Allelopathy of the raphidophyte Heterosigma akashiwo against the dinoflagellate Akashiwo sanguinea is mediated via allelochemicals and cell contact
Allelopathy of the raphidophyte Heterosigma akashiwo against the dinoflagellate Akashiwo sanguinea is mediated via allelochemicals and cell contact
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DOI：
10.3354/meps09476
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发表时间：
2012-02
影响因子：
2.5
通讯作者：
Xuchun Qiu;Y. Yamasaki;Y. Shimasaki;Hiroaki Gunjikake;Masato Honda;Mayumi Kawaguchi;T. Matsubara;S. Nagasoe;T. Etoh;S. Matsui;T. Honjo;Y. Oshima
中科院分区：
文献类型：
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作者：
Xuchun Qiu;Y. Yamasaki;Y. Shimasaki;Hiroaki Gunjikake;Masato Honda;Mayumi Kawaguchi;T. Matsubara;S. Nagasoe;T. Etoh;S. Matsui;T. Honjo;Y. Oshima
通过无菌条件下的双藻培养实验，研究了藻类植物赤潮异弯藻与血红甲藻之间的生长交互作用。赤潮假单胞菌(初始细胞密度：1×102或1×104个细胞ml�-1)对血吸虫有致死作用，初始细胞密度为1×102个/ml�-1。当赤潮杆菌和血吸虫的初始细胞密度分别为1×1 0 2和2×10 3个细胞ml�1时，两种细菌的生长同时受到抑制。一个数学模型被用来模拟双藻培养中的生长和相互作用。该模型预测，假以时日，赤潮将胜过赤潮。用赤潮藻高密度培养制备的无细胞浓缩滤液降低了血吸虫的最大生长速度和最大产量。用同样的方法制备的金线莲滤液只降低了赤潮鱼的最大产量，但不影响其最大生长速度。接触条件下双藻培养的血吸虫生长显著低于单藻培养和非接触条件下的双藻培养。在细胞直接接触条件下，当血吸虫与赤潮杆菌共同培养时，形态异常的血吸虫细胞出现频率较高。此外，赤潮假单胞菌产生的化感物质(包括化感物质多糖蛋白复合体)以浓度依赖的方式诱导血吸虫生长抑制和形态异常细胞的形成。这些结果表明，赤潮异弯藻通过化感物质和直接接触细胞的生长抑制作用，影响了赤潮病菌田间开花的形成。
Growth interactions between the raphidophyte Heterosigma akashiwo and the dinoflagellate Akashiwo sanguinea were examined by using bi-algal culture experiments under axenic conditions. There was a lethal effect of H. akashiwo (initial cell density: 1 × 10 2 or 1 × 10 4 cells ml �1 ) on A. sanguinea at an initial cell density of 1 × 10 2 cells ml �1 . Growth of both species was suppressed concurrently when initial cell densities of H. akashiwo and A. sanguinea were 1×1 0 2 and 2 × 10 3 cells ml �1 , respectively. A mathematical model was used to simulate growth and interactions in bi-algal cultures. The model predicted that H. akashiwo would outcompete A. san- guinea over time. A cell-free enriched filtrate prepared from dense culture of H. akashiwo reduced both maximum growth rate and maximum yield of A. sanguinea. A filtrate of A. san- guinea prepared in the same manner only reduced maximum yield of H. akashiwo but did not affect its maximum growth rate. Growth of A. sanguinea in bi-algal cultures under contact condi- tions was significantly lower than that in mono-algal culture and in bi-algal cultures under non- contact conditions. Morphologically abnormal A. sanguinea cells occurred at high frequency only when A. sanguinea was cultured together with H. akashiwo under direct cell contact condition. Moreover, growth inhibition and formation of morphologically abnormal cells of A. sanguinea were induced in a concentration-dependent manner by allelochemicals (including allelochemical polysaccharideprotein complexes) produced by H. akashiwo. These results suggest that growth inhibition effects, via allelochemicals and direct cell contact by Heterosigma akashiwo, influence bloom formation of Akashiwo sanguinea in the field.