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Thesis

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2022 - 20234
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Subject: Biochemistry × Start date: 2022 × Type: Thesis × Thesis Type: Ph.D ×
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Now showing 1 - 4 of 4
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    ThesisItemEmbargo
    Evaluation of Momordica spp. for bioactive components and antidiabetic potential
    (Punjab Agricultural University, 2022) Singla, Diksha; Sangha, Manjeet Kaur
    The present study evaluated antidiabetic potential of bioactive components from immature fruits (60 genotypes) of Momordica spp. in streptozotocin-induced diabetic Wistar rats. The fruit and its parts; epicarp, mesocarp, endocarp, and seeds were evaluated for biochemicals. PAUBG-407 possessed higher phenolics, fiber components, carotenoids, saponins, macro and microminerals; PAUBG-195 (alkaloids); PAUBG-130 (ascorbic acid and tocopherols); PAUBG-218 (proteins) and Punjab-15 (most bioactives). Whole fruit was rich in many bioactives. Charantin, soluble dietary fiber and momordicin-II were purified from whole fruits of PAUBG-407 while vicine and momordicin-I were purified from whole fruit of PAUBG- 195 and PAUBG-89, respectively and characterized on NMR and FT-IR. Their antidiabetic potential was evaluated in 7-8 week old rats, orally administered bioactives @100mg/kg b.w, daily for 4 weeks. Nine groups were made; normal (), untreated diabetic (II), diabetic + (metformin (I), charantin (IV), SDF (V), vicine (VI), momordicin-I (VII), momordicin-II (V), and diabetic+ all bioactives mixed in equal ratio (IX)). Their effect was assessed weekly and at 4 weeks (some parameters). Fasting and random blood glucose; kidney and Iiver CAT, SOD, GPx, GST, GSH. and TBARS: KFT (urea, creatinine, uric acid, Na', K and Ca); LFT (bilirubin. direct and indirect bilirubin, SGOT, SGPT, ALP, total protein, albumin and globulin): plasma insulin, Hb and HbAl c; serum lipid profile (TC, TG, VLDL, DL and LDL), hepatic enzymes- hexokinase, glucose-6-phosphatase and fructose-6- phosphatase; histological aberrations observed in liver, kidney, pancreas and brain improved SIgnificantly (p<0.0001) in diabetic rats treated with all bioactives but highly with momordicin-II and bjoactive mixture. PAUBG-407 may be used in improvement programmes generating antidiabetic karela. Future plans may envisage in testing antidiabetic potential of f targeted bioactives or use of targeted advanced line in diabetic human subjects.
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    Malt quality and thermostability studies in mutants, hulled, hull-less and wild genotypes of barley (Hordeum vulgare L.)
    (Punjab Agricultural University, 2023) Heena Rani; Bhardwaj, Rachana D
    Despite various attempts to develop malt hydrolytic enzymes, the catalytic activity and thermostability of these enzymes are still far from sufficiency for their use in the malting process. The present study explored diverse barley germplasm to identify the genotypes with high activity and thermostability of enzymes alongwith the proteins responsible for high malt yield. Based on enzymatic assays, we selected BL1714T, DWRB137T and BL2105T with highly activity and thermostability of α and β amylases and limit dextrinase, which are key diastatic power enzymes. The barley proteome of these genotypes was analyzed before and after kilning using label-free quantitative global proteomic approach against the control genotypes; BL1718Ctrl, DWRUB64Ctrl and BL2083Ctrl, respectively. Among various isoforms of hydrolytic enzymes Bamy 1 and Amy1_2 were more abundant in thermostable genotypes indicating their role in controlling the activity of these enzymes at high temperatures. Gene ontology enrichment analysis indicated disulfide reductase, exopeptidase, serine-type peptidase (serpin), cell wall hydrolase and oxidoreductase activities as most common enriched terms in thermostable genotypes. These proteins work to release the bound form of hydrolytic enzymes, resulting in their increased overall activity. These proteins could be employed as biochemical indicators for identifying barley lines with high activity and thermostability. Using GC-MS/MS, we identified maltose, glucose, talose, sucrose, fructose, turanose and other minor sugars in green and kilned malt. Talose and turanose were identified among major sugars for the first time during malting. Further, malt quality analysis suggested that βglucanase and malt β-glucan can be used as additional traits to produce malt with superior quality.
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    Defense response and source-sink relationship for imazethapyr tolerance in lentil (Lens culinaris L.).
    (Punjab Agricultural University, Ludhiana, 2023) Shivani; Grewal, Satvir Kaur
    Plant growth and yield reduction in lentil crop due to weed infestation is due to poor weed-crop competition. Imazethapyr (IM), controls wide spectrum of weeds as a selective herbicide that targets acetolactate synthase (ALS) which catalyzes the first reaction in biosynthesis of branched chain amino acids (BCAAs), required for plant growth and development. The present investigation was conducted to understand the effect of IM treatment and weed interference on defence mechanism, source-sink relationship and ALS activity along with morpho-physiological traits in IM-tolerant (LL1397 and LL1612) and susceptible (FLIP2004-7L and PL07) lentil genotypes. Lentil genotypes were grown under control (weed free), weedy check (weeds were growing with crop) and sprayed with imazethapyr at 50 days after sowing (DAS). Lower accumulation of methylglyoxal (MG) is due to higher activities of glyoxalase I, II & III enzymes, methylglyoxal reductase (MGR) and lactate dehydrogenase (LDH) in LL1397 and LL1612 after IM treatment as compared to FLIP2004-7L and PL07 along with higher glutathione (GSH) content due to increased γ-Glutamylcysteine synthetase (γ-GCS) help in their recovery post herbicide treatment. Imazethapyr treatment decreased chlorophyll and carotenoid content, plant height and number of pods under IM treatment in FLIP2004-7L and PL07, which resulted in decreased seed yield. Higher activities of ALS, threonine deaminase (TD) with or without any effector molecules and leucine dehydrogenase (LeuDH) was observed in LL1397 and LL1612 for maintaining BCAA pools as compared to FLIP2004-7L and PL07. Expression analysis of ALS gene depicted that 4 days after spray is a critical stage to show its effectiveness at which LL1397 and LL1612 showed higher expression while in PL07 and FLIP2004-7L, expression was highly reduced. Lower H2O2, MDA and DHA content, higher activities of antioxidant and proline metabolizing enzyme activities along with higher ascorbate and proline contents in tolerant (LL1397 and LL1612) might be protecting from herbicide induced oxidative damage thereby improving crop yield. Significantly higher activities of carbon metabolism enzymes in leaves, podwalls and seeds at different developmental stages in tolerant genotypes under herbicide stress as compared to susceptible lentil genotypes might be responsible for maintaining source-sink relationship required for proper growth, grain filling and seed setting. Similarly, enzymes of nitrogen metabolism also showed higher activities in all tissues of tolerant genotypes required for proper nitrogen uptake and better assimilation of inorganic nitrogen into organic nitrogen. Tolerant genotypes had higher total phenolic acid content after imazethapyr treatment as compared to susceptible genotypes with higher content of catechin hydrate, p-coumaric acid, caffeic acid, vanillic acid and rutin that might be contributing towards their better tolerance ability. Soluble protein content was decreased in all tissues of susceptible genotypes as IM treatment affected the protein turnover by accumulating free amino acids. This comprehensive knowledge of mechanisms underlying these metabolic changes after herbicide treatment might provide an efficient way of crop improvement by developing IM-tolerant genotypes.
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    ThesisItemOpen Access
    Biochemical studies on methionine accumulation in maize grains
    (Punjab Agricultural University, Ludhiana, 2022) Veena Devi; Chaudhary, Dharam Paul
    Present study was designed to understand the accumulation pattern of essential amino acids (methionine, lysine and tryptophan), methionine synthesis associated key enzymes activities and responsible genes expression in maize grains. For this purpose diverse panel of 300 inbred lines, procured from ICAR-IIMR and CIMMYT were screened for methionine content and a set of 22 experimental lines (12 high methionine and 10 low methionine) was selected for further study. Field parameters viz., Plant height, cob height, stem and root logging, no. of cobs, no. of rows/cob, no. of seeds/row, germination rate, anthesis and silking intervals, 100 kernel weight, specific gravity, moisture content were recorded. None of the field parameter showed any positive significant correlation with methionine content. The lines E7-24-3, E711-1, E19-14-1, E4-5-2, E2-52-1, E2-7 and E19-22-2 showed better field performance whereas the lines 174705 (3.293%) and 194010 (2.275%) showed highest methionine content thus can be used as acceptor and donors in breeding high methionine maize, respectively. Kernel colour showed correlation with methionine content. Lysine and tryptophan showed declining trend during kernel development and their accumulation was higher in low methionine lines. Aspartate kinase showed similar activity in both high and low methionine lines whereas cystathionine-gamma-synthase does not showed any fixed trend. Serine acetyltransferase enzyme activity was observed to be higher in high methionine than low methionine lines. Higher activity in high methionione lines indicated higher rate of cysteine synthesis, and its flow towards the synthesis of methionine. Its activity showed significant correlation (r = 0.87) with methionine content at 45th DAP. During kernel development zein (prolamin and prolamin-like) accumulated at higher rate in comparison to non-zeins (albumin, globulin and glutelins) in total protein. Methionine showed significant positive correlation with prolamins (r = 0.65) and proteins (r = 0.47). In SDS-PAGE 10-kDa δ-zein was more prominent in high methionine lines, whereas other zeins did not showed any change in high and low methionine lines. Lastly, the mRNA was quantified to study the expression profile of genes responsible for methionine accumulation. It was observed that 10-kDa δ-zein showed enhanced expression in high methionine lines, so its expression affects the accumulation of methionine in developing maize kernel.