• Korean Journal of Veterinary Research
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• v.51 no.2
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• pp.123-128
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• 2011

Salmonella spp. is an important pathogen to both public and swine industry. The aim of this study was to investigate the distribution of Salmonella serovar and antibiotics susceptibility of the isolates from Korean swine producing systems. A total of 63 (5.28%) Salmonella spp. was isolated from 1,194 samples (977 fecal materials and 67 organ samples). The predominant Salmonella (S.) enterica serotype and serovar was group B (69.8%) and S. Typhimurium (47.6%), S. Derby (20.6%) and S. Heidelberg (1.6%). But S. Cholerasuis which is characterized host specific by septicemia and enteritis to pigs was not isolated. Antimicrobial susceptibility of the isolates varies as follows: Norfloxacine (75%), Ciprofloxacin (67.5%), Amikacin (60%), Colistin (60%), Enrofloxacin (55%). All of isolates were resistant to Erythromycin, Penicillin, Tetracycline and Lincomycin. The results of this study provided useful information regarding antimicrobial susceptibility and resistance patterns to treat salmonellosis and to prevent emergence of multidrug resistance Salmonella.

• Development and Reproduction
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• v.24 no.4
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• pp.277-285
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• 2020

The disease-causing koi herpes virus (KHV), also known as cyprinid herpesvirus-3 (CyHV3), causes mass mortality of koi and carp. Koi (Cyprinus carpio) is a host for KHV, one of 12 virus species in the Alloherpesviridae family. We examined the effects of KHV disease koi (KK), and on koi×red common carp (KR) and red common carp×koi (RK) cross, using a virus challenge test. The infected fish had clinical signs that included gill necrosis and skin lesions. The RK and KR were highly more resistant (cumulative mortality: RK; 6% and KR; 8%) to KHV infection than KK fish (cumulative mortality: 28%). KHV DNA was confirmed in the tissues of all dead fish in groups by use of polymerase chain reaction (PCR), and the presence of the KHV protein in kidney was confirmed by immunohistochemistry. Histological analysis showed severe gill lesions and fusion of the lamellae in KK fish, but less severe damage in RK fish. In immunohistochemistry analysis, the KHV protein localized in the cytoplasm of infected kidney cells of KK, but the cross groups had lower levels of KHV antigen. Our data indicate that the cross groups had increased resistance to KHV disease.

• The Plant Pathology Journal
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• v.35 no.1
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• pp.1-10
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• 2019

Wheat blast occurred in Bangladesh for the first time in Asia in 2016. It is caused by a fungal pathogen, Magnaporthe oryzae Triticum (MoT) pathotype. In this review, we focused on the current status of the wheat blast in regard to host, pathogen, and environment. Despite the many efforts to control the disease, it expanded to neighboring regions including India, the world's second largest wheat producer. However, the disease occurrence has definitely decreased in quantity, because of many farmers chose to grow alternate crops according to the government's directions. Bangladesh government planned to introduce blast resistant cultivars but knowledges about genetics of resistance is limited. The genome analyses of the pathogen population revealed that the isolates caused wheat blast in Bangladesh are genetically close to a South American lineage of Magnaporthe oryzae. Understanding the genomes of virulent strains would be important to find target resistance genes for wheat breeding. Although the drier winter weather in Bangladesh was not favorable for development of wheat blast before, recent global warming and climate change are posing an increasing risk of disease development. Bangladesh outbreak in 2016 was likely to be facilitated by an extraordinary warm and humid weather in the affected districts before the harvest season. Coordinated international collaboration and steady financial supports are needed to mitigate the fearsome wheat blast in South Asia before it becomes a catastrophe.

• The Korean Journal of Food & Health Convergence
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• v.9 no.2
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• pp.1-6
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• 2023

As oil palm trees are an important economic source in many countries, particularly in Southeast Asia and Africa, the study of Ganoderma boninense is crucial for the sustainability of the oil palm industry. This study aims to understand the biology and ecology of the fungus, its pathogenesis, and the impact it has on oil palm trees. This knowledge can be used to develop management strategies to mitigate the damage caused by the fungus, such as the use of resistant varieties, chemical and biological control methods, and cultural practices. This study is to ensure the long-term productivity and sustainability of the oil palm industry. The main method of recent academic studies on this pathogen is molecular biology, with a focus on genetic analysis and functional genomics. Researchers have used techniques such as PCR, DNA sequencing, and transcriptomics to identify genes and pathways involved in pathogenesis and better understand the fungus's interactions with its host plant. Other methods used in recent studies include biochemical analysis, microscopy, and phytohormonal assays to investigate the biochemistry and physiology of the interaction between G. boninense and oil palm. This study is intended to provide implications from a new perspective by organizing and integrating studies on Ganoderma boninense.

• Journal of Veterinary Science
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• v.24 no.3
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• pp.42.1-42.6
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• 2023

Lumpy skin disease (LSD) is one of the most important emerging transboundary diseases. Recently, LSD has emerged in many countries in the northern hemisphere. The LSD virus has a huge genome and is highly resistant to environmental conditions. The virus is also host-specific and large ruminants, such as cattle and domestic water buffalo, are particularly susceptible. In addition, wild ruminants can serve as potential reservoirs for spreading the LSD virus. The emergence might be related to climate change in various regions because LSD is an arthropod-borne infectious disease. This disease causes enormous economic losses, such as leather damage, decreased milk production, abortion, and death in infected ruminants. The economic importance of LSD in the bovine industry has forced countries to develop and implement control strategies against the disease. With the recent global spread and the economic impact, LSD will be discussed intensively. In addition, effective preventive measures are suggested based on the presence or absence of LSD outbreaks.

• The Plant Pathology Journal
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• v.40 no.5
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• pp.537-550
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• 2024

Pectobacterium is a major bacterial causal agent leading to soft rot disease in host plants. With the Arabidopsis-Pectobacterium pathosystem, we investigated the function of an Arabidopsis thaliana WRKY55 during defense responses to Pectobacterium carotovorum ssp. carotovorum (Pcc). Pcc-infection specifically induced WRKY55 gene expression. The overexpression of WRKY55 was resistant to the Pcc infection, while wrky55 knockout plants compromised the defense responses against Pcc. WRKY55 expression was mediated via Arabidopsis COI1-dependent signaling pathway showing that WRKY55 can contribute to the gene expression of jasmonic acid-mediated defense marker genes such as PDF1.2 and LOX2. WRKY55 physically interacts with Arabidopsis ORA59 facilitating the expression of PDF1.2. Our results suggest that WRKY55 can function as a positive regulator for resistance against Pcc in Arabidopsis.

• Korean Journal of Veterinary Research
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• v.11 no.1
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• pp.1-39
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• 1971

The purpose of present study was to investigate the possibility to immunize guineapigs and swine against Metastrongylus apri infection by the administration of irradiated infective larvae. Four main experiments were undertaken. Firstly, three groups of infective larvae irradiated at $3{\times}10^4r$, $4{\times}10^4r$, and $5{\times}10^4r$ respectively were inoculated to guineapigs and their immunogenic effects were examined from the clinical, anatomical, and serological viewpoints to decide the optimal dose of X-ray for the atenuation of them. Secondly, the migratory behavior of the larvae irradiated at the optimal dose was compared with that of normal infective larvae. Thirdly, pigs were inoculated with each 5,000 infective larvae irradiated at the optimal dose and the clinical, anatomical and serological responses of them before and after challenge were examined. Fourthly, the heated extract of adult M. apri which had been used as an antigen in the serological examinations was analyzed and compared with that of adult Ascaris suis and of adult Trichuris suis by immunoelectrophoretic method. The results obtained are summerized as follows: 1) The optimal dose of X-ray for the atenuation of the infective larvae which can minimize the pathogenecity but keep the antigenecity of the infective larvae was $5{\times}10^4r$. 2) Guineapigs could become completely resistant to subsequent challenge infection by the administration of 1,000 infective larvae irradiated at $5{\times}10^4r$, without showing any symptom of disease before and after the challenge. 3) There were some indication that guineapigs could acquire complete immunity after they overcome the infection with normal infective larvae. 4) It was shown that, in guineapigs, the $5{\times}10^4r$-irradiated larvae can migrate to the large intestine and mesenteric lymph node within a day, where they stay for as long as 16 days to stimulate the host's immunity. 5) It also was shown that, in guineapigs, the normal infective larvae challenged to resistant guineapigs can migrate to the large intestine and mesenteric lymph node, where they are affected by the immune mechanism of host within 10 days without further migration. 6) Pigs could become partially resistant to subsequant challenge by the administration of 5,000 infective larve irradiated at $5{\times}10^4r$; no clinical symptom occurred after the administration, but milder symptoms of parasitic bronchitis were observable after the challenge infection and fewer number of worms were detected from the lungs at autopsy compared with severe symptoms and much number of worms in control pigs. 7) It was shown that, in pigs, a few of the $5{\times}10^4r$-irradiated larvae can migrate to the lungs, where they stay for as long as 104 days in stunted and sterile states; their body-lengths were short and their uteri developted no eggs. 8) There was evidence that the male larvae were more susceptible to X-ray than the female larvae. 9) Antibodies relating to the administration with $5{\times}10^4r$-irradiated or normal larvae were detected from the sera of both guineapigs and pigs by means of indirect haemagglutination and agar diffusion precipitin tests. Relatively higher antibody titers were recorded by the former test, but precipitin bands were demonstrable only when the positive sera were concentrated in one tenth of original volume in the later one. 10) The antibody titers of pig sera began to rose on 14 days, kept their peak during the period from 14 th day to 21st day, and fell to a low level on 28 days after the administration of $5{\times}10^4r$ or normal infective larvae. 11) A slight increase in gamma globublin of the pig sera occurred following the administration. The gamma globulin level showed a tendency to fluctuate in acordance with the antibody level. 12) A marked eosionophilia occurred in pigs on 7 or 14 days following the administration. The eosinophil count showed the same tendency to fluctuate as the gamma globulin did. 13) It was shown that the serum antibodies detected by the heated extract of adult Metastrongylus apri react crossly with the heated extract of adult Ascaris suis but not with that of adult Trichuris suis in indirect haemagglutination and agar diffusion preciption reactions. 14) The heated extract of adult Metastrongylus apri could he divided into 9 antigenic components by immunoelectrophoresis, one (arc 4) of which was shown to be common to both extracts of adult Ascaris suis and adult Trichuris suis, and the other one (arc 9) to only the extract of adult Ascaris suis.

• Korean journal of applied entomology
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• v.48 no.2
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• pp.123-158
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• 2009

An attempt was made to stimulate future research by providing exemplary information, which would integrate published knowledge to solve specific pest problem caused by resistance. This review was directed to find a way for delaying resistance development with consideration of chemical(s) nature, of mixture, rotation, or mosaics, and of insecticide(s) compatible with the biological agents in integrated pest management (IPM). The application frequency, related to the resistance development, was influenced by insecticide activity from potentiation, residual period, and the vulnerability to resistance development of chemical, with secondary pest. Chemical affected feeding, locomotion, flight, mating, and predator avoidance. Insecticides with negative cross-resistance by the difference of target sites and mode of action would be adapted to mixture, rotation and mosaic. Mixtures for delaying resistance depend on each component killing very high percentage of the insects, considering allele dominance, cross-resistance, and immigration and fitness disadvantage. Potential disadvantages associated with mixtures include disruption of biological control, resistance in secondary pests, selecting very resistant population, and extending cross-resistance range. The rotation would use insecticides in high and low doses, or with different metabolic mechanisms. Mosaic apply insecticides to the different sectors of a grid for highly mobile insects, spray unrelated insecticides to sedentary aphids in different areas, or mix plots of insecticide-treated and untreated rows. On the evolution of pest resistance, selectivity and resistance of parasitoids and predator decreased the number of generations in which pesticide treatment is required and they could be complementary to refuges from pesticides To enhance the viability of parasitoids, the terms on the insecticides selectivity and factors affecting to the selectivity in field were examined. For establishment of resistant parasitoid, migration, survivorship, refuge, alternative pesticides were considered. To use parasitoids under the pressure of pesticides, resistant or tolerant parasitoids were tested, collected, and/or selected. A parasitoid parasitized more successfully in the susceptible host than the resistant. Factors affecting to selective toxicity of predator are mixing mineral oil, application method, insecticide contaminated prey, trait of individual insecticide, sub-lethal doses, and the developmental stage of predators. To improve the predator/prey ratio in field, application time, method, and formulation of pesticide, reducing dose rate, using mulches and weeds, multicropping and managing of surroundings are suggested. Plant resistance, predator activity, selective insect growth regulator, and alternative prey positively contributed to the increase of the ratio. Using selective insecticides or insecticide resistant predator controlled its phytophagous prey mites, kept them below an economic level, increased yield, and reduced the spray number and fruits damaged.

• Parasites, Hosts and Diseases
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• v.50 no.1
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• pp.7-13
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• 2012

$Toxoplasma$ $gondii$ can modulate host cell gene expression; however, determining gene expression levels in intermediate hosts after $T.$ $gondii$ infection is not known much. We selected 5 genes ($ALDH1A2$, $BEX2$, $CCL3$, $EGR2$ and $PLAU$) and compared the mRNA expression levels in the spleen, liver, lung and small intestine of genetically different mice infected with $T.$ $gondii$. ALDH1A2 mRNA expressions of both mouse strains were markedly increased at day 1-4 postinfection (PI) and then decreased, and its expressions in the spleen and lung were significantly higher in C57BL/6 mice than those of BALB/c mice. BEX2 and CCR3 mRNA expressions of both mouse strains were significantly increased from day 7 PI and peaked at day 15-30 PI ($P$<0.05), especially high in the spleen liver or small intestine of C57BL/6 mice. EGR2 and PLAU mRNA expressions of both mouse strains were significantly increased after infection, especially high in the spleen and liver. However, their expression patterns were varied depending on the tissue and mouse strain. Taken together, $T.$ $gondii$-susceptible C57BL/6 mice expressed higher levels of these 5 genes than did $T.$ $gondii$-resistant BALB/c mice, particularly in the spleen and liver. And ALDH1A2 and PLAU expressions were increased acutely, whereas BEX2, CCL3 and EGR2 expressions were increased lately. Thus, these demonstrate that host genetic factors exert a strong impact on the expression of these 5 genes and their expression patterns were varied depending on the gene or tissue.

• Korean journal of applied entomology
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• v.52 no.4
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• pp.437-448
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• 2013

Hemipteran bugs, which were previously considered as secondary pests, have currently become important pests of numerous crops. Among them, Riptortus pedestris (Fabricius) is a major species that occurs in Korea, Japan, China, and South Asian countries. Riptortus pedestris infests leguminous crops like soybean, vetches, and red clover; fruit trees like persimmon and yuju; and grains like barley, foxtail millet, broomcorn, and sorghum. Riptortus pedestris causes the greatest damage to soybean, as it is the most suitable host for the bug. Feeding damage during pod formation significantly reduces the yield of soybean. Currently, 17 insecticides, including diazinon and etofenprox, are registered for the control of hemipteran bugs in Korea, and growers apply insecticides two to three times on a regular basis. Aggregation pheromone traps are widely used as a monitoring tool and partial control measure. The aggregation pheromone of R. pedestris attracts conspecific adults and nymphs and is used for food exploitation rather than sexual attraction. In addition, the pheromone serves as a kairomone for egg parasitoids such as Gryon japonicum (Ashmead) and Ooencyrtus nezarae Ishii. As a new method of pest management, nonviable host eggs were included in the pheromone trap to catch R. pedestris and propagate parasitoids. As a part of cultural practices, resistant soybean varieties with specific color and size of pod and control of flowering time through the alteration of planting date can be used. For the effective management of R. pedestris in the near future, development of cultural practices that can support natural control factors and the use of multiple control tactics are needed.