• Korean Journal of Poultry Science
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• v.26 no.2
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• pp.119-129
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• 1999

In recent years, numerous researches have been carried out in author's laboratory to develop several kinds of methods for producing transgened chicken, leaving a lot of new findings. Some of them are very useful to search for new approaches necessary to improve the efficiency of hatchability and the survival rate of developing trasgened embryos. The results obtained hitherto might be summarized as follows: (1) foreign gene(Lac Z/ Miw Z) introduced into blastodermal cells of developing embryos was successfully transferred to embryos, leading to the production of primordial germ cells(PGCs) carrying foreign DNA. However, hatched hickens failed to show the incorporation of introduced gene into the gonads. (2) When foreign gene was introduced into germinal crescent region (GCR), the gene was also efficiently incorporated into germ cells, resulting in the production of transgened chickens(offspring) which produced fruther offspring having foreign gene in the gonads. In this case, 2nd and 3rd generations of chickens were obtained through the reproduction of transgened birds. (3) In another way, the gene was injected into blood vessels of developing embryos at stage 13∼15, creating PGCs having foreign gene, and produced some transgened chickens. In this work, the PGCs were transfered between embryos, resulting in the production of transgenic chickens. (4) in these experiments, PGCs were effectively employed for producing transgenic birds, developing some kinds of chimeric chickens from homo- or hetero-sexual transfer of the PGCs from embryos. This means that the gonads from donor PGCs developed in some degree to the stage of hatching. However, these gonads showed slightly abnormal tissues similar to ovotestis like organs through histological examination. (5) Avian Leukosis Virus(ALV) induced B cell line(DT40) successfully carried foreign genes into chicken embryos, suggesting the possibility of the cells as a vector in this field of study in the future. (6) Inter-embryonic transfer of the PGCs also gave us some.

• Journal of Microbiology and Biotechnology
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• v.23 no.5
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• pp.630-636
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• 2013

Recently, there has been a growing body of evidence showing that cellular microRNAs (miRNAs) are involved in virus-host interactions. Numerous studies have focused on analyses of the expression profiles of cellular miRNAs, but the expression patterns of Dicer, which is responsible for the generation of miRNAs, have only rarely been explored in Gallus gallus. We developed a duplex real-time reverse transcriptase polymerase chain reaction (RT-PCR) assay for the relative quantification of the mRNAs of Dicer and ${\beta}$-actin in G. gallus. To apply this method, the expression of Dicer in avian cells after infection with avian leukosis virus subgroup J (ALV-J) was detected using our established duplex real-time RT-PCR. The duplex real-time RT-PCR assay is sufficiently sensitive, specific, accurate, reproducible, and cost-effective for the detection of Dicer in G. gallus. Furthermore, this study, for the first time, demonstrated that ALV-J can induce differential expression of Dicer mRNA in the ALV-J-infected cells.

• Proceedings of the Korean Society of Veterinary Pathology Conference
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• 2002.11a
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• pp.150-150
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• 2002

40두 규모의 농장에서 사육된 홀스타인 종, 4개월령의 수컷 송아지에서 거세 후 고열, 식욕부진, 기침 등의 증상과 함께 전신 체표 림프절의 종대가 관찰되어 백혈병으로 잠정진단 하고 도태를 권유하였으나 축주가 치료를 원해 항생제와 해열제 및 기타 대증요법을 실시한 후 치료반응이 없어 폐사하여 부검을 실시하였다. 혈액 검사상 이상핵과 다형핵을 가진 다수의 림프구 및 백혈구, 호중구, 림프구 및 단핵구의 증가가 관찰되었다. 또한 백혈병 바이러스에 대한 분리 및 PCR 검사는 음성이었다. 부검 소견으로 체표 림프절, 슬관절 부위 및 비장과 간의 종대가 관찰되었으며 비장 중심에 12x11 cm의 종괴와 폐의 전엽부 유착 및 폐문, 종격동 림프절의 심한 종대가 관찰되었다. 견갑전 림프절을 비롯하여 대퇴골 전, 서혜, 폐문, 이하림프절 등 전신 림프절의 종대 및 소성의 연한 황색의 매끄러운 절단면을 보였다. 전지 관절의 종대와 관절강 내부는 증가된 농성 활액을 보였으며 고관절 강 내에 농성 활액의 증가와 공기 노출 후 젤리양 응고를 보였다. 심장은 장액성 위축과 함께 섬외막성 점상출혈이 나타났다. 병리조직학적 소견으로 비장은 지주 주변에 미성숙형의 세포들의 침윤이 보이며 유사분열상이 다수 관찰되었고 백색 수질에도 유사분열상의 증가와 함께 림프아구성 세포들이 다수 나타났다. 이들 주요한 비정상 세포들은 다형성의 큰 핵을 가진 다양한 림프아구의 형태를 지녔으며 핵내 공포가 인정되었다. 비장의 종괴 주변에는 증식된 섬유조직으로 둘러싸여 있었으며 미세농양 형성되어 있고, 일부 석회화가 진행된 부위도 있었다. 간소엽성 중심성 울혈과 가벼운 간세포내 지방침윤, 혈관 내 림프아구 형태의 세포와 소수의 호중구가 관찰되었다. 간삼조 주변에는 가볍거나 중등도의 단핵세포의 침윤이 미만성으로 관찰되었다. 폐에서는 중등도의 기관지 폐렴과 함께 일부는 무기폐가 관찰되었으며 폐포강과 세기관지내에는 염증성 삼출물이 다량 들어 있었다. 다병소성 미세농양과 함께 괴사가 있었고 실질의 섬유화가 진행되어 있었다. 또한 중등도의 간질성 신장염과 림프절은 지주 주변에 간극 내 비정상 림프구 세포의 형태는 비장의 그것과 유사하였으며 적수와 백수의 구이 힘들며 림프소절이 증가되어 있었다. 한 시야에서 유사분열상이 6-8 개로 그 지수가 매우 높으며 이와 더불어 큰 림프구가 전반에 걸쳐 침윤되어 있었다. 주변부 동(sinus)에는 많은 물질들이 침윤되어 있으며 렴프소절내 미만성의 성상현상이 관찰되었다. 회장은 파이어판내 심한 림프구 소실이 나타났다. 이상의 소견을 바탕으로 본 증례는 산재성 송아지 백혈병으로 진단되었다

• Journal of Animal Science and Technology
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• v.63 no.4
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• pp.751-758
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• 2021

The recessive white (locus c) phenotype observed in chickens is associated with three alleles (recessive white c, albino c^a, and red-eyed white c^re) and causative mutations in the tyrosinase (TYR) gene. The recessive white mutation (c) inhibits the transcription of TYR exon 5 due to a retroviral sequence insertion in intron 4. In this study, we genotyped and sequenced the insertion in TYR intron 4 to identify the mutation causing the unusual white plumage of Yeonsan Ogye chickens, which normally have black plumage. The white chickens had a homozygous recessive white genotype that matched the sequence of the recessive white type, and the inserted sequence exhibited 98% identity with the avian leukosis virus ev-1 sequence. In comparison, brindle and normal chickens had the homozygous color genotype, and their sequences were the same as the wild-type sequence, indicating that this phenotype is derived from other mutation(s). In conclusion, white chickens have a recessive white mutation allele. Since the size of the sample used in this study was limited, further research through securing additional samples to perform validation studies is necessary. Therefore, after validation studies, a selection system for conserving the phenotypic characteristics and genetic diversity of the population could be established if additional studies to elucidate specific phenotype-related genes in Yeonsan Ogye are performed.

• Korean Journal of Poultry Science
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• v.16 no.3
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• pp.175-192
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• 1989

A total of 9, 012 cases was submitted for diagnosis of chicken diseases to Veterinary Research Institute, Rural Development Administration from domestic chicken farms during 18 years from 1971 to 1988. Of them, 6, 181 cases diagnosed as the infectious disease were investigated for the detection rate of infections on basis of you, season , and chicken age. The results obtained were summarized as followings：1. Detection rate or the infections was lowest as 49.3% in the year 1973, and highest as 78.6% in 1985 (average 68.6%). 2. Of infections detected, bacterial diseases were most frequent (32.6%), and followed in order by viral (26.3%), parasitic (7.7%), and fungal diseases (2.1%) in geneal. 3. The most frequently detected bacterial diseases in order of prevalence were mycoplasmosis (8.8%), colibacillosis (8.5%), and staphylococcosis (5.8%), and followed by salmonellosis pullorum disease , yolk sac disease, and salpingitis (0.8-1.5%). 4. In viral diseases, 7.5% of infections detected was lymphoid leukosis and 7.2%-Marek's disease, 4.4%-Newcastle disease, 2.0%-infectious laryngotracheitis, 1.7%-infectious bursal disease, and 1.0%-avian encephalomyelitis, while detection rate of infectious bronchitis, egg drop syndrome '76, and inclusion body hepatitis was less than 1.0%, respectively. 5. The most prevalent parasitic disease was coccidiosis (4.5%), followed by ascariasis (1.4%). The detection rate of other parasitic diseases including leucocytozoonosis, black head , heterakiasis, and ectoparasitosis was very as 0.2-0.7%, respectively： In fungal diseases, 2.0% of infections was detected as aspergillosis, and followed by candidiasis (0.1%). 6. Detection rate of the infections on basis of season was somewhat higher in summer. (27.7%), and autumn (27.7%) than in winter (23.5%), and spring (21.5%) in general. In bacterial, viral, and fungal diseases, there were the similar tendencies of detection rate as in infections, while parasitic diseases were much highly detected in summer (34.3%), and autumn (39.5%) than in any other season. 7. Among bacterial diseases colibacillosis was most frequently detected in summer, and staphylococcosis in autumn. In detection rate of viral diseases, Marek's disease, infectious laryngotracheitis, and infectious bursal disease was highest in summer, lymphold leukosis, fowl pox and egg drop syndrome '76 in autumn, and infectious trachitis in winter, repectively. The majority of important parasitic diseases including coccidiosis were highly detected in summer and autumn. 8. On basis of chicken age, detection rate of infections were highest in chicken of growing period between 30 and 150 days of age (41.4%), and followed by 35.3% in laying chicken over 150 days of age, and 17.3% in chicken of brooding age under 30 days of age. Bacterial, and parasitic diseases were most frequently detected in chicken of growing period, viral diseases in chicken of growing, and laying period as nearly equal rate of detection, and fungal diseases in chicken of brooding age.

• Korean Journal of Veterinary Service
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• v.43 no.3
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• pp.139-145
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• 2020

This study was carried out to identify the occurrence of transovarian transmitted diseases and antibody positive rates among Korean native breeder chickens. The infection rates with Salmonella pullorum and Salmonella gallinarum among 16-week-old, 36-week-old, and 56-week-old breeder chickens and the antibody positive rates to Egg Drop Syndrome '76, Mycoplasma gallisepticum and Mycoplasma synoviae among 16-week-old, 18-week-old, and 56-week-old breeder chickens were identified, and the antibody positive rates to seven major transovarian transmitted diseases among 1-day-old chicks were investigated. As a result, no infection with Salmonella pullorum and Salmonella gallinarum was found among the investigated subjects of all ages. Vaccinated breeder chickens showed the 100% antibody positive rate to Egg Drop Syndrome '76, and unvaccinated breeder chickens showed the 100% antibody negative rate to Mycoplasma gallisepticum and Mycoplasma synoviae, confirming that there was no infection with Mycoplasma gallisepticum and Mycoplasma synoviae. As a result of the antibody tests of the 1-day-old chicks for transovarian transmitted diseases, it was found that vaccinated chicks showed good antibody positive rates to avian encephalomyelitis, chicken infectious anemia, and avian reovirus, confirming that they had power of defense against the relevant infectious diseases, and that unvaccinated chicks showed the 100% antibody negative rates to avian leukosis, chicken reticuloendotheliosis, and Mycoplasma synoviae, confirming that there was no infection with the relevant diseases. Given that the results of this study showed that among the transovarian transmitted diseases of chickens, there was no history of infection with diseases against which vaccination was not administered and high antibody positive rates were found with diseases against which vaccination was administered, it is judged that chickens with good power of defense against diseases were bred, and it is deemed that constant monitoring and vaccination against transovarian transmitted diseases will be necessary for the control and prevention of the diseases.

• Applied Microscopy
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• v.35 no.1
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• pp.23-30
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• 2005

Many studies have been performed on the bovine leukemia virus (BLV) since bovine leukosis had been reported in 1968 in Korea. However, there was no report on the ultrastructural examination of BLV. An attempt to detect C-type viral particles in the cultured peripheral blood lymphocytes of Holstein-Friesian dairy cattle, was made to determine whether in vitro viral expression might be used as a reliable method to identify the cow which is likely to transmit BLV. In transmission electron microscopic (TEM) examination, the virus particles were found predominantly outside of the lymphocytes even though a few particles were also observed within the membrane bound cytoplasmic vacuoles. All of them were C-type particles consisting of a central, electron-dense core separated by a clear area from a limiting envelope with a unit membrane structure. Virus particles were easily detected in the lymphocyte which was cultured with medium supplemented with either T-lymphocyte mitogen (conconavalin A) or B-lymphocyte mitogen (lipopolysaccharide). Identical viral particles, although fewer, were also consistently present in the lymphocytes cultured with medium which was containing foetal bovine serum (FBS) only and which was containing neither FBS or mitogen. By contrast, no virus particle was detected in extensive examination of lymphocytes before culture. In conclusion, the BLV cultivation and detection methods established in this study could be used as a tool to identify and eliminate the cattle which can transmit the BLV.

• Korean Journal of Veterinary Service
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• v.18 no.1
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• pp.1-21
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• 1995

To elucidate pathogenesis of bovine leukemia virus(BLV) in Korean native goats, the goats experimentally infected with BLV were studied especially for the aspects of infectivity and hematological changes. The experimental goats were examined for 27 months by agar-gel immunodiffusion(AGID) test and syncytium formation assay. During this period, changes of total leucocyte, absolute Iymphocyte and atypical Iymphocyte were examined, and the distribution of surface immunoglobulin ( sIg ) -bearing cells and rosette forming cell (RFC) in the peripheral Iymphocyte were also investigated. By indirect immunofluorescence (IFA) and complement dependent antibody cytotoxicity (CDAC) assay using monoclonal antibody(Mab) against bovine leukosis tumor-associated anti-gen(BL-TAA), changes of BL-TAA positive Iymphocyte in peripheral blood were measured. The results obtained through the experiment were summarized as follows. 1. Antibody titers were measured by AGID using gP51 and P24 antigens. The animals were serologically converted at 2 months post-inoculation(pi) in gP51 antigen, whereas sero-converted at 4 months pi in P24 antigen. In comparison with antibody titers for gP51, P24 antigen showed lower titers throughout the trial period. 2. The peripheral lymphocytes from all of the infected goats, as co-cultivated with F8l cells manifested syncytial formation at 4 months pi. 3. On counting total leucocyte, Iymphocyte and atypical Iymphocyte, two out of four infected goats showed normal distribution, while No 2 of the remaining two revealed temporal and No 3, Persistant increasing number of the cells. 4. The optimal condition of rosette formation of the peripheral Iymphocyte of normal Korean native goats was shown in the sheep erythrocyte treated with 0.1M AET for 30 nun at $37^{\circ}C$. When the Iymphocytes were treated in nylon wool column, the number of sIg-bear-ing cell were increased in the nylon wool adherent cells, but RFC was increased in the non-adherent cells. Of the infected goats, No 2 and No 3 showed significantly increasing number of sIg-bearing cells at 18 months pi. 5. The Iymphocytes of No 2 and No 3 goats reacted positively in IFA using Mab against BL-TAA at 12 months pi and 18 months pi, respectively. In CDAC test, all of four infected goats revealed positive reaction at 24 months pi. The higher positive rates were observed in No 2 and No 3 as compared with the remainders.

• Korean Journal of Veterinary Research
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• v.4 no.1
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• pp.35-42
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• 1964

1). An nanlysis was made of 3,500 postmortem diagnoses for the three years 1961 through 1963 to determine whether there was any actual incidence of avian visceral lymphomntosis in the field. Chickens autopsied, which showed gross alterations were 7.6 percent or 266 cases. The diminished incidence of the disease in second and third years seemed due to decreased total numbers of chicken flocks year by year for the reason of difficult feed supply. 2). Because chickens autopsied in this study were not clearly known of their breeds and lines, no distinct data on the incidence in various breeds were made. Some exact breeds were in too small numbers to have any statistical significance. Inconceivably, no other types of avian leukosis than visceral lymphomatosis had been observed in any appreciable number in this analysis. 3). Pathologic analysis for affected organs was made grossly and microscopically. In the gross pictures, liver, spleen, kidney, ovary, and in some case, intestine principally showed lesions, but its manifestation was variable in different organs. In such organs, livers were affected more frequently, and spleens followed next. The organs were classified and arranged according to the gross alterations, and among their distribution one-half of livers were in diffuse variety; one-fourths in nodular; about one-sevenths in mixed; and granular variety followed next. In the spleen samples, two-thirds were in diffuse variety; one-fourths in nodular; and follicular only in three cases. Ovaries almost showed follicular lesions, the diffused were less than one-fifths of total specimens. Kidneys were occurred almost in diffuse variety. And intestine showed only nodular tomors. Microscopically, 42 cases of visceral lymphomatosis composed of 24 livers, 10 spleens, 3 kidneys, 3 intestines and 2 ovaries were examined. The tumor cells were lymphoid cells showing various component in size, shape and stainability. Mitotic figures were usually present. The proportion of the component cells were various in all cases and there were variations in the distribution of the tumor cells. The types of distribution were classified according to the standard proposed by Horiuchi as nodular, infiltrative and diffuse proliferation. In cases of visceral lymphomatosis of the livers and the spleens the types of infiltrative, nodular and diffuse proliferation could be classified. In the cases of the kidneys the types of diffuse and nodular proliferation were observed. In the cases of the intestines and the ovaries the types of infiltrative and diffuse proliferation were observed respectively.

• Korean Journal of Veterinary Research
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• v.9 no.1
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• pp.23-62
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• 1969

Throughout the studies the following experimental results were obtained and are summarized: 1. Multiplication of agents in primary cell cultures of both GF classical and CR-64 acute strain of Marek's disease infected chicken kidneys was accompanied by the formation of distinct transformed cell foci. This characteristic nature of cell transformation was passaged regularly by addition of dispersed cell from infected cultures to normal chicken kidney cell cultures, and also transferred was the nature of cell transformation to normal chick-embryo liver and neuroglial cell cultures. No cytopathic changes were noticed in inoculated chick-embryo fibroblast cultures. 2. The same cytopathic effects were noticed in normal kidney cell monolayers after the inoculation of whole blood and huffy coat cells derived from both forms of Marek's disease infected chickens. In these cases, however, the number of transformed cell foci appearing was far less than that of uninoculated monolayers prepared directly from the kidneys of Marek's disease infected chickens. 3. The change in cell culture IS regarded as a specific cell transformation focus induced by an oncogenic virus rather than it plaque in slowly progressing cytopathic effect by non-oncogenic viruses, and it is quite similar to RSV focus in chick-embryo fibroblasts in many respects. 4. The infective agent (cell transformable) were extremely cell-associated and could not be separated in an infective state from cells under the experimental conditions. 5. The focus assay of these agents was valid as shown by the high degree of linear correlation (r=0.97 and 0.99) between the relative infected cell concentration (in inoculum) and the transformed cell foci counted. 6. No differences were observed between the GF classical strain and the CR-64 acute strain of Marek's disease as far as cell culture behavior. 7. Characterization of the isolates by physical and chemical treatments, development of internuclear inclusions in Infected cells, and nucleic acid typing by differential stainings and cytochemical treatments indicated that the natures of these cell transformation agents closely resemble to those described fer the group B herpes viruses. 8. Susceptible chicks inoculated with infected kidney tissue culture cells developed specific lesions of Marek's disease, and in a case of prolonged observation after inoculation (5 weeks) the birds developed clinical symptoms and gross lesions of Marek's disease. Kidney cell cultures prepared from those inoculated birds and sacrificed showed a superior recovery of cell transformation property by formation of distinct foci. 9. Electron microscopic study of infected kidney culture cells (GF agent) by negative staining technique revealed virus particles furnishing the properties of herpes viruses. The particle was measured about $100m{\mu}$ and, so far, no herpes virus envelop has been seen from these preparations. 10. No relationship of both isolates to avian leukosis/sarcoma group viruses and PPLO was observed.