JC Gwo
National Taiwan Ocean University, Aquaculture, Faculty Member
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In this study, DNA analyses were employed to verify the identity of six morphologically similar species that occur in the coastal waters of Taiwan: the black seabream complex (Acanthopagrus latus, Acanthopagrus schlegelii, Acanthopagrus... more
In this study, DNA analyses were employed to verify the identity of six morphologically similar species that occur in the coastal waters of Taiwan: the black seabream complex (Acanthopagrus latus, Acanthopagrus schlegelii, Acanthopagrus sivicolus, Acanthopagrus taiwanensis, Acanthopagrus chinshira and Acanthopagrus pacificus). Amplified fragment-length polymorphism (AFLP) analyses clearly distinguished the same six species that are morphologically diagnosable based on subtle differences in scale counts and anal-fin colouration. In contrast, mitochondrial DNA analyses based on cytochrome b gene sequences did not distinguish individuals of A. schlegelii and A. sivicolus, reflecting either historical introgression or recent speciation and incomplete sorting of their mitochondrial lineages. Phylogenetic relationships among these six north-west Pacific Ocean species of Acanthopagrus analysed using AFLP data were consistent with scale rows above the lateral line (TRac), sperm ultrastructure and geographical distribution. The study provides molecular tools for future research relevant to improved management of these resources, and an increased understanding of the evolutionary history of this radiation.
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Using transmission and scanning electron microscopy, we have described the mature spermatozoon of the bivalve Gafrarium tumidum (Heterodonta, Veneridae, Circinae) for the first time. The spermatozoon of G. tumidum is the ect-aquasperm... more
Using transmission and scanning electron microscopy, we have described the mature spermatozoon of the bivalve Gafrarium tumidum (Heterodonta, Veneridae, Circinae) for the first time. The spermatozoon of G. tumidum is the ect-aquasperm type. The head contains a slightly curved nucleus. At its apex is a short cone-shaped acrosome. The structure of the acrosome is typical of heterodont bivalves and two major components of the acrosome vesicle material can be distinguished. The midpiece is an annular band of five mitochondria which surround the centriole complex. Sperm ultrastructure of G. tumidum provides additional information for the existing Veneridae phylogeny.
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This study focuses on the strategy for the conservation of masu salmon, Oncorhynchus masou, in the northern part of the species range (via the masu populations in Sakhalin Oblast), based on data of its population structure. It is shown... more
This study focuses on the strategy for the conservation of masu salmon, Oncorhynchus masou, in the northern part of the species range (via the masu populations in Sakhalin Oblast), based on data of its population structure. It is shown that masu populations that inhabit different rivers genetically differ from each other in allele frequencies at microsatellite markers. In the Naiba River basin, at least two genetically distinct masu populations exist: in the upper reaches and in a tributary, the Bolshoy Takoy River. The masu populations on Iturup Island significantly differ from those on Sakhalin Island; within Sakhalin, the masu salmon from the Chernaya River in the southwestern part of the island is genetically distinct from the southeastern Sakhalin and Aniva Bay populations. The genetic diversity of Iturup populations is substantially lower than that on Sakhalin, probably due to their small sizes. The measures for the conservation and recovery of masu salmon populations should be based primarily on their own genetic resources, or, in the case of a lack of spawners, on the base populations of their ecological/geographical region. In the latter case, masu populations of large rivers can be considered as base ones: for southeastern Sakhalin, this is masu salmon of the Naiba River; for Aniva Bay, this is masu salmon of the Lyutoga River. Transplantation of fish, fertilized eggs, or any other genetic material from a population that is different genetically and inhabits the waters with different ecological gradients should be strongly restricted. The formosan masu salmon from Taiwan Island is studied as an example of a strict genetic isolate.
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Using transmission and scanning electron microscopy, we have described the mature spermatozoon of the bivalve Gafrarium tumidum (Heterodonta, Veneridae, Circinae) for the first time. The spermatozoon of G. tumidum is the ect-aquasperm... more
Using transmission and scanning electron microscopy, we have described the mature spermatozoon of the bivalve Gafrarium tumidum (Heterodonta, Veneridae, Circinae) for the first time. The spermatozoon of G. tumidum is the ect-aquasperm type. The head contains a slightly curved nucleus. At its apex is a short cone-shaped acrosome. The structure of the acrosome is typical of heterodont bivalves and two major components of the acrosome vesicle material can be distinguished. The midpiece is an annular band of five mitochondria which surround the centriole complex. Sperm ultrastructure of G. tumidum provides additional information for the existing Veneridae phylogeny.
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... SS Subramoniam Newton, Cryoprotectant toxicity in penaeid prawn embryos, Cryobiology 33 (1992), pp. 132177. MC Pillai and WH Clark Jr, Hatching envelope formation in shrimp (Sicyonia ingentis) ova:origin and sequential exocytosis of... more
... SS Subramoniam Newton, Cryoprotectant toxicity in penaeid prawn embryos, Cryobiology 33 (1992), pp. 132177. MC Pillai and WH Clark Jr, Hatching envelope formation in shrimp (Sicyonia ingentis) ova:origin and sequential exocytosis of cortical vesicles, Tissue Cell 20 ...
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With particular emphasis on mitochondria that may provide endogenous energy for spermatozoan motility, the morphological changes of the spermatozoa of three marine teleosts, black porgy (Acanthopagrus schlegelli), black grouper... more
With particular emphasis on mitochondria that may provide endogenous energy for spermatozoan motility, the morphological changes of the spermatozoa of three marine teleosts, black porgy (Acanthopagrus schlegelli), black grouper (Epinephelus malabaricus), and Atlantic croaker (Micropogonias undulatus), were compared either after activation in artificial sea water or when immersed in various osmotic pressure media. The midpieces of these three teleosts spermatozoa are composed of mitochondria surrounding the flagellum. Each mitochondrion is enclosed by distinct outer and inner membranes. The inner membrane separates the organelle's volume into two phases: the matrix and the intermembrane space. The inner membrane displays numerous infolding cristae that vary in number and shape and extend into the matrix. Following activation with artificial sea water, spermatozoa became motile and both the size and number of mitochondria decrease and then totally disappear. The present study strongly suggests that an energy source(s), responsible for motility, is located within the mitochondria in the midpiece of these three marine teleost spermatozoa.
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Using transmission and scanning electron microscopy, the mature spermatozoa of four bivalves of the family Veneridae--Gafrarium tumidum and Circe scripta (Circinae), Pitar sulfureum (Pitarinae) and Gomphina aequilatera (Tapetinae)--are... more
Using transmission and scanning electron microscopy, the mature spermatozoa of four bivalves of the family Veneridae--Gafrarium tumidum and Circe scripta (Circinae), Pitar sulfureum (Pitarinae) and Gomphina aequilatera (Tapetinae)--are described for the first time and compared with those of other bivalves, particularly other heterodonts. As our observations show, the spermatozoa of these four species are of the primitive type or ect-aquasperm form. The head contains a slightly curved nucleus with a short cone-shaped acrosome. The structure of the acrosome is typical of heterodont bivalves and two major components of the acrosomal vesicle material can be distinguished. The midpiece exhibits four or five mitochondria which surround the proximal and the distal centrioles. Variation in the shape and dimensions of the acrosomal vesicle and nucleus is substantial in these four Veneroidea species.
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Research Interests: Population Dynamics, Transmission Electron Microscopy, Cryopreservation, Endangered Species, Genetic Diversity, and 15 moreTheriogenology, Biological Sciences, Androgenesis, Hybrid, Animals, Male, Methanol, Fertility Rate, DMA, Genetic variation, Spermatozoa, Sperm Motility, Oncorhynchus, High risk, and Medical and Health Sciences
A single dose of LHRHa (D-Ala(6), des Gly(10)- LHRH-ethylamide; 100 mug/kg body weight); administered by intramuscular injection, effectively induced ovulation in the Atlantic croaker (Micropogonias undulatus ); 37 of 40 (92%) females... more
A single dose of LHRHa (D-Ala(6), des Gly(10)- LHRH-ethylamide; 100 mug/kg body weight); administered by intramuscular injection, effectively induced ovulation in the Atlantic croaker (Micropogonias undulatus ); 37 of 40 (92%) females were successfully hand-stripped and there was no mortality. A single dose of human chorionic gonadotropin (hCG; 500 IU/kg body weight) was successful in inducing oocyte hydration. However, only 16 of 30 (53%) females ovulated successfully and could be hand-stripped. Another 8 females became extremely bloated and died. Thus LHRHa was shown to be the more reliable method of inducing ovulation in the Atlantic croaker. The response interval between hormone treatment and ovulation at different water temperatures was also determined.
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The ultrastructure of spermatogenesis and of the spermatozoon of Acanthopagrus schlegeli (Sparidae) are described. The testis is of the unrestricted type. Germ cells are surrounded by cyst cells. Spermiogenesis involves conspicuous... more
The ultrastructure of spermatogenesis and of the spermatozoon of Acanthopagrus schlegeli (Sparidae) are described. The testis is of the unrestricted type. Germ cells are surrounded by cyst cells. Spermiogenesis involves conspicuous modifications such as intracellular movements (diplosome and mitochondria migration, nuclear rotation, and depression) and structural changes (chromatin condensation, shape of mitochondria, and loss of cytoplasm). The mature spermatozoon has a spherical nucleus with a deep, axial nuclear fossa, and an unusual notch, shaped like a bow tie. The short midpiece contains four spherical mitochondria and encircles the basal body of the flagellum. It is concluded that the A. schlegeli spermatozoon is of a primitive type, but that it is characterized by a unique feature which may provide a useful systematic character.
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ABSTRACT Both transmission- and scanning electron microscopy were used to investigate the fine structure of spermatozoa of the spotted sea bass (Lateolabrax maculatus). The spermatozoa are of the ect-aquasperm type, with a head lacking... more
ABSTRACT Both transmission- and scanning electron microscopy were used to investigate the fine structure of spermatozoa of the spotted sea bass (Lateolabrax maculatus). The spermatozoa are of the ect-aquasperm type, with a head lacking acrosome, midpiece, and tail regions. The centriolar complex is situated outside the nuclear fossa and the flagellum is parallel to the base of the nucleus. A midpiece, containing four mitochondria, extends from the posterior end of the nucleus and encircles the root of the flagellum. A pyramidal basal foot projects laterally at right angles from the midregion of the basal body. The effects of osmolality and pH on activation of spotted sea bass sperm motility were examined and compared with those of the moronids Dicentrarchus labrax and Morone saxatilis. A simple method of cryopreservation semen was also demonstrated. This study contributes to existing knowledge of comparative sperm biology and may facilitate breeding of this economically important species.
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... SS Subramoniam Newton, Cryoprotectant toxicity in penaeid prawn embryos, Cryobiology 33 (1992), pp. 132177. MC Pillai and WH Clark Jr, Hatching envelope formation in shrimp (Sicyonia ingentis) ova:origin and sequential exocytosis of... more
... SS Subramoniam Newton, Cryoprotectant toxicity in penaeid prawn embryos, Cryobiology 33 (1992), pp. 132177. MC Pillai and WH Clark Jr, Hatching envelope formation in shrimp (Sicyonia ingentis) ova:origin and sequential exocytosis of cortical vesicles, Tissue Cell 20 ...
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Several critical variables associated with successful cryopreservation of oyster embryos (Crassostrea gigas) were examined. These were 1) embryo developmental stage, 2) kind and concentration of cryoprotectant, 3) equilibration time, and... more
Several critical variables associated with successful cryopreservation of oyster embryos (Crassostrea gigas) were examined. These were 1) embryo developmental stage, 2) kind and concentration of cryoprotectant, 3) equilibration time, and 4) freezing rate. The percentage of survival was scored as the number of recovered embryos that swam actively 12 h after thawing and had developed into veliger stage. The oyster
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Research Interests: Population Dynamics, Transmission Electron Microscopy, Cryopreservation, Endangered Species, Genetic Diversity, and 15 moreTheriogenology, Biological Sciences, Androgenesis, Hybrid, Animals, Male, Methanol, Fertility Rate, DMA, Genetic variation, Spermatozoa, Sperm Motility, Oncorhynchus, High risk, and Medical and Health Sciences
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... Reports of successful freezing of viable Rainbow Trout (Oncorhynchus mykiss=Salmo gairdneri) eggs to -55ºC (Zell 1978) or to -20ºC (Erdahl and Graham 1980) were subsequently interpreted as supercooling (Harvey and Ashwood-Smith 1982).... more
... Reports of successful freezing of viable Rainbow Trout (Oncorhynchus mykiss=Salmo gairdneri) eggs to -55ºC (Zell 1978) or to -20ºC (Erdahl and Graham 1980) were subsequently interpreted as supercooling (Harvey and Ashwood-Smith 1982). ...
