Investigations on life-cycle and host specificity of the Malacosporea (Myxozoa) Daniel Grabner betreut durch Prof. Dr. Bernd Sures (Univ. Duisburg-Essen) und Prof. Dr. Mansour El-Matbouli (Vetmeduni Wien)
Introduction Fish-malacospores Parasite development The Metazoan phylum Myxozoa comprises about 2,000 mostly fish-parasitic species. Typical for this group are life-cycles involving a Spores are released infect bryozoans in kidney of fish vertebrate and an invertebrate host. Transmission from one host to the other is achieved by water-born spores. Within the Myxozoa, the via the urine to water class Malacosporea is the most enigmatic and probably most ancient group. These parasites are known to infect fish and freshwater bryozoans, though most malacosporeans have been described only in the invertebrate host. The only complete malacosporean life-cycle is Resistence? known for Tetracapsuloides bryosalmonae, the parasite causing proliferative kidney disease (PKD) in salmonid fish. This disease can lead to Which Further life high losses in aquaculture and might also threaten wild populations of brown trout (Salmo trutta). Besides the genus Tetracapsuloides hosts? with only a single species, the Malacosporea also contain the genus Buddenbrockia with two described species. Buddenbrockia spp. are cycles? Release of known only from the bryozoan host where they either form sac-like stages similar to T. bryosalmonae or worm-like, motile stages. Where? spores to Knowledge about host spectrum, transmission mechanisms and intra-specific differences in susceptibility to malacosporean parasites are Mechanism? water scarce. Therefore, it was the aim of the present study to investigate biology and life-cycles of some malacosporeans more intensively. Spores infect fish Laboratory cycle of T. bryosalmonae Transmission experiments
pike not infected at all (!?!)
brown trout infected and transmitted stages of T. T. bryoslamonae to bryosalmonae brook trout Bryozoa
rainbow trout As a basis for this work, infected but no parasite a laboratory culture of stages developed in infected Bryozoa bryozoans was estab- grayling bryozoans lished from field sam- Bryozoa-spore of ples. T. bryosalmonae
Diversity of malacosporeans Resistance of rainbow trout lineages
stages of Buddenbrockia plumatellae in Comparison of 4 rainbow trout bryozoans and brown trout for their sus- developmental stages of Budden- ceptibility to T. bryosalmonae brockia sp. in carp kidney by quantitative real-time PCR.
Brown trout (BT) were found to be most susceptible, while one rainbow trout lineage (WT) showed slower increase of parasite numbers than others. A new Buddenbrockia species?!? We can be infected Route of entry into fish host by B. plumatellae!! Molecular phylogeny of known malacosporeans The penetration of T. bryosalmonae spores Presence of infective into the fish was beginning penetration stages reveal gill to be Dr. rer. nat. Daniel Grabner (Dipl. Biol.) investigated by in-situ of spores into gill tissue the dominant portal hybridization of entry for the parasite. 1999-2005 Studium der Biologie an der Eberhard- Karls-Universität Tübingen 2006-2010 Promotion an der Universität Duisburg- Essen, praktische Durchführung der Arbeit an der Tierärztlichen Fakultät der Ludwig-Maximilian-Universität in München und der Veterinärmedizinischen Universität Wien 2010-2011 Stipendium der Japanese Society for Promotion of Science an der Universität von Tokyo Scanning electron microscopy of bryozoa-spores of T. bryosalmonae allow further insights in seit Mai 2011 wiss. Mitarbeiter im Fachgebiet Angewandte spore morphology Zoologie/Hydrobiologie der Universität Duisburg-Essen