• Journal of Periodontal and Implant Science
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• 제48권1호
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• pp.12-21
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• 2018

Purpose: The goal of this study was to develop and validate a standardized in vitro pathogenic biofilm attached onto saliva-coated surfaces. Methods: Fusobacterium nucleatum (F. nucleatum) and Porphyromonas gingivalis (P. gingivalis) strains were grown under anaerobic conditions as single species and in dual-species cultures. Initially, the bacterial biomass was evaluated at 24 and 48 hours to determine the optimal timing for the adhesion phase onto saliva-coated polystyrene surfaces. Thereafter, biofilm development was assessed over time by crystal violet staining and scanning electron microscopy. Results: The data showed no significant difference in the overall biomass after 48 hours for P. gingivalis in single- and dual-species conditions. After adhesion, P. gingivalis in single- and dual-species biofilms accumulated a substantially higher biomass after 7 days of incubation than after 3 days, but no significant difference was found between 5 and 7 days. Although the biomass of the F. nucleatum biofilm was higher at 3 days, no difference was found at 3, 5, or 7 days of incubation. Conclusions: Polystyrene substrates from well plates work as a standard surface and provide reproducible results for in vitro biofilm models. Our biofilm model could serve as a reference point for studies investigating biofilms on different surfaces.

• 한국응용곤충학회지
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• 제23권3호
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• pp.147-152
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• 1984

벼 흰잎마름병에 대한 저항성품종 육성된 보급에 활용하고자 1979년부터 1983년까지 5개년에 걸쳐 병원세균의 균형분포를 조사한 결과, 1. 전국의 균형분포비율은 조사된 625균주중 I 균군이 $77.3\%$, II 균군 $13.3\%$, III 균군 $8.6\%$, IV 균군 $0.5\%$, V 균군 $0.3\%$로 I 균군이 대부분 점유하였고, 품종 피해범위가 넓은 IV균군의 분포가 처음으로 확인되었다. 2. 각 도별 균형분포로서는 전라남도에서는 II균군과 III균군의 분포비율이 타도에 비해 매우 높았다. 3. 균형별로 분리된 품종에서는 대부분 밀양 23호품종군에서 각 균군이 분리되었고, 유신품종군에서는 II 균군과 III균군이, 통일품종군에선 III 균군이 많이 분리되었다. 4. 한국에서 본 병의 최초 발병지이며 매년 발병 상습지인 전라남도 해남군내의 균형분포를 조사한 결과 1 균군 $12.5\%$, II 균군 $50.8\%$, III 균군 $35.0\%$, IV 균군 $1.7\%$로서 전국의 균형분포화 비교할 때 II 균군과 III 균군에 분포비율이 특히 높았다.

• 한국응용곤충학회지
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• 제17권1호
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• pp.15-22
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• 1978

1. "Kresek" 유발균주(K균주)는 품종에 따라서 발현에 차이가 있었으며 지상부 또는 지하부에 접종하여도 "Kresek"을 유발시킬 수 있었으나 대조균주(N균주)는 전연 유발되지 않았다. 2. 엽백의 도관직경은 밀양 23이 유신이나 통일보다 현저히 작았으며 이들간에 고도의 통계적인 유의차가 인정되었다. 3. 밀양 23의 즙액에서 K균주들은 N균주들보다 세균의 증식이 왕성하였으며 통일에서는 균주들간에 증식의 차이가 없었다. 4. 밀양 23의 즙액친서는 K균주의 Dead phase가 정종 9일째부터 N균주는 4일째부터 시작되었으며 통일에서는 모두 3일째부터 시작되었다. 5. 밀양 23즙액의 경우 pH 3.0-4.0 범위에서 다량의 침전물이 형성되었으나 동일의 증액에서는 극히 소량의 침전물을 관찰할 수가 있었다.

• 대한약침학회지
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• 제19권3호
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• pp.225-230
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• 2016

Objectives: Mellitine, a major component of bee venom (BV, Apis mellifera), is more active against gram positive than gram negative bacteria. Moreover, BV has been reported to have multiple effects, including antibacterial, antivirus, and anti-inflammation effects, in various types of cells. In addition, wasp venom has been reported to have antibacterial properties. The aim of this study was to evaluate the antibacterial activity of BV against selected gram positive and gram negative bacterial strains of medical importance. Methods: This investigation was set up to evaluate the antibacterial activity of BV against six grams positive and gram negative bacteria, including Staphylococcus aureus (S. aureus), Salmonella typhimurium, Escherichia coli (E. coli) O157:H7, Pseudomonas aeruginosa, Burkholderia mallei and Burkholderia pseudomallei. Three concentrations of crude BV and standard antibiotic (gentamicin) disks as positive controls were tested by using the disc diffusion method. Results: BV was found to have a significant antibacterial effect against E. coli, S. aureus, and Salmonella typhyimurium in all three concentrations tested. However, BV had no noticeable effect on other tested bacteria for any of the three doses tested. Conclusion: The results of the current study indicate that BV inhibits the growth and survival of bacterial strains and that BV can be used as a complementary antimicrobial agent against pathogenic bacteria. BV lacked the effective proteins necessary for it to exhibit antibacterial activity for some specific strains while being very effective against other specific strains. Thus, one may conclude, that Apis mellifera venom may have a specific mechanism that allows it to have an antibacterial effect on certain susceptible bacteria, but that mechanism is not well understood.

• 미생물학회지
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• 제54권2호
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• pp.149-151
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• 2018

Clostridium perfringens는 그람 양성, 막대 모양, 혐기성, 포자 형성을 하는 병원균으로서 Clostridiaceae과에 속한다. C. perfringens는 인간의 장관과 척추동물 내에서 식중독을 포함하는 질병을 유발한다. 높은 특이성으로 목표 세균을 죽이는 박테리오파지는 병원세균을 제어하는 방법들 중 하나로 여겨져 왔다. 본 연구에서는 C. perfringens를 감염시킬 수 있는 박테리오 파지 CP3의 유전체 염기서열 초안을 보고한다. 본 박테리오파지의 G + C 비율은 34.0%이며, 52,068 bp로 구성된 유전체 DNA를 지니고 있었다. 이 유전체는 74개의 단백질 유전자를 포함하고 있었으며, RNA는 확인되지 않았다.

• 미생물학회지
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• 제54권2호
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• pp.152-154
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• 2018

Klebsiella pneumoniae는 그람 음성균에 속하고 막대 형태를 가지며 인간이나 동물의 폐에 감염하여 병을 일으키는 균이다. K. pneumoniae는 흔히 항생제 내성을 나타내는데 이로 인해 항생제를 통한 치료가 어려워지게 된다. 이런 상황에서 숙주 균에 특이적이고 민감하게 반응하는 박테리오파지는 항생제 내성균의 치료에 대한 대체적인 접근법으로 제안될 수 있다. 박테리오파지 KP1은 하수처리장에서 분리되었으며 K. pneumoniae에 대해 특정적인 감염성이 있다. 본 연구에서는 Klebsiella pneumoniae 박테리오파지 KP1의 유전체 초안 분석을 수행하였다. KP1의 유전체 초안은 167,989 bp의 길이, 39.6%의 G + C 비율로 구성되어있다. 295개의 예측된 ORF들과 14개의 tRNA 유전자를 가지고 있다. 또한 이들은 lysozyme, 그리고 holin과 같은 다양한 세포 용해 관련 효소들을 포함하고 있다.

• Journal of Ginseng Research
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• 제43권1호
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• pp.77-85
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• 2019

Background: Glomus intraradices is a species of arbuscular mycorrhizal fungi that, as an obligate endomycorrhiza, can form mutually beneficial associations with plants. Panax ginseng is a popular traditional Chinese medicine; however, problems associated with ginseng planting, such as pesticide residues, reduce the ginseng quality. Methods: In this experiment, we studied the effect of inoculating G. intraradices on several physiological properties and microbial communities of ginseng. UV-Visible Spectrum method was used to detect physical properties. Denaturing gradient gel electrophoresis method was used to analyze microbial communities. Results: The results indicated that inoculation with G. intraradices can improve the colonization rate of lateral ginseng roots, increase the levels of monomeric and total ginsenosides, and improve root activity as well as polyphenol oxidase and catalase activities. We also studied the bacterial and fungal communities in ginseng rhizospheric soil. In our study, G. intraradices inoculation improved the abundance and Shannon diversity of bacteria, whereas fungi showed a reciprocal effect. Furthermore, we found that G. intraradices inoculation might increase some beneficial bacterial species and decreased pathogenic fungi in rhizospheric soil of ginseng. Conclusion: Our results showed that G. intraradices can benefit ginseng planting which may have some instructive and practical significance for planting ginseng in farmland.

• Mycobiology
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• 제47권2호
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• pp.180-190
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• 2019

In this study, eight-month-old ectomycorrhizae of Tuber borchii with Corylus avellana were synthesized to explore the influence of T. borchii colonization on the soil properties and the microbial communities associated with C. avellana during the early symbiotic stage. The results showed that the bacterial richness and diversity in the ectomycorrhizae were significantly higher than those in the control roots, whereas the fungal diversity was not changed in response to T. borchii colonization. Tuber was the dominant taxon (82.97%) in ectomycorrhizae. Some pathogenic fungi, including Ilyonectria and Podospora, and other competitive mycorrhizal fungi, such as Hymenochaete, had significantly lower abundance in the T. borchii inoculation treatment. It was found that the ectomycorrhizae of C. avellana contained some more abundant bacterial genera (e.g., Rhizobium, Pedomicrobium, Ilumatobacter, Streptomyces, and Geobacillus) and fungal genera (e.g., Trechispora and Humicola) than the control roots. The properties of rhizosphere soils were also changed by T. borchii colonization, like available nitrogen, available phosphorus and exchangeable magnesium, which indicated a feedback effect of mycorrhizal synthesis on soil properties. Overall, this work highlighted the interactions between the symbionts and the microbes present in the host, which shed light on our understanding of the ecological functions of T. borchii and facilitate its commercial cultivation.

• The Plant Pathology Journal
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• 제35권5호
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• pp.445-458
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• 2019

The lipopolysaccharide (LPS) composed of lipid A, core, and O-antigen is the fundamental constituent of the outer membrane in gram-negative bacteria. This study was conducted to investigate the roles of LPS in Burkholderia glumae, the phytopathogen causing bacterial panicle blight and seedling rot in rice. To study the roles of the core oligosaccharide (OS) and the O-antigen region, mutant strains targeting the waaC and the wbiFGHI genes were generated. The LPS profile was greatly affected by disruption of the waaC gene and slight reductions were observed in the O-antigen region following wbiFGHI deletions. The results indicated that disruption in the core OS biosynthesis-related gene, waaC, was associated with increased sensitivity to environmental stress conditions including acidic, osmotic, saline, and detergent stress, and to polymyxin B. Moreover, significant impairment in the swimming and swarming motility and attenuation of bacterial virulence to rice were also observed in the waaC-defective mutant. The motility and virulence of O-antigen mutants defective in any gene of the wbiFGHI operon, were not significantly different from the wild-type except in slight decrease in swimming and swarming motility with wbiH deletion. Altogether, the results of present study indicated that the LPS, particularly the core OS region, is required for tolerance to environmental stress and full virulence in B. glumae. To our knowledge, this is the first functional study of LPS in a plant pathogenic Burkholderia sp. and presents a step forward toward full understanding of B. glumae pathogenesis.

• Fisheries and Aquatic Sciences
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• 제22권2호
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• pp.5.1-5.9
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• 2019

Background: Live fish import may lead to the unintended introduction of pathogens. We examined the monthly distribution of microbial pathogens in ornamental finfish imported into South Korea over a 6-month period. Results: Vibrio alginolyticus was detected in one lemon damsel in June and July; V. vulnificus was detected in one lemon damsel, one caerulean damsel, and one pearl-spot chromis and one ocellaris clownfish in July, April, and May, respectively; Photobacterium damselae was detected in one ocellaris clownfish and one caerulean damsel in June and July, respectively; V. anguillarum was detected in one pearl-spot chromis in February; V. harveyi was detected in one ocellaris clownfish and two mandarin fish in February and April, respectively; Yersinia ruckeri was detected in a pearlscale goldfish group in June and July and in two colored carp groups in July; and Lactococcus garvieae was detected in a lemon damsel group and a sutchi catfish group in July and May, respectively. European catfish virus, the only viral pathogen detected, was found in two sutchi catfish groups in May. Conclusion: This study is the first to identify pathogenic species and the presence or absence of pathogens (non-quarantine diseases) in imported ornamental finfish. These results demonstrate that various pathogens with the potential to harm indigenous fish populations can accompany ornamental finfish imported into South Korea.