• Journal of Aquaculture
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• v.20 no.2
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• pp.75-80
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• 2007

Amino acid composition and relationship of the commercially valuable five Korean Veneridae, Protothaca jedoensis, Ruditapes philippinarum, Meretrix lusoria, Saxidomus purpuratus and Cyclina sinensis were compared. The major amino acids of five species in Veveridae clams were ureanine, taurine, proline, glycine, alanine and arginine. A similarity of amino acid between C. sinensis and M. lusoria was highest (0.94) and lowest (0.52) for between C. sinensis and P. jedoensis, respectively.

• Development and Reproduction
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• v.14 no.4
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• pp.269-279
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• 2010

Some characteristics of germ cell differntiations and the function of accessory cells during spermatogenesis, and mature sperm ultrastructure in male Protothaca (N.) jedoensis were investigated by transmission electron microscope observations. The morphology of the spermatozoa of this species has a primitive type and is similar to those of other species in the subclass Heterodonta. Accessory cells, which are connected to adjacent germ cells, are involved in the supplying of the nutrients for germ cell development. The morphologies of the sperm nucleus and the acrosome of this species are the cylindrical type and cap shape, respectively. Spermatozoa are approximately $46{\sim}50{\mu}m$ in length including a long sperm nucleus (about $2.44{\mu}m$ in length), an acrosome (about $0.45{\mu}m$ in length), and tail flagellum (about $42{\sim}46{\mu}m$). The axoneme of the sperm tail shows a 9+2 structure. As some characteristics of the acrosomal vesicle structures, the basal and lateral parts of basal rings show electron opaque part (region), while the anterior apex part of the acrosomal vesicle shows electron lucent part (region). These characteristics of the acrosomal vesicle were found in the family Veneridae and other several families in the subclass Heterodonta. These common characteristics of the acrosomal vesicle in the subclass Heterodonta can be used for phylogenetic and systematic analysis as a taxonomic key or a significant tool. The number of mitochondria in the midpiece of the sperm of this species are four, as one of common characteristics appear in most species in the family Veneridae and other families in the subclass Heterodonta. However, exceptionally, only three species in Veneridae of the subclass Heterodonta contain 5 mitochondria. The number of mitochondria in the sperm midpiece can be used for the taxonomic analysis of the family or superfamily levels as a systematic key or an important tool.

• Journal of the korean society of oceanography
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• v.31 no.3
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• pp.117-122
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• 1996

Oxygen consumption by the Manila clam, Ruditapes philippinarum (Bivalvia: Veneridae) maintained in a culture tank for 7-10 weeks was measured with an automatic intermittent-flow-respirometer (AIFR). There was evidence for an endogenous tidal rhythm of 12.4 h in oxygen consumption, at irregular intervals of between about 7 and 18 hours during experiments of between 22 h 5 min and 70 h 32 min (duration) recording for fasting animals in constant darkness at constant temperatures in the absence of tidal rhythms.

• The Korean Journal of Malacology
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• v.12 no.1
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• pp.53-83
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• 1996

러시아 블라디부스톡에 위치한 극동대학 동물박물관 소장 이매패류의 목록과 주석을 기재하였다. 총 71과 520종을 기재하였는데 그 중 종의 수가 많은 과는 Arcidae, Cardiidae, Tellinidae, Unionidae, Mytilidae, Veneridae, Ostreidae, Pectinidae, and Asartidae등이다. 각 종은 lot와 표본 숫자와 함께 채집기를 기재하였으며, 모식종(type specimen)은 사진과 기재 일자 및 박물관 소장번호를 기재하였다.

• The Korean Journal of Malacology
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• v.32 no.1
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• pp.17-23
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• 2016

Ultrastructural studies of oocyte development and vitellogenesis associated with the follicle cells in female Phacosoma japonicus were investigated by electron microscope observations. Vitelloogenesis in the oocytes occured by way of endogenous autosynthesis and exogenous heterosynthesis: vitellogenesis occurred through a process of endogenous autosynthesis, which involves a combined activity of the Golgi complex, rough endoplasmic reticulum, and mitochondria. However, the process of exogenous heterosynthesis involved endocytotic incorporation of extraovarian precursors into the basal region of the early vitellogenic oocytes. In this study, follicle cells, which attached to the previtellogenic and vitellogenic oocytes, were easily found. In particular, the follicle cells were involved in the development of previtellogenic oocytes by the supply of nutrients, and vitellogenesis in the early and late vitellogenic oocytes by endocytosis of yolk precursors. The functions of follicle cells, which attached to mature oocytes, accumulate reserves of lipid granules and glycogen particles for vitellogesis in the cytoplasm of the follicle cells.

• Journal of Aquaculture
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• v.17 no.3
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• pp.197-208
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• 2004

Five commercially valuable Korean Veneroid, Protothaca jedoensis, Ruditapes philippinarum, Saxidomus purpuratus, Cyclina sinensis and Meretrix lusoria were recognized by comparing internal and external morphological characters. As length of the primary tooth was directly grown proportional to shell size but all other characters were not measured according to size of shell. Hence, the morphological characters of these Veneroids may be estimated from the size of the unique primary tooth and it might be enough to be a good criterion for identification of species among Veneriods. Numerical index of hinge plate length of these species was assessed systematically, irrespective of measuring the length, height and width of the shell. The highest internal and external morphological similarity was observed between P. jedoensis and R. philippinarum and the lowest similarity was observed between P. jedoensis and M. lusoria. These similarities may be affected by multiple environmental factors as well as genetic characters. For artificial seed production of P. jedoensis, R. philppinarum, a closest relative among the five species, must be focussed.

• The Korean Journal of Malacology
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• v.10 no.1
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• pp.38-48
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• 1994

Gonadal developmint, age and growth of Ruditapes philippinarum were investigated using samples from the intertidal zone of Simpo on the coast of Kimje, Korea, which were collected onthly for one year from Februaty 1993 to January 1994.Ruditapes philippinarum is diecious in sex. The gonads are located between the subregion of the midintestinal glands and reticular connective tissue of the foot. The ovary is composed of a number of ovarian sacs, and the testis is composed of numerous seminiferous tubules. The clam spawns once a year from early June to darly October, and the main spawning occurred between July and August when the water temperature went above 23$^{\circ}C$. Ripe oocytes are about 65-70${\mu}{\textrm}{m}$ in diameter. Gonadal phases of this species can be divided into five successive stages; multiplicative(February to March), growing (April to May), mature(Aprilto Septimber), spent(June to October), and degenerative and resting(july to March). Spawning is closely related to the sea water temperature. Based on the monthly variations of marginal index (MI')of the shell, it was suggested that the annual ring mark formation occurred in March once a year and took approximately 8 months (0.67 year) for first ring to be formed on the shell. The relationship between the shell length(SL) and the total weight (TW) was represented by nonlinear equation; TW=1.208 x 10/ sup -4/ S $L^{3.158}$, and also in the relationship be-tweenthe shell length (SL) and the shell height(SH), the shell length and the shell width (SW) were represented by the linear equations; SH=0.726 SL-0.483, SW=0.542 SL-0.803.Growth curves for shell length and total weight fitted to von Bertalanffs equation were expressed as: S $L_{t}$ =68.34(1- $e^{0.221}$(t+0.418)) T $W_{t}$ =75.16(1- $e^{0.221}$(t=0.418))$^{3.158/3.158}$

• Development and Reproduction
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• v.18 no.2
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• pp.73-78
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• 2014

This study attempts to propose the possibility of the sex reversal in Sinonovacula constricta and Gomphina veneriformis by confirming the changes in the sex ratio with the shell length in the same population level. For analysis of sex ratio, 100 individuals of S. constricta (SL 26.5-95.0 mm) and 2385 individuals of G. veneriformis (SL 15.1-60.1 mm) were used. Sex was analyzed histologically. Both species displayed the tendency of increase in the female proportion with increase in shell length. In this study, changes in the sex ratio in accordance with the growth of S. constricta and G. veneriformis are determined to be indirect evidence that signifies their sex reversal.

• The Korean Journal of Quaternary Research
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• v.8 no.1
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• pp.33-42
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• 1994

The study area is filled up by alluvium which can be classified into lower and upper beds by the facies of deposits and their degree of weathering. The lower bed is not of marine but of fluvial. The upper bed is mainly composed of clay and silt or fine sand beds col-ored dark or dark gray which are of neritic or brackish yielding mollusca fossils. The oyster(Crassostrea ariakensis) obstained from the depth of 3m below the present sea level in the upper bed was dated at 4,100 110Y.B.P. and the veneridae(Meretrix lamarck) 1m height above the present delta plain in the old sand bar was dated at 1,700 85Y,B,P. It is therfore concluded that the study area a small kern col of terrestri-al basin prior to postglacial age had experienced the Holocene transgression. Consequently the study area is considered to have been progressively formed under neritic or brackish circumstance before 1,700Y.B.P.

• Animal cells and systems
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• v.11 no.2
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• pp.191-198
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• 2007

The ultrastructure of germ cells and follicle cells during oogenesis, oocyte degeneration, reproductive cycle, and first sexual maturity in female Cyclina sinensis were investigated for clams collected from Simpo, Jeollabuk-do, Korea, by cytological and histological observations. Vitellogenesis occured by way of endogeous autosynthesis and exogenous heterosynthesis: vitellogensis occurred through a process of autosynthesis, which involves a combined activities of the Golgi complex, mitochondria, and rough endoplasmic reticulum. The process of heterosynthesis involved endocytotic incorporation of extraovarian precursors into the basal region of the early vitellogenic oocytes prior to the formation of vitelline envelope. The follicle cells appear to play an integral role in vitellogenesis and oocyte degeneration, functioning in phagocytosis and digestion of products originating from the degenerated oocytes: these functions can permit the transfer of yolk precursors needed for vitellogenesis. Follicle cells might have a lysosomal system for breakdown and might also resorb phagosomes in the cytoplasm for nutrient storage during oocyte degeneration.