de Lima Tábata Martins, de Ramos Bruna, de Souza Tavares Margarita, Leidens Danusa, Ayres Bruna Soares, Maciel Fábio Everton, Nery Luiz Eduardo Maia
Programa de Pós-Graduação em Ciências Fisiológicas, Instituto de Ciências Biológicas, Universidade Federal do Rio Grande, FURG, Av. Itália, Km 8, Rio Grande, RS 96201-300, Brazil.
Programa de Pós-Graduação em Gerenciamento Costeiro, Instituto de Oceanografia, Universidade Federal do Rio Grande, FURG, Av. Itália, Km 8, Rio Grande, RS 96201-300, Brazil.
Comp Biochem Physiol A Mol Integr Physiol. 2021 Feb;252:110835. doi: 10.1016/j.cbpa.2020.110835. Epub 2020 Nov 2.
Climate changes affecting aquatic environments are increasing, and the resultant environmental challenges require animals to adopt alternative compensatory behavioral and physiological strategies. In particular, low levels of dissolved O are a regular problem for estuarine animals, leading to activation of a series of behavioral and physiological responses. This study on the semi-terrestrial crab Neohelice granulata examined patterns of emersion behavior under different levels of dissolved O availability and the role of lactate in this behavior. Emersion behavior was recorded for 4.5 h for crabs in water at four different levels of dissolved O (6, 3, 2, and 1 mg O/L) and with free access to air. Oxygen consumption and hemolymphatic lactate levels were measured using the same experimental design. Emersion behavior was also recorded for 70 min in normoxic water after lactate or saline injections. Crabs increased their emersion behavior only in severe hypoxia (1 mg O/L), and O consumption decreased under more severe hypoxic conditions. Despite the increase in emersion behavior, which leads to higher O availability, an increase in hemolymphatic lactate levels indicates that the animals still need to resort to anaerobic pathways to fulfill their metabolic demand. Furthermore, animals injected with lactate showed higher emersion behaviors than animals injected with a saline solution even in normoxia. These results suggest that the increase in hemolymphatic lactate can act directly or indirectly as a trigger for the increase in emersion behavior in the semi-terrestrial crab N. granulata.
影响水生环境的气候变化正在加剧，由此带来的环境挑战要求动物采取替代性的补偿行为和生理策略。特别是，溶解氧含量低是河口动物经常面临的问题，会引发一系列行为和生理反应。本研究以半陆生蟹粒突新海伦蟹为对象，考察了在不同溶解氧可利用水平下的出洞行为模式以及乳酸在该行为中的作用。在溶解氧含量分别为4个不同水平（6、3、2和1毫克氧/升）且可自由接触空气的水中，对蟹的出洞行为进行了4.5小时的记录。采用相同的实验设计测量了耗氧量和血淋巴乳酸水平。在注射乳酸或生理盐水后，在常氧水中对出洞行为也进行了70分钟的记录。蟹只在严重缺氧（1毫克氧/升）时增加出洞行为，在更严重的缺氧条件下耗氧量降低。尽管出洞行为增加会带来更高的氧可利用性，但血淋巴乳酸水平的升高表明动物仍需借助无氧途径来满足其代谢需求。此外，即使在常氧条件下，注射乳酸的动物比注射生理盐水的动物表现出更高的出洞行为。这些结果表明，血淋巴乳酸的增加可直接或间接触发半陆生蟹粒突新海伦蟹出洞行为的增加。
