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Biomedical subjects

N Goyal

Publications and source records attributed to N Goyal.

28 records · Page 2Linked to original sources
PubMed1995

Oxidation and reduction of cytochrome c by mitochondrial enzymes of Setaria cervi.

A mitochondria-rich fraction isolated from the cuticle-hypodermis-muscle system of Setaria cervi, a bovine filarial parasite, possessed substrate-coupled cytochrome c reductases and cytochrome c oxidase in appreciable activities. All these activities were located predominantly in the membranes. NADH-coupled cytochrome c reductase was more prominent than NADPH- and succinate-coupled reductases. All the three reductases exhibited marked sensitivity to rotenone and antimycin A. Salicylhydroxamic acid strongly inhibited succinate requiring reductase and cytochrome c oxidase, but the other two reductases only mildly. Sodium azide activated the reductases but substantially inhibited the oxidase activity. Potassium cyanide activated the succinate requiring reductase but did not cause any noticeable change in the activities of pyridine nucleotide linked reductases. Anthelmintics also influenced these activities but no definite correlation could be drawn regarding their mode of action.

Animals↗
PubMed1995

Biochemical changes in heat stressed promastigotes of Leishmania donovani.

On exposing promastigotes of L. donovani (Dd-8) to 34 degrees C for 30 hr, the flagella were shed, and size was decreased with 10% viability loss. The in vitro and in vivo infectivity of two forms was more or less similar. The 45Ca2+ uptake by the transformed cells was increased as compared to normal cells. Activity of 5'-nucleotidase was increased while activity of Mg(2+)-ATPase remained same. Parasite antioxidant enzymes were also significantly altered by heat shock. There was significant increase in superoxide dismutase, glutathione reductase and glutathione peroxidase. It was accompanied by decrease in ratio of reduced glutathione to oxidized glutathione.

Animals↗
PubMed1994

Status of glutathione in lymphoid tissues of golden hamster during Leishmania donovani infection.

During Leishmania donovani infection of golden hamsters, changes in the glutathione levels of lymphoid tissues were observed. While in liver and thymus there was significant decrease in the levels of reduced and oxidised glutathione, that in spleen, bone marrow cells, peritoneal exudate cells and lymph nodes increased, indicating a role for host glutathione in establishing the infection.

Animals↗
PubMed1992

Four conserved cysteine residues are required for the DNA binding activity of nuclear factor I.

The role of Cys residues in the site-specific DNA binding activity of the nuclear factor I (NFI) family of proteins was assessed by chemical modification and site-specific mutagenesis. Treatment with the thio-specific reagent N-ethylmaleimide abolished site-specific DNA binding of all forms of NFI present in HeLa nuclear extracts. Preincubation of cell extracts with an oligonucleotide containing an NFI-binding site provided partial protection of NFI from N-ethylmaleimide inactivation. Mutations were made in the cDNA encoding a truncated form of the NFI-C/CAAT box transcription factor-1 protein, converting each of the five Cys residues in the DNA-binding domain of the protein into Ser residues. NFI-C proteins containing mutations in any of four conserved Cys residues, expressed in Escherichia coli or in vitro, did not bind to DNA. NFI-C with a mutation in a nonconserved Cys residue had normal DNA binding activity. Both this active mutant and wild-type NFI-C protein were inactivated by modification of their sulfhydryl residues with 5,5'-dithiobis(2-nitrobenzoic acid) (DTNB), and preincubation with an oligonucleotide containing an NFI-binding site gave partial protection against inactivation. After modification with DTNB, DNA binding activity was partially restored by subsequent incubation with dithiothreitol, indicating that inactivation of NFI by DTNB was reversible. These studies indicate an essential role for free sulfhydryl residues in NFI-DNA binding.

Amino Acid Sequence↗
PubMed1992

Specific receptors for beta-endorphin on mesangial cells.

beta-Endorphin is an endogenous opioid considered to be a modulator of immune injury. We studied the binding of [125I]beta-endorphin on cultured rat mesangial cells at 4 and 37 degrees C. The results were analyzed by computer program (Ligand). Incubation of rat mesangial cells with unlabeled beta-endorphin displaced [125I]beta-endorphin in a concentration-dependent manner. The binding of [125I]beta-endorphin was not affected by either opiate agonists or antagonists. Saturation studies at 37 degrees C revealed that beta-endorphin binding was time dependent. Binding studies revealed the presence of a single class of high-affinity binding sites with an apparent Kd of 15.3 nM. The number of receptor sites was calculated as 8.48 x 10(5) sites/cell. Mesangial cells exposed to beta-endorphin (10(-6) M) for 48 h showed enhanced incorporation of [3H]thymidine when compared to untreated cells (control, 23,228 +/- 2,778 cpm/well vs. beta-endorphin, 44,887 +/- 4,259 cpm/well; p less than 0.01). Our results show that mesangial cells carry a specific receptor for beta-endorphin which may be linked to proliferation of mesangial cells.

Animals↗
PubMed1991

NADH oxidase and fumarate reductase of Ancylostoma ceylanicum.

Ancylostoma ceylanicum, the hookworm parasite of cat, dog and man, was found to contain NADH and/or NADPH oxidase as well as fumarate reductase activities. Both the enzyme systems were predominantly located in the membranes of mitochondrial-rich preparations. The membranes also exhibited the presence of a reduced pyridine nucleotide transhydrogenase activity which transferred hydrogen from NADPH to NAD. Amongst respiratory inhibitors, rotenone (Site I inhibitor) markedly depressed both NADH oxidase and fumarate reductase while others, namely antimycin-A, KCN and azide, had a lesser effect.

Ancylostoma↗
PubMed1990

Mitochondrial NADH oxidase activity of Setaria cervi.

The bovine filarial parasite, Setaria cervi, has been found to contain NAD(P)H oxidase activity. The system was predominantly located in the mitochondrial membranes, with very little activity available in the soluble fraction of the organelle. The membrane preparation also exhibited the presence of a reduced pyridine nucleotide transhydrogenase which converted NADPH into NADH by transferring a hydride ion. The oxidase activity was inhibited by all the respiratory inhibitors examined, with the greatest sensitivity to rotenone, a site I-specific inhibitor. The system was also found to be susceptible to exposure to anthelmintics, amongst which levamisole proved the most effective.

Aerobiosis↗
PubMed1990

Analysis of multiple forms of nuclear factor I in human and murine cell lines.

Nuclear factor I (NFI) is a group of related site-specific DNA-binding proteins that function in adenovirus DNA replication and cellular RNA metabolism. We have measured both the levels and forms of NFI that interact with a well-characterized 26-base-pair NFI-binding site. Five different NFI-DNA complexes were seen in HeLa nuclear extracts by using a gel mobility shift (GMS) assay. In addition, at least six forms of NFI were shown to cross-link directly to DNA by using a UV cross-linking assay. The distinct GMS complexes detected were composed of different subspecies of NFI polypeptides as assayed by UV cross-linking. Different murine cell lines possessed varying levels and forms of NFI binding activity, as judged by nitrocellulose filter binding and GMS assays. The growth state of NIH 3T3 cells affected both the types of NFI-DNA complexes seen in a GMS assay and the forms of the protein detected by UV cross-linking.

Animals↗
PubMed1989

Management information system for leprosy eradication programme--an alternative information system.

For efficient monitoring of multidrug therapy programmes for leprosy both at microlevel (individual patient monitoring) as well as microlevel (programme monitoring), DANIDA decided to develop an alternative, simple and quick information system using a computer. A patient data base system was designed using dBase III Plus package. The field workers of the National Leprosy Eradication Programme were trained in transcribing data on to coded data sheets. The data of 1750 patients of six leprosy control units from the 4 MDT districts were processed and feedback reports were sent to paramedical workers and programme managers. The initial experience in the field over the past year has shown that a computerized management information system is feasible and well accepted by the field staff for the purpose of improving monitoring.

Database Management Systems↗