Effects of arsenate on the growth and microcystin production of Microcystis aeruginosa isolated from Taiwan as influenced by extracellular phosphate

Please use this identifier to cite or link to this item: http://ir.lib.ncu.edu.tw/handle/987654321/28288

Title:	Effects of arsenate on the growth and microcystin production of Microcystis aeruginosa isolated from Taiwan as influenced by extracellular phosphate
Authors:	Gong,Y;Chou,HN;Tu,CD;Liu,X;Liu,JT;Song,LR
Contributors:	中央大學
Keywords:	CYANOBACTERIAL TOXINS;PUBLIC-HEALTH;CHLORELLA SP;TOXICITY;ACCUMULATION;TOLERANCE;NITROGEN;PHYTOPLANKTON;COMMUNITIES;INHIBITION
Date:	2009
Issue Date:	2010-06-29 19:45:32 (UTC+8)
Publisher:	化學研究所
Abstract:	Arsenic pollution and eutrophication are both prominent issues in the aquaculture ponds of Taiwan. It is important to study the effects of arsenic on algal growth and toxin production in order to assess the ecological risk of arsenic pollution, or at least to understand naturally occurring ponds. The sensitivity of algae to arsenate has often been linked to the structural similarities between arsenate and phosphate. Thus, in this study we examined the effects of arsenate (10(-8) to 10(-4) M) on Microcystis aeruginosa TY-1 isolated from Taiwan, under two phosphate regimes. The present study showed that M. aeruginosa TY-1 was arsenate tolerant up to 10(-4) M, and that this tolerance was not affected by extracellular phosphate. However, it seems that extracellular phosphate contributed to microcystin production and leakage by M. aeruginosa in response to arsenate. Under normal phosphate conditions, total toxin yields after arsenate treatment followed a typical inverted U-shape hormesis, with a peak value of 2.25 +/- 0.06 mg L-1 in the presence of 10(-7) M arsenate, whereas 10(-8) to 10(-6) M arsenate increased leakage of similar to 75% microcystin. Under phosphate starvation, total toxin yields were not affected by arsenate, while 10(-6) and 10(-5) M arsenate stimulated microcystin leakage. It is suggested that arsenate may play a role in the process of microcystin biosynthesis and excretion. Given the arsenic concentrations in aquaculture ponds in Taiwan, arsenate favors survival of toxic M. aeruginosa in such ponds, and arsenate-stimulated microcystin production and leakage may have an impact on the food chain.
Relation:	JOURNAL OF APPLIED PHYCOLOGY
Appears in Collections:	[Graduate Institute of Chemistry] journal & Dissertation

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