Histophagous ciliate Pseudocollinia brintoni and bacterial assemblage interaction with krill Nyctiphanes simplex. II. Host responses

Diseases of Aquatic Organisms

Alejandro López-Cortés¹  Nelly Tremblay¹  Carlos J. Robinson¹  Jaime Gómez-Gutiérrez¹  Jorge A. Del Angel-Rodríguez¹  Tania Zenteno-Savín¹  Mario J. Aguilar-Méndez¹ 

关键词: Apostome ciliates;    Euphausiacea;    Parasite-host association;    Fatty acids;    Oxidative stress;    Eicosapentaenoic acid;    Docosahexaenoic acid;    Glutathione S-transferase;   

DOI  :  10.3354/dao02923

学科分类：生物科学（综合）

来源: Inter-Research

【 摘 要 】

ABSTRACT: Unlike decapod crustaceans of commercial interest, the krill defense system and its response to parasites and pathogens is virtually unknown. Histophagous ciliates of the genus Pseudocollinia interact with at least 7 krill species in the northeastern Pacific. Although they can cause epizootic events, the physiology of the histophagous ciliate-host interaction and krill (host) defenses remain unknown. From 1 oceanographic survey along the southwestern coast of the Baja California Peninsula near Bahía Magdalena and 2 in the Gulf of California, we investigated parasitoid-host physiological responses (fatty acid and oxidative stress indicators) of the subtropical krill Nyctiphanes simplex infected with the ciliate P. brintoni. All life stages of P. brintoni were associated with opportunistic bacterial assemblages that have not been explicitly investigated in other Pseudocollinia species (P. beringensis, P. oregonensis, and P. similis). Parasitoid ciliates exclusively infected adult females, which showed increased lipid content during gonad development. As the infection progressed, omega-3 eicosapentaenoic and docosahexaenoic fatty acids, which may act as energy sources to produce high numbers of ciliate transmission stages, were quickly depleted. Antioxidant enzymes, components of the crustacean defense system, varied throughout infection, but without inhibiting Pseudocollinia infection, i.e. higher levels of lipid oxidative damage were detected in late stages of infection. The ineffective response of the krill antioxidant defense system against histophagous ciliates and the bacteria associated with the ciliates suggests that Pseudocollinia ciliates are functionally analogous to krill predators and may have a strong influence on the population dynamics of krill.

【 授权许可】

Unknown