• Korean Journal of Fisheries and Aquatic Sciences
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• v.51 no.4
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• pp.389-396
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• 2018

Marine pathogenic bacteria, such as Streptococcus parauberis, Edwardsiella tarda and Vibrio harveyi, can cause lethal infections in farmed fish, ozone and antibiotics, are employed to sterilize waters used for rearing fish to mitigate this threat. The most widely used method is treatment with sodium hypochlorite solution. However, the maintenance of a constant concentration of chlorine in rearing waters can be difficult. We investigated the potential of a mixed oxidant (MO) solution generated by electrolysis of sea water to improve water quality. We measured the survival rates of fish pathogenic bacteria exposed to different concentrations of MO (0.5, 1.0, 1.5 and 2.0 MO) and sodium hypochlorite (0.5, 1.0, 1.5 and 2.0 ppm) for various lengths of time (0, 5, 10, 15, 20, 25 and 30 min). We found a time-dependent decrease in the survival rates of the tested pathogenic microorganisms. The sterilization effect of the MO solution on pathogenic organisms was greater than that of sodium hypochlorite for gram-negative and gram-positive bacteria. We conclude that MO solution produced by electrolysis could be used to maintain a constant chlorine concentration in aquaculture systems.

• Korean Journal of Environmental Biology
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• v.20 no.3
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• pp.189-196
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• 2002

The direct detection of intestinal pathogens and viruses often requires costly, tedious, and time-consuming procedures. These requirements developed a test to show that the water was contaminated with sewage-borne pathogens by assessing the hygienic quality of water based on indicator microorganisms whose presence indicates that pathogenic microorganisms may also be present. Various groups of microorganisms have been suggested and used as indicator microorganisms. Proposed and commonly used microbial indicators are total coliforms, fecal coliforms, fecal streptococci, Clostridium perfringens, heterotrophic plate count, bacteriophage, and so on. Unfortunately, most, if not all, of these indicators are not ideal because of the sensitivity and resistance to environment stresses and disinfection. However, the development of gene probes and PCR technology may give hope for the discovery of rapid and simple methods toy detecting small number of fecal pathogens in various environments.

• Food Science and Biotechnology
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• v.18 no.5
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• pp.1243-1252
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• 2009

User-friendly software was developed to determine the shelf-life of perishable Korean seasoned side dishes in real time based on growth models of spoilage and pathogenic microorganisms. In the program algorithm, the primary spoilage and fastest-growing pathogenic organisms are selected according to the product characteristics, and their growth is simulated based on the previously monitored or recorded temperature history. To predict the growth of spoilage organisms with confidence limits, kinetic models for aerobic bacteria or molds/yeasts from published works are used. Growth models of pathogenic bacteria were obtained from the literature or derived with regression of their growth rate data estimated from established software packages. These models are also used to check whether the risk of pathogenic bacterial growth exceeds that of food spoilage organisms. Many example simulations showed that the shelf-lives of the examined foods are predominantly limited by the growth of spoilage organism rather than by pathogenic bacterial growth.

• Journal of Food Hygiene and Safety
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• v.21 no.3
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• pp.145-152
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• 2006

Efforts have been made to explore the possibility of using garlic as an antimicrobial therapeutic agent since garlic extract and its individual sulfur compounds show antimicrobial activities against all kinds of microorganisms including bacteria, molds, yeasts and protozoa. Staphylococcus aureus has been the most studied bacteria along with many other Gram positive and negative pathogenic bacteria, including species of the genera Clostridium, Mycobacterium, Escherichia, Klebsiella, Bacillus, Salmonella and Shigella. Candida albicans has been the most studied among the eukaryotic microorganisms. A pathogenic protozoa, Giardia intestinalis, was also tested. All the microorganisms tested was inhibited by garlic extract or its sulfur components. Garlic has been known to be growth inhibitory only when fresh garlic is crushed, since allicin-generating reaction is enzyme-catalyzed. Allicin is known to be growth inhibitory through a non-specific reaction with sulfhydryl groups of enzyme proteins that are crucial to the metabolism of microorganisms. Another plausible hypothesis is that allicin inhibits specific enzymes in certain biological processes, e.g. acetyl CoA synthetase in fatty acid synthesis in microorganisms. Allicin transforms into other compounds like ajoene and various sulfides which are also inhibitory to microorganisms, but not as potent as their mother compound. It is reported recently that garlic heated at cooking temperatures is growth inhibitory especially against yeasts, and that the growth inhibitory compound is allyl alcohol thermally generated from alliin in garlic.

• Journal of Animal Environmental Science
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• v.10 no.2
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• pp.111-118
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• 2004

This study analyzed temperature increase, microorganism changes, and inactivation of pathogenic microorganisms in pig slurry when treated with thermophilic microorganisms in Thermophilic Aerobic Oxidation(TAO) system. An amount of $6 m^3$ of pig slurry was treated in an $18 m^3(3.0\times2.5\times2.4 m)$ reactor for 5 to 7 days in two groups: the control of pig slurry only and the treatment of pig slurry with 6 liters of thermophilic microorganism(Bacillus sp.). To study the microorganism changes in the reactor, the populations of aerobic mesophilic microorganisms, thermophilic microorganisms and general pathogens were analyzed. To study the inactivation of pathogenic microorganisms, the levels of E. coli, Salmonella sp, Crytosporidium parvum and Giardia lamblia were analyzed. The temperature inside the reactor ranged from 18 to $62^{\circ}C$ for the control while far the treatment group it ranged from 18 to $66^{\circ}C$, showing a slightly higher array. With regard to changes in microorganisms, both mesophilic and thermophilic organisms decreased from $3.1\times10^6$ to $1.2\times10^2$ CFU/ml and from $1.0\times10^4$ to $8.0\times10^1$ CFU/ml, respectively, in the control. In the treatment, on the other hand, mesophilic organisms decreased from $3.0\times10^8$ CFU/ml to $8.6\times10^5$ CFU/ml while thermophilic organisms increased sharply from $2.0\times10^6$ to $1.2\times10^8$ CFU/ml. For pathogens, Salmonella and Giardia were not detected either before or after the treatment, while E. coli and C. parvum were found to be $10^5$ CFU/ml each before treatment and negative after it. From this experiment, it was concluded that thermophilic microorganisms could effectively sanitize liquid compost by generating high temperature in the TAO system, which in turn would inhibit the growth of pathogenic organisms.

• Journal of Microbiology and Biotechnology
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• v.16 no.3
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• pp.349-354
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• 2006

Furaneol, a key aroma compound found in strawberry, pineapple, and processed foodstuffs, has been known to possess various biological activities on animal models. In this study, the antimicrobial effects of furaneol against human pathogenic microorganisms were investigated. The results indicated that furaneol displayed a broad spectrum of antimicrobial activities against Gram-positive and Gram-negative bacteria and fungi without hemolytic activity on human erythrocyte cells. To confirm the antifungal activity of furaneol, we examined the accumulation of intracellular trehalose as a stress response marker on toxic agents and its effect on dimorphic transition of Candida albicans. The results demonstrated that furaneol induced significant accumulation of intracellular trehalose and exerted its antifungal effect by disrupting serum-induced mycelial forms. These results suggest that furaneol could be a therapeutic agent having a broad spectrum of antimicrobial activity on human pathogenic microorganisms.

• The Korean Journal of Mycology
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• v.31 no.2
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• pp.67-76
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• 2003

This study was performed to screen antimicrobial activities of 198 extracts from 66 Korean mushrooms against 19 human pathogenic microorganisms using paper disc method. Mushrooms were extracted with petroleum ether 80% ethanol and distilled water in that order Among the extracts with antimicrobial activities, 1 water extract of Amanita virgineoides, 8 ethanolic extracts including Amanita and 1 petroleum ether extrac of Psathyrella hydrophila were highly active against fungi, respectively. In addition to, 24 extracts including Amanita pseudoporphyria, Amanita spissacea, 3 extaracts including Paxillus curtisii were highly active against Gram negative and positive bacteria, respectively.

• Natural Product Sciences
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• v.17 no.2
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• pp.160-164
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• 2011

The purpose of this investigation was to extract the bioactive agents from Alpinia officinarum Hance. The methanol with ethylacetate extracts alone and combined were examined for their activities against VRE (vancomycin-resistant enterococci) and pathogenic yeast in vitro. The incidence of infections caused by VRE and other pathogenic microorganisms and the importance of using novel synergistic drug combinations has become important. Previously, we reported the antimicrobial effects of the butanol extract from Lonicera japonica and have evaluated combinations of solvent extracts, with a focus on the MeOH and EtOAc extracts from A. officinarum. In the present study, enhanced inhibitory effects were achieved by employing a combination of the two solvent extracts. The MeOH and EtOAc combination was especially effective against four VRE strains: E. faecalis (K-10-22), E. faecaium (K-11-212), E. faecalis (K-10-57) and E. faecalis (K-10-361) with MIC values of 12.5, 12.5, 6.25 and 25 ${\mu}g/ml$, respectively. Thus, the combination was more effective than other antibiotics such as kanamycin, gentamicin or tetracycline against bacteria including E. coli, Staphylococcus aureus, and Micrococcus luteus. In addition, the combination was effective against yeasts such as Candida albicans, Candida tropicalis and Cryptococcus neoformans.

• Journal of Microbiology
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• v.45 no.1
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• pp.53-57
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• 2007

A number of essential oils from Mongolian aromatic plants are claimed to have antimicrobial activities. The essential oil of Dracocephalum foetidum, a popular essential oil used in Mongolian traditional medicine, was examined for its antimicrobial activity. Eight human pathogenic microorganisms including B. subtilis, S. aureus, M. lutens, E. hirae, S. mutans, E. coli, C. albicans, and S. cerevisiae were examined. The essential oil of Dracocephalum foetidum exhibited strong antimicrobial activity against most of the pathogenic bacteria and yeast strains that were tested; by both the agar diffusion method and the minimum inhibitory concentration (MIC) assay ($MIC\;range\;was\;26-2592{\mu}g/ml$). Interestingly, Dracocephalum foetidum even showed antimicrobial activity against methicilin-resistant Staphylococcus aureus (MRSA) strains. We also analyzed the chemical composition of the oil by GC-MS and identified several major components, including n-Mentha-1,8-dien-10-al, limonene, geranial, and neral.

• Journal of Microbiology and Biotechnology
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• v.23 no.7
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• pp.885-896
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• 2013

2,3-Butanediol (2,3-BDO) has immense industrial applications. Recently, microbial fermentation has emerged as an alternative way to produce this industrially important chemical. Although 2,3-BDO is produced by several microorganisms, the Klebsiella genera has an excellent production compared with other 2,3-BDO-producing microorganisms. In order to produce 2,3-BDO on a large scale, the challenges of removing pathogenic factors from Klebsiella pneumoniae need to be addressed. K. pneumoniae produces a number of virulence factors that contribute to its pathogenesis, including lipopolysaccharides, capsules, fimbrial adhesins, etc. Removal of these pathogenic factors from 2,3-BDO-producing Klebsiella strains will result in avirulent strains for the safe, economic, and efficient production of 2,3-BDO. In this review, we summarize the current trends in 2,3-BDO production using K. pneumoniae and insights into the removal of its virulence factors for industrial applications.