Symbioses between marine nematodes and sulfur-oxidizing chemoautotrophic bacteria

Autor(en)
Jörg Ott, Monika Bright, Silvia Bulgheresi
Abstrakt

Over the course of evolutionary history nematodes and sulfur-oxidizing chemoautotrophic bacteria have formed symbiotic relationships in marine sediments on at least two independent occasions. Mouthless worms of the genus Astomonema have endosymbionts which live intracellularly or extracellularly in the gut rudiment of their host. The ultrastructure of the bacteria and the ecology of the symbiosis are strong indications for a chemoautotrophic nature of the microorganisms; the lack of feeding structures in the host suggests a nutritive dependence on the microbes. In the Stilbonematinae, bacteria cover the outside of the body in a characteristic, species-specific pattern. Ultrastructure, incorporation of inorganic carbon and the presence of RuBisCo and key enzymes of sulfide oxidation pathways show the bacteria to be sulfur-oxidizing chemolithoautotrophs. Stable isotope analysis suggests that the worms depend on the bacteria for their nutrition. In turn, they provide the microorganisms with sulfide and oxygen by repeatedly migrating through the chemocline in sheltered sediments.

Organisation(en)
Journal
Symbiosis
Band
36
Seiten
103-126
Anzahl der Seiten
24
ISSN
0334-5114
Publikationsdatum
2004
Peer-reviewed
Ja
ÖFOS 2012
1060 Biologie
Link zum Portal
https://ucris.univie.ac.at/portal/de/publications/symbioses-between-marine-nematodes-and-sulfuroxidizing-chemoautotrophic-bacteria(fb1d5fc8-ce35-4d8a-8c95-2cdcbba08d14).html