• BMB Reports
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• v.35 no.3
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• pp.291-296
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• 2002

Thanatin, a 21-residue peptide, is an inducible insect peptide with a broad range of activity against bacteria and fungi. It has a C-terminal disulfide loop, like the frog skin secretion antimicrobial peptides of the brevinin family. In this study, we tried to find the effect of a number of amino acids between the disulfide bond. Thanatin showed stronger antibacterial activity to Gram negative bacteria than other mutants, except Th1; whereas, the mutant peptides with deletion had higher activity to Gram positive bacteria than thanatin. An increase in the number of amino acid(s) using the alanine residue decreased the antibacterial activity in all of the bacteria. Th1 with deletion of threonine at position 15 ($Thr^{15}$) showed similar antibacterial activity against Gram-negative bacteria, but had higher activity against the Gram positive bacteria. In order to study the structure-function relationship, we measured liposome disruption by the peptides and CD spectra of the peptides. Th1 also showed the highest liposome leaking activity and α-helical propensity in the sodium dodecyl sulfate solution, compared with other peptides. Liposome disruption activity was closely correlated with the anti-Gram positive bacterial activity. All of the peptides showed no hemolytic activity. Th1 was considered to be useful as an antimicrobial peptide with broad spectrum without toxicity.

• Journal of Marine Life Science
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• v.4 no.2
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• pp.86-90
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• 2019

This study aimed to compare the disinfection efficiencies of the ultraviolet and plasma systems, the two systems designed and commercialized to disinfect water in aquaculture, by putting each in a 100 ℓ water tank and concentrating 1.0 ℓ of treated water to check the changes in the number of bacteria in the samples. Each system was operated for 6 hours to culture the typical seawater bacteria in the Marine agar, Thiosulfate citrate bile salts sucrose agar and Salmonella Shigella agar media, respectively, to check the number of bacteria in the media, and the changes in the number of Edwardsiella piscicida in the treated water were checked after the artificial inoculation of E. piscicida in the disinfected seawater. As a result, the two disinfection systems showed the almost similar levels of bacterial reduction efficiency between 99.5% and 99.9%. However, the result of this study showed that, with 100 ℓ of water treated for the same length of time using the two systems, the plasma system turned out to disinfect bacteria in a shorter period of time than the UV system. However, as the changes in the number of bacteria were checked for a short length of time (6 hours) in this study, it was judged that, considering the actual aquaculture environment in which the quality of water significantly changes with feed residues, excretions and coastal contamination, etc., and a lot of biofilms and organic matter exist, the plasma system would be more efficient than the UV system as the former is capable of continuously maintaining a certain level of efficiency than the latter that is limited in terms of efficiency depending on the level of turbidity and the existence of organic matter.

• Korean Journal of Microbiology
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• v.30 no.5
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• pp.383-390
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• 1992

In the periods of July 31 to August 10. 1988 and March 9 to 13. 1989. sediment samples were collected from the South Sea stations (010] to 092]) located in the area from $N 32^{\circ}$/30' to $34^{\circ}$/30', of latitude and from E $123^{\circ}$ 30' to $128^{\circ}$30' of longitude. These samples were analyzed for the number of total heterotrophic bacteria and extracellular digesting enzyme activities. In the 1989 spring period the number of heterotrophic bacteria in the sediment surface layer was increased more than 100 times at the maximum compared to that in the 1988 summer period. The proportion of fresh water bacteria to total heterotrophic bacteria was also higher in the spring period than the summer period. The extracellular digesting enzyme activities were higher in spring season than summer. Although the water content of sediment in the spring period was lower than that the summer period. the ash weight indicating organic material content was higher. These results means that the diameters of sediment particles were larger in spring than summer but the input of organic material into the sediment was greater. Based on these results bacterial distributions in the sediment layer of South Sea depend greatly on the season due to the effect of fresh water. During the spring season plankton could grow extensively owing to the inorganic nutrients input by the vertical mixing in the water column, then be precipitated into the sediment. Organic nutrients supplied from enzymatic degradation of polymeric particle from plankton can increase the bacterial number, too.

• Food Science of Animal Resources
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• v.39 no.5
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• pp.704-724
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• 2019

This study mainly investigated the improvement effect of nitroso-hemoglobin (NO-Hb) and four lactic acid bacteria (LAB) (Streptococcus thermophiles, Lactobacillus bulgaricus, Lactobacillus casei, and Montessori enterococcus) on the color and microbiological qualities of raw beef. Three strains of Escherichia coli, Staphylococcus, Salmonella, and Pseudomonas were used as pathogenic bacteria. The results showed that both NO-Hb and LAB could enhance the color stability and scavenged the spoilage bacteria in a minced beef model. But the improvement effect of NO-Hb was more significant than LAB. This suggested that NO-Hb, as a novel ingredient, could be used as a promising substitute for nitrite in meat products to improve the color and safety of meat products. In addition, low field (LF)-NMR method has been established to be practicable to identify changes in the relaxation times of water and fat caused by different type of bacteria and the storage periods. The number of relaxation components in minced beef was affected by bacteria and increase of the storage period.

• Journal of Korean Society on Water Environment
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• v.20 no.2
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• pp.170-175
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• 2004

The purpose of this study was to monitor bacteria present in raw water and to investigate the effect of ozone, UV and combined ozone/UV processes for inactivating bacteria. Both polymerase chain reaction (PCR)-fragment length polymorphic analysis (PRA) and PCR-sequence analysis (PSA) were applied for the simultaneous analysis of numerous bacteria species present in each tested water, such as drinking water (DRW), drinking water source (DRWS) and sewage effluent water (SEW). According to the result, the number of detected bacteria species was zero in DRW, 58 in DRWS and 13 in SEW. After treatment of the each process, the ozone/UV process was the most successful for inactivating almost all bacteria. However, it was found that Flavobacterium sp., Pseudomonas sp. and Beta proteobacterium sp. had strong resistant to all tested processes, requiring further detailed study.

• Journal of dental hygiene science
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• v.13 no.2
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• pp.213-221
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• 2013

The mouth rinsing solution currently on the market is used for oral hygiene and reduction of halitosis, and alkaline ionized water is used for drinking purposes. The aim of this germiculture and observation through a microscope is to investigate the effect they have on the oral bacteria, and the results are as follows. 1. The change in the number of cultivated bacteria before and after the use of gargle was most dramatic for Hexamedin. It showed the highest rate of decrease in bacteria by 71.29%, followed by Listerine with 62.25%, Caregargle with 42.26%, Garglin with 33.52%, saline solution with 21.62%, alkaline ionized water with 16.08% and distilled water with 7.67%. 2. After careful analysis of statistics, Hexamedin was found to result in a significant decrease in the number of bacteria after gargling (p<0.05). 3. From observing through an light microscope after gram staining, it was evident that both a number of cocci and a few of filamentous were present before the use of gargle, whereas mostly cocci was present after the use of gargle. 4. The difference in the pH of oral rinses and alkaline ionized water had no significant influence on the number of oral bacteria. In conclusion, Hexamedin and Listerine, with the rate of decrease of bacteria of co71.29% and 62.25% respectively, have proven to be highly effective when applied before dental treatment. Other oral rinses and alkaline ionized water are relatively less efficient in decreasing the number of oral bacteria. Also, the decrease of bacteria is more affected by the antibacterial component of oral rinses than by the change in pH.

• Journal of The Korea Institute of Healthcare Architecture
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• v.30 no.2
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• pp.15-22
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• 2024

Purpose: In general, cross-infection caused by bacteria occurs more in hospitals than in local communities. In most cases, infectious diseases spread through contact transmission (direct contact, indirect contact). This study tries to examine which places are most likely to detect infections bacteria and what materials should be used to effectively suppress the spread of infectious bacteria. Methods: Domestic and international literature have been reviewed to determine which bacteria are common and spread in which places. At the same time, antibacterial experiments for several finishing materials are performed to determine the survival period of bacteria for each material. The experiment is conducted mainly on antibiotic-resistant bacteria (MRSA, CRE, etc.) that have a high mortality rate and are very contagious. Results: MRSA has a high incidence in many hospital departments with surgery or immunocompromised patients, such as the elderly, organ transplant patients, and hemodialysis patients. There are experimental results that MRSA dies early in ceramics or silk wallpaper. CRE has a high incidence in hospital departments where there are many patients who are prone to bacteria entering the body directly, such as ventilator patients or critically ill patients with surgical wounds. There are experimental results that CRE dies early in silk wallpaper. In addition, bacteria die on the surface for a variety of reasons. Most MRSA and CRE develop in patients with impaired immunity or surgery, and rapidly die in copper or materials with antibacterial properties. Implications: If finishing materials surface with the ability to kill specific bacteria is used in the place where a large number of specific bacteria are detected, the spread of infectious diseases can be effectively controlled.

• Korean Journal of Soil Science and Fertilizer
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• v.21 no.2
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• pp.135-140
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• 1988

A laboratory experiment was conducted to find out the number of soil microorganisms, identification and enumeration of soil microbial species on the mineral and volcanic ash soil with different cropping system of the Jeju Island. The results obtained were summarized as follows: 1. The number of bacteria was high in mineral soil with rotation of upland crops than that of volcanic ash soil with continuous cropping system. 2. According to identification of soil bacteria, the most of bacteria were composed to short rod with Gram negative. Among the bacteria species, Rhizobium spp. and Flavobacterium spp. were most high population in both of mineral and volcanic ash soil. 3. The number of fungi in mineral soils were reduced by the rotated cultivation of upland crops but no significant differences were observed in volcanic ash soil with continuous cropping system. On the other hand, Aspergillus spp., Fusarium spp., and Penicillium spp. were most high population in both of mineral and volcanic ash soil. 4. Comparing of the number and species ot microorganism to the cash crops soil in main land, about 10 to 100 times for bacteria and more than two times for the number and species of fungi were lowered in Jeju Island soil.

• Restorative Dentistry and Endodontics
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• v.42 no.4
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• pp.316-323
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• 2017

Objectives: This study compared the amount of apically extruded bacteria during the glide-path preparation by using multi-file and single-file glide-path establishing nickel-titanium (NiTi) rotary systems. Materials and Methods: Sixty mandibular first molar teeth were used to prepare the test apparatus. They were decoronated, blocked into glass vials, sterilized in ethylene oxide gas, infected with a pure culture of Enterococcus faecalis, randomly assigned to 5 experimental groups, and then prepared using manual stainless-steel files (group KF) and glide-path establishing NiTi rotary files (group PF with PathFiles, group GF with G-Files, group PG with ProGlider, and group OG with One G). At the end of canal preparation, 0.01 mL NaCl solution was taken from the experimental vials. The suspension was plated on brain heart infusion agar and colonies of bacteria were counted, and the results were given as number of colony-forming units (CFU). Results: The manual instrumentation technique tested in group KF extruded the highest number of bacteria compared to the other 4 groups (p < 0.05). The 4 groups using rotary glide-path establishing instruments extruded similar amounts of bacteria. Conclusions: All glide-path establishment instrument systems tested caused a measurable apical extrusion of bacteria. The manual glide-path preparation showed the highest number of bacteria extruded compared to the other NiTi glide-path establishing instruments.

• The Journal of the Convergence on Culture Technology
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• v.8 no.6
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• pp.943-951
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• 2022

In this study, 8 kinds of fruits and vegetables such as apples, pears and radishes were cut and hot water extracts and Steamed hot water extract from fruits and vegetables were prepared and used as experimental substrates. As a result of fermenting with 1% (W/V) red ginseng extract (W/V) and 8 types of lactic acid bacteria mixed starter added to the lactic acid bacteria fermented extract, the pattern and content of ginsenosides were almost unchanged in the fruit and vegetable extract group and the steam treatment group. However, in the lactic acid bacteria fermented group, the TLC pattern was changed according to the fermentation process and treatment, and the content of ginsenosides converted into Rg₃(S) and Rg₅ increased. No change in the number of lactic acid bacteria (cfu) was observed in all four types of fruit and vegetable extracts. The number of lactic acid bacteria CFU was slightly decreased in the four fermented groups of fruit and vegetable extracts, but the growth inhibitory effect of beneficial bacteria was not significant. The growth inhibitory effect of the three harmful bacteria was not affected by the growth of E. coli and Pseudomonas in the four fruit and vegetable extracts. However, the proliferation of Salmonella was inhibited, which was confirmed as the growth inhibitory effect of the fruit and vegetable extract regardless of whether the steamed hot water extract or red ginseng extract was added.