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S K Banerjee

Publications and source records attributed to S K Banerjee.

At least 91 records · Page 5Linked to original sources
PubMed1988

Comparison of ATPase activities and heavy chains of rabbit atrial and thyrotoxic ventricular myosin subfragment-1.

Subfragment-1 of rabbit atrial and thyrotoxic ventricular myosin (V1 isomyosin) has been prepared and purified by DEAE-cellulose column chromatography. Pyrophosphate-polyacrylamide gel electrophoretic patterns and column chromatographic profile of the atrial subfragment differ from those of thyrotoxic ventricular myosin subfragment-1. On the other hand, Ca2+, Mg2+ and actin-activated ATPase activities of these subfragments are identical. Comparison of the peptide mapping by limited proteolysis in the presence of sodium dodecyl sulfate of the heavy and the light subunits of these subfragments reveals that the patterns for the heavy chain peptides of these subfragments are substantially similar but their light chain peptide patterns differ. The results suggest that the enzymatic and structural similarities that have been recognized between these isoenzymes using intact myosin hold true for the myosin subfragment-1. The differences between these subfragments are due to the differences in the light chains associated with them.

Animals↗
PubMed1988

Frequency and spectrum of mutations produced by a single cis-syn thymine-thymine cyclobutane dimer in a single-stranded vector.

We have constructed a single-stranded vector that contains a uniquely located cis-syn T-T cyclobutane dimer by ligating a synthetic oligomer containing this UV photoproduct into M13mp7 viral DNA linearized with EcoRI. In the absence of SOS induction, transfection of a uvrA6 mutant of Escherichia coli with this vector gave very few progeny plaques, and the data imply that a single dimer blocks replication in at least 99.5% of the molecules. In vitro photoreactivation completely abolished this inhibition. Transfection of cells irradiated with UV at 4 J.m-2 to induce the SOS response gave 27% of the number of plaques found with a dimer-free control. Nucleotide sequence analysis of 529 progeny phage showed that translesion synthesis was usually accurate: the normal sequence was found in 93% of them. Where mutations occurred, all were targeted single-nucleotide substitutions, with approximately 90% being targeted at the 3' nucleotide of the lesion: of a total of 26 mutations, 15 were 3' T----A, 8 were 3' T----C, and 3 were 5' T----C. No T----G mutations were found. In addition to these results with the normal construct, data were also obtained from vectors in which the M13mp7 cloning site, which forms a hairpin in single-stranded DNA, was present 4 nucleotides on the 3' side of the T-T dimer. These hairpin-containing vectors gave a very similar mutation frequency (8% versus 7%) but altered mutation spectrum: all 12 mutations detected were 3' T----A transversions, a difference from the previous set of data that is significant (P = 0.03).

Base Sequence↗
PubMed1988

Nuclear thyroid hormone receptors in rabbit heart: reduced triiodothyronine binding in atrium compared with ventricle.

Radiolabeled triiodothyronine (T3) binding to isolated nuclei was measured to compare the binding characteristics of the nuclear receptors in rabbit ventricular and atrial muscle cells. Scatchard analysis of the binding data yielded a maximum binding capacity of 170 +/- 20 fmol per mg DNA and apparent dissociation constant of 525 +/- 100 pM for ventricular nuclei. The binding capacity and the dissociation constant for the atrial muscle cell nuclei were 55 +/- 10 fmol per mg DNA and 500 +/- 75 pM, respectively. The results suggest that the binding capacity for T3 receptor in the atrium is considerably lower than that found in the ventricle. The reduced binding capacity of the T3 receptor in the atrium might reflect differences in the nuclear T3 receptors between ventricle and atrium.

Animals↗
PubMed1988

An automated approach to characterize, in simple kinetic terms, the generation and inactivation of thrombin and the interaction of fibrinogen with thrombin.

Here, we used a fully automated, computer-directed centrifugal analyzer (which permitted simultaneous turbidimetry and calculation of results) and purified thrombin, fibrinogen, and various inhibitors to study clot formation. The Km and Vm for these reactions were useful in detecting and partly characterizing anticoagulants. We also explored the generation and inactivation of thrombin, using the two-stage prothrombin time and antithrombin activity tests. The amount of thrombin instantaneously generated and inactivated was monitored under artificially created pathological conditions. The pseudo-first-order rate constant for thrombin generation and inactivation and the instantaneous concentration of enzymatically active and inactive thrombin were used in the characterization of these conditions. We believe this approach is suitable for routine clinical use.

Algorithms↗
PubMed1987

DNA damage by 5-nitro-2-furylacrylic acid, a nitrofuran derivative.

5-Nitro-2-furylacrylic acid (5-NFA) caused dose dependent inhibition of growth of Escherichia coli K-12 strain AB 2480 (uvr-, rec-), the 37% (D37) and 10% (D10) survival doses being 1.0 microgram/ml.h and 1.75 micrograms/ml.h, respectively. Although much higher doses of drug were required to achieve comparable inhibition of growth of E. coli strain 1157 (repair proficient), significant filamentation of these cells was produced by treatment with 1.0 microgram/ml 5-NFA for 4 hr. Ultraviolet absorption data and thermal chromatography through hydroxyapatite (HAP) column revealed that 5-NFA treatment of E. coli strain AB 2480 produced more than 80% of DNA reversibly bihelical due to the formation of interstrand cross-links and the initial part of the reaction obeyed a first order relation. 5-NFA also produced dose-dependent increase of prophage induction in E. coli strain GY 5027: envA, uvrB, ampA1, strA (lambda). The implications of the action of 5-NFA on DNA in relation to the induction of 'SOS' functions and carcinogenesis were discussed.

Acrylates↗
PubMed1987

Lipid profiles of conidia of Aspergillus niger and a fatty acid auxotroph.

Conidial lipids of the wild-type (V35) Aspergillus niger and its unsaturated fatty acid auxotroph (UFA2) were compared. The wild type contained lower levels (7.6%) of phospholipids and higher levels (28.4%) of glycolipids than the mutant (16.5 and 22.2%, respectively). Oleic (33.4%), linoleic (22.5%), palmitic (12.8%), stearic (7.4%), and linolenic (6.2%) were the main fatty acids of the wild type (V35). The mutant grew only in the presence of unsaturated fatty acid having at least one delta 9cis double bond, and its conidial fatty acid profile was influenced by the exogenous acid. Analyses of the fatty acids of UFA2 grown in the presence of different fatty acid supplements support the original view that the mutant is defective in delta 9-desaturase activity.

Aspergillus niger↗
PubMed1987

Effect of amiodarone on rat heart myosin isoenzymes.

The effects of amiodarone on heart weight, production of 14C-CO2 from labelled glucose, myosin ATPase activity, and myosin isoenzyme patterns were determined by comparing control and amiodarone-treated male Wistar rats. Since it has been suggested that amiodarone may interfere with thyroid hormone action on the heart, similar experiments were also carried out in hypothyroid and amiodarone-plus-triiodothyronine(T3)-treated rats, and the data were compared to those obtained in amiodarone-treated rats. Amiodarone treatment for 6 weeks resulted in lower heart weight, decreased atrial production of 14C-CO2 from labelled glucose, decreased myosin Ca-ATPase activity, and preferential synthesis of V3 isomyosin. These effects were similar to those observed in hypothyroid rats but were lesser in magnitude. T3 treatment of amiodarone-treated rats reversed all the changes induced by amiodarone. Serum thyroxine (T4) was higher in amiodarone-treated than in control rats, while serum T3 was similar. Serum T3 was higher in the amiodarone-plus-T3 than in the amiodarone-treated group. These results show that 1) amiodarone-induced changes resemble hypothyroidism with respect to cardiac myosin expression and atrial CO2 production, 2) amiodarone causes hypothyroid-like changes despite normal serum T3 and increased serum T4, and 3) T3 reverses the effects of amiodarone. These data support the hypothesis that amiodarone inhibits the action of thyroid hormone on the heart.

Adenosine Triphosphatases↗
PubMed1986

A fully automated immuno-turbidimetric determination of fibrin(ogen) degradation products.

A fully automated procedure for the determination of fibrin(ogen) degradation products was developed using the I. L. Multistat Centrifugal Analyzer (MCA). The assay is based on the turbidometric measurement of the interaction between antibodies to human fibrinogen and defibrinogenated specimens. The method allows, with high reproducibility, for the accurate quantitation of degradation products between 10 and 160 micrograms/ml. A comparative study of 100 normal and abnormal patient samples revealed an excellent correlation with the semi-quantitative manual procedure. The method can be adapted to existing automated coagulation procedures and can become part of coagulation panels.

Antibodies↗
PubMed1985

A fully automated method for clot based coagulation panels using an MCA Multistat Centrifugal Analyzer.

Small modifications of the commercially available software of the I.L. Multistat Centrifugal Analyzer (MCA) enabled us to evaluate clot based prothrombin times (PT), activated partial thromboplastin times (APTT) and thrombin times (TT) simultaneously within one run. This imparted a great deal of flexibility to this procedure in that batches and/or panels of clot based and other types of turbidimetric tests can be performed concurrently in any combination. The PT and TT by this turbidimetric procedure correlated very well with those of the Fibrometer in normal specimens as well as in a wide variety of coagulation defects. The turbidimetric APTT procedure, however, often produced clotting times longer than those achieved with the Fibrometer. The discrepancy between the Fibrometer and turbidimetric APTT procedures was shown to be the consequence of greater sensitivity of the latter to detect low concentrations of heparin, elevated fibrinogen split products and mild factor deficiencies. The available clot based procedures are suitable for use in detecting specific factor deficiencies and the presence of coagulation inhibitors.

Autoanalysis↗
PubMed1985

An unsaturated fatty acid mutant of Aspergillus niger with partially defective delta 9-desaturase.

The wild-type Aspergillus niger (V35) does not require fatty acids for growth. Four unsaturated fatty acid auxotrophs designated as UFA1, UFA2, UFA3, and UFA4 have been produced from this organism by treating the conidia of the wild-type strain with a mutagen, N-methyl-N'-nitro-N-nitrosoguanidine, followed by isolation on media containing monounsaturated fatty acids and the nonionic detergent, Brij 58. Optimal growth of the mutants comparable with that of the wild type was achieved with medium supplemented with C16 or C18 unsaturated fatty acids containing at least one cis double bond at the delta 9 position. Some other fatty acids (18:1 delta 11 cis and 16:1 delta 9 trans) support growth to some extent. The mutants do not grow at all in the presence of saturated fatty acids. Fatty acid analyses of the mutant, UFA2, grown in the presence of different fatty acid supplements reveal that it may be defective in a desaturase system. Experiments with unlabeled and [1-14C]palmitoyl-CoA have shown that the microsomes of the mutant (UFA2) contain a partially defective delta 9-desaturase system.

Aspergillus niger↗
PubMed1985

Lipid profiles of Aspergillus niger and its unsaturated fatty acid auxotroph, UFA2.

A comparative study of the mycelial lipid composition of a wild strain (V35) and one unsaturated fatty acid auxotroph (UFA2) of Aspergillus niger has been performed. The lipid composition of both strains are qualitatively the same but quantitatively different. All the strains contain the following phospholipids: cardiolipin, phosphatidylethanolamine, phosphatidylcholine, lysophosphatidylethanolamine, lysophosphatidylcholine, and phosphatidylserine; and triglycerides, diglycerides, monoglycerides, ergosterol, and sterol esters as the neutral lipids; mono- and di-galactosyl diglyceride as the major glycolipids along with small amounts of the corresponding mannose analogs. Phosphatidylethanolamine and phosphatidylcholine constitute the bulk of the phospholipids. The mutant (UFA2) contains a higher level of glycerides and lower levels of sterol (both free and esterified form), phospholipids, and glycolipids than the wild type. Aspergillus niger contains C16 to C18 saturated and unsaturated fatty acids. Small amounts of long-chain (C20 to C24) and short-chain (C10 to C14) saturated and unsaturated acids are also present. Linoleic, oleic, and palmitic are the major acids, stearic and linolenic acids being minor ones. UFA2 grows only in the presence of unsaturated fatty acid (C16 or C18) and accumulates a higher concentration of supplemented acid which influences its fatty acid profile.

Aspergillus niger↗
PubMed1984

Comparative evaluation of contraceptive efficacy of norethisterone oenanthate (200 mg) injectable contraceptive given every two or three monthly. Indian Council of Medical Research Task Force on Hormonal Contraception.

A total of 2388 subjects, 1181 for 60 +/- 5-day and 1207 for 90 +/- 5-day treatment regimen with norethisterone oenanthate (NET OEN) 200 mg injection, were observed for 24 months, constituting 28,513 woman-months. This clinical trial represents the largest clinical trial undertaken on NET OEN. The observations indicated that NET OEN given at 60 +/- 5-day intervals provides adequate contraceptive protection. However, as compared to the published studies elsewhere, higher method failures were seen during the first six months of NET OEN usage, when all women were receiving the drug at 60 +/- 5-day intervals. The reasons for this discrepant observation in the present study cannot be explained. The higher method failures reported with 90 +/- 5-day regimen were mainly during the third month following the injection, suggesting reduced contraceptive efficacy of the drug during this period. Thin build women (body weight less than or equal to 40 kg) were at higher risk of involuntary pregnancy. Disrupted menstrual pattern was the major reason for discontinuation ranging between 42-43 per 100 users at the end of 24 months. Amongst these, amenorrhoea was the commonest reason for discontinuation. No change in blood pressure was observed during contraceptive usage. The majority of NET OEN users did not show any change in body weight. The overall continuation rates with NET OEN were lower than those observed in similar conditions with Cu-T 200 mm2 IUCD.

Adult↗
PubMed1984

Nucleotide-induced changes in the heat capacity of beef cardiac myosin.

The heat of reaction of ATP with beef cardiac myosin has been determined in a flow microcalorimeter at two different temperatures. The reaction heat obtained by extrapolation to infinite flow rate is interpreted to be the heat of formation of the steady-state set of myosin-nucleotide complexes. The large temperature dependence of this heat, an apparent change in heat capacity, could be caused by an isomerization between two myosin conformations. The enthalpies and heat capacities of binding of ADP, AMP, and pyrophosphate have also been measured and are discussed in terms of this model.

Adenosine Diphosphate↗