• Korean journal of applied entomology
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• v.39 no.2
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• pp.117-122
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• 2000

The chemosterilizing effects of 4 benzoylphenylureas (BPUs), were tested on the adult house fly at different developmental stages. The male and female flies before insemination (I-day-old) or with fully developed ovaries (5-day-old) were exposed to the flask surface coated with BPUs solution (300 ppm) for 24 hrs. None of the eggs layed by the 5-day-old flies on the next day of exposure to either flufenoxuron or teflubenzuron hatched to larvae. The eggs layed by the 5-day-old flies exposed to either triflumuron or diflubenzuron also showed a significantly reduced hatchability of 23%. The first egg batches layed by 1-day-old flies exposed to flufenoxuron showed hatchability of only 1%. These results indicate that the BPUs applied were effective in egg sterilization irrespective of developmental stage of house fly. The effect of flufenoxuron was the most pronounced and lasted for 5 days after exposure.

• Parasites, Hosts and Diseases
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• v.53 no.1
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• pp.51-58
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• 2015

Toxocariasis is a soil-transmitted helminthozoonosis due to infection of humans by larvae of Toxocara canis. The disease could produce cognitive and behavioral disturbances especially in children. Meanwhile, in our modern era, the incidence of immunosuppression has been progressively increasing due to increased incidence of malignancy as well as increased use of immunosuppressive agents. The present study aimed at comparing some of the pathological and immunological alterations in the brain of normal and immunosuppressed mice experimentally infected with T. canis. Therefore, 180 Swiss albino mice were divided into 4 groups including normal (control) group, immunocompetent T. canis-infected group, immunosuppressed group (control), and immunosuppressed infected group. Infected mice were subjected to larval counts in the brain, and the brains from all mice were assessed for histopathological changes, astrogliosis, and IL-5 mRNA expression levels in brain tissues. The results showed that under immunosuppression, there were significant increase in brain larval counts, significant enhancement of reactive gliosis, and significant reduction in IL-5 mRNA expression. All these changes were maximal in the chronic stage of infection. In conclusion, the immunopathological alterations in the brains of infected animals were progressive over time, and were exaggerated under the effect of immunosuppression as did the intensity of cerebral infection.

• 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.

• International Journal of Industrial Entomology and Biomaterials
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• v.29 no.2
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• pp.153-161
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• 2014

The aim of this study is to investigate the effects of ambient thermal environments on the development of swallowtail butterflies (Sericinus montela Gray). Developmental durations and survival rates of S. montela were examined at two crucial developmental stages, embryonic and larval development, at varying temperatures ranging from $15^{\circ}C$ to $35^{\circ}C$. As expected, our results indicated that increasing temperatures decreased the developmental duration and survival rate of the eggs. However, the larvae and pupae showed maximum survival rates at $20.0^{\circ}C$ and $25.0^{\circ}C$, and the represented durations were similar to those of the eggs. Larval development was stage-specific, revealing that the fourth and fifth instars at the later stages were more susceptible to temperature variation. When considering both parameters, the optimal development of S. montela occurred within the temperature range of $20.0-25.0^{\circ}C$. The lower threshold for the complete development of S. montela from eggs to eclosion of adults was calculated at $10.6^{\circ}C$ by linear regression analysis. The estimated value is similar to that of other endemic insects distributed in temperate climate zones, which indicates that S. montela belongs to a small group of swallowtails adjusted to low ambient temperatures. From the results, we predict that the full development of S. montela could be achieved within the temperature range of $17.5-30.0^{\circ}C$. Embryonic development ceased at both test temperature extremes, and no further larval development proceeded after the third instar at $35.0^{\circ}C$. These results suggest that embryogenesis can be significantly influenced by slight variations in the ambient thermal environment that fall below the optimal range.

• The Korean Journal of Soil Zoology
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• v.6 no.1_2
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• pp.33-36
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• 2001

This study was carried out to screen 11 peony varieties collected for resistance to northern root-knot nematode, Meloidogyne hapla. The larval population of Meloidogyne halpa to the Uisongjakyak, Taebaekjakyak, Doseo, EP368, EP512 peony were detected high denisties with individuals of 98-173 per 300 ml soil, but Sabeol, Yongsu, Kimchon, Pl23 peony showed low number of larvar with 21-60. The root rot were lowered in Yongsu, Kimchon peony than Uisongjakyak, Taebaekjakyak, EP368, EP512. It seems to involved with densities of 2nd juvernile population in that rot rate of root was increased as increase of 2nd stage larvae. Two peony, Uisongjakyak, Taebaekjakyak were susceptable to M. hapla with high egg mass formation which showed 49,28 in each root. And Yongsu, Doseo, EP368, EP512 were Mid resistance with 1-15 egg mass of each root. Whereas Sabeol, Kimchon, Pl23, EP337, EP425 were found to be resistant to M, hapla with few egg mass formation of 4-7 each root.

• International Journal of Industrial Entomology and Biomaterials
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• v.20 no.2
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• pp.107-114
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• 2010

For stable germline transformation, the promoter of Bombyx mori cytoplasmic actin gene (BmA3) has been used for ubiquitous expression of transgenes. So far, no strong promoter is available for ubiquitous expression in B. mori, excluding BmA3 promoter. To identify more powerful promoter than previously reported BmA3 promoter, we isolated 9 clones that show stronger signal compared to BmA3 by a dot blot hybridization. Among these 9 clones, we focused on one clone which has high amino acid homology (85%) with hypothetical protein 32 gene of Lonomia obliqua. This clone, named bHp32 (B. mori hypothetical protein 32) was ubiquitously expressed in all tissues and developmental stage of fifth instar B. mori larvae. As result of promoter assay using dual luciferase assay system, we found the highest transcription activity region (-1,200/+220) in the 5'-flanking region of bHp32 gene, which has 42-fold more intensive promoter activity than BmA3 promoter. Moreover, the bHp32 promoter was normally regulated in Bm5, Sf9, and S2 cells. Therefore, we suggest that bHp32 promoter may be used more powerful and effectively for transgene expression in various insects containing B. mori as a universal promoter.

• Ocean and Polar Research
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• v.44 no.1
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• pp.39-59
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• 2022

How in the Antarctic icefish, generally, and Pseudochaenichthys georgianus, in particular, otoliths increase in size and build new material as the fish ages and passes through different life phases is largely unexplored. Morphometric details of 3418 otoliths of Ps. georgianus from S. Georgia and 318 from S. Shetland, were processed and proportions of the amounts of collagen and aragonite removed by EDTA were determined for different age groups. Microstructural investigations showed that characteristics of the 3-dimensinal collagen net are the reason for the radial direction and orientation of the aragonite needles of approximately 1.0 ㎛ in length in larval and 2.3 ㎛ in length in adult specimens. Earlier generated increment layers from the primordial centre (PC) in the dorsal direction restrict those of the secondary centre (SC), causing new growth layer accretion in different directions. In the otoliths of larval Ps. georgianus, aragonite layers are 0.89 ㎛ wide while in juveniles and adults they measure 1.45-2.86 ㎛. Otoliths change from a sphere shape in the larvae to a longish object of irregular outline in the older stages. It is tentaively suggested that the observed otolith shape differences at distinct growth stages are due to physical effects related to swimming speeds at particular water depths and locations. To confirm that otoliths, apart from being useful for age analyses, could also serve to establish correlations between developmental stage and the oceanic environment the fish spend time in, further analyses using additional species and state-of-the-art methods like µCT imaging to evaluate otolith volumes and shapes are required.

• Korean journal of applied entomology
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• v.48 no.2
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• pp.237-243
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• 2009

This study was conducted to develop economic injury level (ElL) and economic threshold (ET) of Cabbage armyworm, Mamestra brassicae L. on cabbage (Brassica oleracea L. var). The changes of cabbage biomass and M. brassicae density were investigated after introduction of larval M. brassicae (2nd instar) at different densities: 0, 1, 2, 4, 8, and 16 larvae per plant at 40 d after planting for an open field experiment, and 0, 2, 5, 8 and 12 larvae per plant at 25 d after planting for a glass house experiment. In the field experiment, the yield loss of cabbage was not significantly different among treated-plots at 30 d after the larval introduction, showing an over-compensatory response of cabbage plants to M. brassicae attack. In the glasshouse experiment, however, the biomass of cabbage at 15 d after the larval introduction significantly decreased with increasing the initial introduced number of M. brassicae, resulting in 38.3, 36.7, 21.7, 23.3 and 16.7g in above treated-plots, respectively. The relationship between cumulative insect days (CID) and yield loss (%) of cabbage was well described by a nonlinear logistic equation. Using the estimated equation, ElL of M. brassicae on cabbage was estimated at 44 CID per plant based on the yield loss 14%, which take into account of an empirical gain threshold 5% and marketable rate 91% of cabbage. Also, ET was calculated at 80% of the EIL: 35 CID per plant. Until a more elaborate EIL-model is developed, the present result may be useful for M. brassicae management at early growth stage of cabbage.

• Korean Journal of Ichthyology
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• v.12 no.4
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• pp.236-243
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• 2000

The purpose of present the study was to describe the spawning behavior and early life history of the grass puffer, Takifugu niphobles. The grass puffer was caught at the spawning ground on the coast Dolsan, Korea from May to the 1998. Artificial fertilization was carried out to get fertilied eggs. Spawning season was from the end of May to the beginning of July on the coast of the Dolsan, Korea. Form 2~6 days before the spring tide the aduct males and females began to aggregate in the shore water, and they spawned in the upper part of intertidal zone exposed to air among pebble stone. The fertilized eggs were demersal, transparent and spherical in shape, and its diameter were 0.87~0.95 mm with several oil globules of 0.0014~0.0540 mm. Hatching began about 146 hours after fertilization under water temperature $21.2{\sim}22.3^{\circ}C$. The newly-hatched larva was 2.02~2.24 mm in total length (TL, mean: 2.14 mm), with 22~24(8~9+14~15) myotomes, and mouth and anus was not yet open. In 3 days after hatching it was measured 2.64~2.93 mm in TL (mean: 2.76 mm), and yolk sac was completely absorbed and transformed to postlarval stage. In 15 days after hatching it was measured 4.43~4.82mm in TL (mean: 4.59mm), and the caudal notochord flexion started. The larvae reached the juvenile stage in 28 days after hatching and attained 7.55~7.65mm in TL (mean: 7.60mm), and all fin-rays were formed.

• Korean Journal of Ichthyology
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• v.32 no.3
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• pp.166-181
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• 2020

The egg development, early life history and spawning site characters of Korean endemic fish, Coreoleuciscus splendidus (Gobioninae), were investigated at the part of Jo-jong stream in Korea from May 2020. The fertilized eggs were 2.05~2.23 mm (mean, 2.13 mm) in diameter and had no oil globules. The embryo began to hatching about 98 hrs after fertilization under water temperature of 20±1℃. The newly-hatched larvae were 5.03~5.68 mm (mean, 5.31 mm) in total length (TL), and their mouth and anus were not opened. 4 days after hatching, Several rod-like cupulae were observed on the head and lateral side of the body at 6.95~7.89 mm (mean, 7.51 mm). 7 days after hatching, the post-larva stage were 8.39~9.29 mm (mean, 8.78 mm) in total length, and their york were completely absorbed. The cupulae were completely distinguished. They entered the juvenile stage when all fin-rays were formed at 29 days after hatching, and their TL were 14.16~17.04 mm (mean, 14.99 mm). Squamation was initiated on the caudal body at approximately 18.21~23.74 mm (mean, 30.28 mm), 38 days after hatching, and completed at 26.82~33.33 mm (mean, 19.42 mm), 73 days after hatching, the external characteristics from of juveniles were same to adults. The spawning site was characterized by bottom structure of pebble (64~16 mm) and gravel (16~2 mm), environmental conditions of the spawning sites were 6~18 cm in water depth, 0.43~0.73 m/sec in bottom water velocity. In spawning sites, an egg mass or separated eggs were located a small gap of under the pebble and gravel.