• KSBB Journal
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• v.29 no.6
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• pp.443-447
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• 2014

Biosynthesis of lactate-containing polyhydroxyalkanoates (PHAs) was examined in recombinant Escherichia coli W strain from sucrose. The Pseudomonas sp. MBEL 6-19 phaC1437 gene and the Clostridium propionicum pct540 gene, which encode engineered Pseudomonas sp. MBEL 6-19 PHA synthase 1 ($PhaC1_{Ps6-19}$) and engineered C. propionicum propionyl-CoA transferase ($Pct_{Cp}$), respectively, were expressed in E. coli W to construct key metabolic pathway to produce poly(3-hydroxybutyrate-co-lactate) [P(3HB-co-LA)]. The recombinant E. coli W expressing the phaC1437 gene and the pct540 gene could synthesize P(3HB-co-13mol%LA) up to the polymer content of 31.3 wt% when it was cultured in chemically defined MR medium containing 20 g/L of sucrose and 2 g/L of sodium 3-hydroxybutyrate. When Ralstonia eutropha phaAB genes were additionally expressed to provide 3-hydroxybutyrate-CoA (3HB-CoA) from sucrose, P(3HB-co-16mol%LA) could be synthesized from sucrose as a sole carbon source without supplement of sodium 3-hydroxybutyrate in culture medium, but the PHA content was decreased to 12.2 wt%. The molecular weight of P(3HB-co-16 mol%LA) synthesized in E. coli W using sucrose as carbon source were $1.53{\times}10^4$ ($M_n$) and $2.78{\times}10^4$ ($M_w$), respectively, which are not different from those that have previously been reported by other recombinant E. coli strains. Engineered E. coli strains developed in this study should be useful for the production of lactate-containing PHAs from sucrose, one of the most abundant and least expensive carbon sources.

• Korean Journal of Agricultural Science
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• v.46 no.4
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• pp.981-989
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• 2019

Coffee is a popular beverage worldwide, and the scale of consumption is growing rapidly. Many studies have shown that increased coffee consumption has various effects on human health, including beneficial effects on liver diseases, clinical type 2 diabetes, and Parkinson's disease. However, the influences of coffee or caffeine (a component of coffee) on the gut microbiota have not been examined in detail. Here, we tested whether caffeine could alter the antimicrobial activity of L. casei against E. coli. Interestingly, we found that treatment with 0.3 mg/mL caffeine increased the antimicrobial activity of L. casei against E. coli. This activity was not associated with the release of lactic acid but did appear to be related to a heat-labile factor present in the L. casei culture supernatant. Our analyses suggest that the putative antimicrobial factor found in the culture supernatant of L. casei treated with caffeine may be bacteriocin. Taken together, our results suggest that caffeine, which is an ingredient of coffee, increases the antimicrobial activity of L. casei against E. coli through the enhanced production of bacteriocin. These findings also suggest that coffee consumption affects the ability of beneficial bacteria to decrease pathogenic bacteria and/or prevent the progression of bacterial infection-associated diseases in the gut.

• 한국생물공학회:학술대회논문집
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• 2005.04a
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• pp.196-196
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• 2005

• Journal of the Korean Society of Food Culture
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• v.15 no.1
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• pp.9-15
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• 2000

This study was conducted to investigate the antimicrobial activity of grapefruit extracts and polylysine mixture against food-borne pathogens. The mixture was showed a potent and quick antibacterial activity for 5 major bacteria causing food poisoning i.e. Escherichia coli, Escherichia coli O-157, Salmonella typhi, Staphylococcus aureus, Vibrio cholerae. The antibacterial effect of the mixture on the ordinary bacteria inhibiting on the surface of lettuce was lasted even 6 hrs after the treatment, however the mixture was non-effective on the color, smell and taste of lettuce. The treatment with 10% mixture solution of the foods such as fish, meat, rice and bread suppressed the growth of the bacteria and kept the foods more freshly than the untreated foods.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.33 no.1
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• pp.32-37
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• 2000

Silver-alginate (Ag-alginate) was prepared with Na-alginate extracted from marine brown algae. The antibacterial effect of Ag-alginate against Staphylococcus aureus and Escherichia coli was carried out by measuring optical density of liquid culture at 600 nm. The cell growth of S. aureus and E. coli was very active at pH 7, and was inhibited by adding Ag-alginate with more than $0.006 wt.{\%}$ of stiver content. The cell growth of S. aureus .and E. coli was also influenced by the characteristics of counter Jon of silver. The cell growth of S. aureus was less inhibitory than E. coli at the same concentration of Ag-a1ginate.

• Journal of Environmental Health Sciences
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• v.21 no.2
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• pp.54-67
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• 1995

The biosynthesis of galactolipid and galactose and their composition of fatty acid in E. coli and B. subtilis treated ] with copper chloride (10 ppm), nickel chloride (50 ppm), manganese chloride (100 ppm) during the culture were analyzed. The contents of MGDG, DGDG and total lipids in treatment with metal compounds were lower to compared with the control. In E. coli, the major fatty acid unitized for biosyntheis of MGDG were palimitic acid (ave. 36.87%) and linolenic acid (ave. 14.79%) in control. In MGDG, the major fatty acids were utilized for palmitic acid (ave. 20.00%) and myristic acid (ave. 7.32%) in treatment with copper chloride, lauric acid (ave. 11.71%) and linolenic acid (ave. 11.06%) in manganese chloride treatment. And in nickel chloride treatment, it was palmitic acid (ave. 36.16%) and oleic acid (ave. 6.43%) were use in MGDG formation. In DGDG, in copper chloride treatment, it was lauric acid (ave. 19.41%) and oleic acid (ave. 9.95%) in biosynthesis of galactolipid. and in treatment with nickel chloride linolenic acid (ave. 15.39%) and linoleic acid (ave. 13.51%), in manganese chloride treatment palmitic acid (ave. 29.76%) and palmitoleic acid (ave. 11.35%) were used in DGDG formation. In B. subtilis, the major fatty acids utilized for biosynthesis of galactolipid was palmitic acid (ave. 30.86%) and linolenic acid (ave. 8.36%) in control. Otherwise, in MGDG, the major fatty acids were utilized for palmitic acid (ave. 28.92%) and stearic acid (ave. 13.25%) in treatment with copper chloride, and palmitic acid (ave. 15.73%) and lauric acid (ave. 11.88%) in manganese chloride treatment. It was continned that nickel chloride treatment was palmitic acid (ave. 35.16%) and palmitoleic acid (ave. 12.47%). The major fatty acids in DGDG were utilized for palmitic acid(ave. 34.19%) and linoleic acid (ave. 17.45%) in copper chloride treatment, and lauric acid (ave. 11.16%) and myrisitic acid (ave. 8.65%) in manganese chloride treatment. In treatment with nickel chloride, it was palmitoleic acid (ave. 10.30%) and myristic acid (ave. 7.81%) were used galactolipid formation.

• KSBB Journal
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• v.13 no.1
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• pp.96-100
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• 1998

Two promoters (trc and P$\rho$) were inserted in PHA operon derived from Alcaligenes eutrophus to obtain high chain molecules of polyhydroxybutyrate (PHB) in recombinant Escherichia coli. Newly designed PHA operon was used to control the gene expressions of hydroxybutyric CoA and PHA polymerization, separately. Plasmids containing new synthetic operon was transformed into E. coli DH5$\alpha$ and analyzed for PHB production. Without induction of the PHA biosynthetic operon, PHA synthase which has low activity might supply low concentration of initiator during the polymerization reaction, resulting very high molecular weight of polymer. An increase of PHB average molecular weight was observed with decreased IPTG (isopropyl $\beta$ -Dithiogalactosidase) concentration. When no IPTG was added to the culture of E. coli DH5$\alpha$ /$\rho$ SJS1 which contained two promoters in PHA operon, high chain polymer having an average molecular weight of $2.5{\times}10^7$ was achieved. Analysis of the enzyme activities of PHA biosynthetic enzymes suggests that PHA synthase, the enzyme responsible for polymerizing 3-hydroxybutyric CoA, controls the molecular weight of PHB produced in vivo.

• Biotechnology and Bioprocess Engineering:BBE
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• v.10 no.4
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• pp.378-384
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• 2005

Vanillin is one of the world's principal flavoring compounds, and is used extensively in the food industry. The potential vanillin production of the bacteria was compared to select and clone genes which were appropriate for highly productive vanillin production by E. coli. The fcs (feruloyl-CoA synthetase) and ech (enoyl-CoA hydratase/aldolase) genes cloned from Amycolatopsis sp. strain HR104 and Delftia acidovorans were introduced to pBAD24 vector with $P_{BAD}$ promoter and were named pDAHEF and pDDAEF, respectively. We observed 160 mg/L vanillin production with E. coli harboring pDAHEF, whereas 10 mg/L of vanillin was observed with pDAHEF. Vanillin production was optimized with E. coli harboring pDAHEF. Induction of the fcs and ech genes from pDAHEF was optimized with the addition of 13.3 mM arabinose at 18 h of culture, from which 450 mg/L of vanillin was produced. The feeding time and concentration of ferulic acid were also optimized by the supplementation of $0.2\%$ ferulic acid at 18 h of culture, from which 500 mg/L of vanillin was obtained. Under the above optimized condition of arabinose induction and ferulic acid supplementation, vanillin production was carried out with four different types of media, M9, LB, 2YT, and TB. The highest vanillin production, 580 mg/L, was obtained with LB medium, a 3.6 fold increase in comparison to the 160 mg/L obtained before the optimization of vanillin production.

• Korean Journal of Veterinary Service
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• v.17 no.1
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• pp.61-66
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• 1994

Microbiological culture was conducted in the meat surface of cattles and pigs that was slaughtered in the Chung -Ju area and the result are as follows : 1. The number of bacteria in antemortem meat surface was higher ten times in March and ten to one thousand times in June to August compared with postmortem meat surface. 2. Microbes isolated in the meat surface, at the time of slaughter, was Stahylococcus spp., E. coli, Fungus and Streptococcus spp. 3. Bacteria was isolated in every parts of meat surface regardless to their location and many Fungus was isolated during summer.

• Journal of Microbiology
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• v.45 no.6
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• pp.558-565
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• 2007

Using microarray analysis, we determined those Salmonella genes induced at the entry of stationary phase, and subsequently discovered that uncharacterized yliH was induced most dramatically. We set out to establish the molecular mechanism underlying the stationary phase induction of yliH under the standard culture condition, LB with vigorous aeration, by analyzing its promoter activity in various mutant backgrounds, lacking stationary phase ${\sigma}$, $RpoS^-$, or stringent signal molecules ppGpp, ${\Delta}relA$ ${\Delta}spoT$. It was found that the stationary phase induction of yliHp was partially dependent on rpoS but entirely dependent on ppGpp. DNA sequence analysis revealed that the Salmonella yliH gene is composed of 381 base-pair nucleotides, with overall amino acid sequence revealing 76.38% amino acid identity and 88.98% similarity with Escherichia coli yliH, although no motif from data base was noted for its possible role. Recently however, it has been reported that yliH in E. coli was implicated in biofilm formation and motility by repressing these activities (Domka et al., 2006). We have constructed a mutant Salmonella deleting yliH gene by allele replacement and examined its phenotype, and found that the yliH in Salmonella more or less affects motility and adherence by enhancing these activities. The effect on biofilm formation in Salmonella was uncertain. Moreover, addition of cloned yliH of E. coli into Salmonella did not reduce motility or adherence. Taken together, it appears that the pathways implicating yliH for biofilm formation and motility in E. coli and in Salmonella are somewhat different.