Volume 13, Issue 1, 2013 January-March

Volume 13, No 1 Pages:
2013 January-March Articles: 6

On DNA methylation: an introductory review

DNA methylation is an epigenetic phenomenon whereby a methyl (-CH3) group is added to cytosine. There are two basic types of methylation: hypomethylation in which the level of DNA methylation is greatly reduced, and hypermethylation in which there is an increased level. A methyl group is added and removed by DNA methyltransferases (DNMTs) and DNA demethylases respectively. The methyl group is transferred from a universal methyl donor S-adenosyl methionine. DNA hypermethylation in the promoter element can repress gene expression and therefore is crucial for a wide range of cellular activities such as genome stability and protection, imprinting, X-chromosome inactivation, paramutation, tissue specific gene regulation, carcinogenesis and aging. Global DNA hypomethylation has been known to play significant role in carcinogenesis. Studies in the field of DNA methylation have yielded promising potential disease biomarkers in terms of therapeutic functions. It has been concluded that the possible utilization of the degree of DNA methylation of specific genes as biomarkers for the prognosis and diagnosis of diseases is a matter which demands consideration for researchers all over the world. Canonical information on DNA methylation is highlighted in this review.

Photoemission study from Si and GaAs using a spatially varying vector potential

Photoemission calculations in the case of semiconductors like gallium arsenide (GaAs) and silicon (Si) using a spatially dependent vector potential is presented here. The logarthmic dielectric model of Gurung and Thapa is used for the calculation of vector potential. The vector potential thus developed is used for the calculation of photocurrent for which Kronig-Penney potential has been used to define the crystal potential from which the initial state wave-function for the surface state is derived.

Micro-level landslide hazard zonation of Serchhip town, Mizoram, India, using high resolution satellite data

Landslide has been one of the major geo-environmental problems in the hilly regions such as Mizoram. It is the most frequent and disruptive natural hazard to which Serchhip town is exposed. Owing to its frequent occurrence, loss of human lives and properties due to landslide are quite common amongst the residents. Although, landslides occur naturally, most of its causes can be attributed to unplanned activities on sites that are susceptible to its occurrence. Such areas are commonly found within the urban complexes where increasing population growth has necessitated the expansion of various infrastructural amenities and constructions are done without proper consideration of site safety and feasibility. Considering the present scenario, this study has been taken up to investigate the landslide hazard zonation (LHZ) of Serchhip town using high resolution satellite data. Various thematic layers, namely, slope morphometry, geological structures like faults and lineaments, lithology, geomorphology and land use/land cover were generated using remote sensing data and geographic information system (GIS). The weightage rating system based on relative importance of various causative factors is used on the different classes of thematic layers. The classes were assigned the corresponding rating value as attribute information in the GIS environment. Each class within a thematic layer was assigned an ordinal rating from 0 to 10. Summation of these attribute value were then multiplied by the corresponding weights to yield the different zones of landslide hazard. A landslide hazard zonation map was prepared showing five different zones which can assist in decision making during the pre-disaster management processes and the development of mitigation strategies.

Ethno-medicinal practices among the Mizo ethnic group in Lunglei district, Mizoram

The present study is an attempt to document the traditional practice and knowledge of medicines/naturopathy among the Mizo ethnic group of Lunglei district, Mizoram. A total of 82 medicinal plant species belonging to 42 families and 76 genera, as well as 17 animal species was documented along with their parts used, methods of preparation and types of ailments treated. The present study revealed that there is a positive relationship between age and traditional knowledge and practice; while a negative relationship between educational level and traditional knowledge and practice was observed. Ethno-medicinal knowledge and practices of the Mizo and the medicinal plant species are under serious threat due to various factors. Therefore, urgent attention towards their conservation and sustainable utilization is needed.

Anopheline diversity in Undivided Aizawl district of Mizoram, India

Mizoram is designated as high malaria endemic area by the National Vector Borne Disease Control Programme (NVBDCP) in India. The status, diversity and the number of vectors and potential vectors within Mizoram are poorly studied. This study identified 16 Anopheles species, out of which 12 are potential vectors of malaria in undivided Aizawl district of Mizoram. There are 4 species identified form the sub-genus Anopheles and 12 species from the sub genus Cellia. The result also indicates that Champhai district have the lowest anopheline diversity and Mamit district the highest. The role of each vector and potential vectors of malaria has to be further investigated.

Study on economic feasibility of intercropping of lemon (Citrus limon Burm) with vegetables in the hilly terrain of Mizoram

An experiment was carried out to study the production potential and economic feasibility of intercropping lemon and vegetable crops. The productivity of the intercropping systems was found to differ significantly. The highest gross return was obtained from the lemon + French bean intercropping system and the lowest gross return was obtained from sole lemon for two years in a row. The highest benefit - cost ratio was recorded in lemon + French bean intercropped (3.94), followed by T7 (3.70) and T4 (3.54). From the present investigation, it was apparent that the lemon + French bean intercropping system was found to be the best from the view point of equivalent yield and economics.