• Microbiology and Biotechnology Letters
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• v.31 no.1
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• pp.90-93
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• 2003

The antibacterial activity of chitosan-alginate-Fe(II) complex (CAFC) against Escherichia coli and Staphylococcus aureus, and an opportunistic pathogen, Candida albicans, was investigated. A concentration of 1 mg/1 was needed to inhibit the growth of S. aureus and E. coli, while 100 mg/liter was sufficient for the growth inhibition of Candida albicans. The ion leakage of potassium and phosphate from E. coli cell and the penetration of ethidium bromide dye into it indicate that CAFC might be able to increase the cell permeability and consequently cellular leakage, thus leading to cell plasmolysis. Scanning electronmicroscope showed that E. coli cells treated with CAFC became irregular, swelling and expanded. In a field trial, control piglets showed average mortality of up to 60% within 3 days after the onset of diarrhea. In contrast, CAFC-treated groups without mortality was decreased to average 56% on the 1 st day after the treatment, and average 7% on the 3rd day. After then, piglets with diarrhea was not found.

• Biotechnology and Bioprocess Engineering:BBE
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• v.11 no.2
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• pp.164-167
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• 2006

The influence of temperature and agitation on the growth of Escherichia coli expressing hepatitis B core antigen (HBcAg) in stirred tank bioreactor were investigated. The highest specific growth rate for E. coli$(0.844 h^{-1})$ was achieved at a temperature of $37^{\circ}C$ and an agitation speed of 250 rpm. The activation energy for the growth of the E. coli strain W3110lQ in the stirred tank bioreactor was estimated to be 11 kcal/mol. The highest protein yield was achieved at a temperature of $44^{\circ}C$ and an agitation speed of 250 rpm. The relative protein concentration at $44^{\circ}C$ is 30 and 6% higher compared to that at 30 and $37^{\circ}C$, respectively.

• YAKHAK HOEJI
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• v.60 no.1
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• pp.1-7
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• 2016

The aim of this study was to investigate the prevalence of quinolone resistant E. coli from retail meat and to characterize the resistant determinants. Determination of minimum inhibitory concentration, the sequence analysis of gyrA, gyrB, parC, and parE quinolone resistance determining regions (QRDR), the presences of plasmid mediated quinolone resistance (PMQR) and the expression of efflux pump genes were investigated. Of the total 277 retail meat samples, 67 coli form bacteria were isolated. 15 of 67 isolates showed nalidixic acid resistance and 7 of 15 nalidixic acid resistant isolates were also resistant to ciprofloxacin, moxifloxacin and levofloxacin. 11 of 15 nalidixic acid resistant strains were isolated from chicken, 2 of 15 were isolated from beef and 2 of 15 were isolated from pork samples. 11 of 15 nalidixic acid resistant strains have single mutation at codon 87 (D87N or D87G) in gyrA, 2 of 11 gyrA mutants have double mutations at codon 86 and 87 (L86A and L87I) in parC with mutations at codon 434+445+465 or 429 in gyrB. 2 of 15 resistant isolates harbored qnrS, a PMQR determinant. Over expression of the acrB gene, efflux pump gene (3.93~16.53 fold), was observed in 10 of 15 resistant isolates.

• Asian-Australasian Journal of Animal Sciences
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• v.25 no.8
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• pp.1178-1183
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• 2012

A 5-wk trial with 96 ($(Landrace{\times}Yorkshire){\times}Duroc$) pigs ($BW=26.56{\pm}0.42kg$) was conducted to investigate the effect of eugenol and cinnamaldehyde as feed additive in growing pigs. Pigs were assigned to 1 of 3 treatments in a randomized complete block design according to their sex and BW. Each treatment contained 8 replications with 4 pigs (2 gilts and 2 barrows) per pen. Treatments included: control (basal diet; CON); (basal diet+1,000 mg eugenol/kg; ET); (basal diet+1,000 mg cinnamaldehyde/kg; CT). Administration of eugenol and cinnamaldehyde did not did not affect (p>0.05) the growth performance and apparent total tract digestibility. Dietary CT and ET led to a higher (p<0.05) lymphocyte concentration compared with CON. The inclusion of CT and ET decreased (p<0.05) the fecal E. coli concentration (p>0.05). Pigs fed the diets supplemented with eugenol and cinnamaldehyde had reduced (p<0.05) $NH_3$ and $H_2S$ concentration throughout the experiment. In conclusion, results obtained in the present study indicated that supplementation of eugenol and cinamaldehyde had no effect on growth performance of pigs but exhibited lymphocyte-enhancing activity and decreased the fecal E. coli concentration and fecal noxious gas content ($NH_3$ and $H_2S$).

• YAKHAK HOEJI
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• v.40 no.3
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• pp.347-350
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• 1996

The post-antibiotic effect (PAE), which is defined as the period of time lag that the target organisms resume normal growth rate after complete removal of the antibiotics, of LB 20304 and ciprofloxacin was evaluated against Staphylococcus aureus 6538p and Escherichia coli 3190Y, respectively. The PAE was estimated by adding each antibiotic to a log phase of growth and incubating at $37^{\circ}$C for 1 h.Antibiotic was removed by centrifugation, and total viable cell counts were determined hourly for a further 10 h. The PAEs of LB20304 against S. aureus at concentrations of $1{\times}MIC\;and\;2{\mu}g/ml$ were 10 min and 93min, respectively. LB20304 showed a comparable PAE to ciprofloxacin. Against E. coli, the PAE of LB20304 was also similar to that of ciprofloxacin at concentration of $4{\times}MIC$ but it was much longer than that of ciprofloxacin at concentration of 2${\mu}g/ml$. LB20304 showed higher lethality than ciprofloxacin against both S. aureus and E. coli strains.

• Korean journal of food and cookery science
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• v.27 no.4
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• pp.17-26
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• 2011

This study was performed to analyze the antibacterial activity against food hazardous microorganisms and antimutagenic effects of Sanguisorba officinalis L. ethanol extracts on Salmonella Typhimurium TA100. The antibacterial activity was evaluated by paper disc diffusion assay, minimum inhibition concentration (MIC), and optical density of the culture with the ethanol extract for 24 hr. Antibacterial activity was tested with seven microorganisms including Escherichia coli, Escherichia coli O157:H7, Pseudomonas aeruginosa, Salmonella Typhimurium, Listeria monocytogenes, Bacillus cereus, and Staphylococcus aureus. The paper disc diffusion assay showed distinct clear inhibition zones around the discs treated with the extract for five microorganisms, except Escherichia coli and Escherichia coli O157:H7. MIC values were 0.625-2.5 mg/mL for these five strains that showed clear zones. The time-kill assay was consistent with the results from the paper disc diffusion assay and MIC test. Additionally, antimutagenicity of the extract was determined using the Ames test. The ethanol extract at 5 mg/plate inhibited 72.42% and 89.85% of mutagenicity induced by 4-nitroquinoline 1-oxide and sodium azide, respectively. These results demonstrate that the ethanol extract from S. officinalis L. has remarkable antibacterial activity and antimutagenicity.

• The Korean Journal of Food And Nutrition
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• v.18 no.1
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• pp.81-87
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• 2005

This study was performed to investigate the antimicrobial activities of the Plagiorhegama dubium extracts against food-borne pathogens. The methanol extract was partitioned into petroleum ether, chloroform, ethyl acetate, and methanol portions. The antimicrobial activity of the P. dubium extracts was determined using a paper disc method against food-borne pathogens and food spoilage bacteria. The methanol extracts of P. dubium showed the highest antimicrobial activity against Staphylococcus aureus and Escherichia coli. The synergistic effect has been found in combined extracts of P. dubium and Hedyotis diffsa as compared to each extracts alone. Finally, the growth inhibition curve was determined using methanol extracts of P. dubium against S. aureus and E. coli. The methanol extract of P. dubium showed strong antimicrobial activity against S. aureus at the concentration of 4,000 ppm. The 4,000 ppm of ethyl acetate portion from P. dubium retarded the growth of S. aureus more than 36 hours and E. coli up to 60 hours. The methanol extracts of P. dubium has been shown the antimicrobial activity against S. aureus and E. coli.

• Korean Journal of Food Science and Technology
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• v.47 no.4
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• pp.446-451
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• 2015

The market for green vegetable juice (GVJ) is growing owing to the increasing demand for healthy food; however data on the safety and quality of GVJ are poorly reported. The objective of this study was to investigate the change in microbial community in GVJ during storage and its contamination by E. coli O157:H7. The microbial community was analyzed via culturable and non-culturable methods at 5, 10, and $25^{\circ}C$ for different storage times. In the non-culturable method, denaturing gradient gel electrophoresis (DGGE) was used. The initial bacterial concentration was $2.92{\times}10^5CFU/mL$, which exceeded the limit prescribed by the Korean Food Hygiene law. The results of the DGGE analysis indicated that the microbial community during storage was diverse and the spoilage lactic acid bacteria were prevalent at a later stage. Other bacteria such as Rahnella, Citrobacter, Pseudomonas, and Cyanobacteria were identified. Thus, the results strongly emphasize the need to pay attention to GVJ production safety, especially with respect to temperature control, in order to prevent the growth of foodborne pathogens such as E. coli O157:H7 and other spoilage bacteria.

• Korean Journal of Pharmacognosy
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• v.43 no.4
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• pp.323-327
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• 2012

Acne, also known as Acne vulgaris, is a common disorder of human skin involving the sebaceous gland and Propionibacterium acnes (P. acnes). The purpose of this study was to demonstrate whether anti-acne herbal complex (AAHC), a functional extract from herbal complex can be used for acne treatment as a natural product. We first demonstrated anti-acne activity of AAHC in mouse acne model. Acne was induced by injecting P. acnes on the backside $2{\times}10^7$ CFUs in ICR mice and then the mice were treated with AAHC by dermal application once daily. ACFREE$^{(R)}$ (clindamicin phosphate) was used as a positive control. Treatment with AAHC decreased the P. acnes-induced skin swelling and inflammation. AAHC treatment significantly decreased serum DHT concentration in acne-induced mice. Especially, treatment of 20% AACH in mice was more effected than 40%. We next evaluated the antimicrobial property of AAHC against P. acnes, Staphylcococcus aureus (S.aureus), and Escherichia coli (E. coli). Incubation of P. acnes, S. aureus, and E. coli with AAHC showed minimal inhibitory concentration (MIC) values against the bacterial growth lower. Alamar blue method was also carried for the antibacterial activity. It was effectively MIC level at 6.25% of P. acnes. AAHC effectively inhibited the growth of S. aureus and E. coli at 0.097% on MIC level, respectively. Our results showed the potential of using AAHC as an alternative treatment for antibiotic therapy of acne and the application of AAHC as a herbal medicine for acne treatment.

• BMB Reports
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• v.28 no.1
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• pp.21-26
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• 1995

The Escherichia coli mixed-function serC-aroA operon encodes biosynthethic enzymes for unrelated pathways leading to the syntheses of serine and aromatic amino acids. It has been proposed that the operon is expressed in a cAMP-dependent manner. In this work experiments were performed to investigate the cAMP-dependent expression of the operon. Exogenous cAMP increased ${\beta}$-galactosidase synthesis in the $cya^+$ and cya strains harboring the serC-aroA-lac fusion plasmid. This enhancement was more dramatic in the $cya^-$ strain grown in a minimal medium. In a dot blot assay the serC-aroA mRNA content increased in a concentration-dependent pattern after the addition of exogenous cAMP. The activity of phosphoserine aminotransferase, encoded by the serC gene, apparently increased in E. coli cells after the addition of cAMP. All results obtained confirmed that the expression of the E. coli serC-aroA operon is positively regulated by cAMP at the level of transcription.