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Akira Goto - One of the best experts on this subject based on the ideXlab platform.
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polymorphic spawning nest types in a local population of the fluvial sculpin cottus nozawae teleostei Cottidae
Ichthyological Research, 2013Co-Authors: Masayuki Kumagai, Akira Goto, Hideki SugiyamaAbstract:The nesting behavior of a fluvial sculpin Cottus nozawae population was investigated in a stream–reservoir system on the Sainai River, northern Honshu Island, Japan in 2003, 2004 and 2006. Except for the usual rock nest-spawning type (RSN), two new types of spawning nest were found: hole nest spawning (HNS) and crevice nest spawning (CNS). The HNS type was characterized by males digging one or more nest holes in the wall of the banks of the stream and reservoir, or on the sandy silt bottom of the reservoir. The CNS type involved the use of a crevice between large boulders or crevice of crag for their nests. The HNS type was dominant in the reservoir section, whereas the RNS type was dominant in the rapid riffles of stream sections. The HNS and CNS types appeared to be rarely or first observed in the Cottus species. These new nest-spawning types might have occurred in relation to the artificial environment changes in the river by dam construction.
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Broad-scale phylogeography of the Palearctic freshwater fish Cottus poecilopus complex (Pisces: Cottidae).
Molecular Phylogenetics and Evolution, 2008Co-Authors: Ryota Yokoyama, Valentina G. Sideleva, S. V. Shedko, Akira GotoAbstract:Because freshwater fishes only use freshwater drainages for their colonization, phylogeographic patterns of them have been interpreted in conjunction with physical evidence of historical drainage patterns. The phylogeography of freshwater fishes has an important role in understanding the formation of regional biodiversity. In North America and Europe, numerous studies of phylogeography of freshwater fishes have clarified lineage distributions and colonization histories of them with reference to drastic disturbance during glacial cycles in Pleistocene (reviewed in Bernatchez and Wilson, 1998; Hewitt, 2004). In contrast to North America and Europe, few studies have been on fishes in Siberia and northeastern Asia. Phylogeographic patterns of Siberian fishes were partially discussed in studies of Holarctic fishes, such as of Arctic charr (Brunner et al., 2001), whitefish (Bernatchez and Dodson, 1994) and burbot (Van Houdt et al., 2003). In these studies, populations in Siberia comprise a single lineage (Siberian lineage) that has less diversity among populations. These studies suggest simpler phylogeography of fishes in Siberia despite their geographical width. On the other hand, the Arctic grayling, Thymallus arcticus, is genetically polymorphic in Siberia, suggesting the existence of several refugia in Siberia (Froufe et al., 2003, 2005; Weiss et al., 2006). General patterns of freshwater fish phylogeography in Siberia seem to be far from resolved.
Ryota Yokoyama - One of the best experts on this subject based on the ideXlab platform.
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mitochondrial dna analysis reveals a unique population structure of the amphidromous sculpin cottus pollux middle egg type teleostei Cottidae
Molecular Phylogenetics and Evolution, 2011Co-Authors: Hideharu Tsukagoshi, Ryota Yokoyama, A GotoAbstract:In this study, we examined nucleotide sequences from the first half of the mitochondrial control region gene to test for genetic differentiation in an amphidromous sculpin, Cottus pollux middle-egg type (ME) (Cottidae), obtained from 19 localities across its distribution range. Spatial analysis of molecular variance revealed five divergent groups of related haplotypes among this populations. Analysis with Migrate software revealed that gene flow was quite restricted among the groups, although it occurred practically between neighboring groups. It has previously been reported that the population structure among the amphidromous fishes of the various islands is low or non-existent, and is characterized mainly by the duration of the pelagic larval life. However, the present study demonstrated that the various C. pollux ME populations were different both among the islands, and within the island of the Japanese Archipelago. Our finding indicate that the unique population structure of C. pollux ME may be influenced not only by the extent of the pelagic larval phase of the species but also by the seasonal differentiation of its dispersal phase.
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Broad-scale phylogeography of the Palearctic freshwater fish Cottus poecilopus complex (Pisces: Cottidae).
Molecular Phylogenetics and Evolution, 2008Co-Authors: Ryota Yokoyama, Valentina G. Sideleva, S. V. Shedko, Akira GotoAbstract:Because freshwater fishes only use freshwater drainages for their colonization, phylogeographic patterns of them have been interpreted in conjunction with physical evidence of historical drainage patterns. The phylogeography of freshwater fishes has an important role in understanding the formation of regional biodiversity. In North America and Europe, numerous studies of phylogeography of freshwater fishes have clarified lineage distributions and colonization histories of them with reference to drastic disturbance during glacial cycles in Pleistocene (reviewed in Bernatchez and Wilson, 1998; Hewitt, 2004). In contrast to North America and Europe, few studies have been on fishes in Siberia and northeastern Asia. Phylogeographic patterns of Siberian fishes were partially discussed in studies of Holarctic fishes, such as of Arctic charr (Brunner et al., 2001), whitefish (Bernatchez and Dodson, 1994) and burbot (Van Houdt et al., 2003). In these studies, populations in Siberia comprise a single lineage (Siberian lineage) that has less diversity among populations. These studies suggest simpler phylogeography of fishes in Siberia despite their geographical width. On the other hand, the Arctic grayling, Thymallus arcticus, is genetically polymorphic in Siberia, suggesting the existence of several refugia in Siberia (Froufe et al., 2003, 2005; Weiss et al., 2006). General patterns of freshwater fish phylogeography in Siberia seem to be far from resolved.
Jeffrey G Richards - One of the best experts on this subject based on the ideXlab platform.
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species and tissue specific differences in ros metabolism during exposure to hypoxia and hyperoxia plus recovery in marine sculpins
The Journal of Experimental Biology, 2019Co-Authors: Gigi Y Lau, Sabine Arndt, Michael P Murphy, Jeffrey G RichardsAbstract:ABSTRACT Animals that inhabit environments that fluctuate in oxygen must not only contend with disruptions to aerobic metabolism, but also the potential effects of reactive oxygen species (ROS). The goal of this study was to compare aspects of ROS metabolism in response to O2 variability (6 h hypoxia or hyperoxia, with subsequent normoxic recovery) in two species of intertidal sculpin fishes (Cottidae, Actinopterygii) that can experience O2 fluctuations in their natural environment and differ in whole-animal hypoxia tolerance. To assess ROS metabolism, we measured the ratio of glutathione to glutathione disulfide as an indicator of tissue redox environment, MitoP/MitoB ratio to assess in vivo mitochondrial ROS generation, thiobarbituric acid reactive substances (TBARS) for lipid peroxidation, and total oxidative scavenging capacity (TOSC) in the liver, brain and gill. In the brain, the more hypoxia-tolerant Oligocottusmaculosus showed large increases in TBARS levels following hypoxia and hyperoxia exposure that were generally not associated with large changes in mitochondrial H2O2. In contrast, the less-tolerant Scorpaenichthysmarmoratus showed no significant changes in TBARS or mitochondrial H2O2 in the brain. More moderate increases were observed in the liver and gill of O. maculosus exposed to hypoxia and hyperoxia with normoxic recovery, whereas S. marmoratus had a greater response to O2 variability in these tissues compared with the brain. Our results show a species- and tissue-specific relationship between hypoxia tolerance and ROS metabolism.
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evolution of cytochrome c oxidase in hypoxia tolerant sculpins Cottidae actinopterygii
Molecular Biology and Evolution, 2017Co-Authors: Milica Mandic, Jeffrey G RichardsAbstract:: Vertebrate hypoxia tolerance can emerge from modifications to the oxygen (O2) transport cascade, but whether there is adaptive variation to O2 binding at the terminus of this cascade, mitochondrial cytochrome c oxidase (COX), is not known. In order to address the hypothesis that hypoxia tolerance is associated with enhanced O2 binding by mitochondria we undertook a comparative analysis of COX O2 kinetics across species of intertidal sculpins (Cottidae, Actinopterygii) that vary in hypoxia tolerance. Our analysis revealed a significant relationship between hypoxia tolerance (critical O2 tension of O2 consumption rate; Pcrit), mitochondrial O2 binding affinity (O2 tension at which mitochondrial respiration was half maximal; P50), and COX O2-binding affinity (apparent Michaelis-Menten constant for O2 binding to COX; Km,app O2). The more hypoxia tolerant species had both a lower mitochondrial P50 and lower COX Km,app O2, facilitating the maintenance of mitochondrial function to a lower O2 tension than in hypoxia intolerant species. Additionally, hypoxia tolerant species had a lower overall COX Vmax but higher mitochondrial COX respiration rate when expressed relative to maximal electron transport system respiration rate. In silico analyses of the COX3 subunit postulated as the entry point for O2 into the COX protein catalytic core, points to variation in COX3 protein stability (estimated as free energy of unfolding) contributing to the variation in COX Km,app O2. We propose that interactions between COX3 and cardiolipin at four amino acid positions along the same alpha-helix forming the COX3 v-cleft represent likely determinants of interspecific differences in COX Km,app O2.
Arneberg Per - One of the best experts on this subject based on the ideXlab platform.
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Gyrodactylus triglopsi n. sp. (Monogenea: Gyrodactylidae) from the Gills of Triglops nybelini Jensen, 1944 (Teleostei: Cottidae) in the Barents Sea
'Walter de Gruyter GmbH', 2020Co-Authors: Hansen Haakon, Alvestad, Anja Helene, Mackenzie Ken, Darrud Mari, Karlsbakk Egil, Hemmingsen Willy, Arneberg PerAbstract:Introduction - Monogeneans of the genus Gyrodactylus were found on the gills of specimens of the bigeye sculpin Triglops nybelini Jensen, 1944 caught by trawl in the Barents Sea in January–February 2016. Methods - Morphological preparations of the parasites were examined and photographed under a microscope at magnifcations of×100–1000 and morphometric analyses were carried out on 22 specimens using ImageJ2 software. Eight of the specimens used for the morphological comparisons were also subjected to molecular analyses by sequencing a region of the ribosomal DNA spanning partial 18S, the internal transcribed spacers 1 and 2 (ITS1 and 2), 5.8S and partial 28S and comparing this with other species through a BlastN-search in GenBank and through phylogenetic analyses. Results - The morphology of the species from T. nybelini was markedly diferent to that of any of other species of Gyrodactylus. It is characterized by having relatively long hamulus roots, a character that it shares with two other species described from marine sculpins (Cottidae); G. armatus and G. maculosi. It also has a narrow rectangular ventral bar membrane with a posterior notch which it shares with G. maculosi only. Compared with all the seven species from marine Cottidae described so far, it has the smallest opisthaptoral hard parts. A comparison of the internal transcribed spacer (ITS) rDNA sequence with available sequences in GenBank and a phylogenetic analyses also showed it to be highly divergent from other sequences. Therefore, a new species is proposed, Gyrodactylus triglopsi n. sp. Conclusion - Both the morphological and molecular analyses support the status of G. triglopsi as a new species. This is to our knowledge the frst species of Gyrodactylus described from Triglops nybelini and the description extends the list of Gyrodactylus species found on fsh in the Barents Sea to 17
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Gyrodactylus triglopsi n. sp. (Monogenea: Gyrodactylidae) from the Gills of Triglops nybelini Jensen, 1944 (Teleostei: Cottidae) in the Barents Sea
'Walter de Gruyter GmbH', 2020Co-Authors: Hansen Haakon, Alvestad, Anja Helene, Mackenzie Ken, Darrud Mari, Karlsbakk Egil, Hemmingsen Willy, Arneberg PerAbstract:Introduction Monogeneans of the genus Gyrodactylus were found on the gills of specimens of the bigeye sculpin Triglops nybelini Jensen, 1944 caught by trawl in the Barents Sea in January–February 2016. Methods Morphological preparations of the parasites were examined and photographed under a microscope at magnifications of × 100–1000 and morphometric analyses were carried out on 22 specimens using ImageJ2 software. Eight of the specimens used for the morphological comparisons were also subjected to molecular analyses by sequencing a region of the ribosomal DNA spanning partial 18S, the internal transcribed spacers 1 and 2 (ITS1 and 2), 5.8S and partial 28S and comparing this with other species through a BlastN-search in GenBank and through phylogenetic analyses. Results The morphology of the species from T. nybelini was markedly different to that of any of other species of Gyrodactylus. It is characterized by having relatively long hamulus roots, a character that it shares with two other species described from marine sculpins (Cottidae); G. armatus and G. maculosi. It also has a narrow rectangular ventral bar membrane with a posterior notch which it shares with G. maculosi only. Compared with all the seven species from marine Cottidae described so far, it has the smallest opisthaptoral hard parts. A comparison of the internal transcribed spacer (ITS) rDNA sequence with available sequences in GenBank and a phylogenetic analyses also showed it to be highly divergent from other sequences. Therefore, a new species is proposed, Gyrodactylus triglopsi n. sp. Conclusion Both the morphological and molecular analyses support the status of G. triglopsi as a new species. This is to our knowledge the first species of Gyrodactylus described from Triglops nybelini and the description extends the list of Gyrodactylus species found on fish in the Barents Sea to 17.publishedVersio
Ignacio Doadrio - One of the best experts on this subject based on the ideXlab platform.
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UGROŽENE VRSTE RIBA U SVIJETU: Cottus hispaniolensis Bacescu-Mester, 1964 (Cottidae)
'Croatian Journal of Fisheries', 2014Co-Authors: Carla Sousa-santos, Joana Isabel Robalo, Ana Pereira, Ignacio DoadrioAbstract:Cottus hispaniolensis is a critically endangered cottid fish which is endemic from the Pyrenanean Garonne river basin.Cottus hispaniolensis je kritično ugrožena vrsta ribe iz porodice Cottidae, a endemska je u slivu pirenejske rijeke Garonne
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UGROŽENE VRSTE RIBA U SVIJETU: Cottus aturi Freyhof, Kottelat i Nolte 2005 (Cottidae)
'Croatian Journal of Fisheries', 2014Co-Authors: Carla Sousa-santos, Joana Isabel Robalo, Ana Pereira, Ignacio DoadrioAbstract:Cottus aturi is an endemic cottid fish from three small Pyrenean river basins and is critically endangered mainly due to water quality degradation related to reduced flow and eutrophication.Cottus aturi je endemska vrsta ribe iz porodice Cottidae iz tri mala pirenejska riječna sliva i kritično je ugrožena najviše zbog degradirane kvalitete vode povezane sa smanjenim protokom i eutrofikacijom
