• Title/Summary/Keyword: Hypervirulent

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Isolation of Hypervirulent Agrobacterium spp from Korea and Application for Transformation of Tobacco (한국산 고감염 Agrobacterium spp의 분리 및 연초의 형질전환에 이용)

  • 양덕춘;정재훈;이정명
    • Korean Journal of Plant Tissue Culture
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    • v.25 no.3
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    • pp.207-217
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    • 1998
  • Total of 78 strains were characterized based on the morphological characteristics of colonies isolated on Schroth, and New & Kerr's media for selection of hypervirulent wild-type Agrobacterium spp from galls, hairy root-like process and soil of Populus, Malus, Salix and Diopyros in Korea. Among them, 48 strains were able to induce tumors in carrot disc. Hypervirulent A. tumefaciens SP101 and SM042 were identified as biotype 1 and biotype 2, respectively, These strains formed fast growing, larger tumors as compared to those induced by other strains. The binary vector pGA643 with kanamycin resistant gene was mobilized from E. coli MC100 into A. tumefaciens strain SM042 isolated from soil, and/or disarmed vector PC2760 using a triparental mating method with E. coli HB101/pRK2013, and transconjugants, A. tumefaciens SM643 and PC643 were obtained in minimal media containing kanamycin and tetracycline. Tobacco tissues were cocultivated with conjugant Agrobacterium and then transferred to selective medium with 2,4-D and kanamycin to induce the transformants. Calli were formed more efficiently in cocultivation with A. tumefaciens SM643 than that with A. tumefaciens PC643. Most of calli transformed with A. tumefaciens PC643 were friable and regenerated into normal plantlets, while the calli transformed with A. tumefaciens SM643 were compact, hard, and mixed with friable calli. The friable calli formed normal shoots, while compact calli did not form shoots but only grew to typical compact tumor calli. When the shoots formed directly from tobacco stems without callus induction after transformation by A. tumefaciens SM643 with wild-type Ti-plasmid, normal transformed plants can be induced without using disarmed Ti-plasmid.

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Clostridium difficile in Children: To Treat or Not to Treat?

  • Shim, Jung Ok
    • Pediatric Gastroenterology, Hepatology & Nutrition
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    • v.17 no.2
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    • pp.80-84
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    • 2014
  • Clostridium difficile infection has been increasing since 2000 in children and in adults. Frequent antibiotics use, comorbidity, and the development of hypervirulent strains have increased the risk of infection. Despite the high carriage rates of C. difficile, infants rarely develop clinical infection. Discontinuing antibiotics and supportive management usually leads to resolution of disease. Antibiotics use should be stratified depending on the patient's age and severity of the disease.

Lower Leg Abscess in Klebsiella pneumoniae Invasive Syndrome Caused by Hypervirulent Klebsiella pneumoniae: A Case Report (고병원 폐렴막대균 침습 증후군에 동반된 하지 농양: 증례 보고)

  • Kim, Dong Seok;Kim, Dae-Yoo
    • Journal of Korean Foot and Ankle Society
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    • v.26 no.2
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    • pp.107-110
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    • 2022
  • Klebsiella pneumoniae is known to cause an invasive syndrome characterized by primary liver abscess associated with metastatic infection. The characteristics of the metastatic infection involving the musculoskeletal system in this invasive syndrome are not well understood. The authors present a case report of a patient who developed abscesses of the lower extremities along with abscesses of multiple organs, such as the liver and eye, caused by K. pneumoniae. The patient was diagnosed early, and the infection was successfully controlled after several surgical treatments.

Isolation and identification of Agrobacterium spp. using carrot disc and transformation of Nicotiana gluca by selected strains (당근 절편을 이용한 Agrobacterium spp. 분리, 동정과 선발균주에 의한 연초의 형질전환)

  • Yang, Deok-Chun;Yang, D.C.;Choi, K.T.
    • Journal of the Korean Society of Tobacco Science
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    • v.13 no.1
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    • pp.43-52
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    • 1991
  • These studies were carred out to obtain the transformant from tobacco cells by Agrobacterium spp. from crown gall and soil at the natural field in Korea, and identified their virulence. Kodo's and Clark's selective media were used for isolation of Agrobacterium spp. In these media, total of 99 strains were characterized based on the morphological characteristics of colonies. Among them 34 strains were able to induce on carrot discs. And hypervirulent strains C23-1 and K29-1 were identified as Agrobacterium tumefaciens biotype 1 and biotype 2, respectively. These strains formed fast growing, larger gall as compared to those induced by other strains on the carrot discs. Transformed tobacco callus was initiated on the phytohormone free MS medium with 250$\mu\textrm{g}$/ml carbenicillin after co-cultivation of tobacco stem explants and Agrobacteria. On the phytohormone free media, shoot was rarely formed from transformed callus. However, these shoot were teratoma shoots which were not grown as normal shoot, and teratoma shoot from transformant by C23-1 was smaller than that of K29-1.

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Transformation of Carrot (Daucus carota) Cells Using Binary Vector System (Binary Vector System을 이용한 당근 (Daucus carota) 세포의 형질전환)

  • 양덕조;이성택
    • KSBB Journal
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    • v.5 no.3
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    • pp.247-253
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    • 1990
  • These studies were carried out to obtain the transformant from carrot cells by using binary vector pGA472 with NPT II gene to confer kanamycin resistance in the plant cells. The binary vector pGA472 was mobilized from E. coli MC1000 into A. tumefaciens strains isolated in the Korea, C23-1. K29-1, and disarmed Ti-plasmid PC2760, and A28l using a tri-parental mating method with E. coli HB101/pRK2013. Transconjugants, C23-1/pGA472, K29-1/pGA472, PC2 760/pGA472 and A28l/pGA472 were obtaind on the minimum AB media containing tetracycline and kanamycin, were comfirmed to hold the Ti-plasmid and pGA472 binary vector on the 0.7% agarose gel. Transformed carrot calli were initiated on the MS media supplemented with l00$\mu\textrm{g}$/ml kanamycin and 250$\mu\textrm{g}$/ml carbenicillin after co-cultivation of carrot explant and transconjugant Agrobacteria. Selected callus was grown vigouousley for subculture on the medium containing 100$\mu\textrm{g}$/ml kanamycin, thus indication that the selected callus was transformed with NPT II gene.

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Protective Efficacy and Immunogenicity of Rv0351/Rv3628 Subunit Vaccine Formulated in Different Adjuvants Against Mycobacterium tuberculosis Infection

  • Kee Woong Kwon;Tae Gun Kang;Ara Lee;Seung Mo Jin;Yong Taik Lim;Sung Jae Shin;Sang-Jun Ha
    • IMMUNE NETWORK
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    • v.23 no.2
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    • pp.16.1-16.19
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    • 2023
  • Bacillus Calmette-Guerin (BCG) vaccine is the only licensed vaccine for tuberculosis (TB) prevention. Previously, our group demonstrated the vaccine potential of Rv0351 and Rv3628 against Mycobacterium tuberculosis (Mtb) infection by directing Th1-biased CD4+ T cells co-expressing IFN-γ, TNF-α, and IL-2 in the lungs. Here, we assessed immunogenicity and vaccine potential of the combined Ags (Rv0351/Rv3628) formulated in different adjuvants as subunit booster in BCG-primed mice against hypervirulent clinical Mtb strain K (Mtb K). Compared to BCG-only or subunit-only vaccine, BCG prime and subunit boost regimen exhibited significantly enhanced Th1 response. Next, we evaluated the immunogenicity to the combined Ags when formulated with four different types of monophosphoryl lipid A (MPL)-based adjuvants: 1) dimethyldioctadecylammonium bromide (DDA), MPL, and trehalose dicorynomycolate (TDM) in liposome form (DMT), 2) MPL and Poly I:C in liposome form (MP), 3) MPL, Poly I:C, and QS21 in liposome form (MPQ), and 4) MPL and Poly I:C in squalene emulsion form (MPS). MPQ and MPS displayed greater adjuvancity in Th1 induction than DMT or MP did. Especially, BCG prime and subunit-MPS boost regimen significantly reduced the bacterial loads and pulmonary inflammation against Mtb K infection when compared to BCG-only vaccine at a chronic stage of TB disease. Collectively, our findings highlighted the importance of adjuvant components and formulation to induce the enhanced protection with an optimal Th1 response.