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Biomedical subjects

V V Modi

Publications and source records attributed to V V Modi.

At least 19 recordsLinked to original sources
PubMed1991

Degradation of isomeric monochlorobenzoates and 2,4-dichlorophenoxyacetic acid by a constructed Pseudomonas sp.

A 4-chlorobenzoate-degrading Pseudomonas sp. US1 was mated with a strain of Escherichia coli JMP 397 (harbouring the plasmid pJP4). An ex-conjugant designated Pseudomonas sp. US1 ex that could utilize all the isomeric monochlorobenzoates and 2,4-dichlorophenoxyacetate was obtained. The ex-conjugant released stoichiometric amounts of chloride when grown on these chloroaromatics as sole sources of carbon and energy.

2,4-Dichlorophenoxyacetic Acid↗
PubMed1991

Perspectives of recycling gamma irradiated sewage-sludge in agricultural applications: a study on methi (Trigonella foenum-graecum L.: leguminosae).

The effects of gamma-irradiated sludge on the growth and yield of methi (Trigonella foenum-graecum L.) in pot cultures have been studied. Gamma-irradiated sludge was found to inhibit the shoot length after 45 and 90 days of plant growth compared to plants grown in soil containing unirradiated sludge. The untreated sludge did not exhibit any detrimental effect on the shoot length of plants compared to the control. The root length of plants grown in soil supplemented with either gamma-irradiated or unirradiated sludge was found to be inhibited after 45 days of growth. However, irradiation of sludge resulted in the higher inhibition of root length of plants compared to when unirradiated sludge was used. The gamma-irradiated sludge appeared to negatively affect the physical growth parameters of the plant. The significant positive effect of gamma-irradiated sludge was observed on the biochemical growth parameters and yield of methi plants. There was a 3.5-, 1.7- and 2-fold increase in the total protein content, total soluble sugars and starch content, respectively, of plants grown in soil supplemented with gamma-irradiated sludge after 45 days of growth. The gamma-irradiated sludge did not show any detrimental effect on any of the three biochemical parameters studied, even after 90 days of plant growth. The sludge obtained from the conventional treatment process was found to be inhibitory to the protein and starch content of plants in the latter stages of plant growth. A significant increase in the yield of methi plants, after 45 as well as 90 days, grown in the presence of gamma-irradiated sludge indicates a beneficial effect of recycling of irradiated sludge for agricultural applications.

Journal Article↗
PubMed1990

Sodium selenite induced changes during ripening in post-harvest banana (Musa sapientum) fruits.

The metabolic role of selenium, if any, in plant systems has received little attention, as opposed to animal and other systems where many studies have been performed. Post-harvest banana (Musa sapientum) fruits treated with 1 mM solutions of sodium selenite show an increase in the rate of ripening. Visually, typical ripening changes in colour, aroma and tissue softness were observed to occur earlier in sodium selenite-treated fruits as compared to controls. These results were substantiated biochemically, enzymologically and physiologically, showing a strong relationship of this phenomenon with the oxidative changes.

Antioxidants↗
PubMed1989

Potential of recycling gamma-irradiated sewage sludge for use as a fertilizer: a study on chickpea (Cicer arietinum).

The effects of gamma-irradiated sludge on the growth and yield of chickpea (Cicer arietinum) in pot cultures have been studied. Compared to plants grown only in soil, root length, fresh weight and dry weight of plants grown in soil supplemented with unirradiated sludge were found to be significantly reduced. This inhibition in growth was found to be nullified when plants were grown in soil supplemented with gamma-irradiated sludge, suggesting that gamma radiation induced inactivation of toxic substance(s) in sludge. The protein content of plants grown in soil supplemented with irradiated sludge was also found to be significantly increased compared to those grown with unirradiated or no sludge, after 45 days. There was no significant effect of gamma irradiated sludge on shoot length, total soluble sugars, starch content and yield of chickpea plants. The results obtained suggest that the sludge tested, and obtained from the digester of a conventional domestic sewage treatment plant, is inhibitory to several growth parameters. Gamma irradiation of sewage resulted in removal of this inhibition. This suggests a possibility of beneficial and safe recycling of gamma-irradiated sludge for agricultural uses.

Journal Article↗
PubMed1989

Metabolism of 3-chlorobenzoate by a Pseudomonas (diff) spp.

Pseudomonas (diff) spp. was isolated from a complex petrochemical sludge, using benzoate as the sole source of carbon. The organism could metabolize 3-chlorobenzoate, releasing approximately 30% of organically bound chloride. 3-Chlorodihydrodihydroxybenzoate and 3-chlorocatechol were confirmed as pathway intermediates by mass spectral and HPLC analysis. About 3-fold higher levels of catechol 1,2-oxygenase were detected in cells grown on 3-chlorobenzoate as compared to that of benzoate. 3-Chlorocatechol inhibited the catechol 1,2-oxygenase activity, when used as assay substrate. A 15-fold purified catechol 1,2-oxygenase had a Km of 0.37 mumole and Vmax of 2.3 with 3-chlorocatechol. Catechol gave Km of 0.2 mumole and Vmax of 40, suggesting that 3-chlorocatechol is not metabolised further and hence blocks the metabolic pathway for 3-chlorobenzoate degradation. In contrast catechol 1,2-oxygenase was not inhibited by 4-chlorocatechol and probably is an intermediate for the total/complete degradation of 3-chlorobenzoate (approx. 30%).

Biodegradation, Environmental↗
PubMed1988

Effect of gamma-irradiated sludge on the growth and yield of rice (Oryza sativa L. var. GR-3).

The effects of gamma-irradiated sludge on the growth and yield of rice (Oryza sativa L. var. GR-3) in pot cultures have been studied. Compared to plants grown only in soil, shoot length, root length, fresh weight, dry weight, total proteins, total soluble sugars, starch and chlorophyll content of plants grown in soil supplemented with unirradiated or gamma-irradiated sludge were found to be significantly increased. Irradiation of sludge significantly stimulated the linear growth of shoot and root systems as well as fresh and dry weights of plants, compared to those grown in soil containing unirradiated sludge. There was also an improvement in the grain yield (weight of seed) when plants were grown in soil supplemented with irradiated sludge. The results obtained suggest that the gamma-irradiated sewage sludge can be beneficially recycled for agricultural uses.

Journal Article↗
PubMed1987

Metabolism of n-alkanes by Aspergillus japonicus.

Cells of Aspergillus japonicus could degrade n-alkanes as a sole source of carbon. One of the pathways operative during the degradative process was the terminal pathway. Electron micrographs showed that the hydrocarbons were present in the cells as microdroplets.

Alkanes↗
PubMed1987

Inactivation of bacteria in sewage sludge by gamma radiation.

The survival of certain bacterial cultures suspended in sewage sludge and exposed to gamma-radiation was studied. The inactivation patterns of most of the organisms were significantly different when irradiation was performed using sewage samples collected in the summer and monsoon seasons. The summer sample collected from the anaerobic digestor afforded significant protection to both Gram negative and Gram positive organisms. This was evident by the increase in dose required to bring about a 6 log cycle reduction in viable count of the bacterial cultures, when suspended in sewage samples instead of phosphate buffer. The observations made using monsoon digestor samples were quite different. This sewage sludge greatly enhanced inactivation by gamma-radiation in most cases. The effects of certain chemicals on the inactivation patterns of two organisms-Salmonella typhi and Shigella flexneri-were examined. Arsenate, mercury and lead salts sensitised S. typhi, while barium acetate and sodium sulphide protected this culture against gamma-radiation. In the case of Sh. flexneri, barium acetate and iodacetamide proved to be radioprotectors. The effects of some chemicals on the inactivation pattern of Sh. flexneri cells irradiated in sludge are also discussed.

Journal Article↗
PubMed1987

Microbial degradation of chlorinated aromatic compounds.

Many microorganisms are capable of utilizing anthropogenic chloroaromatics as the sole source of carbon and energy. Techniques of co-cultivation, conjugation, and in vitro cloning have been used to extend the range of haloaromatic degradation in bacteria. Employment of suitable 'degrader' strains may contribute significantly towards the removal of these compounds from the environment.

Alcaligenes↗
PubMed1986

Degradation of orcinol by Aspergillus niger.

Aspergillus niger could utilize orcinol (5-methyl-resorcinol or 3,5-dihydroxytoluene) as the sole source of carbon and energy. In the first step of catabolism A. niger hydroxylates orcinol to form 2,3,5-trihydroxytoluene. Its oxidized form, 2-hydroxy-6-methyl-1,4-benzoquinone, was also formed in the culture medium during growth of this organism. Orcinol-grown cells showed a net increase in the intracellular acetate pool, compared with glucose-grown cells. Cell-free extracts of orcinol-grown cells showed higher activity of orcinol hydroxylase, catechol 1,2-oxygenase, and isocitrate lyase than that of glucose-grown cells. Both orcinol-grown and resorcinol-grown cells exhibit similar respiratory activity on all the substrates checked.

Aspergillus niger↗
PubMed1986

Lipid peroxidation by gamma-radiation in Salmonella typhi membranes: the effect of ascorbic acid.

Lipid peroxidation in isolated membranes of Salmonella typhi occurred following gamma irradiation. The presence of the sensitizer, ascorbic acid, during irradiation resulted in a stimulation in the level of peroxidation. This enhancement of lipid damage could be prevented by the addition of the free radical scavenger sodium formate. Catalase and superoxide dismutase appeared less effective in this respect. Peroxidation in an unsaturated fatty acid and a phospholipid was also affected by gamma radiation and ascorbic acid in a manner similar to that observed in the cell membranes. The results suggest that hydroxyl radicals may be the major species responsible for the increased peroxidation effected by the sensitizer.

Ascorbic Acid↗