Browsing by Author "NAKISAH MAT AMIN"

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    GENOTOXIC EFFECTS OF MERCURY AND ZINC ON Acanthamoeba sp., A FREE -LIVING AMOEBA FROM SETIU WETLANDS WATER
    (Journal of Sustainability Science and Management, 2009) NAKISAH MAT AMIN; SYAFAZ-SYAZWANI SIDEK; ANTONINA ABDULLAH
    Heavy metals are stable in the environment and cannot be degraded or destroyed so they tend to build up in the atmosphere, soils, sediments and water. Excessive levels of metals in our environment will contribute pollution and pose a risk to humans and other living things, including Acanthamoeba. Acanthamoeba spp are free-living amoebae that are in abundance, especially in the aquatic environment. Their role as mainly a bacterial consumer indicates their importance in the food-web cycle of the ecosystem. Previous studies showed that heavy metals, like cadmium, lead, mercury and zinc, inhibited the growth ofAcanthamoeba spp. Therefore, the objectives of the present study were to examine further the effects ofmercury and zinc on Acanthamoeba sp, an amoeba isolated from water in Setiu Wetlands, by looking at the level ofDNA damage in the amoeba cells. The amoebae were exposed to five different concentrations of the metals for 72h before the cytotoxic and genotoxic effects on the amoebae were observed. The IC50 values ofmercury and zinc against the amoeba obtained in this study were 1.10 ppm and 39.00 ppm, respectively. The DNA damage with various score levels inAcanthamoeba cells by different concentrations ofmercury and zinc treatment are presented and discussed.
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    THE IDENTIFICATION AND DISTRIBUTION OF NAKED AMOEBAE IN THE WATER AND SEDIMENTS OF SETIU WETLANDS, TERENGGANU
    (Journal of Sustainability Science and Management, 2008) NAKISAH MAT AMIN; PON CHEE KEONG; CHOI KAM SHING
    This study was carried out to obtain preliminary data on the amoeba species present in brackish water and sediments at Setiu Wetlands, Terengganu. Water and sediment samples from seven sampling locations in Setiu Wetlands were taken for isolation and identifcation of the amoebae. The water samples were collected between 5 to 10 cm below the water surface level in sterile 500 mL polyethelene bottles and were fltered through a membrane fltration unit to trap the amoebae. Sediment samples were taken using a shovel grab and were vortex-mixed in Page’s amoeba Solution (PaS) to separate the amoebae from the sediments. Estimation on their abundance in the sediments at each location was done following Singh’s method with modifcations. The texture of the sediments was also analyzed and correlated with amoeba abundance. The results of this study indicated that at least four species of amoebae were isolated and identifed in water at Setiu Wetlands. They were Acanthamoeba polyphaga, Acanthamoeba sp., Vahlkamfa sp. and one unidentifed species designated as amoeba A. In sediments of Setiu Wetlands, at least seven species of amoebae were present. They were Acanthamoeba polyphaga, Acanthamoeba sp., Vahlkamfa sp., Mayorella sp., Vannella-like amoeba, amoeba a and amoeba B. The amoeba species that were labeled as amoeba a and B could not be assigned to any genera of amoebae since their morphological characteristics did not ft the standard taxonomic keys for free-living naked amoebae. The most common amoeba found both in water and sediments in Setiu Wetlands belongs to the genus of Acanthamoeba. The amoeba distribution and abundance in relation to the sediment texture and water quality are discussed.
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    PROTEINS EXPRESSION IN Acanthamoeba castellanii AFTER EXPOSURE TO AMMONIUM CHLORIDE
    (Journal of Sustainability Science and Management, 2011) NAKISAH MAT AMIN; THUNISHAA VEERAPPEN; SITI FAEZAH SIDEK
    The aquatic environment is easily contaminated with ammonium from the release of biological wastes that contain ammonium into rivers and oceans by urban and agricultural run-off and this affects the life of aquatic organisms, including small, free-living naked amoebae such as Acanthamoeba spp. These amoebae are common in water and, being single-cell organisms, they can easily respond to any changes in the environment, such as ammonium contamination, by expressing specific proteins known as biomarkers which can be suggested as a new tool for rapid diagnosis and monitoring of environmental health hazard. In this study, Acanthamoeba castellanii was treated with different concentrations of ammonium chloride (NH4Cl) and the cytotoxicity of ammonium chloride on the amoeba and its IC 50 were examined and determined. The treated amoebae were also subjected to 2-D electrophoresis for protein profile analysis. The IC50 of NH4Cl against A. castellanii obtained in this study was 0.64 mg/mL. In the protein profile analysis, the total number of protein spots that were consistently observed in control Acanthamoeba were 93, and the number of these spots decreased as the concentration of NH4Cl used increased. Besides that, some newly-expressed protein spots were observed in treated Acanthamoeba. Degradation of certain proteins and synthesis of new proteins in treated Acanthamoeba observed in the present study may be indicative of cellular stress and these proteins can be used as biomarkers to access ammonium contamination in the aquatic environment for preventive measures.