| The water quality of Dianchi Lake has dramatically changed since1970s. Cyanobacteria blooms frequently happen that leads to extinction of indigenous species such as Ottelia acuminate, Sinocyclocheilus graham and barrier to recovery. During it, allelopathy of cyanobacteria may play a significant role. S.grahami is a national second class protected animal (endangered level), which is surrogate species and indicator species of Lake Dian ecosystem. However, it has disappeared in the lake since1986, only few survived in small lakes around the Dianchi Lake. The artificial propagation of S. grahami successed and1million fish fries have been put back to Dianchi Lake. Fish fries cannot form natural populations even though they can survive. Allelopathy of cyanobacteria can be one of factors to restrict reintroduction of S.grahami. This research on the basis of excluding other interference factors and focuses on the allelopathy of S. grahami’s embryo affected by MaE and its molecular effects, by semi-continuous adding method. The results show:(1) Allelopathy of MaE had significant inhibition on sperm of S. grahami, and shows "dose-effect" relationship, sperm vitality duration of sperm movement and duration time in forward/curvilinear/tremble movement all reduced along with the concentration of MaE concentration increasing. The strongest inhibit effects of MaE shows in100%concentration (corresponding algal concentration is4*106cells/ml), sperm vitality inhibition rate is77.03%, and the key period of fertilization (sperm forward movement) inhibition rate was35.38%. The lowest embryo fertilization rate shows in100%concentration too, is35.40%,47.24%lower than control. (2) The embryonic development stage of S. grahami can be divided into cleavage period, blastula period, gastrula period, segmentation period and hatching period. MaE shows no significant effect (T test, P>0.05) on cleavage, gastrula and segmentation period, while blastula and hatching period are effected, with the concentration increasing the time of development duration time in blastula speed up compared with control, faster2.5h than control in100%concentration group.30%(corresponding to the algae concentration is1.2*106cells/ml) concentration group shows development retardation in hatching period while other treatment group shows development speed up in MaE exposure. In100%concentration treatment group, the hatching time is about12hours in advance.(3) The MaE shows strong inhibit effects on hatching rate, heart rate and survival rate and shows "dose-effect" relationship. The strongest inhibit effect shows in100%concentration, the hatching rate, heart rate and survival rate is15.48%,64.44%and90.67drops/min respectively, which decreased81.63%,33.34%and24.45%respectively compared with control. Expect length of yolk sac, the other signs of fries has no siginificant change in MaE exposure. Length of yolk sac has decreased20.13%Compare with control.(4) MaE shows strong teratogenic effect on embryo of S. grahami, the malformation rate of embryos are decreased after increase, the highest malformation rate shows in50%concentration, is39.28%,1.37folds higher than control.Although the teratogenic effect is one of the most important sublethal indicator to evaluate the toxicity of poisonous substance, there is no comprehensive quantitative evaluation index system. In this study, the embryonic malformation type is divided into five types (Level1):yolk sac malformations, thoracic deformity, spinal curvature, mult-malformation and other malformation type (i.e. Two-headed), except other malformation type, the other four types subdivided into three levels (Level2). MaE exposure, embryo yolk sac deformity rate decreases along with the MaE concentration increasing, and the lowest malformation rates shows in100%concentration group,83.19%lower than control. The highest thoracic deformity rates is23.03%shows in10%concentration treatment group,53.98%higher than control; The highest spinal curvature rate shows in30%concentration, is25.44%,97.67%higher than control. The highest rate of multi-malformation and other malformation type, which increasing along with MaE increasing, shows in50%concentration group, are51.85%(3.63folds higher than control) and4.46%(no this malformation type in control), respectively. The higher MaE concentration treats, the worse malformation that the embryo suffered in same malformation type but in different concentration. The reason of malformation rate of embryonic malformation, thoracic deformity and spinal curvature decreased in high concentration is the embryonic malformation which in high MaE concentration is characterized by mult-malformation, single malformation is more less.(5) MaE shows no significant lethal effect on the early development stage (cleavage stage and blastula stage) of S.grahami’s embryo (T test,P<0.05), the mortality rate of control and treatment group all under16%. From gastrulae stage, MaE shows significant lethal effect on embryos and shows "dose-effect" relationship, mortality rate is increasing along with the MaE concentration increasing. The highest mortality rates of gastrulae/segmentation/hatching period all shows in100%concentration, is54.60%,72.3%,83.30and88.33%, respectively. Except exposure MaE in100%concentration treatment shows siginificant lethal effect in72h, the MaE show no siginificant lethal effect in other treatment group until18d. After MaE exposure for24d, the highest mortality rate is83.33%, shows in100%concentraton treatment,3.72folds higher than control, this results suggests, the MaE may be have a cumulative effect, embryo is more sensitive than fry.(6) This study identified446proteins by labelfree protein analysis, there are148proteins shows significantly different (T test, P<0.05; ration≥2),80proteins only identified in control, while3proteins identified in treatment. By bioinformatics analysis Disorder of calcium ion, lipid metabolism disorder is the cause of larvae of heart development abnormal. |
PDF Full Text Request