DAO 116:227-236 (2015)  -  DOI: https://doi.org/10.3354/dao02923

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

Jaime Gómez-Gutiérrez1,*, Jorge A. Del Angel-Rodríguez2,4, Nelly Tremblay1,5, Tania Zenteno-Savín2, Mario J. Aguilar-Méndez2,6, Alejandro López-Cortés2, Carlos J. Robinson

1Instituto Politécnico Nacional, Centro Interdisciplinario de Ciencias Marinas (CICIMAR), Departamento de Plancton y Ecología Marina, La Paz, BCS 23096, Mexico
2Centro de Investigaciones Biológicas del Noroeste (CIBNOR), La Paz, BCS 23096, Mexico
3Instituto de Ciencias del Mar y Limnología, Universidad Nacional Autónoma de México (UNAM), Mexico City, DF 04510, Mexico
4Present address: Departments of Biology and Ocean Sciences, Memorial University of Newfoundland, St. John’s, NL A1C 5S7, Canada
5Present address: Instituto Politécnico Nacional, Centro de Investigación y de Estudios Avanzados (CINVESTAV)— Unidad Mérida, Departamento de Recursos del Mar, Mérida, Yucatán 97310, Mexico
6Present address: Instituto Politécnico Nacional, Unidad Profesional Interdisciplinaria de Ingeniería Guanajuato (UPIIG), Guanajuato 36275, Mexico
*Corresponding author:

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.


KEY WORDS: Apostome ciliates · Euphausiacea · Parasite-host association · Fatty acids · Oxidative stress · Eicosapentaenoic acid · Docosahexaenoic acid · Glutathione S-transferase


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Cite this article as: Gómez-Gutiérrez J, Del Angel-Rodríguez JA, Tremblay N, Zenteno-Savín T, Aguilar-Méndez MJ, López-Cortés A, Robinson CJ (2015) Histophagous ciliate Pseudocollinia brintoni and bacterial assemblage interaction with krill Nyctiphanes simplex. II. Host responses. Dis Aquat Org 116:227-236. https://doi.org/10.3354/dao02923

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