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| 1 | Heavy Metal Bioaccumulation and Toxicity with Special Reference to Microalgae显示文摘The bioaccumulation and toxicity of heavy metals were reviewed with special reference to microalgae, the key compo- nent of the food web in aquatic ecosystems. Heavy metals enter algal cells either by means of active transport or by endocytosis through chelating proteins and affect various physiological and biochemical processes of the algae. The toxicity primarily results from their binding to the sulphydryl groups in proteins or disrupting protein structure or displacing essential elements. Metals can break the oxidative balance of the algae, inducing antioxidant enzymes, such as superoxide dismutase (SOD), glutathione peroxidase (GPX) and ascorbate peroxidase (APX). The amount of oxidized proteins and lipids in the algal cells thus indicates the severity of the stress. Algal tolerance to heavy metal is highly dependent upon the defense response against the probable oxidative damages. Pro- duction of binding factors and proteins, exclusion of metals from cells by ion-selective transporters and excretion or compartmen- talization have been suggested with regard to reducing heavy metal toxicity. However, a comprehensive description on the mecha- nisms underlining metal toxicity of microalgae and gaining tolerance is yet to be elaborated. | K. K. I. U. Arunakumara ZHANG Xuecheng | 2008 | Journal of Ocean University of China2008，7，1： | 4 |
| 2 | Heavy metal bioaccumulation and toxicity with special reference to microalgae 显示文摘 | Arunakumara K K I U Zhang X C | 2008 | Journal of Ocean University of China (Oceanic and Coastal Sea Research)2008，7，1： | 1 |
| 3 | Anti-hypercalcemic effect of orally administered recombinant Saccharomyces cerevisiae expressing salmon calcitonin on hypercalcemic rats显示文摘 | Pingnan Sun Xuecheng Zhang Xiaonan Zang Xiaoling Zhou Yunsong Chen K. K. I. U. Arunakumara Bin Liang | 2007 | Biotechnology Letters2007，，7： | 1 |
| 4 | Current status of heavy metal contamination in Asia' s rice lands 显示文摘 | Arunakumara K K I U Buddhi Charana Walpola Min - Ho Yoon | 2013 | Reviews in Environmental Science and Bio/Technology2013，12，4： | 1 |
| 5 | Bioaccumulation of Pb^(2+) and Its Effects on Growth,Morphology and Pigment Contents of Spirulina (Arthrospira) platensis显示文摘A laboratory experiment was conducted to assess the bioaccumulation of Pb2+ and its effects on growth,morphology and pigment contents of Spirulina (Arthrospira) platensis. The specimen cultured in Zarrouk liquid medium was treated with various initial metal concentrations (0,5,10,30,50 and 100 μg mL-1). The growth of S. platensis was adversely affected by Pb2+ at high con-centrations (30,50 and 100 μg mL-1). However,at low concentrations (5μg mL-1),Pb2+ could stimulate its growth slightly. The pig-ment contents (chlorophyll α and β carotene) were decreased in a dose-dependent manner. The highest reductions (67% and 53% respectively in chlorophyll α and β carotene) were observed in 100 μg mL-1treatment group. The LC50 (96 h) of Pb2+ was measured as 75.34 μg mL-1. Apart from a few cases of filament breakages at elevated concentrations (50 and 100 μg mL-1),morphological abnor-malities are not specific. Metal bioaccumulation increased with Pb2+ concentrations,but decreased with exposure time. The maxi-mum accumulated amount was 188 mg g-1 dry weight. The bioconcentration factor (BCF) reached to a peak at day 2,followed by a gradual reduction for all the exposure concentrations. S. platensis is able to tolerate considerably high Pb2+ concentrations. Conse-quently it can be used as a potential species to remove heavy metal from contaminated waters. | K. K. I. U. Arunakumara ZHANG Xuecheng SONG Xiaojin | 2008 | Journal of Ocean University of China2008，7，4： | 1 |
| 6 | Effects of heavy metals (Pb^(2+) and Cd^(2+)) on the ultrastructure, growth and pigment contents of the unicellular cyanobacterium Synechocystis sp. PCC 6803显示文摘The unicellular cyanobacterium Synechocystis sp. PCC 6803, a model organism known for its unique combination of highly desirable molecular genetic, physiological and morphological characteristics, was employed in the present study. The species was cultured in BG11 liquid medium contained various initial concentrations of Pb2+ and Cd2+ (0, 0.5, 1, 2, 4, 6 and 8 mg/L). The experiment was conducted for six days and the metal induced alterations in the ultrastructure, growth and pigment contents were assessed. Alterations in the ultrastructure of the Synechocystis sp. PCC 6803 cells became evident with the increased (>4 mg/L Pb2+) metal concentration. The photosynthetic apparatus (thylakoid membranes) were found to be the worst affected. Deteriorated or completely destroyed thylakoid membranes have made large empty spaces in the cell interior. In addition, at the highest concentration (8 mg/L Pb2+), the polyphosphate granules became more prominent both in size and number. Despite the initial slight stimulations (0.2, 3.8 and 6.5% respectively at 0.5, 1 and 2 mg/L Pb2+), both metals inhibited the growth in a dose-dependent manner as incubation progressed. Pigment contents (chlorophyll a, β carotene and phycocyanin) were also decreased with increasing metal concentration. Cells exposed to 6 mg/L Pb2+, resulted in 36.56, 37.39 and 29.34% reductions of chlorophyll a, β carotene and phycocyanin respectively over the control. Corresponding reductions for the same Cd2+concentrations were 57.83, 48.94 and 56.90%. Lethal concentration (96 h LC50) values (3.47 mg/L Cd2+ and 12.11 mg/L Pb2+) indicated that Synechocystis sp. PCC 6803 is more vulnerable to Cd2+ than Pb2+. | K. K. I. U. Arunakumara 张学成 | 2009 | Chinese Journal of Oceanology and Limnology2009，27，2： | 1 |
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