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, Tena, Ecuador.
Comp Biochem Physiol C Toxicol Pharmacol. 2019 Feb;216:93-100. doi: 10.1016/j.cbpc.2018.11.012. Epub 2018 Nov 16.
The mudflat fiddler crab Minuca rapax, typical of mangroves and intertidal zones in the Western Atlantic Ocean, responds to fluctuations in environmental parameters by biochemical and physiological adjustments. Such biochemical effects are commonly employed in environmental studies as biomarkers of estuarine contamination. This study evaluates biochemical responses in the gills and hepatopancreas of M. rapax in situ from localities exhibiting different types and levels of contamination, against a backdrop of fluctuations in environmental parameters like salinity and temperature common to estuarine regions. The biochemical biomarkers metallothionein (MT)-like protein titers and glutathione S-transferase (GST), glutathione peroxidase (GPx) and acetylcholinesterase (AChE) activities were used to evaluate responses to environmental contamination and seasonal changes in environmental parameters. Crabs were collected during two seasons, the austral winter and summer, at three sites along the coast of the state of São Paulo, Brazil that present decreasing degrees of environmental contamination: Ilha Diana, Santos (ID) > Rio Itapanhaú, Bertioga (RI) > Picinguaba, Ubatuba (P), a pristine control site. Our findings show that MT were induced in crabs from the contaminated sites (ID and RI) mainly during winter, revealing the activation of detoxification mechanisms; however MT were also induced in P crabs during the summer rainy season. GPX, GST and AChE activities were altered in P crabs during summer and in ID and RI crabs in winter. While enzyme activities in summer crabs may reflect seasonal changes in precipitation and salinity, in winter these altered activities appear to reflect contamination, although an effect of environmental parameters cannot be excluded. These findings reveal a strong seasonal influence on biochemical biomarker responses in Minuca rapax, a relevant factor to consider when interpreting the impact of environmental contamination in estuaries.
泥滩招潮蟹 Minuca rapax 是西大西洋红树林和潮间带的典型物种，通过生化和生理调节来应对环境参数的波动。这种生化效应通常被用于环境研究，作为河口污染的生物标志物。本研究评估了在不同类型和污染水平的地点，原位的 M. rapax 鳃和肝胰腺的生化反应，这些地点的环境参数如盐度和温度波动是河口地区的常见现象。使用金属硫蛋白（MT）样蛋白滴度和谷胱甘肽 S-转移酶（GST）、谷胱甘肽过氧化物酶（GPx）和乙酰胆碱酯酶（AChE）活性等生化标志物来评估对环境污染的反应以及环境参数的季节性变化。在巴西圣保罗州沿海的三个地点（Ilha Diana，Santos [ID] > Rio Itapanhaú，Bertioga [RI] > Picinguaba，Ubatuba [P]）采集了两种季节（冬季和夏季）的螃蟹，这些地点的环境污染程度逐渐降低。我们的研究结果表明，主要在冬季，污染地区（ID 和 RI）的螃蟹中 MT 被诱导，揭示了解毒机制的激活；然而，P 区的螃蟹在夏季雨季也诱导了 MT。夏季 P 区螃蟹的 GPX、GST 和 AChE 活性发生改变，冬季 ID 和 RI 区螃蟹的这些酶活性也发生改变。虽然夏季螃蟹的酶活性可能反映了降水和盐度的季节性变化，但冬季这些改变的活性似乎反映了污染，尽管不能排除环境参数的影响。这些发现揭示了 Minuca rapax 生化标志物反应的强烈季节性影响，这是在解释河口环境污染的影响时需要考虑的一个重要因素。
