Lovett D L, Verzi M P, Clifford P D, Borst D W
Department of Biology, The College of New Jersey, Ewing, NJ 08628-0718, USA.
Comp Biochem Physiol A Mol Integr Physiol. 2001 Feb;128(2):299-306. doi: 10.1016/s1095-6433(00)00308-1.
The salinity of estuarine environments can vary widely, exposing resident organisms to considerable osmotic stress. The green crab Carcinus maenas is well known for its ability to osmoregulate in response to such stress. Therefore, we tested the relationship between osmoregulation and hemolymph levels of methyl farnesoate (MF), a compound previously shown to rise in response to various types of environmental stresses. When crabs were transferred from 100% seawater to dilute (hypo-osmotic) seawater, hemolymph osmolality dropped rapidly, reaching an acclimation level 48 h after transfer. Hemolymph levels of MF also rose in these animals after a delay of 6 h, and reached a maximum level at 48 h. MF levels remained elevated as long as the crabs were maintained in dilute seawater, and quickly returned to basal levels when the animals were returned to full strength seawater. In most (but not all) animals, MF levels were elevated when hemolymph osmolality fell below the isosmotic point (approx. 800 mOsm/kg). These data suggest that MF may have a role in osmoregulation by this species. In addition, the elevation of MF by hypo-osmotic seawater suggests an experimental strategy for manipulating MF levels in crustaceans.
河口环境的盐度变化很大，使栖息在其中的生物面临相当大的渗透压力。绿蟹（Carcinus maenas）以其在应对这种压力时进行渗透调节的能力而闻名。因此，我们测试了渗透调节与法尼酸甲酯（MF）血淋巴水平之间的关系，此前有研究表明，该化合物会因各种类型的环境压力而升高。当螃蟹从100%海水转移到稀释（低渗）海水中时，血淋巴渗透压迅速下降，转移后48小时达到适应水平。这些动物的MF血淋巴水平在延迟6小时后也有所上升，并在48小时达到最高水平。只要螃蟹饲养在稀释海水中，MF水平就会保持升高，而当动物回到全强度海水中时，MF水平会迅速恢复到基础水平。在大多数（但不是所有）动物中，当血淋巴渗透压降至等渗点（约800 mOsm/kg）以下时，MF水平会升高。这些数据表明，MF可能在该物种的渗透调节中发挥作用。此外，低渗海水使MF升高，这为操纵甲壳类动物的MF水平提供了一种实验策略。
