Thiotaurine and hypotaurine contents in hydrothermal‐vent polychaetes without thiotrophic endosymbionts: correlation With sulfide exposure

Abstract

Invertebrates at hydrothermal vents and cold seeps must cope with toxic H(2)S. One proposed protection mechanism involves taurine derivatives: At vents and seeps, many animals have high levels of hypotaurine and thiotaurine (a product of hypotaurine and HS), originally found in animals with thiotrophic endosymbionts. To further test the role of these compounds, we analyzed them in vent polychaetes without endosymbionts: Paralvinella sulfincola, P. palmiformis and P. pandorae (paralvinellids) and Nicomache venticola (maldanid). P. sulfincola were collected from a high temperature (42-68 degrees C) and a warm site (21-35 degrees C). P. palmiformis and pandorae were from cool sites (12-18 degrees C) and N. venticola were from a cold site (4 degrees C). H(2)S concentrations in vent effluent largely correlate with temperature. Some specimens were frozen; other ones were kept alive in laboratory chambers, with and without sulfide. Tissues were analyzed for taurine derivatives and other solutes that serve as organic osmolytes. The major osmolyte of all species was glycine. Thiotaurine contents were significantly different among all species, in the order P. sulfincola hot>P. sulfincola warm>P. pandorae>P. palmiformis>N. venticola. P. sulfincola also had high levels of sarcosine; others species had none. Sarcosine and hypotaurine contents of P. sulfincola's branchiae were higher, while glycine contents were lower, than in main body. In P. palmiformis kept in pressure chambers with sulfide, thiotaurine contents were higher and hypotaurine lower than in those kept without sulfide. These results support the hypothesis that conversion of hypotaurine to thiotaurine detoxifies sulfide in vent animals without endosymbionts.

The taurine biosynthetic pathway of microalgae

“…O. tauri, marine microalgae, was used for the study of effects of various sulfur compounds on growth and taurine synthesis because it is a broadly distributed marine species [34,35] that might encounter environments containing high sulfur compounds. For example, the presence of large amounts of hypotaurine and thiotaurine (a derivative of taurine, which serves as an organic osmolyte) has been shown in invertebrates growing in sulfide rich environments near hydrothermal vents and cold seeps of the deep oceans [36]. O. tauri tolerated five of ten sulfur compounds but only one of them, sulfate increased taurine levels.…”

Cysteine dioxygenase and cysteine sulfinate decarboxylase genes of the deep-sea mussel Bathymodiolus septemdierum: possible involvement in hypotaurine synthesis and adaptation to hydrogen sulfide

“…Hypotaurine is a precursor of taurine and is contained in tissues of various mollusks (Ouchi 1959). Thiotaurine is a substance generated by the reaction of sulfide and hypotaurine (Yancey et al 2009). …”

“…The use of hypotaurine and thiotaurine has been suggested to be one of the major mechanisms for adaptation to sulfide exposure (Pruski and Fiala-Médioni 2003;Rosenberg et al 2006;Brand et al 2007;Ortega et al 2008;Yancey et al 2009). Hypotaurine is a precursor of taurine and is contained in tissues of various mollusks (Ouchi 1959).…”

Paracoccus denitrificans PD1222 Utilizes Hypotaurine via Transamination Followed by Spontaneous Desulfination To Yield Acetaldehyde and, Finally, Acetate for Growth

“…A higher reactivity of the HT-sulfinate group than of the taurine-sulfonate group under physiological conditions is reflected in the functions of HT to detoxify sulfide in deep-sea invertebrates (45)(46)(47)(48) and to act as an antioxidant and free-radical-trapping agent in mammalian cells (49,50). However, HT is stable under the conditions that we used, i.e., in oxic culture medium.…”