Methylene blue(MB) is commonly used in aquaculture as a fungicide and antidotes. This study was designed to explore the pharmacokinetics of MB in Japanese eel(Anguilla Japonica) immersed in 10 mg L^-1 and 20 mg L^-1 M...Methylene blue(MB) is commonly used in aquaculture as a fungicide and antidotes. This study was designed to explore the pharmacokinetics of MB in Japanese eel(Anguilla Japonica) immersed in 10 mg L^-1 and 20 mg L^-1 MB for 0.5 h. The concentrations of MB and its derivatives in the blood, liver, kidney, skin and muscle were determined by HPLC after immersion. The results showed that the changes of drug concentrations in Japanese eel were basically the same in different dose groups, showing a general trend of increasing at first and then decreasing, but the peak time was slightly different. The peak concentration of the drug was positively correlated with the dose level. The peak concentrations of MB in MB(20 mg L^-1) group, MB, azure A and azure B in the tissues of Japanese eel were significantly higher than those in MB(10 mg L^-1) group. Moreover, MB, azure A and azure B remained for a long time and could still be detected at 64 days, and azure C was not detected in tissues.展开更多
The Japanese eel(Anguilla japonica)is a commercially important fi sh species in East Asia and its recruitment has been rapidly declining since 1990s.Clarifying the genetic population structure of A.japonica is the bas...The Japanese eel(Anguilla japonica)is a commercially important fi sh species in East Asia and its recruitment has been rapidly declining since 1990s.Clarifying the genetic population structure of A.japonica is the basis of multinational cooperation on its management and protection,due to its large distribution range.Gene-associated markers have been proved powerful in delineating fi ne-scale population genetic structure and spatially varying selection.In the present study,we developed 24 polymorphic gene-associated microsatellite markers including 18 loci associated with the genes under selection in the two North Atlantic eel species(Anguilla anguilla and Anguilla rostrata)and 6 loci based on transcript sequences.A total of 13 geographic populations were sampled across its distribution range,including 11 samples from China(9 from China’s mainland and 2 from Taiwan region),and 2 samples from Japan.A total of 416 individuals(mostly glass eels)were collected and genotyped at the 24 microsatellites.All measures of diff erentiation were accordant with a panmictic scenario(F ST=-0.001)in A.japonica.No footprints of spatially varying selection were found,indicating that the selection pattern in A.japonica might be diff erent from that in the two North Atlantic eel species.We suggest that A.japonica should be managed as a single unit and management and conservation eff orts must be coordinated at the international level,as overexploitation in any region will decrease its recruitment across the whole distributional range.展开更多
As a potent pleiotropic cytokine, tumor necrosis factor-alpha(TNF-α) plays an important role in innate immune responses. The cDNA sequence and genomic structure of the TNF-α gene( Aj TNF-α) in the Japanese eel( Ang...As a potent pleiotropic cytokine, tumor necrosis factor-alpha(TNF-α) plays an important role in innate immune responses. The cDNA sequence and genomic structure of the TNF-α gene( Aj TNF-α) in the Japanese eel( Anguilla japonica) were identified and characterized. The full-length Aj TNF-α cDNA was 1 546 bp, including a 5′-untranslated region(UTR) of 13 bp, a 3′-UTR of 879 bp and an open reading frame of 654 bp encoding a protein of 218 amino acids. The full-length genomic sequence of Aj TNF-α was 2 392 bp and included four exons and three introns. The putative Aj TNF-α protein contained TNF family signature motifs, including a protease cleavage site, a transmembrane domain and two conserved cysteine residues. Quantitative real-time reverse transcription PCR analysis revealed Aj TNF-α expression in a wide range of tissues, with predominant expression in blood and liver. Lower levels of expression were seen in spleen, gills, kidney, intestine, heart, and skin, with very low levels in muscle. The modulation of Aj TNF-α expression after injection of eels with lipopolysaccharide(LPS), the viral mimic, poly I:C, or Aeromonas hydrophila was assessed in blood, liver, and kidney. In blood, TNF-α mRNA levels increased rapidly and then rapidly decreased after stimulation with LPS, poly I:C or A. hydrophila. However, the response to LPS and A. hydrophila peaked at 6 h while for poly I:C the peak was at 12 h. In liver, after injection with A. hydrophila, an up- and down-regulation of Aj TNF-α expression occurred twice, peaking at 6 h and 24 h, respectively. No remarkable increase of Aj TNF-α expression appeared in liver until 72 h after LPS or poly I:C treatment. In kidney, Aj TNF-α expression increased significantly only at 72 h post-stimulation with LPS or A. hydrophila. Our results suggest that Aj TNF-α plays an important role in fish in the defense against viral and bacterial infection.展开更多
Major histocompatibility complex(MHC)molecules play a critical role in the immune response of vertebrate animals by presenting foreign antigens to T lymphocytes.In this study,we first cloned and identified a classical...Major histocompatibility complex(MHC)molecules play a critical role in the immune response of vertebrate animals by presenting foreign antigens to T lymphocytes.In this study,we first cloned and identified a classical and a novel nonclassical MHC Iαmolecules from Japanese eel(Anguilla japonica),named as AjMHC I-UBA and AjMHC I-L,respectively.The full-length cDNA of AjMHC I-UBA contains an open reading frame(ORF)of 1047 bp encoding a predicted protein of 348 amino acids,while AjMHC I-L 1089 bp encodes 362 amino acids.The multiple alignment of the amino acid sequence showed that AjMHC I-UBA and AjMHC I-L consist of an N-terminal MHC I superfamily domain withinα1 andα2 helices,an IgC-MHC Iα3 domain,and a transmembrane region close to the C-terminal,which are similar to other fish and mammal species.Molecular polymorphism analysis showed that eight different major alleles of AjMHC I-UBA,named as AjMHC I-UBA*0101~1001,were identified from six Japanese eel individuals.Furthermore,a distinguishing signature of the nonclassical L-lineage genes specific motif“HINMTL”,including an N-glycosylation site(NXS/T),was present in theα3 domain of AjMHC I-L sequences.Although the predicted three-dimensional structures of AjMHC I-UBA and AjMHC I-L are similar to that of human MHC Iα,phylogenetic analysis showed that these two protein molecules belong to classical MHC I UBA gene of U-lineage and nonclassical MHC I gene of L-lineage,respectively.Quantitative real-time polymerase chain reaction(qRT-PCR)analysis revealed that the highest expression of AjMHC I-UBA and AjMHC I-L was found in the intestine and the expression level of AjMHC I-UBA in all of the examined tissues was significantly higher than that of AjMHC I-L.The expressions of AjMHC I-UBA and AjMHC I-L in liver,kidney and spleen were significantly induced following injection with the viral mimic poly I:C,LPS,and Aeromonas hydrophila infection.In vitro,the AjMHC I-UBA and AjMHC I-L transcripts of Japanese eel liver cells were significantly enhanced by the treatment of poly I:C or the stimulation of the high concentration of A.hydrophila.Subcellular localization showed that under natural conditions,AjMHC I-UBA and AjMHC I-L were uniformly distributed in the cytoplasm,and aggregated into spots or flakes in the cytoplasm after the stimulation of poly I:C or LPS.These results collectively suggested that AjMHC I-UBA and AjMHC I-L are important components possibly involved in Japanese eel defense against viral and bacterial infection.Taken together,these findings provide valuable insight into the immune function of MHC class I in the immune system of teleost.展开更多
The Yangtze River and its branches are important habitats for the Japanese Eel(Anguilla japonica),however,there are few data on gonadal development and silvering indices of eels during the downstream spawning migratio...The Yangtze River and its branches are important habitats for the Japanese Eel(Anguilla japonica),however,there are few data on gonadal development and silvering indices of eels during the downstream spawning migration.This study investigates gonadal development in 121 Japanese eels caught downstream from the Jingjiang Reach of the Yangtze River in October 2012.We found that in females the ovaries of most of the out-migrating population developed earlier than the testes in males,that is,the ovaries reached stage 3(F3)or early stage 4(eF4),while the testes were at stage 2(M2)or stage 3(M3).Gonadal development in eels collected in 2012 was earlier than that of samples caught from the same region in 2007e2008 and from the Pearl River Estuary in 1972e1973.The average age,body size and gonadal-somatic index of females were significantly greater than those in males.For both females and males,there were no significant differences between the two stages of gonadal development in any of the morphological indices,which indicates that gonadal development of the Japanese Eel is independent of body size.These results help us to understand the spawning population of Japanese Eels in the Yangtze River.展开更多
基金supported by the National Key R&D Program of China (No.2019YFD0900102)the Science and Technology Commission of Shanghai Municipality (Nos.17050502100 and 18391901500)+1 种基金the National Natural Resources Platform of ChinaKnowledge Service Platform of Shanghai Ocean University。
文摘Methylene blue(MB) is commonly used in aquaculture as a fungicide and antidotes. This study was designed to explore the pharmacokinetics of MB in Japanese eel(Anguilla Japonica) immersed in 10 mg L^-1 and 20 mg L^-1 MB for 0.5 h. The concentrations of MB and its derivatives in the blood, liver, kidney, skin and muscle were determined by HPLC after immersion. The results showed that the changes of drug concentrations in Japanese eel were basically the same in different dose groups, showing a general trend of increasing at first and then decreasing, but the peak time was slightly different. The peak concentration of the drug was positively correlated with the dose level. The peak concentrations of MB in MB(20 mg L^-1) group, MB, azure A and azure B in the tissues of Japanese eel were significantly higher than those in MB(10 mg L^-1) group. Moreover, MB, azure A and azure B remained for a long time and could still be detected at 64 days, and azure C was not detected in tissues.
基金Supported by the National Natural Science Foundation of China(NSFC)(No.41676137)the Creative Team Project of the Laboratory for Marine Ecology and Environmental Science,Qingdao National Laboratory for Marine Science and Technology(No.LMEES-CTSP-2018-1)。
文摘The Japanese eel(Anguilla japonica)is a commercially important fi sh species in East Asia and its recruitment has been rapidly declining since 1990s.Clarifying the genetic population structure of A.japonica is the basis of multinational cooperation on its management and protection,due to its large distribution range.Gene-associated markers have been proved powerful in delineating fi ne-scale population genetic structure and spatially varying selection.In the present study,we developed 24 polymorphic gene-associated microsatellite markers including 18 loci associated with the genes under selection in the two North Atlantic eel species(Anguilla anguilla and Anguilla rostrata)and 6 loci based on transcript sequences.A total of 13 geographic populations were sampled across its distribution range,including 11 samples from China(9 from China’s mainland and 2 from Taiwan region),and 2 samples from Japan.A total of 416 individuals(mostly glass eels)were collected and genotyped at the 24 microsatellites.All measures of diff erentiation were accordant with a panmictic scenario(F ST=-0.001)in A.japonica.No footprints of spatially varying selection were found,indicating that the selection pattern in A.japonica might be diff erent from that in the two North Atlantic eel species.We suggest that A.japonica should be managed as a single unit and management and conservation eff orts must be coordinated at the international level,as overexploitation in any region will decrease its recruitment across the whole distributional range.
基金Supported by the Ocean and Fishery Bureau of Fujian Province(No.201212140006)the Scientific Research Foundation of Jimei University,China(No.ZQ2008013)+1 种基金the National Natural Science Foundation of China(No.31272685)the Program of the Education Department of Fujian Province(No.JA11150)
文摘As a potent pleiotropic cytokine, tumor necrosis factor-alpha(TNF-α) plays an important role in innate immune responses. The cDNA sequence and genomic structure of the TNF-α gene( Aj TNF-α) in the Japanese eel( Anguilla japonica) were identified and characterized. The full-length Aj TNF-α cDNA was 1 546 bp, including a 5′-untranslated region(UTR) of 13 bp, a 3′-UTR of 879 bp and an open reading frame of 654 bp encoding a protein of 218 amino acids. The full-length genomic sequence of Aj TNF-α was 2 392 bp and included four exons and three introns. The putative Aj TNF-α protein contained TNF family signature motifs, including a protease cleavage site, a transmembrane domain and two conserved cysteine residues. Quantitative real-time reverse transcription PCR analysis revealed Aj TNF-α expression in a wide range of tissues, with predominant expression in blood and liver. Lower levels of expression were seen in spleen, gills, kidney, intestine, heart, and skin, with very low levels in muscle. The modulation of Aj TNF-α expression after injection of eels with lipopolysaccharide(LPS), the viral mimic, poly I:C, or Aeromonas hydrophila was assessed in blood, liver, and kidney. In blood, TNF-α mRNA levels increased rapidly and then rapidly decreased after stimulation with LPS, poly I:C or A. hydrophila. However, the response to LPS and A. hydrophila peaked at 6 h while for poly I:C the peak was at 12 h. In liver, after injection with A. hydrophila, an up- and down-regulation of Aj TNF-α expression occurred twice, peaking at 6 h and 24 h, respectively. No remarkable increase of Aj TNF-α expression appeared in liver until 72 h after LPS or poly I:C treatment. In kidney, Aj TNF-α expression increased significantly only at 72 h post-stimulation with LPS or A. hydrophila. Our results suggest that Aj TNF-α plays an important role in fish in the defense against viral and bacterial infection.
基金supported by“Nature Science Foundation of Fujian Province”(No.2020J01671)“The Science Foundation of Jimei University,China”(No.ZP2020017)+1 种基金“Engineering Research Center of the Modern Technology for Eel Industry,Ministry of Education,P.R.China”(No.RE202110)“Key Laboratory and Healthy Mariculture for the East China Sea,Ministry of Agriculture and Rural Affairs,P.R.China”(No.2020ESHML02).
文摘Major histocompatibility complex(MHC)molecules play a critical role in the immune response of vertebrate animals by presenting foreign antigens to T lymphocytes.In this study,we first cloned and identified a classical and a novel nonclassical MHC Iαmolecules from Japanese eel(Anguilla japonica),named as AjMHC I-UBA and AjMHC I-L,respectively.The full-length cDNA of AjMHC I-UBA contains an open reading frame(ORF)of 1047 bp encoding a predicted protein of 348 amino acids,while AjMHC I-L 1089 bp encodes 362 amino acids.The multiple alignment of the amino acid sequence showed that AjMHC I-UBA and AjMHC I-L consist of an N-terminal MHC I superfamily domain withinα1 andα2 helices,an IgC-MHC Iα3 domain,and a transmembrane region close to the C-terminal,which are similar to other fish and mammal species.Molecular polymorphism analysis showed that eight different major alleles of AjMHC I-UBA,named as AjMHC I-UBA*0101~1001,were identified from six Japanese eel individuals.Furthermore,a distinguishing signature of the nonclassical L-lineage genes specific motif“HINMTL”,including an N-glycosylation site(NXS/T),was present in theα3 domain of AjMHC I-L sequences.Although the predicted three-dimensional structures of AjMHC I-UBA and AjMHC I-L are similar to that of human MHC Iα,phylogenetic analysis showed that these two protein molecules belong to classical MHC I UBA gene of U-lineage and nonclassical MHC I gene of L-lineage,respectively.Quantitative real-time polymerase chain reaction(qRT-PCR)analysis revealed that the highest expression of AjMHC I-UBA and AjMHC I-L was found in the intestine and the expression level of AjMHC I-UBA in all of the examined tissues was significantly higher than that of AjMHC I-L.The expressions of AjMHC I-UBA and AjMHC I-L in liver,kidney and spleen were significantly induced following injection with the viral mimic poly I:C,LPS,and Aeromonas hydrophila infection.In vitro,the AjMHC I-UBA and AjMHC I-L transcripts of Japanese eel liver cells were significantly enhanced by the treatment of poly I:C or the stimulation of the high concentration of A.hydrophila.Subcellular localization showed that under natural conditions,AjMHC I-UBA and AjMHC I-L were uniformly distributed in the cytoplasm,and aggregated into spots or flakes in the cytoplasm after the stimulation of poly I:C or LPS.These results collectively suggested that AjMHC I-UBA and AjMHC I-L are important components possibly involved in Japanese eel defense against viral and bacterial infection.Taken together,these findings provide valuable insight into the immune function of MHC class I in the immune system of teleost.
基金This study was supported by the National Natural Science Foundation of China(No.31201995)the Shanghai Municipal Agricultural Commission(No.20132-2)+1 种基金the Shanghai Municipal Science and Technology Commission of Chongming(No.13231203504)the Open Foundation of Engineering Research Centre of Modern Industrial Technology for Eels,Ministry of Education,China(No.RE201501).
文摘The Yangtze River and its branches are important habitats for the Japanese Eel(Anguilla japonica),however,there are few data on gonadal development and silvering indices of eels during the downstream spawning migration.This study investigates gonadal development in 121 Japanese eels caught downstream from the Jingjiang Reach of the Yangtze River in October 2012.We found that in females the ovaries of most of the out-migrating population developed earlier than the testes in males,that is,the ovaries reached stage 3(F3)or early stage 4(eF4),while the testes were at stage 2(M2)or stage 3(M3).Gonadal development in eels collected in 2012 was earlier than that of samples caught from the same region in 2007e2008 and from the Pearl River Estuary in 1972e1973.The average age,body size and gonadal-somatic index of females were significantly greater than those in males.For both females and males,there were no significant differences between the two stages of gonadal development in any of the morphological indices,which indicates that gonadal development of the Japanese Eel is independent of body size.These results help us to understand the spawning population of Japanese Eels in the Yangtze River.
