• Korean journal of applied entomology
• /
• v.33 no.2
• /
• pp.107-113
• /
• 1994

This study is canled for tanonomical investigation of Olibatid mites on landscape plan& As the results, thirteen species of Oribatid mites on the plants are described for the first time from Korea. but the harmfulness caused by the mites is not yet proved The mites are Tuberemoeus singularis Sellnick, Zygoribatulo elongoto Hammer. Scahperemaeus yamashitoi Aoki, Oribatula sakamori Aoki, Camis~a segnis (Hemann), Scheloribates Jatipes (Koch), Oppiella nova (Oudemans), Lauroppia neerlondica (Oudemans), Hemileius sp.. Oripodo sp., Twncopes sp.. and Tectocehpeus sp. etc. Among them, Tuberemaeus singularis and Zygoribotulo elongatn are recorded from Korea for the first time And three lalvae are found out at intestine of one specimen of Tuberemoeus singularrs Sellnick which is collected on Cryptomerio japonica D, in Chep (Seoguipo). Therefore, thls mite seems to be ovoviviparous.

• The Korean Journal of Malacology
• /
• v.31 no.3
• /
• pp.171-178
• /
• 2015

The reproductive ecology of freshwater bivalve, Unio douglasiae in Lake Uiam were examined from March 2014 to February 2015. The gonads distributed in reticular connective tissue, the dioecious clams take an internal fertilization and fertilized eggs are stored in the foster-sack in the gills, then the hatched juveniles are released outside after an ovoviviparous process. The gonad index (GI) began to increase in April, reached the maximum value in July and to decrease in August. The reproductive cycle of U. douglasiae can be divided into five successive stages: multiplicative stage (November to January), growing stage (February to March), mature stage (February to May), spawning stage (April to September), recovery stage (August to December). The spawning periods were from April to September, and the main spawning occurred between April and July. The shell length at 50% group maturity was estimated to be 29.4 mm.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.28 no.3
• /
• pp.338-346
• /
• 1995

Studies on activities of hepatocytes and changes of protein and total RNA contents in liver and muscle tissues associated with the gonadal maturation were performed using the adult rockfish, Sebastes schlegeli collected monthly from the adjacent waters at Poryong, Chungnam, Korea. Hepatosomatic index (HSI) of female increased from September and reached the maximum value (2.58) in February (growing stage of ovary). HSI of male began to increase from October (early maturation stage) and revealed the maximum value (3.20) in April (recovery stage). During the period of yolk formation in oocyte, the amount of glycogen particles and lipids in the hepatocytes of female gradually decreased, but total RNA contents increased. In the hepatocytes of male, a number of lipid droplets remained until the mature stage of testis. With the gonadal development of both sexes, granular endoplasmic reticula (Er) became abundant in the hepatocyte. These Ers might be supposed to have the leading role for the syntheses of protein and vitellogenin in the cytoplasm of the hepatocytes. Protein and total RNA contents in the liver and muscle tissues of female began to increase from January (growing stage) and reached the maximum value in early April (maturation stage), and then decreased in late April (gestation stage). In male, their contents began to increase from October (early maturation stage), thereafter reached the maximum value in December (maturation and copulation stage), and decreased in January (degeneration stage).

• The Korean Journal of Malacology
• /
• v.23 no.1
• /
• pp.39-49
• /
• 2007

We investigated to understand the differences in the karyotypes and the reproductive characteristics between the diploid clam, Corbicula japonica in the brackish water and the triploid clam, C. fluminea in the freshwater. The number of chromosomes of the diploid C. japonica were 38, which can be grouped into 19 pairs of two homologues. These can be divided into 11 pairs of telocentric, 4 pairs of subtelocentric, 3 pairs of submetacentric and one pair of metacentric chromosomes. C. japonica is oviparous and dioecious. The clam has two pairs of gills, with the inner and outer-demibranchs, however, they do not act mainly as marsupia. External fertilization occurs in the brackish water. The triploid marsh clam, C. fluminea has 54 chromosomes, which can be grouped into 18 sets of three homologues. These 18 sets can be divided into one metacentric group, five submetacentric groups and 12 subtelo- or telocentric groups. C. fluminea is ovoviviparous and functional hermaphrodite. The triploid condition may be closely related to hermaphroditism. This species has the inner-demibranchs acting mainly as marsupia. The depletion of ripe eggs occurred in the inner-demibranchs of the gill during the incubatory periods, and ripe eggs produced in the hermaphroditic follicles in the gonad during the non-incubatory periods. The gonad developmental stages of two marsh clams (C. japonica and C. fluminea) can be divided into five stages: early active stage, late active stage, ripe stage, partially spawned stages, and spent/inactive stage.

• Korean journal of applied entomology
• /
• v.54 no.4
• /
• pp.393-400
• /
• 2015

An insect parasitic mite was found on a larva from Japanese apricot seed. The mite was identified as Pyemotes moseri Yu et Liang (Acarina: Pyemotidae) new to Korea. The host larva was identified as Eurytoma maslovskii using mitochondrial DNA sequencing analysis. We conducted preliminary study on its reproduction and parasitization capacity in laboratory condition. A mated female mite reared on Eurytoma maslovskii larva. We counted and sexed newborn progenies and then eliminated them during periodical observations. To test parasitization capacity, a PCR tube containing mass reared P. moseri and Japanese apricot seeds (assumed bear larva of E. maslovskii) placed in a stainless bath filled with potting soil. One month later, we surveyed the seeds whether the E. maslovskii larva parasitized by mite or not. We repeated this experiment three times with five replications each. Average life span (days from parasitization to the end of reproduction) of gravid females was 24.4 days (n=8). A gravid female reproduced 104.0 female progenies (n=8). Although there were more than seven Japanese apricot seeds per bath containing larva or pupa, we found parasitization only in two seeds.

• Development and Reproduction
• /
• v.4 no.2
• /
• pp.175-180
• /
• 2000

The reproductive cycle of ovoviviparous melania snail, Semisulcospira libeytina libertina was studied in the valley near Naewon Temple in Yangsan, Korea. Water temperature (WT) of the habitat ranged from 1.3$^{\circ}C$ to 22.5$^{\circ}C$ The meat weight rate (MWR) reached the maximum with the beginning of WT increase in March and the minimum in August. Monthly changes in average oocyte diameter showed the maximum (249.6$\pm$2.6 ${\mu}{\textrm}{m}$) in July and the minimum (134.3$\pm$2.8 ${\mu}{\textrm}{m}$) in December S. libertina libertina seemed to be a year-round breeder except for mid-summer and mid-winter. Two main reproductive cycle of the species could be divided into five successive stages: multiplicative (March, October), growing (April and May, November), mature (June and July, December), ovulation (August, January), parturition (September and October, March to May) and resting (September, February) stages in female and multiplicative (March, October), growing (April, November), mature (March to June, December), copulatory (July and August, January), resting (September, February) stages in male.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.29 no.1
• /
• pp.26-34
• /
• 1996

Copulation process, fertilization and gestation of the viviparous teleost surfperch, Ditrema temmincki were investigated by using photomicroscopy. Samples were collected from the vicinity of Suyoung Bay, Pusan, Korea from May 1992 to August 1993. During the copulation period, the copulatory organs were protruded at the base part of right and left soft ray of the anal fin in mature male. Secondary sexual characteristics index (SSCI) of male participated in copulation was above 3.5. Mature oocytes appeared only in the female containing sperms in the ovarian cavity. Transport of the spermatozoa into the ovarian cavity during copulation belonged to a spermatophore type. After copulation, spermatozoa remained in the ovarian cavity for about one month untill fertilization. Fertilization occured within the follicular cavity. Fertilized eggs were released into the ovarian cavity where they developed during gestation period. Developmental sequence of the female was as following: fertilization-ovulation-hatching-parturition. Right before parturition, the total length (TL) of the embryo was about 63.0 mm. When TL of maternal body was 20.0 cm, the mean numbers of the embryo were 18. The numbers of the embryo were positively related to the maternal body size.

• Journal of Aquaculture
• /
• v.8 no.1
• /
• pp.31-46
• /
• 1995

Gonadal maturation and annual reproductive cycle in ovoviviparous oblong rockfish, Sebastes oblangus on the basis of monthly gonadosomatic indices (GSI), hepatosomatic indices (HSI) and histological observations of gonadal tissues. GSI values of female were in a wide range from $0.l5\pm0.0l\;(July)\;to\;58.54\pm3.86$ (December) and began to increase in August and reached the maxium in December, then decreased rapidly thereafter. Male GSI values were in a range from $0.08\pm0.03$ (July) to $1.55\pm0.27$ (September) and began to increase rapidly in July and reached the maximum in September, then decreased gradually, thereafter. Female HSI was in a range from $0.89\pm0.12$ (December) to $3.73\pm0.15$ (October), and male's was from $2.09\pm0.76$ (October) to $3.62\pm0.48$ (August). HSI reached the maximum values one or two months before GSI reached their maxium values in both sex, and then decreased rapidly thereafter. Mature oocytes began to appear in late October as being oocytes began to mature in August, and the type of oocyte development is categorized in the roup-synchronous oocyte development'. Ovulation and fertilization of ripe oocytes occurred in November, and hatched larvae were born from December to January. Maturation of testis was progressed in short term from August to October and spermatozoa were released in October. Sperm balls consisted of many spermatozoa were preserved in ovarian cavity of female after copulation. These results may suggest that the annual reproductive cycle of oblong rockfish could be divided into the following successive stages: growing (August and September), mature (September and October), gestation (November and December), parturition (December and January) and resting (February to July) in female, and growing (August and September), mature (September and October), copulation (October) and resting (November to July) in male.

• The Korean Journal of Malacology
• /
• v.30 no.2
• /
• pp.107-116
• /
• 2014

Gonadal development and maturation mechanism were studied on the freshwater marsh clam Corbicula papyracea (Heude), which is the endangered species in Korea. The specimens were collected in the rearing ponds and waterway of NFRDI in Gapyeong-gun, Gyeonggi-do from January to December 2004, and then investigated by condition factor, relative growth, gonadal development phases and gonad histological characters based on 30-50 individuals every month. Comparing with the freshwater marsh clam, C. papyracea is small, light olive brown shell and violet interior. The hermaphrodite individuals of C. papyracea take an internal fertilization and fertilized eggs are stored in the foster-sack in the gills, then the hatched juveniles are released outside after an ovoviviparous process. The average water temperature of inhabit area was in range of $1.8-27.0^{\circ}C$ and usually took great effects on the gonad maturation of C. papyracea. The condition factor ranged from 0.14 to 0.21 throughout the year, which was the lowest during winter season (December-February), and gradually increased to the highest value of 0.21 in May. The ratio of meat weight to total weight was 25.9-38.7%, indicating the similar trend with condition factor. The highest values of condition factor and the ratio of meat weight appeared 1-2 months later than gonadosomatic index reached the peak value, it was probably because that the ovoviviparous eggs would spend a long period before hatching from the foster-sack in the gills. To synthesize the characters of meat weight, condition factor and gonad development by histological study, reproductive cycle of C. papyracea could be divided into five successive stages: multiplicative stage (December to February), growing stage (February to May), mature stage (June to August), spawning stage (August to November), recovery stage (November to December). The smallest shell length of matured C. papyracea was 12.6 mm, and individuals, larger than 16 mm, was formed the nursery in the gills.

• Journal of Life Science
• /
• v.28 no.9
• /
• pp.1076-1080
• /
• 2018

Carrageenan (CGN) has been used as a safe food additive for several decades. CGN has also been widely used to induce inflammation in various animal models. Likewise, degraded CGN (dCGN), which is produced by subjecting CGN to acid hydrolysis, also induces inflammation and does so more effectively than CGN. One of the most important characteristics of an immunological adjuvant is its ability to activate innate immunity. The immune-adjuvant effects of CGN and dCGN have not yet been studied in detail. The purpose of this study was to evaluate the immunological adjuvant activities of both CGN and dCGN, which was done by comparing the levels of an ovalbumin (OVA)-specific antibody after treatment with OVA in the absence or presence of CGN or dCGN in plasma from immunized mice. CGN and dCGN showed similar levels of adjuvant activity, as evidenced by increased antibody titer. Specifically, both CGN and dCGN significantly increased the levels of OVA-specific IgG, IgG1, and IgG2a antibodies in the plasma as compared with OVA alone (the control). However, compared to the positive control (Freund's adjuvant), both CGN and dCGN caused greater increases in IgG1 than in IgG2a. These results suggest that CGN and dCGN have similar adjuvant activities and produce more IgG1 antibodies than IgG2a.