Zheng T L, Su J Q, Maskaoui K, Yu Z M, Hu Z, Xu J S, Hong H S
School of Life Sciences, Xiamen University, Xiamen 361005, China.
Mar Pollut Bull. 2005;51(8-12):1018-25. doi: 10.1016/j.marpolbul.2005.02.039. Epub 2005 Apr 20.
The effect of S10, a strain of marine bacteria isolated from sediment in the Western Xiamen Sea, on the growth and paralytic shellfish poison (PSP) production in the alga Alexandrium tamarense (A. tamarense) was studied under controlled experimental conditions. The results of these experiments have shown that the growth of A. tamarense is obviously inhibited by S10 at high concentrations, however no evident effect on its growth was observed at low concentrations. Its PSP production was also inhibited by S10 at different concentrations, especially at low concentrations. The toxicity of this strain of A. tamarense is about (0.95-12.14) x 10(-6) MU/cell, a peak toxicity value of 12.14 x 10(-6) MU/cell appeared on the 14th day, after which levels decreased gradually. The alga grew well in conditions of pH 6-8 and salinities of 20-34 per thousand. The toxicity of the alga varied markedly at different pH and salinity levels. Toxicity decreased as pH increased, while it increased with salinity and reached a peak value at a salinity of 30 per thousand, after which it declined gradually. S10 at a concentration of 1.02 x 10(9) cells/ml inhibited growth and the PSP production of A. tamarense at different pH and salinity levels. S10 had the strongest inhibitory function on the growth of A. tamarense under conditions of pH 7 and a salinity of 34 per thousand. The best inhibitory effect on PSP production by A. tamarense was at pH 7, this inhibitory effect on PSP production did not relate to salinity. Interactions between marine bacteria and A. tamarense were also investigated using the flow cytometer technique (FCM) as well as direct microscope counting. S10 was identified as being a member of the genus Bacillus, the difference in 16S rDNA between S10 and Bacillus halmapalus was only 2%. The mechanism involved in the inhibition of growth and PSP production of A. tamarense by this strain of marine bacteria, and the prospect of using it and other marine bacteria in the bio-control of red-tides was discussed.
研究了从厦门西海域沉积物中分离出的一株海洋细菌S10，在可控实验条件下对塔玛亚历山大藻（A. tamarense）生长及麻痹性贝类毒素（PSP）产生的影响。这些实验结果表明，高浓度的S10能显著抑制塔玛亚历山大藻的生长，而低浓度时对其生长无明显影响。不同浓度的S10对其PSP产生也有抑制作用，尤其是低浓度时。该株塔玛亚历山大藻的毒性约为(0.95 - 12.14)×10(-6) MU/细胞，在第14天出现峰值毒性值12.14×10(-6) MU/细胞，之后逐渐下降。该藻在pH值为6 - 8、盐度为20‰ - 34‰的条件下生长良好。藻的毒性在不同pH和盐度水平下有显著差异。毒性随pH升高而降低，随盐度升高而增加，在盐度为30‰时达到峰值，之后逐渐下降。浓度为1.02×10(9) 细胞/ml的S10在不同pH和盐度水平下均能抑制塔玛亚历山大藻的生长及PSP产生。S10在pH值为7、盐度为34‰的条件下对塔玛亚历山大藻生长的抑制作用最强。对塔玛亚历山大藻PSP产生的最佳抑制效果出现在pH值为7时，这种对PSP产生的抑制作用与盐度无关。还利用流式细胞仪技术（FCM）以及直接显微镜计数研究了海洋细菌与塔玛亚历山大藻之间的相互作用。S10被鉴定为芽孢杆菌属的成员，S10与嗜盐芽孢杆菌的16S rDNA差异仅为2%。讨论了该株海洋细菌抑制塔玛亚历山大藻生长及PSP产生的作用机制，以及利用它和其他海洋细菌进行赤潮生物防治的前景。
