• 미생물학회지
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• 제53권4호
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• pp.340-341
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• 2017

Acidovorax citrulli 병원세균은 수박에 과실썩음병을 일으킨다. 이 논문에서는 A. citrulli strain KACC17005 균주의 완전한 게놈 서열을 분석하여 보고한다. 게놈은 총 5,349,924 bp로 구성되어 있으며 G + C 함량이 68.54%이다. 단백질을 coding하는 유전자가 총 4,520개이고, 이들 중 적어도 15개의 유전자들은 감수성 식물에서 병원성을 증가시키거나 저항성 식물에서 면역반응을 유도하는데 중요한 제3형 effector 단백질을 코딩하고 있다.

• Journal of Microbiology and Biotechnology
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• 제18권1호
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• pp.171-175
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• 2008

Here, we report that Vibrio parahaemolyticus induces a rapid remodeling of macrophage actin and activates RhoB GTPase. Mutational analysis revealed that the effects depend on type III secretion system 1 regulated translocation of a V. parahaemolyticus effector protein, VP1686, into the macrophages. Remodeling of actin is shown to be necessary for increased bacterial uptake followed by initiation of apoptosis in macrophages. This provides evidence for functional association of the VP1686 in triggering an eat me-and-die signal to the host.

• The Plant Pathology Journal
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• 제17권2호
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• pp.77-82
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• 2001

Erwinia amylovora causes a devastating disease called fire blight in rosaceous trees and shrubs such as apple, pear, and raspberry. To successfully infect its hosts, the pathogen requires a set of clustered genes termed hrp. Studies on the hrp system of E. amylovora indicated that it consists of three functional classes of genes. Regulation genes including hrpS, hrpS, hrpXY, and hrpL produce proteins that control the expression of other genes in the cluster. Secretion genes, many of which named hrc, encode proteins that may form a transmembrane complex, which is devoted to type III protein secretion. Finally, several genes encode the proteins that are delivered by the protein secretion apparatus. They include harpins, DspE, and other potential effector proteins that may contribute to proliferation of E. amylovora inside the hosts. Harpins are glycine-rich heat-stable elicitors of the hypersensitive response, and induce systemic acquired resistance. The pathogenicity protein DseE is homologous and functionally similar to an avirulence protein of Pseudomonas syringae. The region encompassing the hrpldsp gene cluster of E. amylovora shows features characteristic of a genomic island : a cryptic recombinase/integrase gene and a tRNA gene are present at one end and genes corresponding to those of the Escherichia coli K-12 chromosome are found beyond the region. This island, designated the Hrp pathogenicity island, is more than 60 kilobases in size and carries as many as 60 genes.

• Journal of Microbiology and Biotechnology
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• 제21권7호
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• pp.679-685
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• 2011

Xanthomonas oryzae pv. oryzae (Xoo) produces a putative effector, XoAvrBs2. We expressed XoAvrBs2 homologously in Xoo with a TAP-tag at the C-terminus to enable quantitative analysis of protein expression and secretion. Addition of rice leaf extracts from both Xoo-sensitive and Xoo-resistant rice cultivars to the Xoo cells induced expression of the XoAvrBs2 gene at the transcriptional and translational levels, and also stimulated a remarkable amount of XoAvrBs2 secretion into the medium. In a T3SS-defective Xoo mutant strain, secretion of the TAPtagged XoAvrBs2 was blocked. Thus, we elucidated the transcriptional and translational expressions of the XoAvrBs2 gene in Xoo was induced in vitro by the interaction with rice and the induced secretion of XoAvrBs2 was T3SSdependent. It is the first report to measure the homologous expression and secretion of XoAvrBs2 in vitro by rice leaf extract. Our system for the quantitative analysis of effector protein expression and secretion could be generally used for the study of host-pathogen interactions.

• Journal of Microbiology and Biotechnology
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• 제23권1호
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• pp.118-124
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• 2013

Vibrio parahaemolyticus in uncooked seafood causes acute gastroenteritis. The microorganism has two sets of type III secretion systems and two hemolysins. When it injects its effector proteins into a host cell via type III secretion system 1, one of the type III secretion systems induces secretion of interleukin (IL)-8, a proinflammatory chemokine, through the phosphorylation of ERK 1/2 and p38 MAPK. Although probiotics have beneficial effects on hosts and can help control some infectious diseases, there is little research on the efficacy of probiotics in V. parahaemolyticus infection. Here we pretreated V. parahaemolyticus-infected human intestinal epithelial cells with heat-killed Lactobacillus brevis KB290, a probiotic isolated from fermented vegetables (traditional Japanese pickles) and utilized as an ingredient of beverages and supplementary foods, and demonstrated its efficacy in enhancing IL-8 secretion from V. parahaemolyticus-infected cells. Among the three heat-killed lactic acid bacterial strains we tested, L. brevis KB290 induced the highest level of IL-8 secretions in the infected cells. Relative to control cells (Caco-2 cells pretreated with PBS), V. parahaemolyticus-infected Caco-2 cells pretreated with heat-killed L. brevis KB290 secreted IL-8 earlier, although concentrations were similar 450min after infection. Heat-killed L. brevis KB290 pretreatment also induced earlier ERK 1/2 phosphorylation, greater p38 MAPK phosphorylation, and enhanced IL-8 mRNA expression. Heat-killed L. brevis KB290 accelerated IL-8 secretion, a host cell immune response, in V. parahaemolyticus-infected cells. We consider this to be beneficial because IL-8 plays an important defensive role against infection, and would contribute to the repair of injured epithelial cells.

• 한국식물병리학회:학술대회논문집
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• 한국식물병리학회 2004년도 The 2004 KSPP Annual Meeting & International Symposium
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• pp.65-67
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• 2004

During initial interactions of bacteria with their host plants, most plants recognize the bacterial infections and repel the pathogen by plant defense mechanism. The most active plant defense mechanism is the hypersensitive response (HR) which is the localized induced cell death in the plant at the site of infection by a pathogen. A primary locus induced in gram-negative phytopathogenic bacteria during this initial interaction is the Hrp locus. The Hrp locus is composed of a cluster of genes that encodes the bacteral Type 111 machinery that is involved in the secretion and translocation of effector proteins to the plant cell. DNA sequence analysis of hrp gene in phytopathogenic bacteria has revealed a Hrp pathogenicity is]and (PAI) with a tripartite mosaic structure. For many gram-negative pathogenic bacteria, colonization of the host's tissue depends on the type III protein secretion system (TTSS) which secrets and translocates effector proteins into the host cell. Effectors can be divided into several groups including broad host range effectors, host specific effectors, disease specific effectors, and effectors inhibit host defenses. The role of effectors carrying LRR domain in plant resistance is very elusive since most known plant resistance gene carry LRR domain. Host specific effectors such as several avr gene products are involved in the determination of the host specificity. Almost all the phytopathogenic Xanthomonas spp. carry avrBs1, avrBs2, and avrBs3 homologs. Some strains of X. oryzae pv. oryzae carry more than 10 copies of avrBs3 homologs. However, the functions of all those avr genes in host specificity are not characterized well.;

• 미생물학회지
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• 제50권4호
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• pp.281-284
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• 2014

병원성 균주인 녹농균(Pseudomonas aeruginosa) 감염에 대응하여 나타나는 면역반응은 인체의 항상성 유지에 중요하다. 선행 연구에서 녹농균의 감염에 대응하여 bradykinin receptor (BR)의 발현이 증가됨을 보고하였지만, 발현유도에 관여하는 녹농균 유래인자에 대해서는 보고한 바가 없었다. 이번 연구에서는 녹농균에 의한 BR의 발현은 Type III secretion system (T3SS)이 관여하지만, 기존에 알려진 T3SS인자가 아닌 nucleoside diphosphate kinase (Ndk)에 의한 것으로 조사되었다. 하지만 pDNNDK를 이용한 transfection 실험 결과, Ndk 만으로는 BR의 발현이 유도되지 않았으며, Ndk와 함께 flagella가 필요함을 발견하였다. 이러한 결과는 기존에 보고된 주요 pathogen-associated molecular patterns (PAMPs)인 flagella와 더불어 감염대응에 관여하는 Ndk를 발굴한 의미가 있으며, 녹농균에 의한 질병기전을 이해하는데 도움을 줄 수 있다.

• 생명과학회지
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• 제17권2호통권82호
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• pp.235-240
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• 2007

본 연구는 Affymetrix Arabidopsis DNA chip을 이용하여 비 병원성 인자인 AvrRpt2 단백질에 의해서 특이적으로 전사 과정이 조절되는 애기장대 유전자들을 분리하고 병 저항성 방어체계와 관련한 이들 유전자들의 기능 분석을 시도하였다. 그 중에서 먼저 식물 호르몬인 ethylene의 신호 조절에 관여하는 ERFs (ethylene-responsive element binding factors) 전사조절 유전자 family 중에서 Bla subfamily 그룹으로 알려져 있는 AtERF11 유전자의 병 저항성 관련 기능을 규명하였다. 저항성 유전자 RPS2가 없는 경우에는 비 병원성 인자인 AvrRpt2 단백질은 기주 식물체내의 기초 병저항성을 감소시키고 병원성 세균의 증식을 향상시켜서 병증을 증대시키는 effector로 작용한다는 기존의 연구결과와 유사하게, 저항성 유전자 RPS2가 없는 조건에서 AtERF11 유전자의 발현이 AvrRpt2 단백질의 작용에 의해서 특이적으로 감소되는 것을 확인하였다. 이러한 결과를 바탕으로 AtERF11 유전자는 식물체의 병 저항성 방어기작에 있어서 positive regulator로서 작용하기 때문에 effector로 작용하는 AvrRpt2 단백질에 의해서 조절되는 것으로 추측하였다. 본 가설을 증명하기 위해 AtERF11의 발현을 증폭시킨 애기장대 형질전화체를 제작하고 P. syringae pv. tomato DC 3000에 대한 병저항성을 실험하였다. AtERF11 유전자가 대량 발현하는 형질전화 된 애기장대에서는 야생종에 비해 대략 100배 이상 세균의 증식이 억제되는 강력한 병저항성을 가진다는 것을 검증하였다.

• 대한의생명과학회지
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• 제24권1호
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• pp.1-8
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• 2018

${\mu}MT$ knockout mice are genetically deficient in the transmembrane domain of mu chain of the immunoglobulin M (IgM) heavy chain, resulting in the absence of mature B cells. ${\mu}MT$ knockout mice is an in vivo model system used to clarify the role of B cells in various diseases. Enteropathogenic Escherichia coli (EPEC) induces acute and chronic diarrheal disease, especially in children of developing countries. The formation of attaching and effacing (A/E) lesion is a prominent pathogenic factor in the intestinal epithelium of EPEC infection. The A/E lesion is modulated by genes located on the pathogenic island locus of enterocyte effacement (LEE) which encode a type III secretion system (T3SS) and A/E lesion-related effector proteins. Citrobacter rodentium is a murine pathogen utilized in studying the pathogenic mechanisms of EPEC in human infections. Citrobacter rodentium produce A/E lesion to attach to intestinal epithelium, thus providing a murine model pathogen to study EPEC. Several studies have investigated the pathogenesis of Citrobacter rodentium in the ${\mu}MT$ knockout mice. In this review, we introduce the ${\mu}MT$ murine model in the context of C. rodentium pathogenesis and describe in detail the role of B cells and antibodies in this disease.

• The Plant Pathology Journal
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• 제36권1호
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• pp.29-42
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• 2020

Acidovorax citrulli causes bacterial fruit blotch in Cucurbitaceae, including watermelon. Although A. citrulli is a seed-borne pathogen, it can cause diverse symptoms in other plant organs like leaves, stems and fruits. To determine the infection routes of A. citrulli, we examined the virulence of six isolates (Ac0, Ac1, Ac2, Ac4, Ac8, and Ac11) on watermelon using several inoculation methods. Among six isolates, DNA polymorphism reveals that three isolates Ac0, Ac1, and Ac4 belong to Clonal Complex (CC) group II and the others do CC group I. Ac0, Ac4, and Ac8 isolates efficiently infected seeds during germination in soil, and Ac0 and Ac4 also infected the roots of watermelon seedlings wounded prior to inoculation. Infection through leaves was successful only by three isolates belonging to CC group II, and two of these also infected the mature watermelon fruits. Ac2 did not cause the disease in all assays. Interestingly, three putative type III effectors (Aave_2166, Aave_2708, and Aave_3062) with intact forms were only found in CC group II. Overall, our results indicate that A. citrulli can infect watermelons through diverse routes, and the CC grouping of A. citrulli was only correlated with virulence in leaf infection assays.