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20183
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Subject: Biochemistry × End date: 2018 × Start date: 2018 × Type: Thesis × Thesis Type: M.Sc ×
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    ThesisItemOpen Access
    Studies on biochemical basis for cotton leaf curl disease tolerance in Gossypium hirsutum L.
    (CCSHAU, 2018) Taranjeet Kaur; Mandhania, Shiwani
    Viruses have profound effect on the growth and productivity of plants. With reference to the cotton crop, CLCuD caused by CLCuBuV has been recognized as a serious threat to cotton production in Indian subcontinent. Information on cotton and CLCuV interaction is still not convincingly explained. In the present study, the constituents like RWC, electrolyte leakage, total chlorophyll content, MDA content, total soluble protein, total sugar content, total phenolics, H2O2, gossypol content and the activities of defense related proteins viz. POX, PPO, CAT and PAL were scrutinized at different stages of infestation in GCH 3, HS 6 genotypes of cotton and in additional genotype (HD 432) to look over the biochemical basis for CLCuD tolerance mechanism. It was found that the maximum RWC, total chlorophyll content and total soluble protein was present in highly tolerant and resistant genotype respectively at 0 DAI. Decline in the amount of these constituents reported in all genotypes but maximum loss took place in HS 6. Least amount of electrolyte leakage, H2O2 and MDA content was present in HD 432 at all stages of infestation. Significant increase in these parameters observed in HS 6 post incursion of virus. Maximum total sugar content was present in HS 6 at 0 DAI, ebb was more in GCH 3 due to infestation. As a consequence of viral infection, the level of total phenolic compounds and gossypol content increased significantly in all genotypes while maximum increase was in GCH 3. With the progression of infestation period significant increase was reported in the activities of PAL, PPO, POX and CAT in all genotypes. Thus, the increase in the level of total phenolic compounds, gossypol with increase in the activities of all studied enzymes can be correlated with the potency of the plant to strive against CLCuD.
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    ThesisItemOpen Access
    Extraction and evaluation of antioxidant capacity of total phenolics from lychee (Litchi chinensis L.) seeds
    (CCSHAU, 2018) Nagesh C.R.; Ajay Pal
    Lychee seed, being a biowaste, is an inexpensive source of a variety of polyphenols. However, extraction yield/efficiency of total phenolics from lychee seed powder (LSP) depends on extraction conditions. Hence, in present study, optimum conditions for extraction of phenolics from LSP were deduced using one-factor-at-a-time approach followed by response surface methodology (RSM). The factorial, axial and center point experiments of central composite rotatable design (CCRD) of RSM were carried out to investigate the linear, quadratic and interactive effects of three independent variables namely volume of extractant (ml/g), agitation rate (rpm) and extraction time (min) on the yield of phenolics. Regression analysis showed that ~92% of the variation could be explained by the model. Software mediated numerical optimization was done with the constraint of minimum volume of extractant and extraction time separately for maximum yield of TPC. The experimental values were in accordance with the predicted values, indicating the adequacy of model and success of RSM in optimizing the extraction conditions. Lychee seed extract (LSE) was analyzed for profiling of phenols and fatty acids using H-UPLC and GC, respectively. Despite reported phenolic compounds, we found new phenolics namely apigenin, catechol, catechin, chlorogenic acid, diadzein, salicyclic acid, trans-ferulic acid, trans-sinapic acid and vanillin in LSE. Among six different fatty acids identified, oleic acid and linoleic acid were abundant. Further, LSE was assayed for its antioxidant activities using an array of tests including free radical scavenging activity, nitric oxide scavenging activity (NOSA), hydroxyl radical scavenging activity, metal chelation activity, total antioxidant activity (TAA), total reducing power (TRP), lipid peroxidation inhibition activity (LPIA) and protein oxidation inhibition activity. Prokaryotic and eukaryotic DNA damage protective efficacy of LSE was also observed using pBR322 plasmid and human lymphocytes, respectively. Results of various experiments showed substantial antioxidant activity of LSE and advocate its exploitation as a source of natural antioxidants to counter ROS-induced pathologies or diseases.
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    ThesisItemOpen Access
    Physico-chemical and kinetic properties of fatty acid esterase from pearl millet [Pennisetum glaucum (L.) R. Br.] hybrid HHB 197 and its parents
    (CCSHAU, 2018) Sheenu; Chugh, L.K.
    Fatty acid esterase (FAE) (E.C. 3.2.2.1) was partially purified from flour of pearl millet hybrid HHB 197 and its parents viz., A-line ICMA 97111 and R-line HBL 11 by ammonium sulphate fractionation (30-60 % saturation) followed by gel filtration through Sephadex G-75. FAEs of A-line ICMA 97111 and R-line HBL 11 eluted as a single peak were designated as FAE I and the enzyme resolved into two distinct peaks from the hybrid HHB 197 were designated as FAE I and FAE II. After gel filtration 15 to 55 % of the enzyme was recovered with specific activity of 7.35 to 12.85 units/mg proteins with fold purification ranging from 2.8 to 5.5. Physico-chemical and kinetic properties of the enzyme of these genotypes were compared. The FAE I of the hybrid HHB 197, A-line ICMA 97111 and R-line HBL 11 had identical molecular weight of about 67.6 kDa. Molecular weight of FAE II of the hybrid was 22.3 kDa. Both FAE I and FAE II of the hybrid showed optimum temperature of 40oC. FAE I of A-line ICMA 97111 and R-line HBL 11 had optimum temperature of 40-45 and 45oC, respectively. FAE I of ICMA 97111 lost maximum activity when incubated for 20 min at 50 OC. At this temperature FAE I of the hybrid was comparatively more stable. Except FAE II of HHB 197, FAE I of all the genotypes showed optimum activity at pH 8. Ascorbic acid, EDTA and SDS were found to be inhibitory for all the FAEs. Fe3+, Cu2+ and Zn2+ showed significant deleterious effect on the activity of FAEs of all the genotypes. Co2+ was stimulatory for FAE II of hybrid HHB 197 and FAE I of R-line HBL 11 and had slight deleterious effect on FAE I of the hybrid and A-line ICMA 97111. All FAEs showed typical hyperbolic response to concentrations of the substrate para-nitrophenylbutyrate (pNPB). Km values were calculated using the software GraphPad Prism ver. 7. Km value of FAE I of R-line HBL 11 (0.540 M p-NPB) was the highest followed by those of FAE I (0.155 M p-NPB) and FAE II (0.100 M p-NPB) of the hybrid and that (0.067 M p-NPB) of A-line ICMA 97111. High Km value of FAE I of the R-line HBL might be partly responsible for slow in situ lipids hydrolysis.