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Biomedical subjects

S K Bose

Publications and source records attributed to S K Bose.

At least 91 records · Page 5Linked to original sources
PubMed1981

Modulation of bacterial association to HeLa cell cultures by cell density and by chlamydial infection.

The effect of cell density on the rate of association of Escherichia coli and Staphylococcus aureus by monolayer cultures of HeLa 229 cells was investigated. Radioactively labeled bacteria were incubated with sparsely and densely plated cells. The rate of bacterial uptake was 10- to 20-fold higher in sparse cultures. Kinetic analysis of data with different multiplicities of input bacteria showed that the Km of the reaction was unaltered, whereas the Vmax was inversely related to cell density. Pretreatment of HeLa cultures with dibutyryl adenosine 3',5'-phosphate had little effect on the rate of bacterial association. The simultaneous presence of an obligately parasitic bacterium, Chlamydia trachomatis LGV434, enhanced the Vmax of association of E. coli and S. aureus. This effect was more pronounced in dense HeLa cell cultures. Heat-inactivated chlamydiae were unable to modify the association. Enhanced association persisted for at least 3 h after infection with chlamydiae.

1-Methyl-3-isobutylxanthine↗
PubMed1979

Glycolytic enzyme activities in malignant cells grown in vitro and in vivo.

Cell proximity has a profound effect on the glycolytic enzyme levels observed in mammalian cells grown in vitro. Hexokinase activity generally increased with the increasing cell density of both untransformed and virus-transformed cultures. In contrast, phosphofructokinase and pyruvate kinase activities were generally elevated only in crowded cultures of transformed cells. A spontaneous experimental mouse tumor cell line (EMT6) exhibited cell crowding-dependent elevations in glycolytic enzyme levels when cultured in vitro. The glycolytic enzyme levels of experimental mouse tumors grown in vivo, on the other hand, were constant and normally less than those observed in cultured EMT6 cells.

Animals↗
PubMed1979

Deoxyribonucleic acid synthesis, cell cycle progression, and division of Chlamydia-infected HeLa 229 cells.

The fate of lymphogranuloma venereum strain Chlamydia-infected HeLa 229 cells was examined by determining the rate of deoxyribonucleic acid synthesis and the kinetics of entry into and progression through S phase and by time-lapse cinemicrography. At an input multiplicity of 5 or less, Chlamydia-infected cells showed no inhibition of host deoxyribonucleic acid synthesis or cell cycle progression. Cinemicrography showed division of inclusion-containing cells, with one or both daughters receiving chlamydial inclusions. Analysis of the family trees indicated that the generation times of infected HeLa 229 were not altered relative to those of the uninfected cells.

Cell Cycle↗
PubMed1978

Some observations on the nature of reactive groups involved in reversal of mycobacillin inhibition by sterols and lipids.

Antifungal action of di- and triacetyl derivatives of mycobacillin is not antagonised by cholesterol or lecithin which antagonise the action of its heptamethyl derivative. Considering the reactive groups of mycobacillin, the antagonism may involve the tyrosine hydroxyl groups of the antibiotic and the 3-hydroxyl group of cholesterol of the oleic acid component of lecithin having unsaturation at the 9:10 position with cis-configuration.

Antifungal Agents↗
PubMed1977

Evaluation of mycobacillin and versicolin as agricultural fungicides. III. Growth pattern and antibiotic production in soil by Aspergillus versicolor.

Soil supports the growth of a jute pathogen Colletotrichum gloeosporioides but only to a limited extent that of its antagonist Aspergillus versicolor. The growth of the sensitive pathogen is considerably checked by the antagonist in mixed soil culture although versicolin production could not be demonstrated within the limits of assay. Both the sensitive and the antagonistic organisms grow well in soil-compost medium and versicolin production by the latter is also enhanced. The antagonistic effect of Aspergillus versicolor on Colletotrichum gloeosporioides is expectedly more marked in soil-compost medium than in soil medium.

Antifungal Agents↗
PubMed1976

Evaluation of mycobacillin and versicolin as agricultural fungicides. II. Stability in soil.

The effect of paddy soils on mycobacillin and versicolin was investigated. Soil inactivated mycobacillin as determined by spectral analysis and microbiological assay. Soil can inactive mycobacillin only at or above the threshold concentration (125 approximately 130 mug per 10 mg of soil), the excess being unreacted. No new peak appears in the ultraviolet spectrum (240 approximately 300 nm) while mycobacillin is inactivated. Soil is without any effect on versicolin.

Adsorption↗
PubMed1976

In vitro and in vivo evaluation of versicolin, an antifungal antibiotic.

Versicolin is mainly active against Trichophyton rubrum. It is inactivated by serum. However, attainable blood level can be fifteen to twenty times higher than the fungicidal concentration for as long as 4 hours after a single intravenous administration of the maximum tolerable dose of 25 mg/kg body weight of mouse. It has no haemolytic activity like other polypeptide antibiotics. Skin does not show the presence of any measurable amount of the antibiotic. It is excreted through urine to the extent of 65% of the maximum tolerable dose of the antibiotic administered intravenously. Versicolin is effective against experimental infection by T. rubrum in guinea pigs at dose as low as 2.5 mg/kg body weight. The antibiotic shows no sign of subacute toxicity at these curative doses.

Animals↗