpAp(C) sequence, in addition to the GpppAmpAp(C) sequence, were obtained when high concentrations of SAM were used, and under these conditions no GpppAp sequences were detected. It has further been shown that with low concentrations of [(3)H]SAM the principle in vitro methylation of adenosine in SVCV product RNA occurred at the 2'-O-ribose position; no methylation at the N(6)-adenosine position and no internal product RNA methylation were detected. Comparison of the SVCV results to the published data on the 5'-terminal structures of the in vitro or in vivo mRNA species of vesicular stomatitis virus Indiana and vesicular stomatitis virus New Jersey suggests that the 5' sequences of transcript RNA of different rhabdoviruses may have been conserved.

Journal Article↗
PubMed1979

Lack of enhanced purine biosynthesis in HGPRT- and Lesch-Nyhan cells.

The rate of de novo purine biosynthesis was measured in a series of hypoxanthine guanine phosphoribosyl transferase deficient (HGPRT-) cells from a variety of sources, including human Lesch-Nyhan cells. Under optimum growth conditions, no enhanced purine biosynthesis was detected (in contrast to previous reports). An 'elevated' level of de novo purine biosynthesis could be detected in mutants following starvation for glutamine. However, this was the result of depression of purine biosynthesis in normal cells, with a resulting artifactual overproduction in mutants.

Animals↗
PubMed1978

The locus and cytoarchitecture of the projection areas of the olfactory bulb in Macaca mulatta.

A study was made of the normal and experimental anatomy of the olfactory system of the young adult male rhesus monkey. The cytoarchitecture of the central olfactory areas was studied with cell and fiber stains, while the extent and pattern of the projections of the olfactory bulb were determined by the Fink-Heimer and autoradiographic methods. The brain of one animal that had sustained damage to the olfactory bulb two days prior to sacrifice, and of one that had a transection of the olfactory tract ten days prior to sacrifice, were processed with the Fink-Heimer technique. The first of these and four others received injections of 3H-proline or 3H-leucine into the olfactory bulb, and following a survival period of 18 hours, or 2, 4, 12, or 20 days, their brains were processed with the autoradiographic technique. The results were the same for both experimental methods and for all survival periods. The projections of the olfactory bulb in this microsmatic animal are entirely ipsilateral. All of the structures that receive direct olfactory afferents have a laminar organization except for the anterior olfactory nucleus, which is laminated only in its anterior, peduncular, portion. While the olfactory bulb projects to the entire extent and depth of the anterior olfactory nucleus, the olfactory afferents of all other structures are confined to layer IA of the plexiform layer. These structures are: all divisions of the olfactory tubercle; the frontal and temporal prepiriform cortices; the oral, medial, and dorsal divisions of the superficial amygdaloid nucleus; and polar and anterior entorhinal cortex. The rhesus monkey does not have a recognizable accessory olfactory bulb, and no projections were seen to one of its targets, the nucleus of the stria terminalis. Also, no projections were seen to the taenia tecta or the ventral division of the superficial amygdaloid nucleus. With these exceptions, the projections of the olfactory bulb in the rhesus monkey are similar to those in macrosmatic species.

Afferent Pathways↗
PubMed1978

Regulation of de novo purine biosynthesis in normal and 8-azaguanine-resistant Chinese hamster cells.

Azaguanine-resistant mutants of Chinese hamster ovary cells were isolated following mutagenesis with ICR-17OG. Of the eight mutant isolates examined, only one, Ag-5 had detectable hypoxanthine(guanine)phosphoribosyltransferase activity. Under normal conditions of growth, de novo purine biosynthesis in the mutants was not significantly different from wild type. However, when the cultures were starved for glutamine over a 2 h period before measuring 5'phosphoribosyl formylglycinamide (a relative measure of de novo purine biosynthesis), elevated levels of 5'-phosphoribosyl formylglycinamide accumulated in some of the mutants, and decreased levels in wild type and Ag-5. The level of purine biosynthesis could be related to the levels of glutamine in the pregrowth medium. The rate of purine biosynthesis correlated with 5-phosphoribosyl pyrophosphate levels, which were enhanced in the mutant (Ag-C) following the starvation period. No alterations were found in levels of 5-phosphoribosyl pyrophosphate synthetase or glutamine synthetase. The extent of feedback inhibition was normal in both mutant and wild type cells. These data suggest that the hypoxanthine (guanine) phosphoribosyltransferase locus is a regulatory gene.

Azaguanine↗
PubMed1978

alpha-Amanithin-resistant mutants of Chinese hamster ovary (CHO) cells.

Spontaneous and EMS-induced alpha-amanitin-resistant CHO cells have been isolated and characterized. DNA-dependent RNA polymerase II in cell-free extracts from a mutant (ARM-1) was partially resistant to alpha-amanitin. Growing mutants for several generations in the presence or absence of alpha-amanitin did not change the pattern of inhibition. The mutants grew with a lag following transfer to medium with or without alpha-amanitin. The mutants have an altered RNA polymerase II, and possibly an altered cell membrane.

Amanitins↗