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Biomedical subjects

K Murugesan

Publications and source records attributed to K Murugesan.

At least 19 recordsLinked to original sources
PubMed2006

Induction of systemic resistance in Lycopersicon esculentum cv. PKM1 (tomato) against Cucumber mosaic virus by using ozone.

Studies were undertaken to evaluate ozone (O(3)) for induction of resistance against Cucumber mosaic virus in Lycopersicon esculentum cv. PKM1 (tomato) plants. Callus induced from tomato leaf explants on Murashige & Skoog's (MS) medium supplemented with benzyladenine (8.82 microM) were treated with different concentrations of ozone T(1), T(2), T(3) and for control (C), filtered air was supplied. Regeneration of shoots was obtained by culturing ozone treated calli on MS medium containing 17.3 microM benzyladenine. The frequency of regeneration of tomato plants from the callus were T(1)=79%, T(2)=61%, T(3)=42%, but for control 90% regeneration was obtained. Regenerated plants were rooted in half strength MS medium supplemented with 10 microM indole-butyric acid and successfully acclimatized. The plants regenerated from ozone treated callus are referred to as T(1), T(2) and T(3) plants, which hold remarkably increased soluble phenolic content compared to the control plants. All the plants were challenged by mechanical inoculation with Cucumber mosaic virus, shows disease incidence ranged from T(1)=32%, T(2)=56%, T(3)=78% and C=94%. Remarkable increase in activities of salicylic acid (SA), phenylalanine ammonia-lyase (PAL) and peroxidase (POX) were detected after Cucumber mosaic virus inoculation, in foliar extracts of T(1) plants than T(2) and T(3), compared to the control plants.

Chlorophyll↗
PubMed2006

Cholesterol granuloma of maxillary sinus.

The cholesterol granuloma is a particular form of granulation tissue developing as part of a variety of tissue reactions. It is usually associated with chronic middle ear disease and is common in the mastoid antrum of temporal bone. Cholesterol granuloma is rare in maxillary antrum. A case is reported of cholesterol granuloma in the maxillary sinus of a 42-year-old man, with the unique feature that the soft tissue lesion is enclosed by thick bone, entirely within the sinus.

Adult↗
PubMed2005

Self-fusion of protoplasts enhances chitinase production and biocontrol activity in Trichoderma harzianum.

Protoplasts were isolated from Trichoderma harzianum strain PTh18 using lysing enzymes and self-fusion of T. harzianum protoplasts was carried out using polyethylene glycol in STC buffer. The fused protoplasts of T. harzianum were regenerated and 15 self-fusants were selected to study the chitinase production and biocontrol activity. High chitinase activity was measured in the culture filtrates of most of the self-fusants (87%) than the parent. Among the fusants, the strain SFTh8 produced maximum chitinase with a two-fold increase as compared to the parent strain. All the self-fusants exhibited increased antagonistic activity against Rhizoctonia solani than the parent. The crude chitinase preparation of SFTh8 lysed the mycelia of T. harzianum, Trichoderma viride and Trichoderma reesei and released the protoplasts in higher number than the crude chitinase preparation of parent strain PTh18.

Chitinases↗
PubMed2005

Production of gliotoxin on natural substrates by Trichoderma virens.

Gliotoxin, an epithiodiketopiperazine toxin produced by the "Q" strain of Trichoderma virens, is essential for curtailing growth and multiplication of phytopathogens (Howell et al. 1993, Fravel 1988). Three isolates (Gv, Gv-A and Gv-V) of Trichoderma virens were grown on natural substrates such as bengal gram hull, gingelly cake, green gram hull, rice bran, soya meal, sugarcane bagasse, soyameal + tapioca, tapioca powder, tapioca peel and wheat bran). It was evident from this study that maximum gliotoxin (64 mg/l) was produced on tapioca powder by the alien isolate Gv. However sugarcane bagasse significantly enhanced gliotoxin production (36 mg/l) in the native isolate Gv-A, when compared to other substrates like green gram hull and rice bran. So far, studies on production of gliotoxin on synthetic media has been reported. We report the production of gliotoxin by T. virens on natural substrates "in vitro" for the first time.

Cellulose↗
PubMed2005

Antidermatophytic and bacterial activity of mimosine.

Mimosine, a non-protein aromatic amino acid was tested at 100, 50 and 25 microg/mL on some human pathogenic bacteria and fungi. Mimosine exhibited total lethality towards Trichophyton tonsurans and Trichophyton rubrum at 100 microg/mL. Among the tested bacteria Staphylococcus aureus was inhibited to a larger extent than the other bacteria. The studies revealed mimosine to be potent against fungi rather than bacteria. This study reports the effect of mimosine on dermatophytes for the first time.

Anti-Bacterial Agents↗
PubMed2003

Synthetic dye decolourization by white rot fungi.

Synthetic dyes are integral part of many industrial products. The effluents generated from textile dyeing units create major environmental problems and issues both in public and textile units. Industrial wastewater treatment is one of the major problems in the present scenario. Though, the physical and chemical methods offer some solutions to the problems, it is not affordable by the unit operators. Biological degradation is recognized as the most effective method for degrading the dye present in the waste. Research over a period of two decades had provided insight into the various aspects of biological degradation of dyes. It is observed that the white rot fungi have a non-specific enzyme system, which oxidizes the recalcitrant dyes. Detailed and extensive studies have been made and process developed for treatment of dye containing wastewaters by white rot fungi and their enzyme systems. An attempt is made to summarize the detailed research contributions on these lines.

Biodegradation, Environmental↗
PubMed2003

Xylanase production by Ganoderma lucidum on liquid and solid state fermentation.

Ganoderma lucidum, a white rot fungus, was exploited for its potentials to produce xylanase employing shake and solid-state culture conditions. Different culture conditions such as pH, temperature, carbon and nitrogen requirements for its growth and production of xylanase were optimized. The culture media pH 6.0-7.0 and temperatures 30 degrees-35 degrees C significantly promoted the growth as well as xylanase secretion into the media. Xylan and peptone were found to be the suitable carbon and nitrogen sources. Among the different agrowastes used, wheat bran was found to be the best substrate for the test fungus for the production of xylanase than sugarcane bagasse and rice bran in solid-state fermentation.

Electrophoresis, Polyacrylamide Gel↗
PubMed2003

Bioremediation of paper and pulp mill effluents.

Pulp and paper mill effluents pollute water, air and soil, causing a major threat to the environment. Several methods have been attempted by various researchers throughout the world for the removal of colour from pulp and paper mill effluents. The biological colour removal process uses several classes of microorganisms--bacteria, algae and fungi--to degrade the polymeric lignin derived chromophoric material. White rot fungi such as Phanerochaete chrysosporium, Corius versicolor, Trametes versicolor etc., are efficient in decolourizing paper and pulp mill effluents. Gliocladium virens, a saprophytic soil fungus decolourised paper and pulp mill effluents by 42% due to the production of hemicellulase, lignin peroxidase, manganese peroxidase and laccase.

Basidiomycota↗
PubMed2000

Influence of culture parameters on paper mill effluent decolourization by a white rot fungus Ganoderma lucidum.

Efficacy of a white rot fungus G. lucidum for reduction of colour of paper mill effluent under various growth conditions was evaluated. G. lucidum cultured in IBME medium supported maximum colour reduction on 18th day of fungal growth. The optimization of growth parameters further improved colour reduction. The 18 day old culture at 4 g/l inoculum concentration resulted in maximum decolourization (89%) of the effluent with pH adjusted to 6.5 at 35 degrees C along with maximum reduction in biological oxygen demand and chemical oxygen demand. Relative contribution of lignin peroxidase and laccase to the decolourization of paper mill effluent by G. lucidum was also observed.

Biodegradation, Environmental↗
PubMed1998

Purification, characterization, and antifungal activity of chitinase from Fusarium chlamydosporum, a mycoparasite to groundnut rust, Puccinia arachidis.

Chitinase (EC 3.2.1.14) was isolated from the culture filtrate of Fusarium chlamydosporum and purified by ion-exchange chromatography and gel filtration. The molecular mass of purified chitinase was 40 kDa as estimated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Chitinase was optimally active at a pH of 5 and stable from pH 4 to 6 and up to 40 degrees C. Among the metals and inhibitors tested, mercuric chloride completely inhibited the enzyme activity. The activity of chitinase was high on colloidal and pure chitin. The purified chitinase inhibited the germination of uredospores of Puccinia arachidis and also lysed the walls of uredospores and germ tubes. The results from these experiments indicated that chitinase of F. chlamydosporum plays an important role in the biocontrol of groundnut rust.

Antifungal Agents↗
PubMed1996

Effect of antiprogestin RU 486 on the proliferation and metabolic activity of stromal cells separated from human endometrium.

The effects of RU 486 on the proliferation and metabolic activity of human endometrial stromal cells in culture were studied. RU 486 at 10(-7) M/well significantly stimulated (P < 0.001) the growth as well as metabolic activity in the culture system. Interestingly, RU 486 at 10(-6) M/well did not stimulate metabolic activity in the culture. Progesterone, in combination with RU 486 at 10(-7) M/well, caused a significant increase in proliferation (assessed by thymidine incorporation) (P < 0.001) over control and P4 alone, but not significantly different from RU 486 at 10(-7) M/well alone. The same pattern was observed for metabolic functions (assessed by uridine incorporation) when RU 486 at 10(-7) M/well, along with P4, was added to the culture. Interestingly, RU 486 at 10(-6) M/well with P4 had no effect on RNA synthesis in the culture. The relevance of these findings is discussed.

Cell Division↗
PubMed1996

Effect of hormones and antihormones on phospholipase A2 activity in human endometrial stromal cells.

Phospholipase A2 activity was studied in isolated human endometrial predecidual cells, and in human endometrium collected from day 19-23 of the menstrual cycle, by performing a radiochemical assay. Phospholipase A2 activity on day 20 was significantly higher than other days (P < 0.001), and the activity was found to gradually decrease after day 20 of the menstrual cycle. The effects of the hormones estradiol and progesterone, and antihormones tamoxifen and RU 486, were studied on the phospholipase A2 activity in isolated predecidual stromal cells. Estradiol produced a significant stimulatory effect (P < 0.001) on phospholipase A2 activity in predecidual cells, and this effect was antagonized by tamoxifen. The combination of estradiol and tamoxifen was significantly different from estradiol alone (P < 0.001), but not from tamoxifen alone. RU 486 alone significantly increased (P < 0.001) phospholipase A2 activity in predecidual stromal cells. However, progesterone had no effect on phospholipase A2 activity in predecidual stromal cells.

Analysis of Variance↗
PubMed1995

Serum norethindrone levels and menstrual pattern after the use of norethindrone implants in rhesus monkeys.

Subdermal Silastic implants releasing norethindrone (NET) were inserted in five rhesus monkeys for a period of seven months. The total length of the implants used was 160 mm (eight implants of 20 mm each) containing 160 mg of NET (1 mg NET/mm). The in vivo release rate of NET from the Silastic implants containing 160 mg NET was 3.12 micrograms/day/mm. Menstrual bleeding records were maintained and serum NET levels were estimated from blood samples collected during the period implants remained in situ. There was an initial rise in NET levels, followed by fluctuating levels of NET in three out of five monkeys. The menstrual cycle or bleeding episodes showed a pattern commensurate with the circulating NET levels. None of the monkeys showed intermenstrual bleeding during the treatment period. High levels of NET seem advantageous for an undisturbed menstrual cycle.

Animals↗
PubMed1995

Tamoxifen increases the proliferation of human endometrial stromal cells in in vitro. A model for evaluation of endometrial hyperplasia.

Tamoxifen given for breast cancer therapy, has a complex and an unclear action on the endometrium. A large number of literatures has attributed the proliferous changes in the endometrium caused by tamoxifen (Tam). No report has appeared on the endometrial cellular changes induced by Tam. The present study shows a significant (P < 0.001) increase in the proliferative activity due to Tam in endometrial stromal cells over control and estradiol (E2). This in vitro model is useful for the study of the hyperplasic effect of Tam at the cellular level.

Cell Division↗
PubMed1993

Effect of tamoxifen, estradiol 17 beta on coenzymes NAD, NADPH and the metabolism of estradiol and estrone in rabbit uterus in vivo.

Biotransformation of estradiol (E2) and estrone (E1) and the concentrations of NAD, NADPH and 17 beta-estradiol dehydrogenase (E2DH) were measured in the uterus of rabbits treated with tamoxifen (Tam) in two doses; 100 micrograms/day, (Tam 100) and 500 micrograms/day, (Tam 500), E2 (10 micrograms/day) and combination of E2 + Tam 500 for 4 days. The concentration of NAD in Tam 500 treated group was significantly higher than E2, low dose Tam and E2 + Tam 500 treated groups (P < 0.01). The concentration of NAD in E2+ Tam 500 uteri was also significantly higher than E2 treated uteri. The concentration of NADPH was not significantly different from each other amongst the various treatment groups. The studies have shown that E2DH in E2 treated uteri was less than control and Tam 500 treated groups. A significant rise in the enzyme estradiol oxidoreductase (E2OR) activity (P < 0.02) was observed in E2 + Tam 500 treated uteri over control and other treated groups whereas high dose Tam decreased the E2OR activity significantly over the E2 treated group. The rate of conversion of E1 to E2 in Tam 500 treated group was significantly less than the other treatment groups except E2 + Tam 500 treated group (P < 0.04). This study showed that E2 decreases the uterine biosynthesis of NAD and E2DH and the biotransformation of E2 to E1, while high dose Tam increases uterine NAD, E2DH activity and E2 to E1 conversion.

Animals↗
PubMed1993

Short term treatment of tamoxifen and estradiol on estradiol and progesterone receptors in rabbit uterus.

Effects of tamoxifen (Tam) on cytosolic estradiol (E2) receptors (ERc), progesterone (P4) receptors (PRc), nuclear estradiol (ERn) and progesterone receptors (PRn) were studied in adult normal rabbit uterine tissue. The ratio of cytosol: nuclear estradiol receptors (ER) was greater in rabbits treated with Tam than E2 or control uterine tissues. Rabbit uterine progesterone receptors (PR) in E2 treated animal were greater than Tam-treated animals. Tam caused nuclear accumulation of estradiol receptor, and simultaneous administration of E2 + Tam 500, estradiol could not revert Tam mediated accumulation of ER. The results suggest that Tam has an essentially antagonist action in the rabbit uterine tissue.

Animals↗