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.

Genotoxic effect of raw betel-nut extract in relation to endogenous glutathione levels and its mechanism of action in mammalian cells.

Abstract: The mutagenic and carcinogenic potency of betel-nut components is well established. This study was undertaken to determine the genotoxic potency of an aqueous extract of raw betel nut (AEBN) in relation to the endogenous glutathione (GSH) level in mouse bone marrow cells (BMC) and human peripheral blood lymphocytes (PBLs), and to find out whether arecoline (ARC), an alkaloid of betel nut, could generate reactive oxygen species (ROS) in these cells. It was observed that AEBN has genotoxic properties, which is further enhanced by depletion of endogenous GSH levels. However, the degree of enhancement varies with the type of parameter and cell system studied. The present data indicate that the generation of ROS by ARC could partially contribute to the induction of chromosomal aberrations (CAs), since the frequency of ARC-induced CAs was reduced either by post-treatment with superoxide dismutase (SOD) or in anoxic conditions. However, the induction of sister chromatid exchanges (SCEs) probably involves p53-dependent changes in cell proliferation and allowing some repair of DNA damage. The extent of damage for each parameter was higher when the mice were exposed to AEBN for 30 days than 5 days. Longer exposure showed higher level of p53 expression in mouse BMC, which could block the damaged cells from proliferation and allow the cells to repair the DNA damage.

Herbaceous vegetation development and weed potential in slash and burn agriculture (Jhum) in N. E. India

Abstract: Summary The patterns of herbaceous vegetation development and weed potential following slash and burn clearing after different lengths of time between the cultivation cycles are described. The early stages of secondary succession following burning tended to conform closely to the ‘initial floristic compositione’ model under shorter cycles of 4 and 6 years between cultivation, but the ‘relay floristicse’ model was found to be more applicable to the cycles of 10 and 20 yearse’ duration. Weed population, in terms of density, biomass and germinable seeds present in the soil, was significantly higher after cycles of 4 and 6 years compared to 10- and 20-year cycles. In all the cycles, however, weed population declined sharply after a year of cropping with an effective weeding programme following the burn. Rasuma Evolution des adventices herbacees en culture sur brulis (Jhum) au nord est des Indes Les tendances observees dans le developpement de la vegetation herbacee et de son potential en tant que mauvaises herbes suivant culture sur brulis sont decrites. Les etapes precoces de la succession secondaire apres brulis ressemblaient d'assez pres au modele ‘composition floristique initialee’ dans les cycles plus courts, c'est-a-dire de 4 et 6 ans entre cultures; mais pour les cycles d'une duree de 10 et 20 ans le modele ‘floristique de relaise’ semblait plus approprie. Le peuplement de mauvaises herbes, considere en fonction de la densite, de la biomasse et des graines capables de germer presentes dans le sol, etait significativement superieur apres des cycles de 4 et 6 ans par rapport aux cycles de 10 et 20 ans. Cependant dans tous les cycles le peuplement diminuait rapidement au bout d'un an de culture qui comprenait un desherbage effectif apres le brulis. Zusammenfassung Entwicklung des staudenartigen Pflanzenwuchs und dessen Unkrautspotential in der Brandwirtschaft (Jhum) Nordostindiens Das Bild der Entwicklung von staudenartigen Pflanzen und deren Unkrautspotential in einer Brandwirtschaft werden mit Bezug auf verschiedene Zeitabstande zwischen den Anbauperioden beschrieben. Die fruhen Etappen der sekundaren Sukzession nach dem Brand neigten bei den kurzeren Zeitabstanden mit 4 und 6 Jahren zwischen den Anbauperioden dem Modell ‘floristichen Anfangskompositione’ zu. Das Modell ‘Staffelfloristike’ aber erwies sich als den Zyklen mit 10- und 20-jahrigen Zeitabstanden mehr geeignet. Die Unkrautpopulation, als Dichte. Biomasse und keimfahige Samen im Boden ausgedruckt, lag bedeutend hoher nach 4- und 6-jahrigen, im Vergleich mit 10- und 20-Jahrigen Zeitabstanden. In allen Zyklen aber geschah eine starke Minderung der Unkrautpopulation nach Anbau wahrend eines Jahrs, wo ein erfolgreiches Unkrautbekampfungsprogramm nach dem Brand durchgefuhrt wurde.