Showing papers by "Banaras Hindu University published in 1994"

Evaluation of some essential oils for their toxicity against fungi causing deterioration of stored food commodities.

Abstract: During screening of essential oils for their antifungal activities against Aspergillus flavus, the essential oil of Cymbopogon citratus was found to exhibit fungitoxicity. The MIC of the oil was found to be 1,000 ppm, at which it showed its fungistatic nature, wide fungitoxic spectrum, nonphytotoxic nature, and superiority over synthetic fungicides, i.e., Agrosan G. N., Thiride, Ceresan, Dithane M-45, Agrozim, Bavistin, Emison, Thiovit, wettable sulfur, and copper oxychloride. The fungitoxic potency of the oil remained unaltered for 7 months of storage and upon introduction of high doses of inoculum of the test fungus. It was thermostable in nature with treatment at 5 to 100 degrees C. These findings thus indicate the possibility of exploitation of the essential oil of C. citratus as an effective inhibitor of storage fungi.

Evaluation of air pollution phytotoxicity in a seasonally dry tropical urban environment using three woody perennials

Abstract: SUMMARY A two-year study was conducted in the urban environment of Varanasi, India, to evaluate plant responses to urban air pollution. Three species including a shrub (Carissa carandas L.) and two tree species (Delonix regia Rafin and Cassia fistula L.) were grown in pots at selected study sites. Changes in plant performance were considered in relation to the status of ambient air quality. Reductions in plant height, basal diameter, canopy area, plant biomass and chlorophyll, ascorbic acid and nitrogen contents in leaves were correlated with air pollution level at different sites. The magnitude of response indicated the relative sensitivity of the three species in the order D. regia > C. fistula > C. carandas. Shifts in relative contribution of photosynthate to leaf production and shoot growth appear to be a pollution-induced adaptive response in C. carandas. The study shows that the urban air pollution level at Varanasi is detrimental to the growth of plants.

Sensing mechanism in tin oxide-based thick-film gas sensors

Abstract: A model has been developed for the sensing mechanism of metal oxide-based thick-film gas sensors. The model explains the behaviour of the sensor conductance as a function of the concentration of test gas and the operating temperature of the sensor. Using the Schottky-barrier conduction mechanism through grain boundaries, a relationship between the degree of surface coverage θ and the conductance G has been obtained. To relate the conductance with the concentration of the gas, the Freundlich adsorption isotherm for gases and vapours on a solid surface has been used. The isotherm relates the degree of surface coverage θ with the partial pressure of the gas (concentration). By eliminating θ, an expression relating the variation of G with concentration has been obtained. To study the validity of the model, a thick-film Pd-doped tin oxide gas sensor has been fabricated and tested with propanol (C3H7OH). The variation in the conductance with changes in concentration and temperature has been observed. The observed data show an excellent fit with the developed model. Using the experimental data, the constants of the theoretical equation have also been evaluated.

Oocytic tumor necrosis factor alpha: localization in the neonatal ovary and throughout follicular development in the adult rat.

Abstract: Tumor necrosis factor alpha (TNFa) has previously been immunolocalized within mouse oocytes. Our first objective was to examine TNFa immunolocalization in ovaries of adult, fetal, and neonatal rats. Our second objective was to examine TNFa mRNA in ovaries by Northern blot analysis and in oocytes by reverse-transcriptase polymerase chain reaction (RT-PCR). Our final objective was to determine whether oocytes contained bioactive TNFa. Ovaries and oviducts were collected throughout the estrous cycle in adult rats, fetal ovaries were obtained 1 day before expected delivery, and neonatal ovaries were collected 2 days after birth. TNFa was localized in tissues by a biotin-avidin immunocytochemical procedure. Immunocytochemistry in adult ovaries showed that the ooplasm of the oocyte was the primary site of TNFa localization within the follicle. Immunostaining was present in all oocytes in the adult, including ovulated oocytes within the oviduct. Oocytic TNFa immunostaining was also present within oocytes in the neonate; however, fetal oocytes did not contain immunoreactive TNFao. Northern blots showed that ovaries in the adult, neonate, and fetus all contained TNFa mRNA. RT-PCR analysis of oocytes collected from preovulatory follicles generated a cDNA band of 500 bp, corresponding to the predicted size for amplified TNFa cDNA. Subsequent Southern blot analysis showed that the 500-bp band hybridized to the TNFat probe, indicating that preovulatory oocytes contain TNFoa mRNA. Preovulatory oocytes were used in TNFai cytotoxicity assays with L929 cells. Oocytes contained TNFat bioactivity that was similar to that of recombinant murine TNFa in the bioassay. Our results provide evidence for the identification of immunoreactive and bioactive TNFa within oocytes in the rat, which is further supported by the presence of TNFca mRNA within the oocyte. These studies also indicate that TNFa may appear in the oocyte around the time of birth.

Congenital malformations at birth.

Abstract: Three thousand nine hundred and thirty-two consecutive newborns were examined at birth for the presence of congenital malformations. The overall incidence of malformations was 1.2%. Congenital malformations accounted for 9.2% of perinatal and 12.8% of neonatal deaths. The central nervous system (39.5%) was most commonly involved followed by musculoskeletal system (14.5%). Involvement of more than one system was observed in 18.8% cases. Though there was higher incidence of malformations in babies born to mothers of more than 35 years the difference was not statistically significant. However, the babies born to mothers of gravidity 4 or more had significantly higher incidence of malformation when compared to mothers of lower gravidity (chi1(2) = 4.67, p < 0.05). The incidence of congenital malformations at birth was higher in stillborn and low birthweight babies.

Thermal arrest memory effect

Abstract: The course of the martensitic transformation is affected by strain fields in the untransformed parent phase, One of the consequences of this NiTi shape memory alloys is the “Thermal Arrest Memory Effect” (TAME), where the martensite to parent phase transformation “remembers” the temperature of arrest in the previous thermal cycle. From the results of the calorimetric investigations in this study, it is deduced that the TAME is the result of locked-in transformation strain energy in the self-accomodating martensitic microstructure. Thus it is found that on account of the large difference in the degree of self-accomodation achieved in the martensitic microstructures, TAME is observed to be significant in NiTi and not in CuAnAl shape memory alloys.

Genes and Aging

Abstract: The maximum life span of multicellular organisms varies greatly: for a fruitfly it is about 30 days, for a dog about 20 years, and for a human about 100 years. Despite these differences, all animals show a similar pattern of their life spans - growth, adulthood, and aging, followed by death. The basic cause of aging in multicellular organisms (eukaryotes) lies at the level of the genes, although nutrition and various types of stresses do influence the rate and pattern of aging. This book reviews the molecular biology of the gene in relation to aging. Until about a decade ago it was not possible to probe into the types of changes that occur in eukaryotic genes, due to their enormous complexity. The use of genetic engineering techniques, however, is beginning to unravel the changes that occur in the genes as an organism ages: such as the changing expression of specific genes under normal conditions and under various types of stress, the changes in the regulatory roles of the sequences in the promotor regions of genes, conformational changes that may occur in genes during aging, and the protein factors that are involved in the aging process. The author presents basic information on eukaryotic genes and follows this with details of the changes that occur in their structure and function during aging. He reviews the latest studies being carried out in various laboratories, outlines the gaps and deficiencies in our present knowledge and suggests the most profitable future areas of research. Genes and Aging is for all students and researchers interested in the molecular biology of aging.

Role of Serotonin and Prostaglandins in Brain Edema Induced by Heat Stress. An Experimental Study in the Young Rat

Abstract: The possibility that serotonin and prostaglandins participate in edema formation following heat stress (HS) was examined in young rats. Exposure of conscious young animals (8-9 weeks old) to heat at 38°C in a biological oxygen demand (BOD) incubator (relative humidity 50-55%; wind velocity 20-25 cm/s) for 4 h resulted in marked increase in the whole brain water content (about 3%) as compared to animals kept at room temperature (21°C). A marked extravasation of Evans blue and 131I-sodium occurred in the brain of heat exposed animals as compared to normal animals. Morphological examination using electron microscopy of selected brain regions of heat stressed animals showed profound cell changes. Thus perivascular edema, swollen neuronal and glial cells, membrane damage, vesiculation of myelin, axonal swelling and synaptic damage was frequent in this group of untreated animals. Pretreatment with ketanserin (a selective serotonin2 receptor antagonist) or indomethacin (an inhibitor of prostaglandin synthesis) markedly reduced edema formation after 4 h HS in young animals. These heat stressed animals had considerably less extravasation of protein tracers as compared to the untreated group. Cell changes and edema at the ultrastructural level were mainly absent. Our results suggest that serotonin and prostaglandins are involved in heat stress induced breakdown of the BBB permeability, edema formation, and cell damage.

Induction of ornithine-urea cycle in a freshwater teleost, Heteropneustes fossilis, exposed to high concentrations of ammonium chloride

Abstract: An ammoniotelic freshwater teleost, Heteropneustes fossilis , tolerated ambient ammonium chloride concentration up to 75 mM. Ammonia accumulated significantly in all the tissues within 7 days of treatment and the concentration remained high throughout the 4-week period of treatment. The activity of enzymes of the ornithine-urea (o-u) cycle were induced within 7 days, and thereafter remained high in both the liver and kidney of the fish. Urea accumulated significantly in various tissues simultaneous with the induction of o-u cycle enzymes. Accumulated ammonia induced the activity of the enzymes of the o-u cycle for its metabolic conversion to urea. This helped the freshwater fish to avoid toxaemia and to tolerate high concentrations of ammonia in the ambient medium.

Anxiolytic activity of Azadirachta indica leaf extract in rats.

Abstract: Putative anxiolytic activity of leaf extract of A. indica, was investigated and compared with that of diazepam in rats using elevated plus maze and open field behaviour test paradigms of anxiety. Doses (10, 20, 50, 100, 200, 400 and 800 mg/kg) of freshly prepared leaf extract of A. indica and diazepam (1 mg/kg) were administered (po) once, 45 min prior to behavioural testing. Low doses (10, 20, 50, 100 and 200 mg/kg) of A. indica leaf extract produced significant antianxiety effects both in plus maze and open field test. However, the higher doses of leaf extract (400 and 800 mg/kg) did not show anxiolytic activity. The effects induced by low doses (10, 20, 50, 100, 200 mg/kg) of extract were comparable to those of induced by diazepam (1 mg/kg).

Transdermal delivery of propranolol

Abstract: Three transdermal formulations containing propranolol hydrochloride in a hydrophilic polymer matrix were prepared-one without a rate controlling membrane(H-1), one with a 20μ thick Ethylene Vinyl Acetate(EVA) rate controlling membrane (H-2) and one with a 65μ thick EVA membrane. These patches were evaluated for their in-vitro performance. Cumulative % permeated across excised hairfree rat skin were 79.2% from H-1, 65.53% from H-2 and 53.44% from H-3. Increase in thickness of EVA lead to greater retention of drug in device and a zero order profile was seen with patches H-2 & H-3. Matrix diffusion profile was observed with H-1 patch.

Protective effect of Rubia cordifolia on lipid peroxide formation in isolated rat liver homogenate.

Abstract: Rubia cordifolia Linn. (Rubiaceae) is an important component of the ayurvedic system of medicine. It has a variety of uses such as blood purifier, immunomodulant, antiinflammatory and anti-PAF. In this report the anti-peroxidative property of the solvent free alcoholic extract of R. cordifolia has been studied in rat liver homogenate. It prevents the cumene hydroperoxide induced malondialdehyde formation in the dose and time dependent manner. This effect is accompanied by the maintained reduced glutathione level even in the presence of above toxin.

Antifungal potential of leaves and essential oils from higher plants against soil phytopathogens

Abstract: During screening of leaves of 30 angiospermic taxa for their fungitoxicity against Pythium aphanidermatum and P. debaryanum; Hyptis suaveolens (Labiatae), Murraya koenigii (Rutaceae) and Ocimum canum (Labiatae) showed strong toxicity. The essential oils of H. suaveolens, M. koenigii and O. canum could control damping-off disease of tomato (Lycopersicon esculentum) up to 83, 67 and 50% respectively in soil infected with P. aphanidermatum and 86, 71 and 43% respectively in soil infected with P. debaryanum. The oils showed selective fungitoxicity and were not phytotoxic. Soil amendments with leaves of these fungitoxic plants increased the saprophytic fungal community.

Effects of ovariectomy and oestradiol replacement on hypothalamic serotonergic and monoamine oxidase activity in the catfish, Heteropneustes fossilis: a study correlating plasma oestradiol and gonadotrophin levels.

Abstract: Hypothalamic serotonin (5-HT; content and turnover) and monoamine oxidase (MAO) activity were measured in female catfish, Heteropneustes fossilis, after ovariectomy and supplementation with oestradiol-17 beta (OE2) in the recrudescent and quiescent phases. These factors were correlated with changes in plasma levels of OE2 and gonadotrophin. In the quiescent phase (December), neither ovariectomy nor OE2 supplementation had any significant effect on 5-HT content and MAO activity. Plasma levels of OE2 and gonadotrophin were undetectable in both control and treated fish, indicating that there was no feedback effect. In the recrudescent phase (prespawning, May), ovariectomy caused biphasic responses of MAO activity and 5-HT content. The enzyme activity decreased significantly after 2, 3, 4 and 5 weeks but increased significantly 6 weeks after ovariectomy. The 5-HT content varied in a biphasic manner with a significant increase at 2, 3 or 4 weeks and a significant decrease in week 6; there being no effect in week 5. 5-HT turnover was inhibited significantly only in week 4 after ovariectomy and did not show a biphasic pattern. In the ovariectomized groups, the OE2 level decreased significantly in a progressive manner with a maximum reduction in week 6. The plasma level of gonadotrophin showed a significant bimodal pattern of increase with the peak in week 4 after ovariectomy, indicating a strong negative feedback effect of OE2. The bimodal pattern of pituitary gonadotrophin release could be correlated with a similar pattern of increase in 5-HT content. OE2 treatment of fish which had been ovariectomized 3 weeks previously had dose-dependent effects on the enzyme; the low dose (0.1 microgram/g body weight) was stimulatory and the higher doses (0.5, 1.0 and 5.0 micrograms/g body weight) were inhibitory. The reverse was true for 5-HT content. Serotonergic turnover increased significantly only in the groups given high doses (1.0 and 5.0 micrograms/g body weight). The low dose of OE2 (0.1 micrograms/g body weight) restored the gonadotrophin and OE2 levels to those of the sham-ovariectomized vehicle-treated control group, whereas the high doses (0.5, 1.0 and 5.0 micrograms/g body weight) decreased the release of gonadotrophin in a dose-dependent manner. Our results suggest that OE2 modulates MAO activity to alter hypothalamic 5-HT in a seasonally dependent manner. The ovariectomy-induced changes in plasma levels of gonadotrophin appear to be mediated, at least partly, by the feedback action of OE2 on 5-HT metabolism.

Nitrogen and phosphorus availability and mineralization in dryland reduced tillage cultivation: effects of residue placement and chemical fertilizer.

Abstract: Proper residue management may help augment soil fertility in dryland farming systems in the developing countries. We report on the effect of residue placement and chemical fertilizer on available nutrient pools (N and P) and N-mineralization in dryland reduced tillage cultivation. Four treatments (control, fertilizer, straw, and straw + fertilizer) were initiated in June 1990 under dryland farming conditions (rice and lentil rotation) in an attempt to improve nutrient availability and plant growth. Plant available pools (N and P) and N-mineralization rates were measured periodically. Available N ranged from 7.0 to 25.5 μg Ng −1 dry soil, maximum values were found for the fertilizer treated plots (45–66% greater than control) followed in decreasing order by straw + fertilizer, straw and control plots. N-mineralization rate ranged from 2.7 to 24.2 μg g −1 month −1 . The increase in nitrogen mineralization in straw + fertilizer treatment was 97% over the control. The rate of N-mineralization was greatest during the wet period of the year. It increased exponentially with increase in soil moisture content from 5–23%, indicating that the N-mineralization process is moisture limited in these drylands. At similar moisture content, straw + fertilizer treatment resulted in greater rate of N-mineralization compared to the control. Available P ranged from 7.9 to 17.7 μg Pg −1 dry soil. From 26 to 69% increase in available P was found in straw + fertilizer treated plots. Both available P and mineralization rates were maximum in straw + fertilizer treated plots and minimum in control plots. In conclusion, straw + fertilizer application substantially increased available nutrient pools, and also the rate of N-mineralization, particularly in the wet period.

Athermal physiological effects of microwaves on a cynobacterium Nostoc muscorum: evidence for EM-memory bits in water

Abstract: Athermal physiological effects of continuous wave and modulated microwaves were studied on a cynobacterium Nostoc muscorum. The study shows that different microwave frequencies in continuous wave and modulated modes produced significantly different physiological effects on the algae. Water-mediated bioeffects further present additional proof that water has the capability to remember the imposed electromagnetic field characteristics for an extended period of time.

Inhibition of Copper Corrosion in Aqueous Sodium Chloride Solution by Various Forms of the Piperidine Moiety

Abstract: The inhibition of copper (Cu) corrosion in 1.5% sodium chloride (NaCl) solution was studied in the presence of different concentrations of piperidine, piperidine dithiocarbamate, and its C...

Lipid peroxidation product in bile from patients with carcinoma of the gallbladder: a preliminary study.

Abstract: Samples of gall bladder bile from patients with and without carcinoma of the gallbladder were examined for lipid peroxidation (free radical oxidation) products. 4-hydroxynonenal (HNE) was found in higher concentration in the bile of patients with carcinoma of the gall bladder. There was also a highly significant difference in the concentration of HNE among carcinoma of the gall bladder, cholelithiasis and control group of patients with miscellaneous abdominal disorders. This is the first study of lipid peroxidation in carcinoma of the gall bladder. © 1994 Wiley-Liss, Inc.

Preparation and characterization of thin films of LaNiO3 for anode application in alkaline water electrolysis

Abstract: LaNiO3 electrodes were prepared, in the form of thin films on platinum by the methods of spray pyrolysis and sequential coating of mixed metal nitrate solutions followed by thermal decomposition. The films were adherent and of p-type semiconducting. Cyclic voltammetric studies indicated the formation of a quasireversible surface redox couple, Ni(iii)/Ni(ii), on these films before the onset of oxygen evolution in 1 m KOH. The anodic Tafel slopes were ∼40 and ∼65 mV decade−1, on the sprayed LaNiO3 film and on the film obtained by a layer method, respectively. The reaction order with respect to OH− was found to be 2.2 on the sprayed oxide film and 1.2 on the layer film. The sprayed oxide film was found to be electrocatalytically more active. It is suggested that the oxygen evolution reaction proceeds on both the film electrodes via the formation of the physisorbed H2O2 as an intermediate in the rate determining step.

Structure and Properties of (Ba,Ca) TiO3 Ceramics Prepared Using (Ba,Ca)TiO3 Ceramics I, Crystallographic and Microstructural Studies

Abstract: Ba[sub 1[minus]x]Ca[sub x]TiO[sub 3] powders have been prepared using a novel route involving solid-state reaction in a mixture of Ba[sub 1[minus]x]Ca[sub x]CO[sub 3] and TiO[sub 2]. The Ba[sub 1[minus]x]Ca[sub x]CO[sub 3] precursors used in this method were prepared by a chemical coprecipitation route to ensure a uniform supply of Ba and Ca ions during thermochemical reaction with TiO[sub 2]. The compositional homogeneity of Ba[sub 1[minus]x]Ca[sub x]TiO[sub 3] powder prepared by such a semiwet route is compared with those prepared by the conventional dry route, involving thermochemical reaction in a mixture of BaCO[sub 3], CaCO[sub 3], and TiO[sub 2] using principles of X-ray line broadening. It is shown that the powders obtained by the semiwet route possess better compositional homogeneity, over a length scale of 1,800 [angstrom] corresponding to the coherently scattering domain size, than those prepared by the conventional dry route. Microstructural studies have revealed grain sizes of the order of 1 [mu]m and several micrometers, respectively, for ceramics prepared by the semiwet and conventional dry routes. The solid solubility limit of Ca in Ba[sub 1[minus]x]Ca[sub x]TiO[sub 3] ceramics fired at 1,300 C is 16 mol% for samples prepared by the semiwet route while conventionally processed ceramics had a Camore » solid solubility limit of 12 mol% at the same temperature.« less