• Journal of fish pathology
• /
• v.2 no.1
• /
• pp.1-18
• /
• 1989

In Korea, studies on a Nematode, Anguillicola crassa parasitic in the air bladder of eel are not yet reported. This reason led the author to study the parasitic species, state and life history of the A. crassa parasitized in the air bladder of eel in order to take effective control measures against its damage. The size of fully developed eggs was 80 to $92(86.7){\times}62$ to $71(67.4)\;{\mu}m$, larva was 210 to $240(225){\times}18$ to $23(20.6)\;{\mu}m$. The intermediate host of A. crassa was Thermocyclops hyalinus, it was capable for parasitizing the eel after 4 days of invasion and then the size of larva was 360 to $420(390){\times}28$ to $35(31)\;{\mu}m$. Fifty days after eel had ingested the Thermocyclops hyalinus infected with larva of A. crassa, the larvae matured into adult worms in the air bladder of eel. The size of detected adult worms was 7.3 to $31.0(16.5){\times}0.5$ to 2.2(1.2) mm, 4.9 to $13.3(8.3){\times}0.3$ to 0.9(0.4) mm. Investigating the morphology of the worms, they were identified as A. crassa. Monthly the parasitic rate of the worms in the eel was high in June, September and December, but low in January to March. After the investigation on the significance between non-parasitic fish and parasitic fish, it was not significant, therefore it can be considered that there is no effect of infection in the growth of eel. Any abnormality of eels air bladder tissue was not seen by the infection of A. crassa. At 25.0 to $26.7^{\circ}C$ of water temperature the death time of Thermocyclops hyalinus by masoten treatment was 14 hours in 0.5 ppm, 20 hours in 0.4 ppm, 22 hours in 0.3 ppm, 30 hours in 0.2 ppm and 42 hours in 0.1 ppm.

• Proceedings of the KOR-BRONCHOESO Conference
• /
• 1979.05a
• /
• pp.3.2-3
• /
• 1979

Bone conduction loss is one of the most common complication in chronic otitis media, and is mostly high frequency loss. Of 233 tympanomastoidectomy ears, 187 ears were considered eligible for this study. A histopathological change was examined in the natural otitis media of guinea pigs. It is our intention to analyze the pattern of bone conduction loss in chronic otitis media, and to correlate this findings with clinical and pathological changes in human and animal otitis media. l) In unilateral cases, a significant difference in bone conduction threshold was observed between normal and diseased ears, and between each frequency with significant interaction between 2KHz and 4KHz (p 0.01). 2) Using one way analysis of variance, mean bone conduction was compared with the duration of disease. We observed a significant difference (p 0.05) between each group of duration, except between 11-15 and 15-20 years group. 3) A comparison of bone conduction between stapes loss group and intact stapes group revealed significant t ratio (p 0.01) at each frequency. The effect of stapes loss on each frequency was evaluated, using one way analysis of variance. there were significant difference(p 0.05) between 250Hz and 500Hz. and between 2KHz and 4KHz. 4) A comparison of bone conduction between round window obliteration and nonobliteration group revealed significant t ratio (p 0.01) at each frequency. Using one way analysis of variance. the effect of round window obliteration was evaluated in each frequency. We observed significant difference (p 0.05) between 250Hz and 500Hz. and between 2KHz and 4KHz. 5) A comparison of bone conduction between cholesteatoma and non -cholesteatoma group revealed significant t ratio (p 0.01) only in 2KHz and 4KHz. No significant differency was observed in mean bone conduction. 6) In a histopathological study of natural otitis media in guinea pig, we observed inflammatory infiltration of the round window membrane, serofibrinous precipitate in the scala tympani, and degeneration of the organ of Corti most significant near the basal turn. These changes would explain high tone bone conduction loss in the process of chronic otitis media.

• Korean Journal of Agricultural and Forest Meteorology
• /
• v.14 no.4
• /
• pp.254-259
• /
• 2012

Peeling damage of trees is usually caused by Cervidae such as deer, roe deer because of the lack of food in forests. However, it happens as part of the developing of antlers in Jeju Island when the roe deer try to remove the Velvet-the skin of the antlers. The research area is the Hannam experimental forest (400 m up to 500 m above sea level) of Korea Forest Research Institute in Jeju Island, and the survey was carried out along the 6 km long of forest road with 5 m width on both sides. Twenty five tree species (total 267 stands) are damaged by peeling; 18 (134 stands) deciduous broad-leaved species, 5 (71 stands) in evergreen broad-leaved species, 2 (62 stands) coniferous species. The most common damaged species are in order of Daphniphyllum macropodum, Cryptomeria japonica, Lindera erythrocarpa, Clerodendrum trichotomum, Zanthoxylum schinifolium. Mainly damaged trees are approximately 3~4 years old saplings, and they show the mean height $120.7{\pm}42.4cm$, diameter measured at 5 cm height $1.5{\pm}0.5cm$. The Lowest peeling beginning height is $22.1{\pm}10.1cm$, and the mean length of peeling is $27.5{\pm}10.6cm$. Once the peeling damage happens, the saplings are infected by fungi secondly, and are distorted or dead, therefore the future structure of warm-temperate forests could be in influenced in species. Warm-temperate forest landscape and species change related to the climate change is a rising issue in Jeju Island. However the changes caused by peeling damage also could be an important issue in the natural process of forest environment, afforestation, local nursery and sustainable forest management of Jeju Island.

• Korean journal of applied entomology
• /
• v.58 no.3
• /
• pp.183-187
• /
• 2019

To establish the cooperative monitoring network which can investigate introductions or outbreaks of high risk insect pests into Korea, seven universities, Gyeongsang National University, Kunsan National University, Seoul National University, Sunchon National University, Andong National University, Jeju National University, and Chungbuk National University, carried out seven regions' monitoring about nine high risk insect pests, Aceria diospyri, Bactrocera dorsalis, Bactrocera minax, Bactrocera tsuneonis, Cydia pomonella, Lobesia botrana, Proeulia sp., Solenopsis invicta, Stephanitis takeyai, from June to October in 2018. A total of 7,560 traps/visual scouting were investigated in 315 points of 105 local sites of seven regions, resulting the nine species, A. diospyri, B. dorsalis, B. minax, B. tsuneonis, C. pomonella, L. botrana, Proeulia sp., S. invicta, and S. takeyai, were not detected. From this study, we established the nationwide monitoring system which can early detect high risk insect pests and secured a bridgehead for monitoring invasive insect pests passing the border.

• Korean Journal of Environmental Biology
• /
• v.38 no.4
• /
• pp.616-624
• /
• 2020

International trade is one of the primary ways that non-native species spread worldwide. Korea and China are geographically close and have a large mutual trade volume. To investigate the population movement of the invasive whitefly(Bemisia tabaci Gennadius) between the two countries, we compared the biotype distribution, insecticidal response, and the TYLCV(tomato yellow leaf curl virus) viruliferous rate of local populations collected in 2019. Based on the mitochondrial DNA COI sequences of B. tabaci, only the Q biotype was found in all populations in Korea, whereas the B biotype (14.3%) and Q biotype (85.7%) were found in China. In the haplotype composition of the B. tabaci Q biotype, only the Q1 group[Q1H1(79.8%) and Q1H2(20.2%)] was observed in China, but the Q1 group [Q1H1(1.7%) and Q1H2(97.5%)] and the Q2 group(only one individual) were found in Korea. The Korean populations showed high mortality(more than 80%) from 15 commercial insecticides, but the Chinese populations showed significantly low mortality from eight insecticides. No TYLCV infections were observed in the Korean populations while the average TYLCV viruliferous rate was 21.4% in the Chinese populations. Taken together, the results suggest that the population structures of B. tabaci in the two countries are different and may have different immigration histories.

• Journal of Food Hygiene and Safety
• /
• v.36 no.6
• /
• pp.481-487
• /
• 2021

The purpose of this study was to provide safety management information by analyzing the survival and growth-related properties of foodborne pathogens from Romaine lettuce. After cultivating E. coli O157:H7 for 72 h on Romain lettuce via spray inoculation, the bacteria population increased by 2.0 log CFU/g from the initial population, confirming the possibility of survival and multiplication of the pathogen thereon. The study also revealed that there is no significant difference in the cultivation of E.coli O157:H7 after 72 h from inoculation on damaged and undamaged lettuce leaves. As a result of investigating distribution of E.coli O157:H7 on damaged lettuce leaves, it was found that the bacteria is unlikely to adhere on the smooth surface of undamaged leaves and, thus, results in a low population density, whereas the bacteria cluster on the rough surface of damaged leaves and easily enter through the damaged tissues. Furthermore, after 24 h of cultivation of the pathogenic microbe in the extract with concentrations of 10-100%, utilization of the lettuce extract by the pathogen was found to be 8.9 log CFU/mL E. coli O157:H7, 8.6 log CFU/mL L. monocytogenes, and 8.8 log CFU/mL P. carotovorum. The increase in the population of both the pathogenic microbe and foodborne pathogen reached over 4 log CFU/mL, implying the microbe can utilize the lettuce extract as a source of nutrition. Compared to the initial inoculation concentration in 0.1% lettuce extract, the final concentration has increased up to 2.7 log CFU/mL E. coli O157:H7, 1.3 log CFU/mL L. monocytogenes, and 2.9 log CFU/mL P. carotovorum. Accordingly, the study confirms that the minimal growth concentration of the pathogenic microbe is lower than 0.1% and that the pathogen possibly survive and multiply inside the lettuce leaves given the lettuce extract with concentration of 0.1% is consistently supplied through the damaged tissues.

• Journal of Appropriate Technology
• /
• v.6 no.1
• /
• pp.21-27
• /
• 2020

The ASF, which originated in Africa and threatens the world, landed in Asia in 2018 in China, and became a stern threat to the security of the Korean Peninsula when North Korea officially reported the ASF to the OIE in May 2019. In 1921, Montgomery, a British veterinary pathologist, made headlines by naming the African swine fever "African Swine Fever," or ASF, a disease caused by a high fatality virus that existed in East Africa. The ASF, which was a pandemic of endemic diseases in Africa, landed in Portgal around 1957 and swept through farms in Lisbon, Portugal. The ASF continued to settle in Spain and Portugal, causing 40 years of damage until the end of the 1990s, and is now in progress after landing on the Italian island of Sardinia in 1978. The virus, which landed in Portiport of Georgia on the Black Sea coast of the Black Sea in 2007, spread to Russia and caused massive damage to China in 2018, then rapidly spread to Vietnam, Laos and Myanmar in May 2019 and spread across the country, causing massive damage to the pork industry and is now in progress. Just three months after confirming the outbreak in North Korea, the outbreak at farms in Paju and Yeoncheon was confirmed on Sept. 16, 2019, leaving South Korea with the stigma of ASF-causing countries, and although the ASF's nationwide expansion has been blocked, it is currently underway in wild boars. If the ongoing ASF in the two Koreas becomes indigenous, it would be a major disaster not only for the pork industry but also for the Korean Peninsula economy. Under the current circumstances, it is impossible to focus only on veterinary areas limited to South Korea, ruling out risk factors from the ASF outbreak. Currently, it is difficult to prevent damage to the pork industry due to the ASF outbreak due to the poor water defense reality in North Korea, and as it is adjacent to China, which has a high risk of developing various epidemic diseases, there is a need for the two Koreas to jointly conduct quarantine and quarantine on the border areas. First of all, I think rapid exchange of information and education on ASF and other diseases is necessary before establishing a joint defense system on the Korean Peninsula. It is important to conduct thorough quarantine and disinfection of ASF-generated areas in North Korea, and areas bordering China and Russia, and jointly conduct thorough quarantine and control of livestock and livestock products in circulation. Cooperation by the South and North Korean water defense industries to prevent the protracted ASF on the Korean Peninsula by all means and methods is essential.

• Korean Journal of Environment and Ecology
• /
• v.36 no.6
• /
• pp.582-591
• /
• 2022

This study was conducted to eliminate Myocastor coypusMolina, 1782 (Nutria) from Jeju Special Self-Governing Province, South Korea. Habitat identification and eradication were carried out from September to November 2013, and a survey was carried out until June 2022 to check whether the eradication was successful. The habitat was identified with unmanned cameras, interviews, and literature surveys, and the capture was performed using the trapping method with food to attract nutria to the habitat area. The study area for the follow-up survey, which was set relatively wide considering nutria's home range, included wetlands and rivers within 4.0 km² of the habitat area (eradication area). As a result, nutria's habitat was confirmed only at Songdang Ranch, Songdang-ri, of Jeju Island, with traces of habitat (footprints, excrement, and burrows) confirmed in waterways and ponds within the pasture. Eight individuals were captured, including four females, three males, and one individual in too advanced a state of decay to identify the sex. The follow-up survey thoroughly investigated the habitat and its surroundings, focusing on three areas with permanent water, Seongeup Reservoir, Cheonmi Creek, and Molsuni Pond, but no signs of habitat were identified. Therefore, it is determined that nutria inhabiting Jeju Island has been completely eradicated. It is believed that the successful eradication of nutria in the Jeju Special Autonomous Region was possible due to a synergy between 1) the eradication of nutria at the beginning of the settlement phase through rapid capture after confirming the nutria habitat and 2) the delayed expansion period because of rare presence of wetlands, where water is constantly stagnant, on Jeju Island. These results imply that quickly identifying the ecological characteristics of the species and preventing disturbances before they or at the beginning of the ecological disturbance through control and eradication at the initial stage of settlement before the expansion stage is an effective measure to cope with the influx of alien species.

• Korean Journal of Agricultural and Forest Meteorology
• /
• v.25 no.3
• /
• pp.142-150
• /
• 2023

As global warming continues, the time of invasion of Spodoptera frugiperda has been advanced and the inflow rate has been increasing, leading to great increases in damage to crops. In this study, in order to minimize crop damage caused by S. frugiperda, the control period was set for corn fields through control thresholds, and the control effects according to the chemical spraying methods were investigated in forage corn filed. Even under the condition of 4% injury level during the corn silking stage, the damage rate of ear was 70%, showing an aspect of extensive damage. The economic injury level of S. frugiperda second instar larvae was shown to be 0.7 larvae per stalk, and the control threshold level was shown to be 0.6 larvae. The income was calculated by applying the corn wholesale unit price, and according to the result, even under the condition of injury level of 4%, there was a loss of KRW 895,221/10a, and the higher the injury level, the greater the decrease in income. To control S. frugiperda, the insecticidal effects of 10 single formulations registered for S. frugiperda were tested, and according to the results, four types(emamectin benzoate, chlorantraniliprole, indoxacarb, and spinetoram) showed high insecticidal activity not lower than 93.3%, and three types (chloran- traniliprole, spinetoram, and indoxacarb) were considered to be effective in controlling S. frugiperda as they showed high residual effects through insecticidal effect persistence tests. Therefore, conventional control and aerial control were conducted twice at 7-day intervals with indoxacarb SC and chlorantraniliprol WP, which show high activity against S. frugiperda, respectively, prior to the silking of forage corn. As a result, conventional control showed higher control values, 46.3%p in the case of indoxacarb SC and 21.7%p in the case of chlorantraniliprol WP, than aerial control through the primary control. In the secondary control too, higher control values of 26.7%p in the case of indoxacarb SC and 40.4%p in the case of chlorantraniliprol WP were found in conventional control than in aerial control. Therefore, it is considered necessary to prepare measures to improve the control effects in the recent situation where alternative methods for manpower control are widely used.

• Journal of Life Science
• /
• v.34 no.1
• /
• pp.48-58
• /
• 2024

Salmonella is a common food-borne intracellular bacterial pathogen that has triggered significant public health concerns. Salmonella hosts' genetic factors play a pivotal role in determining their susceptibility to the pathogen. Cysteine-rich intestinal protein 1 (CRIP1), a member of LIM/double zinc finger protein family, is widely expressed in humans, such as in the lungs, spleen, and especially the gut. Recently, CRIP1 has been reported as a key marker of several immune disorders; however, the effect of CRIP1 on bacterial infection remains unknown. We aimed to elucidate the relationship between Salmonella infection and CRIP1 gene deficiency, as Salmonella spp. is known to invade the Peyer's patches of the small intestine, where CRIP1 is highly expressed. We found that CRIP1-deficient conditions could not alter the characteristics of bone marrow-derived myeloid cells in terms of phagocytosis on macrophages and the activation of costimulatory molecules on dendritic cells using ex vivo differentiation. Moreover, flow cytometry data showed comparable levels of MHCII⁺CD11b⁺CD11c⁺ dendritic cells and MHCII⁺F4/80⁺CD11b⁺ macrophages between WT and CRIP1 knockout (KO) mice. Interestingly, the basal population of monocytes in the spleen and neutrophils in MLNs is more abundant in a steady state of CRIP1 KO mice than WT mice. Here, we demonstrated that the CRIP1 genetic factor plays dispensable roles in host susceptibility to Salmonella Typhimurium infections and the activation of myeloid cells. In addition, differential immune cell populations without antigen exposure in CRIP1 KO mice suggest that the regulation of CRIP1 expression may be a novel immunotherapeutic approach to various infectious diseases.