• 한국생물공학회:학술대회논문집
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• 2003.04a
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• pp.40-44
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• 2003

Soil-borne infectious disease including Pythium aphanidermatum and Rhizoctonia solani causes severe damage to plants, such as cucumber. This soil-borne infectious disease was not controlled effectively by chemical pesticide. Since these diseases spread through the soil, chemical agents are usually ineffective. Instead, biological control, including antagonistic microbe can be used as a preferred control method. An efficient method was developed to select an antagonistic strain to be used as a biological control agent strain. In this new method, surface tension reduction potential of an isolate was included in the ‘decision factor’ in addition to the other factors, such as growth rate, and pathogen inhibition rate. Considering these 3 decision factors by a statistical method, an isolate from soil was selected and was identified as Bacillus sp. GB16. In the pot test, this strain showed the best performance among the isolated strains. The lowest disease incidence rate and fastest seed growth was observed when Bacillus sp. GB16 was used. Therefore this strain was considered as plant growth promoting rhizobacteria (PGPR). The action of surface tension reducing component was deduced as the enhancement of wetting, spreading, and residing of antagonistic strain in the rhizosphere. This result showed that new selection method was significantly effective in selecting the best antagonistic strain for biological control of soil-borne infectious plant pathogen. The antifungal substances against P. aphanidermatum and R. solani were partially purified from the culture filtrates of Bacillus sp. GB16. In this study, lipopeptide possessing antifungal activity was isolated from Bacillus sp. GB16 cultures by various purification procedures and was identified as a surfactin-like lipopeptide based on the Fourier transform infrared spectroscopy (FT-IR), nuclear magnetic resonance (NMR), high performance liquid chromatography mass spectroscopy (HPLC-MS), and quadrupole time-of-flight (Q-TOF) ESI-MS/MS data. The lipopeptide, named GB16-BS, completely inhibited the growth of Pythium aphanidermatum, Rhizoctonia solani, Penicillium sp., and Botrytis cineria at concentrations of 10 and 50 mg/L, respectively. A novel method to prevent the foaming and to provide oxygen was developed. During the production of surface active agent, such as lipopeptide (surfactin), large amount of foam was produced by aeration. This resulted in the carryover of cells to the outside of the fermentor, which leads to the significant loss of cells. Instead of using cell-toxic antifoaming agents, low amount of hydrogen peroxide was added. Catalase produced by cells converted hydrogen peroxide into oxygen and water. Also addition of corn oil as an oxygen vector as well as antifoaming agent was attempted. In addition, Ca-stearate, a metal soap, was added to enhance the antifoam activity of com oil. These methods could prevent the foaming significantly and maintained high dissolved oxygen in spite of lower aeration and agitation. Using these methods, high cell density, could be achieved with increased lipopeptide productivity. In conclusion to produce an effective biological control agent for soil-borne infectious disease, following strategies were attempted i) effective screening of antagonist by including surface tension as an important decision factor ii) identification of antifungal compound produced from the isolated strain iii) novel oxygenation by $H_2O_2-catalase$ with vegetable oil for antifungal lipopeptide production.

• Tuberculosis and Respiratory Diseases
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• v.55 no.4
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• pp.361-369
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• 2003

Background : In Korea, the effort to control the spread of severe acute respiratory syndrome (SARS) has succeeded, but we have to maintain vigilance against SARS and other infectious diseases, because many experts warn that SARS may return or that other infectious agents could spread globally. The purpose of this study is to describe the degree of knowledge of hospital employees, assuming full responsibility for treating and attending to SARS suspected case, and to elucidate the attitude to SARS using questionnaires. Method : All employees of Kangwon university hospital were eligible for this study. We used validated questionnaires to survey demographic characteristics, the degree of knowledge of SARS, intention of treating and attending suspected cases, influence and effects of SARS on the community, and acquisition of information about SARS. Result : Based on the 251 completed surveys, out of 280 returned the score for knowledge about SARS was $72.0{\pm}13.7$, 50.6% responded positively about joining a SARS team, and 23.1% were opposed to the designation for quarantining. There was no relationship between the degree of knowledge of SARS and the attitudes to it. Most employees wanted to know how to manage SARS patients and how to prevent SARS. Conclusion : The attitudes to SARS were not affected by the level of knowledge of SARS. We suggest that national policies about SARS and other infectious diseases should be promulgated using the mass media and internet to provide information on rapidly spreading infectious agents, especially about the proper protocol for treating suspected cases and the appropriate steps to prevent or reduce the risk.

• Asian Pacific Journal of Cancer Prevention
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• v.17 no.6
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• pp.2745-2750
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• 2016

Gastric cancer is a multifactorial and complex malignant disease seen commonly worldwide. It is one of the few malignant conditions in which the etiology involves infectious agents (Helicobacter pylori), but there are many other risk factors incuding high salt intake. Its pathogenesis generally involves interactions between environmental factors and genetic disposition. It is currently onsidered that stem cells may play a central role in gastric cancer development.

• Journal of Life Science
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• v.20 no.9
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• pp.1420-1425
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• 2010

Innate immunity is the first line of host defense consisting of various molecules against infectious challenges. Mannose-binding lectin (MBL) belongs to the collectin protein family which takes part of innate immunity and is able to recognize specific carbohydrates on the surface of a variety of infectious agents acting as a pattern recognition molecule. In this way, MBL differentiates self from non-self and interacts with other molecules of the immune system. MBL genotype shows various MBL2 polymorphisms which are responsible for MBL deficiency in a substantial portion of the entire human population and for susceptibility to infectious disease. Therefore, it has been highlighted in the relationship between genetic variants and clinical significance. Here we focus on presenting anoverview of our understanding of MBL structure and functions.

• Proceedings of the Microbiological Society of Korea Conference
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• 2000.05a
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• pp.94-101
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• 2000

We investigated the viral contamination of water environment including tap water in Korea. River water used for source water was analyzed about monthly between 1997 and 1999 over a period 26 months. A total of 22 tap water samples were collected in 10 sites in 2 urban areas between 1997 and 1998 over a 11 months. All samples were examined for infectious enteroviruses and adenoviruses by a cell culture technique followed by PCR amplification. To identify the recovered viruses from tap water, sequence analysis of PCR products was performed. Infectious viral particles were detected in river water all year round, ranging from 0.93 to 17.3 Most Probable Number of Infectious Unit (MPNIU) /100L. Tap water samples also contained infectious viral particles. The frequency of enteroviruses and adenoviruses in tap water were $50.0\%$ (11/22) and $36.7\%$ (8/22), respectively. Both enteroviruses and adenoviruses were detected in five tap water samples $(22.7\%)$. The level of viral contamination in tap water was quite high, ranging from 0.2 to 2.9 MPNIU/100L, far above the recommended virus level in drinking water set by the U.S. EPA. Poliovirus type 1 derived from vaccine was frequently detected and the remainder comprised coxsackievirus B type or echovirus type 6, which were causative agents of aseptic meningitis in Korea in 1997 and 1998, respectively. Several types of adenovirus were detected in tap water samples and some water samples were found to contain adenoviruses which were closely related to enteric adenovirus type 40 and 41. This stusy shows that surface water and tap water in Korea may be exposed to the risk of viral contamination, especially from recently recognized viruses and this constitutes a potential public health hazard.

• Biomolecules & Therapeutics
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• v.29 no.3
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• pp.282-289
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• 2021

A novel coronavirus, severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), caused a worldwide pandemic. Our aim in this study is to produce new fusion inhibitors against SARS-CoV-2, which can be the basis for developing new antiviral drugs. The fusion core comprising the heptad repeat domains (HR1 and HR2) of SARS-CoV-2 spike (S) were used to design the peptides. A total of twelve peptides were generated, comprising a short or truncated 24-mer (peptide #1), a long 36-mer peptide (peptide #2), and ten peptide #2 analogs. In contrast to SARS-CoV, SARS-CoV-2 S-mediated cell-cell fusion cannot be inhibited with a minimal length, 24-mer peptide. Peptide #2 demonstrated potent inhibition of SARS-CoV-2 S-mediated cell-cell fusion at 1 µM concentration. Three peptide #2 analogs showed IC50 values in the low micromolar range (4.7-9.8 µM). Peptide #2 inhibited the SARS-CoV-2 pseudovirus assay at IC50=1.49 µM. Given their potent inhibition of viral activity and safety and lack of cytotoxicity, these peptides provide an attractive avenue for the development of new prophylactic and therapeutic agents against SARS-CoV-2.

• Biomedical Science Letters
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• v.22 no.3
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• pp.65-74
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• 2016

The critical aspects of biosafety and bio-containment have been increasingly important in recent years. Biological agents involved in biological research projects at the Nanyang Technological University (NTU) Singapore are usually those with low risks. Biosafety level 2 or BSL 2 laboratories are widely used. However, biosafety measures which refer to the implementation of laboratory practices and procedures, specific construction features of laboratory facilities and safety equipment must be in place to reduce the exposure of laboratory personnel, the public or the environment to potentially infectious agents or other biological hazards. It is also required to pay more attention to laboratory-acquired infections (LAIs) which may occur in research laboratories, clinical laboratories or animal facilities. BSL 2 audit and certification program is implemented as an internal exercise covering laboratories in the university where biological agents are handled or biological research works are carried out. We have put some efforts to raise biosafety standards university-wide in both laboratory infrastructure and laboratory practices to a higher level. Common audit findings are briefly discussed in this presentation.

• Journal of Korean society of Dental Hygiene
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• v.9 no.4
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• pp.849-863
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• 2009

Objectives : This study was to study dental hygiene department students' management of infection and their attitude toward infection. Methods : This study was conducted from August 24, 2009 to September 20, 2009. 269 sophomore and junior college students enrolled in the department of dental hygiene from schools located in Gyeonggi-do and Gangwon-do participated in the study. A self-administered questionnaire survey was conducted. Results : 1. As for dental hygiene department students' recognition of the causes of infectious diseases, 80.7% of the respondents said hepatitis B was the infectious disease highly likely to occur in laboratories. 35.3% was correct about the antecedent variables of infection in the workshop, 24.9% about the oral symptoms of HIV and 18.6% about the diseases induced by HBV. The recognition rates were generally low. 2. About whether the respondents ask patients questions about infectious diseases, 80.7% of them answered Yes, but only 56.2% of them said they do so every time, and 17.8% of them said they never do so. 3. As far as washing hands to prevent infectious diseases is concerned, 97.4% of the respondents said hand washing helps prevent infection. 72.5% of them said they wash their hands every time before they practice on a patient, while 84.0% of them said they washed their hands after the lab practice. 90.7% said they use liquid soap containing anti-microbial agents, and 81.8% of them said they use paper towels. 4. With regard to protective gear for prevention of infectious diseases, 98.9% of the respondents said it is desirable to use disposable protective gear for each patient. When it comes to what they actually used as protective gear, 91.1% said aprons, 89.2% gloves, and 87.7% masks. However, a low percentage of the respondents actually use goggles and replace masks when they got damp, 11.2% and 24.2% respectively. Conclusions : As for treating the surface of equipments to prevent infectious diseases, most of the respondents exhibited a high recognition rate. Relative fewer respondents actually treat the surface of equipments than those respondents who are aware of the need to do so. A high percentage of the respondents also said they use alcohol sponge to treat the surface of each equipment in order to prevent infectious diseases.

• Journal of Microbiology
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• v.42 no.4
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• pp.299-304
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• 2004

To investigate the presence of infectious agents in human atherosclerotic arterial tissues. Atherosclerotic plaques were removed from 128 patients undergoing carotid endarterectomy or other bypass proce­dures for occlusive disease, and from twenty normal arterial wall samples, obtained from transplant donors with no history of diabetes, hypertension, smoking, or hyperlipidemia. Using the polymerase chain reaction (PCR) or reverse transcription-PCR, these samples were analyzed for the presence of Chlamydia pneumoniae, cytomegalovirus, enterovirus, adenovirus, herpes simplex viruses types 1 and 2, and Epstein-Barr virus. The amplicons were then sequenced, and phylogenetic analyses were per­formed. Enteroviral RNA was found in 22 of 128 atherosclerotic vascular lesions $(17.2\%),$ and C. pneu­moniae and cytomegalovirus were each found in 2 samples $(1.6\%).$ In contrast, adenovirus, herpes simplex viruses, and Epstein-Barr virus were not identified in any of the atherosclerotic samples. Enterovirus was detected in 6/24 $(25.0\%)$ aortas, 7/33 $(21.2\%)$ carotid arteries, 6/40 $(15.0\%)$ femoral arteries, and 3/31 $(9.7\%)$ radial arteries of patients with chronic renal failure. There were no infectious agents detected in any of the control specimens. Using phylogenetic analysis, the enterovirus isolates were clustered into 3 groups, arranged as echovirus 9 and coxsackieviruses Bl and B3. Enteroviral RNA was detected in $17.2\%$ of atherosclerotic plaques, but was not observed in any of the control spec­imens. This suggests a connection between enteroviral infection and atherosclerosis. These findings dif­fer from those of other studies, which found more frequent incidence of C. pneumoniae and cytomegalovirus infection in atherosclerotic plaques.

• Safety and Health at Work
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• v.14 no.4
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• pp.347-357
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• 2023

Introduction: The COVID-19 pandemic turned biological hazards in the working environment into a global concern. This systematized review of published reviews aimed to provide a comprehensive overview of the specific jobs and categories of workers exposed to biological hazards with the related prevention. Methods: We extracted reviews published in English and French in PubMed, Embase, and Web of Science. Two authors, working independently, subsequently screened the potentially relevant titles and abstracts recovered (step 1) and then examined relevant full texts (step 2). Disagreements were resolved by consensus. We built tables summarizing populations of exposed workers, types of hazards, types of outcomes (types of health issues, means of prevention), and routes of transmission. Results: Of 1426 studies initially identified, 79 studies by authors from every continent were selected, mostly published after 2010 (n = 63, 79.7%). About half of the reviews dealt with infectious hazards alone (n = 38, 48.1%). The industrial sectors identified involved healthcare alone (n = 16), laboratories (n = 10), agriculture (including the animal, vegetable, and grain sectors, n = 32), waste (n = 10), in addition of 11 studies without specific sectors. The results also highlighted a range of hazards (infectious and noninfectious agents, endotoxins, bioaerosols, organic dust, and emerging agents). Conclusion: This systematized overview allowed to list the populations of workers exposed to biological hazards and underlined how prevention measures in the healthcare and laboratory sectors were usually well defined and controlled, although this was not the case in the agriculture and waste sectors. Further studies are necessary to quantify these risks and implement prevention measures that can be applied in every country.