Extracellular and Mixotrophic Symbiosis in the Whale-Fall Mussel Adipicola pacifica: A Trend in Evolution from Extra- to Intracellular Symbiosis
نویسندگان
چکیده
BACKGROUND Deep-sea mussels harboring chemoautotrophic symbionts from hydrothermal vents and seeps are assumed to have evolved from shallow-water asymbiotic relatives by way of biogenic reducing environments such as sunken wood and whale falls. Such symbiotic associations have been well characterized in mussels collected from vents, seeps and sunken wood but in only a few from whale falls. METHODOLOGY/PRINCIPAL FINDING Here we report symbioses in the gill tissues of two mussels, Adipicola crypta and Adipicola pacifica, collected from whale-falls on the continental shelf in the northwestern Pacific. The molecular, morphological and stable isotopic characteristics of bacterial symbionts were analyzed. A single phylotype of thioautotrophic bacteria was found in A. crypta gill tissue and two distinct phylotypes of bacteria (referred to as Symbiont A and Symbiont C) in A. pacifica. Symbiont A and the A. crypta symbiont were affiliated with thioautotrophic symbionts of bathymodiolin mussels from deep-sea reducing environments, while Symbiont C was closely related to free-living heterotrophic bacteria. The symbionts in A. crypta were intracellular within epithelial cells of the apical region of the gills and were extracellular in A. pacifica. No spatial partitioning was observed between the two phylotypes in A. pacifica in fluorescence in situ hybridization experiments. Stable isotopic analyses of carbon and sulfur indicated the chemoautotrophic nature of A. crypta and mixotrophic nature of A. pacifica. Molecular phylogenetic analyses of the host mussels showed that A. crypta constituted a monophyletic clade with other intracellular symbiotic (endosymbiotic) mussels and that A. pacifica was the sister group of all endosymbiotic mussels. CONCLUSIONS/SIGNIFICANCE These results strongly suggest that the symbiosis in A. pacifica is at an earlier stage in evolution than other endosymbiotic mussels. Whale falls and other modern biogenic reducing environments may act as refugia for primal chemoautotrophic symbioses between eukaryotes and prokaryotes since the extinction of ancient large marine vertebrates.
منابع مشابه
The influence of nutritional conditions on metal uptake by the mixotrophic dual symbiosis harboring vent mussel Bathymodiolus azoricus.
The vent mussel Bathymodiolus azoricus, host thioautotrophic and methanotrophic bacteria, in their gills and complementary, is able to digest suspended organic matter. But the involvement of nutritional status in metal uptake and storage remains unclear. The influence of B. azoricus physiological condition on its response to the exposure of a mixture of metals in solution is addressed. Mussels ...
متن کاملتأثیر میزان فاصله از رودخانه بر خصوصیات فیزیکی و شیمیایی، کلنیزاسیون و اسپورزایی قارچهای میکوریز اربوسکولار همزیست با درختچه گز (Tamarix arceuthoides)
Salt cedar is widely spread out in most part of the country but there is lack of information about its symbiosis with arbuscular mycorrhizal fungi. Then, the main objective of this study was to evaluate the symbiosis of AMF with salt cedar and its affectability by distance from river and soil physiochemical properties. For this purpose, riparian Maroon forest width was divided to three location...
متن کاملThe Symbiosis of Human and Semantic Technology Through the Lens of Actor-Network Theory
Background: Semantic technologies (STs) have made machine reasoning possible by providing intelligent data management methods. This capability has created new forms of interaction between humans and STs, which is called "semantic interaction." The increasing spread of this form of interaction in daily life reveals the need to identify the factors affecting it and introduce the requirements of...
متن کاملNon-biological gene carriers designed for overcoming the major extra- and intracellular hurdles in gene delivery, an updated review
Gene therapy as a modern therapeutic approach has not yet advanced to a globally-approved therapeutic approach. Lack of adequate reliable gene delivery system seems to be one of the major reasons from the pharmaceutical biotechnology point of view. Main obstacles delaying successful application of human gene therapy are presented in this review. The unique advantages of non-biological gene carr...
متن کاملNew insights into symbiotic associations between ants and bacteria.
Many ants live in complex mutualistic or parasitic relationships with other insects or plants, some of which are classical examples of the mutual benefit of symbiosis. However, only in the past few years have new insights into the symbiosis of ants and microorganisms been reported. Examples are the symbiosis of ants of the genus Camponotus with intracellular bacteria present in their midgut, an...
متن کامل