• 대한소아치과학회지
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• 제27권1호
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• pp.90-97
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• 2000

치태의 형성은 이온, 효소, 영양물질, 화학물질 등과 같은 구강내 존재하는 다양한 물질들과 이들의 변화에 영향을 받는다. 본 연구에서는 치태형성에 중요한 역할을 하는 구강내 연쇄상구균인 Streptococcus sobrinus를 공시균으로, 비수용성 글루캔의 합성과 세균 증식 에 미치는 여러 인자들의 영향을 관찰하여 다음과 같은 결과를 얻었다. Streptococcus sobrinus 배양 배지의 pH가 7.0일 때 비수용성 글루캔이 가장 많이 합성 되었고, pH 5.5와 pH 8.5에서는 그 합성이 감소하였다. 세균 증식도 pH 7.0에서 가장 활발하였다. 2. 효모 추출물은 2.5%일 때 비수용성 글루캔의 합성과 세균증식이 모두 활발하였다. 자당의 경우 농도가 증가할수록 비수용성 글루캔의 합성은 감소하여 1.25%보다 20%에서 합성이 10배 정도 감소하였으나, 세균의 증식은 20배 정도 증가하였다. 3. 배지의 calcium chloride 농도가 1.0mM, potassium chloride 농도가 40mM, magnesium chloride 농도가 0.1mM 이었을때 비수용성 글루캔의 합성이 가장 활발했으나, 세균의 증식에는 큰 영향을 미치지 않았다. 4. Sodium bicarbonate 10mM에서 비수용성 글루캔 합성과 세균의 증식 이 모두 활발하였으며 100mM 이상에서는 모두 억제되었다. Tris 10mM에서 비수용성 글루캔 합성과 세균의 증식이 모두 억제되었으며 100mM 이상에서는 모두 증가되었다. 5. Sodium phosphate와 potassium phosphate는 10mM 이상에서 비수용성 글루캔 합성과 세균증식이 모두 억제되었다.

• Childhood Kidney Diseases
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• 제20권2호
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• pp.37-44
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• 2016

Although asymptomatic bacteriuria, cystitis, and acute pyelonephritis (APN) have been categorized as urinary tract infections (UTIs), the immunopathogenesis of each disease is different. APN shows an age predilection; the majority of children (over 70-80%) with APN are under 1-2 years of age, with a male predominance. After 1-2 years of age, female predominance has been reported. This finding suggests that the immature immune state of infancy may be associated with the pathogenesis of APN. Escherichia coli is the most common etiologic agent; other uropathogens associated with UTIs originate from the host and comprise normal flora that are continuously altered by environmental factors. Therefore, uropathogens may have characteristics different from those of extraneous bacterial pathogens. Although antibiotic-resistant uropathogens, including extended-spectrum beta-lactamase-producing strains, are increasing in Korea and worldwide, treatment failure is rare in immune-competent children. The immunopathogenesis of APN remains unknown. Intact bacteria may not be the causative substances in renal cell injury; rather, smaller substances produced during bacterial replication may be responsible for renal cell injury and scarring. Moreover, substances from host cells such as proinflammatory cytokines may be involved in renal cell injury. A dimercaptosuccinic acid scan is used to detect the site of bacterial replication in the renal parenchyma, and may be influenced by the size of the focus and the stage of APN. Traditional aggressive studies used to identify vesicoureteral reflux after the first episode of APN have been modified because of rare cases of chronic kidney disease in patients with recurrent UTI.

• Journal of Microbiology and Biotechnology
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• 제9권1호
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• pp.91-97
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• 1999

In this work, a 1.9-kb region of enterococcal plasmid p703/5 was isolated and the nucleotide sequence analysis of the region was performed. One major open reading frame (ORF) was identified encoding a polypeptide of 28 kDa. Database comparisons suggested that the protein showed some homology with other bacterial RepA proteins. Upstream of the ORF, a potential dnaA box, AT-rich region and 22-bp tandemly repeated sequences (DNA iterons), a feature typical for many replication ori sites, were recognized. Deletion analysis using Exonuclease III and several restriction enzymes indicated that the three elements and the gene product from the ORF were essential for replication and that the minimum unit of DNA required for replication resided on the 1.2-kb AvaII subfragment. Thus, this gene product was referred to as RepA.

• 농업생명과학연구
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• 제43권6호
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• pp.77-84
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• 2009

Using recombinant DNA technology, the vector system containing minimal fragment of a bacterial hemoglobin gene (vgb) was constructed. When this vector was inserted into Escherichia coli, the growth of the host was significantly improved in both viable cell counts and absorbance measurement, compared to that of the wild type strain. In addition, by minimizing the size of bacterial hemoglobin in the vector, the ability of vgb in growth improvement was augmented, due to the reduction of metabolic burden from the maintenance and replication of the plasmid. By using this system, it is expected that the growth of microorganisms can be improved even in the hypoxic condition.

• BMB Reports
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• 제38권1호
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• pp.97-103
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• 2005

Under the condition of expression of $\lambda$ P protein at lethal level, the oriC DNA-binding activity is significantly affected in wild-type E. coli but not in the rpl mutant. In purified system, the $\lambda$ P protein inhibits the binding of both oriC DNA and ATP to the wild-type DnaA protein but not to the rpl DnaA protein. We conclude that the $\lambda$ P protein inhibits the binding of oriC DNA and ATP to the wild-type DnaA protein, which causes the inhibition of host DNA synthesis initiation that ultimately leads to bacterial death. A possible beneficial effect of this interaction of $\lambda$ P protein with E. coli DNA initiator protein DnaA for phage DNA replication has been proposed.

• 한국미생물·생명공학회지
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• 제25권6호
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• pp.566-570
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• 1997

During sporulation, Bacillus thuringiensis strains produce crystals consist of toxin proteins highly specific against insect pests. Their host specificities are desirable from a standpoint of environmental safety, but also limit market potential. Thus, development of improved Bacillus thuringiensis strains having broad host spectrum will contribute to increase its use. For the construction of Bacillus thuringiensis strain having broad host spectrum, we cloned cry1C gene encoding a toxin protein highly toxic against Spodoptera exigua from a B. thuringiensis isolate and constructed two recombinant plasmids, pUBClC and plC60. The plasmid PUBC1C has a replication origin of the natural plasmid pBC16 from B. cereus which is closely related species to B. thuringiensis, and the pBC16 was known to be replicated by rolling-circle mechanism. The plasmid pIC60 has a replication origin of a resident 60 MDa plasmid from B. thuringiensis subsp. kurstaki HD263, and it is believed that the pIC60 is replicated in a theta mode. The two plasmids were introduced into B. thuringiensis subsp. kurstaki cryB strain, and the transformed strains produced well-shaped bipyramidal crystals. We confirmed the expression of the cry1C gene by SDS-PAGE, and Western blotting. By investigating the segregational stability, it was found that the plasmid pIC60 is more stable than the pUBC1C.

• The Plant Pathology Journal
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• 제33권6호
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• pp.602-607
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• 2017

Segregation and condensation protein B (ScpB) is essential for replication and segregation in living organisms. Here, we reported the functions of ScpBXv (ScpB-like protein in Xanthomonas campestris pv. vesicatoria) using phenotypic and proteomic analyses. Growth of $Xcv{\Delta}scpBXv$ (ScpBXv knockout mutant) was reduced under both slow and fast growth conditions in rich medium, but comparable to this of the wild-type in plant-mimic conditions. Interestingly, the mutant was significantly less virulent than the wild-type in tomato, indicating that ScpBXv is involved in virulence. To investigate ScpBXv-associated mechanisms, comparative proteomic analyses were carried out and the abundance of 187 proteins was altered. Among them, diverse transcriptional regulators involved in biofilm formation and virulence were abundant in the wild-type. We further showed that biofilm formation of $Xcv{\Delta}scpBXv$ was reduced. This study provides new insights into the functions of ScpBXv in bacterial replication and biofilm formation, which may contribute to the virulence of Xcv.

• 대한수의학회지
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• 제56권2호
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• pp.57-66
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• 2016

The gut epithelial barrier, which is composed of the mucosal layer and the intestinal epithelium, has multiple defense mechanisms and interconnected regulatory mechanisms against enteric microbial pathogens. However, many bacterial pathogens have highly evolved infectious stratagems that manipulate mucin production, epithelial cell-cell junctions, cell death, and cell turnover to promote their replication and pathogenicity in the gut epithelial barrier. In this review, we focus on current knowledge about how bacterial pathogens regulate mucin levels to circumvent the epithelial mucus barrier and target cell-cell junctions to invade deeper tissues and increase their colonization. We also describe how bacterial pathogens manipulate various modes of epithelial cell death to facilitate bacterial dissemination and virulence effects. Finally, we discuss recent investigating how bacterial pathogens regulate epithelial cell turnover and intestinal stem cell populations to modulate intestinal epithelium homeostasis.

• 한국작물학회:학술대회논문집
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• 한국작물학회 2017년도 9th Asian Crop Science Association conference
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• pp.245-245
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• 2017

Heavy metal pollution of agricultural soils affects land productivity and has impact on the quality of surrounding ecosystem. Soil microbial community parameters are used as reliable indices for assessing quality of agricultural lands under metal stress. This study investigated bacterial community structure of polluted and undisturbed paddy soils to elucidate soil factors that are related to alteration of bacterial communities under conditions of metal pollution. No obvious differences in the richness or diversity of bacterial communities were observed between samples from polluted and control areas. The bacterial communities of three locations were distinct from one another, and each location possessed distinctive set of bacterial phylotypes. The abundances of several phyla and genera differed significantly between study locations. Variation of bacterial community was mostly related to soil general properties at phylum level while at finer taxonomic levels concentrations of arsenic and lead were significant factors. According to results of bacterial community functional prediction, the soil bacterial communities of metal polluted locations were characterized by more abundant DNA replication and repair, translation, transcription and nucleotide metabolism pathway enzymes while amino acid and lipid metabolism as well as xenobiotic biodegradation potential was reduced.Our results suggest that the soil microbial communities had adapted to the elevated metal concentrations in the polluted soils as evidenced by changes in relative abundances of particular groups of microorganisms at different taxonomic resolution levels, and by altered functional potential of the microbial communities.

• Journal of Animal Science and Technology
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• 제59권2호
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• pp.4.1-4.5
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• 2017

Background: Biofilms were the third-dimensional structure in the solid surface of bacteria. Bacterial biofilms were difficult to control by host defenses and antibiotic therapies. Escherichia coli (E. coli) and Salmonella were popular pathogenic bacteria that live in human and animal intestines. Essential oils are aromatic oily liquids from plant materials and well known for their antibacterial activities. Method: This study was conducted to determine effect of essential oil on anti-biological biofilm formation of E. coli and Salmonella strains in in vitro experiment. Two kinds of bacterial strains were separated from 0.2 g pig feces. Bacterial strains were distributed in 24 plates per treatment and each plates as a replication. The sample was coated with a Bacterial biofilm formation was. Result: Photographic result, Escherichia coli (E. coli) and Salmonella bacteria colony surface were thick smooth surface in control. However, colony surface in blended and single essential oil treatment has shown crack surface layer compared with colony surfaces in control. Conclusion: In conclusion, this study could confirm that essential oils have some interesting effect on anti-biofilm formation of E. coli and Salmonella strains from pig feces.