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Jin, Q.,Li, L.,Moon, J.S.,Cho, S.K.,Kim, Y.J.,Lee, S.J.,Han, N.S. Society for Bioscience and Bioengineering, Japan ; 2016 Journal of bioscience and bioengineering Vol.121 No.5
<P>The n-form of lactate, which causes metabolic stress upon excessive dietary intake, is mainly produced by Leuconostoc sp., the predominant species in sauerkraut. To shift the metabolic flux of D-lactate from pyruvate to L-lactate, we expressed the L-lactate dehydrogenase (ldhL) gene in Leuconostoc mesenteroides ATCC 8293. The IdhL gene from Lactobacillus plantarum was introduced into L. mesenteroides using the shuttle vectors pLeuCM and pLeuCM42. To elevate the expression level of IdhL in L. mesenteroides, the nucleotides for pyruvate kinase promoter were fused to IdhL and cloned into above vectors to construct pLC18pkL and pLC42pkL. As results, introduction of pLC42pkL in L. mesenteroides significantly improved both L-LDH activity and L-lactate productivity during fermentation, decreasing the D-/L-lactate ratio. When used as a starter culture for sauerkraut fermentation, recombinant L. mesenteroides harboring pLC42pkL increased L-lactate concentration and decreased D-lactate concentration compared to the wild type strain. We newly developed a recombinant L. mesenteroides which has high L-lactate dehydrogenase activity and applied this strain to minimize the harmful effect of D-lactate during the sauerkraut fermentation. To the best of our knowledge, we demonstrate for the first time the effective use of recombinant Leuconostoc sp. for quality improvement of fermented foods. (C) 2015, The Society for Biotechnology, Japan. All rights reserved.</P>
Interaction of copper(II) with N-substituted bis(2-pyridylmethyl)amine derivatives
Kim, M.,Mora, C.,Lee, Y.H.,Clegg, J.K.,Lindoy, L.F.,Min, K.S.,Thuery, P.,Kim, Y. Elsevier 2010 Inorganic chemistry communications Vol.13 No.10
<P>Interaction of copper(II) with the N-substituted bis(2-pyridylmethyl)amine derivatives, (R)-N-1,N-1-bis (pyridine-2-ylmethyl)butane-1,2-diamine (L-1) and (R)-2-(bis(pyridin-2-ylmethyl)amino)butan-1-ol (L-2), has led to isolation of optically active [Cu(L-1)Cl]PF6 (1) and [Cu(L-2)Cl]ClO4 (2), respectively. The X-ray structures of (1) and (2) show that the copper is bound to all four heteroatoms of the respective ligands as well as to a chlorine atom in a distorted square pyramidal arrangement in which the three nitrogens of L-1 or L-2 occupy three positions of each basal plane while the fourth position is occupied by the chloro ligand; apical sites in each case are filled by the amine donor from the NH2-substituted butane arm in L-1 or the (protonated) alcohol oxygen of the 2-aminobutane-1-ol substituent in L-2. To a first approximation the coordination geometry in 2 is distorted square pyramidal; however, the remaining (axial) site on each copper centre is involved in a long contact (2.96 angstrom) with a bound chloro ligand from an adjacent complex which connects individual complex units in a zigzag 1-D polymeric chain, so that the coordination geometry could also be seen as pseudo-octahedral. A temperature-dependent magnetic study revealed the presence of ferromagnetic exchange coupling between copper centres in the chain reflecting the orthogonal structure between the chloro-bridged copper(II) ions; in contrast, and as expected, the discrete complex 1 is magnetically dilute. (C) 2010 Elsevier B.V. All rights reserved.</P>
Han, J.,Park, S.J.,Thu, V.T.,Lee, S.R.,Long, L.T.,Kim, H.K.,Kim, N.,Park, S.W.,Jeon, E.S.,Kim, E.J.,Yoon, C.H.,Cho, G.Y.,Choi, D.J. Elsevier/North-Holland Biomedical Press 2013 INTERNATIONAL JOURNAL OF CARDIOLOGY Vol.168 No.3
Background: The aim of this study was to investigate the cardioprotective effect of fimasartan, a newly developed angiotensin II receptor type I blocker (ARB), against myocardial ischemia/reperfusion (I/R) injury and to identify the mechanism by which it reduces mitochondrial damage. Methods: Fimasartan was administered intravenously to Sprague-Dawley rats (3mg/kg), cardiomyocytes (50μM), and H9c2 cells (50μM) before ischemia or hypoxia. Myocardial infarction (MI), echocardiograms, DNA fragmentation, terminal deoxynucleotidyl transferase-mediated dUTP in situ nick-end labeling, immunoblotting, oxygen consumption, confocal microscopic appearance, and L-type Ca<SUP>2+</SUP> current (I<SUB>Ca,L</SUB>) were then assessed. Results: Fimasartan pretreatment remarkably reduced the rate of MI and improved cardiac performance well after I/R (n=9/group). Fimasartan also reduced apoptotic cell death both in vivo and in hypoxia/reoxygenation (H/R)-treated H9c2 cells (n=5~8/group). H/R-induced mitochondrial O<SUB>2</SUB><SUP>-</SUP> production and collapse of membrane potential were markedly attenuated in fimasartan-treated cardiomyocytes (n=4~6/group). Additionally, mitochondrial Ca<SUP>2+</SUP> overload during reoxygenation was suppressed by fimasartan (n=4~6/group), and this was found to be possibly related to the inhibition of I<SUB>Ca,L</SUB> and mitochondrial Ca<SUP>2+</SUP> uniporter. Furthermore, fimasartan pretreatment increased phosphorylations of Akt and glycogen synthase kinase-3β (n=5~7/group), decreased pro-apoptotic p53 levels, and increased anti-apoptotic Bcl-2 levels (n=4) during reperfusion. Conclusions: Fimasartan preconditioning has the potential to modulate Bcl-2 and suppress I/R-induced Ca<SUP>2+</SUP> overload by inhibiting I<SUB>Ca,L</SUB> and MCU. These beneficial effects could prevent the mitochondrial dysfunction and apoptosis accompanied by I/R.
Elimination of the cryptic plasmid in Leuconostoc citreum by CRISPR/Cas9 system
Jang, Y.J.,Seo, S.O.,Kim, S.A.,Li, L.,Kim, T.J.,Kim, S.C.,Jin, Y.S.,Han, N.S. Elsevier Science Publishers 2017 Journal of biotechnology Vol.251 No.-
<P>Leuconostoc spp. are important lactic acid bacteria for the fermentation of foods. In particular, L. citreum strains isolated from various foods have been used as host strains for genetic and metabolic engineering studies. In order to develop a food-grade genetic engineering system, L. citreum CB2567 was isolated from Kimchi. However, the isolated bacterium contained a cryptic plasmid which was difficult to eliminate. As the existence of the plasmid might hinder strain engineering, we eliminated the plasmid using an RNA-guided DNA endonuclease CRISPR/Cas9 system. We demonstrated that a plasmid-free L. citreum CB2567 host strain could be efficiently constructed through a two-step procedure: 1) transformation of the 'killer' plasmid expressing Cas9 endonuclease and a guide RNA (gRNA) targeting for a specific sequence in the cryptic plasmid, and 2) serial subculture without antibiotics for curing the killer plasmid. When the crude extract of L. citreum expressing Cas9 and the guide RNA was incubated with a PCR fragment containing the specific sequence recognized by the guide RNA, the PCR fragment was cleaved. Also, the cryptic plasmid pCB42 was successfully eliminated from the host strain after transforming the plasmid harboring Cas9 and the guide RNA. The Cas9 and gRNA expression plasmid used in this study can be applied for genome engineering purposes by additionally introducing an editing DNA template to repair the double strand DNA breakage caused by Cas9 in the genome of L. citreum. This study demonstrates the feasibility of developing CRISPR/Cas9-based genetic engineering tools to develop a safe host strain and construct food-grade lactic acid bacteria without residual antibiotic markers.</P>
Seo, H.S.,Beuchat, L.R.,Kim, H.,Ryu, J.H. Elsevier Science Publishers 2015 International journal of food microbiology Vol.215 No.-
There is a growing interest in the use of naturally-occurring antimicrobial agents such as plant essential oils (EOs) to inhibit the growth of hazardous and spoilage microorganisms in foods. Gaseous EOs (EO gases) have many potential applications in the food industry, including use as antimicrobial agents in food packaging materials and sanitizing agents for foods and food-contact surfaces, and in food processing environments. Despite the potentially beneficial applications of EO gases, there is no standard method to evaluate their antimicrobial activities. Thus, the present study was aimed at developing an experimental apparatus and protocol to determine the minimal inhibitory concentration (MIC) and minimal lethal concentration (MLC) of EO gases against microorganisms. A sealed experimental apparatus was constructed for simultaneous evaluation of antimicrobial activities of EO gases at different concentrations without creating concentration gradients. A differential medium was then evaluated in which a color change allowed for the determination of growth of glucose-fermenting microorganisms. Lastly, an experimental protocol for the assessment of MIC and MLC values of EO gases was developed, and these values were determined for 31 EO gases against Escherichia coli O157:H7 as a model bacterium. Results showed that cinnamon bark EO gas had the lowest MIC (0.0391μl/ml), followed by thyme-thymol EO gas (0.0781μl/ml), oregano EO gas (0.3125μl/ml), peppermint EO gas (0.6250μl/ml), and thyme-linalool EO gas (0.6250μl/ml). The order of the MLC values of the EO gases against the E. coli O157:H7 was thyme-thymol (0.0781μl/ml)<cinnamon bark (0.1563μl/ml)<oregano (0.3125μl/ml)<peppermint (0.6250μl/ml)=thyme-linalool (0.6250μl/ml). The experimental apparatus and protocol enable rapid and accurate determination of the MIC and MLC values of EO gases and perhaps other types of gaseous antimicrobial agents.
Characterization of Lactobacillus acidophilus Isolated from Piglets and Chicken
Ahn, Y.T.,Lim, K.L.,Ryu, J.C.,Kang, D.K.,Ham, J.S.,Jang, Y.H.,Kim, H.U. Asian Australasian Association of Animal Productio 2002 Animal Bioscience Vol.15 No.12
Lactic acid bacteria were isolated from piglets and chicken and characterized. Lactic acid bacteria showing resistance to low pH and bile, adhesion to intestinal epithelium cells, and the inhibition of Escherichia coli and Salmonella spp. were identified as Lactobacillus acidophilus. L. acidophilus PF01 survived for 2 h in MRS broth adjusted to pH 2. L. acidophilus CF07 was less resistant than L. acidophilus PF01 to pH 2, but survived at pH 2.5 for 2 h. Both of isolates were able to grow in MRS broth containing 0.3% (w/v) bile, with L. acidophilus CF07 being more tolerant to bile than L. acidophilus PF01. L. acidophilus PF01 and CF07 adhered specifically to the duodenal and jejunal epithelium cells of piglet, and the cecal and duodenal epithelium cells of chicken, respectively. Both of isolates did not adhere to the epithelium cells of the various animal intestines from which they were isolated. When L. acidophilus was cultured with E. coli and Salmonella spp. in MRS broth, MRS broth containing 2% skim milk powder or modified tryptic soy broth at $37^{\circ}C$, L. acidophilus PF01 and CF07 inhibited the growths of E. coli K88 and K99, and S. enteritidis and S. typhimurium, respectively. Both of isolates were found to possess the essential characteristics of probiotic lactic acid bacteria for piglet and chicken.