Browsing by Author "Noor Azhar Mohamed Shazili"

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    Putative Roles for Metallothionein and HSP70 Genes in Relation with Heavy Metal Accumulation and Parasitic Cymothoid in the Fish Nemipterus furcosus
    (Archives of Environmental Contamination and Toxicology, 2016) Do Dinh Thinh; Mohamad Hafiz Farhan Abdul Rasid; Zulaikha Mat Deris; Noor Azhar Mohamed Shazili; Gudrun De Boeck; Li Lian Wong
    To assess stress level induced by multiple stressors in aquatic organism, biomarkers have been adopted as early warning indicator due to their high accuracy, rapidity, and sensitivity. We investigated the effects of ectoparasitic isopod infection on heavy metal bioaccumulation (Fe, Cu, Zn, and Cd) in the fish Nemipterus furcosus and profiled the expression of metallothionein (MT) and heat shock proteins 70 (HSP70) genes of the fish host. Sixty individuals (parasitized and nonparasitized with Cymothoa truncata) were collected from three sites differing in the levels of anthropogenic activities off the South China Sea. Our results revealed no significant difference in heavy metal concentrations between infected and nonparasitized fish. We observed a positive correlation between heavy metal bioaccumulation in the fish host and anthropogenic activities. Accordingly, expression analysis of MT genes in fish liver showed significant differences in expression level between sampling sites, with lowest level in the least exploited site (Batu Rakit). A reverse pattern in HSP70 gene expression was demonstrated in fish muscle, showing the highest expression at Batu Rakit. While cymothoid infection in N. furcosus had no significant impact on fish MT gene expression, it resulted in a reduction of HSP70 level in liver of parasitized fish. These findings highlight the putative roles of MT in heavy metal assessment. Future studies should determine the kinetics of cymothoid infection and other potential stressors in characterizing the HSP70 gene expression profile.
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    The Spatial Distribution Of Al, Fe, Cu, Cd And Pb In The Surface Sediment Of Brunei Bay, Borneo During The Southwest And Northeast Monsoons
    (Journal of Sustainability Science and Management, 2016) Adiana Ghazali; Noor Azhar Mohamed Shazili; Joseph Bidai; Hasrizal Shaari
    A geochemical assessment of Al, Fe, Cu, Cd and Pb was carried out for the surface sediment of Brunei Bay. Samples were collected during July 2013 and January 2014 representing the Southwest and Northeast Monsoon respectively. Fe, Pb, Al and Cu were high in July 2013 samples whereas Cd had a similar range of concentration during both sampling periods. Cd showed no particular spatial distribution pattern whereas Fe and Pb were highly distributed at the transect stations compared to the coastal stations due to the river flushed out. In contrast, Al and Cu were uniformly distributed between all stations. The Al, Fe and Pb in Brunei Bay sediment were dominantly bound to the mineral fraction which is also an indicator of natural sources whereas Cu was more dominant in the ion exchangeable fraction which is the most bioavailable fraction.
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    Trace metals, grain size and organic matter in sediment from a coastal area of Thailand and Malaysia
    (Aquatic Ecosystem Health and Management, 2016) Siriporn Pradit; Noor Azhar Mohamed Shazili; Prawit Towatana; Wuttipong Saengmanee
    The sediment of Pattani Bay in Thailand and the Setiu Wetlands in Malaysia was investigated in the dry and wet seasons of 2014 to evaluate levels of trace metal concentrations (As, Cd, Cu, Pb, and Zn), sediment grain size, and organic matter. The mean concentrations of all the elements in both seasons (dry and wet) at Pattani Bay were higher than those in the Seitu Wetlands. High levels of As were detected in both seasons, but they were classified as moderately polluted in the dry season. The Enrichment Factor in relation to aluminum showed significant (Enrichment Factor >5 in the wet season) anthropogenic activity as related input for As in both areas and for Pb at Pattani Bay. Surprisingly, the metal concentrations (As, Cu, Pb, and Zn) were only significantly (p < 0.01, p < 0.05) correlated with clay content in the dry season at Pattani Bay. Silt-clay content and the amount of organic matter at Pattani Bay were higher than those of the Setiu Wetlands.