• 한국환경농학회지
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• 제33권4호
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• pp.409-413
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• 2014

BACKGROUND: Large amount of veterinary antibiotics have been used in the livestock industry to prevent diseases and promote growth. These antibiotics are excreted through feces and urine in unchanged form and reach to agricultural fields via application of the livestock manure based composts. The purpose of this study was to evaluate the occurrence of tetracyclines-resistant bacteria in the soil received livestock manure compost for a long term. METHODS AND RESULTS: Tetracyclines (tetracycline TC, chlortetracycline CTC, and oxytetracycline OTC) resistance bacteria in the soil of rice-onion field applied pig manure compost (PM), in the soil of grass-rye field received cow manure compost (CM), and in the soil of rice field applied inorganic fertilizer (NPK) were determined. The soil received livestock manure composts clearly showed higher number of TC, CTC, and OTC resistance bacteria compared with the soil treated with inorganic fertilizer. The antibiotic resistant bacteria recovered appeared at 80 mg/L of tetracyclines was identified 1 specie, 6 genera 7 species, and 6 genera 7species in the soils received CM, PM, and NPK, respectively. The dominant resistant bacteria with the CM and PM application were Ochrobactrum and Rhodococcus. CONCLUSION: The application of livestock manure compost in the agricultural field is likely to contribute the occurrence of antibiotic resistance bacteria in the agricultural environment.

• 한국환경농학회지
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• 제40권4호
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• pp.345-352
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• 2021

BACKGROUND: Salinity is one of the major limiting factors in agriculture that affect the growth and productivity of crops. It is economically difficult to artificially purify the soil affected by salt. Therefore, the use of plant growth-promoting bacteria (PGPB) in an effort to reduce stress caused by salt is emerging as a cost-effective and environment-friendly method. In this study, the purpose was to isolate the salt-tolerant bacteria from the rhizosphere soil and identify their ability to promote plant growth under salt stress condition. METHODS AND RESULTS: The isolates KST-1, KST-2, AST-3, and AST-4 that showed plant growth-promoting activity for barley in salt conditions were close to Bacillus cereus (KST-1, KST-2, and AST-4) and Bacillus thuringiensis (AST-3) and showed high salt tolerance up to 7% of additional NaCl to the media. When inoculated to barley, the strains had only minor effect on the length of the barley. However, the concentrations of chlorophyll in the barley leaves were found to be higher from the bacteria-inoculated pots than those from the uninoculated control. In particular, the chlorophyll concentration in Bacillus cereus AST-4 experiment was 5.45 times higher than that of the uninoculated control under the same experimental condition. CONCLUSION(S): The isolated salt-tolerant bacteria were found to influence on chlorophyll concentration of the barley. As represented by the strain AST-4, microbes may suggest a cost-effective and environmentally benign method to alleviate salt stress of crops cultivated in salt-accumulated soils such as reclaimed lands.

• 치위생과학회지
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• 제19권2호
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• pp.107-112
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• 2019

Background: Good oral health is important for systemic body health and quality of life. Spray oral cleansers are increasingly preferred because of their convenience of carrying and the ease of oral hygiene management. In addition, many kinds of oral cleanser products containing various ingredients with antibacterial, washing, and moisturizing effects are being manufactured. However, concerns about the safety and side effects of oral sprays are increasing, and there is very little information regarding the use and care of oral sprays is available to consumers. This study aimed to investigate the effects of oral spray on oral bacteria and tissue to elucidate the factors that need to be considered when using oral sprays. Methods: The effects of oral spray on the growth of dental plaque bacteria was assessed using disk diffusion assays. Cytotoxicity and morphological changes in oral epithelial cells were observed by microscopy. The effects of oral spray on dental plaque growth were also confirmed on specimens from permanent incisors of bovines by Coomassie staining. Results: The pH of spray products, such as Perioe Dental Cooling, Cool Sense, and Dentrix, were 3.65, 3.61, and 6.15, respectively. All tested spray products showed strong toxicity to dental plaque bacteria and oral epithelial cells. Compared with those on the control, dental plaque bacteria deposits on the enamel surface increased following the use of oral spray. Conclusion: Three types of oral spray, namely Perioe Dental Cooling, Cool Sense, and Dentrix, strongly inhibited the growth of dental plaque bacteria and oral epithelial cells. The oral spray ingredient enhanced dental plaque growth on the enamel surface. Users should be informed of precautions when using oral sprays and the need for oral hygiene after its use.

• 한국물환경학회지
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• 제29권6호
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• pp.777-781
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• 2013

Ion-exchange technology is one of the best for removing nitrate from drinking water. However, problems related to the disposal of spent brine from regeneration of exhausted resins must be overcome so that ion exchange can be applied more widely and economically, especially in small communities. In this background, a combined bio-regeneration and ion-exchange system was operated in order to prove that nitrate-laden resins could be bio-regenerated through direct contact with denitrifying bacteria. A nitrate-selective A520E resin was successfully regenerated by denitrifying bacteria. The bio-regeneration efficiency of nitrate-laden resins increased with the amount of flow passed through the ion-exchange column. When the fully exhausted resin was bio-regenerated for 5 days at the flowrate of 30 BV/hr and MLSS concentration of $125{\pm}25mg/L$, 97.5% of ion-exchange capacity was recovered. Measurement of nitrate concentrations in the column effluents also revealed that less than 5% of nitrate was eluted from the resin during 5 days of bio-regeneration. This result indicates that the main mechanism of bio-regeneration is the direct reduction of nitrate by denitrifying bacteria on the resin.

• Fisheries and Aquatic Sciences
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• 제21권12호
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• pp.36.1-36.11
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• 2018

Background: To confirm whether shellfish are suitable for consumption, the quality of seawater and shellfish in shellfish-producing areas must be assessed regularly. This study was conducted to evaluate the bacterial quality on the Changseon area, containing a designated shellfish-producing area, in Korea during 2011-2013. Result: Even though many inland pollutants near the area were identified, they showed no significant impact on the designated area and the shellfish therein. The concentrations of fecal bacteria in all the seawater and mussel samples from the designated area during the harvesting season were within the standards of various countries. Pathogenic bacteria were not detected in any of the mussel samples. In our previous study, the hazardous metal levels in all the mussels from the same area were also within the limits of different countries. Conclusion: The mussel products in this area are suitable for consumption based on fecal pollution, pathogenic bacteria, and also heavy metals.

• 한국환경농학회지
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• 제38권4호
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• pp.219-224
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• 2019

BACKGROUND: Soil bacteria play important roles in organic matter decomposition and nutrient cycling during the non-growing season. The purpose of this study was to investigate the effects of soil management and chemical properties on the utilization of carbon sources by soil bacteria in paddy fields. METHODS AND RESULTS: The Biolog EcoPlate was used for analyzing community-level carbon substrate utilization profiles of soil bacteria. Soils were collected from the following three types of areas: plain, interface and mountain areas, which were tested to investigate the topology effect. The results of canonical correspondence analysis and Kendall rank correlation analysis showed that soil C/N ratio and NH₄⁺ influenced utilization of carbon sources by bacteria. The utilization of carbohydrates and complex carbon sources were positively correlated with NH₄⁺ concentration. Cultivated paddy fields were compared with adjacent abandoned fields to investigate the impact of cultivation cessation. The level of utilization of putrescine was lower in abandoned fields than in cultivated fields. Monoculture fields were compared with double cropping fields cultivated with barley to investigate the impact of winter crop cultivation. Cropping system altered bacterial use of carbon sources, as reflected by the enhanced utilization of 2-hydroxy benzoic acid under monoculture conditions. CONCLUSION: These results show that soil use intensity and topological characteristics have a minimal impact on soil bacterial functioning in relation to carbon substrate utilization. Moreover, soil chemical properties were found to be important factors determining the physiological profile of the soil bacterial community in paddy fields.

• 한국환경농학회지
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• 제39권1호
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• pp.20-25
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• 2020

BACKGROUND: Marine algae is a productive organism that is consumed as a nutritious food. However, large amounts of unused portions of the algae are incinerated as trash or dumped in the sea, causing pollution. Recycling algae is important for saving resources and conserving the environment. In this study, the fucoidan which is a major carbohydrate of marine algae was tested as a source of fertilizer for farming. METHODS AND RESULTS: The growth rate of the melon was examined after treating fucoidan and the melon growth factors, weight and length of stem were measured. To discover the mechanism of melon growth promotion of fucoidan, bacteria that decomposed fucoidan were isolated from soil and abalone. Bacillus wiedmannii and Stenotrophomonas pavanii were isolated from terrestrial soil and Pseudomonas sp. was isolated from abalone. Among these three bacteria, Pseudomonas sp. had the highest and most specific fucoidan-decomposing activity. When Pseudomonas sp. was treated with fucoidan on melon-growing soil, the growth of melon was relatively improved compared to the treatment with fucoidan alone. CONCLUSION: We found that fucoidan, the main carbohydrate of marine algae, promoted melon growth. Fucoidan-decomposing microorganisms were isolated from terrestrial soil and marine organism, and we found that these bacteria stimulated the effect of melon growth promotion of marine algae. This is the first report that confirms the fertilizer effect of marine algae and shows the use of bacteria with marine algae.

• Safety and Health at Work
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• 제6권1호
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• pp.62-70
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• 2015

Background: Animal skin provides an ideal medium for the propagation of microorganisms and it is used like raw material in the tannery and footware industry. The aim of this study was to evaluate and identify the microbial load in oropharyngeal mucosa of tannery employees. Methods: The health risk was estimated based on the identification of microorganisms found in the oropharyngeal mucosa samples. The study was conducted in a tanners group and a control group. Samples were taken from oropharyngeal mucosa and inoculated on plates with selective medium. In the samples, bacteria were identified by 16S ribosomal DNA analysis and the yeasts through a presumptive method. In addition, the sensitivity of these microorganisms to antibiotics/antifungals was evaluated. Results: The identified bacteria belonged to the families Enterobacteriaceae, Pseudomonadaceae, Neisseriaceae, Alcaligenaceae, Moraxellaceae, and Xanthomonadaceae, of which some species are considered as pathogenic or opportunistic microorganisms; these bacteria were not present in the control group. Forty-two percent of bacteria identified in the tanners group are correlated with respiratory diseases. Yeasts were also identified, including the following species: Candida glabrata, Candida tropicalis, Candida albicans, and Candida krusei. Regarding the sensitivity test of bacteria identified in the tanners group, 90% showed sensitivity to piperacillin/tazobactam, 87% showed sensitivity to ticarcillin/clavulanic acid, 74% showed sensitivity to ampicillin/sulbactam, and 58% showed sensitivity to amoxicillin/clavulanic acid. Conclusion: Several of the bacteria and yeast identified in the oropharyngeal mucosa of tanners have been correlated with infections in humans and have already been reported as airborne microorganisms in this working environment, representing a health risk for workers.

• 한국환경농학회지
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• 제34권3호
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• pp.244-251
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• 2015

BACKGROUND: Recent studies have described the importance of bacteria that can degrade polycyclic aromatic hydrocarbons (PAHs). Here we screened bacterial isolates from commercial gasoline for PAH degraders and characterized their ability to degrade PAHs, lipids and proteins as well as their enantioselective epoxide hydrolase activity, salt tolerance, and seawater survival. METHODS AND RESULTS: One hundred two bacteria isolates from commercial gasoline were screened for PAH degraders by adding selected PAHs on to the surface of agar plates by the sublimation method. A clear zone was found only around the colonies of PAH degraders, which accounted for 13 isolates. These were identified as belonging to Bacillus sp., Brevibacterium sp., Micrococcus sp., Corynebacterium sp., Arthrobacter sp., and Gordonia sp. based on 16S rRNA sequences. Six isolates belonging to Corynebacterium sp., 3 of Micrococcus sp., Arthrobacter sp. S49, and Gordonia sp. H37 were lipid degraders. Arthrobacter sp. S49 was the only isolate showing high proteolytic activity. Among the PAH-degrading bacteria, Arthrobacter sp. S49, Brevibacterium sp. S47, Corynebacterium sp. SK20, and Gordonia sp. H37 showed enantioselective epoxide hydrolase activity with biocatalytic resolution of racemic styrene oxide. Among these, highest enantioselective hydrolysis activity was seen in Gordonia sp. H37. An intrinsic resistance to kanamycin was observed in most of the isolates and Corynebacterium sp. SK20 showed resistance to additional antibiotics such as tetracycline, ampicillin, and penicillin. CONCLUSION: Of the 13 PAH-degraders isolated from commercial gasoline, Arthrobacter sp. S49 showed the highest lipid and protein degrading activity along with high active epoxide hydrolase activity, which was the highest in Gordonia sp. H37. Our results suggest that bacteria from commercial gasoline may have the potential to degrade PAHs, lipids, and proteins, and may possess enantioselective epoxide hydrolase activity, high salt tolerance, and growth potential in seawater.

• 대한간호
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• 제37권2호
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• pp.77-86
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• 1998

Yeung Nam University Medical Center, Department Of Central medical Supply Background: The adverse effect of intravenous therapy combined with various complications. Because sterilization technique and appropriate nursing care can prevent various complications, it is important to use appropriate sponge in intravenous therapy. The purpose of study was to identy sterilization effect and detection of bacteria and to provide basic data for use of appropriate disinfectants. Methods: From May 15 1995 to Aug. 3. 1995, disinfectants that were used in Yeung Nam University Medical Center were tested by bacteria culture. To test sterilization effect of disinfectants of intravenous injection sites after disinfection, 10 subjects were used and were tested by bacteria culture for the study. Results: 1) By sterilization effect of disinfectants, bacteria were increased from 103 to 10 from 48 hours in both 2% Zephanon and 2% zephanon that was sterilized by steam, from 10 to 10 from 72 hours and 10 from 48 hours in 70% lsoprophyl alchol. Also, bacterias were detected in 70% lsoprophyl alchol on 48 hours. 2) By stenlization effect of sponge that were used in nursing unit, bacterias were detected in 2% Zephanon on 2 hours, 70% lsoprophyl alchol on 2 hours, 70% lsoprophyl alchol on 8 hours and 70% lsoprophyl alchol on 48 hours. 3) By sterilization effect and detection of bacteria of intravenous site after disinfection, bacterias were detected in 10 of 10 control groups, 8 of 10 sites that were disinfected by steam sterilized 2% zephanon sponge, 6 of 10 sites that were disinfected by 70% lsoprophyl alchol and 4 of 10 sites that were disinfected by 10% Batadine. Conclusions : it is conclued that 70% lsoprophyl alchol is appropriate for intravenous therapy and 10% Betadine is appropriate in ward that were polluted the air and in immunodeficient patients.