动物血清刺激下的有毒甲藻生长研究(英文)

Stimulation of P fiesteria piscicida (Dinophyceae) Growth by Animal Sera

目前有关Pfiesteria piscicida Steindinger et Burkholder的摄食行为研究已有相当多的报道，然而这种生物是如何应用蛋白的还没有人做过研究．我们研究了P．piscicida依赖于血清蛋白的生长能力，发现不管添不添加其捕食者Rhodomonas sp．，仅仅1h后，添加了动物血清的实验组就比未添加血清的对照组显示出明显出更快的生长速率，这种活跃的生长至少持续了4h．当添加了异硫氰酸荧光素的共扼免疫蛋白后，在P．piscicida的细胞中检测到了荧光；第1个小时只能检测到微弱的荧光。此后荧光逐渐增强，到3～4h达到最强．此外．我们还进一步通过蛋白质印迹法来验证P．piscicida细胞对血清蛋白质的吸收．本研究首次提供了沟鞭藻能够消化利用蛋白质的直接证据，并且发现P．piscicida生长响应与动物蛋白的添加几乎是同步的．尽管细胞快速生长机制还有待进一步研究。但我们的发现可能解释了P．piscicida是如何得益于其吞噬摄食方式及如何在鱼类出现时作出快速反应的．

Previous studies reveal various feeding behaviors in Pfiesteria piscicida Steindinger et Burkholder. However,whether this organism is able to utilize proteins has not been investigated. In this study, capability of P. piscicida to grow on serum proteins was demonstrated. Cultures amended with animal sera, with or without supply of Rhodornonas sp. as prey,exhibited significantly higher growth rate than the controls that received no sera. P. piscicida growth was observed as soon as one hour after serum addition, and active growth lasted for at least 4 hours. When provided immunoglobulin conjugated to fluorescein isothiocyanate （FITC） ,fluorescence was observed from P. piscicida cells; it was barely detectable in P. piscicida cells in the first hour but increased to a maximum in 3-4 hours. Uptake of serum proteins by P. piscicida cells was further verified by western blotting, This study provides the first direct evidence that dinoflagellates are capable of ingesting and utilizing proteins,and that P. piscicida growth responds to animal sera almost instantly, While the cell cycle mechanism for the rapid growth response remains to be investigated,the observation may explain how P. piscicida benefits from myzocytotic feeding and responds rapidly to presence of live fish.