Browsing by Author "Kannangara, S.D."

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Assessing Nephrotoxic Heavy Metal Contamination in Reservoir Sediments: Implications for Human Health and Aquatic Ecosystems
(Gampaha Wickramarachchi University of Indigenous Medicine, 2024) Dayananda, M.D.N.R.; Liyanage, J.A.; Kannangara, S.D.
Background: Wetlands, often referred to as the "kidneys of the earth," play a crucial role in ecosystem services. This study focuses on reservoirs in dry zone, in Sri Lanka, recognizing their significance in fulfilling diverse ecological needs. Originality/Value: The research addresses the scarcity of studies linking Chronic Kidney Disease of unknown etiology (CKDu) hotspots with heavy metal contamination in reservoir sediments. Objective: The study aims to assess nephrotoxic heavy metal contaminations in reservoir sediments, specifically focusing on the potential health risks for humans through the ecological implications for aquatic ecosystems. Methodology: Ten (10) triplicated composite sediment samples were randomly collected from Ulhitiya, Diwulankadawala, Wahalkada, (within the CKDu hotspots), and Namaloya (the Reference) reservoirs. Inductively Coupled Plasma Mass Spectrometry was employed to determine metal concentrations followed by microwave digestion. Inverse Distance Weighted (IDW) tool in ArcMap. 10.8 Software was used for the spatial interpolations. Findings: Ulhitiya, Diwulankadawala, and Wahalkada reservoirs exhibited elevated contents of Cd, Pb, As, Cr, Cu, and Zn in sediments than the reference. Sediment-bound As, Cu, Zn, and Cd were higher than NOOA-ERL and ERM levels and instead of Pb, all the other selected heavy metals exceeded the LELs, implicating harmful biological impacts on living organisms inhabiting the selected reservoirs in the CKDu hotspots. A clustering pattern in higher concentrations of Cd and Pb was observed near the water inputs of the reservoirs in CKDu endemic areas. Conclusions: Heavy metal contamination in reservoir sediments, particularly Cd and Pb, poses risks to aquatic ecosystems and human health through the food chain, especially in CKDu hotspots.
Fungi vs. Fungi in Biocontrol: An Overview of Fungal Antagonists Applied Against Fungal Plant Pathogens
(Front. Cell. Infect. Microbiology, 2020) Thambugala, K.M.; Daranagama, D.A.; Phillips, A.J.L.; Kannangara, S.D.; Promputtha, I.
Plant pathogens cause severe losses or damage to crops worldwide and thereby significantly reduce the quality and quantity of agricultural commodities. World tendencies are shifting towards reducing the usage of chemically synthesized pesticides, while various biocontrol methods, strategies and approaches are being used in plant disease management. Fungal antagonists play a significant role in controlling plant pathogens and diseases and they are used as Biocontrol Agents (BCAs) throughout the world. This review provides a comprehensive list of fungal BCAs used against fungal plant pathogens according to modern taxonomic concepts, and clarifies their phylogenetic relationships because thewrong names are frequently used in the literature of biocontrol. Details of approximately 300 fungal antagonists belonging to 13 classes and 113 genera are listed together with the target pathogens and corresponding plant diseases. Trichoderma is identified as the genus with greatest potential comprising 25 biocontrol agents that have been used against a number of plant fungal diseases. In addition to Trichoderma, nine genera are recognized as significant comprising five or more known antagonistic species, namely, Alternaria, Aspergillus, Candida, Fusarium, Penicillium, Pichia, Pythium, Talaromyces, and Verticillium. A phylogenetic analysis based on partial sequences of the 28S nrRNA gene (LSU) of fungal antagonists was performed to establish their phylogenetic relationships.