• 동의생리병리학회지
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• 제21권5호
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• pp.1148-1153
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• 2007

Streptococcus mutans is considered one of the primary etiologic agents of dental caries. we studied the effect of the ethanol extracts of Tribuli fructus (T. fructus) on the growth, biofilm formation, acid production, adhesion and insoluble glucan synthesis of S. mutans. The ethanol extracts of T. fructus showed concentration dependent inhibitory activity against the growth and acid production of S. mutans, and produced significant inhibition at the concentration of 0.025, 0.05, 0.1, 0.2, 0.3, 0.5 mg/ml compared to the control group. In the biofilm assay, the ethanol extracts of T. fructus inhibited formation of biofilm synthesized by S. mutans at the concentration of 0.05 mg/ml. The extracts markedly inhibited S. mutans adherence to HA treated with saliva, and cell adherence was repressed by more than 50% at the concentration 0.05 mg/ml. On the activity of glucosyltransferase which synthesizes water insoluble glucan form sucrose, ethanol extract of T. fructus showed more than 10% inhibition over the concentration of 0.025 mg/ml. Hence, we conclude that T. fructus might be a candidate of anticaries agent. Further studies are necessary to clarify the active constituents of T. fructus responsible for such biomolecular activities.

• 한국환경과학회지
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• 제23권6호
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• pp.1101-1109
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• 2014

In this study we followed biofilm formation and development in a granular activated carbon (GAC) filter on pilot-scale during the 12 months of operation. GAC particles and water samples were sampled from four different depths (-5, -25, -50 and -90 cm from surface of GAC bed) and attached biomass were measured with adenosine tri-phosphate (ATP) analysis and heterotrophic plate count (HPC) method. The attached biomass accumulated rapidly on the GAC particles of top layer throughout all levels in the filter during the 160 days (BV 23,000) of operation and maintained a steady-state afterward. During steady-state, biomass (ATP and HPC) concentrations of top layer in the BAC filer were $2.1{\mu}g{\cdot}ATP/g{\cdot}GAC$ and $3.3{\times}10^8cells/g{\cdot}GAC$, and 85%, 83% and 99% of the influent total biodegradable dissolved organic carbon ($BDOC_{total}$), $BDOC_{slow}$ and $BDOC_{rapid}$ were removed, respectively. During steady-state process, biomass (ATP and HPC) concentrations of middle layer (-50 cm) and bottom layer (-90 cm) in the BAC filter were increased consistently. Biofilm development (growth rate) proceed highest rate in the top layer of filter (${\mu}_{ATP}=0.73day^{-1}$; ${\mu}_{HPC}=1,74day^{-1}$) and 78%~87% slower in the bottom layer (${\mu}_{ATP}=0.14day^{-1}$; ${\mu}_{HPC}=0.34day^{-1}$). This study shows that the combination of different analytical methods allows detailed quantification of the microbiological activity in drinking water biofilter.

• Journal of Microbiology and Biotechnology
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• 제15권5호
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• pp.952-964
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• 2005

The diesel-degrading activities of biofilms sampled from petroleum-contaminated groundwaters in urban subway drainage systems were examined in liquid cultures, and the microbial populations of the biofilms were characterized by denaturing gel gradient electrophoresis (DGGE) and 16S rDNA sequence analysis. Biofilm samples derived from two sites (19 K and 20 K) at subway Station N and Station I could degrade around $80\%$ of applied diesel within 20 and 40 days, respectively, at $15^{\circ}C$, and these results were strongly correlated with the growth patterns of the biofilms. The closest phylogenetic neighbor of a dominant component in the 19 K biofilm was Thiothrix fructosivorans strain Q ($100\%$ similarity). Four dominant strains in the 20 K biofilm were closely related to Thiothrix fructosivorans strain Q ($100\%$ similarity), Thiothrix sp. CC-5 ($100\%$ similarity), Sphaerotilus sp. IF14 ($99\%$ similarity), and Cytophaga-Flexibacter-Bacterioides (CFB) group bacterium RW262 ($98\%$ similarity). Three dominant members in the Station I biofilms were very similar to uncultured Cytophagales clone CRE-PA82 ($91\%$ similarity), Pseudomonas sp. WDL5 ($97\%$ similarity), and uncultured CFB group bacterium LCK-64 ($94\%$ similarity). The microbial components of the biofilms differed depending on the sampling site. This is the first report on the isolation of clones highly similar to Thiothrix fructosivorans and Thiothrix sp. from biofilms in petroleum-polluted groundwaters, and the first evidence that these organisms may play major roles in petroleum degradation and/or biofilm-development.

• 대한토목학회논문집
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• 제7권3호
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• pp.45-53
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• 1987

본(本) 연구(硏究)의 목적(目的)은 충전상(充塡床) 호기성(好氣性) 생물막공법(生物膜工法)의 반응속도론(反應速度論)을 구명(究明)하는 것으로서, 폭기(曝氣)되는 충전상(充塡床) 반응조(反應槽)에 합성폐수(合成廢水)를 주입(注入)함으로써 실험(實驗)이 수행(遂行)되었다. 유리구슬을 매질(媒質)로 채운 반응조(反應槽)의 공칭체류시간(公稱滯留時間)은 5시간(時間)이었으며, 반응조내(反應槽內)에서의 흐름형태는 소금용액을 사용한 추적자(追跡子) 실험(實驗) 결과(結果) 완전혼합형(完全混合形)이었음이 알려졌다. 연구결과(硏究結果)에 따르면 유기물(有機物) 용적부하(容積負荷)가 증가함에 따라 미생물막(微生物膜)의 성장(成長)에 의하여 반응구내(反應構內)에서의 미생물량(微生物量)이 증가함으로 F/M는 거의 일정(一定)한 값으로 유지(維持)되었다. 또한 충전상(充塡床) 호기성(好氣性) 생물막공법(生物膜工法)이 슬러지반송(返送)이 있는 완전혼합(完全混合) 활성(活性)슬러지 공법(工法)의 반응속도론(反應速度論)에 의하여 해석될 수 있음이 구명(究明)되었다.

• The Plant Pathology Journal
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• 제29권1호
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• pp.59-66
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• 2013

Colonization studies previously performed with a green-fluorescent-protein, GFP, labeled derivative of Bacillus amyloliquefaciens FZB42 revealed that the bacterium behaved different in colonizing surfaces of plant roots of different species (Fan et al., 2012). In order to extend these studies and to elucidate which genes are crucial for root colonization, we applied targeted mutant strains to Arabidopsis seedlings. The fates of root colonization in mutant strains impaired in synthesis of alternative sigma factors, non-ribosomal synthesis of lipopeptides and polyketides, biofilm formation, swarming motility, and plant growth promoting activity were analyzed by confocal laser scanning microscopy. Whilst the wild-type strain heavily colonized surfaces of root tips and lateral roots, the mutant strains were impaired in their ability to colonize root tips and most of them were unable to colonize lateral roots. Ability to colonize plant roots is not only dependent on the ability to form biofilms or swarming motility. Six mutants, deficient in abrB-, sigH-, sigD-, nrfA-, yusV and RBAM017410, but not affected in biofilm formation, displayed significantly reduced root colonization. The nrfA- and yusV-mutant strains colonized border cells and, partly, root surfaces but did not colonize root tips or lateral roots.

• 환경생물
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• 제36권2호
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• pp.190-198
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• 2018

The petroleum industry is an important part of the world economy. However, the massive exposure of petroleum in nature is a major cause of environmental pollution. Therefore, the microbial mediated biodegradation of petroleum residues is an emerging scientific approach used to resolve these problem. Through the screening of diesel contaminated soil we isolated a rapid phenanthrene and a diesel degrading bacterium identified as Enterobacter cancerogenus DA1 strain through 16S rRNA gene sequence analysis. The strain was registered in NCBI with an accession number MG270576. The optimal growth condition of the DA1 strain was determined at pH 8 and $35^{\circ}C$, and the highest degradation rate of the diesel was achieved at this condition. At the optimal condition, growth of the strain on the medium containing 0.05% phenanthrene and 0.1% of diesel-fuel was highest at 45 h and 60 h respectively after the incubation period. Biofilm formation was found significantly higher at $35^{\circ}C$ as compared to $30^{\circ}C$ and $40^{\circ}C$. Likewise, the lipase activity was found significantly higher at 48 h after the incubation compared to 24 h and 72 h. These results suggest that the Enterobacter cancerogenus DA1 could be an efficient candidate, for application through ecofriendly scientific approach, for the biodegradation of petroleum products like diesel.

• Journal of Microbiology and Biotechnology
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• 제29권8호
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• pp.1221-1229
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• 2019

Mycobacterium tuberculosis, a causative pathogen of tuberculosis (TB), still threatens human health worldwide. To find a novel drug to eradicate this pathogen, we tested taurine-5-bromosalicylaldehyde Schiff base (TBSSB) as an innovative anti-mycobacterial drug using Mycobacterium smegmatis as a surrogate model for M. tuberculosis. We investigated the antimicrobial activity of TBSSB against M. smegmatis by plotting growth curves, examined the effect of TBSSB on biofilm formation, observed morphological changes by scanning electron microscopy and transmission electron microscopy, and detected differentially expressed proteins using two-dimensional gel electrophoresis coupled with mass spectrometry. TBSSB inhibited mycobacterial growth and biofilm formation, altered cell ultrastructure and intracellular content, and inhibited cell division. Furthermore, M. smegmatis adapted itself to TBSSB inhibition by regulating the metabolic pathways and enzymatic activities of the identified proteins. NDMA-dependent methanol dehydrogenase, NAD(P)H nitroreductase, and amidohydrolase AmiB1 appear to be pivotal factors to regulate the M. smegmatis survival under TBSSB. Our dataset reinforced the idea that Schiff base-taurine compounds have the potential to be developed as novel anti-mycobacterial drugs.

• 상하수도학회지
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• 제10권1호
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• pp.78-84
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• 1996

The presence of ammonia, usually in the form of ammonium ion ($NH_4{^+}$), can enhance bacterial growth m the distribution system and make the production of drinking water more costly if ammonium must be removed to ensure good disinfection. Removal of ammonia by biological oxidation could be economical which prevents excess chlorine dosage In this research, effects of hydraulic retention time (HRT) and media type on the ammonia removal efficiencies of submerged biofilm reactor were investigated. The biofilm reactors combined the characteristics of high biological solids capture efficiency and good hydraulic control. The results indicate that biofilms can remove over 77 percent of the ammonia with HRT of longer than 2 hr even at low temperature ranging from 14.6 to $16.6^{\circ}C$. The HRT has a significant effect on nitrification. The overall nitrification and efficiency of ammonia removal increase with increasing HRT. It has also been observed that when the fibrous media was used, the ammonia removal, nitrification rate and endurance to shock improved.

• 한국환경과학회지
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• 제11권3호
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• pp.209-214
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• 2002

The lab-scale anaerobic continuous reactor which was filled with the sludge of anaerobic digestion from Suyoung wastewater treatment plant was operated by feeding of various concentrations and flow rates. This experiment indicated that more than 6,870 mgCOD/L of substrate concentration was required to promote good metabolism and growth of anaerobic biomass. And increasing loading rate slowly was also required in order to treat substrate of higher concentration and higher loading rate. The substrate concentration of about 10,000 mgCOD/L was adequate to generate biogas efficiently. The pH was sharply decreased at the onset of higher leading rate, but the pH was restabilized soon at 8. During the experiment, the amount of the attached biomass was kept constant.

• Archives of Plastic Surgery
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• 제49권2호
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• pp.141-149
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• 2022

Breast implant-associated anaplastic large cell lymphoma (BIA-ALCL) is a recently spotlighted T-cell origin non-Hodgkin's lymphoma with an increasing incidence of over 800 cases and 33 deaths reported worldwide. Development of BIA-ALCL is likely a complex process involving many factors, such as the textured implant surface, bacterial biofilm growth, immune response, and patient genetics. As the incidence of BIA-ALCL is expected to increase, it is important for all surgeons and physicians to be aware of this disease entity and acquire thorough knowledge of current evidence-based guidelines and recommendations. Early detection, accurate diagnosis, and appropriate treatment are the foundations of current care.