The genetic diversity and differentiation of 6 mud crab Scylla serrata populations from southeastern China are investigated using allozyme electrophoresis. The mean number of alleles per locus population is 1.3 ±...The genetic diversity and differentiation of 6 mud crab Scylla serrata populations from southeastern China are investigated using allozyme electrophoresis. The mean number of alleles per locus population is 1.3 ± 0.1; the percentage of polymorphic loci per population is 27.3; the observed heterozygosity ranges from (0.195±0.083) to ( 0.241±0.090) and the expected heterozygosity ranges from ( 0.105±0.043 ) to ( 0.131±0.047 ). The coefficient of gene differentiation among populations is low (Fst =0.032), indicating that only 3.2 % of the total genetic diversity comes from inter-population, while the remaining 96.8 % comes from intra-population differences. The genetic distance among populations is 0.000-0.008 (the average is 0.002). Gene flow among the populations is large (Nm = 7.56).Genetic structure is very similar among 6 Scylla serrata populations.展开更多
The reproductive endocrine activities of neuroendocrine organs and androgenic glands (AG) in male Scylla serrata were investigated with co-incubation technology. In vitro studies show that: (1) the AG in Stage Ⅲ can ...The reproductive endocrine activities of neuroendocrine organs and androgenic glands (AG) in male Scylla serrata were investigated with co-incubation technology. In vitro studies show that: (1) the AG in Stage Ⅲ can significantly accelerate the development of seminiferous tubules and spermic matu- ration; (2) the brain, thoracic ganglia and optic ganglia have no direct influence over the testicular devel- opment; (3) the brain and thoracic ganglia can significantly promote the growth of the AG cells and highly significantly boost the ratio of Type B cells, while the optic ganglia have no such effects. It is the first time for in vitro investigations to confirm that the brain and thoracic ganglia can regulate testicular development through AG in male crustaceans.展开更多
The regulation of three biogenic amines over the reproductive neuroendoerine activity of the male Scylla serrata was investigated by in vivo injection and in vitro incubation. The testicular index, the ratio of the ma...The regulation of three biogenic amines over the reproductive neuroendoerine activity of the male Scylla serrata was investigated by in vivo injection and in vitro incubation. The testicular index, the ratio of the mature sections in testes, and the ratio of Type B cells in androgenic gland were taken as the quantitative indexes. The in vivo injections indicated that： 5-HT can significantly promote the testicular development and the secretion of the androgenic gland in S. serrata; DA can inhibit the testicular development, but no influence on the secretion of the androgenic gland was found; no significant difference was observed between the OA-injected group and the concurrent control group. In vitro incubations showed that： 5-HT can stimulate the secretion of the brain and the thoracic ganglia, thus accelerating that of the androgenic gland; however, neither OA nor DA showed any significant influence on the secretion of the brain and the thoracic ganglionic mass. As to the optic ganglia, the three biogenic amines hardly have any effect on its secretion. It is the first time to report the regulation of biogenic amines over the reproductive neuroendocrine of male crustaceans through vitro experiments. Results corroborate that 5-HT activates the brain and the thoracic ganglia to secret GSH first, then promote the testicular development through the activity of the androgenic gland.展开更多
N-Acetyl-β-D-glucosaminidase（NAGase, EC 3.2.1.52）, which catalyzes the cleavage of N-acetylgluco- samine polymers, plays important roles in the molting, digestion of chitinous foods in green crab. In the study, the...N-Acetyl-β-D-glucosaminidase（NAGase, EC 3.2.1.52）, which catalyzes the cleavage of N-acetylgluco- samine polymers, plays important roles in the molting, digestion of chitinous foods in green crab. In the study, the efforts of urea on the activity of NAGase purified from the viscera of green crab（Scylla serrata） have been studied. The results show that appropriate concentrations of urea can lead to reversible inactivation of the enzyme, and the value of the inhibitor concentration leading to 50% of enzyme activity lost（IC50） is estimated to be 0.63 mol/L. The inactivation kinetics has been studied via the kinetic method of the substrate reaction. The rate constants of inactivation have been determined. The value of k＋0 is larger than that of k′＋0, indicating the free enzyme molecule is more fragile than the enzyme-substrate complex in urea solution. It is suggested that the presence of the substrate offers the marked protection of this enzyme against inactivation by urea.展开更多
Mud crab （Scylla serrata） is an important commercial crustacean in China. An experiment was designed to study the effect of cold stress on S. serrata. After a one-week adaptation at 28℃, the temperature is suddenly...Mud crab （Scylla serrata） is an important commercial crustacean in China. An experiment was designed to study the effect of cold stress on S. serrata. After a one-week adaptation at 28℃, the temperature is suddenly reduced to 4℃. The crabs were sampled every 2 h for 10 h and dissected immediately to measure the enzyme activity. The crabs at room temperature （28℃） were used as the control group. The activity of superoxide dismutase （SOD）, catalase （CAT） and gkttathione peroxidase （GPX）, the content of malondialdehyde （MDA） and the activity of 4 ATPases （Na^＋, K^＋-ATPase, Mg^2＋-ATPase; Ca^2＋-ATPase; Ca^2＋, Mg^2＋-ATPase） were measured biochemically. In contrast to the control group, the SOD activity increased significantly from 2 to 6 h after the cold stress, and then decreased. The CAT and GPX activities increased in 2 h, and then decreased gradually. The content of MDA increased gradually in 4 h. The activity of Na^＋, K^＋-ATPase decreased in 2 h, increased up to the top value at Hour 6, then decreased again. The activities of Mg^2＋-ATPase, Ca^2＋-ATPase and Ca^2＋, Mg^2＋-ATPase increased significantly in 6 h, insignificantly in any other hours. Under cold stress, the activity of antioxidative enzymes in S, serrata was reduced at first then stabilized, ROS-scavenging weakened, and MDA accumulated gradually in the gill after 6 h. The activity of the 4 ATPases in the crab decreased after 6 h, suggesting that the ability to regulate ion concentration has been paralyzed. Therefore, the maximum period to sustain healthy meat in the crab under cold stress is 6 hours.展开更多
Acute-phase response is documented to be a significant mechanism of innate immunity in vertebrates and invertebrates.In this study,proteomic methodologies were applied for different protein expressions in hemolymph of...Acute-phase response is documented to be a significant mechanism of innate immunity in vertebrates and invertebrates.In this study,proteomic methodologies were applied for different protein expressions in hemolymph of Scylla serrata challenged by Vibrio parahaemolyticus after immunization,and in muscles of the crabs separately chal-lenged by V.parahaemolyticus,V.anguillarum and Aeromonas hydrophila.Up-regulated cryptocyanin is documented in the hemolymph and up-regulated calexcitin,wingless(fragment)and tachykinin-related peptide in the muscle as acute-phase proteins.All the four altered proteins were responsible for bacterial stress,but cryptocyanin seemed to be a memory response protein against the chal-lenge by a live bacterium after immunization of the live cells.These up-regulated proteins can be indicative of an understanding of immunity of a crab.展开更多
A value chain analysis is a detailed description of all the activities and services needed to turn a raw product into a marketable good for delivery to final consumers.The mud crab business is considered by most marke...A value chain analysis is a detailed description of all the activities and services needed to turn a raw product into a marketable good for delivery to final consumers.The mud crab business is considered by most marketing operators to be a profitable and viable business due to the high demand in the international market.Despite the importance of mud crab fishery,there is no structured marketing facilities in Bangladesh.This research aim to analyze the socioeconomic condition of actors,the profitability of farming,mapping the institutional and non-institutional barriers,and provide a better understanding of the possibility of technological interventions in the value chain.Qualitative and quantitative data were collected through participatory rural appraisal tools that include 200 individual interviews,16 focus group discussions,and 24 key informant interviews conducted in south-west Bangladesh from July to December of 2019.The mud crab value chain analysis revealed that the chain started with crab collection(cultivated and wild harvest),before sale to local vendors,and ended with exporters through several intermediaries.Results noted that most(±95%)exportable crab came from natural sources,with rest(±5%)from aquaculture sector.The average price(USD/kg)ranged from$10.5914.12 and$12.9419.42 for male crabs(grade:XXL),followed by$10.0011.77 and$11.7717.06 for female(grade:FF1)in domestic and international markets,respectively.Despite the high profitability of these sectors,the livelihood of these stakeholders has remained relatively hard.Multi-pronged approaches,like a nursery or increasing farming and backyard seed production,and possible value addition at the farm level may help farmers.展开更多
基金This study was supported by the National Natural Science Foundation of China under contract No.40376044Marine“863"Item of China under contract No.2002AA603013Foundation of Jimei University.
文摘The genetic diversity and differentiation of 6 mud crab Scylla serrata populations from southeastern China are investigated using allozyme electrophoresis. The mean number of alleles per locus population is 1.3 ± 0.1; the percentage of polymorphic loci per population is 27.3; the observed heterozygosity ranges from (0.195±0.083) to ( 0.241±0.090) and the expected heterozygosity ranges from ( 0.105±0.043 ) to ( 0.131±0.047 ). The coefficient of gene differentiation among populations is low (Fst =0.032), indicating that only 3.2 % of the total genetic diversity comes from inter-population, while the remaining 96.8 % comes from intra-population differences. The genetic distance among populations is 0.000-0.008 (the average is 0.002). Gene flow among the populations is large (Nm = 7.56).Genetic structure is very similar among 6 Scylla serrata populations.
基金This work was supported by the National Natural Science Foundation of China (No.30300269) and the Fujian Province Key Foundation Re-search Program (1998-2002).
文摘The reproductive endocrine activities of neuroendocrine organs and androgenic glands (AG) in male Scylla serrata were investigated with co-incubation technology. In vitro studies show that: (1) the AG in Stage Ⅲ can significantly accelerate the development of seminiferous tubules and spermic matu- ration; (2) the brain, thoracic ganglia and optic ganglia have no direct influence over the testicular devel- opment; (3) the brain and thoracic ganglia can significantly promote the growth of the AG cells and highly significantly boost the ratio of Type B cells, while the optic ganglia have no such effects. It is the first time for in vitro investigations to confirm that the brain and thoracic ganglia can regulate testicular development through AG in male crustaceans.
基金supported by the National Natural Science Foundation of China under contract No.30300269the National High Technology Research and Development Program("863"program)of China under contract No.2002AA603013.
文摘The regulation of three biogenic amines over the reproductive neuroendoerine activity of the male Scylla serrata was investigated by in vivo injection and in vitro incubation. The testicular index, the ratio of the mature sections in testes, and the ratio of Type B cells in androgenic gland were taken as the quantitative indexes. The in vivo injections indicated that： 5-HT can significantly promote the testicular development and the secretion of the androgenic gland in S. serrata; DA can inhibit the testicular development, but no influence on the secretion of the androgenic gland was found; no significant difference was observed between the OA-injected group and the concurrent control group. In vitro incubations showed that： 5-HT can stimulate the secretion of the brain and the thoracic ganglia, thus accelerating that of the androgenic gland; however, neither OA nor DA showed any significant influence on the secretion of the brain and the thoracic ganglionic mass. As to the optic ganglia, the three biogenic amines hardly have any effect on its secretion. It is the first time to report the regulation of biogenic amines over the reproductive neuroendocrine of male crustaceans through vitro experiments. Results corroborate that 5-HT activates the brain and the thoracic ganglia to secret GSH first, then promote the testicular development through the activity of the androgenic gland.
基金Supported by the National Natural Science Foundation of China(No.40576066)the Science and Technology Foundation of Xiamen,China(No.3502Z20081143)
文摘N-Acetyl-β-D-glucosaminidase（NAGase, EC 3.2.1.52）, which catalyzes the cleavage of N-acetylgluco- samine polymers, plays important roles in the molting, digestion of chitinous foods in green crab. In the study, the efforts of urea on the activity of NAGase purified from the viscera of green crab（Scylla serrata） have been studied. The results show that appropriate concentrations of urea can lead to reversible inactivation of the enzyme, and the value of the inhibitor concentration leading to 50% of enzyme activity lost（IC50） is estimated to be 0.63 mol/L. The inactivation kinetics has been studied via the kinetic method of the substrate reaction. The rate constants of inactivation have been determined. The value of k＋0 is larger than that of k′＋0, indicating the free enzyme molecule is more fragile than the enzyme-substrate complex in urea solution. It is suggested that the presence of the substrate offers the marked protection of this enzyme against inactivation by urea.
基金the National High-Tech Research and Development Program of China (863 Program) (No. 2002AA603013)
文摘Mud crab （Scylla serrata） is an important commercial crustacean in China. An experiment was designed to study the effect of cold stress on S. serrata. After a one-week adaptation at 28℃, the temperature is suddenly reduced to 4℃. The crabs were sampled every 2 h for 10 h and dissected immediately to measure the enzyme activity. The crabs at room temperature （28℃） were used as the control group. The activity of superoxide dismutase （SOD）, catalase （CAT） and gkttathione peroxidase （GPX）, the content of malondialdehyde （MDA） and the activity of 4 ATPases （Na^＋, K^＋-ATPase, Mg^2＋-ATPase; Ca^2＋-ATPase; Ca^2＋, Mg^2＋-ATPase） were measured biochemically. In contrast to the control group, the SOD activity increased significantly from 2 to 6 h after the cold stress, and then decreased. The CAT and GPX activities increased in 2 h, and then decreased gradually. The content of MDA increased gradually in 4 h. The activity of Na^＋, K^＋-ATPase decreased in 2 h, increased up to the top value at Hour 6, then decreased again. The activities of Mg^2＋-ATPase, Ca^2＋-ATPase and Ca^2＋, Mg^2＋-ATPase increased significantly in 6 h, insignificantly in any other hours. Under cold stress, the activity of antioxidative enzymes in S, serrata was reduced at first then stabilized, ROS-scavenging weakened, and MDA accumulated gradually in the gill after 6 h. The activity of the 4 ATPases in the crab decreased after 6 h, suggesting that the ability to regulate ion concentration has been paralyzed. Therefore, the maximum period to sustain healthy meat in the crab under cold stress is 6 hours.
基金supported by Hi-Tech Research and Development Program of China (No.2002AA603013)the Natural Science Foundation of Fujian Province (No.B0110005).
文摘Acute-phase response is documented to be a significant mechanism of innate immunity in vertebrates and invertebrates.In this study,proteomic methodologies were applied for different protein expressions in hemolymph of Scylla serrata challenged by Vibrio parahaemolyticus after immunization,and in muscles of the crabs separately chal-lenged by V.parahaemolyticus,V.anguillarum and Aeromonas hydrophila.Up-regulated cryptocyanin is documented in the hemolymph and up-regulated calexcitin,wingless(fragment)and tachykinin-related peptide in the muscle as acute-phase proteins.All the four altered proteins were responsible for bacterial stress,but cryptocyanin seemed to be a memory response protein against the chal-lenge by a live bacterium after immunization of the live cells.These up-regulated proteins can be indicative of an understanding of immunity of a crab.
文摘A value chain analysis is a detailed description of all the activities and services needed to turn a raw product into a marketable good for delivery to final consumers.The mud crab business is considered by most marketing operators to be a profitable and viable business due to the high demand in the international market.Despite the importance of mud crab fishery,there is no structured marketing facilities in Bangladesh.This research aim to analyze the socioeconomic condition of actors,the profitability of farming,mapping the institutional and non-institutional barriers,and provide a better understanding of the possibility of technological interventions in the value chain.Qualitative and quantitative data were collected through participatory rural appraisal tools that include 200 individual interviews,16 focus group discussions,and 24 key informant interviews conducted in south-west Bangladesh from July to December of 2019.The mud crab value chain analysis revealed that the chain started with crab collection(cultivated and wild harvest),before sale to local vendors,and ended with exporters through several intermediaries.Results noted that most(±95%)exportable crab came from natural sources,with rest(±5%)from aquaculture sector.The average price(USD/kg)ranged from$10.5914.12 and$12.9419.42 for male crabs(grade:XXL),followed by$10.0011.77 and$11.7717.06 for female(grade:FF1)in domestic and international markets,respectively.Despite the high profitability of these sectors,the livelihood of these stakeholders has remained relatively hard.Multi-pronged approaches,like a nursery or increasing farming and backyard seed production,and possible value addition at the farm level may help farmers.
