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U n i v e r s i t y of P e r a d e n i y a

The Institutional Repository of the University of Peradeniya is the University's digital gateway to scholarly knowledge and research excellence. Established as the next phase of the Digital Library initiative launched by the University Library in 2011, it preserves, showcases, and provides open access to the intellectual output of the University community.

Through a rich collection of research articles, conference proceedings, theses, dissertations, and other scholarly works, the repository enhances the visibility, accessibility, and long-term preservation of knowledge, extending the global reach and impact of the University of Peradeniya’s academic and research contributions.

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Chronic Kidney Disease in animals: a study on kidney and liver pathology of cattle from CKDu-prevalent North Central Province of Sri Lanka
(University of Peradeniya, Sri Lanka, 2021-11-11) Rodrigo, S.A.C.H.; Palkumbura, P.G.A.S.; Jayaweera, W.; Wijesundera, R.R.M.K.K.
Chronic Kidney Disease of unknown aetiology (CKDu) is a major health issue in Sri Lanka. Several studies have identified renal histopathologies in humans with CKDu. To the authors‘ knowledge, there are no reports of pathology of animal tissues in CKDu- prevalent areas globally or locally to date. This study investigates whether similar lesions prevail in animals and establishes the gross and histopathological morphology of renal and hepatic tissues of cattle from CKDu-endemic North Central Province (NCP). Forty (n=40) kidney and liver samples of Jersey cattle from NCP were collected mainly from abattoirs. Control samples (n=40) were collected from Jersey cattle of non-CKDu- endemic Kandy area. Forty percent (40%) of kidney samples showed multifocal petechial haemorrhages as the sole gross pathological lesion. However, gross liver lesions were not observed. The most common histopathological lesion in the kidney was tubular degeneration; observed in all test samples (100%). Other conspicuous lesions were lymphocytic infiltration (80%), interstitial fibrosis (55%), and glomerulosclerosis (50%). Common hepatic lesions were lymphocytic infiltration (70%) along with centrilobular necrosis (70%). These lesions were moderate to severe in severity and multifocal to diffuse in distribution. Only 15% of control samples showed mild focal lymphocytic aggregates as the sole lesion in both renal and hepatic tissues. Current literature on human CKDu reports similar tubulointerstitial morphology in renal tissues; however hepatic lesions have not been investigated. The renal and hepatic lesions were comparatively extensive in test samples than in controls. Renal lesions of cattle showed high similarity with those of humans. Liver lesions could not be compared since hepatic histopathology of CKDu patients is still unknown. Our findings are probably indicative of the effects of environmental risk factors common to humans and animals in this area. Since age and clinical history of these animals are unknown, further studies should investigate the exact causes of these lesions.
Optimization of In vitro proliferation assay for haemonchus contortus antigen sensitized lymphocytes in goats
(University of Peradeniya, Sri Lanka, 2021-11-11) Mendis, W.RH.; Mahakapuge, T.A.N.; Wijewardana, V.; Rajapakse, R.P.V.J.
The cell-mediated immune responses generated in the host could be measured by using in vitro lymphocyte proliferation assay. Once the lymphocytes are sensitized in vivo for a specific antigen, in vitro antigenic stimulation causes exponential antigen specific lymphocyte proliferation. Haemonchus contortus, an abomasal blood sucking parasite, induces cell-mediated immune responses in goats. Current study was conducted to optimize the methodology of in vitro proliferation at different antigen concentrations and to evaluate the cell proliferation using flow cytometer. Blood was collected from four goats (Saanen breed, aged less than 6 months) that were infected with H. contortus. Peripheral Blood Mononuclear Cells (PBMC) were isolated using the standard Pancoll- hypaque technique. Cells were cultured in complete RPMI media (RPMI 1640 supplemented with 2.05 mM L-glutamine, 2 g/L sodium bicarbonate, penicillin (100 IU/mL) and streptomycin (100 μg/ml) and 10% FBS) for 3 days at 37°C with 5% CO₂. Well known lymphocyte mitogen, Concanavalin A was used as a positive control at 5, 10 and 20 μg/mL, and H. contortus L3 somatic larval antigen was used at 200, 100, 50, 25, 10, 8, 6, 4 and 2 μg/mL concentrations. Concanavalin A at 5 μg/mL and the somatic larval antigen at 25 μg/mL yielded maximum in vitro lymphocyte proliferation. The results confirmed the basic requirements essential for goat in vivo sensitized lymphocyte proliferation.
Variation of catechins and caffeine in a bi-parental progeny of tea [Camellia sinensis (L.) O. Kuntze]
(University of Peradeniya, Sri Lanka, 2021-11-11) Kottawa-Arachchi, J.D.; Ekanayake, G.; Ranatunga, M.A.B.; Amarakoon, A.M.T.; Gunasekare, M.T.K.; Sharma, R.K.; Attanayake, R.N.
Tea [Camellia sinensis (L.) O. Kuntze], the second most consumed beverage in the world, is a rich source of polyphenolic compounds. The characteristic properties of tea depend on the biochemical compounds present in tea leaf. Hybridization of tea aims at developing new cultivars with more favorable levels of biochemicals for commercial exploitation. Early screening of putative hybrid populations would facilitate selection of elite genotypes with desirable biochemical properties. Tea with naturally low caffeine content is highly demanded while, high catechin content ensure better quality. Current study estimated the catechins and caffeine contents in 126 hybrids generated by two diverse parental tea cultivars; TRI 2043 and TRI 3055 to screen hybrids with high catechin and low caffeine content. Three sets of finely ground freeze-dried fresh leaf samples of direct and reciprocal crosses were extracted with 70% methanol and used to determine Caffeine, (+)-catechin (C), (-)-epicatechin (EC), (-)-epicatechin gallate (ECg), (-)- epigallocatechin (EGC), (-)-epigallocatechin gallate (EGCg) and gallic acid using high performance liquid chromatography (HPLC) protocols. A significant variation was observed in these compounds. Among major catechins, EGCg was the highest (mean 70.28 ± 15.24 mg g-1 ) followed by ECg, EGC, EC and C. Genotypes no. 129 and 138 recorded highest total catechin content (192.80 mg g⁻¹ ) and lowest caffeine content (19.34 24 mg g⁻¹ ) respectively. Mid-parent heterosis for EGC was 18.43% and 11.01% in direct and reciprocal crosses respectively. Majority of the crosses exhibited positive better parent heterosis for EGC implying that they were superior to both parents TRI 2043 and TRI 3055. Mid-parent heterosis for caffeine was -7.09% and 7.19% in direct and reciprocal crosses respectively. Negative mid-parent heterosis for caffeine indicated the existence of genotypes in the population which can be utilized to develop low caffeine and high catechin tea cultivars.
Analysis of genomic data of pyricularia oryzae species causing rice blast
(University of Peradeniya, Sri Lanka, 2021-11-11) Samuel, A.C.; Nawarathna, L.S.; Ariyarathne, H.A.C.K.
Blast, caused by the fungus Pyricularia oryzae (P. oryzae), is the most destructive disease of rice prevalent globally. The rice quantity lost annually to this disease, which is over 30% of its annual production, could sustain approximately 60 million people. Fungicides and other means for disease control are ultimately futile due to the development of fungicidal resistance and adaptation among pathogen populations. Computational methods have been increasingly applied to design accurate and affordable biological experiments. This analysis identified regions of the genome that are discriminative for the selected fungus and hence can be used for pathogen diagnosis. Comparative analysis was performed with four other fungal pathogens that cause the most economically harmful rice diseases in Sri Lanka, namely; Rhizoctonia solani, Cochiobolus miyabeanus, Ustilaginoidia virens (U. virens) and Sarocladium oryzae (S. oryzae). This study used bioinformatics techniques such as pairwise alignments to enumerate mutations. The study was restricted to the 1ˢᵗ chromosome of the genome due to limited processing storage. Markov-models and the Needleman-Wunsch algorithm were employed extensively. Based on the Kruskal-Wallis test, there was no difference in the distributions of proportions of each of the four nucleotides within the genome of P. oryzae at 5% significance level. However, the regions from the 300,001bp to 400,000bp; 1,400,001bp to 1,500,000bp and 4,100,001bp to 4,200,000bp contained high proportions of adenine and thymine (AT rich) and low proportions of guanine and cytosine (GC poor) relative to the rest of the genomic divisions. Pairwise alignments between the 1ˢᵗ chromosome of P. oryzae and randomly selected regions of U. virens and S. oryzae, identified distinctive regions in P. oryzae from the 720,001bp to 730,000bp pointing to unique genomic sections in comparison to other rice pathogenic fungi. Further analysis of these P. oryzae genomic regions will enable developing molecular tools to distinguish and diagnose the pathogen.
Changes of selected phytochemical contents in tomato (Solanum Lycopersicum L.) fruits in response to postharvest hot water treatments
(University of Peradeniya, Sri Lanka, 2021-11-11) Zaina, M.N.F.; Dissanayake, P.K.
Tomato (Solanum lycopersicum L.) is one of the major fruits that contain high amount of lycopene, an important intermediate in the biosynthesis of many carotenoids including β- carotene. Lycopene shows the highest antioxidant activity among phytochemicals present in tomato fruit. Aims of this study were to evaluate the effect of hot water treatments (dipping in hot water bath) on phytochemical properties of tomato fruits and to find the relationship between heat and lycopene development in tomato fruits. pH (using pH meter), total soluble solids (brix value) content (using refractometer), vitamin C (by titrimetry), total polyphenolic content (TPC), and total flavonoid content (TFC), lycopene, total carotene (using spectrophotometer) were measured at three different colour development stages (Colour break, Orange, Red) of fruit after imposing to different hot water treatments (control, 40 ⁰C, 60 ⁰C, 80 ⁰C) for 10 minutes. Experiment was conducted in Complete Randomized Design with four replications. Upon hot water treatments pH and brix values of fruit increased in all three colour development stages. Lycopene and total carotene contents also increased with increasing temperature of hot water treatments and higher contents of those two components were observed in red colour stage than in other stages. The highest vitamin C content was observed in control treatment and it reduced gradually with increasing temperature. Highest TPC and TFC contents were recorded in the tomatoes which were subjected to hot water treatments than the control. However, a consistent relationship between the hot water treatment & TPC & TFC contents in different ripening stages of fruit could not be found. Overall results indicated that heat imposed by hot water differently affected phytochemicals in ripening tomato fruits while conserving some phytochemicals with increasing temperature such as lycopene.