Browsing by Author "Nakisah Mat Amin"

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    Impact of mercury (II) nitrate on physiological and biochemical characteristics of selected marine algae of different classes
    (Procedia Environmental Science, 2015) Luqman Abu Bakar; Nakisah Mat Amin; Hazlina Ahamad Zakeri
    Short-term physiological and biochemical responses induced by mercury(II) nitrate (Hg(NO3)2) in three marine macroalgae, Gracilaria salicornia (Rhodophyceae), Sargassum sp. (Phaeophyceae) and Ulva reticulata (Chlorophyceae) were studied. All algae were good accumulators of Hg. However, this characteristic significantly decreases in G. salicornia and significantly increases in U. reticulata as concentration of Hg increases. Algal FV/FM, chlorophyll (chl) a content and relative growth showed a significant reduction in the presence of Hg. Hg impact was prominent in FV/FM than the other parameters while a small impact was shown by the relative growth. Hg induced synthesis of new amino acids and inhibit the production of some. The profile even changed when the concentration of Hg(NO3)2 increases.
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    Isolation of bioflocculant-producing bacteria from Penaeus vannamei ponds for the production of extracellular polymeric substances
    (AACL Bioflux, 2016) Nor A. Kasan; Mohd F. Amin Che Teh; Nurul F. Che Hashim; Zaharah Ibrahim; Nakisah Mat Amin; Nurarina A. Ghazali
    Bioflocculants are essential polymers with their flocculating activity depending on the characteristics of the secreted flocculants by bioflocculant-producing bacteria. However, the characteristics of bioflocculant produced by microorganisms were not investigated profoundly. In order to better understand these characteristics, determination of extracellular polymeric substances (EPS) from bioflocculant-producing bacteria were characterized in terms of protein concentrations. A total of 51 bioflocculant-producing bacteria isolates were screened from Pacific whiteleg shrimp, Penaeus vannamei culture ponds in Setiu, Terengganu, Malaysia. Screening of bioflocculant-producing bacteria were conducted through morphological approaches followed by protein extraction using Lowry assay method. The identified bioflocculant-producing bacteria includes Corynebacterium sp., Klebsiella sp., Lactobacillussp., Staphylococcus sp., Bacillus sp., Streptococcus sp., Vibrio spp., Neisseria sp., Serratia sp. and Yersinia sp., with the highest protein concentration of 829 mg mL-1 were attained by Staphylococcus sp. The various amounts of EPS concentration produced by different species of bacteria were dependent on their specific population growth and growth rate. Therefore, the establishment of bioflocculant-producing bacteria isolated from biofloc which showed high tendency for EPS production were performed successfully.
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    Morphological analysis on the toxic effect of manganese on Acanthamoeba sp. isolated from Setiu Wetland, Terengganu
    (Procedia Environmental Science, 2015) Fatimah Hashim; Nur Athirah Abdul Rahman; Nakisah Mat Amin
    Manganese (Mn) is one of the common pollutants found in aquatic environment that are difficult to destroy and very persistent in the water body. Excessive levels of Mn in the aquatic environment have threatened some of the aquatic organisms including free-living Acanthamoeba sp. In this study, Mn was assessed for its cytotoxicity and genotoxicity on Acanthamoeba sp. isolated from Setiu Wetland, Terengganu. IC50 value of Mn obtained was 24 ppm while morphological observation indicates that Acanthamoeba sp. underwent apoptotic and necrotic mode of cell death after exposure to Mn for 24 hours at 30°C. This metal is also able to induce mild genotoxicity towards the DNA of Acanthamoeba sp.