• Journal of Aquaculture
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• v.20 no.4
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• pp.248-254
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• 2007

Representative cDNA libraries were constructed from various tissue sources of Hemibarbus mylodon, an endangered freshwater fish species in Korea, for the mining of expressed sequence tags (ESTs). Randomized and non-normalized EST analysis was performed with 7 unidirectional cDNA libraries generated from brain, intestine, kidney, liver, muscle, ovary or testis. Of 3,383 ESTs in total, the number of singleton was 2,029, and 333 contigs containing 1,354 ESTs were assembled (percent of unigene = 70.0%). Abundantly expressed gene transcripts and broad clustering of putative gene function were tissue-specific in general, and the redundancy was also variable among those libraries. Over half of H. mylodon ESTs were matched with orthologues from other teleosts among which zebrafish gene sequences were the most frequent in those matches. This initial setting of EST libraries achieved in the present study would be a fundamental basis for the banking of gene resources from this endangered fish species.

• Journal of Veterinary Clinics
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• v.25 no.4
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• pp.307-309
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• 2008

The metacercariae species have often been isolated from fresh water fish in Korea. In this study, we reported Clinostomum complanatum, a species of metacercariae isolated from gill and muscle of Korean barbel (Hemibarbus mylodon), a natural monument fresh water fish in Korea, by morphological observation. The excysted metacercariae, tongue-shaped and progenetic, were 3.11-4.62 mm in length and 0.90-1.43 mm in width. Fresh water fishes are known as the second intermediate hosts of C. complanatum. This is the first isolation report from Korean barbel.

• Journal of Aquaculture
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• v.21 no.3
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• pp.196-200
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• 2008

Korean spotted barbel Hemibarbus mylodon, is an endangered and endemic freshwater species in the Korean peninsula. Amplified fragment length polymorphism (AFLP) was used to analyze the genetic diversity and population genetic structure of three populations (Bukhan, Namhan and Imjin-river). Fifteen AFLP primer pairs produced 795 products of which 135 were polymorphic(17%). Percentages of polymorphic bands were similar among the three populations, with accounting 11.9%, 11.1%, and 13.4% for Bukhan, Namhan and Imjin-river populations, respectively. An average genetic similarity among the three populations was 0.969. The average heterozygosity (0.033-0.040) and genetic diversity (0.036-0.043) were significantly low. Pairwise distance and fixation index analyses of three populations also suggested quite a low genetic differentiation one another. These results would provide a fundamental baseline data to develop the effective strategy for the management and restoration of this endangered fish species.

• Journal of Aquaculture
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• v.21 no.4
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• pp.259-264
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• 2008

Cytogenetic characteristics of three Hemibarbus species (H. labeo, H. longirostris and H. mylodon) were analyzed based on erythrocyte measurement, flow cytometric estimation of cellular DNA content, and karyological analysis. Average nuclear volumes for H. labeo, H. longirostris and H. mylodon were 22.5, 21.7 and $26.0\;{\mu}m^3$, respectively. The estimated genome sizes of those three species were not significantly different from one another, being recorded as 2.51, 2.33 and 2.35 pg/cell for H. labeo, H. longirostris and H. mylodon, respectively. Modal chromosome numbers of the three species were the same as 2n = 50. However, their karyotypes and fundamental numbers (FN) were different among species; 16M+16SM+18T/A (FN = 82) for H. labeo, 18M+16SM+16T/A (FN = 84) for H. longirostris and 18M+24SM+8T/A (FN = 92) for H. mylodon.

• Korean Journal of Ecology and Environment
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• v.40 no.4
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• pp.489-494
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• 2007

Transcriptional modulation of metallothionein (MT) during acute metal exposures (cadmium, copper or zinc) was examined in fry of Hemibarbus mylodon, a threatened fish species in Korean peninsula. Viability of H. mylodon fry was most affected by copper exposure (up to 79% of mortality at 1 ppm for 48 hours) and considerably by cadmium exposure (21 to 54% of mortality). On the other hand, Zn showed the least adverse effect on the viability (0 to 13% of mortality) of this species. Based on the semi-quantitative RT-PCR analysis, the stimulation of MT mRNA in response to metal exposures followed generally in a dose-dependent fashion where cadmium was the most potent inducer for the induction of MT transcripts in fry (up to more than 5-fold) while the lowest response was observed in zinc-exposed group (2-fold at maximum). From the exposure using environmentally realistic doses of cadmium (0 to 0.05 ppm for 24 hours), MT expression at mRNA level was also sensitively modulated toward upregulation up to more than 3-fold as relative to non-exposed control. Results from the present study would be a good basis for understanding the adaptive capacity and stress physiology of this endangered fish species during metal pollution.

• Journal of Aquaculture
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• v.22 no.1
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• pp.83-91
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• 2009

The Korean doty barbel Hemibarbus mylodon (Cypriniformes; Cyprinidae) is a critically endangered freshwater fish species mainly because of its natural habitat degradation. Three full-length complementary DNA (cDNA) clones representing different muscle actin isoforms were isolated and characterized. The three muscle actin isoforms were 1,294-1,601 bp long with the identical open reading frames of 1,134 bp with the deduced amino acid residues of 377. They showed 83.9-87.2% identities in the coding nucleotide level and 96.8-98.1% identities in the amino acid level. Phylogenetic analysis with the coding nucleotide sequences revealed that three muscle actin isoforms of H. mylodon formed strongly supported monophyletic groups with one of cypriniform skeletal $\alpha$-actin (acta1), cypriniform aortic $\alpha$-actins (acta2), and uncharacterized Danio rerio muscle actin isoform/Salmo trutta slow muscle actin (a novel muscle actin type). Our phylogenetic tree further suggested that cypriniform acta2 only showed the orthologous relationship to tetrapod acta2. Other multiple actin isoforms from diverse teleostean taxa were however clustered to no tetrapod orthologs, i.e., acta1, cardiac $\alpha$-actins (aetc1), acta2, and enteric $\gamma$-actin (actg2). This result strongly suggested that teleostean muscle actins have experienced different and complicated evolutionary history in comparison to mammalian counterparts.

• Korean Journal of Ichthyology
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• v.29 no.2
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• pp.101-108
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• 2017

Egg development and early life history of the Korean natural monument fish Hemibarbus mylodon (Pisces: Cyprinidae) were investigated to provide basic data on biological characteristics and ecological recovery. Adult fish were collected from nature and transferred to the laboratory. For the first time, artificial maturation of females and males succeeded after 15 months of indoor culture. Mature eggs and sperm were obtained using Ovaprim injections (0.5 mL/kg) and then the eggs were fertilized using the dry method in the laboratory. The mature eggs were adhesive, turbid, and greyish; they averaged $2.21{\pm}0.06mm$ (n=30) in diameter. The embryos began to hatch about 78 h after fertilization at a water temperature $20{\pm}1^{\circ}C$, and the newly-hatched larvae were $6.6{\pm}0.75mm$ in total length (TL). At 14 days after hatching, the post-larval individuals were $13.5{\pm}0.23mm$ (TL), and their yolk sacs were completely absorbed. Twenty one days after hatching, they entered the juvenile stage and reached $13.5{\pm}0.23mm$ (TL). At 100 days after hatching, their band patterns, external form, and a pair of barbels were similar to those of adults, and they averaged $33.0{\pm}4.25mm$ (TL). The breeding technology and characteristics of early life history obtained in this study will be very helpful for conservation of H. mylodon in nature.

• Fisheries and Aquatic Sciences
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• v.14 no.1
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• pp.43-54
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• 2011

Gene structure of copper/zinc-superoxide dismutase (Cu/Zn-SOD; sod1) was characterized in Hemibarbus mylodon (Teleostei; Cypriniformes), an endangered freshwater fish species in Korean peninsula. Full-length cDNA of H. mylodon SOD1 consisted of a 796-bp open reading frame sequence encoding 154 amino acids, and the deduced polypeptide sequence shared high sequence homology with other orthologs, particularly with regard to metal-coordinating ligands. Genomic structure of the H. mylodon sod1 gene (hmsod1; 1,911 bp from the ATG start codon to the stop codon) was typical quinquepartite (i.e., five exons interrupted by four introns); the lengths of the exons were similar among species belonging to various taxonomic positions. The molecular phylogeny inferred from sod1 genes in the teleost lineage was in accordance with the conventional taxonomic assumptions. 5'-flanking upstream region of hmsod1, obtained using the genome walking method, contained typical TATA and CAAT boxes. It also showed various transcription factor binding motifs that may be potentially involved in stress/immune response (e.g., sites for activating proteins or nuclear factor kappa B) or metabolism of xenobiotic compounds (e.g., xenobiotic response element; XRE). The hmsod1 transcripts were ubiquitously detected among tissues, with the liver and spleen showing the highest and lowest expression, respectively. An experimental challenge with Edwardsiella tarda revealed significant upregulation of the hmsod1 in kidney (4.3-fold) and spleen (3.1-fold), based on a real-time RT-PCR assay. Information on the molecular characteristics of this key antioxidant enzyme gene could be a useful basis for a biomarker-based assay to understand cellular stresses in this endangered fish species.

• Fisheries and Aquatic Sciences
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• v.12 no.3
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• pp.179-184
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• 2009

Hemibarbus mylodon (Cypriniformes) is an endemic freshwater fish species in the Korean peninsula, for which urgent conservation efforts are needed. To understand their stress responses in relation to metal toxicity and thermal elevation, we performed a real-time RT-PCR-based expression assay of hepatic copper/zinc-superoxide dismutase (Cu/Zn-SOD), a key antioxidant enzyme, in response to experimental heavy metal exposure or heat treatment. The transcription of hepatic Cu/Zn-SOD was differentially modulated by acute exposure to Cu, cadmium (Cd), or Zn. Exposure to each metal at $5{\mu}M$ for 24 h revealed that Cu stimulated the mRNA expression of Cu/Zn-SOD to a greater extent than the other two heavy metals. The elevation in Cu/Zn-SOD transcripts in response to Cu exposure was dose-dependent (0.5 to $5{\mu}M$). Time course analysis of Cu/Zn-SOD expression in response to Cd exposure ($5{\mu}M$) revealed a transient pattern up to day 7. Exposure to thermal stress (an increase from 22 to $30^{\circ}C$ at a rate of $1^{\circ}C/h$ followed by $30^{\circ}C$ for 18 h) did not significantly alter SOD transcription, although heat shock protein 90 kDa (HSP90) transcription was positively correlated with an increase in temperature.

• Korean Journal of Ichthyology
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• v.31 no.2
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• pp.90-100
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• 2019

This study was carried out from March to November, 2013 to investigate the fish community structure and distribution characteristics of Phoxinus phoxinus and Rhynchocypris kumgangensis appearing in Gihwacheon Stream, Pyeongchang. A total of 6 families and 19 species of fish emerged during the survey period. The dominant species were R. kumgangensis (Individuals 44.7%, Biomass 30.2%) and P. phoxinus (Individuals 27.7%, Biomass 15.9%). Endemic species were 10 species including Pseudopungtungia tenuicorpus, Coreoleuciscus splendidus, Hemibarbus mylodon, Gobiobotia brevibarba, Microphysogobio longidorsalis, R. kumgangensis, Zacco koreanus, Korecobitis rotundicaudata, Iksookimis koreensis and Coreoperca herzi. Endogenous species were P. tenuicorpus, G. brevibarba and P. phoxinus. Hemibarbus mylodon was a natural monument. Oncherhynchus mykiss was exotic species and translocated species was Oncorhynchus masou masou. The dominant species, R. kumgangensis, appeared at all survey sites. Except for St.6, the b value was more than 3.0 and the slope of K value showed positive correlation. P. phoxinus appeared in St. 3~St. 6 and St. 3 and St. 4 only showed stable populations.