Hyun Dong Paik

Effect of anthocyanins on expression of matrix metalloproteinase-2 in naproxen-induced gastric ulcers.

Non-steroidal anti-inflammatory drugs cause gastric ulceration through a number of mechanisms including inhibition of PG synthesis, generation of reactive oxygen species (ROS) and induction of apoptosis. Recently, matrix metalloproteinases (MMP) have been suggested to play a crucial role in these mechanisms. The present study investigated the protective effect of anthocyanins isolated from black rice bran (Heugjinjubyeo) against naproxen-induced gastric mucosal injury in rats. The oral administration of anthocyanins (5, 25 or 50xa0mg/kg body weight) showed significant protection against naproxen (80xa0mg/kg body weight)-induced gastric ulcer and inhibited lipid peroxidation in the gastric mucosa. In addition, pretreatment with anthocyanins resulted in a significant increase in the activities of radical-scavenging enzymes such as superoxide dismutase, catalase and glutathione peroxidase. Also biochemical and zymographic analyses suggested that the administration of anthocyanins gives a significant protection against naproxen-induced gastric antral ulcer through scavenging ROS and regulation of matrix metalloproteinase-2 (MMP-2) activity. The results of intracellular radical activation show that anthocyanins suppress the generation of intracellular ROS and attenuate the suppression of MMP-2 activity by naproxen. These results suggest that anthocyanins extracted from black rice may offer potential remedy of gastric antral ulceration.

Physical and functional interaction of FgFtr1–FgFet1 and FgFtr2–FgFet2 is required for iron uptake in Fusarium graminearum

FgFtr1 and FgFtr2 are putative iron permeases, and FgFet1 and FgFet2 are putative ferroxidases of Fusarium graminearum. They have high homologies with iron permease ScFtr1 and ferroxidase ScFet3 of Saccharomyces cerevisiae at the amino acid level. The genes encoding iron permease and ferroxidase were localized to the same chromosome in the manner of FgFtr1/FgFet1 and FgFtr2/FgFet2. The GFP (green fluorescent protein)-fused versions of FgFtr1 and FgFtr2 showed normal functions when compared with FgFtr1 and FgFtr2 in an S. cerevisiae system, and the cellular localizations of FgFtr1 and FgFtr2 in S. cerevisiae depended on the expression of their putative ferroxidase partners FgFet1 and FgFet2 respectively. Although FgFtr1 was found on the plasma membrane when FgFet1 and FgFtr1 were co-transformed in S. cerevisiae, most of the FgFtr1 was found in the endoplasmic reticulum compartment when co-expressed with FgFet2. Furthermore, FgFtr2 was found on the vacuolar membrane when FgFet2 was co-expressed. From the two-hybrid analysis, we confirmed the interaction of FgFtr1 and FgFet1, and the same result was found between FgFtr2 and FgFet2. Iron-uptake activity also depended on the existence of the respective partner. Finally, the FgFtr1 and FgFtr2 were found on the plasma and vacuolar membrane respectively, in F. graminearum. Taken together, these results strongly suggest that FgFtr1 and FgFtr2 from F. graminearum encode the iron permeases of the plasma membrane and vacuolar membrane respectively, and require their specific ferroxidases to carry out normal function. Furthermore, the present study suggests that the reductive iron-uptake system is conserved from yeast to filamentous fungi.

Eight weeks of conjugated linoleic acid supplementation has no effect on antioxidant status in healthy overweight/obese Korean individuals.

PurposeThe aim of this study was to evaluate the effect of CLA supplementation on antioxidant metabolism in healthy overweight/obese Korean individuals.MethodsWe performed a randomized, double-blind, placebo-controlled trial, where 29 healthy overweight/obese (BMIxa0≥xa023xa0kg/m2) participants (2 men and 27 women) were randomly selected to receive placebo (nxa0=xa015, 2.4xa0g olive oil/day) or 2.4xa0g/day CLA mixture (nxa0=xa014, 36.9% of cis-9, trans-11 and 37.9% of trans-10, cis-12) for 8xa0weeks.ResultsThere were no significant differences in plasma total radical-trapping antioxidant potential (TRAP), lipid peroxidation (conjugated dienes), lipid-soluble antioxidant vitamin concentration, erythrocyte antioxidant enzyme (superoxide dismutase, catalase, glutathione peroxidase) activities, and leukocyte DNA damage between the CLA and placebo groups.ConclusionsThe data suggest that short-term supplementation (8xa0weeks) with CLA (2.4xa0g/day) might have no significant effects on lipid peroxidation and antioxidant metabolism.

Genome sequence analysis of H5N1 influenza a virus isolated from a vietnamese in 2007

Highly pathogenic H5N1 avian influenza A virus (AIV) crossed the species barrier and caused a number of deaths in humans in Vietnam and 14 other countries. Since the last report of human H5N1 infection in November 2005, the first documented H5N1 human infection was reported in June 2007 in Vietnam and was followed by 7 more cases, including 5 fatalities. In this study, we isolated and analyzed the full length of the H5N1 genome from a sample from the first patient in 2007. Phylogenetic analysis of eight genomic segments of the H5N1 virus strain (A/Vietnam/HN/2007, VNH07) revealed that this strain appears to be of genotype V and contains the HA gene, which is classified into clade 2.3.4. The deduced amino acid sequence of the HA protein has a typical affinity sequence for α2,3 linkage (SAα2,3-Gal) receptors and typical multibasic cleavage sequences. Compared with other H5N1 isolates, VNH07 showed that the possible reassortments for the NA and NP segments occurred between A/goose/Guangxi/3017/2005-like iso?lates (2.3.2) and A/human/Zhejiang/16/2006-like isolates (2.3.4).

Combined effects of whey protein hydrolysates and probiotics on oxidative stress induced by an iron-overloaded diet in rats

Abstract Whey proteins possess antioxidant properties, and probiotics have various health-promoting effects. We investigated the effects of whey protein hydrolysates (WPHs) and probiotics in rats exposed to oxidative stress induced by iron-overload diet (IOL). Rats were divided into control (CTRL), IOL (0.2% ferrous sulphate), WPH (10%), probiotic (PB) mixture (Lactococcus lactis NK34 and B. polyfermenticus SCD), and WPHu2009+u2009PB group for 6u2009weeks. Average leukocytes and colonocytes tail moments were increased in IOL compared to CTRL but decreased in other groups. Conjugated diene was lower in WPH, PB, and WPHu2009+u2009PB than in IOL. Only WPHu2009+u2009PB group could recover glutathione S-transferase (GST) levels. SOD levels were recovered by WPH and PB. PB and WPHu2009+u2009PB increased α-tocopherol and only WPHu2009+u2009PB increased γ-tocopherol. Thus, our data demonstrated that WPH and PB exhibit antioxidant properties in a rat model of high-iron diet-induced oxidative stress and combination of them may provide an enhanced effect. Graphical Abstract

Antimicrobial Characterization of Inula britannica against Helicobacter pylori on Gastric Condition

The antimicrobial effects of methanol and ethanol extracts of Inula britannica against several Helicobacter pylori strains (26695, J99, and SS1) were evaluated in vitro, to determine their applicability as functional foods. In the paper disc diffusion method, the antimicrobial effects of the I. britannica extracts against the H. pylori strains were apparent. Viable cell counting also showed that the extracts at 100 μg/ml concentration dramatically decreased the viability of the H. pylori strains. In particular, the methanol and ethanol extracts at a concentration of 100 μg/ml reduced the H. pylori SS1 cell number to 2.46 log CFU/ml and 1.08 log CFU/ml, respectively. In the presence of 100 μg/ml extracts, the urease production of H. pylori SS1 was decreased to more than 30%, whereas that of H. pylori J99 and H. pylori 26695 was decreased to about 20%, relative to the controls. The extracts inhibited the attachment of the H. pylori strains to human gastric AGS cells as well as caused the detachment of already attached H. pylori cells. In addition, the H. pylori morphology was changed to a coccoidal shape in the presence of the extracts. In conclusion, the I. britannica extracts were effective against H. pylori strains in vitro, irrespective of genotype status, and could therefore be used as novel functional foods.

New and efficient method using Saccharomyces cerevisiae mutants for identification of siderophores produced by microorganisms.

The separation and identification of siderophores produced by microorganisms is a time-consuming and an expensive procedure. We have developed a new and efficient method to identify siderophores using well-established Saccharomyces cerevisiae deletion mutants. The Δfet3,arn strains fail to sustain growth, even when specific siderophores are supplied, and mutants are siderophore-specific: Δfet3,arn2 for triacetylfusarinine C (TAFC), Δfet3,arn1,sit1 for ferrichrome (FC), and Δfet3,sit1 for ferrioxamine B (FOB). The culture broth of Fusarium graminearum was separated by HPLC, and each peak was subjected to a plate assay using S. cerevisiae mutants. We have found that each peak contained specific siderophores produced by F. graminearum, and these coincided with reference siderophores. This method is quite novel because nobody tried this method to identify the siderophores. Furthermore, this method will save time and cost in the identification of siderophores produced by microorganisms.