网状原角藻在种间相互作用下的生长及产毒变化研究

Effect of interspecies competition on the growth and toxin production of Protoceratiumreticulatum

虾夷扇贝毒素(Yessotoxins,YTXs)是近十年来在我国沿海城市贝类样品中检测出的海洋赤潮毒素物质,能危害人类健康。本研究选取产YTXs的网状原角藻(Protoceratiumreticulatum)作为研究对象,通过不同方式将其与常见赤潮硅藻——拟旋链角毛藻(Chaetocerospseudocurvisetus)混合培养,对比单独培养条件下网状原角藻的细胞比生长率、体积比生长率、所产毒素组成以及单细胞毒素含量等指标,研究种间作用对网状原角藻生长和产毒的影响。结果表明,直接培养条件下,不同接种密度,拟旋链角毛藻的生长都会被网状原角藻不同程度的抑制,而间接接触培养条件下,网状原角藻的生长受培养环境的影响较大,因此在其生长、运动空间严重受限制的条件下,其生长反而被拟旋链角毛藻抑制。在各混合培养体系中,网状原角藻的体积变化并不显著,其分泌的YTX毒素组分差异也不明显,可见该藻并不是通过体积增大或者毒素分泌增加来提高其竞争优势的。本研究对于探索赤潮发生原因,加强赤潮预警具有重要意义。

Yessotoxins(YTXs) are one group of marine toxins documented in shellfish samples collected in coastal cities of Chinalast decade, which can be accumulated in filtration-feeding bivalves and then threathuman health. In this study, wefocused onthe growth and toxin-production of Protoceratiumreticulatum, a main YTXsproducer, when it interacts with common harmful diatom, Chaetoceroscurvisetus. Results indicated that when they were co-cultured, the growth of C.curvisetus was inhibited by P.reticulatumto different extents, which depends on the proportionof their initial cell density. However, limited space suppressed the growth of P. reticulatum while C.curvisetus grew well under indirect contact condition in the co-culture container. As the volume and toxin-production were not changed significantly, increases of the volume and YTXs amount were not the main ways of P.reticulatum to get its competitive advantages. Our findings highlighted YTXs seafood safety concerns by exploring harmful algal causes and strengthening early warning systems.