- Email: [email protected]
Energy metabolism for ion regulation in fish gills
464
Abstracts
Surface seawater samples were collected and analyzed for organotin compounds using SPE-GC-FPD in Xiamen and HongKong sea area. The total concentrations of organotin compounds varied in the range of 50.82–90.39 ng (Sn)/L in Xiamen sea area and 480.41–1110.97 ng(Sn)/L in Hong Kong sea area, respectively. It was obvious that the contamination of organotin compounds in surface seawater from Xiamen sea area was heavier than in Hong Kong sea area. The degree of imposex of T. clavigera at nine stations near Xiamen sea area, six stations near Hong Kong sea area were assessed using the Index of imposex (IOI), Relative Penis Size Index (RPSI), the Vas Deferens development sequence index (VDSI) and Sex ratios (SR). All sites showed some degree of imposex development in both of Xiamen and HongKong sea area. In Xiamen sea area, the most affected areas were Baozhu isle, Jingtai isle and Huoshao isle, which were located in the inner Western Harbor. The IOI of T. clavigera in Baicheng and Huangcuo were relatively low, 23.81%and 31.58% respectively. The VDSI were less than 2 except that in Bozhu isle and Jingtai isle with 3.10 and 4.00 respectively. However, IOI in most sampling stations from Hong kong sea area were 100% especially in Shek O with 33.3%. In Sam Mun Tsai, the VDSI exceeded 5 and observed the phenomenon of jammed reproductive hole and yeld yolk vesicle on T. clavigera. These results showed that the seawater either in Xiamen or in Hongkong was contaminated by the toxic organotin compounds. The contamination in Hongkong was heavier than Xiamen and resulted in the imposex degree of T. clavigera in Hong Kong was more serious than Xiamen.
Recently, a novel glycogen phosphorylase isoform (tGPGG), which catalyzes the initial degradation of glycogen, was identified in tilapia (Oreochormis mossambicus) gill. Double in situ hybridization and immunocytochemistry demonstrated that tGPGG mRNA and glycogen were colocalized in a specific group of gill cells, glycogen-rich (GR) cells, which surround mitochondria-rich (MR) cells. Acclimation to seawater stimulated tGPGG mRNA/protein expression levels, enzyme activities, and glycogen contents in tilapia gills. In acute salinity transfer experiments, following the rapid increase in gill Na+–K+-ATP activity, glycogen depletion initially appeared 1–3 h post-transfer in gills (i.e., GR cells) and thereafter at 6–12 h in the liver; moreover, GP activities in the gills and liver were also accordingly stimulated. In subsequent experiments, we also identified several carbohydrate transporters, glucose transporters (GLUTs, SLC2A) and monocarboxylate transporters (MCTs, SLC16A), which are specifically expressed in gill ionocytes and are associated with the functions of the ionocytes. These results outline a model for the local (gill GR cells) and systemic (liver cells) partitioning of glycogen metabolism, which provides emergency energy for osmoregulation by gill MR cells.
doi:10.1016/j.cbpc.2008.10.059
Bruce L. Tufts Department of Biology, Queen's University, Kingston, Ontario, Canada K7L 3N6 E-mail: [email protected]
MOLECULAR CHARACTERIZATION AND EXPRESSION OF A NOVEL VITELLOGENIN GENE IN THE FRESHWATER GIANT PRAWN, MACROBRACHIUM ROSENBERGII Deng-Yu Tsenga, Ching-Ming Kuob a Graduate Institute of Biological Resources and Technology, National University of Tainan, Tainan 700, Taiwan b Institute of Cellular and Organismic Biology, Academia Sinica, Taipei 115, Taiwan E-mail: [email protected] The reproductive functions and mechanisms regulating vitellogenesis in crustaceas have been the subjects of controversy. We have cloned another type of vitellogenin cDNA (Vg2) another than Vg1 being described previously in freshwater giant prawn, Macrobrachium rosenbergii, and proven that Vg1 and Vg2 are simultaneously expressed. The similarity of the freshwater giant prawn Vg1 and Vg2 is as high as 94%, but the partial sequence of Vg2 fragment with 19 aa differs from that in Vg1. There are five amino acids are different and one is lost within the signal peptide of Vg2 N-terminal sequence compare to Vg1. The sequenced cDNA of Vg1 consisted of 7800 bp, contains a 2538 aa open reading frame which shows similarity to vitellogenin sequenes from other crustaceans. Its deduced amino acid sequence possessed three consensus cleavage sites, RXRR, similar to those reported in Vgs of insects. The freshwater giant prawn Vg2 has six potential N-glycosylation sites, five of which were obtained in VnA and one in VnC. Sixteen residues of Cysteine having the potential for the disulphide bound formation within VnA, are existed in Vg1 and conserved well in vitellogenins from other crustaceans. Three histidine cluster motifs (HXXXXH, HXXXH and HXXHH) that are essential for catalysis of stearoyl-CoA desaturase activity were found in the deduced amino acid sequence of Vg2.
doi:10.1016/j.cbpc.2008.10.061
COMPARATIVE PHYSIOLOGY IN FISHERIES MANAGEMENT
Many of the world's wild fish populations have become overexploited or endangered as a result of human activities. While this situation is most widely publicized for ocean environments, it is also the case in many freshwater environments. The main reason for these declines can often be attributed to a long history of over-harvest in both commercial and recreational fisheries. In many areas, habitat degradation has also been an important factor contributing to this problem. On this broad background, this talk will discuss several ways that comparative physiology can be used to address important issues that contribute to the conservation of the world's wild fish stocks. In both commercial and recreational fisheries, an essential management tool to protect fish populations is selective harvest. Although fisheries incorporating selective harvest rely on the release of non-targeted individuals, survival of these fish is not always guaranteed. Our lab has used comparative physiology to examine ways that non-targeted individuals that are caught in these fisheries can be released in the best possible condition. Much of this research has been applied to recreational fisheries, but many of the results are also applicable to commercial fisheries. Similar approaches have also been used by other researchers to address problems associated with commercial fisheries. Another strategy that has the potential to protect wild fish populations and also provide a growing human population with fish protein is aquaculture. Around the globe, a large number of countries are therefore trying to rapidly develop their abilities in this area. At the present time, however, there are still many important issues that need to be resolved in order to maximize the potential of this massive industry. In this regard, our lab has become involved in using comparative physiology to improve our ability to grow fish in captivity. The different approaches that comparative physiologist have been developing in this area will also be discussed. doi:10.1016/j.cbpc.2008.10.062
doi:10.1016/j.cbpc.2008.10.060
ENERGY METABOLISM FOR ION REGULATION IN FISH GILLS Yung-Che Tsenga,b, Joshu Changa, Chia-Hsib, Pung-Pung Hwangb a Institute of Zoology, National Taiwan University, Nankang, Taipei, 10617, Taiwan b Institute of Cellular and Organismic Biology, Academia Sinica, Nankang, Taipei, 11529, Taiwan E-mail: [email protected] The timely and sufficiently energy supply is crucial for the modulation and stimulation of ion transport mechanisms in fish gills. Carbohydrate, playing a central role in providing energy metabolism, is primarily stored as glycogen.
COMPARISON OF THE MECHANISMS OF AMMONIA TOLERANCE IN UREOTELIC (TOADFISH) VERSUS AMMONIOTELIC (MIDSHIPMAN) FISH Patrick J. Walsha,b, Clemence Veauvyb, Dirk Weihrauchc a Department of Biology, University of Ottawa, Ottawa, Ontario Canada K1N 6N5 b Division of Marine Biology and Fisheries, Rosenstiel School of Marine and Atmospheric Science, University of Miami, Miami, Florida 33149-1098, USA c Department of Biological Sciences, University of Manitoba, Winnipeg, MB, Canada R3T 2N2 E-mail: [email protected] Fishes of the family Batrachoididae (toadfish and midshipmen) show much higher tolerance to ammonia than most previously studied teleostean
Abstracts
Surface seawater samples were collected and analyzed for organotin compounds using SPE-GC-FPD in Xiamen and HongKong sea area. The total concentrations of organotin compounds varied in the range of 50.82–90.39 ng (Sn)/L in Xiamen sea area and 480.41–1110.97 ng(Sn)/L in Hong Kong sea area, respectively. It was obvious that the contamination of organotin compounds in surface seawater from Xiamen sea area was heavier than in Hong Kong sea area. The degree of imposex of T. clavigera at nine stations near Xiamen sea area, six stations near Hong Kong sea area were assessed using the Index of imposex (IOI), Relative Penis Size Index (RPSI), the Vas Deferens development sequence index (VDSI) and Sex ratios (SR). All sites showed some degree of imposex development in both of Xiamen and HongKong sea area. In Xiamen sea area, the most affected areas were Baozhu isle, Jingtai isle and Huoshao isle, which were located in the inner Western Harbor. The IOI of T. clavigera in Baicheng and Huangcuo were relatively low, 23.81%and 31.58% respectively. The VDSI were less than 2 except that in Bozhu isle and Jingtai isle with 3.10 and 4.00 respectively. However, IOI in most sampling stations from Hong kong sea area were 100% especially in Shek O with 33.3%. In Sam Mun Tsai, the VDSI exceeded 5 and observed the phenomenon of jammed reproductive hole and yeld yolk vesicle on T. clavigera. These results showed that the seawater either in Xiamen or in Hongkong was contaminated by the toxic organotin compounds. The contamination in Hongkong was heavier than Xiamen and resulted in the imposex degree of T. clavigera in Hong Kong was more serious than Xiamen.
Recently, a novel glycogen phosphorylase isoform (tGPGG), which catalyzes the initial degradation of glycogen, was identified in tilapia (Oreochormis mossambicus) gill. Double in situ hybridization and immunocytochemistry demonstrated that tGPGG mRNA and glycogen were colocalized in a specific group of gill cells, glycogen-rich (GR) cells, which surround mitochondria-rich (MR) cells. Acclimation to seawater stimulated tGPGG mRNA/protein expression levels, enzyme activities, and glycogen contents in tilapia gills. In acute salinity transfer experiments, following the rapid increase in gill Na+–K+-ATP activity, glycogen depletion initially appeared 1–3 h post-transfer in gills (i.e., GR cells) and thereafter at 6–12 h in the liver; moreover, GP activities in the gills and liver were also accordingly stimulated. In subsequent experiments, we also identified several carbohydrate transporters, glucose transporters (GLUTs, SLC2A) and monocarboxylate transporters (MCTs, SLC16A), which are specifically expressed in gill ionocytes and are associated with the functions of the ionocytes. These results outline a model for the local (gill GR cells) and systemic (liver cells) partitioning of glycogen metabolism, which provides emergency energy for osmoregulation by gill MR cells.
doi:10.1016/j.cbpc.2008.10.059
Bruce L. Tufts Department of Biology, Queen's University, Kingston, Ontario, Canada K7L 3N6 E-mail: [email protected]
MOLECULAR CHARACTERIZATION AND EXPRESSION OF A NOVEL VITELLOGENIN GENE IN THE FRESHWATER GIANT PRAWN, MACROBRACHIUM ROSENBERGII Deng-Yu Tsenga, Ching-Ming Kuob a Graduate Institute of Biological Resources and Technology, National University of Tainan, Tainan 700, Taiwan b Institute of Cellular and Organismic Biology, Academia Sinica, Taipei 115, Taiwan E-mail: [email protected] The reproductive functions and mechanisms regulating vitellogenesis in crustaceas have been the subjects of controversy. We have cloned another type of vitellogenin cDNA (Vg2) another than Vg1 being described previously in freshwater giant prawn, Macrobrachium rosenbergii, and proven that Vg1 and Vg2 are simultaneously expressed. The similarity of the freshwater giant prawn Vg1 and Vg2 is as high as 94%, but the partial sequence of Vg2 fragment with 19 aa differs from that in Vg1. There are five amino acids are different and one is lost within the signal peptide of Vg2 N-terminal sequence compare to Vg1. The sequenced cDNA of Vg1 consisted of 7800 bp, contains a 2538 aa open reading frame which shows similarity to vitellogenin sequenes from other crustaceans. Its deduced amino acid sequence possessed three consensus cleavage sites, RXRR, similar to those reported in Vgs of insects. The freshwater giant prawn Vg2 has six potential N-glycosylation sites, five of which were obtained in VnA and one in VnC. Sixteen residues of Cysteine having the potential for the disulphide bound formation within VnA, are existed in Vg1 and conserved well in vitellogenins from other crustaceans. Three histidine cluster motifs (HXXXXH, HXXXH and HXXHH) that are essential for catalysis of stearoyl-CoA desaturase activity were found in the deduced amino acid sequence of Vg2.
doi:10.1016/j.cbpc.2008.10.061
COMPARATIVE PHYSIOLOGY IN FISHERIES MANAGEMENT
Many of the world's wild fish populations have become overexploited or endangered as a result of human activities. While this situation is most widely publicized for ocean environments, it is also the case in many freshwater environments. The main reason for these declines can often be attributed to a long history of over-harvest in both commercial and recreational fisheries. In many areas, habitat degradation has also been an important factor contributing to this problem. On this broad background, this talk will discuss several ways that comparative physiology can be used to address important issues that contribute to the conservation of the world's wild fish stocks. In both commercial and recreational fisheries, an essential management tool to protect fish populations is selective harvest. Although fisheries incorporating selective harvest rely on the release of non-targeted individuals, survival of these fish is not always guaranteed. Our lab has used comparative physiology to examine ways that non-targeted individuals that are caught in these fisheries can be released in the best possible condition. Much of this research has been applied to recreational fisheries, but many of the results are also applicable to commercial fisheries. Similar approaches have also been used by other researchers to address problems associated with commercial fisheries. Another strategy that has the potential to protect wild fish populations and also provide a growing human population with fish protein is aquaculture. Around the globe, a large number of countries are therefore trying to rapidly develop their abilities in this area. At the present time, however, there are still many important issues that need to be resolved in order to maximize the potential of this massive industry. In this regard, our lab has become involved in using comparative physiology to improve our ability to grow fish in captivity. The different approaches that comparative physiologist have been developing in this area will also be discussed. doi:10.1016/j.cbpc.2008.10.062
doi:10.1016/j.cbpc.2008.10.060
ENERGY METABOLISM FOR ION REGULATION IN FISH GILLS Yung-Che Tsenga,b, Joshu Changa, Chia-Hsib, Pung-Pung Hwangb a Institute of Zoology, National Taiwan University, Nankang, Taipei, 10617, Taiwan b Institute of Cellular and Organismic Biology, Academia Sinica, Nankang, Taipei, 11529, Taiwan E-mail: [email protected] The timely and sufficiently energy supply is crucial for the modulation and stimulation of ion transport mechanisms in fish gills. Carbohydrate, playing a central role in providing energy metabolism, is primarily stored as glycogen.
COMPARISON OF THE MECHANISMS OF AMMONIA TOLERANCE IN UREOTELIC (TOADFISH) VERSUS AMMONIOTELIC (MIDSHIPMAN) FISH Patrick J. Walsha,b, Clemence Veauvyb, Dirk Weihrauchc a Department of Biology, University of Ottawa, Ottawa, Ontario Canada K1N 6N5 b Division of Marine Biology and Fisheries, Rosenstiel School of Marine and Atmospheric Science, University of Miami, Miami, Florida 33149-1098, USA c Department of Biological Sciences, University of Manitoba, Winnipeg, MB, Canada R3T 2N2 E-mail: [email protected] Fishes of the family Batrachoididae (toadfish and midshipmen) show much higher tolerance to ammonia than most previously studied teleostean