• 한국환경농학회지
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• 제30권4호
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• pp.424-431
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• 2011

본 연구에서 우리는 광양만의 해수와 표층 퇴적물에서 TBTCl 내성세균의 개체수를 조사하였다. 광양만에서 TBTCl 내성세균의 개체수는 해수에서 $2.5{\times}10^3-3.8{\times}10^3$ cfu/mL 범위였으며, 표층 퇴적물에서 TBTCl 내성세균의 개체수는 $3.2{\times}10^5-9.1{\times}10^5$ cfu/g 범위였다. 광양만에서 TBTCl 내성세균의 종조성은 Vibrio spp. (19.2%)가 가장 높은 우점종으로 나타났고, Bacillus spp. (16.2%), Aeromonas spp. (15.2%), Pseudomonas spp. (13.1%), Klebsiella spp. (11.1%), Alteromonas spp. (9.1%), Pantoea spp. (6.1%), Proteus spp. (3.0%), Listeria spp. (2.0%), unidentified (5.0%)의 순으로 우점하였다. 또한 11개의 대표적인 TBTCl 내성균주는 여러 중금속들(Cd, Cu, Hg 및 Zn)에도 내성을 나타내었다. 이들 중에서 가장 강한 TBTCl 내성을 보이는 T7 균주를 선별하여, API 20NE등을 이용하여 본 균주의 형태학적, 생리학적 및 생화학적 특성들을 조사하였다. T7 균주는 16S rRNA gene 염기서열 분석에 의해 Pantoea 속으로 동정되어 Pantoea sp. T7으로 명명되었다. 또한 본 균주는 $500{\mu}M$의 TBTCl 농도에서도 60시간 배양 후에 정상 균주 성장의 50.7%까지 증식하였다. Pantoea sp. T7의 생물학적 TBTCl 분해활성은 GC-FPD 분석에 의해 측정되었는데, $100{\mu}M$의 TBTCl 농도에서 배양 40시간 후에 TBTCl 제거 효율은 62.7%로 나타났다.

• 생체재료학회지
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• 제22권4호
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• pp.328-336
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• 2018

Background: Biogenic fabrication of silver nanoparticles from naturally occurring biomaterials provides an alternative, eco-friendly and cost-effective means of obtaining nanoparticles. It is a favourite pursuit of all scientists and has gained popularity because it prevents the environment from pollution. Our main objective to take up this project is to fabricate silver nanoparticles from lichen, Usnea longissima and explore their properties. In the present study, we report a benign method of biosynthesis of silver nanoparticles from aqueous-ethanolic extract of Usnea longissima and their characterization by ultraviolet-visible (UV-vis), Fourier transform infrared (FTIR) spectroscopy, transmission electron microscopy (TEM) and scanning electron microscopy (SEM) analyses. Silver nanoparticles thus obtained were tested for antimicrobial activity against gram positive bacteria and gram negative bacteria. Results: Formation of silver nanoparticles was confirmed by the appearance of an absorption band at 400 nm in the UV-vis spectrum of the colloidal solution containing both the nanoparticles and U. longissima extract. Poly(ethylene glycol) coated silver nanoparticles showed additional absorption peaks at 424 and 450 nm. FTIR spectrum showed the involvement of amines, usnic acids, phenols, aldehydes and ketones in the reduction of silver ions to silver nanoparticles. Morphological studies showed three types of nanoparticles with an abundance of spherical shaped silver nanoparticles of 9.40-11.23 nm. Their average hydrodynamic diameter is 437.1 nm. Results of in vitro antibacterial activity of silver nanoparticles against Staphylococcus aureus, Streptococcus mutans, Streptococcus pyrogenes, Streptococcus viridans, Corynebacterium xerosis, Corynebacterium diphtheriae (gram positive bacteria) and Escherichia coli, Klebsiella pneuomoniae and Pseudomonas aeruginosa (gram negative bacteria) showed that it was effective against tested bacterial strains. However, S. mutans, C. diphtheriae and P. aeruginosa were resistant to silver nanoparticles. Conclusion: Lichens are rarely exploited for the fabrication of silver nanoparticles. In the present work the lichen acts as reducing as well as capping agent. They can therefore, be used to synthesize metal nanoparticles and their size may be controlled by monitoring the concentration of extract and metal ions. Since they are antibacterial they may be used for the treatment of bacterial infections in man and animal. They can also be used in purification of water, in soaps and medicine. Their sustained release may be achieved by coating them with a suitable polymer. Silver nanoparticles fabricated from edible U. longissima are free from toxic chemicals and therefore they can be safely used in medicine and medical devices. These silver nanoparticles were stable for weeks therefore they can be stored for longer duration of time without decomposition.

• 대한세포병리학회지
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• 제3권2호
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• pp.100-103
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• 1992

We experienced a case of primary hepatic actinomycosis which was initially diagnosed by means of fine needle aspiration. The patient was a 31-year-old emaciated man with a 2-month history of 10 kg weight loss, right upper quadrant pain and flank pain. The liver was palpable and tender on physical examination. Computerized tomography scan of the liver showed two ill-defined hypodense masses in gallbladder fossa and inferior pole of right lobe. Hepatocellular carcinoma was clinically suspected. A CT-guided fine needle aspiration was peformed. Microscopically, smears showed numerous radiating clusters of filamentous bacteria with many neutrophils and monocytes in necrotic background. The symptoms were improved by incision and drainage and massive administration of penicillin.

• IMMUNE NETWORK
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• 제5권4호
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• pp.199-204
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• 2005

Background: ADP-ribosyl pyrophosphatases (ADPRase) has been known to catalyze the hydrolysis of ADP-ribose to ribose-5-phosphate and AMP. The role of ADPRase has been suggested to sanitize the cell by removing potentially toxic ADP-ribose. In this study, we examined the effect of nitric oxide on ADPRase activity in macrophages. Methods: ADPRase activity was measured in NO-inducing J774 cells. For in vitro experiments, recombinant human ADPRase was prepared in bacteria. Results: ADPRase activity was increased by the treatment of exogenous NO generating reagent, sodium nitroprusside (SNP), in J774 cells. The increased ADPRase activity was mediated by the post-translational modification, likely to cause cADP-ribosylation via nitrosylation of cysteine residue on the enzyme. The stimulation with endogeneous NO inducers, $TNF-{\alpha}/IFN-{\gamma}$, also increased ADPRase activity through NO synthesis. Futhermore, ADPRase activity may be mediated by the post-translational modification of ADPRase, ADP-ribosylation. Conclusion: These results indicate that NO synthesized by macrophage activation plays a critical role in the increase in ADPRase activity following ADP-ribose metabolism.

• Journal of Electrical Engineering and Technology
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• 제5권3호
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• pp.484-492
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• 2010

Magnetic switch is a kind of saturable inductor, which utilizes nonlinearity of the magnetization curve of ferromagnetic materials. The right understanding of the saturation phenomena, magnetic properties, voltage-time product, and switching characteristics of the magnetic switch is essential in designing the magnetic pulse compressor (MPC). In this paper, the historical background of research on the MPC, fundamental physical properties of the magnetic switches, and application fields of the MPC are presented. Further, an in-depth analysis of pulse compression in series and parallel MPCs is incorporated. As practical application examples, a series MPC used for water treatments and a parallel MPC used for pulsed electric field (PEF) inactivation of bacteria are cited.

• The Plant Pathology Journal
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• 제37권5호
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• pp.489-493
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• 2021

Bacterial canker is a devastating disease of kiwifruit caused by the bacterium Pseudomonas syringe pv. actinidiae. Canker disease of kiwifruit in Korea has been controlled using streptomycin for more than two decades. Four streptomycin-resistant strains, belonging to biovar 2, which are found only in Korea, were collected between 2013 and 2014 from different orchards located in Jeju, Korea. The genetic background for streptomycin resistance among P. syringe pv. actinidiae strains were determined by examining the presence of strA-strB or aadA, which are genes frequently found in streptomycin-resistant bacteria, and a point mutation at codon 43 in the rpsL gene. All four streptomycin-resistant strains of P. syringe pv. actinidiae investigated in this study contained strA-strB as a resistant determinant. The presence of the aadA gene and a mutation in codon 43 of the rpsL gene was not identified.

• 한국의료질향상학회지
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• 제3권2호
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• pp.26-35
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• 1997

Background : Glycopeptide antibiotics are the only drugs for treatment of infections due to beta-lactam-resistant Gram-positive bacteria. As the incidence of infection and colonization with vancomycin-resistant enterococci(VRE) rapidly increases, the hospital infection control practices advisory committee(HICPAC) recommends prudent vancomycin use to detect, prevent and control infection and colonization with VRE. Methods : The inpatients admitted from September to December, 1996 in Pusan National University Hospital, with Gram-positive bacterial infections were evaluated retrospectively to see whether the administrations of glycopeptide antibiotics were appropriate or not, upon comparison with the recommendations for preventing the spread of vancomycin resistance by HICPAC. Results : Teicoplanin has been chosen more frequently than vancomycin of the glycopeptide antibiotics. The indications of administration of glycopeptides in patients with pneumonia, wound infections, sepsis, and in febrile or neutropenic patients with malignancies were appropriate, but the use of glycopeptides for elimination of merely colonized bacteria in the oral cavity could not be excluded. Inappropriate use of glycopeptides was 10.6%, and inappropriately long-term use without positive culture for beta-lactam-resistant Gram-positive organisms was about 40% of total days of drug use. Conclusion : It seems essential for the quality assurance committee to make a plan in teaching the HICPAC recommendations to the medical practitioners who prescribed the glycopeptides inappropriately or used for irrelevantly long to his patient, monitor and survey their use of glycopeptides prospectively and periodically, and if there are repeated inappropriate prescriptions, a certain penalty would be given to the practitioners.

• Tuberculosis and Respiratory Diseases
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• 제74권2호
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• pp.63-69
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• 2013

Background: Aiming to improve outcome of lung transplantation (LTx) patients, we reviewed risk factors and treatment practices for the LTx recipients who experienced respiratory infection in the late post-LTx period (>1 month after LTx). Methods: We analyzed the clinical data of 48 recipients and donors from 61 LTx, who experienced late respiratory infections. Late respiratory infections were classified according to the etiology, time of occurrence, and frequency of donor-to-host transmission or colonization of the recipient prior to transplantation. Results: During the period of observation, 42 episodes of respiratory infections occurred. The organisms most frequently involved were gram (-) bacteria: Acinetobacter baumannii (n=13, 31.0%), Pseudomonas aeruginosa (n=7, 16.7%), and Klebsiella pneumoniae (n=4, 10.0%). Among the 42 episodes recorded, 14 occurred in the late post-LTx period. These were bacterial (n=6, 42.9%), fungal (n=2, 14.3%), viral (n=4, 28.5%), and mycobacterial (n=2, 14.3%) infections. Of 6 bacterial infections, 2 were from multidrug-resistant (MDR) A. baumannii and one from each of MDR P. aeruginosa, extended spectrum ${\beta}$-lactamase (+) K. pneumoniae, methicillin-resistant Staphylococcus aureus and Streptococcus pneumoniae. Infection-related death occurred in 6 of the 14 episodes (43%). Conclusion: Although the frequency of respiratory infection decreased sharply in the late post-LTx period, respiratory infection was still a major cause of mortality. Gram (-) MDR bacteria were the agents most commonly identified in these infections.

• 한국환경농학회지
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• 제38권4호
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• pp.269-272
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• 2019

BACKGROUND: Since 2015, fire blight disease caused by Erwinia amylovora has been devastating apple and pear orchards every year. To quickly block the disease spreading, infected apple and pear trees have been buried in soil. However, concern on the possibility of the pathogen survival urgently requires informative data on the buried host plants. Therefore, this study was conducted to investigate the survival of the pathogen from the buried host plants. METHODS AND RESULTS: Apple trees buried in 42 months ago in a Jecheon site and pear trees buried in 30 months ago in an Anseong site were excavated using an excavator. Plant samples were taken from stems and twigs of the excavated trees. The collected 120 samples were checked for rotting and used for bacterial isolation, using TSA, R2A, and E. amylovora selection media. The purely isolated bacteria were identified based on colony morphology and 16S rDNA sequences. Wood rotting and decay with off smells and discoloring were observed from the samples. A total of 17 genera and 48 species of bacteria were identified but E. amylovora was not detected. CONCLUSION: Our investigation suggests that the survival of E. amylovora doesn't seem possible in the infected hosts which have been buried in soil for at least 30 months. Therefore, the burial control can be considered as a safe method for fire blight disease.

• 치위생과학회지
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• 제19권4호
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• pp.213-219
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• 2019

Background: Smoking exerts an adverse effect on the periodontal tissue by reorganizing the ecosystem of oral microorganisms and is considered to be an important factor in the development of periodontal disease. Although cross-sectional studies on smokers and non-smokers have been attempted to investigate the microbial differences in periodontal oral cavity, only few studies have been conducted to investigate the changes in oral microorganisms during smoking cessation. The purpose of this study was to investigate the changes of bacteria in saliva and gingival crevicular fluid (GCF) over a period of one year among 11 smokers trying to quit smoking. Methods: Eleven smokers trying to quit smoking visited the clinic at baseline, two weeks, two months, four months, six months, and 12 months to give saliva and GCF samples. The amounts of 16S rRNA, Porphyromonas gingivalis, Treponema denticola, Prevotella intermedia, Fusobacterium nucleatum subsp. nucleatum, Streptococcus mutans, and Streptococcus sobrinus in saliva and GCF were quantified using real-time polymerase chain reaction TaqMan probe assay. The results were analyzed by nonparametric statistical analysis using Friedman test and Spearman correlation coefficient. Results: After cessation of smoking, the amounts of 16S rRNA corresponding to P. gingivalis, F. nucleatum, P. intermedia, and T. denticola in saliva decreased and then again increased significantly. The amount of F. nucleatum 16S rRNA in GCF decreased significantly after smoking cessation. Positive correlations were observed between 16S rRNA and F. nucleatum and between F. nucleatum and T. denticola in saliva and GCF. Conclusion: Even if the number of subjects in this study was small, we suggest that smoking cessation may reduce the total bacterial amount and F. nucleatum in GCF. However, the results regarding changes in the microbial ecosystem due to smoking or smoking cessation were inconsistent. Therefore, further in-depth studies need to be carried out.