• Korean Journal of Agricultural Science
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• v.44 no.4
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• pp.477-486
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• 2017

This review provides an overview of dietary nucleotides as an alternative to in-feed antibiotics for weaning pigs. Dietary nucleotides are composed of DNA or RNA molecules and are normally contained in protein-rich feed ingredient, brewer's yeast, yeast extract, and milk. Weaning pigs are suffering from several stresses, such as environmental challenges (i.e. crowding, transportation, and feeding). Such stressors can damage the intestinal epithelium and cause an invasion by Escherichia coli, secondary inflammatory responses, and post weaning diarrhea. To overcome weaning disorder, people often use antibiotics which reduce symptoms and boost growth performance. However, since antibiotics were banned due to concerns of antibiotic resistant bacteria, researchers are studying alternative materials to antibiotics. Dietary nucleotides are one of the alternative materials for replacing antibiotics and can be used in abnormal conditions, such as weaning diarrhea, low digestibility, and disease condition. Nucleotides have substances that have important roles in cell division and cell growth, affecting growth performance, intestinal condition, and immunological effect at the weaning stage. However, nucleotides' composition is very different between sources and this aspect makes it difficult to utilize nucleotides at the weaning stage. Therefore, this review paper focuses on i) the characteristics and functions of dietary nucleotides and ii) the effect of dietary nucleotides on the growth performance and immune system of pigs.

• Journal of Microbiology and Biotechnology
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• v.30 no.3
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• pp.404-416
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• 2020

Bacteria that are resistant to high temperatures and alkaline environments are essential for the biological repair of damaged concrete. Alkaliphilic and halotolerant Bacillus sp. AK13 was isolated from the rhizosphere of Miscanthus sacchariflorus. Unlike other tested Bacillus species, the AK13 strain grows at pH 13 and withstands 11% (w/v) NaCl. Growth of the AK13 strain at elevated pH without urea promoted calcium carbonate (CaCO₃) formation. Irregular vaterite-like CaCO₃ minerals that were tightly attached to cells were observed using field-emission scanning electron microscopy. Energy-dispersive X-ray spectrometry, confocal laser scanning microscopy, and X-ray diffraction analyses confirmed the presence of CaCO₃ around the cell. Isotope ration mass spectrometry analysis confirmed that the majority of CO₃^2- ions in the CaCO₃ were produced by cellular respiration rather than being derived from atmospheric carbon dioxide. The minerals produced from calcium acetate-added growth medium formed smaller crystals than those formed in calcium lactate-added medium. Strain AK13 appears to heal cracks on mortar specimens when applied as a pelletized spore powder. Alkaliphilic Bacillus sp. AK13 is a promising candidate for self-healing agents in concrete.

• Microbiology and Biotechnology Letters
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• v.17 no.4
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• pp.321-326
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• 1989

Eighty two bacterial strains have been isolated from five different soil and sewage samples by selective enrichment culture on m-toluate minimal medium. Two of these were identified as Pseudomonas capacia, one as P. putida, one as Yersinia intermedia, and one as Flavobaeterium odoratum. P. cepacia SUB37 appeared to carry plasmid superficially similar to TOL plasmid previously described in p. putida mt-2 and other two plasmids from Flavobacterium odorutum and Y. intermedia larger than that of p. putida mt-2. p. cepacia SUB37 was sensitive to streptomycin but resistant to rifampicin. P. cepacia SUB37 carrying plasmid metabolizes the hydrocarbons to benzoate and toluates via the corresponding alcohols and aldehydes. By the curing experiment, it appears that P. cepacia SUB37 carries TOL plasmid encoding for the enzymes responsible for the catabolism of toluene and xylene via benzoate and the toluates and then by meta pathway in the process of degradation of aromatic hydrocarbons. p. cepacia SUB37 degraded m-toluate rapidly to be very low level when it was fully grown.

• Food Science and Preservation
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• v.8 no.2
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• pp.206-212
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• 2001

Water extract of green tea(GTW) and 70% ethanol extract of green tea(GTE) were prepared for the test of antibacterial activity. The sensitivity of Staphylococcus aureus and Salmonella typhimurium to the green tea extracts in various pH of culture broth was tested. Tryptic soy broth(TSB) containing 0∼2%(w/v) of green tea extracts was adjusted to pH 5.0∼7.0 and inoculated with 10$\^$5/∼10$\^$6/ cells/ml of each bacteria. The plate counting method and clear zone test were used to determine inhibitory effect of green tea extracts. Green tea extracts completely inhibited the growth of S. aureus at 0.5% level and bactercidal at 0.5∼1.0% level of GTW and GTE at pH 5.0∼7.0. Green tea extracts were bactercidal to S. typhimurium at 1.5∼2.0% level of GTW and 1.0∼2.0% level of GTE at pH 7.0. Sal. typhimurium was more resistant than S. aureus. in same concentration of green tea extracts at same pH. The resistance of S. aureus and Sal. typhimurium was increased with decreasing pH of culture broth. The morphology of S. aureus cells treated with green tea extracts showed damage of cell wall and cytoplasmic membrane. Severely damaged cells of S. aureus lost electron dense material and cytoplasm. Green tea extracts stimulated autolysis and cell death of S. aureus. This result suggests that green tea extracts can be used as an effective natural antibacterial agent in food.

• Applied Biological Chemistry
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• v.10
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• pp.33-38
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• 1968

In order to determine proper conditions for the manufacture of canned Kimchi, a heat resistant lactic acid bacteria, the most acid producable strain, was isolated and identified as Lactabacillus plantarum. D-value for the isolate was calculated at 3 from a thermal death curve made at $60^{\circ}C$. The effects of acidity of Kimchi and the amount in a can, and the ratios of solid-liquid, were investigated. The most suitable time for sterilization with a type of can was determined as 25.2 minutes at $85^{\circ}C$. However in the period of heat treatment the quality was badly affected and this fact made desirable introducing of a adequate preservative additives into the manufacture of canned Kimchi.

• Journal of Korean Academy of Fundamentals of Nursing
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• v.13 no.3
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• pp.359-367
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• 2006

Purpose: This study was a within subject repeated pretest-posttest design done to compare the effect of disinfection and the degree of MRSA(Methicillin- resistant staphylococcus aureus) isolation from hand disinfectant in ICU nurses. Method: Out of the total internal medicine/surgery ICU nurses at a university hospital in Seoul, 29 female nurses who were participating in direct patient care were participants in this study. After collection of samples, Staphylococcus aureus and MRSA were isolated from the palms, nails and nasal cavities of the nurses according to disinfectants (soap and beta-scrub). Results: The effect of disinfection was greater in the beta-scrub group than in the soap group, and the effect of disinfection on palms was higher in the beta-scrub group than in the soap group. As for the degree of MRSA isolation, there was more isolation in palms in the soap group than in the beta-scrub group but there was no difference in the degree of MRSA isolation from the hand disinfectant in nails and nasal cavities. Conclusion: Beta-scrub showed a superior prolonged effect against transient bacteria compared with soap. Further, to reduce MRSA infection, we recommend interventions focused on these aspects.

• International Journal of Oral Biology
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• v.31 no.1
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• pp.7-10
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• 2006

Mitis-salivarius sucrose bacitracin(MSB) medium is widely used in the selective isolation of mutans streptococci(MS), a designation for a group of oral cariogenic species. Recently, we have isolated three bacterial strains grown on MSB agar from human dental plaques. The three strains exhibited biochemical characteristics similar to those of the biotype IV of MS, with the exception that they manifested a positive reaction for arginine deaminase. The objective of this study was to identify and characterize these three clinical isolates. The bacteria were identified with biochemical tests as well as by 16S rDNA cloning and sequencing. In order to compare the antibiotics susceptibility of the clinical isolates with that of type strain, the minimum inhibitory concentrations of 9 antibiotics were determined using broth dilution assays. The results identified all of our three clinical isolates as Enterococcus faecalis. All E. faecalis strains were found to be susceptible to penicillin G, amoxicillin, augmentin, and vancomycin, but were resistant to ciprofloxacin, cefuroxim axetil, and clindamycin. Our findings indicate that E. faecalis is capable of growing on MSB agar, and suggest that the MSB medium be improved so that only MS should be recoverable on the medium, as originally devised for their selection.

• Journal of Environmental Health Sciences
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• v.27 no.1
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• pp.75-82
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• 2001

Microorganisms can attach firmly to food contact surface material and the resitance of adherent bacteria differ markedly from planktonic cells. Therefore, adherent cells are a potential contamination problem to the food preparation because of their high resistance. to sanitation and heat treatment. This study was carried out in order to investigate growth and decontamination of Listeria monocytogenes attached to stainless steel, glass and plastic. Listeria monocytogenes cells could attach to all types of surface at three temperatures after contact times for 24 hrs. The numbers of adherent cells were greater at higher temperatures, but not increased with incubation time. When recovery of adherent cells was investigated, after 24 grs, the numbers of adherent cells were about 10$^{7}$ , 10$^{10}$ , 11$^{11}$ at 4$^{\circ}C$, $25^{\circ}C$, 3$0^{\circ}C$ repectively. Planctonic cells decreased by 2 log cycles after exposure to the domestic sanitizer. Adherent cells showed high resistance to domestic sanitizers and that was dependent upon surface materials studied, being greatest on plastic followed by stainless steel and glass. Adherent cells were more resistant to heat treatment than planktonic cells. When adherent cells were exposed to the temperature of 5$0^{\circ}C$, 55$^{\circ}C$, 57.5$^{\circ}C$ for 10 min, their populations did not decrease significantly. When the temprature increased to 6$0^{\circ}C$, cells attached to all types of surfaces were completely inactivated for 10 min.

• Korean Journal of Food Science and Technology
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• v.49 no.2
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• pp.146-150
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• 2017

Staphylococcus aureus is a pathogenic bacterium that causes food poisoning, exhibits a strong capacity to form biofilm, and is highly resistant to antimicrobial agents. The purpose of this study was to investigate the antimicrobial characteristics of corosolic acid against S. aureus. S. aureus showed high susceptibility to corosolic acid in a concentration-dependent manner. The minimum inhibitory concentration and colony-forming ability determined by the broth microdilution method showed that corosolic acid had strong antimicrobial activity against the bacteria. The diameters of the inhibition zone and numbers of colony forming units at each concentration of corosolic acid were also measured. In addition, corosolic acid displayed potent biofilm inhibition activity against S. aureus at concentrations below its minimum inhibitory concentration. These results suggest that corosolic acid can be used to effectively prevent biofilm formation by S. aureus, thereby making S. aureus more susceptible to the action of antimicrobials.

• Archives of Plastic Surgery
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• v.36 no.3
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• pp.277-282
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• 2009

Purpose: The vegetative state is a clinical condition with complete unawareness of self and environment, but with preservation of brain - stem functions. Vegetative patients may have nosocomial infections in their wounds, like pressure sores and infected craniums after cranioplasties. Usually flap surgery is necessary for those wounds, but decision of undergoing surgery is difficult because of various adverse conditions of vegetative patients. We share our experience of several successful flap surgeries in vegetative patients, and evaluate obstacles and requirements to get satisfactory results. Methods: From December 2005 to September 2008, a total of 4 vegetative patients underwent surgeries. In 2 patients with infected artificial craniums, scalp reconstructions with free flaps were performed. In other 2 patients with huge pressure sores with sepsis, island flap coverage of wounds was done. Retrospective study was done on hospital day, vegetative period, number of surgeries done, underlying diseases, causative bacteria, and contents of informed consent. Results: Mean hospital day was 14 months and mean vegetative period was 17.5 months. Patients underwent average of 4.5 surgeries under general anesthesia. There were several underlying diseases like hypertension, DM, CHF and chronic anemia. MRSA(Methicilin - resistant Staphylococcus Aureus) was cultured from every patient's wounds. Informed consent included a warning for high mortality and a need of attentive familial cooperation. Conclusion: There are three requirements for doing flap surgeries in vegetative patients. First, to prevent aggravation of brain damage and underlying diseases by general anesthesia, multidisciplinary team approach is needed. Second, operation should be beneficial for prolonging patient's lifespan. Third, because postoperative care is very difficult and long hospitalization is needed, detailed informed consent and highly cooperative attitude of family should be confirmed before operation.