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Biomedical subjects

R Gupta

Publications and source records attributed to R Gupta.

At least 829 records · Page 46Linked to original sources
PubMed1982

Nigeran production in some Aspergillus and Penicillium species.

Thirteen additional members belonging to genera Aspergillus and Penicillium were found to be nigeran producers. Nigeran content was found to increase under carbon and nitrogen depletion and metal toxicity. Among the three metal ions--copper, iron and magnesium--copper was found to have the greatest effect in increasing nigeran content. Nigeran production varies from strain to strain and the amount is greatly influenced by environmental conditions.

Aspergillus↗
PubMed1982

Archaebacterial tRNA contains 1-methylinosine at residue 57 in T psi C-loop.

1-Methylinosine was isolated from unfractionated tRNAs of Sulfolobus acidocaldarius and Halobacterium volcani. The structure of 1-methylinosine was characterized by ultraviolet absorption and mass spectral analysis. 1-Methylinosine found in these archaebacterial tRNAs was located at residue 57 in T psi C-loop, indicating that the presence of 1-methylinosine is characteristic of archaebacteria.

Bacteria↗
PubMed1981

Secondary structure model for 23S ribosomal RNA.

A secondary structure model for 23S ribosomal RNA has been constructed on the basis of comparative sequence data, including the complete sequences from E. coli. Bacillus stearothermophilis, human and mouse mitochondria and several partial sequences. The model has been tested extensively with single strand-specific chemical and enzymatic probes. Long range base-paired interactions organize the molecule into six major structural domains containing over 100 individual helices in all. Regions containing the sites of interaction with several ribosomal proteins and 5S RNA have been located. Segments of the 23S RNA structure corresponding to eucaryotic 5.8S and 25 RNA have been identified, and base paired interactions in the model suggest how they are attached to 28S RNA. Functionally important regions, including possible sites of contact with 30S ribosomal subunits, the peptidyl transferase center and locations of intervening sequences in various organisms are discussed. Models for molecular 'switching' of RNA molecules based on coaxial stacking of helices are presented, including a scheme for tRNA-23S RNA interaction.

Animals↗
PubMed1981

Are archaebacteria merely derived 'prokaryotes'?

The archaebacteria are a group of prokaryotes which seem as distinct from the true bacteria (eubacteria) as they are from eukaryotes. The evidence on which this conclusion rests is of two types: genotypic (quantitative)--that is, comparative sequence studies, and phenotypic (qualitative)--that is, differences in various organismal characteristics. The differences between archaebacteria and true bacteria are so great, both quantitatively and qualitatively, that the two bacterial groups should be considered as representing separate primary lines of descent, each tracing directly back to the universal ancestor. Furthermore, this ancestor itself seems not to be a prokaryote; rather it was a far simpler type of organism, one properly called a progenote. If this is true, the discovery of archaebacteria marks a major advance in the biologist's attempts to understand the basis for the evolution of the cell.

Archaea↗
PubMed1981

Fertility decline and differences in less-developed countries: an anthropological microstudy of some communities of West Bengal, India and Upper Khumbu, Nepal.

The role of socioeconomic and other cultural factors as determinants of fertility change has been widely discussed, with some scholars emphasising an inverse relation between socioeconomic development and fertility, others suggesting that no such relation necessarily exists, and yet others indicating that by using data from various sources it is possible to "prove" that a given country's crude birth rate has declined, remained unchanged or increased. Demographic data are presented on age-sex structure, completed and total fertility rates, and age specific fertility rates by age cohorts of women, from several small, anthropological population units of West Bengal, India and Upper Khumbu, Nepal, exposed to various physical and cultural environmental stresses. The data show that fertility has declined in most of the populations/subpopulations studied and that the decline may, deductively, be attributed to economic development via greater family planning practices.

Adolescent↗
PubMed1980

Secondary structure model for bacterial 16S ribosomal RNA: phylogenetic, enzymatic and chemical evidence.

We have derived a secondary structure model for 16S ribosomal RNA on the basis of comparative sequence analysis, chemical modification studies and nuclease susceptibility data. Nucleotide sequences of the E. coli and B. brevis 16S rRNA chains, and of RNAse T1 oligomer catalogs from 16S rRNAs of over 100 species of eubacteria were used for phylogenetic comparison. Chemical modification of G by glyoxal, A by m-chloroperbenzoic acid and C by bisulfite in naked 16S rRNA, and G by kethoxal in active and inactive 30S ribosomal subunits was taken as an indication of single stranded structure. Further support for the structure was obtained from susceptibility to RNases A and T1. These three approaches are in excellent agreement. The structure contains fifty helical elements organized into four major domains, in which 46 percent of the nucleotides of 16S rRNA are involved in base pairing. Phylogenetic comparison shows that highly conserved sequences are found principally in unpaired regions of the molecule. No knots are created by the structure.

Bacillus↗
PubMed1980

In vivo and in vitro effects of lithium on granulopoiesis in human neutropenic disorders.

Studies have been cazrried out to determine the in vivo and in vitro effects of lithium carbonate in various neutropenic disorders. Addition of lithium to culture of bone marrow from patients with a variety of neutropenic disorders and ANLL in which normal or elevated serum and/or urinary CSA levels were present did not enhance granulocyte colony formation. Administration of lithium carbonate to patients with Felty's syndrome, in which serum and urinary CSA levels are reduced, enhanced peripheral blood neutrophil levels and serum and urinary CSA values. Lithium administration appears to be most beneficial in neutropenic patients in whom it can be demonstrated that CSA production is reduced.

Acute Disease↗
PubMed1980

Neuroleptanalgesia in otorhinolaryngology.

NEUROLEPTANALGESIA is described for its use in the management of otolaryngologic cases undergoing elective surgery. 100 cases have been reviewed extensively. The advantages and possible problems are outlined. It seems to be a highly satisfactory alternative to conventional general anesthetic techniques for most ear, nose and throat procedures and operations, where quiescence rather than anesthesia is required. The absence of direct myocardial depression and a marked decrease in operative and post-operative morbidity constitute the principal advantages.

Adolescent↗