• Journal of Life Science
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• v.23 no.5
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• pp.676-681
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• 2013

Perchlorate (${ClO_4}^-$) is an emerging contaminant found in surface water and soil/groundwater. Microbial removal of perchlorate is the method of choice since perchlorate-reducing bacteria (PRB) can reduce perchlorate to harmless end-products. A previous study [3] showed experimental evidence of autotrophic perchlorate removal using elemental sulfur granules and activated sludge. The granular sulfur is a relatively inexpensive electron donor, and activated sludge is easily available from a wastewater treatment plant. A batch test was performed in this study to further investigate the effect of various environmental parameters on the perchlorate degradation by sludge microorganisms when elemental sulfur was used as electron donor. Results of the batch test suggest optimum conditions for autotrophic perchlorate degradation by sludge microorganisms. The results also show that sulfur-oxidizing PRB enriched from activated sludge removed perchlorate better than activated sludge. Taken together, this study suggests that autotrophic perchlorate removal using elemental sulfur and activated sludge can be improved by employing optimized environmental conditions and enrichment culture.

• Journal of dental hygiene science
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• v.13 no.4
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• pp.403-409
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• 2013

The purpose of this study was to evaluate the correlation between caries experience, Quantitative Light-Induced Fluorescence-Digital (QLF-D) redings and new caries activity test (Cariview) results in preschool children. Fifty-seven healthy kindergarten children (male 28, female 29) were participated this study. The calibrated dentist investigated the caries experience of children and new caries activity test. Cariview samples were incubated in the activated medium at $37^{\circ}C$ for 48 hours. All QLF-D taking and readings were performed by one experienced and trained operator under identical conditions in a dental unit chair located in a darkened room. Analysis range was limited to the maxillary and mandibular anterior teeth. QLF-D redings (white spot and dental plaque) were analysed using QLF system. The dft index had a relatively high correlation with the QLF-D redings (white spot: r=0.617, simple plaque score: r=0.500) (p<0.01). Also, there was significant correlation between dft index and the Cariview score (r=0.286) (p<0.05). However, the Cariview score had no significant correlation between dt index and ft index (p>0.05). QLF-D can be evaluated objectively the initial caries lesions and dental plaque correlated with caries experience. Therefore, QLF-D will be useful to the study of caries prediction.

• The Korean Journal of Mycology
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• v.46 no.3
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• pp.333-344
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• 2018

Selection of the optimal culture medium and evaluation of the antimicrobial activity against various phytopathogens were performed for four entomopathogenic fungal isolates with excellent insecticidal and antimicrobial activity against the two-spotted spider mite (Tetranychus urticae), green peach aphid (Myzus persicae), and gray mold (Botrytis cinerea). The optimal medium was selected by measuring the amount of blastospore production and the antifungal activity of the culture medium. On the basis of these experiments, GY medium was selected for Beauveria bassiana 2R-3-3-1 and Metarhizium anisopliae 4-2, SD3, and PDB medium for B. bassiana SD15. The antimicrobial activity test against other phytopathogens indicated that all four isolates showed high antifungal activities against Colletotrichum acutatum and Sclerotinia sclerotiorum. However, for Phytophthora capsici and C. fructicola, only M. anisopliae SD3 showed a high antifungal activity against P. capsici, and the other three isolates had little activity. Antibacterial activity against Clavibacter michiganensis subsp. michiganensis was high in two isolates of M. anisopliae but not in two isolates of B. bassiana. Thus, it was confirmed that entomopathogenic fungi effective for pest control could be effectively used as a control agent for various plant diseases.

• Journal of Life Science
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• v.21 no.3
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• pp.473-479
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• 2011

Adenylyl cyclase (AC) catalyzes the formation of cyclic AMP (cAMP) from ATP. The cAMP produced by AC serves as a secondary messenger in a variety of signal transduction pathways, and controls various cellular functions in many organisms. ACs can be grouped into six classes based on their primary amino acid sequences. Eukaryotes and mycobacteria contain only members of class III AC. The catalytic cyclase domains of class III AC are active as dimers: mammalian ACs, which are composed of a single polypeptide with two catalytic cyclase domains, form the active site as a result of intramolecular dimerization of the catalytic cyclase domains. In contrast, mycobacterial ACs function as homodimers, since their polypeptides contain a single catalytic cyclase domain. Six amino acids are required for the catalytic activity of class III AC - two aspartate residues, a lysine-aspartate pair and an arginine-asparagine pair. 16 ACs belonging to the class III were identified in Mycobacterium tuberculosis H37Rv, and their characteristics are reviewed.

• Korean Journal of Microbiology
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• v.39 no.3
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• pp.141-147
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• 2003

The simultaneous expression levels of antifungal activity related genes was analyzed by DNA microarray. We constructed DNA chips contained 2,000 randomly digested genome spots of the antifungal bacterium of Bacillus lentimorbus WJ5 and compared its quantitative aspect with 7 antifungal activity deficient mutants induced by gamma radiation ($^{60}Co$). From the analysis of microarray hybridization by the Gene Cluster (Michael Eisen, Stanford Univ.), totally 408 genes were expressed and 20 genes among them were significantly suppressed in mutants. pbuX (xanthine permease, K222), ywbA (phosphotransferase system enzyme II, K393), ptsG (PTS glucose specific enzyme II ABC component, K877), yufO (ABC transporter (ATP-binding protein), K130l), and ftsY (signal recognition particle (docking protein), K868) were simultaneously down-regulated in all mutants. It suggested that they were supposed to be related to the antifungal activity of B. lentimorbus WJ5.

• Journal of Dental Rehabilitation and Applied Science
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• v.37 no.4
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• pp.244-250
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• 2021

Purpose: The purpose of this study was to examine effects of culture conditions on the growth and antibacterial activity of Streptococcus salivarius K12. Materials and Methods: S. salivarius K12 was cultivated in medium containing animal and plant protein or in medium of neutral and acidic conditions. The growth of S. salivarius K12 was measured every 2 hours by a spectrophotometer. The antimicrobial activity of S. salivarius K12 against Streptococcus mutans and Porphyromonas gingivalis was investigated by the susceptibility assay using the spent culture medium. Results: the growth of S. salivarius K12 showed faster in medium containing plant protein and neutral pH condition. The antimicrobial and antifungal activity of S. salivarius K12 appeared stronger in medium containing plant protein than animal proteins. Conclusion: For application of S. salivarius K12 to bacterial oral disease, co-substances may be needed for S. salivarius K12 to colonize in the oral cavity and enhance the antimicrobial activity.

• KSBB Journal
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• v.21 no.1 s.96
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• pp.72-78
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• 2006

This study was carried out to investigate the antimicrobial and antioxidative effects of mycelium cultural extract from mushroom. Mushroom mycelium was grown in a defined synthetic liquid medium and citrus extracts, and the culture extracts were examined for antioxidant and antibacterial activity. Myceliums of Phellinus linteus, Cordyceps militaris, Coriolus versicolor, Sparassic crispa, Agaricus blazei, lnonotus obliquus, Lentinus edodes, Hericium erinacium, Gonoderma lucidium in 10% citrus extract supplemented medium and synthesis medium were incubated in a shaking incubator (120 rpm, $24{\sim}30^{\circ}C$ ) for $7{\sim}15$ days. The antimicrobial activity of the culture fluid of mushroom mycelium grown in submerged liquid culture was tested against 12 microorganisms which were fish pathogens and common bacterial species. The culture extracts showed high activity against Vibrio sp. and had poor effect on Streptocouus sp., S. parauberis, S. iniae. The culture extracts obtained from the synthetic medium showed $30{\sim}93%$ of the 1,1-diphenyl-2-picrylhydrazyl radical scavenger activity, the culture extracts obtained from the citrus extracts medium exhibited antioxidant activity up to 55%.

• Journal of Periodontal and Implant Science
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• v.37 no.sup2
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• pp.297-310
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• 2007

치조골 흡수는 파골세포와 matrix metalloproteinases (MMPs)에 의한 골의 무기질과 유기질의 파괴로 일어나는 과정이다. 세균성 산물, 주로 내독소는 치은조직 내에서 염증세포의 유주, 사이토카인 생산, 조직파괴 효소 분비 및 파골세포 활성 등의 국소 면역반응을 유도한다. A. actinomycetemcomitans는 급진성 치주염의 원인 균주중 하나로 그 내독소는 치조골의 흡수와 관련된다. MMP-13은 세균성 산물이나 염증성 사이토카인의 자극에 의해 분비되며, 최근의 연구 결과들은 MMP-13이 치주질환의 진행과 골 흡수 과정에서 일정한 역할을 담당하는 것으로 보고하고 있으나, A. actinomycetemcomitans 내독소와 MMP-13과의 관련성에 대한 연구는 미미하다. 이에 이번 연구에서는 A. actinomycetemcomitans 내독소에 의한 MMP-13의 발현과 파골세포 형성을 세포배양을 통하여 관찰하였고, 백서 구개부 치은에 A. actinomycetemcomitans 내독소를 주입하여 흡수가 진행되고 있는 치조골에서 파골세포의 분화와 MMP-13의 발현을 TRAP 염색, 면역조직화학적 방법 등을 통해 관찰하여 다음과 같은 결과를 얻었다. MMP-13 mPNA의 발현은 A. actinomycetemcomitans 내독소 (1ug/ml)로 24시간 자극한 마우스 치주인대 섬유모세포에서 생리식염수로 자극한 세포에 비하여 약 2.6배 증가하였으며 마우스 대식세포에서는 TRAP 양성 세포가 대조군보다 더 많이 나타났다. A. actinomycetemcomitans 내독소를 주입한 백서 치주조직에서는 대조군보다 더 심한 골소실을 보였다. TRAP-양성 다핵 파골세포 유사세포는 치주염군과 대조군 모두 치조골에서 관찰되었다. TRAP-양성 다핵 파골세포 유사세포는 치주염군에서 대조군보다 유의하게 많은 숫자가 관찰되었으며, 치주염군에서 대조군보다 유의하게 많은 숫자가 관찰되었다. MMP-13 면역양성 반응은 치주염군에서 거친 골연을 갖는 치조골상에 배열된 조골세포와 그 인접한 치주인대에서 관찰되었으며 대조군에서는 MMP-13 면역 양성 반응이 치조골 표면에서만 일부 관찰되었다. 이상의 결과는 A. actinomycetemcomitans 내독속가 MMP-13의 발현을 증가시키며 파골세포의 활성을 통하여 치조골의 흡수를 유도함을 시사한다. 또한 A. actinomycetemcomitans 내독소 투여에 의한 실험적 모델은 백서에서 중등도의 골 소실을 동반한 만성 치주염 모델로 향후 치주질환 치료제의 효과를 평가하는데 유용하게 사용될 수 있으리라 기대된다.

• Korean Journal of Microbiology
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• v.51 no.2
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• pp.177-180
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• 2015

For prevention of atrophic rhinitis of swine by Bordetella bronchiseptica and fowl typhoid by Salmonella gallinarum, bacterial strains showing antimicrobial activity against those pathogenic bacteria were isolated from various samples collected at animal farms. Among 372 bacterial isolates strain TK3 showed the highest antibacterial activity against both pathogens, and was identified as Bacillus amyloliquefaciens by 16S rRNA gene sequence analysis. B. amyloliquefaciens TK3 could inhibit growth of both pathogens by secretion of antibacterial compounds such as siderophore, rhamnolipid and antimicrobial peptide. Production radius of siderophore on Chrome azurol S agar plate by strain TK3 was 0.53 cm after 14 days of incubation, and concentration of siderophore in King's B medium was 1.06 mmol/ml. It also secreted 82.4 mg/L of rhamnolipid, and antimicrobial peptide that completely inhibited growth of both pathogens at concentration of $30{\mu}l/ml$ in LB medium.

• Polymer(Korea)
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• v.35 no.5
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• pp.419-423
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• 2011

Chitosan is a natural polymer derived from chitin that has been widely used as a dietary supplement and in a variety of pharmacological and biomedical applications. In addition, water-soluble chitosan has been used to enhance the stability of chitosan in water and reduce cytotoxic activity induced by acetic acid. In this study, the antibiotic activity and mechanism of low molecular weight water-soluble chitosan (LMWSC; MW1, MW3, MW5, and MW10) were examined in pathogenic bacteria cells and vesicles containing bacterial membrane lipids. MW10 displayed potent antibacterial activity against pathogenic bacteria strains and no cytotoxicity against mammalian cells. In addition, the degree of calcein leakage was examined as a function of lipid composition (PE/PG=7/3 w/w). The results of these experiments demonstrated that MW10 promoted leakage in negatively-charged membranes. Furthermore, confocal microscopy revealed that MW10 was located in the plasma membrane.