tailieunhanh - Oceanography and Marine Biology: An Annual Review (Volume 42) - Chapter 4

Sự đa dạng của cộng sinh thiotrophic được tìm thấy trong các sinh cảnh biển giàu sunfua, liên quan đến phyla nhau protists và động vật không xương sống, cũng như một số phân khu của Proteobacteria. Trong khi đó, một số cộng sinh tốt hơn được biết đến là phát triển cao endosymbioses, ectosymbioses nguyên thủy hơn là ít được biết đến. Lưu huỳnh-chemolithotrophic oxy hóa tự nhiên của vi khuẩn và tầm quan trọng dinh dưỡng của họ cho các máy chủ eukaryote đã được chứng minh cho Kentrophoros ciliates spp. niveum Zoothamnium, phân họ Stilbonematinae giun tròn,. | MARINE MICROBIAL THIOTROPHIC ECTOSYMBIOSES J. OTT M. BRIGHT S. BULGHERESI Institute of Ecology and Conservation Biology University of Vienna Althanstrasse 14 A-1090 Vienna Austria E-mail Abstract A high diversity of thiotrophic symbioses is found in sulphide-rich marine habitats involving several phyla of protists and invertebrates as well as several subdivisions of the Proteo-bacteria. Whereas some of the better-known symbioses are highly evolved endosymbioses the more primitive ectosymbioses are less well known. The sulphur-oxidising chemolithotrophic nature of the bacteria and their nutritive importance to the eukaryote host have been demonstrated for the ciliates Kentrophoros spp. and Zoothamnium niveum the nematode subfamily Stilbonematinae and the carid shrimp Rimicaris exoculata. For a number of other regular bacteria-eukaryote associations such a symbiotic relationship has been hypothesised based on ecological morphological physiological or molecular data but is still inconclusive. The diversity of thiotrophic symbioses The interest in thiotrophic symbioses awakened by the discovery of the deep-sea hydrothermal vents has led to the discovery of an unexpected diversity of microbe animal relationships in a variety of habitats from the intertidal zone to the deep sea Cavanaugh 1985 Fisher 1990 Nelson Fisher 1995 . The fascination of food chains that operate without sunlight and the opportunity to find clues about the origin of life on this and probably other celestial bodies Farmer 1998 have spurred research on hot vents and cold seeps in the deep sea and on continental slopes. In the wake of these expensive endeavours research has been conducted in more easily accessible shallowwater sulphidic habitats and has revealed a comparable variety of symbiotic relationships Ott 1996 Giere 1992 . The deep-sea communities are unrivalled with regard to the importance that the thiotrophic symbioses play in an extremely food-limited setting. In .