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Biomedical subjects

B Chatterjee

Publications and source records attributed to B Chatterjee.

At least 91 records · Page 5Linked to original sources
PubMed1979

Superinduction of alpha 2u globulin by actinomycin D: evidence for drug-mediated increase in alpha 2u mRNA.

Actinomycin D, an inhibitor of DNA-dependent RNA synthesis, increased the hepatic concentration of alpha 2u globulin, an androgen-inducible protein in the rat. Spayed female rats with a marginally induced state of alpha 2u synthesis showed an approximately 5-fold increase in hepatic alpha 2u globulin within 3-6 hr after treatment with actinomycin D. Initial treatment of these animals with 5 alpha-dihydrotestosterone, followed by actinomycin D, resulted within 2-3 hr in a more than 2-fold increase in hepatic alpha 2u globulin compared to animals treated with the androgen alone. In spite of inhibition of hepatic synthesis of poly(A)-containing RNA to less than 25% of control, superinduction with actinomycin D resulted in a parallel increase in the translatable mRNA for alpha 2u globulin. These results showing increase in both alpha 2u globulin and its translatable mRNA after superinduction with actinomycin D support the concept of post-transcriptional repression of alpha2u synthesis.

Alpha-Globulins↗
PubMed1977

Body size and work output.

The relationship between work output and anthropometric, biochemical, and socioeconomic varables was studied in 57 male industrial workers engaged in the production of detonator fuses. These workers were studied for 3 months and their daily work output was carefully measured. Work output was measured in terms of the number of fuses produced per day. Clinical and biochemical examination indicated that their current nutritional status was adequate. Among the parameters studied only body weight, height, and lean body weight were significantly correlated with work output. Body weight and lean body weight were significantly correlated (P less than 0.001) with work output even after removing the influence of height by partial correlation. Total daily work output was significantly higher (P less than 0.01) in those with higher body weight and lean body weight. The rate of work was also higher in the higher body weight group

Adult↗
PubMed1976

Protein synthesis in rabbit reticulocytes. Characteristics of mRNA (AUG codon)-dependent binding of Met-tRNAfMet to 40 S and 80 S ribosomes.

The characteristics of Met-tRNAfMet binding to ribosomes (40 S and 80 S) were studied using a two-stage assay method (Gupta, N.K., Chatterjee, B. and Majumdar, A. (1975) Biochem. Biophys. Res. Commun. 65, 797) and the complexes formed were analyzed either by Millipore filtration or by sucrose density gradient centrifugation. The results are summarized as follows: (a) with both assay methods, Met-tRNAfMet binding to 40 S ribosomes was entirely dependent upon addition of a partially purified mixture of initiation factors and AUG codon; (b) this binding occurred over a wide Mg2+ concentration range; significant binding was observed even at 20 mM Mg2+; (c) upon addition of 60 S ribosomes, a significant part of Met-tRNAfMet bound to 40 S ribosomes was transferred to 80 S complex. This transfer reaction had a sharp Mg2+ optimum around 2 mM. Met-tRNAfMet-80 S-AUG complex thus formed was active in Met-puromycin synthesis; (d) Met-tRNAfMet deacylase present in crude 0.5 M KCl ribosomal wash is a potent inhibitor of the binding reaction as it deacylates Met-tRNAfMet in the Met-tRNAfMet-40 S-AUG complex; (e) glutaraldehyde (0.5%) degrades Met-tRNAfMet-40 S-AUG complex but increases the background binding of Met-tRNAfMet to 40 S ribosomes in the absence of AUG codon; (f) polynucleotides containing uracil and adenosine are strong inhibitors of Met-tRNAfMet binding to 40 S ribosomes. The order of inhibitory activities of the polynucleotides tested was as follows: poly(rU)-poly(rA) (2:1) greater than poly(rU)-poly(rA) (1:1) greater than poly(rU) greater than poly(rA). Other RNAs tested such as poly(rC), poly(rI)-poly(rC) and phi6 bacteriophage RNA (double-stranded) were without significant effects on the Met-tRNAfMet-binding reaction.

Animals↗
PubMed1975

Protein synthesis in rabbit reticulocytes. A study of Met-tRNA f Met binding factor(s) and Met-tRNA f Met binding to ribosomes and AUG codon.

The effects of additions of Mg-2+, ribosomes, and AUG codon on the Met-tRNAf Met-initiation factor-GTP complex were studied using a Millipore filtration method (J. Biol. Chem. 248, 4500 (1973)). Upon addition of increasing concentration of Mg-2+, the Met-tRNAf Met-initiation factor-GTP complex dissociates into free Met-tRNAf Met and initiation factor (GTP), with an infection around 1.5 to 2 mM Mg-2+. The Mg-2+-induced dissociation of Met-tRNAf Met-initiation factor-GTP complex was enhanced at ice bath temperature. At 37 degrees and in the presence of 1.5 to 2mM Mg-2+, the Met-tRNAf Met-initiation factor-GTP complex catalyzes the transfer of Met-tRNAf Met to ribosomes and AUG codon. Ribosome bound Met-tRNAf Met is stable to Mg-2+ and low temperature. A Millipore filtration assay for studies of (35S)Met-tRNAf Met binding to ribosomes and Aug codon has been developed. The assay procedure is carried out in three stages. In Stage I, the Met-tRNAf Met is bound to initiation factor in the presence of GTP, AUG codon (required for Stage II reaction), and 3.7 times 10-5 M aurintricarboxylic acid. The incubation is carried out at 37 degrees for 5 min. In Stage II, ribosomes and Mg-2+ (1.5 to 2mM final concentration) are added and the incubation is continued at 37 degrees for 10 min. In Stage III, more Mg-2+ is added to make the final Mg-2+ concentration of the incubation mixture 5 mM, and the reactions are further incubated at ice bath temperature for 10 min. The reactions are then terminated by addition of excess cold wash buffer and filtered through Millipore filters. Under the standard assay conditions, the radioactivity bound to Millipore filters in the absence of ribosomes and AUG codon is markedly reduced. Addition of ribosomes alone gave a significant increase in the radioactivity bound to Millipore filters. A further 2- to 3-fold stimulation of binding of (35S)Met-tRNAf Met to Millipore filters was observed when both ribosomes and AUG codon were added. The Met-tRNAf Met bound to ribosomes under the assay condition was reactive with puromycin. Upon DEAE-cellulose chromatography of a partially purified mixture of initiation factors (IF), Met-tRNAf Met binding activities separate into two forms, and are designated as IF-1A and IF-1B. These two forms can be distinguished by the stabilities of their respective Met-tRNAf Met-IF-1-GTP complexes to Mg-2+. The Met-tRNAf Met-IF-1A-GTP complex is distinctly more stable in the presence of Mg-2+ than Met-tRNAf Met-IF-1B-GTP complex. Continue.

Animals↗
PubMedDate not supplied

The evolutionary tangle of aging, sex, and reproduction and an experimental approach to its molecular dissection.

Exchange of genetic materials by two individual members of the same species is considered to be the origin of primitive sex. During evolution, this primitive form of molecular sex has been transformed into a complex biological function involving specialized sexual structures and multiple hormonal interactions. Development and maintenance of these reproductive structures are also dependent on hormones and hormone receptors. Furthermore, reproductive specialization in higher forms of life has led to customized species-specific rates of aging and life-span potentials that are commensurate with the reproductive needs of the particular type of organism. Because of this reproductive imposition on aging of the organism, temporal regulation of the hormone response is a significant component of the genetics of aging. We have observed a marked age-dependent alteration in the hepatic expression of the rat androgen receptor (rAR) gene. Among the large number of transcription factors that control the rAR gene, at least three appear to participate in its age-dependent regulation. Two of these are positively acting and yet/to be characterized transcription factors, while the third is a negative regulator the nuclear factor kappa B (NF-kappa B). NF-kappa B is the major trans-regulator for genes involved in the immune response, inflammation, and oxidative stress. Involvement of NF-kB in the modulation of both oxidative stress and sex function provides the first example of a common molecular link between sex and aging.

Aging↗