Departamento de Biologia, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto 14040-901, SP, Brazil; Universidad Regional Amazónica-IKIAM, Via Tena, Muyuna kilómetro 7, Ecuador.
Universidade Estadual Paulista, Campus de São Vicente, São Vicente 11380-972, SP, Brazil.
Comp Biochem Physiol C Toxicol Pharmacol. 2019 Sep;223:35-41. doi: 10.1016/j.cbpc.2019.05.005. Epub 2019 May 11.
This study investigates the combined effects of waterborne copper exposure and acute temperature change on oxygen consumption and the oxidative stress biomarkers, glutathione S-transferase (GST) and glutathione peroxidase (GPx), in the gills and hepatopancreas of the fiddler crab Minuca rapax. Crabs held at 25 °C were acclimated to 0 (control), 50, 250 or 500 μg Cu L for 21 days, and were then subjected to 15, 25 and 35 °C for 24 h. Aerial oxygen consumption rates of crabs in copper free media increased with increasing temperature from 15 to 35 °C, Q values reaching ≈3. Crabs exposed to increasing copper concentrations exhibited variable responses, Q values falling to ≈1.5. Copper had no effect on oxygen consumption at 25 °C. However, at 35 °C, rates decreased in a clear concentration-response manner in the copper exposed crabs, revealing impaired aerobic capability. At 15 °C, oxygen consumption rates increased with copper concentration, except for a decrease at 500 μg Cu L. Gill GST activity was ≈2-fold that of the hepatopancreas, while hepatopancreas GPx activity was 3-fold that of the gills. Gill GST activities were reduced by copper exposure only at 25 °C while hepatopancreas GST activities were altered by copper at all temperatures. Hepatopancreas GST and GPx activities increased in crabs exposed to copper at 35 °C, revealing oxidative stress induction. Hepatopancreas GST and GPx activities were reduced in copper exposed crabs at 15 °C, suggesting a diminished capability to mitigate the effects of copper exposure at low temperature. These findings reveal that copper exposure increases oxygen consumption at low temperatures but decreases consumption at high temperature. Hepatopancreas GPx activities decreased at low temperature and increased at high temperature. These novel findings demonstrate that the interaction between copper exposure and temperature should be considered when evaluating biomarker activities in semi-terrestrial crabs.
本研究调查了水合铜暴露和急性温度变化对招潮蟹鳃和肝胰腺中耗氧量和氧化应激生物标志物谷胱甘肽 S-转移酶 (GST) 和谷胱甘肽过氧化物酶 (GPx) 的联合影响。在 25°C 下饲养的螃蟹适应于 0（对照）、50、250 或 500μgCu/L 21 天，然后在 15、25 和 35°C 下暴露 24 小时。在无铜介质中，螃蟹的空气耗氧率随温度从 15°C 升高到 35°C 而增加，Q 值达到约 3。暴露于铜浓度增加的螃蟹表现出不同的反应，Q 值下降到约 1.5。在 25°C 时，铜对耗氧量没有影响。然而，在 35°C 时，暴露于铜的螃蟹的耗氧率以明显的浓度反应方式下降，表明有氧能力受损。在 15°C 时，耗氧量随铜浓度增加，除 500μgCu/L 时下降外。Gill GST 活性约为肝胰腺的 2 倍，而肝胰腺 GPx 活性是鳃的 3 倍。仅在 25°C 时，铜暴露会降低鳃 GST 活性，而在所有温度下，铜都会改变肝胰腺 GST 活性。在 35°C 下暴露于铜的螃蟹中，肝胰腺 GST 和 GPx 活性增加，表明诱导氧化应激。在 15°C 下暴露于铜的螃蟹中，肝胰腺 GST 和 GPx 活性降低，表明在低温下减轻铜暴露影响的能力下降。这些发现表明，铜暴露会增加低温下的耗氧量，但会降低高温下的耗氧量。肝胰腺 GPx 活性在低温下降低，在高温下增加。这些新发现表明，在评估半陆生螃蟹的生物标志物活性时，应考虑铜暴露与温度之间的相互作用。
