• Korean Journal of Ichthyology
• /
• v.19 no.4
• /
• pp.286-291
• /
• 2007

The bitterling, Acheilognathus koreensis spermatozoon has been examined by electron microscopy. The epididymal spermatozoa of A. koreensis are representing typical characteristic of cyprinid spermatozoa including the lateral insertion of flagellum, the organization of centriolar complex in shallow nuclear fossa and the asymmetrical arrangement of mitochondria. The sperm mid-piece contains a large mitochondrion characteristic enclosed by membranous vesicles. The mitochondria aspect is different from that of other cyprinid spermatozoa, which their mitochondria have a conventional aspect and never fuse to form a mitochondrial derivative. In term of sperm evolution, the fused mitochondria are regarded as the apomorphic character in comparison with the separate mitochondria. The single mitochondrion is not found in cyprinid spermatozoon except for Rodeus and Pungtungia.

• Korean Journal of Environmental Biology
• /
• v.22 no.1
• /
• pp.159-166
• /
• 2004

The effects of polychlorinated biphenyls (PCBs) on the reproduction of the oily bitterling, Acheilognathus koreensis were investigated using histological methods. The experimental fishes were exposed to 0. 3.4, 9.3 and 25.8 ${\mu}g\; L^{-1}$ PCBs fey 8 weeks. Dead fishes and abnormal behavior were not observed in control and PCBs exposure group. In compared with control group, PCBs exposure fishes showed differences of gonadal development, gonadosomatic index (GSI), hepatosomatic index (BSI), nuptial color index (NCI) and ovipositor length index (OLI). These results showed that PCBs could disrupt reproductive process in the fish.

• Korean Journal of Ichthyology
• /
• v.18 no.3
• /
• pp.266-272
• /
• 2006

The egg development and early life history of Korean endemic bitterling Rhodeus pseudosericeus were observed under the controlled water temperature, $17.0{\pm}0.5^{\circ}C$. Fertilized eggs are opaque yellow in color, measuring 2.9~3.1 mm in length and 1.6~1.9 mm in breadth. The eggs of this species began to hatch about seventy hours after insemination and the range of total length of larvae were 3.2~3.4 mm. The larvae reached at the heterotrophic stage about twenty-five days after hatching. R. pseudosericeus had a pair of wing-shaped yolk projection during the prelarval stage that is a common character of the genus Rhodeus.

• Journal of Species Research
• /
• v.10 no.1
• /
• pp.1-11
• /
• 2021

Evidence highlighting the importance of gut microbiota in biodiversity conservation is growing; however, gut bacteria in South Korean wildlife have not been well identified. Using a culture-dependent isolation method, we identified the gut bacteria from Korean aquatic wildlife: the gazami crab (Portunus trituberculatus), Korean striped bitterling (Acheilognathus yamatsutae), oily bitterling (Acheilognathus koreensis), leopard mandarin fish (Siniperca scherzeri), Korean dark chub (Zacco koreanus), diving beetle (Cybister lewisianus), spotted steed (Abbottina springeri), and Korean spotted sleeper (Odontobutis obscura interrupta). We identified 18 strains previously unrecorded in South Korea by comparing 16S rRNA gene sequences of isolates against the EzBioCloud and National Institute of Biological Resources(NIBR) databases. The isolated strains belong to the phyla Actinobacteria, Bacteroidetes, Firmicutes, and Proteobacteria. We also assessed for phylogenetic relatedness, Gram-stain reaction, colony and cell morphology, and biochemical characteristics. Basic information and 16S rRNA gene sequences of the isolates were registered in NIBR, and NIBR accession numbers are provided.

• Korean Journal of Ichthyology
• /
• v.17 no.1
• /
• pp.19-28
• /
• 2005

Osteolgical development of Korean striped bitterling, Acheilognathus yamatsutae (Cyprinidae), were investigated using cartilage and bone staining. The parasphenoid, dentary, pterygoid, ceratohyal, branchial arch and parts of the caudal skeleton were formed first as cartilaginous elements at $6.82{\pm}0.08mm$ total length (TL). Formation of frontal, parietal, and maxillary were notable at $7.76{\pm}0.09mm$ TL, and the proximal radial, scapula,and coracoid in the pectoral girdle were developed at this stage. At the same time, the neural and hemal spine were present in the caudal vertebra. The opercle and branchiostegals were observed at $9.68{\pm}0,14mm$, and the posttemporal was formed at $12.9{\pm}40.64mm$ TL, respectively. Ossification in the parasphenoid, pharyngeal bone, dentary, premaxillary, maxillary, and opercle began at about $9.68{\pm}0.14mm$ TL. The cleithrum, supracleithrum, urostyle, and caudal fin were calcified at this stage. The vertebral column was formed and ossified at $11.52{\pm}0.13mm$ TL, and the frontal, preopercle, subopercle, and hyomandibular were ossified at $15.30{\pm}0.68mm$ TL. This fish was late in developing the skeletal formation and ossification as compared with other fishes.

• Korean Journal of Ichthyology
• /
• v.32 no.2
• /
• pp.63-69
• /
• 2020

This study investigated spawning characteristics of Hangang bitterling, Rhodeus pseudosericeus inside the host mussel, Unio douglasiae sinuolatus at the Heukcheon Stream in Korea from April to June 2017. 327 mussels were collected, among them, 34 (14.1%) were spawned mussels of R. pseudosericeus with glochidia. The mean number of R. pseudosericeus embryos with or without glochidia by the mussel gill position was 5.0±3.58 (range, 1~8) vs. 2.8±2.13 (1~9) in the left outer demibranch, 1.5±0.96 (1~3) vs. 1.7±0.82 (1~3) in the left inner demibranch, 1.4±0.51 (1~2) vs. 2.1±1.85 (1~6) in the right inner demibranch, and 6.4±4.82 (1~20) vs. 3.0±1.86 (1~6) in the right outer demibranch. The frequency of R. pseudosericeus embryos with or without glochidia by the mussel gill position was 82.6% vs. 73.4% in the left outer demibranch, 17.4% vs. 9.4% in the left inner demibranch, 26.1% vs. 15.6% in the right inner demibranch, and 58.7% vs. 67.2% in the right outer demibranch. The mean number of R. pseudosericeus embryos with or without glochidia was 8.5±6.43 (1~23) vs. 4.5±3.38 (1~14). The number and frequency of R. pseudosericeus embryos were higher in the mussel with glochidia and the outer demibranchs than those without glochidia and with inner demibranchs.

• Korean Journal of Ichthyology
• /
• v.23 no.1
• /
• pp.10-20
• /
• 2011

Genetic determinant for metallothionein (MT), a cysteine-rich protein playing essential roles in metal detoxification and homeostasis, was characterized in the Korean bitterling (Acheilognathus signifer, Cyprinidae), an endemic fish species. The full-length A. signifer MT (AsMT) cDNA (551 bp) is composed of a single open-reading frame (ORF) to encode a polypeptide of 60 amino acids containing 20 cysteine residues whose positions are conserved in most cypriniform MTs. At the genomic level, the AsMT (2,593 bp spanning the 5'-flanking region to the 3'-untranslated region) represented a conserved tripartite (three exons interrupted by two introns) structure with AT-rich introns. The upstream regulatory region (-1,914 bp from the ATG initiation codon) of AsMT displayed various sites and motifs for transcription factors involved in the metal-mediated regulation and stress/immune responses. The AsMT transcript was ubiquitously detected in various organs with variable expression levels, where the ovary and intestine showed the highest expression, while the heart and skeletal muscle represented the lowest level. During an exposure to copper (immersion in $0.5\;{\mu}M$ Cu for 48 h), the levels of AsMT transcripts were significantly elevated in the liver (more than 3.5-fold), moderately in the gill, kidney, and spleen (ranging from 1.5- to 2.5-fold), and barely in the brain and intestine. Results of this study could form a useful basis to explore the metal-related stress physiology of this endangered fish species.

• Development and Reproduction
• /
• v.20 no.4
• /
• pp.289-296
• /
• 2016

This report describes the sex differentiation of the Korean rose bitterling, Rhodeus uyekii, from hatching to 170 days post-hatch (DPH) in relation to total length (TL), body weight (BW), and integral water temperature (IWT). The growth curve of TL from just hatching to 83 DPH was $5.144e^{0.045t}$ ($R^2=0.961$; t, time), and that of BW was $2.398e^{0.086t}$ ($R^2=0.725$). Primordial germ cells (PGCs) were observed at 17 DPH (7.9 mm TL, 3.74 mg BW, $374^{\circ}C$ IWT), and thereafter began to protrude into the peritoneal cavity. At 21 DPH ($9.2{\pm}0.14mm$ TL, $4.8{\pm}0.07mg$ BW, $462^{\circ}C$ IWT), some PGCs contained condensed chromatin and oocyte were observed in meiotic prophase. In contrast to the ovaries, which grew gradually after sexual differentiation, testes began multiplying at 25 DPH (10.1 mm TL, 5.42 mg BW, $550^{\circ}C$ IWT), when testicular differentiation was first identified, and multiplied continuously thereafter. At 33 DPH (11.2 mm TL, 10.5 mg BW, $726^{\circ}C$ IWT), the developing testes contained spermatogonia that exhibited mitotic activity. No spermatocyte or sperm cell was observed until 83 DPH (18.9 TL, 48.2 mg BW, $1,826^{\circ}C$ IWT). At 170 DPH (32.5 mm TL, 270.1 mg BW, $3,740^{\circ}C$ IWT), which was the end point of this study, the mature ovaries showed germinal vesicle breakdown, while the mature testes contained observable spermatocytes and sperm cells. These results allow us to identify the sex differentiation type of the Korean rose bitterling as differentiated gonochoristic.

• Korean Journal of Ichthyology
• /
• v.18 no.3
• /
• pp.170-177
• /
• 2006

Morphology and distribution of the minute tubercles projected on the skin surface of larvae with its development was observed in the Korean bitterling, Acheilognathus koreensis, known as an endemic freshwater fish. The epidermis of the larvae consisted of a thin single layer, having smaller basophilic flat or round-flattened basal cells. In between the single cell layer, two or three layers were added and they consisted mainly of large epidermal cells just above basal cells. These large unicellular epidermal cells were mainly scale-shaped and rarely cone-shaped, and do not give any histochemical tests for mucosubstances. They were present in anterior region and most region of yolk sac. Whereas, vestigial epidermal cells were distributed in the body region and the caudal fin-fold region. These two kinds of epidermal cells, called minute tubercles, increased in number and height from Just to 8 days after hatching, but as the larvae develop gradually, they became to reduce. At 31days after hatching of free swimming stage and absolute absorption stage of the yolk sac, the minute tubercles did not exist on the whole skin of the larvae.

• Korean Journal of Ichthyology
• /
• v.26 no.2
• /
• pp.83-88
• /
• 2014

An endemic Korean bitterling, Acheilognathus signifer, known as using freshwater mussels for its spawning activity, much prefers Lamprotula leai in Dalcheon stream (Goesan population) and Unio douglasiae sinuolatus in Gadaecheon (Danyang population) stream, Korea. The spawning pattern between two mussels and one bitterling was carried out in two populations from April to June, 2011 and 2013. L. leai in the Goesan population was bigger shell length and have more eggs, larvae or both with A. signifer than those of U. d. sinuolatus in the Danyang population. Also, A. signifer in the Goesan population appeared to have a longer ovipositor and lay ripen eggs more than those of A. signifer in the Danyang population. Glochidium, a larval stage, of some L. leai in the Goesan population was incubated in all the demibranch, whereas for all of U. d. sinuolatus in the Danyang population was found in the outer demibranch only. For L. leai in the Goesan population, the eggs, larvae or both of A. signifer were much more in the non-breeding mussels (giving no glochidium) than the breeding mussels having the glochidium. For U. d. sinuolatus in the Danyang population, in contrast, the non-breeding mussels have fewer eggs, larvae or both less than the breeding one.