Intestinal ciliates of cockroaches and their methanogenic endosymbionts; evolutionary aspects
van Hoek, A.H.A.M., van Alen, T.A., Hackstein, J.H.P., Vogels, G.D.
Dept. of Microbiology & Evolutionary Biology, Fac. Sci., University of Nijmegen,
NL-6525 ED Nijmegen, The Netherlands
Anaerobic ciliates, belonging to the genus Nyctotherus, occur in the hindgut of those cockroach species that also harbour intestinal methanogenic archaea. Differences in the galvanotactic behaviour, the morphology of the ciliates, and the shape of their endosymbiotic methanogenic archaea suggested that the various cockroach strains hosted different ciliates. By PCR-amplification of the small subunit of the ribosomal genes, restriction analysis and DNA sequencing it was possible to unravel the evolutionary relationships between hosts and symbionts. DNA sequence analysis of the ribosomal repeat and restriction analysis of PCR-amplified rDNA genes showed that intestinal ciliates and their endosymbiotic archaea were specific for the particular host strain. In contrast to the situation in aphids with their eubacterial endosymbionts [2], the phylogeny of the intestinal ciliates and their cockroach hosts does not match. Further evolutionary implications of the results will be discussed.
[1] Hackstein, J. H. P. (1997) Antonie van Leeuwenhoek 72: 63-76
[2] Moran, N.A. (1996) Proc. Natl. Acad. Sci. USA. 93: 2873-2878
| LOCATION |
DATE |
TIME |
| Lecture Hall I |
Wednesday, April 8 |
09:55 am |