• Korean Journal of Veterinary Research
• /
• v.25 no.1
• /
• pp.7-17
• /
• 1985

Many investigators have been pursuing various attempts so far to produce hepatitis B surface antigen(HBsAg) vaccines using the techniques such as isolation from plasma of chronic HBsAg carrier, recombinant DNA technique or preparation of synthetic peptides specific for immunogenic determinants. Hepatitis B virus can not grow on any cell lines by the tissue culture technique at the present time. The plasma of chronic HBsAg carrier is expensive and its source is limited. The HBsAg from the recombinant DNA technique gave still very low yield. Another approach, therefore, has been initiated to develop a synthetic hepatitis B virus vaccine. The possible use of several distinct synthetic vaccines in prophylaxis can be facilitated by availability of full synthetic immunogens. Peptides synthesized for potential application as antiviral vaccines have been mostly tested in the form of conjugates with carrier proteins, although the free synthetic peptide can be immunogenic. To understand basic knowledges on the antigenicity and immunogenicity of a synthetic peptide specific for major immunogenic determinant of HBsAg, a nonapeptide, $H_2N^{139}Cys-Thr-Lys-Pro-Thr-Asp-Gly-^{146}Asn-Aba$ COOH, which corresponds to HBsAg amino acid residues 139 to 147, was synthesized by the Merrifield's solid-phase method with a slight modification. The antigenicity and immunogenicity of this specific synthetic peptide were examined comparing with purified plasma-derived natural HBsAg. The results obtained are as follows; 1. The peptide synthesized showed the identical amino acid composition to the theoretical value. The degree of purification and molecular weight were acertained by methods of high performance liquid chromatography and mass spectrometry. 2. Using m-maleimidobenzoyl-N-hydroxysuccinimide ester as a conjugating agent, the synthetic peptide was conjugated to rabbit albumin and ${\gamma}$-globulin, tetanus and diphtheria toxoids, and keyhole limpet hemocyanin. Their conjugation yields were 8.3, 9.5, 15.8, 13.5, and 11.2%, respectively. 3. The natural HBsAg was purified from plasma of chronic HBsAg carrier. By the electron microscopic observation of the purified natural HBsAg preparation, no Dane particles were observed and the preparation showed negative DNA polymerase activity. 4. Antigenicity of the synthetic peptide and the plasma-derived natural HBsAg was determined by competition radioimmunoassay using $^{125}I$-natural HBsAg. Their 50% inhibitions appeared as $90{\mu}g/ml$ and $0.12{\mu}g/ml$ for the synthetic peptide and the natural HBsAg, respectively. This indicates that the former was about 750-fold less antigenic than the latter. 5. Immunogenicity of the synthetic peptide was determined by administering the peptide-carrier conjugates into rabbits with and without Freund's complete adjuvant. Regardless the carrier proteins and adjuvant, positive immune responses to the synthetic peptide were observed. The higher antibody titers, however, were shown in the groups administered with Freund's complete adjuvant. 6. Immunizing dose 50% in mice of the various peptide-carrier conjugates was 5.47, 6.00, 65.16, 31.25 and $13.03{\mu}g/dose$ for rabbit albumin and ${\gamma}$-globulin, tetanus and diphtheria toxoids, and keyhole limpet hemocyanin, respectively, while the natural HBsAg showed $0.65{\mu}g/dose$. 7. It was postulated that homologous proteins prefer to heterologous ones as the carriers.

• Pediatric Infection and Vaccine
• /
• v.19 no.1
• /
• pp.28-36
• /
• 2012

Purpose : This study was conducted to evaluate epidemiological data of the viral pathogens obtained from stool exams and provide information on the regional prevalence of infectious diarrheal disease west in Gyeonggi Province, Korea. Methods : We enrolled a cohort of children <10 years of age admitted for treatment of acute diarrhea at Bucheon St. Mary's Hospital, College of Medicine, The Catholic University of Korea. In total, 310 fecal specimens, documented to be free of common bacterial pathogens, were collected from pediatric patients during a 12-month period from January to December 2009 and were tested for the presence of rotavirus, parechovirus, adenovirus, astrovirus, enterovirus, and norovirus using polymerase chain reaction (PCR) and reverse transcription polymerase chain reaction (RT-PCR) assay. Results : The most common virus was parechovirus (16%), followed by adenovirus (15%), astrovirus (14%), rotavirus (13%), and enterovirus (5%). Interestingly, only one of the specimens was positive for norovirus. Single infection cases were detected in 173 (55.8%) of the 310 children, whereas mixed viral infections were detected in 10 (3.2%) of the same children. Viral gastroenteritis generally showed a double peak of incidence. Parechovirus, rotavirus, and adenovirus shared a similar pattern of peak incidence with overall viruses; however, astrovirus infections occurred more frequently in the spring. Eighty-five percent of the confirmed viral gastroenteritis cases developed in under 24 months. Conclusion : The results support the importance of parechovirus, adenovirus, astrovirus, and enterovirus as causative agents of diarrhea in children, which may be underestimated by current routine diagnostic testing.

• Korean Journal of Poultry Science
• /
• v.40 no.4
• /
• pp.379-388
• /
• 2013

Avian paramyxovirus (APMV) type 4 and 6 were isolated during an avian influenza (AI) surveillance program of wild birds. This study also conducted experimental infection of wild-bird-origin APMV type 4 and 6 in specific pathogen free (SPF) chickens to study pathogenicity and transmission within domestic flocks. In addition, serological prevalence data of APMV type 4 and 6 in domestic fowls was conducted with chicken sera collected from 2007 to 2009 in order to understand infection status. The results of the animal experiment showed that APMV type 4 and 6 had the ability to infect chickens with sero-conversion and to transmit the virus from infected birds to contacted birds, but showed low pathogenicity. Serological tests revealed that APMV type 4 was widespread in the poultry industry, especially in layer flocks, but the positive rate for APMV type 6 was very low. This study concluded that wild bird-origin APMV type 4 and 6 could infect the chickens by inter-species transmission and the seroprevalence of APMV type 4 was quite high in Korean poultry. However, since almost all the chicken flocks had a high level of antibody titer against APMV type 1, there was possibility of cross reaction between APMV type 1 and 4, which made the interpretations more complicated. In order to understand infection status in the natural environment, additional study is necessary regarding the seroprevalence of APMV type 4 and 6 in the wild bird population.

• Korean Journal of Veterinary Research
• /
• v.26 no.1
• /
• pp.87-92
• /
• 1986

The present surveys were conducted in attempts to investigate the health situation of horses in Korea through mass-screening the samples serologically, bacteriologically and clinically. A total of 575 horses were sampled randomly, comprising 126 from the Korean Horse Affairs Association, 288 from the Korean Equestrian Federation and 161 from the Jeju ponies. Each of the samples taken was tested for diagnoses of 18 horse diseases including African horse sickness. Summarised below are the results obtained from this surveys. 1. From results of the serological survey it is evident that Korea is currently free from African horse sickness, dourine, glanders, vesicular stomatits, equine piroplasmosis, equine viral arteritis, Venezuelan encephalomyelitis and contagious equine metritis. Constant vigilence with strengthened quarantine measures is thus vital for maintaining freedom of any those diseases in Korea. 2. No clinical case was observed with any of signs or symptoms of infectious lymphangitis, anthrax and infestations with ringworm, mange or scab. However, continuous follow-up is required for establishing the evidence of no occurrence of the diseases in Korea. 3. One case of seropositive to equine infectious anemia may fully justify systematic and regular testings for the whole population of horse in Korea. 4. It is manifested that equine rhinopneumonitis, Japanese encephalitis and Getah virus infection are well established in Korea, together with the presence of equine infectious abortion(Salmonella abortus equi). This strongly entails preventive precautions before entry into Korea for the horses participating in the 1986 Asian Games and the 1988 Seoul Olympics.

• Journal of Plant Biotechnology
• /
• v.1 no.1
• /
• pp.1-7
• /
• 1999

Large-scale cultures of plant cell, tissue, and organ have been achieved by using BTBB. When different sized BTBBs (5 L, 20 L, 100 L, 300 L, and 500 L) were tested for the culture of yew cells (Taxus cuspidata Sieb. et Zucc.), cell growth increment reached to 94.5% in SCV after 24 days of culture with 30% of inoculation cell density. However, there were some variations in the production of taxol and its derivatives among the BTBBs of different size. Approximate 4 ㎎/l of taxol and 84 ㎎/l of total taxanes were obtained by using a 500L BTBB after 6 weeks of culture. With a 20L BTBB, about 20,000 cuttings of virus-free potatoes (cv. Dejima) could be obtained by inoculating 128 explants and maintaining 8 weeks under 16 hr light illumination. The frequency of ex vitro rooting of the cuttings revealed as more than 99% under 30% shade. By incorporating two-stage culture process consisting of multiple bulblet formation in solid medium and bulblet development in liquid medium, mass propagation of lily through bioreactor seemed to be possible. In the case of 'Marcopolo', the growth of mini-bulblets in BTBB was nearly 10 folds faster than that of the solid medium. Time course study revealed that maximum MAR yield of ginseng (Panax ginseng C. A. Meyer) in a 5 L and 20 L BTBB after 8 weeks of culture was 500 g and 2.2 ㎏, respectively. By cutting the MAR once and/or twice during the culture, the yield of root biomass could be increased more than 50% in fresh weight at the time of harvest. With initial inoculum of 500 g of sliced MAR in a 500 L BTBB, 74.8 ㎏ of adventitious root mass was obtained after 8 weeks of culture. The average content of total ginseng saponin obtained from small-scale and/or pilotscale BTBBs was approximately 1% per gram dry weight. Based on our results, we suggest that large-scale cultures of plant cell, tissue, and organ using BTBB system should be quite a feasible approach when compared with conventional method of tissue culture.

• Journal of Plant Biotechnology
• /
• v.35 no.1
• /
• pp.75-80
• /
• 2008

In vitro culture of shoot tip of garlic (Allium sativium L. cv. Seosan) was carried out to find medium condition of the induction of multiple shoots and bulbing for muliproduction of virus-free seed bulbs. For this work, tank culture was introduced. In shoot tip culture on MS solid medium the induction of multiple shoots and bulbing were better by adding 3% sucrose than 8%. Supplementation with 2mg/L 2ip and 0.2 mg/L IAA in this medium was effective. Three point three shoots including 2.7 bulbs were formed from a shoot tip after cultivation for 30 days on this medium. Bulbing of garlic in liquid culture with plastic water tank of 20L supplied air at the side of the lower part was better by adding 3% sucrose than 8% by subculture for 45 days with shoots obtained from shoot tip culture for 30 days on soid MS medium. Shoot growth was vigorous at 3% sucrose however bulb growth was more effective on the medium of 8% sucrose. Because of the effectiveness on solid medium added 3% sucrose, 2 mg/L 2ip and 0.2 mg/L IAA for initial production of multi-shoot in stem tip culture and the effectiveness in liquid culture with water tank for growth of bulbs, the method of two-step culture could be introduced for the multiple production of seed bulb of high quality. It was more desirable by supply of 0.2 mg/L BA and 0.02 mg/L NAA at tank culture time. But growth of the bulbs became poor by increasing concentration of NAA of the medium.

• Horticultural Science & Technology
• /
• v.31 no.2
• /
• pp.165-172
• /
• 2013

This study was conducted to investigate the effect of bulblet size on growth and bulb enlargement of Lilium Oriental hybrids, such as 'Sorbonne', 'Siberia', and 'Casa Blanca', grown in areas of high altitude (780 m), in 2009. The bulblets were oriented from tissue culture and planted to produce virus-free bulblets. All the three cultivars showed high vitality, with more than 93% producing shoots, even from small bulblets with a bulb circumference (BC) of less than 6 cm. Bulblets with BC 9-10 cm showed an increased height and number of leaves rapidly to induce the phase conversation from vegetative growth to reproductive growth. The bulblets of BC 9-10 cm in 'Sorbonne', 'Siberia', and 'Casa Blanca' had 2.0, 2.9, and 2.8 flower bud sets per plant, respectively. However, the flowers from those bulblets were not adequate as standard bulbs to produce cut-flowers for the domestic market. The larger bulblets showed more prosperous characteristics in growth and development of Lilium Oriental hybrids. Small bulblets had a high occurrence of viruses and leaf blight symptoms during cultivation, indicating the aggravated disease symptoms in the previously infected bulbs. 'Sorbonne' cultivars showed a high rate of enlargement of bulbs, and small bulblets under BC 6 cm produced more than 23% of the standard bulbs of BC 14-16 cm, which could produce cut-flowers for export. However, 'Casa Blanca' bulblets with BC 6-9 cm produced low bulbs of BC 14-16 cm at 21% level. 'Casa Blanca' cultivars had more bulb roots, longer root lengths, and higher weights than 'Sorbonne' and 'Siberia' cultivars. 'Casa Blanca' cultivars with BC over 9-10 cm grew rapidly and produced a high quantity of bulbs. In these results, 'Sorbonne' bulblets of BC 9-10, 'Siberia' bulblets of BC 10-12 cm, and 'Casa Blanca' bulblets of BC 10-12 cm produced 89%, 86%, and 93% of the standard bulbs of BC 14-16 cm, respectively. It is recommended that bulblets larger than the above sizes be used to produce cut-flowers for the export market. Experiment results suggest that production of bulbs larger than BC 18 cm requires bulblets that are larger than BC 12-14 cm of the three cultivars for the highest quality cut-flowers.

• Korean Journal of Veterinary Research
• /
• v.47 no.2
• /
• pp.175-185
• /
• 2007

This study was carried out to investigate the pathogenesis and pathogenicity of the porcine circovirus type 2 (PCV2) Korean isolate from weaned pigs. Twenty four weaned pigs, PCV2, porcine reproductive and respiratory syndrome virus (PRRSV) and porcine parvovirus (PPV) antibodies free, were allocated to 4 groups (n = 6). Six pigs were inoculated intranasally with PCV2 alone, 6 with PCV2 and PRRSV, 6 with the combined PCV2/PRRSV/PPV inoculum, and 6 were remained as a uninoculated negative control. Pigs were killed 3 and 6 weeks after inoculation and tissue samples examined for gross and microscopic lesions and for the presence of PCV2 antigens and nucleic acids. Experimentally inoculated pigs were evaluated for 3 considerations: 1. development of postweaning multisystemic wasting syndrome (PMWS), 2. distribution of viral antigens by immunohistochemistry and polymerase chain reaction (PCR), and 3. cytokine mRNA levels in lymph nodes. Pigs inoculated with PCV2/PRRSV/PPV showed typical clinical signs, gross findings, and histopathologic characteristics of PMWS. In the PCV2/PRRSV/PPV inoculated group, the PCV2 antigen was widely distributed in various parenchymal organs such as brain, spinal cord, tonsil, lymph nodes, lung, heart, liver, kidney, spleen, and peyer's patch. Lymph node mRNA expression of IL-$1{\alpha}$, IL-2R and IL-8 was determined by real-time PCR. The pigs of PCV2/PRRSV and PCV2/PRRSV/PPV inoculation group, the mRNA expression was characterized by a decrease of IL-$1{\alpha}$, IL-2R and IL-8. The decrease of cytokine mRNA represent the state of T cell immuno-suppression in pig, and nicely support the evidence for the impairment of immune system in pigs with PMWS. In conclusion, PCV2 infection and some additional infectious causes such as PRRSV and/or PPV are warranted for the presence of PMWS in weaned pigs in Korea.

• Journal of Sericultural and Entomological Science
• /
• v.44 no.2
• /
• pp.69-73
• /
• 2002

For the practical use of nuecin protein, we tried to overexpress nuecin using Bm5 insect cell and Bombyx mori. We inserted nuecin cDNA into pBm10po1-Xa vector derived from B. mori nuclear polyhedrosis virus (BmNPV), and expressed in Bm5 cells and B. mori respectively. SDS-PAGE and Northern blot analysis showed an expressed of the protein when baculovirus expression vector system (BEVS) was used. The amount of intracellular protein is abundant, but the amount of extracellular protein is poor. The results suggest that the biologically active nuecin protein produced by using BEVS is poor because incresed level of misfolded nuecin by the strong promoter, polyhedrin and p 10 of BEVS, decrease the level of free chaperons and foldases by binding with them.

• Journal of Life Science
• /
• v.26 no.2
• /
• pp.265-274
• /
• 2016

Toxin-antitoxin (TA) systems are ubiquitous genetic modules that are evolutionally conserved in bacteria and archaea. TA systems composed of an intracellular toxin and its antidote (antitoxin) are currently classified into five types. Commonly, activation of toxins under stress conditions inhibits diverse cellular processes and consequently induces cell death or reversible growth inhibition. These effects of toxins play various physiological roles in such as regulation of gene expression, growth control (stress response), programmed cell arrest, persister cells, programmed cell death, phage protection, stabilization of mobile genetic elements or postsegregational killing of plasmid-free cells. Accordingly, bacterial TA systems are commonly considered as stress-responsive genetic modules. However, molecule screening for activation of toxin in TA system is available as development of antimicrobial agents. In addition, cytotoxic effect induced by toxin is used as effective cloning method with antitoxic effect of antitoxin; consequently cells containing cloning vector inserted a target gene can survive and false-positive transformants are removed. Also, TA system is applicable to efficient single protein production in biotechnology industry because toxins that are site-specific ribonuclease inhibit protein synthesis except for target protein. Furthermore, some TA systems that induce apoptosis in eukaryotic cells such as cancer cells or virus-infected cells would have a wide range of applications in eukaryotes, and it will lead to new ways of treating human disease. In this review, we summarize the current knowledge on bacterial TA systems and their applications.