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Subject: Biochemistry × End date: 2006 × Start date: 2006 × Type: Thesis × Thesis Type: M.Sc ×
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Now showing 1 - 6 of 6
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    ThesisItemOpen Access
    Biochemical studies on moth bean [Vigna aconitifolia (Jacq.) marechal] in relation to yellow mosaic virus
    (CCSHAU, 2006) Arora, Ruby; Joshi, U.N.
    The present investigation was conducted to study the biochemical changes induced by yellow mosaic virus in resistant (HMO 61 and RMO 225) and susceptible (GMO 9703 and GMO 9704) genotypes of mothbean. Activities of enzymes viz. peroxidase, polyphenol oxidase, phenylalanine ammonia lyase, tyrosine ammonia lyase were increased, whereas the catalase activity was found to decrease in the leaves of inoculated plants of all the four genotypes as compared to the uninoculated plants. Peroxidase activity increased markedly in the susceptible genotypes over the resistant genotypes of inoculated plants. The activities of polyphenol oxidase showed increasing trend in the inoculated leaves of resistant genotypes as compared to the resistant genotypes of uninoculated ones. In the inoculated plants, the phenolic compounds viz. total phenols, flavanols and ortho-dihydric phenols were found to be higher in the resistant genotypes of inoculated plants. Among the structural carbohydrates, no regular trend was observed in NDF and silica content while the contents of ADF, cellulose and lignin increased significantly in the plants inoculated with YMV. The hemicellulose content was found to decrease after inoculation with the pathogen. SDS-PAGE indicates that polypeptides of molecular weight 64.27 KD in seed, and 63.10, 100 and 89.13 KD at vegetative, flowering and grain filling stage in leaves might play a definite role in defense mechanism against YMV in mothbean. The results indicate that the differences between tolerance and susceptibility of host are quantitative as well as qualitative so defense against a pathogen entails major changes in the biochemical components of the plant. A probable biochemical mechanism for defense against YMV in mothbean was suggested.
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    ThesisItemOpen Access
    active oxygen scavenging system as influenced by NaCl salinization in cotton (gossypium hirsutum)
    (CCSHAU, 2006) Nisha Kumari; Talwar, Gurmeet
    The present investigation was carried out to investigate the effect of NaCl salinization on plant water status, cell membrane damage, chemical constituents, antioxidative enzymes and metabolites in salt-sensitive (H-1236) and salt-tolerant (H-1226) genotypes of cotton seedlings. LD-50 (lethal dose) level of NaCl was 125 mM. Screening of twenty genotypes were done at 125 mM of NaCl for their NaCl-tolerance. The relative water content and osmotic potential declined significantly with induction of salt stress, though effect was more in sensitive (H-1236). Salt stress increased the content of chemical constituents like carotenoids in both genotypes. There was enhancement in the activities of antioxidant enzymes, however, glutathione reductase showed more increase in salt tolerant genotype. The higher accumulation of H2O2 and malondialdehyde was observed with induction of salt-stress in both the genotypes, but it was more in salt-sensitive genotype as compared to the salt-tolerant. The results presented exhibited that tolerance to salt stress was more in H-1226 (tolerant) as compared to H-1236 (sensitive).
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    ThesisItemOpen Access
    Grain quality of grey and yellow pearl millet [Pennisetum glaucum (L.) R. Br.]
    (CCSHAU, 2006) Praduman; Chugh, L.K.
    The investigations were carried out on pearl millet (Pennisetum glaucum (L.) R. Br.). Twelve genotypes six each of yellow (ICMA 94222 x 78/711, ICMA 94222 x 96-AC-82, ICMV 155 (yellow), ICMV 221 (Yellow), HMS 36B and ICMB 94222) and grey (HTP 94/54, 78/711, HHB 94, HHB 197, Barmer Pop and ICMV 221 (grey) genotypes were subjected to chemical/biochemical analysis. Sugars (total soluble sugar, reducing and non-reducing), amylose and crude fibre of either grey or yellow pearl millet genotypes did not vary significantly. Starch content of yellow and grey pearl millet genotypes ranged from 62.1 to 69.4 (HTP 94/54). Average crude protein content of yellow genotypes (12%) was higher than that of grey genotypes (9.8%), but mean fat content (6.09%) of grey genotypes was higher than that of yellow genotypes (15.2%). Content of total phenols and C-glycosylflavones in yellow as well as grey genotypes varied significantly (50.3 to 88.1 mg/100 g). Except magnesium and manganese mineral profile of the yellow genotypes, compared to that of the grey genotypes, was statistically either equal or better. Total carotenoids of grey genotypes (2.91 ppm) was higher than that of yellow genotypes (2.32 ppm). -carotene content was not detected in any of the genotypes studied. Amylase activity ranged from 5.5 to 32.92 units among the yellow and grey genotypes. To look for any possible correlation between C-glycosylflavones content with development of off odour, flour of all genotypes was stored for a period of 4 or 8 days at 37oC and at ambient RH. Fat acidity of all the genotypes was drastically increased (1.7 to 6.8 fold) by eighth day of storage of their flour. Average free fatty acid and aid value of the grey genotypes was comparatively higher than that of the yellow genotypes after 4 and 8 days of storage of their flour. The rate of increase in peroxide value of oil extracted from flour of the genotypes in each category varied widely. The enzyme activity of grey genotypes was marginally higher than that of the yellow genotypes. Magnitude of off odour detected after 8 days of storage did not correspond either to fat content, absolute values of fat acidity, free fatty acids and peroxide value or to rate of increase in their values between 0 and 8 days of storage but matched with level of peroxidase activity and more closely with C-glycosylflavones content of grains of the genotypes irrespective of their colour. It was concluded that development of off odour might be related to peroxidase activity as well as phenolics particularly C-glycosylflavones content.
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    ThesisItemOpen Access
    Studies on the development of rancidity in stored flour of pearl millet [Pennisetum glaucum (L.) R. Br.]
    (CCSHAU, 2006) Sharma, Amit; Saharan, M.R.
    The investigation was carried out on two pearl millet hybrids viz., HHB 94 and ICMA 94222A x 78/711. The former is grey in colour and has high fat and phenols content and possesses high activity of peroxidase. Light yellow hybrid ICMA 94222A x 78/711 also has high fat content and possesses comparatively low total phenols content as well as low activity of peroxidase. Composition of flour of both hybrids was modified by differential extraction of fat and phenols. Type I and type II flour containing 40 and 60% lesser fat content (compared to control flour) whereas type III and type IV flour containing 40 and 60% lesser phenols respectively were prepared. The unmodified or modified flour was stored at 37oC at ambient relative humidity for 0, 4 or 8 days in a BOD incubator. Defatting of flour caused an increase in fat acidity ‘FA’ and free fatty acids ‘FFAs’ but showed no effect on peroxide value ‘PV’ of the flour. On the other hand, extraction of phenols decreased FA, FFAs and PV of flour of both hybrids. Values of rancidity indicators viz., FA, FFAs and PV of control as well as modified flour (all the types) of both hybrids increased with increasing storage time. FA and FFAs in flour of both the hybrids having lesser phenol content increased much faster than that had correspondingly lesser fat content. Despite a higher rate of increase, by 8th day of storage, FA and FFAs of type II and type IV flour was much less than that of type I and type II flour. There was no effect of reducing fat content of fresh flour of either of the hybrids on content of total phenols and on level of peroxidase activity. On the other hand, extraction of phenolics showed a profound inactivating effect on the enzyme activity of both the hybrids. In control flour of HHB 94 and ICMA 94222 x 78/711, very strong and strong rancid odour was detected on 8th day of storage. Removal of phenolics from flour of both the hybrids before storage reduced the intensity of off-odour developed during storage of flour. Blanching treatment was very effective for inactivating peroxidase in grains. Blanching of grains of HHB 94 for 120 seconds almost completely inactivated peroxidase. FA, FFAs and PV of fresh flour produced from grains blanched for 90 and 120 seconds was lower than that produced from untreated grains. Upon storage, FA, FFAs and PV of control flour increased with increasing time of storage whereas in flour produced from grains blanched for 120 seconds the values of these rancidity indicators virtually did not change further. Flour produced from blanched grains (type V, type VI and type VII) had lesser total phenols content than that of control flour. There was no change in the content of total phenols of lour prepared from untreated as well as treated grains upon storage. Based on results of both the experiments, it was concluded that high content of total phenols and high activity of peroxidase are responsible for generating rancid odour in stored flour rather fat content of grains.
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    ThesisItemOpen Access
    Response of reactive oxygen species production and antioxidant metabolism to putrescine under water stress in wheat leaves
    (CCSHAU, 2006) Bhankar, Vinita; Sawhney, Veena
    The reduction in RWC and osmotic potential by water deficit stress in the seedlings of WH147 and UP2338 cultivars of wheat was partially enhanced by putrescine applicaton. The superoxide radicals and H2O2 production was high in water deficit plants, also it resulted in the increased lipid peroxidation, but they were decreased on addition of putrescine to the stressed plants, indicating the repair of cellular membranes. Water deficit stress enhanced the activities of H2O2 scavenging enzymes viz. catalase, ascorbate peroxidase and enzymes of ascorbate-glutathione cycle but activity of superoxide dismutase, a H2O2 producing enzyme, was decreased under stress. Exogenously applied putrescine further elevated the activities of these enzymes along with that of superoxide dismutase in both the cultivars. The level of total and reduced glutatione which was decreased due to water stress was recovered by putrescine application. Redox state of glutathione and ascorbate, disturbed in the stressed plants, was found to recover in putrescine treated stressed plants.
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    ThesisItemOpen Access
    Studies on the development of rancidity in stored flour of pearl millet [Pennisetum glaucum (L.) R. Br.]
    (CCSHAU, 2006) Sharma, Amit; Saharan, M.R.
    The investigation was carried out on two pearl millet hybrids viz., HHB 94 and ICMA 94222A x 78/711. The former is grey in colour and has high fat and phenols content and possesses high activity of peroxidase. Light yellow hybrid ICMA 94222A x 78/711 also has high fat content and possesses comparatively low total phenols content as well as low activity of peroxidase. Composition of flour of both hybrids was modified by differential extraction of fat and phenols. Type I and type II flour containing 40 and 60% lesser fat content (compared to control flour) whereas type III and type IV flour containing 40 and 60% lesser phenols respectively were prepared. The unmodified or modified flour was stored at 37oC at ambient relative humidity for 0, 4 or 8 days in a BOD incubator. Defatting of flour caused an increase in fat acidity ‘FA’ and free fatty acids ‘FFAs’ but showed no effect on peroxide value ‘PV’ of the flour. On the other hand, extraction of phenols decreased FA, FFAs and PV of flour of both hybrids. Values of rancidity indicators viz., FA, FFAs and PV of control as well as modified flour (all the types) of both hybrids increased with increasing storage time. FA and FFAs in flour of both the hybrids having lesser phenol content increased much faster than that had correspondingly lesser fat content. Despite a higher rate of increase, by 8th day of storage, FA and FFAs of type II and type IV flour was much less than that of type I and type II flour. There was no effect of reducing fat content of fresh flour of either of the hybrids on content of total phenols and on level of peroxidase activity. On the other hand, extraction of phenolics showed a profound inactivating effect on the enzyme activity of both the hybrids. In control flour of HHB 94 and ICMA 94222 x 78/711, very strong and strong rancid odour was detected on 8th day of storage. Removal of phenolics from flour of both the hybrids before storage reduced the intensity of off-odour developed during storage of flour. Blanching treatment was very effective for inactivating peroxidase in grains. Blanching of grains of HHB 94 for 120 seconds almost completely inactivated peroxidase. FA, FFAs and PV of fresh flour produced from grains blanched for 90 and 120 seconds was lower than that produced from untreated grains. Upon storage, FA, FFAs and PV of control flour increased with increasing time of storage whereas in flour produced from grains blanched for 120 seconds the values of these rancidity indicators virtually did not change further. Flour produced from blanched grains (type V, type VI and type VII) had lesser total phenols content than that of control flour. There was no change in the content of total phenols of lour prepared from untreated as well as treated grains upon storage. Based on results of both the experiments, it was concluded that high content of total phenols and high activity of peroxidase are responsible for generating rancid odour in stored flour rather fat content of grains.