North Eastern Hill University

About: North Eastern Hill University is a education organization based out in Shillong, Meghalaya, India. It is known for research contribution in the topics: Population & Catalysis. The organization has 2318 authors who have published 4476 publications receiving 48894 citations.

Surface-modified CdS nanoparticles as a fluorescent probe for the selective detection of cysteine.

Abstract: We present a novel method for the selective detection of cysteine, a sulfur-containing amino acid, which plays a crucial role in many important biological functions such as protein folding. Surface-modified colloidal CdS nanoparticles have been used as a fluorescent probe to selectively detect cysteine in the presence of other amino acids in the micromolar concentration range. Cysteine quenches the emission of CdS in the 0.5?10??M concentration range, whereas the other amino acids do not affect its emission. Among the other amino acids, histidine is most efficient in quenching the emission of the CdS nanoparticles. The sulfur atom of cysteine plays a crucial role in the quenching process in the 0.5?10??M concentration range. Cysteine is believed to quench the emission of the CdS nanoparticles by binding to their surface via its negatively charged sulfur atom. This method can potentially be applied for its detection in biological samples.

Multiple shoot induction from axillary bud cultures of the medicinal orchid, Dendrobium longicornu.

Abstract: Background and aims Dendrobium longicornu, commonly known as the ‘Long-horned Dendrobium’, is an endangered and medicinally important epiphytic orchid. Over-exploitation and habitat destruction seriously threaten this orchid in Northeast India. Our objective was to develop an efficient protocol for the mass propagation of D. longicornu using axillary bud segments. Methodology and principal results Axillary buds cultured in Murashige and Skoog semi-solid medium supplemented with a-naphthalene acetic acid (NAA), 2,4-dichlorophenoxy acetic acid (2,4-D) and 6-benzylaminopurine (BAP) readily developed into plantlets. These formed either directly from shoot buds or from intermediary protocorm-like bodies (PLBs). The maximum explant response (86.6 %) was obtained in medium supplemented with NAA at 30 mM, while the maximum number of shoots (4.42) and maximum bud-forming capacity (3.51) were observed in medium containing 15 mM BAP and 5 mM NAA in combination. Protocorm-like bodies were obtained when the medium contained 2,4-D. The maximum number of explants forming PLBs (41.48 %) was obtained in medium containing 15 mM BAP and 15 mM 2,4-D. Well-developed plantlets obtained after 20 –25 weeks of culture were acclimatized and eventually transferred to the greenhouse. Over 60 % of these survived to form plants � 3 – 4 cm tall after 90 days in glasshouse conditions using a substrate of crushed brick and charcoal, shredded bark and moss. Conclusions The method described can readily be used for the rapid and large-scale regeneration of D. longicornu. Its commercial adoption would reduce the collection of this medicinally important and increasingly rare orchid from the wild.

Efficacy of Lasia spinosa leaf extract in treating mice infected with Trichinella spiralis

Abstract: Trichinellosis is a widespread zoonoses for which no effective drug treatment is available at this time. Though anthelmintics such as mebendazole and albendazole are commonly used to treat human trichinellosis, none of these drugs are fully effective against the encysted or new-born larvae of Trichinella spiralis. In recent years, there has been a growing interest in developing newer anthelminthics from medicinal plants, particularly the ones used in traditional medicines in many parts of the world, due to the increasing spread of anthelminthic resistance and/or decreasing activity against encapsulated larval stages of parasites. The aim of the present study was to investigate the efficacy of leaf extract of Lasia spinosa (Araceae) against different life cycle stages of T. spiralis, i.e. adult (days 3 and 4 post-infection), migrating larvae (days 8, 9 and 10 post-infection) and encysted muscle larvae (days 31–37 post-infection). The study showed that L. spinosa leaf extract is effective against all the three life cycle stages of parasite. Against the adult stage, an oral administration of plant extract at 800 mg/kg dose revealed a 75.30% reduction in the number of adult worms, as compared to untreated controls at day 10 post-infection. Whereas against migrating larvae, the same dose of plant extract given for 3 days, reduced the number of larvae recovered from musculature of treated animals by 72.23%. However, in comparison of preceding two stages, the extract showed comparatively less efficacy against the encysted larvae of parasite. In this case, the 800 mg/kg dose of extract given for 7 days (after 30 day of post-infection) revealed only 64.84% reduction in the number of encysted larvae, as was evident from larval count on day 49 post-infection. Therefore, the results of this study indicate that leaf extract of L. spinosa possesses significant anthelminthic efficacy against the adult stages and migrating larvae of T. spiralis. On the other hand, the encysted muscle larvae of parasite are comparatively less sensitive to L. spinosa leaf extract treatment.

Actinobacterial diversity in limestone deposit sites in Hundung, Manipur (India) and their antimicrobial activities

Abstract: Studies on actinobacterial diversity in limestone habitats are scarce This paper reports profiling of actinobacteria isolated from Hundung limestone samples in Manipur, India using ARDRA as the molecular tool for preliminary classification A total of 137 actinobacteria were clustered into 31 phylotypic groups based on the ARDRA pattern generated and representative of each group was subjected to 16S rRNA gene sequencing Generic diversity of the limestone isolates consisted of Streptomyces (15 phylotypic groups), Micromonospora (4), Amycolatopsis (3), Arthrobacter (3), Kitasatospora (2), Janibacter (1), Nocardia (1), Pseudonocardia (1) and Rhodococcus (1) Considering the antimicrobial potential of these actinobacteria, 19 showed antimicrobial activities against at least one of the bacterial and candidal test pathogens, while 45 exhibit biocontrol activities against at least one of the rice fungal pathogens Out of the 137 actinobacterial isolates, 118 were found to have at least one of the three biosynthetic gene clusters (PKS-I, PKS-II, NRPS) The results indicate that 86% of the strains isolated from Hundung limestone deposit sites possessed biosynthetic gene clusters of which 40% exhibited antimicrobial activities It can, therefore, be concluded that limestone habitat is a promising source for search of novel secondary metabolites