Monari Marta, Matozzo Valerio, Foschi Jurgen, Cattani Otello, Serrazanetti Gian Paolo, Marin Maria Gabriella
Department of Biochemistry G. Moruzzi, University of Bologna, Via Tolara di Sopra 50, 40064 Ozzano Emilia, Bologna, Italy.
Fish Shellfish Immunol. 2007 Jan-Feb;22(1-2):98-114. doi: 10.1016/j.fsi.2006.03.016. Epub 2006 Apr 25.
The effects of high temperatures on the clam, Chamelea gallina, generally recognised as a low tolerant bivalve species, were studied by evaluating some functional responses of the haemocytes. The animals were kept for 7days at 20, 25 and 30 degrees C and total haemocyte count (THC), phagocytosis, lysozyme activity (in both haemocyte lysate and cell-free haemolymph), activity and expression of the antioxidant enzyme superoxide dismutase (SOD) (in both haemocyte lysate and cell-free haemolymph) were chosen as biomarkers of exposure to high temperatures. The survival-in-air test was also performed. During the experiment, the clams showed differing burrowing behaviour: the animals kept at 20 and 25 degrees C burrowed completely, whereas at 30 degrees C the clams progressively emerged from the sediment and then remained on the surface. The highest temperature significantly increased THC, whereas it decreased the phagocytic activity of haemocytes. The haemocyte size frequency distribution in clams kept at 30 degrees C showed that the cell population of about 8-10microm was markedly reduced compared to clams kept at 20 and 25 degrees C. In clams maintained at 25 degrees C, lysozyme activity was significantly increased in haemocyte lysate, whereas it was markedly decreased in cell-free haemolymph. Total SOD activity significantly decreased in haemocytes from clams held at 30 degrees C whereas it increased in cell-free haemolymph from clams held at 25 degrees C and 30 degrees C. A significant decrease in haemocyte Mn-SOD and Cu/Zn-SOD activities was found with increasing temperature. In cell-free haemolymph, the highest Mn-SOD activity was recorded at 30 degrees C, whereas the Cu/Zn-SOD activity showed no significant changes in clams maintained at different temperatures. SOD isoform expression exhibited different patterns in haemocyte lysate and cell-free haemolymph. The resistance to air exposure of clams kept at 30 degrees C was shown to decrease significantly, LT(50) values fell from 6days in clams kept at 20 degrees C and 25 degrees C to 4days in those kept at 30 degrees C.
高温对通常被认为是耐受力较低的双壳贝类——加利福尼亚沙海螂的影响，通过评估血细胞的一些功能反应来进行研究。将这些动物分别在20、25和30摄氏度下饲养7天，并选择总血细胞计数（THC）、吞噬作用、溶菌酶活性（在血细胞裂解物和无细胞血淋巴中）、抗氧化酶超氧化物歧化酶（SOD）的活性和表达（在血细胞裂解物和无细胞血淋巴中）作为高温暴露的生物标志物。还进行了空气中存活试验。在实验过程中，蛤蜊表现出不同的挖掘行为：饲养在20和25摄氏度的动物完全钻入沙中，而在30摄氏度时，蛤蜊逐渐从沉积物中钻出，然后停留在表面。最高温度显著增加了总血细胞计数，而降低了血细胞的吞噬活性。在30摄氏度下饲养的蛤蜊的血细胞大小频率分布表明，与饲养在20和25摄氏度的蛤蜊相比，约8 - 10微米的细胞群体明显减少。在25摄氏度下饲养的蛤蜊中，血细胞裂解物中的溶菌酶活性显著增加，而在无细胞血淋巴中则显著降低。在30摄氏度下饲养的蛤蜊的血细胞中，总SOD活性显著降低，而在25摄氏度和30摄氏度下饲养的蛤蜊的无细胞血淋巴中，总SOD活性增加。随着温度升高，血细胞中的锰超氧化物歧化酶（Mn - SOD）和铜/锌超氧化物歧化酶（Cu/Zn - SOD）活性显著降低。在无细胞血淋巴中，30摄氏度时记录到最高的Mn - SOD活性，而在不同温度下饲养的蛤蜊中，Cu/Zn - SOD活性没有显著变化。SOD同工型表达在血细胞裂解物和无细胞血淋巴中表现出不同的模式。结果表明，饲养在30摄氏度的蛤蜊对空气暴露的抵抗力显著下降，半数致死时间（LT(50)）值从饲养在20和25摄氏度的蛤蜊的6天降至饲养在30摄氏度的蛤蜊的4天。
