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J S Prasad

Publications and source records attributed to J S Prasad.

At least 19 recordsLinked to original sources
PubMed1997

Endoglucanase production by paper-degrading mycoflora.

Fourteen fungal species, namely Aspergillus flavus, A. fumigatus, A. niger, A. ustus, Penicillium islandicum, P. wortmannii, Memnoniella echinata, Cladosporium herbarum, Stachybotrys atra, Chaetomium globosum, Fusarium oxysporum, Torula herbarum, Alternaria alternata and Curvularia uncinata were isolated from different grades of paper. They differ in their distribution on various kinds of paper and also in relative occurrence. While seasonal influence on mycoflora was observed, most of the moulds were capable of growing in all three seasons examined (summer, winter, rainy season). The moulds were cellulolytic in nature and endoglucanase activity was greatest in Aspergillus flavus, A. niger, A. fumigatus, P. wortmannii and P. islandicum.

Cellulase↗
PubMed1990

Effects of ethanol and inhibitors on the binding and metabolism of acetaminophen and N-acetyl-p-benzoquinone imine by hepatic microsomes from control and ethanol-treated rats.

Acetaminophen is metabolized by cytochrome P450 to N-acetyl-p-benzoquinone imine (NABQI). This metabolite reacts with critical cellular macromolecules to give toxicity. The administration of 10% ethanol in the drinking water to 100 g male rats for 6 weeks markedly increases the toxicity of acetaminophen. This increase was associated with a 71% increase in microsomal protein binding of acetaminophen [4.8 pmol/min/mg protein in control microsomes versus 8.2 pmol/min/mg protein in ethanol microsomes (P less than 0.01)] and a 131% increase in aniline hydroxylase [0.52 nmol/min/mg protein in control microsomes versus 1.20 nmol/min/mg protein in ethanol microsomes (P less than 0.001)]. On the other hand, cysteine conjugation of acetaminophen showed an increase of only 12% [2.8 nmol/min/mg protein in control microsomes versus 3.1 nmol/min/mg protein in ethanol microsomes (P less than 0.05)]. Ethylmorphine- and benzphetamine N-demethylases did not increase. In microsomes from both control and ethanol animals, imidazole (1 mM) inhibited the two N-demethylases, aniline hydroxylation and acetaminophen binding by 85-95% but inhibited the cysteine conjugation by only 50%. For control and ethanol animals, both 80% CO/20% O2 and SKF-525A (1 mM) totally inhibited cysteine conjugation but only inhibited the other activities by about 36-60%. KCN (1 mM) had no effect on any of the activities except protein binding (60-67% inhibition). Scavengers of reactive oxygen [mannitol (1 mM), dimethyl sulfoxide (1 mM), superoxide dismutase (15 micrograms/mL) and catalase (65 micrograms/mL)] had no effect on any of the reactions. Of all these treatments only CO/O2 decreased the protein binding and cysteine conjugation of NABQI in the presence of either NADP+ or NADPH. The data from the inhibitor studies and the effect of ethanol on acetaminophen and NABQI metabolism would suggest that protein binding and cysteine conjugation are catalyzed by different isozymes of cytochrome P450. Finally, the current results indicate that the increased toxicity of acetaminophen observed with ethanol more closely parallels the increase in protein binding activity rather than cysteine conjugation.

Acetaminophen↗
PubMed1987

The role of NADPH- and reduced glutathione-dependent enzymes in the norepinephrine modulation of the ATP-dependent, hepatic microsomal calcium pump: a new pathway for the noradrenergic regulation of cytosolic calcium in the hepatocyte.

The authors have recently found that the hepatic, microsomal ATP-dependent Ca++ pump activity is decreased through oxidation by cytochrome P-450-generated reactive oxygen species. This inhibition is reversed by reduced glutathione and only partially reversed by reactive oxygen scavengers. In view of these observations, the authors have sought to determine whether norepinephrine could regulate the Ca++ pump by differential modulation of the oxidative and reductive pathways. They find that, in the presence of superoxide dismutase (15 micrograms/ml), catalase (65 micrograms/ml), reduced glutathione (5 mM) and NADP+ (0.39 mM), the pump activity was maximal 142% of no norepinephrine at 10(-11) to 10(-10) M norepinephrine and decreased with increasing concentrations of norepinephrine. NADPH had no effect on uptake at 10(-11) M norepinephrine, but, between 10(-10) and 10(-8) M norepinephrine, it significantly decreased uptake compared with NADP+. At 10(-7) to 10(-6) M norepinephrine, with either NADP+ or NADPH, the uptake was significantly lower than at other norepinephrine concentrations. This decrease in the uptake seen at 10(-7) to 10(-6) M norepinephrine disappeared on the addition of 0.25 microM l-(S)-propranolol. The NADPH inhibition of the pump was blocked by imidazole-histidine buffer but not by inhibitors of mitochondrial metabolism. ATP and norepinephrine had little effect on mitochondrial uptake. These studies suggest that norepinephrine may modulate the hepatic, microsomal ATP-dependent Ca++ pump through alterations in the balance between oxidative and reductive pathways.

Adenosine Triphosphate↗
PubMed1986

The effect of cytochrome P-450 and reduced glutathione on the ATP-dependent calcium pump of hepatic microsomes from male rats.

In the presence of ATP hepatic microsomes sequester calcium. This sequestration is thought to be important in the modulation of free cytosolic calcium concentration. We find that on the addition of NADPH the uptake of calcium by the hepatic microsomes is inhibited 27-85%. This inhibition is reversed by the addition of 1 mM reduced glutathione (85-91% of control), incubation under a nitrogen atmosphere (112% of control), or incubation in a 80% carbon monoxide/20% oxygen atmosphere (75% of control). Superoxide dismutase had no effect on the inhibition, while catalase reversed the inhibition by 35%. The addition of 1 mM reduced glutathione at 2 and 5 min after the addition of NADPH led to uptakes of calcium which paralleled the uptake seen when the reduced glutathione was added at the beginning of the incubation. The effect of reduced glutathione showed saturation kinetics with a Km of 10 microM. Together these data suggest that cytochrome P-450 reduces the activity of the microsomal ATP-dependent calcium pump both by the production of hydrogen peroxide and by the direct oxidation of the protein thiols. The reversal of this effect by reduced glutathione appears to be enzymatically catalyzed.

Animals↗
PubMed1986

C(3)-C(4) Intermediate Species in Alternanthera (Amaranthaceae) : Leaf Anatomy, CO(2) Compensation Point, Net CO(2) Exchange and Activities of Photosynthetic Enzymes.

Two naturally occurring species of the genus Alternanthera, namely A. ficoides and A. tenella, were identified as C(3)-C(4) intermediates based on leaf anatomy, photosynthetic CO(2) compensation point (Gamma), O(2) response of small ghe, Cyrillic, light intensity response of small ghe, Cyrillic, and the activities of key enzymes of photosynthesis. A. ficoides and A. tenella exhibited a less distinct Kranz-like leaf anatomy with substantial accumulation of starch both in mesophyll and bundle sheath cells. Photosynthetic CO(2) compensation points of these two intermediate species at 29 degrees C were much lower than in C(3) plants and ranged from 18 to 22 microliters per liter. Although A. ficoides and A. tenella exhibited similar intermediacy in small ghe, Cyrillic, the apparent photorespiratory component of O(2) inhibition in A. ficoides is lower than in A. tenella. The small ghe, Cyrillic progressively decreases from 35 microliters per liter at lowest light intensity to 18 microliters per liter at highest light intensity in A. tenella. It was, however, constant in A. ficoides at 20 to 25 microliters per liter between light intensities measured. The rates of net photosynthesis at 21% O(2) and 29 degrees C by A. ficoides and A. tenella were 25 to 28 milligrams CO(2) per square decimeter per hour which are intermediate between values obtained for Tridax procumbens and A. pungens, C(3) and C(4) species, respectively. The activities of key enzymes of C(4) photosynthesis, phosphoenolpyruvate carboxylase, pyruvate Pi dikinase, NAD malic enzyme, NADP malic enzyme and phosphoenolpyruvate carboxykinase in the two intermediates, A. ficoides and A. tenella are very low or insignificant. Results indicated that the relatively low apparent photorespiratory component in these two species is presumably the basis for the C(3)-C(4) intermediate photosynthesis.

Journal Article↗
PubMed1985

Studies on the effect of chronic consumption of moderate amounts of ethanol on male rat hepatic microsomal drug-metabolizing activity.

Weanling, male Sprague-Dawley rats given 10% ethanol in the drinking water and food ad lib. for up to 8 weeks consumed 17% of their calories as ethanol. The alanine aminotransferase (ALT), aspartate aminotransferase (AST), and liver histology by light microscopy were unaffected by this treatment. Similarly, hepatic microsomal NADPH-cytochrome c reductase, ethylmorphine N-demethylase and benzphetamine N-demethylase activities were also not affected by ethanol consumption. On the other hand, cytochrome P-450 content, aniline hydroxylase activity and acetaminophen metabolism as measured by both the cysteine conjugate and the [3H]acetaminophen covalently-bound to microsomal protein were increased significantly by ethanol consumption. The maximal effect was seen by 6 weeks. The 2- to 3-fold increase in aniline and acetaminophen metabolism, the absence of liver damage, and the similarity in weight gains and caloric intakes for controls and treated animals suggest that the rat on 10% ethanol in the drinking water is a reasonable model for studies of the effect of moderate alcohol consumption on specific biochemical pathways.

Acetaminophen↗
PubMed1983

Cultural control of the root nematodes Pratylenchus indicus in rice through crop rotations.

Pratylenchus indicus nematodes cause damage to the roots of rice plants, which may lead to considerable yield reductions. In field trials with six different rice-based rotations it was tested whether the inclusion of other crops into the rotation can influence the population of Pratylenchus indicus. Investigation of soil samples and roots showed that rice, safflower, and tobacco increased the nematodes, whereas fallowing or growing Phaseolus radiatus L. decreased them.

Agriculture↗
PubMed1980

Effect of vitamin E supplementation on leukocyte function.

The effect of megadoses of vitamin E was studied in 13 adult males and five young boys. Three hundred milligrams of vitamin E as dl-alpha-tocopheryl acetate, given daily for a period of 3 weeks produced a significant depression in the bactericidal activity of the leukocyte and the mitogen induced lymphocyte transformation. The delayed hypersensitivity of the skin to phytohemagglutinin was, however, not affected by the supplementation. The implication of the study and the discrepancy between the in vitro and the in vivo results of the cell-mediated immunity are discussed.

Adolescent↗
PubMed1979

Leucocyte function in iron-deficiency anemia.

Production of hydrogenperoxide and myeloperoxidase-mediated iodination, by leucocytes was studied in normal subjects and subjects suffering from iron-deficiency anemia. The leucocytes obtained from severe cases of iron-deficiency anemia showed decreased myeloperoxidase-mediated iodination. Defective myeloperoxidase-mediated iodination can explain the basis for the leucocyte microbicidal defect in iron deficiency anemia.

Anemia, Hypochromic↗
PubMed1978

Streptomycin pharmacokinetics in malnutrition.

Pharmacokinetic parameters of streptomycin such as plasma concentration, plasma half-life, urinary excretion, and in vitro and in vivo binding to plasma proteins were studied in undernourished and well-nourished individuals. None of the parameters studied were different in undernourished subjects as compared to those in well-nourished, in spite of significant differences in mean albumin values between the two groups. This may be attributed to unaltered protein binding of the drug in undernourished subjects in spite of low serum albumin levels, since streptomycin binds to globulins, in addition to albumin.

Adult↗
PubMed1977

An animal model to study iron availability from human diets.

1. The retention of ferric- and ferrous-iron was determined in guinea-pigs and monkeys using 55Fe and 59Fe. 2. The bioavailability of Fe from two typical Indian diets based on rice and wheat was determined in humans and monkeys using a 59Fe tracer and whole-body counting. 3. The retention ratio, ferric-Fe; ferrous-Fe was 0-90 in guinea-pigs and 0-33 in monkeys, indicating that monkeys absorb ferrous-Fe preferentially. 4. In monkeys retention of Fe from the test diets, as from ferrous ascorbate was lower than that in humans. 5. When food-Fe retention was expressed in relation to inorganic-Fe retention the value for retention ratio, food Fe: inorganic Fe in monkeys was similar to that in human subjects. 6. The results indicate that the monkey can be used as a model to study Fe absorption from human diets.

Anemia, Hypochromic↗
PubMed1976

Anaemia and immune response.

Nutritional anaemia is a major public-health problem in many parts of the world, and iron deficiency appears to be the most important cause. The immune response is believed to be impaired in anaemia. The results of the present study, carried out in young children, indicate that both the cell-mediated immune response and the bactericidal activity of leucocytes are impaired when levels of haemoglobin fall to 10 g/dl or less.

Adolescent↗