Hydrogen sulphide sensitivity and tolerance in genetically distinct lineages of a selfing mangrove fish (Kryptolebias marmoratus)

Mitochondrial physiology and responses to elevated hydrogen sulphide in two isogenic lineages of an amphibious mangrove fish

“…For example, mobile animals (e.g. teleost fishes) leave areas with elevated H 2 S (Abel et al, 1987;Rossi et al, 2019;Martin and Currie, 2020) whereas sessile organisms such as bivalves can close exposed biological membranes and rely on anaerobic metabolism (Vismann, 1991) )] (Soleyma velum, Cavanaugh, 1983;Olavius algarvensis, Dubilier et al, 2001). Lastly, H 2 S can be detoxified internally through sulphur oxidation into less toxic byproducts (i.e.…”

“…Similar to P. mexicana, the amphibious mangrove rivulus (Kryptolebias marmoratus) lives in a sulphidic environment (native mangrove forests), resulting in constant exposure to fluctuating levels of H 2 S ranging from 0 to 1116 µmol l −1 (Rossi et al, 2019). Mangrove rivulus show a remarkable tolerance for H 2 S, surviving both short-term (>20 min) exposure to ∼2500-3500 µmol l −1 H 2 S and long-term (3 days) exposure to 200 µmol l −1 H 2 S (Cochrane et al, 2019;Martin and Currie, 2020). Importantly, mangrove rivulus are hermaphroditic, and capable of self-fertilization, allowing for the production of isogenic lineages from a single parental genotype to study genetic differences of phenotypic traits (Tatarenkov et al, 2010).…”

“…As in P. mexicana (Tobler et al, 2008;Greenway et al, 2020), there are differences in responses to H 2 S among isogenic lineages of amphibious rivulus. Mangrove rivulus from the Honduras lineage are more sensitive to H 2 S, emerging from water at lower H 2 S concentrations compared with the Belize lineage (Martin and Currie, 2020). We are only beginning to understand the behavioural and physiological strategies used by mangrove rivulus to tolerate its sulphide-rich habitat.…”

“…We are only beginning to understand the behavioural and physiological strategies used by mangrove rivulus to tolerate its sulphide-rich habitat. To date, these strategies include avoidance/ limited body exposure (Abel et al, 1987;Rossi et al, 2019;Martin and Currie, 2020) and modified H 2 S-resistant haemoglobin (Cochrane et al, 2019), but these cannot fully explain their H 2 S tolerance. Genetically distinct sub-populations of fish serve as critical tools for studying the adaptation of organisms to extreme environments (Tobler et al, 2018), but we do not know what physiological mechanisms may determine the observed differences in isogenic lineages in mangrove rivulus.…”

“…Given that we have no information on basic mitochondrial physiology in this species, our first experimental series was aimed at characterizing the overall mitochondrial oxidizing capacities of liver in the two lineages. Because of recently observed differences in H 2 S tolerance between the Belize and the Honduras lineages (Martin and Currie, 2020), we predicted divergent oxidizing capacities resulting in metabolic differences in aerobic and anaerobic capacities. In the second experimental series, we measured the kinetics of apparent H 2 S mitochondrial oxidation and its inhibitory effects on respiration in the two lineages.…”