• 한국미생물·생명공학회지
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• 제47권4호
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• pp.596-602
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• 2019

본 연구는 독도에서 서식하는 자생식물인 번행초와 번행초의 근권에서 미생물들을 분리하였다. 분리 균의 식물생장 촉진 특성을 확인하였으며, 식물 병에 대한 저항성을 유도효과를 가진 균 중 범용성이 좋은 바실러스 속 세균에 초점을 두어 실험을 진행하였다. 번행초의 분리 균들은 근권환경에 52종, 식물체 내생 환경에서 51종, 식물체 표면에서 35종으로 총 138종의 분리 균이 확보되었다. 분리 균의 식물생장촉진특징을 확인하여 보기 위하여, 식물 성장에 필요한 난용성인 가용화와 철의 결합에 사용되는 siderophore의 생산능, 식물생장호르몬인 옥신 생산능을 확인하여 각각의 비율을 확인하였고, 3가지 특성을 모두 가진 균의 비율을 확인하였다. 또한 분리 균을 담배에 처리하여 병원균에 대한 유도전신저항성을 확인하였고, 그 중 효과가 좋았던 균 35종을 부분 동정한 결과, 바실러스 속은 KUDC6588, KUDC6597, KUDC6606, KUDC6614, KUDC6615, KUDC6619로 나타났다. 6종의 바실러스 속 세균들은 모두 저항성 향상에 좋은 효과를 보였으며, 특히 KUDC6619의 경우 현재 화학항생물질인 BTH와도 비슷한 효과를 보였다. KUDC6619는 대표적인 식용작물인 고추에서도 유도전신저항성의 향상에 대한 좋은 결과를 나타내었다. 따라서 사람과 동물에 대한 안전성, 식물 병원성 등 다양한 테스트를 진행한 후, 안정성이 확보된다면, KUDC6619는 식물의 ISR을 야기하는 생물농약 으로서의 높은 산업적 가치가 있을 것으로 보인다.

• Journal of Microbiology and Biotechnology
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• 제23권8호
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• pp.1159-1166
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• 2013

Orientia tsutsugamushi, a gram-negative bacterium, causes severe acute febrile illness in humans. Despite this danger, the route of infection, infectivity, and protective mechanisms of the host's immune response to O. tsutsugamushi are unclear. Dendritic cells (DCs) are one of the most important cell types in bridging the innate and adaptive immune responses. In this study, we observed that O. tsutsugamushi infects and replicates in monocyte-derived DCs (MODCs). During infection and replication, the expressions of the cytokines IL-12 and TNF-${\alpha}$, as well as the co-stimulatory molecules CD80, CD83, CD86, and CD40, were increased in MODCs. When O. tsutsugamushi-treated MODCs were co-cultured with autologous $CD4^+$ T cells, they enhanced production of IFN-${\gamma}$, a major Th1 cytokine. Collectively, our results show that O. tsutsugamushi can replicate in MODCs and can simultaneously induce MODC maturation and increase proinflammatory cytokine levels in MODCs that subsequently activate $CD4^+$ T cells.

• Journal of Microbiology and Biotechnology
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• 제27권8호
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• pp.1529-1538
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• 2017

Klebsiella pneumoniae is an opportunistic and clinically significant emerging pathogen. We investigated the relative roles of Toll-like receptor (TLR) 2 and TLR4 in initiating host defenses against K. pneumoniae. TLR2 knockout (KO), TLR4 KO, TLR2/4 double KO (DKO), and wild-type (WT) mice were inoculated with K. pneumoniae. Mice in each group were sacrificed after either 12 or 24h, and the lungs, liver, and blood were harvested to enumerate bacterial colony-forming units (CFU). Cytokine and chemokine levels were analyzed using enzyme-linked immunosorbent assay and real-time PCR, and pneumonia severity was determined by histopathological analysis. Survival was significantly shortened in TLR4 KO and TLR2/4 DKO mice compared with that of WT mice after infection with $5{\times}10^3CFU$. TLR2 KO mice were more susceptible to infection than WT mice after exposure to a higher infectious dose. Bacterial burdens in the lungs and liver were significantly higher in TLR2/4 DKO mice than in WT mice. Serum $TNF-{\alpha}$, MCP-1, MIP-2, and nitric oxide levels were significantly decreased in TLR2/4 DKO mice relative to those in WT mice, and TLR2/4 DKO mice showed significantly decreased levels of $TNF-{\alpha}$, IL-6, MCP-1, and inducible nitric oxide synthase mRNA in the lung compared with those in WT mice. Collectively, these data indicate that TLR2/4 DKO mice were more susceptible to K. pneumoniae infection than single TLR2 KO and TLR4 KO mice. These results suggest that TLR2 and TLR4 play cooperative roles in lung innate immune responses and bacterial dissemination, resulting in systemic inflammation during K. pneumoniae infection.

• 한국축산식품학회지
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• 제24권1호
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• pp.86-91
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• 2004

최근 들어 건강에 대한 관심이 증대되면서 건강증진과 관련된 많은 probiotics 균주들의 선별에 대한 연구가 계속해서 진행되고 있다. L. acidophilus를 포함하는 probiotics 중 장 상피세포에 부착력이 우수한 균종들이 보고되고 있으며 이들은 병원성 미생물을 예방하는데 중요한 역할을 할 수 있을 것으로 생각된다. 본 실험에서는 HT-29 cell을 대상으로 다양한 근원으로부터 분리된 L. acidophilus의 부착능력을 측정하였다. 부착능이 우수하다고 보고된 LGG를 대조구로 부착능력을 평가하였을 때 5종의 L. acidophilus 모두 LGG와 유사한 부착능력을 나타내었으며 L. acidophilus A4의 경우 가장 높은 1.2${\times}$$10^{7}$ cfu/ml의 부착능력을 보였다. 따라서 장 상피세포에 대한 부착능력이 host에 대한 특이성과는 높은 상관관계가 없는 것으로 생각된다. 또한 부착된 유산균을 3분씩 3회 연속 wash-out을 실시하였을 때 모두 $10^{5}$ cfu/mL 이상의 부착능력을 유지하였다. 그러나 이러한 probiotics의 부착능력과 세포표면 소수성의 상관관계를 관찰하였을 때 어떠한 유의성도 나타나지 않았다. 따라서 본 실험에서 사용된 5종의 L. acidophilus의 경우 세포표면 소수성에 의해 부착능력이 나타나는 것이 아니라 다른 기작에 의해 부착능력이 나타나는 것으로 생각된다. 그리고 5종의 L. acidophilus를 대상으로 EHEC ATCC 43889의 장 상피세포 부착억제능력을 측정하였을 때 5종 모두 대조구와 비교했을 때 EHEC의 부착을 2 log 수준으로 억제하는 것으로 나타났다. 명확하지는 않지만 이는 일부 유산균주의 부착능력과 관계가 있는 것으로 생각되며 또한 유산균이 생성하는 발효산물이나 세포표면 단백질에 의해 영향을 받는 것으로 생각된다.다.

• 아시안잔디학회지
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• 제19권2호
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• pp.85-94
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• 2005

위에서 골프장의 안양 중지 이병 잎에서 분리한 병원균인 달라스팟 유사 병원균을 분리 동정하였다. 2000년도 국내에 처음 보고된 이후 현재까지 뚜렷하게 진전된 연구가 보고 되지 않아 향후 사전 예방과 발생시 방제 법을 강구하기 위함과 아울러 코스관리자의 면밀한 관심을 유도하기 위하여 병원균 분리, 동정 및 특성을 한지형 잔디(Agyostis palustris Huds. cv Penncross)에서 발생하는 달라스팟 병원균과 비교 실험을 실시하였다. 1. 기존에 알려진 것처럼 Sclerotinia homoeocarpa 에서 보이는 온도에 대한 민감도를 새로운 병원성 Scz1 균주에서도 볼 수있어 특정온도에서의 생장억제는 안양 중지 달라스팟 병의 발병하는 시기뿐만 아니라 병방제관리에 도움이 될 것으로 생각된다. 2. 병원균 균사 특성에서 전자현미경사진으로는 구별하기 어려웠으나, PDA배지상에서의 Scz1와 Scz2 색상은 동일한 반면 Scb1균사색상과는 차이가 남으로 향후 간단하게 균사색상으로 식별이 용이 할 것이다. 3. 실험실상에서 병원균의 약제 민감도 측정결과는 이프로디온과 프로피코나졸 약제가 우수하였다. 4. 병 접종 실험을 통하여 분리된Sczl 균주가 안양 중지에 대한 기주 특이성을 보임으로 조이시아 달라스팟의 주요 병원균으로 밝혀졌다. 5. Scz1의 병원성은 안양 중지에 대한 기주 특이성이 높은 것으로 밝혀졌다.

• Asian Pacific Journal of Cancer Prevention
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• 제13권4호
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• pp.1247-1251
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• 2012

Background: Helicobacter pylori is an important gastrointestinal pathogen related to the development of not only atrophic gastritis and peptic ulcer, but also gastric cancer. Human leukocyte antigens (HLA) may play particular roles in host immune responses to bacterial antigens. This study aimed to investigate the association between HLA-DQA1 and DQB1 genotypes and haplotypes vs H. pylori infection in an Indonesian population. Methods: We selected 294 healthy participants in Mataram, Lombok Island, Indonesia. H. pylori infection was determined by urea breath test (UBT). We analyzed HLA-DQA1 and DQB1 genotypes by PCR-RFLP and constructed haplotypes of HLA-DQA1 and DQB1 genes. Multiple comparisons were conducted according to the Bonferroni method. Results: The H. pylori infection rate was 11.2% in this Indonesian population. The DQB1*0401 genotype was noted to be associated with a high risk of H. pylori infection, compared with the DQB1*0301 genotype. None of the HLA-DQA1 or DQB1 haplotypes were related to the risk of H. pylori infection. Conclusions: The study suggests that HLADQB1 genes play important roles in H. pylori infection, but there was no statistically significant association between HLA-DQA1 or DQB1 haplotypes and H.pylori infection in our Lombok Indonesian population.

• 한국식물병리학회지
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• 제3권3호
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• pp.210-216
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• 1987

미기상 상태에 의하여 벼 도열병을 예찰하기 위한 전산화 예찰모델을 개발하여 그 정확도를 전산모델을 수록한 현지위치형 소형 전산기로서 1984년과 1985년에 걸쳐 포장에서 시험하였다. 건전지 작동형 소형 전산기는 벼 군락내 온도, 습도, 잎이 젖어있는 시간을 계속적으로 측정하여 그 상태를 도열병 발생가능성과 관련하여 평가해서 매일의 병발생가능성 수치(BUS)로 표현한다. 매일의 BUS의 누적치(CBUS)와 두 이병성 품종, M-201과 Brazos에서의 도열병 진전정도와는 밀접한 상관이 있었다. 발병엽율의 logit 치를 CBUS로 회귀하였을 때 평균 결정계수$(R^2)$는 품종과 실험한 해에 따라 $71\%\~91\%$였으며 이것은 시간을 독립변수로 사용하였을 때의 결정계수$61\%\~79\%$에 비하여 현저히 높았다. 결정계수는 M-201에 비하여 생육후기에 포장저항성을 보인 Brazos에서 더 낮았다. 이상의 결과, 현예찰 모델은 실제로 사용가능성이 있지만 앞으로 기주의 저항성이나 병원균 집단의 병원성과 관련한 변수들을 기상환경의 변수와 함께 통합함에 의하여 보다 정확한 예찰모델로 개발할 수 있으리라 생각한다.

• BMB Reports
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• 제49권10호
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• pp.554-559
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• 2016

Mycobacterium abscessus, a member of the group of non-tuberculous mycobacteria, has been identified as an emerging pulmonary pathogen in humans. However, little is known about the protective immune response of antigen-presenting cells, such as dendritic cells (DCs), which guard against M. abscessus infection. The M. abscessus gene MAB1843 encodes ᴅ-alanyl-ᴅ-alanine dipeptidase, which catalyzes the hydrolysis of ᴅ-alanyl-ᴅ-alanine dipeptide. We investigated whether MAB1843 is able to interact with DCs to enhance the effectiveness of the host's immune response. MAB1843 was found to induce DC maturation via toll-like receptor 4 and its downstream signaling pathways, such as the mitogen-activated protein kinase and nuclear factor kappa B pathways. In addition, MAB1843-treated DCs stimulated the proliferation of T cells and promoted Th1 polarization. Our results indicate that MAB1843 could potentially regulate the immune response to M. abscessus, making it important in the development of an effective vaccine against this mycobacterium.

• The Plant Pathology Journal
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• 제18권5호
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• pp.293-299
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• 2002

A survey of Fusarium wilt of perilla was conducted in 12 locations in Korea from 1999 to 2001. The disease occurred in 74 out of 187 fields in the 12 locations surveyed, and incidence of the disease reached up to 30% at its maximum in some perilla fields in Seosan and Dangjin. Incidence of the disease in the other locations ranged from 0.2 to 20%. A total of 327 isolates of Fusarium spp. were obtained from stems and roots of the diseased perilla plants. The isolates were identified based on their morphological characteristics. Out of the 327 isolates of Fusarium, 277 isolates from 12 locations were identified as F. oxysporum, 11 isolates from three locations as F. solani,17 isolates from two locations as F. equiseti, 4 isolates from one location as F. avenaceum and 6 isolates from one location as F. subglutinans. The other 12 isolates of Fusarium from four locations were unidentified. Twelve isolates of F. oxysporum and two isolates each of the other Fusarium spp. were tested for their pathogenicity to five cultivars of perilla. Seven isolates of F. oxysporum were strongly pathogenic to some perilla cultivars, but the other five isolates were weakly or not pathogenic. One isolate of F. solani was strongly pathogenic to all the perilla cultivars tested, but another isolate was not pathogenic. All the isolates of F. equiseti, F. avenaceum, and F. Subglutinans tested were not pathogenic to any of the perilla cultivars tested. Symptoms on the perilla plants induced by artificial inoculation with strongly pathogenic isolates of F. oxysporum and F. solani appeared as wilt, stem blight, and root yet, which were similar to those observed in the fields. The isolates which induced symptoms by artificial inoculation were re-isolated from the lesions of the perilla plants inoculated. All the isolates of F. oxysporum tested were not pathogenic to eight other crops inoculated. Results of this study reveal that F. oxysporum is the main pathogen of perilla wilt and that it is host specific to perilla. forma specialis of F. oxysporum causing wilt of perilla is proposed as perillae.

• 한국균학회소식:학술대회논문집
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• 한국균학회 2015년도 추계학술대회 및 정기총회
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• pp.41-41
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• 2015

Oomycetes belong to the kingdom Straminipila, a remarkably diverse group which includes brown algae and planktonic diatoms, although they have previously been classified under the kingdom Fungi. These organisms have evolved both saprophytic and pathogenic lifestyles, and more than 60% of the known species are pathogens on plants, the majority of which are classified into the order Peronosporales (includes downy mildews, Phytophthora, and Pythium). Recent phylogenetic investigations based on DNA sequences have revealed that the diversity of oomycetes has been largely underestimated. Although morphology is the most valuable criterion for their identification and diversity, morphological species identification is time-consuming and in some groups very difficult, especially for non-taxonomists. DNA barcoding is a fast and reliable tool for identification of species, enabling us to unravel the diversity and distribution of oomycetes. Accurate species determination of plant pathogens is a prerequisite for their control and quarantine, and further for assessing their potential threat to crops. The mitochondrial cox2 gene has been widely used for identification, taxonomy and phylogeny of various oomycete groups. However, recently the cox1 gene was proposed as a DNA barcode marker instead, together with ITS rDNA. To determine which out of cox1 or cox2 is best suited as universal oomycete barcode, we compared these two genes in terms of (1) PCR efficiency for 31 representative genera, as well as for historic herbarium specimens, and (2) in terms of sequence polymorphism, intra- and interspecific divergence. The primer sets for cox2 successfully amplified all oomycete genera tested, while cox1 failed to amplify three genera. In addition, cox2 exhibited higher PCR efficiency for historic herbarium specimens, providing easier access to barcoding type material. In addition, cox2 yielded higher species identification success, with higher interspecific and lower intraspecific divergences than cox1. Therefore, cox2 is suggested as a partner DNA barcode along with ITS rDNA instead of cox1. Including the two barcoding markers, ITS rDNA and cox2 mtDNA, the multi-locus phylogenetic analyses were performed to resolve two complex clades, Bremia lactucae (lettuce downy mildew) and Peronospora effuse (spinach downy mildew) at the species level and to infer evolutionary relationships within them. The approaches discriminated all currently accepted species and revealed several previously unrecognized lineages, which are specific to a host genus or species. The sequence polymorphisms were useful to develop a real-time quantitative PCR (qPCR) assay for detection of airborne inoculum of B. lactucae and P. effusa. Specificity tests revealed that the qPCR assay is specific for detection of each species. This assay is sensitive, enabling detection of very low levels of inoculum that may be present in the field. Early detection of the pathogen, coupled with knowledge of other factors that favor downy mildew outbreaks, may enable disease forecasting for judicious timing of fungicide applications.