The digestive tract of Takifugu rubripes during early life stages was studied with light microscopy. At the beginning of hatching, the digestive tract is represented by a simple and undifferentiated straight tube and ...The digestive tract of Takifugu rubripes during early life stages was studied with light microscopy. At the beginning of hatching, the digestive tract is represented by a simple and undifferentiated straight tube and does not communicate with the exterior, as the mouth and anus are not open yet. At 2 d after hatching, a constriction between intestine and rectum that will become the intestino-rectal valve is visible. During the endogenous feeding phase, the yolk sac is resorbed and the digestive tract becomes functional and differentiated. The liver and pancreas also become apparent at this time. At onset of exogenous feeding （3 d after hatching）, yolk sac resesves are not completely depleted, suggesting a period of mixed nutrition. The digestive tract differentiates fully into b.uccopharynx, esophagus, stomach, intestine and rectum. At 9 d after hatching, the yolk sac reserves are completely depleted. The most noticeable events occurring from 5 to 17 d after hatching are the transformation of the epithelia type, the differentiation of the pneumatic sac, the epithelial cell, gut convolution, mucosal fold increase, and the growth of liver and pancreas. From 18 to 27 d after hatching, the numbers of intestine folds and mucus cells increase progressively. From then on, morphological changes of digestive features are almost completed. At 27 d after hatching, the morphology and function of digestive system are similar to that of the adult.展开更多
The activities of some digestive enzymes are studied for Takifugu rubripes larvae and juvenile from the first feeding to 27 d after hatching at selected stages of development. The homogenate of whole larvae body is us...The activities of some digestive enzymes are studied for Takifugu rubripes larvae and juvenile from the first feeding to 27 d after hatching at selected stages of development. The homogenate of whole larvae body is used for enzymatic determination. Activity of acid protease decreases notably during the beginning days after the commencement of completely exogenous feeding and the days before the beginning of the juvenile stage. Alkaline protease specific activity also decreases at metamorphosis. The activities are associated with the morphology of the developing digestive tract. Amylase activity increases before the first feeding, followed by a decreasing and then a rather constant level. Lipase activity remains low during the larvae and juvenile periods. Alkaline phosphatase activity increases gradually. This reflects the development of brush border membranes of enterocytes.展开更多
The aim of the present study was to investigate the long-term effects of 17l）-estradiol （E2） exposure on gonadal development in the tiger puffer （Taktfugu rubripes）, which has a genetic sex determination system o...The aim of the present study was to investigate the long-term effects of 17l）-estradiol （E2） exposure on gonadal development in the tiger puffer （Taktfugu rubripes）, which has a genetic sex determination system of male homogametic XY-XX. Tiger puffer larvae were exposed to 1, 10 and 100 μg/L E2 from 15 to 100 days post-hatch （dph） and then maintained in clean seawater until 400 dph. Changes in sex ratio, gonadal structure and gonadosomatic index （GSI） were monitored at 100, 160, 270 and 400 dph. Sex-associated single nucleotide polymorphism （SNP） markers were used to analyze the genetic sex of samples, except those at 100 dph. Exposure had a positive effect on the conversion of genetically male gonads into phenotypically female gonads at 100 dph. However, gonads from 60% of genetic XY males in the 1-μg/L E2 group and 100% in the 10-μg/L E2 group developed intersexual gonads at 160 dph; gonads of all genetic XY males in the two treatment groups reverted to testis by 270 dph. While 38%, 57% and 44% of gonads of XY fish in the 100-gg/L E2 group reverted to intersexual gonads at 160, 270 and 400 dph, respectively, none reverted to testis after E2 treatment. In addition, E2 exposure inhibited gonadal growth of both genetic sexes, as indicated by the clear dose-dependent decrease in GSI at 270 and 400 dph. The results showed that exposure to E2 during the early life stages of tiger puffer disrupted gonadal development, but that fish recovered after migration to clean seawater. The study suggests the potential use of tiger puffer as a valuable indicator species to evaluate the effects of environmental estrogens on marine fish, thereby protecting valuable fishery resources.展开更多
The aim of the study was to examine the bacterial community associated with the intestinal mucus of young farmed puffer fish Takifugu rubripes. Polymerase chain reaction and partial 16 S r DNA sequencing was performed...The aim of the study was to examine the bacterial community associated with the intestinal mucus of young farmed puffer fish Takifugu rubripes. Polymerase chain reaction and partial 16 S r DNA sequencing was performed on DNA from bacteria cultivated on Zobell 2216 E medium. All the isolates were classified into two phyla—Proteobacteria and Firmicutes. Proteobacteria were the dominant, culturable intestinal microbiota(68.3%). At the genus level, V ibrio, Enterobacter, Bacillus, Pseudomonas, Exiguobacterium, Staphylococcus, Acinetobacter, Pseudoalteromonas and S hewanella were isolated from the intestine, with representatives of the genera V ibrio, Enterobacter and Bacillus accounting for 70.7% of the total. This is the first report of Enterobacter, Bacillus, Exiguobacterium and Staphylococcus as part of the intestinal bacterial microflora in T. rubripes. The profile of the culturable bacterial community differed between samples collected from the same tank at 2-month intervals, as indicated by Bray-Curtis and Sorensen indices, and the impact on the intestinal physiology and health of puffer fish requires further investigation.展开更多
Gasdermins(GSDMs)are proteins cleaved by caspase(CASP)to trigger pyroptosis.In teleosts,pyroptosis is mediated by gasdermin E(GSDME).The Pufferfish,Takifugu rubripes,possesses two GSDME orthologs:named TrGSDMEa and Tr...Gasdermins(GSDMs)are proteins cleaved by caspase(CASP)to trigger pyroptosis.In teleosts,pyroptosis is mediated by gasdermin E(GSDME).The Pufferfish,Takifugu rubripes,possesses two GSDME orthologs:named TrGSDMEa and TrGSDMEb.TrGSDMEa is cleaved by CASP3/7 to liberate the N-terminal(NT)domain that can trigger pyroptosis in mammalian cells.However,the biological function of TrGSDMEa in pufferfish is unknown,and TrGSDMEb is poorly studied.We found that TrGSDMEb was cleaved by CASP1/3/6/7/8,but the resulting NT domain,despite its similarity to TrGSDMEa-NT domain in sequence and structure,failed to induce pyroptosis.TrGSDMEa and TrGSDMEb exhibited similar expression patterns in pufferfish under normal physiological conditions but were up-and downregulated,respectively,in expression during Vibrio harveyi and Edwardsiella tarda infection.Bacterial infection induced the activation of TrGSDMEa and CASP3/7 in pufferfish cells,resulting in pyroptosis accompanied with IL-1βproduction and maturation.Inhibition of TrGSDMEa-mediated pyroptosis via TrCASP3/7 reduced the death of pufferfish cells and augmented bacterial dissemination in fish tissues.Structure-oriented mutagenesis identified 16 conserved residues in teleost GSDMEa that were required for the pore formation or auto-inhibition of GSDMEa.This study illustrates the role of GSDMEa-mediated pyroptosis in teleost defense against bacterial pathogens and provides new insights into the structure-based function of vertebrate GSDME.展开更多
文摘The digestive tract of Takifugu rubripes during early life stages was studied with light microscopy. At the beginning of hatching, the digestive tract is represented by a simple and undifferentiated straight tube and does not communicate with the exterior, as the mouth and anus are not open yet. At 2 d after hatching, a constriction between intestine and rectum that will become the intestino-rectal valve is visible. During the endogenous feeding phase, the yolk sac is resorbed and the digestive tract becomes functional and differentiated. The liver and pancreas also become apparent at this time. At onset of exogenous feeding （3 d after hatching）, yolk sac resesves are not completely depleted, suggesting a period of mixed nutrition. The digestive tract differentiates fully into b.uccopharynx, esophagus, stomach, intestine and rectum. At 9 d after hatching, the yolk sac reserves are completely depleted. The most noticeable events occurring from 5 to 17 d after hatching are the transformation of the epithelia type, the differentiation of the pneumatic sac, the epithelial cell, gut convolution, mucosal fold increase, and the growth of liver and pancreas. From 18 to 27 d after hatching, the numbers of intestine folds and mucus cells increase progressively. From then on, morphological changes of digestive features are almost completed. At 27 d after hatching, the morphology and function of digestive system are similar to that of the adult.
基金The present research is supported by the‘948’Of-fice Project of Ministry of Agriculture(963087)
文摘The activities of some digestive enzymes are studied for Takifugu rubripes larvae and juvenile from the first feeding to 27 d after hatching at selected stages of development. The homogenate of whole larvae body is used for enzymatic determination. Activity of acid protease decreases notably during the beginning days after the commencement of completely exogenous feeding and the days before the beginning of the juvenile stage. Alkaline protease specific activity also decreases at metamorphosis. The activities are associated with the morphology of the developing digestive tract. Amylase activity increases before the first feeding, followed by a decreasing and then a rather constant level. Lipase activity remains low during the larvae and juvenile periods. Alkaline phosphatase activity increases gradually. This reflects the development of brush border membranes of enterocytes.
基金Supported by the China Agriculture Research System(No.CARS-50-G20)the National Natural Science Foundation of China(No.31402284)the National High Technology Research and Development Program of China(863 Program)(No.2012AA10A413-2)
文摘The aim of the present study was to investigate the long-term effects of 17l）-estradiol （E2） exposure on gonadal development in the tiger puffer （Taktfugu rubripes）, which has a genetic sex determination system of male homogametic XY-XX. Tiger puffer larvae were exposed to 1, 10 and 100 μg/L E2 from 15 to 100 days post-hatch （dph） and then maintained in clean seawater until 400 dph. Changes in sex ratio, gonadal structure and gonadosomatic index （GSI） were monitored at 100, 160, 270 and 400 dph. Sex-associated single nucleotide polymorphism （SNP） markers were used to analyze the genetic sex of samples, except those at 100 dph. Exposure had a positive effect on the conversion of genetically male gonads into phenotypically female gonads at 100 dph. However, gonads from 60% of genetic XY males in the 1-μg/L E2 group and 100% in the 10-μg/L E2 group developed intersexual gonads at 160 dph; gonads of all genetic XY males in the two treatment groups reverted to testis by 270 dph. While 38%, 57% and 44% of gonads of XY fish in the 100-gg/L E2 group reverted to intersexual gonads at 160, 270 and 400 dph, respectively, none reverted to testis after E2 treatment. In addition, E2 exposure inhibited gonadal growth of both genetic sexes, as indicated by the clear dose-dependent decrease in GSI at 270 and 400 dph. The results showed that exposure to E2 during the early life stages of tiger puffer disrupted gonadal development, but that fish recovered after migration to clean seawater. The study suggests the potential use of tiger puffer as a valuable indicator species to evaluate the effects of environmental estrogens on marine fish, thereby protecting valuable fishery resources.
基金Supported by the Public Science and Technology Research Funds Projects of Ocean(No.201205025)
文摘The aim of the study was to examine the bacterial community associated with the intestinal mucus of young farmed puffer fish Takifugu rubripes. Polymerase chain reaction and partial 16 S r DNA sequencing was performed on DNA from bacteria cultivated on Zobell 2216 E medium. All the isolates were classified into two phyla—Proteobacteria and Firmicutes. Proteobacteria were the dominant, culturable intestinal microbiota(68.3%). At the genus level, V ibrio, Enterobacter, Bacillus, Pseudomonas, Exiguobacterium, Staphylococcus, Acinetobacter, Pseudoalteromonas and S hewanella were isolated from the intestine, with representatives of the genera V ibrio, Enterobacter and Bacillus accounting for 70.7% of the total. This is the first report of Enterobacter, Bacillus, Exiguobacterium and Staphylococcus as part of the intestinal bacterial microflora in T. rubripes. The profile of the culturable bacterial community differed between samples collected from the same tank at 2-month intervals, as indicated by Bray-Curtis and Sorensen indices, and the impact on the intestinal physiology and health of puffer fish requires further investigation.
基金supported by the Science&Tech-nology Innovation Project of Laoshan Laboratory(LSKJ202203000)the Postdoctoral Fellowship Program of CPSF(GZC20232709)the China Postdoctoral Science Foundation(2023TQ0356).
文摘Gasdermins(GSDMs)are proteins cleaved by caspase(CASP)to trigger pyroptosis.In teleosts,pyroptosis is mediated by gasdermin E(GSDME).The Pufferfish,Takifugu rubripes,possesses two GSDME orthologs:named TrGSDMEa and TrGSDMEb.TrGSDMEa is cleaved by CASP3/7 to liberate the N-terminal(NT)domain that can trigger pyroptosis in mammalian cells.However,the biological function of TrGSDMEa in pufferfish is unknown,and TrGSDMEb is poorly studied.We found that TrGSDMEb was cleaved by CASP1/3/6/7/8,but the resulting NT domain,despite its similarity to TrGSDMEa-NT domain in sequence and structure,failed to induce pyroptosis.TrGSDMEa and TrGSDMEb exhibited similar expression patterns in pufferfish under normal physiological conditions but were up-and downregulated,respectively,in expression during Vibrio harveyi and Edwardsiella tarda infection.Bacterial infection induced the activation of TrGSDMEa and CASP3/7 in pufferfish cells,resulting in pyroptosis accompanied with IL-1βproduction and maturation.Inhibition of TrGSDMEa-mediated pyroptosis via TrCASP3/7 reduced the death of pufferfish cells and augmented bacterial dissemination in fish tissues.Structure-oriented mutagenesis identified 16 conserved residues in teleost GSDMEa that were required for the pore formation or auto-inhibition of GSDMEa.This study illustrates the role of GSDMEa-mediated pyroptosis in teleost defense against bacterial pathogens and provides new insights into the structure-based function of vertebrate GSDME.
