• Korean Journal of Microbiology
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• v.54 no.3
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• pp.244-253
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• 2018

This study was carried out to evaluate effects of antimicrobial substances produced by isolated soil bacteria. Among two thousands of bacterial isolates Paenibacillus elgii DS381 exhibited high antimicrobial activities against several microbial residents on human skin and pathogenic bacteria. DS381 showed 15.3~26.0 mm inhibition zone diameter against all target bacteria and yeast in agar well diffusion test. Antimicrobial peptide produced by DS381 indicated low minimum inhibitory concentration (0.039-5.000 mg/ml). DS381 produced biosurfactant such as lipopeptide, and surface tension of culture supernatant of DS381 reduced from 60.0 to 40.3 mN/m. DS381 also showed $1.56{\pm}0.13U/ml$ of chitinase activity. These results suggest that Paenibacillus elgii DS381 may be utilized as an efficient biocontrol agent against some important human skin microbes and pathogenic bacteria.

• Korean journal of applied entomology
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• v.49 no.3
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• pp.241-249
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• 2010

Two groups of entomopathogenic bacteria, Xenorhabdus and Photorhabdus, are known to suppress insect immune responses by inhibiting eicosanoid biosynthesis. This study used these bacterial culture broths to develop novel biochemical insecticides against the diamondback moth, Plutella xylostella. Though the bacterial culture broths alone showed little insecticidal activity, they significantly enhanced pathogenicity of Bacillus thuringiensis against the fourth instar larvae of P. xylostella. Sterilization of the bacterial culture broth by autoclaving or $0.2\;{\mu}m$ membrane filtering did not influence the synergistic effect on the pathogenicity of B. thuringiensis. Three metablites identified in the culture broth of X. nematophila also showed similar synergistic effects. In field test, both entomopathogenic bacterial culture broth also enhanced the control efficacy of B. thuringiensis against P. xylostella.

• YAKHAK HOEJI
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• v.22 no.2
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• pp.59-71
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• 1978

사람에게 병을 일으키는 수 많은 세균이 분비하는 다수의 외독소중, 이곳에서는 Corynebacterium diphtheriae의 외독소인 디프테리아 독소와 Vibrio cholerae가 분비하는 콜레라 장내 독소에 관해 주로 논하기로 하며, 디프테리아 독소와 생화학적 병인성 기전이 비슷한 Pseudomonas aeruginosa가 분비하는 pseudomnas외독소와 콜레라 장내독소와 병인성기전이 유사한 Escherichia coli의 장내독소에 관하여는 간략하게 언급하고져 한다.

• Korean journal of applied entomology
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• v.32 no.3
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• pp.330-337
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• 1993

A bacterium, pathogenic to Nilaparvata lugens Stal. causing high mortality in 3~5 days, were selected and identified as Serratuz marcescens biotype A2a which is not a nosocomlally infective strain. In order to determine the characters of Serratia marcesce'1lS associated with insect pathogenicity, Tn5 mutagenesis was carried out by conjugating with E. coli pJB4J1. Transconjugants were plate-assayed for missing chitinase, protease and DNase activity. A protease negative mutant was selected for missing JOseet pathogenicity. SEM and TEM revealed the presence of bacterial cells in the epithelial tissue of inner abdomal tissue of the hypodermic layer of abdomen. Such a colonization was limmited to the subjacent tissue inside the intacL cuticular epidermis. These observation supported our result of pathogenicity tests of transconjugants.

• The Korean Journal of Malacology
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• v.14 no.1
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• pp.19-26
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• 1998

북만 해수의 물리 화학적 및 미생물학적 특성과 북만에서 양식되고 있는 굴에 대한 세균학적 수질을 조사하여 수출용 패류생산지정 해역수질에 합당한가를 파악함과 동시에 지표세균의 조성, 병원성 세균 등을 조사한 결과를 요약하면 다음과 같다.사 기간중 불반 해수의 수온은 6.8 -23.$0^{\circ}C$, 투명도는 2.7-5.9m, COD 1.55-2.12 mg/1, DO 6.3-10.1 mg/1, 용존질소 1.63-20.87 $\mu\textrm{g}$-at/1, 인산염 0.16-1.66 $\mu\textrm{g}$-at/1, Chlorophyll. a는 1.04-6.78 mg/ ㎥범위였으며 염분농도는 31.57-34.47$\textperthousand$였다. 북만 해수의 세균학적 수질은 통영항, 인평포, 법송포 및 북신만 안쪽의 일부 해역을 제외하고는 수출용 패류의 생산해역의 수질기준에 합당하였다. 대장균군의 최확수는 양식을 하지 않는 조사지점 1과 2를 제외하고 해수 100ml 당 < 3.0-4,600의 범위였으며 230을 초과하는 시료의 비율은 10.7%였고, 분변계 대장균의 최확수는 <3.0-1,100의 범위였으며 43을 초과하는 시료의 비율은 9.5%로 한계치 10%를 약간 상회하였다. 대장균군의 분류겨로가 Escherichia coli가 약 52%나 되어 오염원의 주류가 분변오염임을 알 수 있었다. 살모넬라, 시겔라, 콜레라균 등 수인성 병원세균은 검출되지 않았다. 병원성 비브리오균은 여름철인 6-8월 사이에는 시료의 9-22%에서 양성으로 나타났다. 굴 내에 생균수는 2.0 x $10^{2}$-1.6 x $10^{3}$범위였고 대장균군의 최확수는 <18 - 16,000, 중앙치는 176, 분변계 대장균은 <18-2,400, 중앙치는 었다.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.35 no.2
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• pp.132-136
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• 1990

This experiment was conducted to study the multiplication and spread of bacterial population in water exuded through the hydathode of infected leaf of Xanthomonas campestris pv. oryzae in resistant and susceptible rice cultivars to bacterial leaf blight. The results obtained are summarized as follows. The bacterial multiplication in resistant cultivars was almost constant from three days to twelve days after inoculation with population of 10$^3$-10$^4$cfu/$\textrm{cm}^2$, but the multiplication was increased as days after inoculation extended in susceptible cultivars. The speed of bacterial multiplication and the number of bacteria spread above and below the inoculated position were closely related with the resistance of rice cultivars to bacterial leaf blight. The bacterial multiplication and spread were observed throughout the all growing stages including seedling, maximum tillering and flag leaf stages. The bacterial populations in water exuded through the hydathode were dependent on the multiplication and spread, and the populations were also closely related with the resistance of rice cultivars.

• Journal of Life Science
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• v.31 no.1
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• pp.100-108
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• 2021

In the oral cavity, there are hundreds of microbial species that exist as planktonic cells or are incorporated into biofilms. The accumulation and proliferation of pathogenic bacteria in the oral biofilm can lead to caries and periodontitis, which are typical oral diseases. The oral bacteria in the biofilm not only can resist environmental stress inside the oral cavity, but also have a 1,000 times higher resistance to antibiotics than planktonic cells by genes exchange through the interaction between cells in the oral biofilm. Therefore, if the formation of oral biofilm is suppressed or removed, oral diseases caused by bacterial infection can be more effectively prevented or treated. In particular, since oral biofilms have the characteristic of forming a biofilm by gathering several bacteria, quorum sensing, a signaling system between cells, can be a target for controlling the oral biofilm. In addition, a method of inhibiting biofilm formation by using arginine, an alkali-producing substrate of oral bacteria, is used to convert the distribution of oral microorganisms into an environment similar to that of healthy teeth or inhibit the secretion of glucosyltransferase by S. mutans to inhibit the formation of non-soluble glucans. It can be a target to control oral biofilm. This method of inhibiting or removing the oral biofilm formation rather than inducing the death of pathogenic bacteria in the oral cavity will be a new strategy that can selectively prevent or therapeutic avenues for oral diseases including dental caries.

• Proceedings of the Korean Society for Food Science of Animal Resources Conference
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• 2005.05a
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• pp.203-206
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• 2005

시중의 정육점 및 백화점 등에서 유통 중인 10종의 우육 원료에 대한 일반 세균수, 저온균수, 고온균, 혐기성균 및 진균류, 대장균군에 대한 미생물학적 분포와 병원성 미생물에 대한분리${\cdot}$동정을 실시하였다. 실험결과 원료 우육에서 중온균은 $3.8{\times}\;10^3{\sim}1.4{\times}\;10^5\;cfu/g$으로 높은 분포를 보였다. 저온균은 $9.2{\times}\;10^3{\sim}1.0{\times}\;10^5\;cfu/g$으로 지표세균 중에서 가장 높은 분포를 나타내었고, 혐기성균은 중온균, 저온균과 유사한 분포를 보였으나 상대적으로 적게 검출되었고, 고온균은 모든 검체에서 검출되지 않았다. 대장균군 또한 모든 시료에 대해서 검출되지 않았다. 효모와 곰팡이류는 $2.2{\times}\;10^1{\sim}7.8{\times}\;10^2\;cfu/g$으로 검출되었다. 병원성 미생물은 우육 sample B, G, H에서 B. cereus 만이 검출되었고, 동정결과 99.8%의 상동성을 보였다.

• Proceedings of the Korean Society of Soil Zoology Conference
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• 1998.10a
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• pp.15-15
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• 1998

• The Korean Journal of Food And Nutrition
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• v.22 no.3
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• pp.396-401
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• 2009

Microorganisms or their toxins can be transferred to eggs and cause food poisoning in humans. Therefore, this study was conducted to detect microbial contamination of eggs and to identify microorganisms in any contaminated eggs. Four different brands of eggs were collected from hypermarkets in the northern Gyeonggi area. The total bacterial counts on the shells of the eggs varied greatly between brands. In addition, various bacterial species including Klebsiella pneumoniae, Pseudomonas mendocina, Alcaligenes xylosoxidans, Alcaligenes faecalis, and Enterobacter cloacae were identified on eggshells. Furthermore, mean of total bacterial counts of four brands was $3.4{\times}10^4 cfu/m{\ell}$ and E. coli was detected on the eggshell of one brand egg. However, Salmonella was not identified on all brands of collected eggs. We also demonstrated that the E. coli isolated from the eggshell was not pathogenic based on the absence of pathogen-specific gene expression patterns. Taken together, the result of this study indicate that strict quality control and improved distribution controls are required to decrease microbial contamination and improve human health.