Narayan Ghorai

Protective effect of Croton caudatus Geisel leaf extract against experimental visceral leishmaniasis induces proinflammatory cytokines in vitro and in vivo.

In the present state of overwhelming emergence of drug-unresponsive phenotypes of Leishmania donovani and persistent severe toxicity in conventional anti-leishmanial therapy, in search for novel leads, the aim of this study has been fixed to identify the active extract(s) of Croton caudatus Geisel. var. tomentosus Hook effective against the parasitic protozoans in vitro and in vivo. C. caudatus Geisel. is often used by Chakma and Hmar community, the local tribes of north-east India for medicinal and veterinary purposes. Among the five semi-purified extracts tested, C. caudatus leaves, extracted in hexane and subsequently semi-purified in a column packed with silica gel (70-130 µM; mesh size 60 A°) using ethyl acetate-hexane solvent (9:1), was found to be the most effective growth inhibitor (JDHex) against the Leishmania promastigotes and amastigotes. JDHex significantly altered the biochemical parameters (protein, lipid and carbohydrates) in promastigotes followed by the morphological changes, DNA condensation and subsequent apoptosis in L. donovani. In consequent steps, it has been also proved that JDHex reduced the replication of intracellular amastigotes with concomitant release of nitric oxide and pro-inflammatory cytokines, IL-12 and TNF-α in vitro. Significantly, the 50% inhibitory concentration of JDHex was estimated much lower against the intracellular amastigotes (2.5 µg/mL) in comparison to promastigotes (10 µg/mL). JDHex was also found efficient in reducing parasite burden in spleen and liver when treated in vivo and increased the intracellular IFN-γ and decreased the IL-10 in CD4+ T cells in splenocytes of orally treated animals. The results of this study support the importance in exploration of novel anti-leishmanial leads from C. caudatus Geisel. var. tomentosus Hook. against the L. donovani (MHOM/IN/83/AG83) infection. Partial chemical characterization of JDHex revealed the presence of terpenoids. However, the further chemical investigation of JDHex is warranted.

Study on the selection of some local pollen plants in West Bengal, India as pollen brood feed in Apis cerana Fabr. Larvae by the worker bees, through meconia analysis and community ordination method of recovered pollen taxa

Pollen analytical data of meconia from worker bee larvae of Apis cerana Fabr. collected in the summer (June, 2008) from West Bengal, India (22.35°N, 88.44°E) are presented. Following the community ordination method, the pollen analytical data were used to determine the preference of pollen feeding by the worker bees to the larvae destined to be worker of Apis cerana, which could be recognized as a new protocol in order to ascertain the probable larval food spectrum. Meconium samples were collected from 9 different sites having box hives. Microscopic analysis yields pollen grains of 10 different taxa viz., Carica papaya L. (Caricaceae), Borassus flabellifer L., Cocos nucifera L. (Arecaceae), Psidium guajava L., Eucalyptus sp., Syzygium sp., (Myrtaceae), Punica granatum L. (Punicaceae), Litchi chinensis Sonn. (Sapindaceae), Ziziphus sp. (Rhamnaceae) and Dalbergia sissoo Roxb. ex DC. (Papilionaceae). The community ordination method reveals that the most preferred pollen taxa are of Carica papaya, Borassus flabellifer and Psidium guajava although they were not recovered in significant frequency. The present result may be an useful information for the apiarists, especially during site selection for hive installation.

Food preference and foraging of fire ant Solenopsis nitens

Experiments were carried out to note the preference of food viz. carbohydrate (sucrose, glucose, and fructose), saturated fat, unsaturated fat and protein (dead cockroach) by a breeding colony of Solenopsis nitens. The ants showed an increasing preference for liquid foods (glucose, sucrose, fructose, saturated fat, unsaturated fat) during initial 7–8 consecutive days of studies. In the next four consecutive days there was an increase in the preference for solid food (animal protein). The ascending order of preference of liquid food items was glucose, sucrose, fructose, unsaturated fat, and saturated fat respectively. A distinct trailing pattern of foraging was observed on placing the food item beyond a distance of 20 cm from the nest site. The length of these trails increased with the increasing distance of the nest site from the food item. The active period of foraging was confined to 15:00 hours to 8:00 hours.

Activity of Some Selected Hydrolases in Worker Honey Bees, Apis cerana (Fabr.). [Apidae:Insecta]

Abstract An API ZYM (Bio-Merieux, Lyon, France) test kit was used to examine the activity 19 hydrolases in in-hive bees and out-hive bees of worker Apiscerana. The study indicated that the activity of enzymes was changing in hypopharyngeal gland in in-hive and out-hive worker bees distinctly. The activities of most of the enzymes were observed. The protein hydrolases (acidic hydrolases) viz. leucine arylamidase, and valine arylamidase were more active in in-hive bees than out-hive bees. Rest of the tested enzymes were moderately present both in in-hive and out-hive bees. The hypopharyngeal gland and their secretion play important role affecting digestion of pollen, lipids and carbohydrates.

Animal Interaction with Pteridophytes with Emphasis on Indian Records

Animal interaction with pteridophytes is not a common phenomenon. Most of the earlier records come from Europe, America and Java. The present article deals with the records of animal interaction with pteridophytes from India. Animal interaction with fourteen pteridophytic taxa under eight families is reported. A broad spectrum of insects, viz., Coleoptera, Diptera, Lepidoptera, Hymenoptera, Orthoptera and Hemiptera in addition to mites and gastropods were found interacting with their pteridophytic hosts. Chewing, scraping, sap sucking and galling are the presently recorded modes of animal interaction.

Selective in vitro inhibition of Leishmania donovani by a semi-purified fraction of wild mushroom Grifola frondosa

The current study was designed to assess the anti-leishmanial effect of a semi-purified fraction of wild mushroom Grifola frondosa against Leishmania donovani, in vitro. A total of five extracts from three wild mushrooms [Grifola frondosa (family, Meripilaceae) Laetiporus sulphurous (family, Polyporaceae) and Meripilus giganteus (family, Meripilaceae) were explored for novel anti-leishmanial leads against promastigotes. The ethanol extract of G. frondosa was selected as the most efficient against L. donovani promastigotes (IC50: 93.9 μg/mL). A semi-purified fraction was obtained from an active ethanol extract of G. frondosa and found to inhibit the survival of promastigotes of L. donovani (MHOM/IN/83/AG83) significantly (IC50: 20.37 μg/mL) and it also had some effect against L. major LV39 (MRHO/Sv/59/P strain) and L. tropica WR683 (MHOM/SU/58/OD) strains at higher concentrations (IC50: 46.08 μg/mL and 53.79 μg/mL respectively). The semi-purified fraction also interfered in lipid biosynthesis, altered parasite morphology and induced apoptosis in L. donovani promastigotes. The semi-purified fraction was also effective against intracellular amastigotes in infected macrophages and enhanced the release of nitric oxide and pro-inflammatory cytokines, in vitro. Interestingly, the 50% inhibitory concentration of the semi-purified fraction against the intracellular amastigotes (IC50: 2.48 μg/mL) was much lower in comparison to promastigotes (IC50: 20.37 μg/mL). The semi-purified fraction was found to inhibit the intracellular amastigotes slightly more efficiently in comparison to conventional anti-leishmanial drugs; sodium antimony gluconate, amphotericin B, miltefosine and paromomycin and noticeably non-toxic towards host splenocytes. The findings of the present study established that G. frondosa might be a natural resource for development of a new anti-leishmanial lead.

Behavioural ecology of a tea pest, Andraca bipunctata (Lepidoptera: Bombycidae), in the Sub-Himalayan climate of Darjeeling (India)

Behavioural ecology of a tea pest, Andraca bipunctata (Lepidoptera: Bombycidae), in the Sub-Himalayan climate of Darjeeling (India) The summer generation (G1) of Andraca bipunctata Walker in Darjeeling was confined to May-December and the winter generation (G2) extended from August to June. One female laid on average 480 and 526 eggs in G1 and G2, respectively. Larvae fed on Camellia sinensis and C. assamica leaves. Duration of 1st, 2nd, 3rd, 4th and 5th instars were 7, 7, 6, 6 and 6 days in G1, and 20, 20, 24, 72 and 33 days in G2, respectively. Temperature seems to greatly influence the duration of its life stages. A fungus (Paecilomyces tenuipes Samson), garden lizard Calotes versicolor (Daudin), and several bird species (Stachyris nigriceps Blyth, Spelaeornis caudatus (Blyth) and Dendrocitta frontalis Horsefield) were found effective in reducing the population of A. bipunctata.