The true freshwater crabs(Crustacea,Decapoda,Brachyura) are highly adapted to life in freshwater and complete their life cycle entirely independently of sea water.All true freshwater crabs exhibit direct development a...The true freshwater crabs(Crustacea,Decapoda,Brachyura) are highly adapted to life in freshwater and complete their life cycle entirely independently of sea water.All true freshwater crabs exhibit direct development and lack the free-living larval forms(zoea and megalopa) typical of most other brachyurans.After a prolonged embryonic period(during which they pass through the typical brachyuran larval forms embryologically) the eggs of true freshwater crabs hatch to produce juvenile(hatchling) crabs.We provide here the first report and description of the continuous record of embryonic development from egg-laying up to hatching in the Chinese true freshwater crab Sinopotamon yangtsekiense Bott,1967(Potamoidea,Potamidae).Direct development(complete secondary embryonization) in S.yangtsekiense was observed to take 77 days and to include an additional embryonic phase(termed here the egg-juvenile-crab) that occurs in the embryo between the imprisoned megalopa and the newly-emerged juvenile(hatchling) crab.This is significant because the only other freshwater crab whose embryonic development has been studied in detail is Potamon fluviatilis(Potamidae) which takes 45-47 days and involves only nine embryonic stages.展开更多
The toxicities of 4 common endocrine-disrupting chemicals （EDCs）, 17β-estradiol （E2）, p,p＇-dichlorodiphenyldi- chloro-ethylene （DDE）, 4-nonylphenol （NP） and tributyltin （TBT）, to sperm motility, fertilizat...The toxicities of 4 common endocrine-disrupting chemicals （EDCs）, 17β-estradiol （E2）, p,p＇-dichlorodiphenyldi- chloro-ethylene （DDE）, 4-nonylphenol （NP） and tributyltin （TBT）, to sperm motility, fertilization rate, hatching rate and embryonic development of Barbel chub （Squaliobarbus curriculus） were investigated in this study. The duration of sperm motility was signifi- cantly shortened by exposure to the EDCs at the threshold concentrations of 10ngL-1 for E2 and TBT, 1 μgL l for NP and 100 μgL-1 for DDE, respectively. The fertilization rate was substantially reduced by the EDCs at the lowest observable effect concentrations （LOECs） of 10 ngL-1 for E2 and TBT and 10μgL-1 for DDE and NP, respectively. Of the tested properties of S. curriculus, larval deformity rate was most sensitive to EDC exposure and was significantly increased by DDE at the lowest experimental level of 0.1 μgL-1. Other EDCs increased the larval deformity rate at the LOECs of 1 ngL-1 for E2, 10ngL-1 for TBT and 1μgL-1 for NP, re- spectively. Despite their decreases with the increasing EDC concentrations, the hatching rate and larval survival rate of S. curriculus were not significantly affected by the exposure to EDCs. The results indicated that all the 4 EDCs affected significantly and nega- tively the early life stages of the freshwater fish S. curriculus. Overall, E2 and TBT were more toxic than NP and DDE, while DDE might be more toxic to larval deformity rate than to other measured parameters. Thus, the 4 EDCs showed potential negative influ- ences on natural population dynamics of S. curriculus. Our findings provided valuable basic data for the ecological risk assessment of E2, DDE, NP and TBT.展开更多
基金Supported by the Shanghai Leading Academic Discipline Project(No.S30701)the Leading Academic Discipline Project of Shanghai Municipal Education Commission(No.J50701)
文摘The true freshwater crabs(Crustacea,Decapoda,Brachyura) are highly adapted to life in freshwater and complete their life cycle entirely independently of sea water.All true freshwater crabs exhibit direct development and lack the free-living larval forms(zoea and megalopa) typical of most other brachyurans.After a prolonged embryonic period(during which they pass through the typical brachyuran larval forms embryologically) the eggs of true freshwater crabs hatch to produce juvenile(hatchling) crabs.We provide here the first report and description of the continuous record of embryonic development from egg-laying up to hatching in the Chinese true freshwater crab Sinopotamon yangtsekiense Bott,1967(Potamoidea,Potamidae).Direct development(complete secondary embryonization) in S.yangtsekiense was observed to take 77 days and to include an additional embryonic phase(termed here the egg-juvenile-crab) that occurs in the embryo between the imprisoned megalopa and the newly-emerged juvenile(hatchling) crab.This is significant because the only other freshwater crab whose embryonic development has been studied in detail is Potamon fluviatilis(Potamidae) which takes 45-47 days and involves only nine embryonic stages.
基金supported by the National Science Foundation of China(No.40632009)
文摘The toxicities of 4 common endocrine-disrupting chemicals （EDCs）, 17β-estradiol （E2）, p,p＇-dichlorodiphenyldi- chloro-ethylene （DDE）, 4-nonylphenol （NP） and tributyltin （TBT）, to sperm motility, fertilization rate, hatching rate and embryonic development of Barbel chub （Squaliobarbus curriculus） were investigated in this study. The duration of sperm motility was signifi- cantly shortened by exposure to the EDCs at the threshold concentrations of 10ngL-1 for E2 and TBT, 1 μgL l for NP and 100 μgL-1 for DDE, respectively. The fertilization rate was substantially reduced by the EDCs at the lowest observable effect concentrations （LOECs） of 10 ngL-1 for E2 and TBT and 10μgL-1 for DDE and NP, respectively. Of the tested properties of S. curriculus, larval deformity rate was most sensitive to EDC exposure and was significantly increased by DDE at the lowest experimental level of 0.1 μgL-1. Other EDCs increased the larval deformity rate at the LOECs of 1 ngL-1 for E2, 10ngL-1 for TBT and 1μgL-1 for NP, re- spectively. Despite their decreases with the increasing EDC concentrations, the hatching rate and larval survival rate of S. curriculus were not significantly affected by the exposure to EDCs. The results indicated that all the 4 EDCs affected significantly and nega- tively the early life stages of the freshwater fish S. curriculus. Overall, E2 and TBT were more toxic than NP and DDE, while DDE might be more toxic to larval deformity rate than to other measured parameters. Thus, the 4 EDCs showed potential negative influ- ences on natural population dynamics of S. curriculus. Our findings provided valuable basic data for the ecological risk assessment of E2, DDE, NP and TBT.
