• Korean Journal of Fisheries and Aquatic Sciences
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• v.32 no.1
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• pp.10-17
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• 1999

Feeding Habits of Acanthogobius flavimanus collected from the eelgrass bed in Kwangyang Bay from January to December 1994 were studied. A. flavimanus was a carnivore which consumed mainly polychaetes, crabs, shrimps, gammarid amphipods and fishes. Its diets included small quantities of ophiuroids, gastropods, bivalves, caprellid amphipods, isopods and tanaids. It showed ontogenetic changes in feeding habits. Small individuals fed mainly on polychaetes and amphipods. While the consumption of polychaetes and amphipods decreased with increasing fish sin, the consumption of shrimps, crabs and fishes increased. A. flavimanus fed diverse prey organisms in adult stage. The relative proportion of the major prey items changed with season. Although the consumption of polychaetes, shrimps and gammarid amphipods was relatively high in spring and autumn, A. flavimanus fed various prey organisms in nearly equal proportions in the other seasons.

• Korea-Australia Rheology Journal
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• v.17 no.3
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• pp.117-123
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• 2005

Background: Reduced deformability of red blood cells (RBCs) may play an important role on the pathogenesis of chronic vascular complications of diabetes mellitus. However, available techniques for measuring RBC deformability often require washing process after each measurement, which is not optimal for day­to-day clinical use at point of care. The objectives of the present study are to develop a device and to delineate the correlation of impaired RBC deformability with diabetic nephropathy. Methods: We developed a disposable ektacytometry to measure RBC deformability, which adopted a laser diffraction technique and slit rheometry. The essential features of this design are its simplicity (ease of operation and no moving parts) and a disposable element which is in contact with the blood sample. We studied adult diabetic patients divided into three groups according to diabetic complications. Group I comprised 57 diabetic patients with normal renal function. Group II comprised 26 diabetic patients with chronic renal failure (CRF). Group III consisted of 30 diabetic subjects with end-stage renal disease (ESRD) on hemo-dialysis. According to the renal function for the diabetic groups, matched non-diabetic groups were served as control. Results: We found substantially impaired red blood cell deformability in those with normal renal function (group I) compared to non-diabetic control (P = 0.0005). As renal function decreases, an increased impairment in RBC deformability was found. Diabetic patients with chronic renal failure (group II) when compared to non-diabetic controls (CRF) had an apparently greater impairment in RBC deformability (P = 0.07). The non-diabetic cohort (CRF), on the other hand, manifested significant impairment in red blood cell deformability compared to healthy: control (P = 0.0001). Conclusions: The newly developed slit ektacytometer can measure the RBC deformability with ease and accuracy. In addition, progressive impairment in cell deformability is associated with renal function loss in all patients regardless of the presence or absence of diabetes. In diabetic patients, early impairment in RBC deformability appears in patients with normal renal function.

• Korean Journal of Environmental Biology
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• v.32 no.2
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• pp.153-158
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• 2014

In order to determine the testicular cycle of the Korean brown frog, Rana coreana, the gonadosomatic index (GSI) and the changes of germ cells in testis for adult males were investigated throughout the year. The study indicated that the spermatogenesis in the seminiferous tubule of testis began in August and became most active in the month of September, and the GSI was recorded the highest and the cross area of seminiferous tubule was the widest on this period. Furthermore the seminiferous tubules at the post spawning stage appeared in testis during February, and the spermatogenesis was quiescence period of time from March to July and the GSI and the cross area of seminiferous tubule were found to be the lowest. Based on these observations, we suggest that, GSI of male Korean brown frog changes significantly between July to August, indicating the testicular cycle with discontinuous spermatogenic process, and the breeding season was confirmed to be February.

• Korean Journal Plant Pathology
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• v.1 no.3
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• pp.190-194
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• 1985

The insect vector (Laodelphax striatellus) of rice black-streaked dwarf virus prefered rice plant to maize in feeding both in the cage and in the field, whereas the percent of infectious plants was much higher in maize than rice plants. The causal virus reduced the adult longevity, total number of hatching nymphs and maturity rate from nymphs of the insect vector. The percent of dry weight over fresh weight in rice from early to late growth stages was lower in diseased plants than in healthy plants but it was reversed on maize plant in early growth stage. In agarose gel-diffusion and microprecipitin serological tests, the intensities of antigen with antisera were in orders the preparation partially purified from infected maize leaves> rice stems> rice leaves> maize stems. The pholem galls in diseased plants developed well in the low temperature.

• Molecules and Cells
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• v.25 no.4
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• pp.566-571
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• 2008

Calcineurin (Cn) is a calcium/calmodulin-dependent serine/threonine protein phosphatase that has diverse functions in different cell types and organisms. We screened proteins interacting with the C. elegans CnA homolog, TAX-6, by the yeast two-hybrid system. CNP-3 (Calcineurin interacting protein-3) is a novel protein that physically interacts with the catalytic domain of TAX-6. It is strongly expressed in the nuclei of intestine, hypodermis, dorsal uterine regions and spermatheca. Expression begins around the 60-cell stage and proceeds during all larval stages and the adult. To elucidate the biological function of cnp-3 we isolated a cnp-3 deletion mutant. Since CNP-3 binds CnA, we looked at factors associated with calcineurin loss-of-function mutants, such as brood size, body size, serotonin- and levamisole-mediated egg-laying behavior. The cnp-3(jh145) single mutant had no gross defects compared to wild-type animal. However, the phenotypes of the double mutants, tax-6(p675);cnp-3(jh145) and cnb-1(jh103);cnp-3(jh145), were more severe in terms of brood size, body size and serotonin-mediated egg-laying defects than tax-6(p675) and cnb-1(jh103), respectively. These results suggest that dysfunction of cnp-3 enhances certain calcineurin loss-of-function phenotypes in C. elegans.

• Journal of Sericultural and Entomological Science
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• v.36 no.1
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• pp.69-75
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• 1994

Through the histological and anatomical investigation of silkworm gonad, N. bombycis infection was found to begin from the peripheral region of ovarial sheath or testicular sheath, then, the pathogens spread to the inner portion. Peroral inoculation with purified spores of N. bombycis to 2nd instar larvae at dosages around 106-8/㎤ of artificial diet resulted in the extremely extended larval survival as long as 15 to 22 days of 4th instar. The growth of ovarioles was confirmed in the 10 to 14 day old larvae, oogonia developed into oocytes and nurse cell against heavy infection of the ovary. Gonads rarely obstructed oogenesis and spermatogenesis in the pupae failed in adult eclosion. Light infection of female hosts effected insignificantly on the ovarial development, however, recorded 100% transmission of the pathogens to the progeny populations. Conclusively, ovarial inflection of silkworm induce transovarial transmission begins around 2~3 day old pupae when ovarioles extruded out to hemocoel, and the infection period thought to be continued until the stage of eggs complete shell formation in the ovariole.

• International Journal of Industrial Entomology and Biomaterials
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• v.23 no.1
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• pp.107-113
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• 2011

Infection effect of $Nosema$ $bombyics$ on the midgut of silkworm $Bombyx$ $mori$ and subsequent appearance of spores and the performance of larvae was studied. Autopsy of larvae showed white pustules on the surface of midgut at 5 days of post infection (pi). At later stage, important organs like midgut, silk gland and gonads reduced in size and all these organs showed white pustules. Light microscope observation of pustules revealed enormous spores. Spore multiplication was at a faster rate in young larvae. Infection of the adult larvae resulted in pebrinized pupa and moths. Larval weight, cocoon weight and cocoon shell ratio reduced as the post infection period increased. Transverse sections of midgut showed $N.$ $bombycis$ infection limited to a few columnar cells at 3-5 days of pi. At 7 days pi, cell volume increased, cells were swollen and elongated. Heavily infected cells looked like sacks filled with parasite and the apical region of certain cells were bulging into the gut lumen. Later at 8-9 days of pi, spores or its developing stages leaked into the lumen either freely or enclosed within the globules of host cytoplasm. Besides columnar cells, development of $N.$ $bombycis$ was observed in the regenerative cells and rarely in goblet cells. Development of $N.$ $bombycis$ was also observed in both longitudinal and circular muscles at the late pi period. The histopathological changes, deformities and spore production time in the host were all influenced by the spore dosage and age of the host.

• Korean Journal of Veterinary Service
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• v.39 no.2
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• pp.75-80
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• 2016

Severe fever with thrombocytopenia syndrome (SFTS) is an emerging disease characterized by fever and thrombocytopenia. Haemaphysalis longicornis ticks comprise the major population of ticks in the environment and have been considered as the main vector for SFTS virus (SFTSV). Here we investigated the distribution of ticks carrying SFTSV collected from the environment using the dragging or sweeping methods during April~October 2015 in Jeollanam-do, Korea. Sampling was taken from Songjeong, Omi, Bangkwang, Sandong areas in Jiri walking trails. Among the total 3,869 ticks collected, 3,823 ticks (98.8%) were H. longicornis, 41 (1.1%) were Amblyomma testudinarium, and 5 (0.1%) were Ixodes nipponensis. Classification results by regional groups of H. longicornis indicated that 1,613 ticks were collected in Sandong, 1,190 ticks in Omi, 603 ticks in Bangkwang, and 417 ticks in Songjeong. In monthly distributional studies of H. longicornis based on the developmental stages, nymph (325 ticks) was collected from May to October, 94% of larvae from April to June, and 94% of adult from June to August. These results showed the different dominant stage of ticks according to seasons. However, no SFTSV-specific gene was detected in 3,823 ticks of H. longicornis, 41 of A. testudinarium and 5 of I. nipponensis.

• Reproductive and Developmental Biology
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• v.33 no.4
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• pp.263-271
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• 2009

Cardiovascular diseases (CVDs) are one of the most cause of death around the world and fields of interest for cardiac stem cells. Also, current use of terminally differentiated adult cardiomyocytes for CVDs has limited regenerative capacity therefore any significant cell loss may result in the development of progressive heart failure. Human embryonic stem cells (hESCs) derived from blastocyst-stage embryos spontaneously have ability to differentiate via embryo-like aggregates (endoderm, ectoderm and mesoderm) in vitro into various cell types including cardiomyocyte. However, most effective molecule or optimized condition which can induce cardiac differentiation of hESCs is rarely studied. In this study, we developed both spontaneous and inductive cardiomyocyte-like cells differentiation from hESCs by treatment of induced-factors, 5-azacytidine, BMP-4 and cardiogenol C. On the one hand, spontaneous and inductive cardiomyocyte-like cells showed that cardiac markers are expressed for further analysis by RT-PCR and immunocytochemistry. Interestingly, BMP-4 greatly improved homogeneous population of the cardiomyocyte-like cells from hESCs CHA15 and H09. In conclusion, we verified that spontaneously differentiated cells showed cardiac specific markers which characterize cardiac cells, treated extrinsic factors can manage cellular signals and found that hESCs can undergo differentiation into cardiomyocytes better than spontaneous group. This finding offers an insight into the inductive factor of differentiated cardiomyocytes and provides some helpful information that may offer the potential of cardiomyocytes derived from hESCs using extrinsic factors.

• Korean Journal of Environmental Biology
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• v.37 no.4
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• pp.585-591
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• 2019

Most insect-resistant LMOs have been produced by applying Cry and Vip3Aa proteins. Vip3Aa protein is activated during the vegetative stage of Bacillus thuringensis (Bt) and the inhibitory activity of the Vip3Aa protein against pathogenic attacks from lepidopteran insect species is well known. However, a risk assessment of the Vip3Aa protein compared to the Cry protein has not been conducted in South Korea. This study demonstrates a possible risk assessment method for Vip3Aa protein against honeybees (Apis mellifera). For the risk assessment of the protein, we purified the recombinant Vip3Aa protein in Escherichia coli. The survival rate and symptoms of general intoxication of 4 months honeybees were measured after Vip3Aa exposure. These results indicated that there was no significant difference in the survival rate and the symptom between Vip3Aa and the control buffer. In this study, we established standard methods of Vip3Aa protein purification and oral adult toxicity test using A. mellifera as an LMO risk assessment technique for preserving the natural ecosystem of South Korea.