Physiology and ecology of ciguatera causative dinoflagellates

研究了日本冲绳岛赤岛底栖鞭毛类生物的分布，其中包括雪卡毒素致病菌。包括一个新种在内的原心种的密度比其他种高。甘比铁饼毒是CTX和MTX的主要产生源，其密度较低，但其最大细胞密度比冲绳岛和石垣岛检测的细胞密度高1000倍。该新种类似于proorocentrum emarginatum，但通过扫描电镜观察证实了瓣膜形状和瓣膜表面凹陷的差异。研制了一种监测底栖鞭毛藻生长的新型荧光仪。在积分球中放置培养管，使激发光和体内荧光同时扩散。因此，在不搅拌的情况下监测荧光。利用积分球荧光计（ISF）对底栖硅藻和鞭毛藻的培养物进行了性能测试，并在体内荧光与提取的叶绿素量之间获得了良好的相关性。研究了光照、温度和大型藻类分泌物对底栖原心藻生长的影响。在1.1 ~ 1.4 × 10^<16>量子之间，cm^<-2>, sec^<-1>，以及25.5 ~ 30.7个规格之间，其生长最佳。褐藻科褐带菌和卧棘棘菌表面释放的分泌物对lima、P. sp.、P. emarginatum的生长有促进作用，而对concavum的生长有促进作用。与此相反，在野外观察到大量原心黏附的鸟Turbinaria ornata的分泌物对四种植物的生长有较大的干扰。从这些结果来看，除了提供促进生长的物质外，它们对宿主巨体的粘附的好处被认为是对高辐照的遮荫。

Distribution of benthic dinoflagellates including ciguatera causative organisms were examined in Akajima Island, Kerama Islands, Okinawa, Japan. Prorocentrum species including a new species occupied high percentage of density compared with others. Gambierdiscus toxicus known as a main producer of CTX and MTX was rater low in the density, but its maximum cell density was a thousand times higher than that examined at Okinawa Island and Ishigaki Island. The new species recembles Prorocentrum emarginatum but the difference in the valval shape and depression on the valve surface were confirmed by scanning electron microscopic observations.A new type of fluorometer was made to monitor the growth of benthic dinoflagellates. A culture tube is placed in the integrating sphere which diffuse both excitation light and in vivo fluorescence. Thus the fluorescence is monitored without agitation. The performance of integrating-sphere-fluorometer (ISF) was tested for cultures of a benthic diatom and dinoflagellates, and good correlations were obtained between in vivo fluorescence and extracted chlorophyll amounts.Effects of light, temperature and exudate of macroalgae on growth of benthic Prorocentrum species were examined. Their optimum growth were observed between 1.1-1.4x10^<16>quanta cm^<-2> sec^<-1> and 25.5-30.7 ﾟC, respectively. The exudate released from the surface of Zonaria stipitata and Distromium decumbens (Phaeophyceae) promoted the growth of P. lima, P. sp. and P. emarginatum but P. concavum. On the contrary, the exudate of Turbinaria ornata, on which abundant adhesion of Prorocentrum was observed in the field, rather disturbed the growth of four species. From these results, benefits of their adhesion to the host macroalge were thought as a shading from high irradiance besides the supply of growth promoting substances.