用分子遗传学及免疫学方法控制鱼类寄生性甲藻

寄生性甲藻,例如Amyloodiniumocellatum,给鱼类养殖带来严重的危害。虽然,近年来针对Amyloodinium的药物治疗有一些新的进展,如使用氯喹、过氧化氢和3,N泛影葡胺拉沙洛西等,然而,含铜类药物仍然是最有效的。近年来分子遗传学和免疫学的进展,使得我们能够更好地了解寄生性甲藻的流行病学及其防治方法。分子系统学研究认为某些寄生性甲藻,如Amyloodiniumocellatum,可以聚类为高度同源性的一支;而其它的如Piscinoodiniumpillulare,则可以认为不止一种或更高的分类阶元。这些分子分析也发展出一些高灵敏的检测技术,可以检测出环境中极少量的寄生性甲藻。通过对Amyloodinium的免疫学研究表明,鱼类能对寄生物的感染产生强烈的高度特异的保护性免疫应答,其中主要是抗体介导的免疫应答。鱼体皮肤和鳃也能表达内源非特异性多肽抗生素(类组蛋白),它们能对Amyloodinium造成致命的破坏。利用这些特异或非特异的免疫防御,将更有助于我们控制这些具有严重危害性的寄生性甲藻

Controlling parasitic dinoflagellates of fish, with special emphasis on molecular genetics and immunity

Parasitic dinoflagellates, as exemplified by the marine pathogen Amyloodinium ocellatum, cause major losses in cultured fish. Some new treatments for Amyloodinium have emerged in recent years, including chloroquine, hydrogen peroxide and 3,N-methylglucamine lasalocid. However, copper remains the most useful treatment. Recent advances in molecular genetics and immunology have the potential to greatly enhance our understanding of the epidemiology and control of these important pathogens. Molecular phylogenetic analyses suggest that some parasitic dinoflagellates (e.g., Amyloodinium ocellatum) might form a highly homogeneous taxon while others (e.g., Piscinoodinium pillulare) probably constitute more than one species or even higher taxa. These molecular analyses have also allowed the development of highly sensitive probes that can detect very small numbers of parasites in environmental samples. Studies of the immune response to Amyloodinium have revealed that fish can mount a strong and highly protective specific response to parasite exposure. A significant part of this response is mediated by antibody. Fish also constitutively express endogenous, host-produced polypeptide antibiotics (histone-like proteins) in the skin and gills that are highly lethal to Amyloodinium at concentrations that are well within the levels present in host tissues. Utilization of these specific and nonspecific defenses has the potential to greatly enhance our ability to protect against these devastating pathogens.