Heat Tolerances of Salmonella, Cronobacter sakazakii, and Pediococcus acidilactici Inoculated into Galactooligosaccharide

Bang, Jihyun,Choi, Moonkak,Jeong, Haeseok,Lee, Sangseob,Kim, Yoonbin,Ryu, Jee-Hoon,Kim, Hoikyung ational Association for Food Protection 2017 Journal of food protection Vol. No.

<B>ABSTRACT</B><P>Food-grade galactooligosaccharide (GOS) with low water activity (aw of ca. 0.7) is used as an ingredient in various foods. We evaluated heat tolerances of Salmonella, Cronobacter sakazakii, and Pediococcus acidilactici at temperatures (70 to 85°C) used during the saturation process of GOS by comparing decimal reduction time (D-values) and thermal resistance constants (z-values). To determine the D- and z-values, GOS containing Salmonella (5.1 to 5.8 log CFU/g) or C. sakazakii (5.3 to 5.9 log CFU/g) was heat treated at 70, 77.5, or 85°C for up to 40, 25, or 15 s, respectively, and GOS containing P. acidilactici (6.1 to 6.5 log CFU/g) was heat treated at 70, 77.5, or 85°C for up to 150, 75, or 40 s, respectively. The D-values were calculated using a linear model for heating time versus microbial population for each bacterium. When the D-values for Salmonella, C. sakazakii, and P. acidilactici in GOS were compared, the thermal resistance of all bacteria decreased as the temperature increased. Among the three bacteria, P. acidilactici had higher D-values than did Salmonella and C. sakazakii. The z-values of Salmonella, C. sakazakii, and P. acidilactici were 30.10, 33.18, and 13.04°C, respectively. Overall order of thermal resistance was P. acidilactici &gt; Salmonella ≈ C. sakazakii. These results will be useful for selecting appropriate heat treatment conditions for the decontamination of pathogenic microorganisms during GOS manufacturing.</P>

다양한 식중독균과 식물병원균에 항균력을 갖는 토양유래 Streptomyces Virginiae의 분리

방지현(Bang, Jihyun) 한국생활과학회 2016 한국생활과학회지 Vol.25 No.5

We identified a microorganism with inhibitory activities against foodborne pathogens (Escherichia coli O157:H7, Listeria monocytogenes, Staphylococcus aureus, and Vibrio parahaemolyticus) and plant pathogens (Aspergillus flavus and Fusarium graminearum). A total of 2,106 microorganisms were obtained from soil, foods or food contact surfaces for isolation of the antagonistic microorganism. The antimicrobial activities of the isolates were determined against six pathogenic microorganisms using a double-layer assay. Only one microorganism showed inhibitory activity against the six pathogenic microorganisms. The microorganism was identified as Streptomyces virginiae by 16S rRNA gene sequence analysis and cultural characteristics in international Streptomyces project (ISP) media.

Asymmetric Aldol Reaction of Allenoates: Regulation for the Selective Formation of Isomeric Allenyl or Alkynyl Aldol Adduct

Bang, Jiyun,Kim, Hyuna,Kim, Jihyun,Yu, Chan-Mo American Chemical Society 2015 ORGANIC LETTERS Vol.17 No.6

<P>A highly stereoselective synthesis of 3-butynyl-<I>threo</I>-aldol adducts is achieved from the reaction of allyl allenoate with a chiral bromoborane in the presence of <I>i</I>Pr<SUB>2</SUB>NEt, followed by addition of BF<SUB>3</SUB>·OEt<SUB>2</SUB> as an additive to scavenge excess base and then aldehydes, whereas isomeric allenyl aldol adducts are formed in the absence of a Lewis acid additive from methyl allenoate.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/orlef7/2015/orlef7.2015.17.issue-6/acs.orglett.5b00454/production/images/medium/ol-2015-00454t_0009.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/ol5b00454'>ACS Electronic Supporting Info</A></P>

Taxifolin Glycoside Blocks Human ether-a-go-go Related Gene K<SUP>+</SUP> Channels

Jihyun Yun,Hyemi Bae,Sun Eun Choi,Jung-Ha Kim,Young Wook Choi,Inja Lim,Chung Soo Lee,Min Won Lee,Jae-Hong Ko,Seong Jun Seo,Hyoweon Bang 대한생리학회-대한약리학회 2013 The Korean Journal of Physiology & Pharmacology Vol.17 No.1

Taxifolin glycoside is a new drug candidate for the treatment of atopic dermatitis (AD). Many drugs cause side effects such as long QT syndrome by blocking the human ether-a-go-go related gene (hERG) K⁺ channels. To determine whether taxifolin glycoside would block hERG K⁺ channels, we recorded hERG K⁺ currents using a whole-cell patch clamp technique. We found that taxifolin glycoside directly blocked hERG K⁺ current in a concentration-dependent manner (EC₅₀=9.6±0.7ՌM). The activation curve of hERG K⁺ channels was negatively shifted by taxifolin glycoside. In addition, taxifolin glycoside accelerated the activation time constant and reduced the onset of the inactivation time constant. These results suggest that taxifolin glycoside blocks hERG K⁺ channels that function by facilitating activation and inactivation process.

Improved pregnancy rate and sex ratio in fresh/frozen in vivo derived embryo transfer of Hanwoo (Bos taurus coreanae) cows

Jihyun Park,Wonyou Lee,Islam M. Saadeldin,Seonggyu Bang,Sang Hoon Lee,이준구,Jong Ki Cho 한국축산학회 2023 한국축산학회지 Vol.65 No.4

This study aimed to assess the effects of embryonic developmental stage, quality grade, and fresh or frozen/thawed conditions on the pregnancy rate and sex ratio of live offspring in Hanwoo (Bos taurus coreanae) cows. The quality and developmental stage of in vivo-derived (IVD) transferred embryos were evaluated using the standard criteria of the International Embryo Technology Society. The recipient cows were synchronized using conventional (estradiol benzoate and progesterone) protocols before embryo transfer. Embryos were transferred to 297 cows, and pregnancy was monitored for 60–70 days after embryo transfer. The pregnancy rates of fresh and frozen/thawed embryos were 56.90% and 52.49%, respectively. Pregnancy rates varied according to embryo quality (56.18% for grade 1 vs. 36.67% for grade 2). Pregnancy rates also varied by developmental stage and cryopreservation (67.86% vs. 63.49% for stage 4-1, 64.00% vs. 54.72% for 5-1, and 50.00% vs. 47.83% for 6-1, in fresh embryos vs. frozen/thawed embryos, respectively). For stage 7-1, the pregnancy rates were 72.73% for fresh embryos and 20.00% for frozen/thawed embryos. In 66 fresh embryos, the sex ratio of live offspring was 5:5, whereas it was 4(female):6(male) for frozen/thawed embryos among the 95 frozen/thawed embryos. The miscarriage rate was approximately 3% higher for frozen/thawed embryos than for fresh embryos (18.1% for fresh vs. 21.1% for frozen). Seasonal fertility rates were 33.3% in spring, 55.67% in summer, 52.8% in autumn, 60.0% in winter. The following male-to-female ratios were observed in different seasons: 6.7:3.3 in spring, 4.0:6.0 in summer, 5.5:4.5 in autumn, and 3.3:6.7 in winter. The current data revealed no significant differences in pregnancy rates between fresh and frozen/thawed IVD embryos. However, there was a lower pregnancy rate with advanced-stage frozen/thawed embryos (stage 7-1). The current study provides comprehensive results for the better optimization of embryo transfer in Hanwoo cattle to obtain the desired fertility rate, pregnancy rate, and sex ratio of calves. These results provide important insights into the factors that influence the viability and success of IVD embryo transfer in Hanwoo cows and may have practical applications for improving breeding programs and reducing production costs.

Effects of Pharmacological Modulators of Ca<SUP>2⁢</SUP>-activated K<SUP>⁢</SUP> Channels on Proliferation of Human Dermal Fibroblast

Jihyun Yun,Taeho Kim,Soonchul Myung,Hyoweon Bang,Inja Lim 대한생리학회-대한약리학회 2006 The Korean Journal of Physiology & Pharmacology Vol.10 No.2

Employing electrophysiological and cell proliferation assay techniques, we studied the effects of Ca<SUP>2⁢</SUP>- activated K<SUP>⁢</SUP> channel modulators on the proliferation of human dermal fibroblasts, which is important in wound healing. Macroscopic voltage-dependent outward K<SUP>⁢</SUP> currents were found at about ⁣40 mV stepped from a holding potential of ⁣70 mV. The amplitude of K<SUP>⁢</SUP> current was increased by NS1619, a specific large-conductance Ca<SUP>2⁢</SUP>-activated K<SUP>⁢</SUP> (BK) channel activator, but decreased by iberiotoxin (IBTX), a specific BK channel inhibitor. To investigate the presence of an intermediate-conductance Ca<SUP>2⁢</SUP>-activated K<SUP>⁢</SUP> (IK) channels, we pretreated the fibroblasts with low dose of TEA to block BK currents, and added 1-EBIO (an IK activator). 1-EBIO recovered the currents inhibited by TEA. When various Ca<SUP>2⁢</SUP>-activated K<SUP>⁢</SUP> channel modulators were added into culture media for 1∼3 days, NS1619 or 1-EBIO inhibited the cell proliferation. On the other hand, IBTX, clotrimazole or apamin, a small conductance Ca<SUP>2⁢</SUP>-activated K<SUP>⁢</SUP> channel (SK) inhibitor, increased it. These results suggest that BK, IK, and SK channels might be involved in the proliferation of human dermal fibroblasts, which is inversely related to the channel activation.

Modulation of Large Conductance Ca<SUP>2⁢</SUP>-activated K<SUP>⁢</SUP> Channel of Skin Fibroblast (CRL-1474) by Cyclic Nucleotides

Jihyun Yun,Seungtae Kim,Hyoweon Bang 대한생리학회-대한약리학회 2005 The Korean Journal of Physiology & Pharmacology Vol.9 No.2

Potassium channels in human skin fibroblast have been studied as a possible site of Alzheimer disease pathogenesis. Fibroblasts in Alzheimer disease show alterations in signal transduction pathway such as changes in Ca<SUP>2⁢</SUP> homeostasis and/or Ca<SUP>2⁢</SUP>-activated kinases, phosphatidylinositol cascade, protein kinase C activity, cAMP levels and absence of specific K<SUP>⁢</SUP> channel. However, little is known so far about electrophysiological and pharmacological characteristics of large-conductance Ca<SUP>2⁢</SUP>-activated K<SUP>⁢</SUP> (BK<SUB>Ca</SUB>) channel in human fibroblast (CRL-1474). In the present study, we found Iberiotoxin- and TEA-sensitive outward rectifying oscillatory current with whole-cell recordings. Single channel analysis showed large conductance K<SUP>⁢</SUP> channels (106 pS of chord conductance at ⁢40 mV in physiological K<SUP>⁢</SUP> gradient). The 106 pS channels were activated by membrane potential and [Ca<SUP>2⁢</SUP>]<SUB>i</SUB>, consistent with the known pro</SUB>perties of BK<SUB>Ca</SUB> channels. BK<SUB>Ca</SUB> channels in CRL-1474 were positively regulated by adenylate cyclase activator (10μM forskolin), 8-Br-cyclic AMP (300μM) or 8-Br-cyclic GMP (300μM). These results suggest that human skin fibroblasts (CR-1474) have typical BK<SUB>Ca</SUB> channel and this channel could be modulated by c-AMP and c-GMP. The electrophysiological characteristics of fibroblasts might be used as the diagnostic clues for Alzheimer disease.

TASK-1 Channel Promotes Hydrogen Peroxide Induced Apoptosis

Jihyun Yun,Seungtae Kim,Hyoweon Bang 대한생리학회-대한약리학회 2005 The Korean Journal of Physiology & Pharmacology Vol.9 No.1

Hydrogen peroxide (H<SUB>2</SUB>O<SUB>2</SUB>) causes oxidative stress and is considered as an inducer of cell death in various tissues. Two-pore domain K<SUP>⁢</SUP> (K<SUB>2p</SUB>) channels may mediate K<SUP>⁢</SUP> efflux during apoptotic volume decreases (AVD) in zygotes and in mouse embryos. In the present study, we sought to elucidate linkage between K<SUB>2p</SUB> channels and cell death by H<SUB>2</SUB>O<SUB>2</SUB>. Thus K<SUB>2p</SUB> channels (TASK-1, TASK-3, TREK-1, TREK-2) were stably transfected in HEK-293 cells, and cytotoxicity assay was preformed using cell counting kit-8 (CCK-8). Cell survival rates were calculated using the cytotoxicity assay data and dose-response curve was fitted to the H<SUB>2</SUB>O<SUB>2</SUB> concentration. Ionic currents were recorded in cell-attached mode. The bath solution was the normal Ringer solution and the pipette solution was high K<SUP>⁢</SUP> solution. In HEK-293 cells expressing TREK-1, TREK-2, TASK-3, H<SUB>2</SUB>O<SUB>2</SUB> induced cell death did not change in comparison to non-transfected HEK-293. In HEK-293 cells expressing TASK-1, however, dose-response curve was significantly shifted to the left. It means that H<SUB>2</SUB>O<SUB>2</SUB> induced cell death was increased. In cell attached-mode recording, application of H<SUB>2</SUB>O<SUB>2</SUB> (300μM) increased activity of all K<SUB>2P</SUB> channels. However, a low concentration of H<SUB>2</SUB>O<SUB>2</SUB> (50μM) increased only TASK-1 channel activity. These results indicate that TASK-1 might participate in K<SUP>⁢</SUP> efflux by H<SUB>2</SUB>O<SUB>2</SUB> at low concentration, thereby inducing AVD.

Anti-obesity effects of Rapha diet<SUP>®</SUP> preparation in mice fed a high-fat diet

Jihyun Kim,Jangbeen Kyung,Dajeong Kim,Ehn-Kyoung Choi,Paul Bang,Dongsun Park,Yun-Bae Kim 한국실험동물학회 2012 Laboratory Animal Research Vol.28 No.4

The anti-obesity activities of Rapha diet<SUP>®</SUP> preparation containing silkworm pupa peptide, Garcinia cambogia, white bean extract, mango extract, raspberry extract, cocoa extract, and green tea extract were investigated in mice with dietary obesity. Male C57BL/6 mice were fed a high-fat diet (HFD) containing 3% Rapha diet<SUP>®</SUP> preparation for 8 weeks, and blood and tissue parameters of obesity were analyzed. The HFD markedly enhanced body weight gain by increasing the weights of epididymal, perirenal, and mesenteric adipose tissues. The increased body weight gain induced by HFD was significantly reduced by feeding Rapha diet<SUP>®</SUP> preparation, in which decreases in the weight of abdominal adipose tissue and the size of abdominal adipocytes were confirmed by microscopic examination. Long-term feeding of HFD increased blood triglycerides and cholesterol levels, leading to hepatic lipid accumulation. However, Rapha diet<SUP>®</SUP> preparation not only reversed the blood lipid levels, but also attenuated hepatic steatosis. The results indicate that Rapha diet<SUP>®</SUP> preparation could improve HFD-induced obesity by reducing both lipid accumulation and the size of adipocytes.

Major AhR-active chemicals in sediments of Lake Sihwa, South Korea: Application of effect-directed analysis combined with full-scan screening analysis

Cha, Jihyun,Hong, Seongjin,Kim, Jaeseong,Lee, Junghyun,Yoon, Seo Joon,Lee, Sunggyu,Moon, Hyo-Bang,Shin, Kyung-Hoon,Hur, Jin,Giesy, John P.,Khim, Jong Seong Elsevier 2019 Environment international Vol.133 No.2

<P><B>Abstract</B></P> <P>This study utilized effect-directed analysis (EDA) combined with full-scan screening analysis (FSA) to identify aryl hydrocarbon receptor (AhR)-active compounds in sediments of inland creeks flowing into Lake Sihwa, South Korea. The specific objectives were to (i) investigate the major AhR-active fractions of organic extracts of sediments by using H4IIE-<I>luc in vitro</I> bioassay (4 h and 72 h exposures), (ii) quantify known AhR agonists, such as polycyclic aromatic hydrocarbons (PAHs) and styrene oligomers (SOs), (iii) identify unknown AhR agonists by use of gas chromatography-quadrupole time-of-flight mass spectrometry (GC-QTOFMS), and (iv) determine contributions of AhR agonists to total potencies measured by use of the bioassay. FSA was conducted on fractions F2.6 and F2.7 (aromatics with log K<SUB>ow</SUB> 5–7) in extracts of sediment from Siheung Creek (industrial area). Those fractions exhibited significant AhR-mediated potency as well as relatively great concentrations of PAHs and SOs. FSA detected 461 and 449 compounds in F2.6 and F2.7, respectively. Of these, five tentative candidates of AhR agonist were selected based on NIST library matching, aromatic structures and numbers of rings, and available standards. Benz[<I>b</I>]anthracene, 11H-benzo[<I>a</I>]fluorene, and 4,5-methanochrysene exhibited significant AhR-mediated potency in the H4IIE-<I>luc</I> bioassay, and relative potencies of these compounds were determined. Potency balance analysis demonstrated that these three newly identified AhR agonists explained 1.1% to 67% of total induced AhR-mediated potencies of samples, which were particularly great for industrial sediments. Follow-up studies on sources and ecotoxicological effects of these compounds in coastal environments would be required.</P> <P><B>Highlights</B></P> <P> <UL> <LI> EDA combined with FSA identified unknown toxicants in industrial sediments. </LI> <LI> Benz[<I>b</I>]anthracene, 11H-benzo[<I>a</I>]fluorene, and 4,5-methanochrysene are novel AhR agonists. </LI> <LI> Benz[<I>b</I>]anthracene showed 10-fold greater AhR potency compared to benzo[<I>a</I>]pyrene. </LI> <LI> Newly identified AhR agonists significantly contributed to AhR potencies from sediments. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>