• Asian Pacific Journal of Cancer Prevention
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• 제13권2호
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• pp.599-606
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• 2012

The characterization of the whole genome of human papillomavirus type 16 (HPV16) from cervical cancer specimens with multiple infections in comparison with single infection samples as the oncogenic potential of the virus may differ. Cervical carcinoma specimens positive for HPV16 by PCR and INNO-LiPA were randomly selected for whole genome characterization. Two HPV16 single infection and six HPV16 multiple infection specimens were subjected to whole genome analysis by using conserved primers and subsequent sequencing. All HPV16 whole genomes from single infection samples clustered in the European (E) lineage while all multiple infection specimens belonged to the non-European lineage. The variations in nucleotide sequences in E6, E7, E2, L1 and Long control region (LCR) were evaluated. In the E6 region, amino acid changes at L83V were related to increased cancer progression. An amino acid variation N29S within the E7 oncoprotein significantly associated with severity of lesion was also discovered. In all three domains of the E2 gene non synonymous mutations were found. The L1 region showed various mutations which may be related to conformation changes of viral epitopes. Some transcription factor binding sites in the LCR region correlated to virulence were shown on GRE/1, TEF-1, YY14 and Oct-1. HPV16 European variant prone to single infection may harbor a major variation at L83V which significantly increases the risk for developing cervical carcinoma. HPV16 non-European variants prone to multiple infections may require many polymorphisms to enhance the risk of cervical cancer development.

• Journal of Microbiology and Biotechnology
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• 제28권1호
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• pp.122-135
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• 2018

Listeriolysin O (LLO), one of the most immunogenic proteins of Listeria monocytogenes and its main virulence factor, mediates bacterial escape from the phagosome of the infected cell. Thus, its expression in a nonpathogenic bacterial host may enable effective delivery of heterologous antigens to the host cell cytosol and lead to their processing predominantly through the cytosolic MHC class I presentation pathway. The aim of this project was to characterize the delivery of a model antigen, chicken egg ovalbumin (OVA), to the cytosol of dendritic cells by recombinant Bacillus subtilis vegetative cells expressing LLO. Our work indicated that LLO produced by non-sporulating vegetative bacteria was able to support OVA epitope presentation by MHC I molecules on the surface of antigen presenting cells and consequently influence OVA-specific cytotoxic T cell activation. Additionally, it was proven that the genetic context of the epitope sequence is of great importance, as only the native full-sequence OVA fused to the N-terminal fragment of LLO was sufficient for effective epitope delivery and activation of $CD8^+$ lymphocytes. These results demonstrate the necessity for further verification of the fusion antigen potency of enhancing the MHC I presentation, and they prove that LLO-producing B. subtilis may represent a novel and attractive candidate for a vaccine vector.

• 수산해양교육연구
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• 제27권5호
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• pp.1508-1521
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• 2015

Vibrio harveyi is a pathogenic marine bacterium causing systemic symptoms resulting in mass mortalities in fishes and shrimps in aquaculture. Outer membrane proteins(OMPs) are related to the pathogenicity and thus good targets for diagnosis and vaccination for Gram negative bacteria. Recently vaccination strategies using the OMPs have been suggested to control vibriosis in several fish species. In this study, we have isolated V. harveyi from diseased marine fishes from different regions of Korea and investigated genetic variations of four OMP genes including OmpK, OmpU, OmpV and OmpW. Consequently, OmpK and U genes could be divided into 3 subgroups of type I, II, III and type A, B, C, respectively, without any correlation with geographical regions and species while OmpV and W were highly homologous. OmpW gene of V. harveyi FP4138 was fully sequenced and predicted the deduced amino acid sequence to form ${\beta}-barrel$ with hydrophobic channel. Indeed, the immunogenicity of recombinant OmpW produced in Escherichia coli was assessed by vaccinating flounder. As a result, the high antibody response with antibody titer of $4.2{\pm}0.7$ and protection with relative percent survival of 60% against artificial infection of V. harveyi were demonstrated. This result indicates that OmpW is a virulence related factor and it can be a vaccine candidate to prevent a high mortality caused by V. harveyi infection in olive flounder, Paralichthys olivaceus.

• 생명과학회지
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• 제13권1호
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• pp.67-72
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• 2003

위염, 위궤양 및 위암의 원인 균인 Helicobacter pylori 가균체 표면에 다량 함유하며 주된 생존 인자이며 병원성 인자인 urease를 대장균에서 발현시키고 이 효소에 대한 항체 또는 기질과의 특이 상호 작용을 이용하여 두 단계의 간편한 방법에 의하여 정제하였다. 우선 anti-H. pylori Urease IgG-Sepharose column과 urea-Sepharose column을 각각 제조하고 DEAE-Sepharose 음이온 교환수지를 통하여 1차 정제한 시료를 각각 적용하고 제반 조건에서 용출시켰다. Anti-H. pylori urease IgG-Sepharose column의 경우에는 urease 시료가 너무 강력하게 결합함으로써 극단적인 pH조건에서만 용출이 가능함이 관찰되었으므로, 100 mM 탄산 완충액(pH 10.5)으로 최종 용출하였을 때 비교적 순수한 효소를 얻었으나, 비활성이 다소 감소된 것으로 나타났다. 한편, urea-Sepharose에 적용시킨 시료는 100 mM urea-HEB 완충액(pH 7.5)으로 비교적 용이하게 용출되어 비교적 높은 순도와 비활성의 urease 효소를 얻을 수 있었으나 이 경우에는 urease의 smaller subunit인 UreA peptide band의 강도가 다소 감소한 것이 관찰되었다.

• IMMUNE NETWORK
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• 제13권5호
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• pp.213-217
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• 2013

Enterotoxigenic Bacteroides fragilis (ETBF) is a human gut commensal bacteria that causes inflammatory diarrhea and colitis. ETBF also promotes colorectal tumorigenesis in the Min mouse model. The key virulence factor is a secreted metalloprotease called B. fragilis toxin (BFT). BFT induces E-cadherin cleavage, cell rounding, activation of the ${\beta}$-catenin pathway and secretion of IL-8 in colonic epithelial cells. However, the precise mechanism by which these processes occur and how these processes are interrelated is still unclear. E-cadherin form homophilic interactions which tethers adjacent cells. Loss of E-cadherin results in detachment of adjacent cells. Prior studies have suggested that BFT induces IL-8 expression by inducing E-cadherin cleavage; cells that do not express E-cadherin do not secrete IL-8 in response to BFT. In the current study, we found that HT29/C1cells treated with dilute trypsin solution induced E-cadherin degradation and IL-8 secretion, consistent with the hypothesis that E-cadherin cleavage causes IL-8 secretion. However, physical damage to the cell monolayer did not induce IL-8 secretion. We also show that EDTA-mediated disruption of E-cadherin interactions without E-cadherin degradation was sufficient to induce IL-8 secretion. Finally, we determined that HT29/C1 cells treated with LiCl (${\beta}$-catenin activator) induced IL-8 secretion in a dose-dependent and time-dependent manner. Taken together, our results suggest that BFT induced IL-8 secretion may occur by the following process: E-cadherin cleavage, disruption of cellular interactions, activation of the ${\beta}$-catenin pathway and IL-8 expression. However, we further propose that E-cadherin cleavage per se may not be required for BFT induced IL-8 secretion.

• International Journal of Oral Biology
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• 제35권3호
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• pp.121-128
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• 2010

Porphyromonas gingivalis lipopolysaccharide (Pg LPS) is an important virulence factor in chronic periodontitis. The aim of this study was to compare the expression of inflammatory cytokine genes in Escherichia coli LPS (Ec LPS) and Pg LPS-stimulated mouse macrophage RAW 264.7 cells. Cells were treated with Ec LPS and Pg LPS for 18 hours, and the cytokine gene expression profile was assessed using microarrays and confirmed by real-time PCR. Microarray analysis showed that both types of LPS induced a significant increase in the expression of IL-$17{\beta}$, IL-2, Ccl4, Cxcl2 and $TNF{\alpha}$ compared with the control. However, LT-b was up-regulated by Pg LPS but not by Ec LPS. Real-time PCR analysis of these genes showed similar results for LT-b, Ccl4, Cxcl2, and TNF-$\alpha$ but found that IL-$17{\beta}$ and IL-2 were upregulated by Pg LPS but not by Ec LPS. These data indicate that Pg LPS stimulates the transcription of IL-$17{\beta}$, IL-2, Ccl4, Cxcl2, LT-b, and $TNF{\alpha}$, all of which may be involved in the pathogenesis of chronic periodontitis.

• The Plant Pathology Journal
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• 제33권2호
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• pp.125-132
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• 2017

Tan spot (TS), caused by the fungus Pyrenophora tritici-repentis (Died) Drechs, is an important foliar disease of wheat and has become a threat to world wheat production since the 1970s. In this study a globally diverse pre-1940s collection of 247 wheat genotypes was evaluated against Ptr ToxA, P. tritici-repentis race 1, and stem rust to determine if; (i) acquisition of Ptr ToxA by the P. tritici-repentis from Stagonospora nodorum led to increased pathogen virulence or (ii) incorporation of TS susceptibility during development stem rust resistant cultivars led to an increase in TS epidemics globally. Most genotypes were susceptible to stem rust; however, a range of reactions to TS and Ptr ToxA were observed. Four combinations of diseasetoxin reactions were observed among the genotypes; TS susceptible-Ptr ToxA sensitive, TS susceptible-Ptr ToxA insensitive, TS resistant-Ptr ToxA insensitive, and TS resistant-Ptr ToxA toxin sensitive. A weak correlation (r = 0.14 for bread wheat and -0.082 for durum) was observed between stem rust susceptibility and TS resistance. Even though there were no reported epidemics in the pre-1940s, TS sensitive genotypes were widely grown in that period, suggesting that Ptr ToxA may not be an important factor responsible for enhanced prevalence of TS.

• Clinical and Experimental Pediatrics
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• 제58권1호
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• pp.20-27
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• 2015

Purpose: We investigated the molecular types of uropathogenic Escherichia coli (UPEC) by using conventional phylogrouping, multilocus sequence typing (MLST), and fimH genotyping. Methods: Samples of patients younger than 18 years of age were collected from the Chung-Ang University Hospital over 2 years. Conventional phylogenetic grouping for UPEC strains was performed by polymerase chain reaction (PCR). Bacterial strain sequence types (STs) were classified on the basis of the results of partial sequencing of seven housekeeping genes. In addition, we analyzed nucleotide variations in a 424-base pair fragment of fimH, a major virulence factor in UPEC. Results: Sixty-four UPEC isolates were analyzed in this study. Phylogenetic grouping revealed that group B2 was the most common type (n=54, 84%). We identified 16 distinctive STs using MLST. The most common STs were ST95 (35.9%), ST73 (15.6%), ST131 (12.5%), ST69 (7.8%), and ST14 (6.3%). Fourteen fimH allele types were identified, of which 11 had been previously reported, and the remaining three were identified in this study. f1 (n=28, 45.2%) was found to be the most common allele type, followed by f6 and f9 (n=7, 11.3% each). Comparative analysis of the results from the three different molecular typing techniques revealed that both MLST and fimH typing generated more discriminatory UPEC types than did PCR-based phylogrouping. Conclusion: We characterized UPEC molecular types isolated from Korean children by MLST and fimH genotyping. fimH genotyping might serve as a useful molecular test for large epidemiologic studies of UPEC isolates.

• The Plant Pathology Journal
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• 제24권2호
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• pp.183-190
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• 2008

Plant-cell-wall-degrading enzymes (PCWDEs) of Pectobacterium carotovorum subsp. carotovorum are the key virulence factor in pathogenesis of soft rot disease of vegetables. The production of PCWDEs is controlled in a cell density dependent manner to avoid the premature production of PCWDEs and subsequent activation of plant defense. N-oxoacyl-homoserine lactone (OHL) is essential for quorum sensing in the soft rot pathogen and the expI gene is responsible for OHL production. The ExpI homolog isolated from P. carotovorum subsp. carotovorum SL940 had 94% identity with ExpI of E. carotovora subsp. carotovora scc3193 and 74% identity with Carl of E. carotovora subsp. atroseptica. The transgenic plants that express exp I uner the control of CaMV35S promoter were able to produce diffusible OHL. Transgenic plants producing OHL were very resistant to the infection of P. carotovorum subsp. carotovorum. Since the PR1 gene was strongly induced and NPR1 and NPR4 were induced weakly in transgenic plants compared to the wild type, salicylic acid-dependent pathways is likely involved in the resistance to the soft rot pathogen P. carotovorum subsp. carotovorum in ExpI transgenic plants.

• Journal of Microbiology and Biotechnology
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• 제24권2호
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• pp.160-167
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• 2014

Oligopeptidase B (OpdB) is a serine peptidase widespread among bacteria and protozoa that has emerged as a virulence factor despite its function has not yet been precisely established. By using an OpdB-overexpressing Escherichia coli strain, we found that the overexpressed peptidase makes the bacterial cells specifically less susceptible to several proline-rich antimicrobial peptides known to penetrate into the bacterial cytosol, and that its level of activity directly correlates with the degree of resistance. We established that E. coli OpdB can efficiently hydrolyze in vitro cationic antimicrobial peptides up to 30 residues in length, even though they contained several prolines, shortening them to inactive fragments. Two consecutive basic residues are a preferred cleavage site for the peptidase. In the case of a single basic residue, there is no cleavage if proline residues are present in the $P_1$ and $P_2$ positions. These results also indicate that cytosolic peptidases may cause resistance to antimicrobial peptides that have an intracellular mechanism of action, such as the proline-rich peptides, and may contribute to define the substrate specificity of the E. coli OpdB.