Biomedical subjects

U P Singh

Publications and source records attributed to U P Singh.

At least 19 recordsLinked to original sources

PubMed2006

Differential methods of inoculation of plant growth-promoting rhizobacteria induce synthesis of phenylalanine ammonia-lyase and phenolic compounds differentially in chickpea.

Foliar spray and micro-injection of plant growth-promoting rhizobacterial species, viz. Pseudomonas fluorescens and P. aeruginosa on chickpea induced synthesis of phenylalanine ammonia-lyase (PAL) when tested against Sclerotinia sclerotiorum. Induction of PAL was also associated with increased synthesis of phenolic compounds such as tannic, gallic, caffeic, chlorogenic and cinnamic acids. Treatment with P. fluorescens was found to be more effective in inducing phenolic compounds as compared to P. aeruginosa. However, persistence of PAL activity was observed more with P. aeruginosa. Although both the inoculation methods were effective, foliar application was found to be superior to micro-injection in terms of rapid PAL activity leading to the synthesis of phenolic compounds.

Antibiosis↗

PubMed2005

Histochemical localization of enzymes and lipids in the ovary of a vespertilionid bat, Scotophilus heathi, during the reproductive cycle.

The present study describes seasonal changes in delta5 3beta hydroxysteroid dehydrogenase (3beta-HSD), glusose-6 phosphates dehydrogenase (G-6-PD), and lipids in the ovary of a vespertilionid bat, Scotophilus heathi. Total lipids and 3beta-HSD activity are restricted to thecal and interstitial cells of the ovary. The total lipids, 3beta-HSD, and G-6-PD significantly increase during recrudescence, and remain high during winter dormancy and breeding as compared to the other reproductive phases. High incidence of lipids and enzyme activity in interstitial cells during the breeding period and at the time of ovulation clearly suggests that these cells are actively involved in steroidogenesis. A decline in enzymes and lipid activity during winter dormancy, which correlates with the declining levels of steroidogenesis, might be the factors responsible for prolonged survival of the Graafian follicle in the ovary of S. heathi.

3-Hydroxysteroid Dehydrogenases↗

PubMed2005

Phenolic acids in neem (Azadirachta indica): a major pre-existing secondary metabolites.

High Performance Liquid Chromatographic (HPLC) analyses of various parts (fresh and dry bark of stem, mature and tender leaves, flower and different parts of fruit, i.e., raw and ripe fruit epicarp, mesocarp and seed) of neem (Azadirachta indica), which occupies an important place in socio-cultural-religious life in Indian communities, indicate that neem is rich in pre-existing secondary metabolites (phenolic acids). Dry bark showed only tannic acid but in fresh bark three phenolic acids were observed, i.e., gallic, tannic, and ferulic acids. In tender leaves only gallic and ferulic acids were detected, but the levels of these phenolic acids in mature leaves were about three times and fifty times greater, respectively. Flowers had only two phenolic acids in which gallic acid was maximum followed by chlorogenic acid. The level of phenolic acid was maximum in seeds followed by epicarp and pulp. In raw and ripe fruit seeds four phenolic acids were detected. Raw fruit seeds were rich in phenolic acids than ripe fruit seeds. Fruit epicarp was relatively richer than seed, seed pulp and flowers of the plants. Neem flowers were also rich in gallic and chlorogenic acids.

Azadirachta↗

PubMed2004

Characterization of phenolic compounds in some Indian mango cultivars.

Mangoes (Mangifera indica) are rich in phenolic acids as detected by high-performance liquid chromatography. The phenolics have prominent medicinal properties. Among six important commercial mango cultivars (Deshi, Langra, Chausa, Mallika, Dashahari and Amrapali) tannic acid was maximal in Mallika, while gallic acid was maximal in Chausa and all other varieties. Caffeic acid was maximal in Langra followed by Chausa and Amrapali. Many of the pharmacological properties attributed to mango might be due to the presence of phenolic acids in fairly significant amounts.

Caffeic Acids↗

PubMed2004

Investigation on the phenolics of some spices having pharmacotherapeuthic properties.

Spices are an important group of agricultural commodities being used by many civilizations all over the world to aid flavor, taste and nutritional values in the food. In traditional medical systems, their ability to heal various physical, mental and emotional problems has widely been reported. With this view, HPLC analysis was performed to estimate phenolic acids in 21 spices (asafetida, Bishop's weed, black mustard, coriander, cinnamon, clove, curry leaf, cumin black, cumin, fennel, fenugreek, garlic, ginger, Indian cassia, Indian dill or dill large cardamom, onion, saffron, tamarind, true cardamom, yellow mustard) commonly used in India in different forms. In all, 7 phenolic acids; viz., tannic, gallic, caffeic, cinnamic, chlorogenic, ferulic and vanillic acids could be identified on the basis of their retention time with standard compounds and co-chromatography. Several parts of the spices, for instance, seeds, leaves, barks, rhizomes, latex, stigmas, floral buds and modified stems were used in the study. Maximum amount of tannic and gallic acids was observed in black mustard and clove. Caffeic, chlorogenic and ferulic acids were found maximum in cumin while vanillic and cinnamic acids in onion seeds. The spices are known to significantly contribute to the flavor, taste, and medicinal properties of food because of phenolics.

Antioxidants↗

PubMed2003

Individual and combined effect of (+/-)-alpha-hydrastine and (+/-)-beta-hydrastine on spore germination of some fungi.

(+/-)-alpha-Hydrastine and (+/-)-beta-hydrastine were isolated from Corydalis longipes; both exhibited considerable efficacy against spore germination of some saprophytic and phytopathogenic fungi. While (+/-)-alpha-hydrastine was effective against most of the fungi, Helminthosporium echinoclova was least affected even at the highest dose (150 ppm). (+/-)-beta-Hydrastine was equally effective against several fungi. Mixture of both compounds was more effective than each one individually. Helminthosporium species were again the most resistant toward the mixture. The effect of both alkaloids independently on germination and development of E. pisi conidia on excised pea leaves was also shown. After pre-inoculation with (+/-)-alpha-hydrastine, the effect was more pronounced than the addition post-inoculation; maximum inhibition occurred at 200 ppm. (+/-)-beta-Hydrastine also reduced germination of conidia but was less effective than (+/-)-alpha-hydrastine. The number of primary and secondary branches of conidia and number of appressoria were not affected significantly by either compound.

Alkaloids↗

PubMed2003

Two plant alkaloids isolated from Corydalis longipes as potential antifungal agents.

The alkaloids N-methylhydrasteine hydroxylactam and 1-methoxyberberine chloride were isolated from Corydalis longipes. Both alkaloids showed high efficacy individually (in concentration of 50-150 ppm) and also in a 1:1 mixture against spore germination of some fungi, viz. Alternaria alternata, A. brassicae, Curvularia maculans, Curvularia sp., Colletotrichum gloeosporioides, Colletotrichum sp., Helminthosporium speciferum, H. pennisetti, Helminthosporium sp., and Ustilago cynodontis. The antifungal effect of single compounds was dose-dependent. If the mutual ratio of the two components in the mixture was changed from 1:1 to a major content of any of the two compounds, the inhibitory effect on spore germination decreased.

Alkaloids↗

PubMed2002

Seasonal changes in circulating steroid concentration and their correlation with the ovarian activity in the female Indian sheath-tailed bat, Taphozous longimanus.

The relationship between ovarian activity and circulating steroid concentration was studied in the female sheath-tailed bat, Taphozous longimanus. T. longimanus breeds twice in rapid succession during the year at Varanasi, India. Ovarian recrudescence was observed during September, and antral follicles were first observed during the month of October. Circulating androstenedione concentration showed an increase beginning in October, reaching a peak in December. This increase in androstenedione concentration correlated with the period of heavy accumulation of adipose tissue and increase in body mass. Antral follicles grow slowly during the period of high circulating androstenedione concentration from October to December. There was a sharp decline in androstenedione concentration during January. Simultaneously with the decline in androstenedione concentration, a sharp increase in size of the antral follicle and circulating estradiol concentration was noticed. Soon thereafter, one of the follicles ruptures, followed by fertilization and the commencement of the first pregnancy. During the second pregnancy, antral follicles first appeared during late pregnancy in March in the contralateral ovary that lacked the corpus luteum. One follicle developed rapidly and quickly attained a preovulatory stage in April. This is reflected in a sharp increase in estradiol concentration during this period. Ovulation was observed immediately following the first pregnancy in May. During this period, androstenedione concentration remained low. The results of the present study suggest that high androstenedione concentration during October to December (winter dormancy) may be responsible for slow follicular development and delays ovulation in T. longimanus. It is further hypothesized that the geographical variation in reproductive pattern of T. longimanus could be due to variation in the duration of fat storage and associated changes in the androstenedione concentration.

Adaptation, Physiological↗

PubMed2002

Efficacy of alkaloid (-)-corypalmine against spore germination of some fungi.

Inhibition activity of the alkaloid (-)-corypalmine on spore germination of plant pathogenic and saprophytic fungi (Alternaria solani, A brassicicola, A. brassicae, A. melongenae, Curvularia pallescens, C. lunata, C. maculans, Curvularisa sp., Colletotrichum sp., Helminthosporium speciferum, H. frumentacei, H. pennisetti, Heterosporium sp., Penicillum sp., Ustilago cynodontis) was determined. Spore germination of all the tested fungi was inhibited, Heterosporium sp. and Ustilago cynodontis being the most sensitive (complete inhibition of spore germination was observed at the very low concentration of 200 ppm). Curvularia palliscens, C. maculans and Curvularia sp. were less sensitive; complete inhibition of spore germination occurred at 400 ppm.

Alkaloids↗

PubMed2002

Effect of berberine and (+/-)-bicuculline isolated from Corydalis chaerophylla on spore germination of some fungi.

Berberine and (+/-)-bicuculline were isolated from roots and leaves, respectively, of Corydalis chaerophylla. Both were effective in vitro against spore germination of some plant pathogenic fungi (Alternaria brassicicola, A. brassicae, A. cheiranthi, A. melongenae, A. solani, Colletotrichum musae, C. falcatum, Curvularia penniseti, C. lunata, C. maculans, C. pallescens, Curvularia sp., Erysiphe pisi, E. cichoracearum, Erysiphe sp., Fusarium udum, Helminthosporium spiciferum, H. penniseti, H. frumentacei, Heterosporium sp., Oidium erysiphoides and Ustilago cynodontis). Berberine and (+/-)-bicuculline significantly inhibited spore germination of all the fungi at concentrations of 100-1000 ppm. Berberine was effective against all the fungi at all concentrations; most of the fungi did not germinate at 1000 ppm. H. penniseti conidia did not germinate at any concentration of (+/-)-bicuculline. U. cynodontis was the least sensitive fungus at lower concentrations but 800 ppm dose was highly effective.

Antifungal Agents↗

PubMed2002

Plant growth-promoting rhizobacteria-mediated induction of phenolics in pea ( Pisum sativum) after infection with Erysiphe pisi.

Qualitative and quantitative estimation of phenolic compounds was done through high performance liquid chromatography (HPLC) in different parts of pea ( Pisum sativum) after treatment with two plant growth-promoting rhizobacteria (PGPR), viz., Pseudomonas fluorescens (strain Pf4) and Pseudomonas aeruginosa (referred to here as Pag) and infection by Erysiphe pisi. The phenolic compounds detected were tannic, gallic, ferulic, and cinnamic acids on the basis of their retention time in HPLC. In all the treated plants, synthesis of phenolic compounds was enhanced. The induction of gallic, ferulic, and cinnamic acids was manyfold more than those in the control. Maximum accumulation of phenolic compounds was observed in plants raised from PGPR-treated seeds and infection with E. pisi. Under pathogenic stress, Pag performed better because a relatively higher amount of phenolics was induced compared with plants treated with Pf4.

Ascomycota↗

PubMed2002

Studies on exudate-depleted sclerotial development in Sclerotium rolfsii and the effect of oxalic acid, sclerotial exudate, and culture filtrate on phenolic acid induction in chickpea (Cicer arietinum).

Exudate depletion from developing sclerotia of Sclerotium rolfsii Sacc. in culture caused reduced size and weight of sclerotia. Germination of exudate-depleted sclerotia was delayed on Cyperus rotundus rhizome meal agar medium when compared with that of control sclerotia. The exudate-depleted sclerotia caused infection in chickpea (Cicer arietinum) plants in a glasshouse. Different temperatures and incubation periods had no effect on the germination ability of the exudate-depleted sclerotia. Oxalic acid, sclerotial exudate, and culture filtrate of S. rolfsii induced the synthesis of phenolic acids, including gallic, ferulic, chlorogenic, and cinnamic acids, as well as salicylic acid, in treated chickpea leaves. Gallic acid content was increased in treated leaves compared with the untreated controls. Maximum induction of gallic acid was seen in both leaves treated with oxalic acid followed by exudate and leaves treated with culture filtrate. Cinnamic and salicylic acids were not induced in exudate-treated leaves. Ethyl acetate fractionation indicated that the sclerotial exudates consisted of gallic, oxalic, ferulic, chlorogenic, and cinnamic acids, whereas the culture filtrate consisted of gallic, oxalic, and cinnamic acids along with many other unidentified compounds.

Basidiomycota↗

PubMed2002

Seasonal changes in thyroid activity in the female sheath-tailed bat, Taphozous longimanus (Chiroptera: Emballonuridae).

The present study was designed to investigate changes in thyroid activity during the reproductive cycle in Taphozous longimanus. Thyroid gland showed marked seasonal variation in weight and secretory activity. It was inactive in quiescence and early to mid-winter dormancy and active during recrudescence and breeding period during late winter dormancy. The serum 3,5,3'-triiodothyronine (T3) and thyroxine (T4) concentrations showed significant variation and closely coincided with thyroid activity. The T3 and T4 concentrations were higher in recrudescence, late winter dormancy and minimum in quiescence and initial stages of first pregnancy. The body weight (r = 0.56), ovary weight (r = 0.73), and thyroid weight (r = 0.70) showed correlation with each other and with T3 and T4 concentrations. The correlation between body weight, thyroid weight and T3 and T4 concentrations in non-pregnant bats was higher when compared with pregnant bats. The T3 and T4 levels remained low during the initial stages of development in first pregnancy when compared with the initial stages of second pregnancy. The scant food supply and low levels of T3 and T4 and low temperature during initial stages of first pregnancy might be responsible for differential rate of fetal development in two successive pregnancies in T. longimanus.

Animals↗

PubMed2001

Individual and combined effects of berberine and santonin on spore germination of some fungi.

Berberine and santonin were isolated from rhizomes of Berberis aristata and unexpanded flower buds of Artemisia maritima, respectively. Efficacy of these two chemicals individually as well as of their mixtures, was tested against spore germination of some saprophytic and obligate fungi. While berberine individually was effective against most of the fungi, Helminthosporium spp. were least affected even at the highest dose (1500 ppm). Santonin was equally effective against several fungi. Mixture of both alkaloids found to be more effective than individual ones. Keeping the dose of berberine constant and santonin at two different concentrations (viz. 250 and 500 ppm) the spore germination of Helminthosporium oryzae was stimulated. Increasing concentration of santonin inhibited the spore germination of all other fungi tested, Colletotrichum capsici being affected only by 20 and 5% (at berberine concentration of 250 and 500 ppm, respectively). On the other hand, santonin being constant and berberine at different concentrations, the mixture was effective against all the fungi.

Artemisia↗

PubMed2001

Effect of calcium and calmodulin modulators on the development of Erysiphe pisi on pea leaves.

The effect of calcium and calmodulin modulators, viz., ethylene glycol bis (beta-amino ethyl ether)-N,N,N',N'-tetraacetic acid (EGTA), a calcium chelator; verapamil, a plasma membrane Ca2+ channel blocker; ruthenium red, an organelle Ca2+ channel blocker; and chlorpromazine, a calmodulin antagonist; on the development of Erysiphe pisi was studied by floating the inoculated leaves on the respective solutions of chemicals. All the modulators affected the development of E. pisi by inhibiting the colony diameter, number of secondary branches, number of hyphal cells per colony and number of haustoria. The calmodulin antagonist was more effective in reducing E. pisi development. The results suggest the possible involvement of calcium and calmodulin in the development of E. pisi on pea leaves.

Ascomycota↗

PubMed2001

Role of garlic (Allium sativum L.) in human and plant diseases.

A resurgence of interest in garlic due to recent revelations of its beneficial effects in the treatment of various human and plant diseases and also due to validation of claims made in traditional systems of medicine has resulted a plethora of publications on different aspects of garlic in recent years. Chemical constituents of garlic and their variations on the methods of isolation have been discussed in the present review. Effect of garlic and its constituents against various human and plant pathogenic and saprophytic microorganisms has also been reviewed.

Animals↗

PubMed2000

Seasonal changes in circulating testosterone and androstenedione concentration and their correlation with the anomalous reproductive pattern in the male indian sheath-tailed bat, Taphozous longimanus.

The relationship between reproductive organs, circulating testosterone, and androstenedione concentration in the male sheath-tailed bat, Taphozous longimanus, was studied. The masses of testis, accessory sex gland (prostate, ampullary), and epididymides showed three peaks, one each in October, January, and April. Monthly changes in testosterone also peaked during October, January, and April and closely coincided with the peak spermatogenesis. Serum androstenedione concentration peaked during November and January. Testosterone showed a strong correlation with masses of testis and accessory sex glands, while androstenedione showed strong correlation with the body mass. Different threshold levels of testosterone may be required to trigger spermatogenesis, secretory activity of accessory sex glands and mating in Taphozous longimanus and may be responsible for reproductive asynchrony in this species. Higher circulating concentrations of testosterone and androstenedione throughout the year in this species, as compared with other mammalian species, may be responsible for prolonged retention of sperm in the epididymides.

Androstenedione↗

PubMed2000

Antifungal activity of venenatine, an indole alkaloid isolated from Alstonia venenata.

The indole alkaloid venenatine exhibited antifungal activity against some plant pathogenic and saprophytic fungi. Venenatine in an aqueous acetic acid solution inhibited spore germination of all the 10 tested fungi, Fusarium udum, Alternaria brassicicola, Ustilago cynodontis and Aspergillus flavus showed an especially high sensitivity towards this compound, exhibiting germination levels below 10%. The spore germination and colony development of the parasitic fungus Erysiphe pisi, which causes powdery mildew in pea (Pisum sativum), on excised leaves of pea was also significantly affected. Pre-inoculation rather than post inoculation treatment of the leaves was more inhibitory against spore germination and colony development.

Alkaloids↗