Antifungal activity of the stem bark of Ailanthus excelsa

The methanol extract of stem barks of Alianthus excelsa was partitioned with chloroform. The chloroform extract showed fungistatic and fungicidal activity against Aspergillus niger, A. fumigatus, Penicillium frequentence, P. notatum and Botrytis cinerea.     

An Oxidative Mechanism for the Inhibition of Iodothyronine 5′-Monodeiodinase Activity by Lead Nitrate in the Fish,Heteropneustes fossilis

An oxidative mechanism in the lead-induced inhibition of thyroid function with special reference to iodothyronine 5′- monodeiodinase (5′-ID) activity has been identified in the fish, Heteropneustes fossilis. Lead treatment (2.5, 5.0 and 10.0 ppm of lead nitrate/day for 30 days) enhanced tissue lipid peroxidation (LPO) and decreased the activity of antioxidant enzymes such as superoxide dismutase (SOD) and catalase (CAT). In addition, serum triiodothyronine (T3) concentration and hepatic 5'-ID activity were markedly decreased by 10 ppm of lead nitrate. These findings support the view that higher concentrations of lead nitrate inhibit the extrathyroidal conversion of thyroxine (T4) to T3. Moreover, oxidative stress from lead intoxication could be responsible for inhibiting 5′-ID activity.     

Diversity of arbuscular mycorrhizal fungi associated with the rhizosphere of tea growing in ‘natural’ and ‘cultivated’ ecosites

The colonization and diversity of arbuscular mycorrhizal fungi (AMF) associated with the rhizosphere of tea [Camellia sinensis (L.) O. Kuntze] growing under ‘natural’ as well as ‘cultivated’ conditions in the Kumaun region of Uttaranchal Himalaya (India), during the periods of active growth and dormancy were investigated. Root and rhizosphere soil samples, collected from both the ecosites (natural and cultivated), were monitored for root colonization. While the percent root colonization was quite high (77.66 ± 4.40 and 86.40 ± 3.02%, in the natural and cultivated tea, respectively) during the period of active growth in both the ecosites, relatively higher colonization (97.33 ± 0.78 and 98.13 ± 0.80%, in the natural and cultivated tea, respectively) was recorded during the period of dormancy. The rhizosphere of cultivated tea bushes was found to be dominated by Glomus morhpotypes (88.89% of the total isolates) along with three morphotypes of Acaulospora; occurrence of 35 morphotypes belonging to four genera viz. Acaulospora (11.43%), Gigaspora (11.43%), Glomus (68.57%) and Scutellospora (8.57%) was recorded in the rhizosphere of tea plants from the natural ecosite. A total of 51 AMF morphotypes were detected. Shannon–Weaver index of diversity was higher (1.80 ± 0.13 and 2.05 ± 0.10 during periods of active growth and dormancy, respectively) at the species level for the natural ecosite over its counterparts from the cultivated ecosite. Values for the diversity indices of natural and cultivated ecosites did not show much variation in the period of dormancy. These data suggest that collectively, various cultural practices negatively affect AMF diversity at the genus level in tea plantations of the colder regions.     

Genetic resources of wild edible plants and their uses among tribal communities of cold arid region of India

This paper analyzes the diversity, consumption and gathering patterns, and uses of wild edible plants among the tribal communities living in cold arid region of Indian Himalaya. Eco-geographically, extremely cold climate, open vegetation, strong afternoon winds and loose soils characterize the region. Wild edible plants have special significance in the livelihoods of tribal people particularly during harsh winters when nothing grows on field. We gathered information on 164 wild edible plant species belonging to 100 genera and 37 families sharing 14% of total plants species occurring here. Around 83% plant species were present in pure wild state while 17% were in semi wild state/cultivated occasionally. Wild plants are eaten more as vegetable and it was found that out of 101 plants used as vegetable, 57 are cooked and eaten and the rest (44) eaten raw. The species like Pinus gerardiana, Prunus armeniaca, Hippophae rhamnoides, Bunium persicum are harvested more for commerce in the downtown markets while Lepidium latifolium, Taraxacum officinale, Urtica hyperborea, Capparis spinosa, Fagopyrum tataricum, Malva verticillata, and Rhodiola heterodonta are preferred for their medicinal and nutritional properties locally. Infrastructure development, more tourists flow, agricultural intensification, more jobs and business opportunities have led to rapid changes in the life styles and food habits of the people. Consequently, the age-old tradition of gathering wild edible plants is fading particularly among younger generations. Nevertheless, people do realize the importance of wild edible plants, and therefore to harness the benefits of this unique diversity participatory management and conservation programs, investigations on nutritional and pharmacological attributes, and regulated market support for some important WEPs have taken up in the region.     

Resistance to foliar blight of wheat: A search

One thousand three hundred and eighty-seven spring wheat germplasm (Triticum aestivum L.) lines belonging to the Indian and CIMMYT wheat programmes were evaluated for their tolerance to foliar blight disease for three consecutive years i.e., from 1994 to 1997. Disease severity at six different growth stages, beginning from tillering to late milk stage, was recorded. None of the genotypes showed immunity to the disease. Of 43 lines showing resistant reaction, a major proportion (25) was represented by CIMMYT material. Comparatively, Indian germplasm lines tended to be more susceptible at more advanced growth stages. Area Under Disease Progress Curve (AUDPC) and Apparent Infection Rate (r) values of resistant lines were much lower than those of susceptible ones, but lower AUDPC in some of the resistant lines did not correspond to a lower 'r' value. Most of the resistant lines were derived from Seri, Myna, Bau, kauz, Hork 's' and Aegilops tauschii Coss.     

Cadmium Induced Inhibition of Type-I Iodothyronine 5′-monodeiodinase in Young Cockerel: The Possible Involvement of Free Radicals

The possible involvement of free radicals in the cadmium-induced thyroid dysfunction with special reference to hepatic type-I iodothyronine 5′-monodeiodinase (5′-D) enzyme activity has been studied in cockerels. Cadmium chloride (CdCl₂) administration (i.m. 0.5, 1.0 and 2.0 mg/kg body weight for 30 days) enhanced hepatic lipid peroxidation (LPO) but, decreased 5′-D activity and serum triiodothyronine (T₃) concentration. Serum thyroxine (T₄) was decreased only by the highest dose indicating that cadmium (Cd) is thyroid inhibitory only at higher doses. Liver appears to be highly sensitive to the metal as disruption of membrane configuration evidenced by increased hepatic LPO and inhibition of 5′-D enzyme activity were observed by all the three doses. We suggest that, Cd-induced inhibition of extrathyroidal conversion of T₄ to T₃, the major source of the generation of latter hormone, is dose dependent and the free radicals generated due to Cd intoxication could be one of the mechanisms involved in the inhibition 5′-D activity in hepatic tissues.