Hypotaurine and sulfhydryl-containing antioxidants reduce H2S toxicity in erythrocytes from a marine invertebrate

Abstract

SUMMARYHypotaurine (HT) has been proposed to reduce sulfide toxicity in some deep-sea invertebrates by scavenging free radicals produced from sulfide oxidation or by scavenging sulfide via the reaction of HT with sulfide, forming thiotaurine (ThT). We tested whether HT or several antioxidants could reduce the total dissolved sulfide concentration in buffered seawater exposed to H 2 S, and whether HT, ThT or antioxidants could increase the viability of Glycera dibranchiata erythrocytes exposed to H 2 S in vitro. We found that 5 and 50 mmol l -1 HT reduced the dissolved sulfide in cell-free buffer exposed to H 2 S by up to 80% whereas the antioxidants glutathione ethyl ester (GEE) ), which contain sulfhydryl groups, increased cell viability during H 2 S exposure but to a lesser extent than HT whereas ASC, Tempol and Trolox, which do not contain sulfhydryl groups, decreased viability or had no effect. These data show that HT can protect cells from sulfide in vitro and suggest that sulfide scavenging, rather than free radical scavenging, is the most important mechanism of protection.,

Inhibition of the oxidative stress response by heat stress inCaenorhabditis elegans

“…Worms were exposed to the pro-oxidants by adding 25 μl of 2× working stock 1:1 by volume to wells of the 384-well plate. The plates were then covered with gas-permeable sealing tape and transferred into air-tight aluminum incubation chambers described previously (Ortega et al, 2008). The chambers were placed on a shaker table in a large incubator at 20, 25, 30 or 35°C, with thermosensor data loggers (ibutton, Maxim Integrated, San Jose, CA, USA) used to monitor temperatures.…”

“…After 4 h, the pro-oxidants were removed by serial dilution with NGM buffer using a 16-channel microplate washer (ELx50, BioTek Instruments, Winooksi, VT, USA) and the 384-well plates were placed in recovery condition (20°C, unfed). After 16 h, the worms were then imaged at 30× magnification using an automated epifluorescence microscope and CCD camera system described previously (Ortega et al, 2008). The images were later analyzed manually, with worms being scored as alive if they appeared sinusoidal and scored as dead if they appeared straight and rigid (Moy et al, 2009).…”

Multiple stressor interactions influence embryo development rate in the American horseshoe crab, Limulus polyphemus

“…Upon establishing the final salinity, the multiwell plates requiring hypoxic conditions were placed into custom-made gas-tight chambers (Ortega et al, 2008), which were then filled with a combination of O 2 and N 2 gas to achieve 5% or 13% O 2 , as appropriate. Multiwell plates assigned to 21% O 2 were not placed into gas-tight chambers but instead were sealed with Parafilm to limit evaporation.…”

The metabolic demands of endosymbiotic chemoautotrophic metabolism on host physiological capacities

“…They have considerably lower rates of CO 2 and O 2 uptake and take up oxygen through their proportionally much smaller plumes and sulfide through their posterior extensions, which have been dubbed 'roots' (Freytag et al, 2001;Julian et al, 1999;Ortega et al, 2008). Their environment is stable and depletion of sulfide around the roots probably limits their autotrophic potential, though they do transport the end product of sulfur oxidation, sulfate, back into the sediment to further stimulate sulfide generation by sulfate-reducing bacteria (Cordes et al, 2003;Dattagupta et al, 2008;Dattagupta et al, 2006).…”