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2010 - 20182
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Author: Arya Aravind × Start date: 2000 ×
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    ThesisItemOpen Access
    Development of functional est-ssr and analysis of genetic diversity in centella asiatica
    (Department of Plant Biotechnology, College of Agriculture, Vellayani, 2018) Arya Aravind; KAU; Sabu, K K
    Centella asiatica is a small trailing perennial herb and is the only species of Centella seen in India. Stem is green to greenish red colour and rooting at nodes. These connects plants each other. Petiole is long, smooth, green in colour. Leaves are palmately veined fleshy leaves. Plants are mainly found in marshy land of tropical and subtropical regions. Genetic diversity is that the total variety of genetic characteristics within the genetic makeup of a species. It plays a very important role within the survival and flexibility of a species and is important for a species to evolve. We aim to develop and use transcriptome based SSR molecular marker for analysis of genetic diversity in Centella asiatica in relation to the content of triterpenoids. To achieve that 129 Primers were designed from the transcriptome sequence obtained from NCBI. To validate the designed primers 15 primers were selected and used for genetic diversity analysis in 30 different Centella accessions collected from different regions of Tamil Nadu and Kerala. The genetic diversity analysis result grouped the accessions in to six group based on the genetic distance. Single accessions was randomly selected from each group to chemical analysis the asiaticoside content and additionally two phenotypic characters were also characterised in all 30 collected accessions. The result of genetic diversity analysis shows the less Nei heterozygosity (0.0433) between the studied accessions and the positive correlation (0.142) with the asiaticoside content. From the analysed phenotypic characters, number of leaves per node character shows the interesting positive correlation (0.291) with asiaticoside content than genetic diversity. This study gives the positive and initiative step to the genetic diversity and the asiaticoside content correlations. This will be helpful to find out the functional marker related to asiaticoside content which will be useful in MAS studies in future.
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    ThesisItemOpen Access
    Studies on sequential post-mortem changes of isolated chicken eye
    (Centre for Excellence in Pathology, College of Veterinary and Animal Sciences, Mannuthy, 2010) Arya Aravind; KAU; Vijayan, N
    The present investigation was undertaken to study the sequential postmortem changes of different components of chicken eye and to choose an ideal fixative. Six eyes each were fixed at zero hour, half hour, one hour, one and a half hours, two hours, four hours and twelve hours in ten per cent neutral buffered formalin and gluteraldehyde fixative. Eyes were fixed for a minimum of three weeks. A clean cut was made near to the midline of the fixed eye slightly to one side of it, so that the origin of the optic nerve and pupil were included in the sections. The eye consisted of three tunics; tunica fibrosa consisting of cornea and sclera, tunica vasculosa with choroid, ciliary body and iris and tunica interna consisted of retina. The postmortem changes were mostly appreciated in the cornea, which included condensation of the nucleus of the epithelium of cornea, interepithelial detachment and exfoliation of epithelium. The cytoplasm revealed vacuolar and degenerative changes and there was separation of collagen fibres of corneal stroma. The corneal endothelium showed swelling, lysis and detachment. The presence of lysed erythrocytes was prominent after two hours in the choroid. As the time interval advanced, there were varying degrees of dispersion of melanin pigment. The swelling of the cytoplasm of the ciliary body was more evident in the non- pigmented epithelial layer. The epithelium of the iris showed detachment and fragmentation. Retinal detachment was noticed from zero hour of fixation in GF fixative and ten per cent NBF fixative. The changes were prominent in the ganglion cells which showed condensation of the nuclei along with vacuolar and lytic changes of the cytoplasm. Postmortem changes of pecten were appreciated by the lysed erythrocytes in the capillaries along with the vacuolar degeneration and lytic changes affecting melanocytes and hyalocytes. PAS positive areas were detected in the Descemet’s membrane and Bowman’s membrane of cornea, lens capsule, pecten and layer of rods and cones of retina. Masson’s trichrome staining proved to be useful to appreciate the changes in the collagen fibres, muscles and epithelium. The histometry of the eyeball showed a significant decrease in thickness of cornea at 120 minutes when compared with zero hour in neutral buffered formalin fixative. From the study it can be concluded that GF fixative is a better fixative for eye than 10 per cent NBF fixative.