“Open wide!" effects of air and hydrogen sulphide acclimation on buccal cavity tissue structure in an amphibious fish
LE3 .A278 2020
Bachelor of Science
Phenotypic plasticity occurs in many organisms and supports the development of alternate phenotypes in different environments. Mangrove rivulus (Kryptolebias marmoratus) is a neotropical amphibious fish exposed to high concentrations of hydrogen sulphide, normally toxic, in its mangrove environment. This fish can be aerially exposed for months and is capable of cutaneous respiration, a plastic trait, supplemented by air gulping. We tested the effects of air (3d, 7d) and 3d aquatic hydrogen sulphide (H2S) exposure on the tissue structure of the buccal cavity (mouth) and skin, and specifically, on the number of mucus cells. Results demonstrated a significant increase in the number of mucus cells in the buccal cavity epithelium in the 3 and 7-day air acclimation, as well as in the 3-day H2S group. No significant differences in mucus cells were detected in the skin (epidermis) when the fish were exposed to 3 and 7 days of air acclimation, or to the 3-day H2S acclimation. This study suggests that tissues of the buccal cavity acclimate quickly to air and aquatic H2S and supports the hypothesis that air gulping is an important behaviour during aerial exposure.
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