• Journal of Photoscience
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• v.9 no.2
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• pp.272-274
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• 2002

The anterior brain vesicle of ascidian larvae contains two distinct pigment cells. Ultrastructure of these pigment cells has been shown that the anterior pigment cell is an otolith for perception of gravity and the posterior pigment cell is an ocellus for light reception. The larva has remarkably simple central nervous system (CNS) composed of about 330 cells. We focused to study neural networks of visual systems. In the present paper, we report the whole structure of the photoreceptors of the ascidian larva visualized by an antibody against arrestin. Visual arrestin is the key protein for the termination of phototransduction and one of the abundant proteins in photoreceptors. Recently, we cloned an arrestin homologue gene, Ci-arr and the expression of Ci-arr was found to be restricted to the photoreceptors in the ocellus. To study the whole structure of the photoreceptors in the larva, we prepared an antibody against Ci-Arr. It is found that anti Ci-Arr antibody specifically stains the photoreceptors, including the cell bodies, the axons, and the nerve terminals. The photoreceptor cell bodies lies in row outside the pigment cup which penetrate the pigment cell and is continuous with the outer segments of the photoreceptor cell, inside the concavity of the pigments. The axons form bundle into a single tract. The tract extends toward the midline, where the nerve terminals diverge and seem to form synapses

• Korean Journal of Ichthyology
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• v.27 no.2
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• pp.133-141
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• 2015

Age and growth of redlip mullet, Chelon haematocheilus were determined using samples collected in Han River estuary of Korea from June, 2013 to May, 2014. Age was determined from sagital otoliths and Annul marks were formed in January once a year. In addition, spawning season was estimated in May, thus first ring was formed 8 months. The mullets were principally composed of 0 to 3 years old and the oldest was 9 years old. Relationship between standard length (SL) and total weight (TW) were $TW=0.0124SL^{3.0133}$($r^2=0.9931$). The Von Bertalanffy growth parameters estimated were $L_{\infty}$ 61.3, $W_{\infty}$ 3,230.6, K 0.29/year, $t_0$ - 0.05 year.

• Animal cells and systems
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• v.13 no.3
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• pp.323-329
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• 2009

We analyzed partial sequences of cytochrome b (cyt-b), a mitochondrial DNA (mtDNA) gene, to determine the genetic relationships between six horsehead fish species: Branchiostegus japonicus, Branchiostegus albus, Branchiostegus auratus, Branchiostegus argentatus, Branchiostegus wardi, and an unidentified Branchiostegus species. The specimens were collected in Korea, China, Japan, and Vietnam. We compared their molecular phylogenetic relationships inferred from mtDNA cyt-b sequences with an osteological analysis. The unidentified species, B. sp., was similar to B. albus in terms of the lack of triangular silver-white dot at the posterior region of eyes (vs. large one present in B. japonicus), but was also similar to B. japonicus in terms of the presence of a straight-shaped first hemal spine (vs. a curve-shaped hemal spine in B. albus). Analysis of the mtDNA cyt-b sequences indicated that the smallest estimated sequence divergence was between the B. japonicus and B. sp. (0.70-0.94%), whereas the largest difference was between B. auratus and B. argentatus (23.06-23.36%). Both the maximum parsimony and maximum likelihood trees showed that the B. sp. was closely clustered with B. japonicus, and that B. auratus was most distant from the other species. When comparing the osteological characters, UPGMA tree showed that the B. japonicus and B. sp. were the most closely clustered species, and B. auratus was the most distantly clustered fish relative to the other species. The shape of the nasal, otolith and first hemal spine was informative for distinguishing B. auratus from the other species. These osteological differences were consistent with the differences in mtDNA.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.26 no.4
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• pp.309-316
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• 1990

Age and growth of the Marbled Sole Limanda Yokohamae in Tokyo Bay were studied by otolith reading of 1,070 fishes from May 1986 to April 1988. Examination of the outer margins of the otoliths showed that the hyaline zone as annulus was formed once a year and that its formation was completed at the end of the spawning season (Feb. to Apr.). Growth of the fish was expressed by the von Bertallinffy's equaion as Lt=255.7{1-exp[-0.505(t-0.149)]} for males and Lt=376.9{1-exp[-0.303(t-0.202)]} for females, where Lt is standard length in mm and t is age in years. It was found that the growth of males and females differs, with the females showing a higher growth than the males at each estimated age. Growth in body weight was also examined. Most of the fish examined were found to be not more than three years old, although the oldest fish were four years old for males and seven years old for females.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.44 no.4
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• pp.312-322
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• 2008

The age and growth of the sandfish, Arctoscopus japonicus were investigated from samples of the eastern sea danish seine and gill net fishery in the East Sea of Korea from February, 2004 to December, 2007. Ages were determined from annuli in otoliths and annuli were formed between December and February once a year. Also, the main spawning period was estimated to be between December and January, thus rings were considered to be annual marks. For the relationship between fork length and total weight, a multiplicative error structure was assumed because variability in growth increased as a function of the length. The relationship between fork length and total weight were $TW=0.0083FL^{3.01}(R^2=0.966)$ for female and $TW=0.0079FL^{3.04}(R^2=0.969)$ for male. The variability in growth was constant as a function of age, revealing an additive error structure. The von Bertalanffy growth parameters estimated by a non-linear method were $L_{\infty}=31.6cm$, K=0.266/year, $t_0=-0.835$ years for female and $L_{\infty}=27.7cm$, K=0.273/year, $t_0=-0.806$ years for male. Growth at age between male and female had a significant difference(P<0.001).

• The Transactions of the Korean Institute of Power Electronics
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• v.7 no.6
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• pp.524-530
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• 2002

A control of the body posture and movement is maintained by the vestibular system, vision, and proprioceptors. Afferent signals from those receptors are transmitted to the vestibular nuclear complex, and the efferent signals from the vestibular nuclear complex control the eye movement and skeletal muscle contract. The postural disturbance caused by loss of the vestibular function results in nausea, vomiting, vertigo and loss of craving for life. The purpose of this study is to develop a off-vertical rotatory system for evaluating the function of semicircular canals and otolith organs, selectively, and visual stimulation system for- stimulation with horizontal, vortical and 3D patterns. The Off-vortical axis rotator is composed of a comportable chair, a DC servo-motor with reducer and a tilting table controlled by PMSM. And a double feedback loop system containing a velocity feedback loop and a position feedback loop is applied to the servo controlled rotatory chair system. Horizontal, vertical, and 3D patterns of the visual stimulation for applying head mounted display are developed. And wireless portable systems for optokinetic stimulation and recording system of the eye movement is also constructed. The gain, phase, and symmetry is obtained from analysis of the eye movement induced by vestibular and visual stimulation. Detailed data were described.

• The Journal of Korean Physical Therapy
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• v.32 no.3
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• pp.152-156
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• 2020

Purpose: The subjective visual vertical (SVV) test is used to evaluate the otolith function in the inner ear. This study compared the different balance ability according to the results of the SVV in healthy adults. Methods: This study recruited 30 normal healthy subjects who did not have neurological and musculoskeletal disorders. The subjects were divided into experimental and control groups based on the results of SVV: experimental group, >2°; control group, <2°. The static balance ability was evaluated using the Fourier Index, which could evaluate the balance capacity objectively and quantitatively. Results: The mean angle of the SVV in the experimental and control groups was 4.44° and 0.59°, respectively. In the result of the Fourier series, the F1 frequency band in the experimental group showed a significantly higher value under one condition compared to the control group (p<0.05). In the F2-4 and F5-6 frequency bands, the experimental group showed a significant increase in the Fourier series value under the four conditions compared to the control group (p<0.05). In the F7-8 frequency band, significantly higher values of the Fourier series were observed in the experimental group under the three different conditions (p<0.05). Conclusion: These results showed increased trunk sway while maintaining static balance in the experimental group who showed a larger SVV angle compared to the control group. The SVV can be applied to evaluate the vestibular system and balance ability in normal adults.

• Fisheries and Aquatic Sciences
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• v.15 no.2
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• pp.169-176
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• 2012

Age and growth of Glyptocephalus stelleri in the East Sea of Korea were determined, from monthly samples of commercial catches, caught by the eastern sea Danish seine fishery in 2007. The annuli of G. stelleri are formed once a year, with the boundary between opaque and translucent zones forming in September. Relationships between total length (TL) and total weight (TW) were $TW=0.002TL^{3.392}$ ($r^2=0.970$) for females and $TW=0.002TL^{3.335}$ ($r^2=0.961$) for males. TLs at annuli formation in otoliths were back-calculated from the otolith-length relationship and were adjusted to von Bertalanffy growth curves to $L_t=39.71(1-{\exp}^{(-0.152(t+1.156))})$ for females and $L_t=32.16(1-{\exp}^{(-0.213(t+0.879))})$ for males. From the age of 3 years, females grew faster than males (P<0.05).

• Korean Journal of Fisheries and Aquatic Sciences
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• v.18 no.3
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• pp.261-265
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• 1985

Limanda yokohamae was studied on its growth, age at maturity, fecundity and survivorship, based on the specimens off the southeastern coast of Korea from December 1983 to November 1984. The total lengths at the formation of annulus on the otolith were back-calculated. The age at the first reproduction is 2yrs in both sexes. Fecundity was estimated to be $121{\times}10^3{\sim}429{\times}10^3$. Annual survival rate is 0.435 in female and 0.335 in male.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.50 no.3
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• pp.278-286
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• 2017

The age and growth of marbled flounder Pseudopleuronectes yokohamae in coastal waters of the East Sea of Korea off Pohang were determined, by evaluating monthly samples of commercial catches, caught by gill nets and longlines from February 2013 to January 2014. New annuli from annually in P. yokohamae otoliths, and the boundary between the opaque and translucent zones forms from March to May. The relationships between total length (TL) and total weight (TW) were $TW=0.009TL^{3.128}$ ($R^2=0.969$) for females and $TW=0.008TL^{3.150}$ ($R^2=0.964$) for males. The TLs at the time of annulus formation, back-calculated from the otolith-length relationship by reference to the von Bertalanffy growth curves, were $L_t=52.63$ ($1-{\exp}^{(-0.231(t+0.033))}$) for females and $L_t=36.22$ ($1-{\exp}^{(-0.400(t+0.117))}$) for males. Commencing at the age of 3 years, females grew faster than males (P<0.05).