• The Korean Journal of Malacology
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• v.7 no.1
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• pp.76-86
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• 1991

A scanning electron microscopic stuey on the glochidial encystment study on the golchidal encystment and excystment of Anodonta fukudai on Acheilognathus yamatsutae, a common natural hostfish, was conducted. The glochidium easily attached to the unscaled surfaces of the host fish such as the fins, lips, and the wall of the buccal cavity. For this study, the fins infected with the glochidia wer mainly observed in a series. The process of encystment was slowly progressed, for 21-25 hours for the early cyst and for 2-4 days for the thick walled cyst. The process of excystmint was visually detected on the 12th day since the attachmint was occurred. The first visible sign was a little tear of the cyst wall covering the hinge and marginal zones of the juvenile clam and once the little sign was appeared the progress of emerging and dettachmint of the juvenile clam from the host was finished relatively in short time. During the process of the encystmint, the cells participationg in covering the attached glochidirm were seened mainly supplied by migration from the surroundings. the shapes of the cells migrating and covering the glochidium were considerably changed and the surface structures of the cells lost their normal pattern of the surface ridges. The unstable forms of the cells were observed almost all throughout the period of the glochidial attachment. No cells of the host epithelium, which were still attached to the juvenile clam energing from the cyst, were observed. The most juvenile clams escaped from the cysts were a little bigger than the glochidia and they were still possessed of the golchidial hooks even though much degenerated. The first growth line was appeared on the shell valves of the juvenild clam when observed right after dettachment.

• Journal of Environmental Science International
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• v.18 no.10
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• pp.1171-1179
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• 2009

The solitary ascidian, Halocynthia aurantium, which is commonly called the sea peach because of its coloration and general shape, is a valuable organism of benthic marine population in the northern region of the East Sea, Korea. It is seldom found at a depth of less than 10 meters and the sea peach is frequently observed in large populations between 20 and 100 meters. It appears to prefer attachment to vertical rocks faces and artificial cement blocks exposed to the currents. Mass mortality and reduction of resources in sea peach, H. aurantium, were occurred in the benthic area of the northern region of the East Sea because of the rapid fluctuation of environmental factors such as temperature and salinity due to mass rainfall in summer and going up north of a strong warm current in winter. Therefore, we examined the effects of temperature and salinity on embryonic development of fertilized eggs, tadpole larva to metamorphosis, and attachment to siphon development. Laboratory-raised larvae were studied using a two-factorial experimental design with four levels of temperature(8, 12, 16 and $20^{\circ}C$) and four levels of salinity(20, 25, 30 and 34 psu). The ascidian larvae of H. aurantium survived environmental conditions between temperature of $8{\sim}20^{\circ}C$ and salinity of 25~34 psu and exhibited positive growth at $8{\sim}16^{\circ}C$ and 30~34 psu. Fertilized eggs have not developed at lower salinity of 20 psu irrespective of temperature range tested and have showed an abnormal development at the salinity of 25 psu between higher temperatures of 20 and $24^{\circ}C$. This result suggests that temperature increase and salinity reduction depending on environmental fluctuation may have significant impacts on population variation of H. aurantium in the northern region of the East Sea.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.34 no.6
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• pp.577-583
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• 2001

The digestive enzyme activities such as $\alpha-amylase$, trypsin and pepsin from the laboratory-reared river puffer Takifugu obscurus were measured from the time course of 1 day until the 65 day after hatching. In the case of $\alpha-amylase$, it was showed minimum activity of 0.0493 U/mg at the total length (TL) 10 mm, and showed maximum activity of 0.1480 U/mg at 19 mmTL. Trypsin and pepsin were showed their maximum activities of 0.0264, 0.0258 U/mg and 0.0178, 0.0201 U/mg when the total length of 16 and 24 mm, and represented remarkable correlations between the changes of enzyme activity and growth rate. The ontogenetic variations of digestive enzymes were represented clearly different patterns; i.e, the pepsin showed higher activity when the periods of larva ($4\~5\;mmTL$) and juvenile II ($19\~24\;mmTL$), however, the trypsin represented maximum activity at the stages of juvenile I ($11\~16\;mmTL$) and young fish (27 mmTL), respectively.

• Korean Journal of Environmental Biology
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• v.32 no.1
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• pp.68-74
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• 2014

Scientific study has investigated the body condition differences by habitat characteristics in larvae Korea salamander (Hynobius leechii) from March to April in 2012. To examine the sensitivity of external environment (predation risk), we divided two groups according to habitat characteristic; 1) Permanent pond and 2) Temporary pond. Howere, each larva was measured by head width at the level of the eye (HWE), largest head width (LHW) and snout-vent length, and we calculated the ratio of the head size by dividing HWE/LHW. As a result, larvae were larger in permanent pond group, had a faster growth rate than in temporary pond group. When exposed to the predator, larvae in permanent pond were smaller HWE/LHW than larvae in permanent pond. Therefore, these results indicate larvae in temporary pond more sensitive to the external environment.

• Journal of Nutrition and Health
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• v.54 no.4
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• pp.342-354
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• 2021

Purpose: Obesity is a serious public health issue for the modern society and is considered a chronic health hazard. There are many surgical and pharmacological approaches to treat obesity. However, various potentially hazardous side effects remain the biggest challenge. Therefore, diets based on foods derived from natural products have gained increasing attention compared to anti-obesity drugs. Recently, research on edible insects as a food source has been a topic of considerable interest in the scientific communities. This study examined the anti-obesity effects of ingesting an edible insect by feeding a high-fat diet (HFD)-induced obese mouse models with a diet containing Tenebrio molitor larvae powder (TMLP). Methods: Six-week-old female C57BL/6J mice were divided into 4 groups according to treatment: 100% normal diet (ND), 100% HFD (HFD), HFD 99% + TMLP 1% (TMLP), and HFD 97% + TMLP 3% (TMLP 3%). TMLP was added to the HFD for 6 weeks for the latter two groups. Results: Compared to the HFD group, mice in the TMLP group showed weight loss, and micro-computed tomographic imaging revealed that the volume of the adipose tissue in the abdominal area also showed significant reduction. After an autopsy, the fat weight was found to be significantly reduced in the TMLP group compared to the HFD group. In addition, the degree of fat cell deposition in the liver tissue and the size of the adipocytes significantly decreased in the TMLP group. Reverse transcription polymerase chain reaction analysis for the mRNA expression of adipogenesis-related genes namely CCAAT-enhancer-binding proteins (C/EBP-β, C/EBP-δ), and fatty acid-binding protein 4 (FABP4) showed that the expression levels of these genes were significantly reduced in the TMLP group compared to the HFD group. Serum leptin level also decreased significantly in the TMLP group in the comparison with the HFD group. In addition, total cholesterol, triglyceride, and glucose levels in mouse serum also decreased in the TMLP group. Conclusion: Taken together, our results showed that TMLP effectively inhibited adipocyte growth and reduced body weight in obese mice.

• Korean Journal of Ichthyology
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• v.35 no.1
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• pp.1-9
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• 2023

The morphological development of larvae and juvenile of Sebastes taczanowskii were studied. The S. taczanowskii were caught at Goseong-gun, Gangwon-do from March in 2016. Larvae beared at water temperature of 11~12℃ (mean 11.5±0.5℃). The just beared larvae were 5.25~5.96 mm (mean 5.60±0.19 mm, n=30) in total length and their mouth and anus were already opened. They began to eat rotifer and transformed to postlarvae stage. 35 days after bearing postlarvae was measured 7.16~11.4 mm (mean 9.02±1.00 mm) in total length and the tip of notochord was bent upward. 48 days after bearing juvenile was measured 9.45~18.7 mm (mean 14.4±1.75 mm) in total length with dorsal fin rays XIII, 13~15; anal fin rays III, 6~8; caudal fin rays 16.

• Journal of Sericultural and Entomological Science
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• v.9
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• pp.27-34
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• 1969

This study was conducted investigate the effect of Gibberellin and Urea on the growth of mulberry tree with the compound treatment, and the characteristic of silkworm when the mulberry leaves simply treated with GB and the compound treatment with GB and Urea were supplied. The results are as follows. 1. Mulberry tree A. The leaf weight per mulberry tree with the compound treatment of GB+ Urea was heavier in spring silkworm and the leaf yield was increased by 7% compared with the non-treatment plot. B. The growth of wattle, leaf length and leaf width was more accelerated in the compound treatment plot of GB+Urea, the single treatment plot of GB and Urea than th!: non-treatment plot in autumn silkworm, and there was observed an incredse yielding effect of 16% in GB+Urea plot, in 16% GB plot and 18% in Urea plot respectively as compared with th: non-treatment plot, hut yield per l000m unit of wattle length was the least in GB plot. C. In the composition of mulberry leaves of treatment, water and crude protein was increased in the compound treatment plot of GB + Urea and the single treatment plot of GB and Urea than the non-treatment plot, but dry matter and carbohydrate were decredsed. 2. Characteristics of Larva in spring silkworm A. The mortality ratio of 4 and 5 instar plot was equally high in the compound treatment plot of GB+ Urea and the pupation ratio of 4 instar plot was lower than other treatment plot. B. Although there was no significant difference observed in the cocoon weight of 10.000 1st-day worms in both 4 and 5 instar plots between each treatment plot, the single treatment plot of GB showed somewhat great than other treatment plots. C. There was no significant difference observed in the cocoon layer ratio between each treatment plot, but 4 instar plots was slightly higher than 5 instar plots. 3. Characteristics of Larva in Autumn silkworm A. The mortality ratio of the compound treatment plot of GB+ Urea and GB was higher than that of the nontreatment and single treatment plot of Urea. B. The pupation ratio of the single treatment plot of Urea was higher than that of the compound treatment plot of GB + Urea, and there was no significant difference observed between other treatment plot. C. The cocoon weight of 10.000 1st-day th instar worms was heavier in the single treatment plot of Urea than nontreatment plot, GB+Urea plot and GB plot. D. The cocoon layer ratio was no significant difference observed between each-treatment.

• Journal of Sericultural and Entomological Science
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• v.16 no.2
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• pp.119-125
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• 1974

When the nomal silkworms reached active time of 3rd instar stage both non-moulting larva and normal silkworms from the same rearing tray were collected and fixed. The silkworms in 4th instar stage whose growth was as dwarfish as those in 1st and 2nd instar stages were also collected and fix with the normal silkworms. Non-moulting larva and normal silkworms were morphologically compared and the examined results from the tissue inspection are summarized as follows： 1. In spite of the fact that the normal silkworms reached the active eating time of 3rd instar stage non-moulting silkworms were dwarfish as if they had been reared for two days. Non-moulting silkworms which were observed at the time of 4th instar stage showed no much difference in their growth. 2. There was the tendency that the exuvial gland as was shown in Fig. 1 and 2 was flat cyslidium of ellipse and its size at thorax was small shile the gland at abdomen was big. 3. The exuvial gland at thorax has been reported to be bigger at thoracic base than at dorsal vessel but according to the present it was examined to be irregular. 4. The size of exuvial gland of silkworms in the active eating stage of 3rd instar was from 151.3${\mu}$ (major axis) to 94.5${\mu}$ (minor axis) at prothorax and from 568.6${\mu}$ (major axis) to 495.1${\mu}$ (minor axis) at 7th abdominal segment. The sire oe exuvial gland of non-moulting silkworm was 57.5${\mu}$ (major axis) to 51.3${\mu}$ (minor axis) at prothorax and from 91.5${\mu}$ (major axis) to 75.5${\mu}$ (minor axis) at 5th abdominal segment (see Fig. 1) 5. When the normal silkworms reached 4th instar active eating stage its exuvial gland was compared to that of dwarfish silkworm. The result was that the size of normal silkworm at prothorax was from 252.2${\mu}$ (major axis) to 131.6${\mu}$ (minor axis) and the size of exuvial gland at 7th abdominal segment was from 691.5${\mu}$ (major axis) to 493.4${\mu}$ (minor axis) while the sire of exuvial gland of non-moulting at prothorax was from 71.4${\mu}$ (major axis) to 61.5${\mu}$ (minor axis) and the size of the non-moulting silkworm's 8th abdominal segment was from 94.6${\mu}$ (major axis) to 71.5${\mu}$ (minor axis) (See Table 2) 6. There was a remarkable difference in the from of exuvial gland of non-moulting silkworm. The size of alveolar of the non-moulting silkworm was many times larger compared to that of normal silkworm 7. There was no great difference between secretory cells of normal and non-moulting silkworms but the granular type exuvial gland was small in sire compared to that of normal silkworm.

• The Korean Journal of Malacology
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• v.21 no.2 s.34
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• pp.107-111
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• 2005

In the present study, the fecundation and fertilization behaviors of the trumpet shell, Charonia fampas sauliae were observed from November 2003 to March 2004. Female has multiple fecundation and multiple fertilization, and the fertilization continued for two days. The fertilized female stayed with the egg mass to protect the eggs, and the fecundation was made during the fertilization. The highest survival rate of egg capsule was 60% at $15^{\circ}C$. Charonia lampas sauliae fed with Chaetoceros calcitrans, Isochysis galbana, and Pavlova lutheri. Growth and survival rates of C. lampas sauliae in the conditions of various water temperature were observed. The highest survival rate was 23% at $15^{\circ}C$ reared for 60 days. The growth was presented in the $15^{\circ}C$ group, with shell length from $408{\pm}21.52{\mu}m\;to\;625{\pm}19.76{\mu}m$ during the experiment.

• Korean journal of applied entomology
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• v.42 no.1
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• pp.53-56
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• 2003

Development and reproduction of the rice armyworm, Pseudaletia separata Walker, were investigated under different temperatures (13, 15, 18, 20, 25, 30, and 33$^{\circ}C$ ). It took 80.6 days to grow from egg to pre-adult at 15$^{\circ}C$, and 27.3 days at 30$^{\circ}C$ (3.0 times shorter growth period compared with that at 30$^{\circ}C$ ). The range of developmental temperature of rice armywom was 15-30$^{\circ}C$. Survival rate from hatched larva to pre-adult was the highest as 70.6% at 25$^{\circ}C$. Pre-oviposition period and the adult longevity were 4.2 and 12.3 days at 15$^{\circ}C$, and 2.9 and 8.0 days at 30$^{\circ}C$, respectively. The highest average fecundity per female was 816.6 at 25$^{\circ}C$. The net reproductive rate (R$\_$o/) and intrinsic rate of natural increase (r$\_$m/) were the highest at 25$^{\circ}C$ as 913.0 and 0.175, respectively. As a result, it was considered that optimum of temperature for P. separata growth was = 25.0$^{\circ}C$.