The pepsin and trypsin activities and some of the properties of the two enzymes of southern sheatfish larvae were studied. The results were as follows: the highest level of trypsin activity is in the foregut in all...The pepsin and trypsin activities and some of the properties of the two enzymes of southern sheatfish larvae were studied. The results were as follows: the highest level of trypsin activity is in the foregut in all measured tissues; from foregut to hindgut, trypsin activities decrease; the pH optimum of trypsin activity is pH9.0; the strongest pepsin activity is in the stomach; the proper density of haemoglobin for detecting pepsin activity is 1.0%. These data are useful in solving applied nutritional problems, such as the adequacy of artificial food to the digestive abilities of the fish.展开更多
The separation and purification method for pepsin of Northern Sheatfish (Silurus soldatovi) was established by using the combination technology of salting-out,gel chromatography and gel electrophoresis,and the enzymic...The separation and purification method for pepsin of Northern Sheatfish (Silurus soldatovi) was established by using the combination technology of salting-out,gel chromatography and gel electrophoresis,and the enzymic properties were also analyzed.The experimental results indicated that 28% and 56% (NH4)2SO4 saturation could separate the activated protease from the pepsin extract of gastric mucosa of Sheatfish (Silurus soldatovi) ;compared with the homogenate extraction,the pepsin specific activity of purified extraction by Sephadex G-75 gel chromatography system increased 598 fold,was 5 times higher than that of activated liquid,and the total production rate was 10.1%.The purified pepsin liquor at the conditions of pH3.3 0.01 M alanine-formic acid buffering solution,60 cm chromatography column,and the flowing rate of 0.8 ML/min was analyzed by SDS-PAGE,which indicated that there were two bands and the molecular weight was 34.0 kDa and 40.4 kDa,respectively.There were two peaks in the enzyme activity determination of the separated collecting liquor in gel chromatography,and the SDS-PAGE showed the concentrations of the two proteins was different,which indicated that it existed at least two pepsins in the gastric mucosa of Sheatfish (Silurus soldatovi).展开更多
The surface ultrastructure of mature egg chorion of the tamed northern sheatfish Silurus soldatovi in Heilongjiang river was investigated by scanning electron microscopy. The outermost layer was composed of a thin lam...The surface ultrastructure of mature egg chorion of the tamed northern sheatfish Silurus soldatovi in Heilongjiang river was investigated by scanning electron microscopy. The outermost layer was composed of a thin lamella of a jelly coat. The surface of jelly coat was characterized by overlapping net-like fibrillar lamellae, many clefts with bridges and pores. The pore canals were 0.25 μm in diameter. The pore density was about 0.7-1.0/μm-2. The pores on the surface of jelly coart were distributed uniformly. Mature eggs of sheatfish possessed a funnel-shaped micropyle in the animal polar region. The micropylar region was about 0.04 mm2 area in diameter with 3-8 ridges in radial arrangement. Fertilized eggs in which jelly coats were removed mechanically presented no adhesiveness and exhibited inlays of irregular granules on their surface.展开更多
文摘The pepsin and trypsin activities and some of the properties of the two enzymes of southern sheatfish larvae were studied. The results were as follows: the highest level of trypsin activity is in the foregut in all measured tissues; from foregut to hindgut, trypsin activities decrease; the pH optimum of trypsin activity is pH9.0; the strongest pepsin activity is in the stomach; the proper density of haemoglobin for detecting pepsin activity is 1.0%. These data are useful in solving applied nutritional problems, such as the adequacy of artificial food to the digestive abilities of the fish.
基金Sponsored by the Key Research Program of Chinese Academy of Fishery Sciences (Grant No. 1999-01-10)Agricultural Science and Technology Fund of Department of Science and Technology (Grant No. 02EFN216900727)the National Natural Science Foundation of China (Grant No. 50638020)
文摘The separation and purification method for pepsin of Northern Sheatfish (Silurus soldatovi) was established by using the combination technology of salting-out,gel chromatography and gel electrophoresis,and the enzymic properties were also analyzed.The experimental results indicated that 28% and 56% (NH4)2SO4 saturation could separate the activated protease from the pepsin extract of gastric mucosa of Sheatfish (Silurus soldatovi) ;compared with the homogenate extraction,the pepsin specific activity of purified extraction by Sephadex G-75 gel chromatography system increased 598 fold,was 5 times higher than that of activated liquid,and the total production rate was 10.1%.The purified pepsin liquor at the conditions of pH3.3 0.01 M alanine-formic acid buffering solution,60 cm chromatography column,and the flowing rate of 0.8 ML/min was analyzed by SDS-PAGE,which indicated that there were two bands and the molecular weight was 34.0 kDa and 40.4 kDa,respectively.There were two peaks in the enzyme activity determination of the separated collecting liquor in gel chromatography,and the SDS-PAGE showed the concentrations of the two proteins was different,which indicated that it existed at least two pepsins in the gastric mucosa of Sheatfish (Silurus soldatovi).
文摘The surface ultrastructure of mature egg chorion of the tamed northern sheatfish Silurus soldatovi in Heilongjiang river was investigated by scanning electron microscopy. The outermost layer was composed of a thin lamella of a jelly coat. The surface of jelly coat was characterized by overlapping net-like fibrillar lamellae, many clefts with bridges and pores. The pore canals were 0.25 μm in diameter. The pore density was about 0.7-1.0/μm-2. The pores on the surface of jelly coart were distributed uniformly. Mature eggs of sheatfish possessed a funnel-shaped micropyle in the animal polar region. The micropylar region was about 0.04 mm2 area in diameter with 3-8 ridges in radial arrangement. Fertilized eggs in which jelly coats were removed mechanically presented no adhesiveness and exhibited inlays of irregular granules on their surface.
