Different Regions Of South Korea Research Articles

Relationship between total phenolic contents and biological properties of propolis from 20 different regions in South Korea

BackgroundPropolis (or bee glue), collected from botanical sources by honey bee, has been used as a popular natural remedies in folk medicine throughout the world. This study was conducted to assess growth inhibitory effects of ethanol extracts of propolis (EEPs) from 20 different regions in South Korea on human intestinal bacteria as well as their human β-amyloid precursor cleavage enzyme (BACE-1), acetylcholinesterase (AChE) inhibitory, antioxidant, antiproliferative, and anti-human rhinovirus activities.MethodsThe Bonferroni multiple-comparison method was used to test for significant differences in total polyphenol and flavonoid contents among EEP samples using SAS 9.13 program. Correlation coefficient (r) analysis of the biological activities of EEP samples was determined using their 50 % inhibition concentration or minimal inhibitory concentration values and their polyphenol or flavonoid contents in 20 native Korean EEP samples.ResultsThe amounts of total polyphenol and flavonoids in the Korean EEP samples ranged from 49 to 239 mg gallic acid equivalent (GAE)/g EEP (Brazilian, Chinese, and Australian samples, 127–142 mg GAE/g EEP) and from 21 to 50 mg quercetin equivalent (QE)/g EEP (Brazilian, Chinese, and Australian samples, 33–53 mg QE/g EEP), respectively. Correlation coefficient analysis showed that total polyphenol contents may be negatively correlated with 2,2-diphenyl-1-picrylhydrazyl free radical scavenging activity (r = −0.872) and total flavonoid content has no correlation with the activity (r = 0.071). No direct correlation between BACE-1 inhibition, AChE inhibition, or antiproliferative activity and total polyphenol or total flavonoid content in Korean EEP samples was found. Gram-positive and Gram-negative bacteria were observed to have different degrees of antimicrobial susceptibility to the EEP samples examined, although ciprofloxacin susceptibility among the bacterial groups did not differ greatly.ConclusionsFurther studies will warrant possible applications of propolis as potential therapeutic BACE-1 blocker, antioxidant, antiproliferative agent, and antimicrobial agent.

Compositional analysis of protoporphyrinogen oxidase-inhibiting herbicide-tolerant rice and conventional rice

Summary Protoporphyrinogen oxidase (PPO) is a key enzyme of peroxidising herbicides. Transgenic rice event CPPO06, which overexpresses PPO gene derived from soil bacterium, Myxococcus xanthus, showed high resistance to PPO inhibitors. This study was designed to compare the compositional profile of rice event CPPO06 with that of conventional control and commercial cultivars. Field trials were carried out in the three different regions of South Korea during the 2011 and 2012 growing seasons. After harvesting, brown rice samples were analysed for their proximates, amino acids, fatty acids, minerals and vitamins. Over 2-year field trials, statistical differences between rice event CPPO06 and its control were found for crude protein, aspartic acid, oleic acid, linoleic acid, linolenic acid, copper and potassium. However, all the tested values for these components were both within the 99% tolerance interval for the commercial cultivars and within the literature ranges. It was concluded that rice event CPPO06 is compositionally equivalent to that of the conventional rice.

Comparison of Quality Characteristics and Instrumental Analysis on Korean Makgeolli

To compare different taste evaluating methods on Makgeolli, quality characteristics and instrumental analysis on 41 commercial Makgeolli (unheated 21, heated 20) produced in different regions of South Korea were investigated. Physicochemical characteristics including pH, total titratable acidity, amino-type nitrogen, reducing sugar, and color of Makgeolli samples were analyzed. Sensory characteristics including appearance (turbidity, color), flavor (aroma), taste (sweet, sour, bitter, thick, cool), and total acceptability were evaluated. Five tastes (umami, sour, salty, bitter, astringent) and three after tastes (umami, bitter, astringent) were evaluated by using Taste Sensing System (TS-5000Z). In correlation between analytical values of physicochemical and sensory characteristics, ‘pH, amino-type nitrogen sourness, refreshing, balances’ was showed high correlation. In addition, analytical items between sensory characteristics and Taste Sensing System showed a strong correlation. Results indicate the analytical values of quality characteristics and Taste Sensing System on Makgeolli were highly correlated.

Determination of perchlorate and iodide concentrations in edible seaweeds

Perchlorate and iodide concentrations were determined in brown (Undaria pinnatifida and Laminaria japonica) and red (Porphyra sp.) edible seaweeds, which are commonly consumed by Korean people, with the use of ion chromatography, coupled with a tandem mass spectrometer. Seaweeds (i.e., good sources of iodine) are among the most important plant life in the ocean and commonly consumed as food and nutritional supplement in South Korea. All seaweed samples were purchased from different regions in South Korea. The detected concentrations of perchlorate were as follows: 19.7–620.7 μg kg−1 dry weight (n = 11, mean concentration = 149.2 μg kg−1 dry weight) for L. japonica and 7.3–21.7 μg kg−1 dry weight (mean concentration = 10.6 μg kg−1 dry weight) for U. pinnatifida. Of the 11 samples of Porphyra sp., only 1 sample showed 6.7 μg kg−1 dry weight perchlorate. The concentrations of iodide in all seaweed samples varied from 0.44 to 6,800 mg kg−1 dry weight. L. japonica samples (n = 11) had significantly higher iodide concentrations, with a mean of 5,261 mg kg−1 dry weight. The bioconcentration factor values for perchlorate and iodide in the three different seaweeds varied widely and showed similar variation trends. The trend for perchlorate and iodide was Porphyra sp. < U. pinnatifida < L. japonica. The results have provided growing evidence that perchlorate frequently occurs in food products.

Phylogenetic analysis of black queen cell virus genotypes in South Korea

The black queen cell virus (BQCV), a picorna-like honeybee virus, was first isolated from queen larvae and pupae of honeybees found dead in their cells. BQCV is the most common cause of death in queen larvae. Phylogenetic analysis of two Apis cerana and three Apis mellifera BQCV genotypes collected from honeybee colonies in different regions of South Korea, central European BQCV genotypes, and a South African BQCV reference genotype was performed on a partial helicase enzyme coding region (ORF1) and a partial structural polypeptide coding region (ORF2). The phylogeny based on the ORF2 region showed clustering of all the Korean genotypes corresponding to their geographic origin, with the exception of Korean Am str3 which showed more similarity to the central European and the South African reference genotype. However, the ORF1-based tree exhibited a different distribution of the Korean strains, in which A. cerana isolates formed one cluster and all A. mellifera isolates formed a separate cluster. The RT-PCR assay described in this study is a sensitive and reliable method for the detection and classification of BQCV strains from various regions of Korea. BQCV infection is present in both A. cerana and A. mellifera colonies. With this in mind, the present study examined the transmission of honeybee BQCV infections between A. cerana and A. mellifera.

A Numerical Study of Clear-Air Turbulence (CAT) Encounters over South Korea on 2 April 2007

Abstract On 2 April 2007, nine cases of moderate-or-greater-level clear-air turbulence (CAT) were observed from pilot reports over South Korea during the 6.5 h from 0200 to 0830 UTC. Those CAT events occurred in three different regions of South Korea: the west coast, Jeju Island, and the eastern mountain areas. The characteristics and possible mechanisms of the CAT events in the different regions are investigated using the Weather Research and Forecasting model. The simulation consists of six nested domains focused on the Korean Peninsula, with the finest horizontal grid spacing of 0.37 km. The simulated wind and temperature fields in a 30-km coarse domain are in good agreement with those of the Regional Data Assimilation and Prediction System (RDAPS) analysis data of the Korean Meteorological Administration and observed soundings of operational radiosondes over South Korea. In synoptic features, an upper-level front associated with strong meridional temperature gradients is intensified, and the jet stream passing through the central part of the Korean Peninsula exceeds 70 m s−1. Location and timing of the observed CAT events are reproduced in the finest domains of the simulated results in three different regions. Generation mechanisms of the CAT events revealed in the model results are somewhat different in the three regions. In the west coast area, the tropopause is deeply folded down to about z = 4 km because of the strengthening of an upper-level front, and the maximized vertical wind shear below the jet core produces localized turbulence. In the Jeju Island area, localized mixing and turbulence are generated on the anticyclonic shear side of the enhanced jet, where inertial instability and ageostrophic flow are intensified in the lee side of the convective system. In the eastern mountain area, large-amplitude gravity waves induced by complex terrain propagate vertically and subsequently break down over the lee side of topography, causing localized turbulence. For most of the CAT processes considered, except for the mountain-wave breaking, standard NWP resolutions of tens of kilometers are adequate to capture the CAT events.

Exposure to Volatile Organic Compounds and Loss of Pulmonary Function in the Elderly

ISEE-0180 Background: Volatile organic compounds (VOC) are reported to cause adverse effects on pulmonary function in occupationally exposed workers. However, evidence is lacking on the effect of exposure to ambient VOC on pulmonary function in the general population. We hypothesized that exposure to VOC results in oxidative stress and changes in pulmonary function, especially in the elderly population. Methods: A longitudinal panel study of 154 elderly people was performed at three different regions in South Korea. Repeated spirometric tests were performed on 8 different days. We measured the concentration of metabolites of VOC (Muconic acid, Mandelic acid, Hippuric acid, and Methylhippuric acid) and markers of oxidative stress (Malondialdehyde[MDA] and 8-hydroxydeoxyguanosin[8-OHdG]) from urine samples. A mixed linear regression model was used to evaluate the association between the environmental exposure and the outcome variables. Results: The mean age of the participants was 73.5 years old. We found significant association between the metabolites of VOC and at least one of the two markers of oxidative stress (P < 0.05). There were also significant associations between the markers of oxidative stress and pulmonary function tests such as forced expiratory volume in 1 second (FEV1), FEV1 as a percentage of FVC (FEV1/FVC), and forced expiratory flow between 25 and 75% of the FVC (FEF25–75) (P < 0.05). We found that the urinary levels of hippuric acid and methylhippuric acid were significantly associated with reduction of these pulmonary function parameters (P < 0.05). Conclusion: Exposure to ambient VOC in elderly people exacerbates systemic oxidative stress and thus exerts a harmful effect on pulmonary function.

Metabolomic Studies on Geographical Grapes and Their Wines Using1H NMR Analysis Coupled with Multivariate Statistics

Environmental vineyard conditions can affect the chemical composition or metabolites of grapes and their wines. Grapes grown in three different regions of South Korea were collected and separated into pulp, skin, and seed. The grapes were also vinified after crushing. (1)H NMR spectroscopy with pattern recognition (PR) methods was used to investigate the metabolic differences in pulp, skin, seed, and wines from the different regions. Discriminatory compounds among the grapes were Na, Ca, K, malate, citrate, threonine, alanine, proline, and trigonelline according to PR methods of principal component analysis (PCA) or partial least-squares discriminant analysis (PLS-DA). Grapes grown in regions with high sun exposure and low rainfall showed higher levels of sugar, proline, Na, and Ca together with lower levels of malate, citrate, alanine, threonine, and trigonelline than those grown in regions with relatively low sun exposure and high rainfall. Environmental effects were also observed in the complementary wines. This study demonstrates that (1)H NMR-based metabolomics coupled with multivariate statistical data sets can be useful for determining grape and wine quality.

Natural Occurrence of Aflatoxin B1 in Marketed Foods and Risk Estimates of Dietary Exposure in Koreans

Aflatoxin B1 (AFB1) is an unavoidable food contaminant. To evaluate the potential health risk of AFB1 to Koreans posed by food consumption, we determined the natural occurrence of AFB1 in food and estimated the excess risk for liver cancer through dietary exposure to AFB1. A total of 694 food samples collected from six different regions of South Korea were analyzed for their AFB1 content. One hundred four of the 694 samples were found to give positive enzyme-linked immunosorbent assay (ELISA) readings for AFB1 and were further investigated with high-performance liquid chromatography. Thirty-two samples, including 2 maize samples, 3 soybean products, 20 peanut samples, nut samples, and their products, and 7 spices, were found to be contaminated with AFB1 (4.6% incidence), up to 48.6 μgkg−1. The level of AFB1 contamination in 28 of the 32 food products was below 10 μgkg−1, which is the legal tolerance limit in Korea. From data on daily food consumption, the exposure dose of AFB1 was estimated to be 6.42 × 10−7 mg kg−1 body weight (bw) day−1. The major contributors to the dietary intake of AFB1 were soybean paste and soy sauce, which composed 91% of the total exposure to AFB1. The excess risk of liver cancer for those exposed to AFB1 through food intake was estimated to be 5.78 × 10−6 for hepatitis B–negative individuals and 1.48 × 10−4 for hepatitis B–positive individuals. These results suggest that special consideration is required to reduce the intake of AFB1 in hepatitis B–positive individuals.

Molecular phylogenetic analysis of human immunodeficiency virus type 1 strains obtained from Korean patients: env gene sequences.

303 HUMAN IMMUNODEFICIENCY VIRUS TYPE 1 subtypes have mainly been analyzed by nucleotide sequencing, by the DNA heteroduplex mobility assay, and by serotyping using synthetic peptides.5 Myers et al.6 have divided the subtypes into two groups, major (subtype A±J) and outlier (Group O), on the basis of the nucleotide sequences of the complete gag and env genes. These HIV-1 subtypes are generally confined to specific geographic locations. Because HIV-1 subtypes can be grouped on the basis of the nucleotide sequences of the V3 loop and its flanking regions C2±C3, analysis of the nucleotide sequences of these regions contributes to our understanding of the evolution and spread of HIV-1, in addition to providing data on prevention strategies for that population. Since the first case of HIV infection was reported in Korea in December 1985, the number of HIV-infected patients has increased annually and 647 cases of HIV infection have been reported as of March 31, 1997.7 Of the known cases of HIV infection, 37.7% are known to be infected through heterosexual contact abroad and the remainder are infected through in-country contact. To investigate the genetic diversity and epidemiological distribution of HIV-1 in Korea, we collected blood samples from 58 HIV-1-seropositive patients enrolled at the Center for AIDS Research (National Institute of Health [NIH], Seoul, Korea). The donors were from geographically different regions of South Korea. Of the subjects (whose sex ratio was 50:8, male:female), 23 patients were infected through heterosexual contact and 25 through homosexual contact. The remaining 10 patients were infected by blood transfusion or by using blood products. In the clinical aspects, the study subjects consisted of 21 patients with AIDS or AIDS related-complex and 37 with asymptomatic infection. Seven AIDS patients died during the course of the study. The clinical profile of each subject is presented in Table 1. HIV-1 DNA sequences encoding approximately 242 bp (nucleotides 6990±7234, HIVNL43 sequence) and 375 bp (nucleotides 6990±7367, HIVNL43 sequence) of the gp120 C2-toV3 region were amplified by nested PCR from uncultured peripheral blood mononuclear cells. The cDNAs were cloned into the pGEMT vector (Promega, Madison, WI) and an average of three clones from each sample were sequenced, except for samples KR4, KR10, KR11, KR15, KR16, and KR37. For the comparison of sequences of different size, the C2±V3 region (220 bp) in the 242-bp products was used for analysis, excluding the primer regions. The deduced amino acid sequences of the C2±V3 region of the env gene of HIV-1 from 58 Korean isolates and a consensus sequence derived from them are shown in Fig. 1. All of the isolates have cysteines at both ends of the V3 termini. At the crown of the V3 loop, eight different tetrameric sequences were found. GPGS and GPGR motifs were found in 45 (83%) isolates. Forty-four isolates among these, i.e., all except KR48, were clustered as subtype B. One remarkable finding is that a novel motif, RPRS, was found in three clones of KR45. This has never been reported before, and it belongs to subtype B. Other motifsÐ GPGQ (six cases), APGS (three cases), APGR, GPGG, and GPGKÐ were also found. All six cases with the GPGQ motif belonged to a non-B subtype. According to the Los Alamos Database, GPGQ is mainly found in subtype A, and also is distributed in subtypes E, C, F, B, and G.6 Phylogenetic analysis was carried out with nucleotide sequences from each representative clone of isolates by using parsimony and neighbor-joining methods included with the PHYLIP package.8 Phylogenetic analysis indicated that different clones in one patient never clustered as different subtypes (data not shown), and 51 of 58 isolates (88%) were clustered as subtype B (Fig. 2). Seven patients belonging to a non-B sub-