Fabri Leonardo M, Garçon Daniela P, Moraes Cintya M, Pinto Marcelo R, McNamara John C, Leone Francisco A
Departamento de Bioquímica e Imunologia, Faculdade de Medicina de Ribeirão Preto, Brazil.
Universidade Federal do Triângulo Mineiro, Campus Universitário de Iturama, 38280-000, Brazil.
Comp Biochem Physiol B Biochem Mol Biol. 2023 Oct-Dec;268:110880. doi: 10.1016/j.cbpb.2023.110880. Epub 2023 Jul 28.
This investigation examines the kinetic characteristics and effect of acclimation to a brackish medium (21 ‰S) on gill V(H)-ATPase activity in two hololimnetic populations of M. amazonicum. We also investigate the cellular immunolocalization of the enzyme. Immunofluorescence findings demonstrate that the V(H)-ATPase c-subunit is distributed in the apical pillar cells of shrimps in fresh water but is absent after acclimation to 21 ‰S for 10 days. V(H)-ATPase activity from the Tietê River population is ≈50% greater than the Grande River population, comparable to a wild population from the Santa Elisa Reservoir, but is 2-fold less than in cultivated shrimps. V(H)-ATPase activity in the Tietê and the Grande River shrimps is abolished after 21 ‰S acclimation. The apparent affinities of the V(H)-ATPase for ATP (0.27 ± 0.04 and 0.16 ± 0.03 mmol L, respectively) and Mg (0.28 ± 0.05 and 0.14 ± 0.02 mmol L, respectively) are similar in both populations. The absence of V(H)-ATPase activity in salinity-acclimated shrimps and its apical distribution in shrimps in fresh water underpins the importance of the crustacean V(H)-ATPase for ion uptake in fresh water.
本研究考察了亚马逊沼虾两个全湖种群对微咸介质（盐度21‰）的适应对鳃V（H）-ATP酶活性的动力学特征及影响。我们还研究了该酶的细胞免疫定位。免疫荧光结果表明，V（H）-ATP酶c亚基分布于淡水虾的顶端柱状细胞中，但在适应21‰盐度10天后消失。蒂埃特河种群的V（H）-ATP酶活性比格兰德河种群高约50%，与圣伊丽莎水库的野生种群相当，但比养殖虾低2倍。蒂埃特河和格兰德河虾在适应21‰盐度后，V（H）-ATP酶活性消失。两个种群中V（H）-ATP酶对ATP（分别为0.27±0.04和0.16±0.03 mmol/L）和Mg（分别为0.28±0.05和0.14±0.02 mmol/L）的表观亲和力相似。盐度适应虾中V（H）-ATP酶活性的缺失及其在淡水虾中的顶端分布，突出了甲壳类V（H）-ATP酶在淡水离子摄取中的重要性。
