• Mycobiology
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• 제42권4호
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• pp.412-415
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• 2014

Alternaria from different Allium plants was characterized by multilocus sequence analysis. Based on sequences of the ${\beta}$-tubulin (BT2b), the Alternaria allergen a1 (Alt a1), and the RNA polymerase II second largest subunit (RPB2) genes and phylogenetic data analysis, isolates were divided into two groups. The two groups were identical to representative isolates of A. porri (EGS48-147) and A. vanuatuensis (EGS45-018). The conidial characteristics and pathogenicity of A. vanuatuensis also well supported the molecular characteristics. This is the first record of A. vanuatuensis E. G. Simmons & C. F. Hill from Korea and China.

• Journal of Microbiology
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• 제43권spc1호
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• pp.85-92
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• 2005

An early step in the pathogenesis of non-typhoidal Salmonella species is the ability to penetrate the intestinal epithelial monolayer. This process of cell invasion requires the production and transport of secreted effector proteins by a type III secretion apparatus encoded in Salmonella pathogenicity island I (SPI-1). The control of invasion involves a number of genetic regulators and environmental stimuli in complex relationships. SPI-1 itself encodes several transcriptional regulators (HilA, HilD, HilC, and InvF) with overlapping sets of target genes. These regulators are, in turn, controlled by both positive and regulators outside SPI-1, including the two-component regulators BarA/SirA and PhoP/Q, and the csr post-transcriptional control system. Additionally, several environmental conditions are known to regulate invasion, including pH, osmolarity, oxygen tension, bile, $Mg^{2+}$ concentration, and short chain fatty acids. This review will discuss the current understanding of invasion control, with emphasis on the interaction of environmental factors with genetic regulators that leads to productive infection.

• The Plant Pathology Journal
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• 제18권2호
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• pp.57-62
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• 2002

In vivo expression technology (IVET) has been developed to study bacterial gene expression in Salmonella typhimurium during host infection. The expression of selected genes by IVET has been elevated in vivo but not in vitro. The selected genes turned out to be important for bacterial virulence and/or pathogenicity. IVET depends on a synthetic operon with a promoterless transcriptional fusion between a selection marker gene and a reporter gene. The IVET approach has been successfully adapted in other bacterial pathogens and plant-associated bacteria using different selection markers. Pseudomonas putida suppresses citrus root rot caused by Phytophthora parasitica and enhances citrus seedling growth. The WET strategy was adapted based on a transcriptional fusion, pyrBC'-lacZ, in P. putida to study the bacterial traits important far biocontrol activities. Several genes appeared to be induced on P. parasitica hyphae and were found to be related with metabolism and regulation of gene expression. It is likely that the biocontrol strain took a metabolic advantage from the plant pathogenic fungus and then suppressed citrus root rot effectively. The result was parallel with those from the adaptation of IVET in P. fluorescens, a plant growth promoting rhizobacteria (PGPR). Interestingly, genes encoding components for type III secretion system have been identified as rhizosphere-induced genes in the PGPR strain. The type III secretion system may play a certain role during interaction with its counterpart plants. Application of IVET has been demonstrated in a wide range of bacteria. It is an important strategy to genetically understand complicated bacterial traits in the environment.

• Journal of Microbiology and Biotechnology
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• 제21권12호
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• pp.1228-1235
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• 2011

We compared the gene expression among four clinical and five environmental V. vulnificus isolates, using a cDNA microarray containing 131 genes possibly associated with pathogenicity, transport, signal transduction, and gene regulations in the pathogen. cDNAs from total RNAs of these isolates were hybridized into the cDNA microarray using the cDNA of the wild-type strain MO6-24/O as a reference. We focused on selecting differentially expressed (DE) genes between clinical and environmental isolates using a modified t-statistic. We could detect two statistically significant DE genes between virulent isolates and less-virulent isolates with a marginal statistical significance (p-value of 0.008). These were genes putatively encoding pilin and adenlyate cylase. Real time-PCR confirmed that these two selected genes transcribed in significantly higher levels in virulent isolates than in less-virulent isolates. Mutants with lesions in the gene encoding pilin showed significantly higher $LD_{50}$ values than that of wild type.

• The Plant Pathology Journal
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• 제30권4호
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• pp.367-374
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• 2014

Genomes contain a large number of unique genes which have not been found in other species. Although the origin of such "orphan" genes remains unclear, they are thought to be involved in species-specific adaptive processes. Here, we analyzed seven orphan genes (MoSPC1 to MoSPC7) prioritized based on in planta expressed sequence tag data in the rice blast fungus, Magnaporthe oryzae. Expression analysis using qRT-PCR confirmed the expression of four genes (MoSPC1, MoSPC2, MoSPC3 and MoSPC7) during plant infection. However, individual deletion mutants of these four genes did not differ from the wild-type strain for all phenotypes examined, including pathogenicity. The length, GC contents, codon adaptation index and expression during mycelial growth of the four genes suggest that these genes formed during the evolutionary history of M. oryzae. Synteny analyses using closely related fungal species corroborated the notion that these genes evolved de novo in the M. oryzae genome. In this report, we discuss our inability to detect phenotypic changes in the four deletion mutants. Based on these results, the four orphan genes may be products of de novo gene birth processes, and their adaptive potential is in the course of being tested for retention or extinction through natural selection.

• Journal of Microbiology and Biotechnology
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• 제19권3호
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• pp.238-249
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• 2009

The genus Listeria consists of six closely related species and forms three phylogenetic groups: L. monocytogenes-L. innocua, L. ivanovii-L. seeligeri-L. welshimeri, and L. grayi. In this report, we attempted to examine the evolutionary relationship in the L. monocytogenes-L. innocua group by probing the nucleotide sequences of 23S rRNA and 16S rRNA, and the gene clusters lmo0029-lmo0042, ascB-dapE, rplS-infC, and prs-ldh in L. monocytogenes serovars 1/2a, 4a, and 4b, and L. innocua. Additionally, we assessed the status of L. monocytogenes-specific inlA and inlB genes and 10 L. innocua-specific genes in these species/serovars, together with phenotypic characterization by using in vivo and in vitro procedures. The results indicate that L. monocytogenes serovar 4a strains are genetically similar to L. innocua in the lmo0035-lmo0042, ascB-dapE, and rplS-infC regions and also possess L. innocua-specific genes lin0372 and lin1073. Furthermore, both L. monocytogenes serovar 4a and L. innocua exhibit impaired intercellular spread ability and negligible pathogenicity in mouse model. On the other hand, despite resembling L. monocytogenes serovars 1/2a and 4b in having a nearly identical virulence gene cluster, and inlA and inlB genes, these serovar 4a strains differ from serovars 1/2a and 4b by harboring notably altered actA and plcB genes, displaying strong phospholipase activity and subdued in vivo and in vitro virulence. Thus, by possessing many genes common to L. monocytogenes serovars 1/2a and 4b, and sharing many similar gene deletions with L. innocua, L. monocytogenes serovar 4a represents a possible evolutionary intermediate between L. monocytogenes serovars 1/2a and 4b and L. innocua.

• Journal of Microbiology and Biotechnology
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• 제26권1호
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• pp.197-206
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• 2016

Listeria monocytogenes is a foodborne pathogen of considerable genetic diversity with varying pathogenicity. Initially, we found that the strain M7 was far less pathogenic than the strain Lm850658 though both are serovar 4a strains belonging to the lineage III. Comparative genomic approaches were then attempted to decipher the genetic basis that might govern the strain-dependent pathotypes. There are 2,761 coding sequences of 100% nucleotide identity between the two strains, accounting for 95.7% of the total genes in Lm850658 and 92.7% in M7. Lm850658 contains 33 specific genes, including a novel 20K prophage whereas strain M7 has 130 specific genes, including two large prophages (38K and 44K). To examine the roles of these specific prophages in pathogenicity, the 20K and 38K prophages were deleted from their respective strains. There were virtually no differences of pathogenicity between the deletion mutants and their parent strains, although some putative virulent factors like VirB4 are present in the 20K region or holin-lysin in the 38K region. In silico PCR analysis of 29 listeria genomes show that only strain SLCC2540 has the same 18 bp integration hotspot as Lm850658, whereas the sequence identity of their 20K prophages is very low (21.3%). The 38K and 44K prophages are located in two other different hotspots and are conserved in low virulent strains M7, HCC23, and L99. In conclusion, the 20K and 38K prophages of L. monocytogenes serovar 4a strains Lm850658 and M7 are not related to virulence but contribute to genetic diversity.

• 농약과학회지
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• 제12권3호
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• pp.283-290
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• 2008

베큘로바이러스는 일부 나비목 해충을 대상으로 방제하는 데 사용되고 있다. 그러나 화학농약에 비해 느린 살충효과 및 좁은 적용 해충으로 응용 범위에 한계를 갖고 있다. 본 연구는 이러한 한계를 극복하고자 곤충의 면역억제을 통해 바이러스 병원력을 제고시킬 수 있는 기술을 소개한다. 폴리드나바이러스는 일부 맵시벌 및 고치벌에 공생하는 곤충 DNA 바이러스 분류군이다. 프루텔고치벌(Cotesia plutellae) 유래 CpBV(Cotesia plutellae bracovirus)는 브라코바이러스에 속한 폴리드나바이러스로서 면역어제를 발휘하는 여러 유전자를 함유하고 있다. 이 가운데 7개의 CpBV유전자를 선발하고 이를 야생형Autographa California multiple nucleopolyhedrovirus(AcNPV)에 재조합하였다. 이들 재조합 베큘로바이러스를 이용하여 파밤나방(Spodoptera exigua)과 배추좀나방(Plutella xylostella)을 대상으로 생물 검정한 결과, 이들 대부분은 야생형의 바이러스와 유사하거나 우수한 살충력을 나타냈다. 특히 CpBV-ELP를 포함한 재조합 베큘로바이러스가 대조바이러스에 비해 살충시간을 약 2 일 이상단축시킴으로 가장 우수하였다. 이 재조합 베큘로바이러스는 농도에 따른 살충력증가와 배추를 가해하는 파밤나방을 대상으로 한 바이러스 살포 처리가 뚜렷한 방제효과를 나타내어 현장 적용 가능성을 제시하였다. 또한 본 연구는 이 재조합 바이러스의 살충력 제고 현상을 CpBV-ELP의 항바이러스 기작 억제라는 측면에서 고찰했다.

• 한국융합학회논문지
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• 제6권5호
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• pp.77-84
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• 2015

본 연구는 항균제에 내성을 보이는 대장균의 특성을 알아보기 위해 설사환자에서 분리된 대장균에 대한 항균제 감수성 및 병원성 인자의 상관성을 분자융합적 기술을 통해 조사하였다. 분리한 대장균의 항균제 내성은 60주에서 ESBL(extendede spectrum ${\beta}$-lactamase) positive균주가 8주이고, negative균주는 52주였다. ESBL 양성 8주 중 2주는 병원성 유전자가 검출되지 않았으며, stb(3주), flich7(1주), flich7-eae(2주)로 나타났다. ESBL 음성 52주 중 26주는 병원성 유전자가 검출되지 않았고, stx1(3주), stb(10주), flich7 및 eae(각 2주), stx1-flich7(2주), stx1-stb(4주), flich7-stb(2주), flich7-stb-eae(1주)이었다. 결론적으로 항균제 내성이 증가하는 시대에 분자 융합적 관점에서 독력 유전자의 분포와 항균제 내성과의 관계는 적게 나타났으나, 향후 다양한 독력 유전자의 분석을 통한 융합기술연구가 이루어진다면 보다 정확한 병원성 인자를 추정할 수 있을 것으로 사료된다.

• 생명과학회지
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• 제23권1호
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• pp.8-14
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• 2013

고추 탄저병균의 포자 발아 단계에서 발현되는 유전자를 파악하기 위해 포자 발아단계cDNA library를 제작하고, 임의로 선택된 cDNA clone들에 대한 EST sequencing을 실시하였다. 총 983개 EST를 확보하여 contig assembly를 실시한 결과, 197개 contigs와 267개 singletons으로 조합되어, 최종적으로 464개의 유전자를 동정하였다. 464개 유전자 서열에서 유추한 아미노산 서열을 이용한 상동유전자 검색을 통해 절반의 유전자가 GenBank에 기존 등록된 유전자와 유의성 있는 유사성을 보였다. 가장 높은 빈도로 발현된 유전자는 elongation factor, histone protein, ATP synthease, 14-3-3 protein, clock controlled protein을 암호화하는 유전자들이었다. 그리고 고추 탄저병균의 세포 발달과정에 관여 하는것으로 추정되는 GTP-binding protein, MAP kinase, transaldolase, ABC transporter 유전자들도 검출되었다. 또한 고추탄저병균의 병원성에 영향을 미치는 것으로 파악되는 ATP citrate lyase, CAP20, manganese-superoxide dismutase 유전자들도 검출되어, EST sequencing 을 통한 세포 발달 단계 발현 유전자 탐색이 효과적임을 알 수 있었다.