Hamza-Chaffai A, Amiard-Triquet C, El Abed A
IPEIS, BP 805, 3000 Sfax, Tunisia.
Arch Environ Contam Toxicol. 1997 Jul;33(1):53-62. doi: 10.1007/s002449900223.
The aim of this work was to assess the relative importance of natural fluctuations in metallothionein-like protein (MTLP) levels associated with the sexual status of fish versus fluctuations due to metal exposure. In order to see fluctuations due to metal exposure, comparisons were made on the same fish species Scorpaena porcus sampled in polluted and unpolluted sites. The hermaphrodite fish Serranus scriba and Scorpaena porcus, in which sexes are separate, were compared at the unpolluted site to see fluctuations caused by the sexual status. In both species, metals and the MTLP levels were determined in the gills and liver. In these organs, Cd, Cu, and Zn distributions were examined in different fractions: the insoluble fraction (IF) and the cytosol divided into thermolabile compounds (HDF) and the heat stable compounds including MTLP. MTLP levels were higher in the liver (3.09 mg/g in S. porcus, 1.59 mg/g in S. scriba) than in gills (0.13 mg/g in S. porcus, 0.40 mg/g in S. scriba). For Scorpaena porcus, metals and MTLP levels varied with sex, whereas in Serranus scriba, which is a hermaphrodite species, inherent variations were also observed. At the polluted site, MTLP, Cd, and Cu concentrations in the gills of S. porcus increased but the supplementary metals were not associated with the heat stable compounds including MTLP. At this site, hepatic MTLP bound more metals than at the unpolluted site, but its binding capacity was not sufficient to avoid the binding of metals to the insoluble and the heat denaturable fractions. In light of these results and in spite of its hermaphrodism, it is questionable whether to consider S. scriba as a good candidate for biomonitoring based on MTLP. S. porcus could be useful for this purpose only if the MTLP capacity in binding metals is not exceeded. The MTLP could be considered as a biomarker only if it is investigated in relatively unpolluted sites.
这项工作的目的是评估与鱼类性别状态相关的类金属硫蛋白（MTLP）水平自然波动相对于金属暴露引起的波动的相对重要性。为了观察金属暴露引起的波动，对在污染和未污染地点采样的同一种鱼类——黑鲪进行了比较。在未污染地点，对雌雄同体的鱼类——条纹锯鮨和黑鲪（其性别是分开的）进行了比较，以观察性别状态引起的波动。在这两个物种中，均测定了鳃和肝脏中的金属及MTLP水平。在这些器官中，研究了镉、铜和锌在不同组分中的分布：不溶性组分（IF）以及分为热不稳定化合物（HDF）和包括MTLP在内的热稳定化合物的细胞溶质。MTLP水平在肝脏中更高（黑鲪中为3.09毫克/克，条纹锯鮨中为1.59毫克/克），而在鳃中较低（黑鲪中为0.13毫克/克，条纹锯鮨中为0.40毫克/克）。对于黑鲪，金属和MTLP水平随性别而变化，而在雌雄同体的条纹锯鮨中，也观察到了内在变化。在污染地点，黑鲪鳃中的MTLP、镉和铜浓度增加，但额外的金属与包括MTLP在内的热稳定化合物无关。在该地点，肝脏MTLP结合的金属比未污染地点更多，但其结合能力不足以避免金属与不溶性和热变性组分结合。鉴于这些结果，尽管条纹锯鮨是雌雄同体，但基于MTLP将其视为生物监测的良好候选物种是否合理仍值得怀疑。只有当MTLP结合金属的能力未被超过时，黑鲪才可能适用于此目的。只有在相对未污染的地点进行研究时，MTLP才可以被视为生物标志物。
