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Xinlong He,안주희 한국미생물학회 2014 The journal of microbiology Vol.52 No.8
This study was designed to evaluate the transfer potential ofantibiotic resistance genes in antibiotic-resistant SalmonellaTyphimurium (S. TyphimuriumR) in the presence of bilesalts. The resistance of S. TyphimuriumR to ampicillin, kanamycin,and tetracycline was increased by 64-, 64-, and 512-fold, respectively. The highest transfer frequency from S. TyphimuriumR to Escherichia coli was observed at the bilesalt concentration of 160 μg/ml (3.8 × 10-3 transferrants/cells). The expression of traJ and traY was suppressed in S. TyphimuriumRby bile salt. This study provides useful informationfor understanding the conjugative transfer of antibiotic resistancegenes in S. Typhimurium under intestinal conditions.
HE, XINLONG,ZOU, YUNYUN,CHO, YOUNGJAE,AHN, JUHEE International Association for Food Protection 2012 Journal of food protection Vol.75 No.6
<P>This study was designed to evaluate the effects of bile acid deconjugation by probiotic strains on the antibiotic susceptibility of antibiotic-sensitive and multiple antibiotic-resistant Salmonella Typhimurium and Staphylococcus aureus. Eight probiotic strains, Bifidobacterium longum B6, Lactobacillus acidophilus ADH, Lactobacillus brevis KACC 10553, Lactobacillus casei KACC 12413, Lactobacillus paracasei ATCC 25598, Lactobacillus rhamnosus GG, Leuconostoc mesenteroides KACC 12312, and Pediococcus acidilactici KACC 12307, were used to examine bile acid tolerance. The ability to deconjugate bile acids was evaluated using both thin-layer chromatography and high-performance liquid chromatography. The antibiotic susceptibility testing was carried out to determine the synergistic inhibitory activity of deconjugated bile acids. L. acidophilus, L. brevis, and P. acidilactici showed the most tolerance to the conjugated bile acids. P. acidilactici deconjugated glycocholic acid and glycodeoxycholate from 3.18 and 3.09 mM to the detection limits, respectively. The antibiotic susceptibility of selected foodborne pathogens was increased by increasing the concentration of deconjugated bile acids. The study results are useful for understanding the relationship between bile acid deconjugation by probiotic strains and antibiotic susceptibility in the presence of deconjugated bile acids, and they may be useful for designing new probiotic-antibiotic combination therapy based on bile acid deconjugation.</P>
Xinlong He,안주희,윤원병,박성진,Dong-Sik Park 한국식품과학회 2011 Food Science and Biotechnology Vol.20 No.2
This study was designed to evaluate the effect of high pressure treatment on the extraction properties of deodeok (Codonopsis lanceolata) as measured by total phenols, flavonoids, phenolic acids, radical scavenging activity, and cytotoxicity. Deodeok was subjected to different pressure levels (0.1-500 MPa) and extraction times (0-30min). The highest amounts of total phenols and flavonoids were 648 and 130 μg RE/mL at 300 MPa for 20 min,respectively. The optimizing conditions for the pressureassisted water extraction (PAWE) of deodeok as a function of pressure level and extraction time were 385 MPa and 25min for total phenols (633 μg GAE/mL) and 405 MPa and 24 min for flavonoids (124 μg RE/mL). The PAWE significantly increased the amount of vanillic acid (41 μg/mL) in deodeok extract compared to the conventional extraction (CE, 17 μg/mL). The highest radical scavenging activity (81%) of deodeok extract was achieved at the treatment of 500 MPa and 30 min. The PAWE can increase biologically active components in deodeok by considering process variables such as pressure level and extraction time. The results provide useful information towards improving pharmaceutical properties of medicinal plants and herbs using the PAWE.
He, Xinlong,Ahn, Juhee Published by Elsevier/North Holland on behalf of t 2011 FEMS microbiology letters Vol.325 No.2
<P>This study was designed to evaluate gene expression patterns of the planktonic and biofilm cells of Staphylococcus aureus and Salmonella Typhimurium in trypticase soy broth adjusted to pH 5.5 and pH 7.3. The planktonic and biofilm cells of multiple antibiotic-resistant S. aureus (S. aureus(R) ) and S. Typhimurium (S. Typhimurium(R) ) were more resistant to β-lactams than those of antibiotic-susceptible S. aureus (S. aureus(S) ) and S. Typhimurium (S. Typhimurium(S) ) at pH 5.5 and pH 7.3. The relative gene expression levels of norB, norC, and mdeA genes were increased by 7.0-, 4.7-, and 4.6-fold, respectively, in the biofilm cells of S. aureus(S) grown at pH 7.3, while norB, norC, mdeA, sec, seg, sei, sel, sem, sen, and seo genes were stable in the biofilm cells of S. aureus(R) . This study provides useful information for understanding gene expression patterns in the planktonic and biofilm cells of antibiotic-resistance pathogens exposed to acidic stress.</P>
He, Xinlong,Ahn, Juhee Blackwell Publishing Ltd 2011 International journal of food science & technology Vol.46 No.10
<P><B>Summary</B></P><P>The transit tolerance and relative gene expression (<I>acrA</I>, <I>acrB</I>, <I>tolC</I>, <I>stn</I>, <I>hilA</I> and <I>ompD</I>) were observed in antibiotic‐sensitive <I>Salmonella</I> Typhimurium (ASST) and antibiotic‐resistant <I>S.</I> Typhimurium (ARST) exposed to simulated gastric juices (pH 2.0, pH 3.0 and pH 5.0) for 1 or 4 h, followed by small intestinal juices (0.1% and 0.5% bile salts) for 2 h. The relative expression of <I>acrA</I>, <I>acrB</I>, <I>tolC</I>, <I>stn</I>, <I>hilA</I> and <I>ompD</I> in the ARST was upregulated after exposure to simulated gastrointestinal juices. The expression of AcrAB‐TolC efflux system in ARST was highly correlated with the expression of <I>stn</I> and <I>hilA</I> encoding virulence factor and regulator. The cross‐protective effect was observed in ARST against the gastric acid and bile salts. The AcrAB‐TolC involved in enhanced survival and virulence potential, resulting in increased in pathogenicity of ARST. This study provides useful information for assessing the gastrointestinal transit tolerance and virulence potential of multiple antibiotic‐resistant pathogens.</P>
He, Xinlong,Zou, Yunyun,Yoon, Won-Byong,Park, Sung-Jin,Park, Dong-Sik,Ahn, Juhee Elsevier 2011 Journal of bioscience and bioengineering Vol.112 No.2
<P><B>Abstract</B></P><P>This study was designed to evaluate the enhancement of antioxidant, antimicrobial, enzymatic, cytotoxic, and cognitive activities of <I>Codonopsis lanceolata</I> extracted by high pressure treatment followed by probiotic fermentation. Dried <I>C</I>. <I>lanceolata</I> samples were subjected to 400MPa for 20min and then fermented with <I>Bifidobacterium longum</I> B6 (HPE-BLF) and <I>Lactobacillus rhamnosus</I> (HPE-LRF) at 37°C for 7days. Compared to conventional extraction (CE-NF, 6.69mg GAE/g), the phenol amounts of HPE-BLF and HPE-LRF were significantly increased to more than 8mg GAE/g, while the lowest flavonoid contents were observed for HPE-BLF (0.44mg RE/mL) and HPE-LRF (0.45mg RE/mL) (<I>p</I><0.05). Cinnamic acid was the most abundant phenolic acid in the fermented <I>C</I>. <I>lanceolata</I>. The highest DPPH scavenging activities were observed for HPE-BLF and HPE-LRF, with minimum EC<SUB>50</SUB> values of 1.26 and 1.18mg/mL, respectively. The HPE-BLF and HPE-LRF samples exhibited the most noticeable antimicrobial activities against <I>Staphylococcus aureus</I>, <I>Listeria monocytogenes</I>, <I>Salmonella</I> Typhimurium, and <I>Shigella boydii</I> (MICs<15mg/mL). The fermented <I>C</I>. <I>lanceolata</I> samples effectively inhibited α-glucosidase and tyrosinase activities and potentially improved a scopolamine-induced memory deficit in mice. The application of a fermentation process can effectively improve the biological and pharmacological activities of high-pressure-extracted <I>C</I>. <I>lanceolata</I> by increasing the extraction efficacy and inducing probiotic conversion. The results suggest that the combined treatment of HPE and a fermentation process could be used as alternative extraction method over CE.</P>
정래승,Xinlong He,송치호,마충제,이현용,안주희 한국식품과학회 2012 Food Science and Biotechnology Vol.21 No.5
This study was designed to evaluate the antioxidant, antimicrobial, antibiofilm, and anticholinesterase activities of different solvent fractions from non-fermented (NF) and Lactobacillus rhamnosus fermented deodeok (Codonopsis lanceolata) (LRF). The highest amounts of total phenols and flavonoids were observed in chloroform fraction from NF (72 and 31 mg RE/g) and LRF (79 and 24 mg RE/g). The ferric reducing antioxidant power (FRAP) values were highly correlated with the DPPH scavenging activity, showing that the highest FRAP values were observed in chloroform fractions from NF (35 mM Fe(II)/g) and LRF (50 mM Fe(II)/g). Staphylococcus aureus biofilm cells were highly susceptible to chloroform fraction, showing 1.8 log reductions. The highest anticholinesterase activity was observed in chloroform and ethyl acetate fractions from LRF (1.5 mg/mL<EC50<2.5mg/mL). The results provide useful information for improving pharmacological activities and also suggest new direction for developing biologically active compounds from medicinal plants.