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Item Screening of microcystin and microcystin-producing genes in Labugama and Kalatuwawa reservoirs in Sri Lanka(Research Symposium on Pure and Applied Sciences, 2018 Faculty of Science, University of Kelaniya, Sri Lanka, 2018) De Silva, I. U.; Manage, P. M.Microcystins (MCs) are the most widely studied carcinogenic cyanobacterial hepato- and neurotoxins. The MCs are synthesized by a non-ribosomal pathway through a multifunctional enzyme complex known as microcystin synthetase (mcy) encoded by the mcy gene clusters. The present study was aimed to screen MCs and MC-producing genes in Labugama and Kalatuwawa reservoirs which satisfies 60% of drinking water requirement for Colombo District. In the study, plankton and water samples were collected from the two reservoirs prior to water treatment process. The sampling was performed using a boat on the first week of each month from August to October in 2017 where three sampling locations were selected to collect water at each sampling time. Horizontal plankton samples were collected at 10 cm depth in each location using a 55 µm plankton net while the boat was moving. Water temperature and pH were measured on site using digital meters. Total inorganic nitrogen (N-NO3-, N-NO2-, N-NH3) and total phosphorous were determined using standard spectrophotometric methods, and cyanobacteria were identified under a light microscope using standard algae and cyanobacteria identification keys. Microcystis spp. were isolated and monocultures were prepared on cyanospecific BG 11 media from which the genomic DNA was extracted for the screening of MC-producing gene cluster in water samples using the Polymerase Chain Reaction (PCR). MCs were analysed by High Performance Liquid Chromatography (HPLC) and Enzyme Linked Immunosorbent Assay (ELISA) respectively. Temperature of water samples ranged between 27.8 and 28 oC while pH fluctuated in a range between 7.2 and 7.5. Total inorganic nitrogen was recorded from 0.02 to 0.03 mg/L and total phosphorous fluctuated from 0.01 to 0.02 mg/L during the sampling period. Microcystis spp. was identified as dominant cyanobacteria in cell density range between 176 and 226 cells/mL for both reservoirs. Amazingly, MCs were not present at detectable levels following the HPLC method (detection limit 0.5 mg/L) and ELISA method (detection limit 0.1 µg/L). Also, the PCR amplification showed the absence of mcy cluster genes E, A and B in the water samples. Thus, the results of the study revealed that both Labugama and Kalatuwawa reservoirs have non toxic strains of cyanobacterium Microcystis spp. The results of the present study were supported HPLC, ELISA analysis and molecular analysis.Item Detection of cylindrospermopsin and microcystin-LR in well water of CKDu prevalent Medirigiriya, Sri Lanka(Research Symposium on Pure and Applied Sciences, 2018 Faculty of Science, University of Kelaniya, Sri Lanka, 2018) Abeysiri, H.A.S.N.; Wanigasuriya, K.; Manage, P.M.Cyanobacterial blooms in aquatic systems have increased over recent decades. Many of the blooms are highly toxic, causing a serious hazard to human and animal health. The commonest cyanotoxins are hepatotoxins such as microcystin-LR (MC-LR) and cylindrospermopsin (CYN). Cyanotoxin has been proposed as one of the causative agents for CKDu in Sri Lanka and recent studies have revealed the contamination of drinking dug wells by toxin-producing cyanobacteria in the North Central, Uva and Eastern provinces. Thus, the present study was carried out to determine the contamination of CYN and MC-LR in randomly selected CKDu patients’ household well water. The study was carried out for both dry and wet seasons and water samples were collected from 42 wells in Medirigiriya and 21 wells from Hambanthota as a control area. Water temperature, pH, conductivity, Dissolved Oxygen (DO) were measured at the site itself using standard methods. N-NO3-, N-NO2-, N-NH3, total phosphorous and total hardness were measured by standard spectrophotometric and titrimetric methods. CYN and MC-LR quantification were done using ELISA detection kits (Beacon) (minimum detection limit 0.1 ppb). Identification and enumeration of cyanobacteria were carried out under a light microscope (×400). The results of the study revealed that all the tested general water quality parameters were within the Sri Lanka standards given for potable water. Mean cell densities of Microcystis sp. were varying during dry season from 60 ± 0.03 cells/mL to 307 ± 0.08 cells/mL and from 48 ± 0.07 cells/mL to 127 ± 0.73 cells/mL during wet season where MC-LR ranged from 0.02 to 6.73 µg/L and from 0.01 to 5.34 µg/L during dry and wet seasons respectively. Mean cell densities of Cylindrospermopsis sp. during dry and wet season ranged between 20 ± 0.02 cells/mL to 82 ± 0.29 cells/mL and 14 ± 0.19 cells/mL to 76 ± 0.78 cells/mL respectively, whereas the mean concentrations of CYN during dry and wet season was between 0.38 ± 0.01 µg/L to 1.45 ± 0.08 µg/L and 0.27 ± 0.04 µg/L to 1.25 ± 0.08 µg/L. Cyanotoxins and cyanobacteria were not recorded from well water collected from Hambanthota. Principal Component Analysis was done for cyanotoxin concentration, water quality parameters and a number of CKDu patients in the study area and shows a positive relationship between cyanotoxin in wells and CKDu patients who consume water from the wells (p<0.05).