An understanding of the geographic distribution of highly pathogenic avian influenza (HPAI) is essential to assessing and managing the risk of introduction of HPAI virus (HPAIV). However, to date, local spatial clustering patterns of HPAI outbreaks in Korea has not been explicitly investigated. We compiled HPAI outbreak data (n=622 cases) from December 2003 to February 2016. Each reported case was geocoded and linked to a digital map of Korea according to its onset location using the geographic information system (GIS). Kernel density estimation was used to explore global patterns of the HPAI outbreaks. We also applied the Getis-Ord G local spatial statistic to identify significant hot spots of high and low abundance by calculating Z-scores. Hot spot analysis revealed that HPAI cases are likely to be distinct clusters of HPAI outbreaks, with the highest risk being in the southwest of the country, specifically in Jeonnam and Jeonbuk provinces, where there are high density poultry populations. More than 16 Si-Gun-Gu (administrative province unit with bandwidth of 30 km) were involved in these high risk areas, indicating that there is likely to be a spatial heterogeneity of HPAI outbreaks within the country. Because of the existence of apparent hot spots, particularly in western regions, along with the increased number of migratory birds in these areas, Korea is at high risk of HPAIV introduction. Taking this challenge into consideration, preemptive and effective targeted surveillance programs for wild birds and poultry farms are highly recommended. Future research should look at the risk factors related to the socio-economic, human and natural environments and the poultry production systems to explain the spatial heterogeneity of HPAI outbreaks.
Oxidative stress is one of common cause of fatty changes in the liver. Antioxidant capacity was confirmed in various vegetables including black radish (Raphanus sativus L. var niger). Fermentation of vegetables using Lactobacillus plantarum has been known to generate bioactive components. This study was conducted to determine if fermented black radish (FBR) ameliorates oxidative liver injury induced by CCl4 in rats. To accomplish this, FBR (250 and 500 mg/ kg) was orally administered to rats for 7 consecutive days, single CCl4 (1.5 mL/kg) treatment or no treatment orally. Serum chemistry at 24 hours after CCl4 injury showed that FBR (500 mg/kg) significantly reduced the level of both alanine aminotransferase and aspartate aminotransferase in CCl4 exposed rats. Moreover, FBR treatment significantly increased radical-scavenging effects in livers with the reduction of lipid peroxidation in CCl4 exposed rats. Histopathologic findings including Kupffer cell activation in the liver of each group matched those of serum chemistry. Collectively, black radish, through fermentation, exerts hepatoprotective capacity in CCl4 induced liver injury in rats through anti-oxidation.
Turmeric is known for its ability to enhance immunity via anti-inflammatory and anti-oxidant effects. Salmonella enterica species contain a large number of pathogenic serotypes that are adapted to a broad range of vertebrate hosts. Our previous study revealed that bioprocessed polysaccharides from the liquid culture Lentinus edodes fungal mycelia containing turmeric (BPP-turmeric) is able to alter chicken macrophage responses and increases chick survival against Salmonella enterica infection. In this study, we examined the immunomodulatory effects of BPP-turmeric on the porcine macrophage 3D4/31 cell line infected with Salmonella enterica subsp. enterica serovar Choleraesuis (S. Choleraesuis) or S. Enteritidis. Our experimental analyses demonstrated that BPP-turmeric (i) does not alter phagocytic and killing activity of 3D4/31 against either Salmonella serotypes, but that it (ii) represses mRNA transcription of interleukin (IL)-6, IL-8, and tumor necrosis factor α in response to Salmonella infection. Collectively, these results imply that BPP-turmeric has an immunomodulatory effect that represses pro-inflammatory cytokine expression in porcine macrophages, suggesting that it may protect swine from salmonellosis via controlling Salmonella-induced hyperinflammation.
Colorectal cancer (CRC) is the third most prevalent cancer in the world, and heme iron is known to promote the CRC in an animal model. This study was conducted to investigate the effects of ascorbic acid in the presence of hemin on the formation of pre-neoplastic lesions induced by azoxymethane (AOM)/disodium sulfate (DSS) in mice. After acclimation for 1 week, five-week old mice received three s.c. injections (0-2 weeks of the experiment) of AOM [10 mg/kg body weight (BW)] weekly and were treated with 2% DSS in drinking water for the next week to induce aberrant crypt foci (ACF). All animals were fed the AIN-76A purified rodent diet for experimental period of 6 weeks. Experimental groups were then divided into three groups: carboxymethylcellulose (CMC) alone (control), CMC + Hemin, CMC + Hemin + ascorbic acid (AA). The CMC was used as a solvent for hemin. The daily doses were 534 mg/kg BW hemin and 246 mg/kg BW ascorbic acid administered orally. After the colonic mucosa were stained with methylene blue, aberrant crypt foci (ACF), aberrant crypt (AC) and polyps were counted. Lipid peroxidation in liver was evaluated by the thiobarbituric acid-reactive substances (TBARS) assay. The numbers of ACF, AC and large ACF (≥4 AC/ACF) per colon increased in the hemin group compared to the control group, while they decreased significantly in the hemin + ascorbic acid group compared to the control group or hemin group (p<0.01). The number of polyps/colon in the hemin + AA group was significantly decreased compared to the hemin group (p<0.05). In the liver, the TBARS value of the hemin group was significantly higher than that of the control group (p<0.01). Additionally, the TBARS value of the hemin + AA group decreased slightly compared to that of the hemin group. Taken together, these results suggest that hemin can promote colon carcinogenesis in a mouse model and that ascorbic acid has a protective effect against hemin-promoted colon carcinogenesis.
Chlorine dioxide gas is a relatively new sanitizer in the food industry that has more accessibility than its aqueous form. Depending on the method by which ClO2 gas is generated, there can be byproducts like chlorite and chlorate ions, which can decrease its disinfectant effect and purity. Recently, new technology that generates chlorine dioxide without using chlorine gas has been developed to remove those defects. This new electrochemical method generates gaseous chlorine dioxide from aqueous sodium chlorite (NaClO2). The present study was conducted to evaluate the effects of ClO2 gas generated by an electrochemical method against foodborne microorganisms. To accomplish this, ClO2 gas at different concentrations (1, 5, 10 and 20 ppm) was applied to E. coli and S. Typhimurium for different exposure times (1, 5, 10, 15 and 20 min) under room temperature conditions at <40% relative humidity. The results revealed ClO2 gas was highly effective for the inactivation of E. coli and S. Typhimurium and showed a reduction in populations of over 5 log CFU/ml under ambient conditions with low relative humidity (30–40%). In conclusion, ClO2 gas treatment is highly applicable to control of foodborne pathogens.
Induced pluripotent stem cells (iPSCs) can be generated from adult cells. Somatic cells can be reprogrammed to form iPSCs by overexpressing transcription factors such as Oct4, Sox2, cMyc, and Klf4. To maintain undifferentiated state of iPSCs in vitro, cells have traditionally been maintained on mouse embryonic fibroblast feeders and passaged by enzymatic or mechanical dissociation methods. In this study, we compared the morphology and pluripotency of porcine iPSCs (piPSCs) after subsequent passaging using enzymatic and mechanical dissociation methods. Enzymatically and mechanically passaged piPSCs showed embryonic stem cell-like morphologies with compact cell adhesion and clear colony borders. In addition, alkaline phosphatase staining was positive for both enzymatically and mechanically passaged piPSCs. However, visual observation revealed that some colonies of enzymatically passaged piPSCs were spontaneously differentiated more than those of piPSCs mechanically passaged from 5 passage. Quantitative real-time RT-PCR demonstrated that enzymatically and mechanically passaged piPSCs expressed pluripotent genes such as Oct4, Sox2 and Nanog well at early passage. Immunofluorescent staining also confirmed that pluripotent markers such as Oct4, Sox2, and Nanog were positively expressed at early passage. However, expression levels of pluripotent genes in mechanically passaged piPSCs were also higher than those in enzymatically passaged piPSCs at early passage. Collectively, we found that mechanical passage method was better than enzymatic passage in terms of morphology and pluripotency of piPSCs at early passage. Further studies are needed to compare these dissociation methods with those obtained after more passages of piPSCs.
The purpose of this study is to set the method condition of the DPRA in Korea throughout reproducibility study. We conducted intra-lab (triplicate) and inter-lab (three labs of CRI, KTR and CU) validation using 20 chemicals (10 chemicals for the proficiency test listed in the OECD test guideline 442C and an additional 10 more chemicals from reference papers). The data from all three labs met the acceptance criteria. Upon intra-lab validation, two positive chemicals out of 20 total chemicals showed false negative, and one negative chemical showed false positive. In inter-lab validation of three labs, the sensitivity data were 83, 83 and 88% each, and the specificity data was 100, 100 and 88% each. So the accuracy of the three labs was equal to 90%. During these studies, we also checked and improved various limitations that arose. Taken together, the results indicated that the DPRA proposed by OECD test guideline 442C is expected to become a well-established method under Korean GLP applied system.
In this paper, a mathematical model of regionalization based on graph theory to investigate the patterns induced by movements of livestock vehicles in cities under outbreaks of highly pathogenic avian influenza (HPAI) is proposed. We then compare the results of simulation from the regionalization model to actual HPAI outbreaks in 2016/2017 to evaluate the validity of the model. Specifically, we (1) configured a complex network structure with analytic tools and properties in graph theory to abstract the paths among farms and livestock facilities; (2) employed statistical methods to estimate the possibility of propagation between two clusters; (3) applied the developed method to an actual HPAI outbreak in Korea in 2016 and conducted a simulation to determine if the proposed modeling for regionalization is an effective prediction measure. The clustered regions proposed by the simulation correctly reflected the regional clustering of actual cases, while simultaneously contain the cities exposed to potential damage when separated. Based on these findings, we conclude that our proposed regionalization model is suitable for making policy judgments to establish a preemptive biosecurity system.
Staphylococcus (S.) aureus is commonly found on the skin and mucous membranes of animals. Moreover, some isolates producing staphylococcal enterotoxins (SE) are also responsible for food poisoning. This study was conducted to explore the prevalence of S. aureus enterotoxin from slaughtered pigs and cattle. A total of 202 carcass swabs were collected from slaughterhouses: 102 samples were taken from slaughtered pigs and 100 were taken from cattle, respectively. Among them, 16 (7.9%) from slaughtered pigs were found to contain S. aureus, while S. aureus was not isolated from any of the slaughtered cattle samples. Additionally, six (37.5%) of the S. aureus isolates contained genes that encode staphylococcal enterotoxin type A. Therefore, it is necessary to investigate the management of food-borne pathogens based on differences in the process by which pigs and cattle are slaughtered.
The ability of antimicrobial resistant Salmonella strains to cause invasive disease can be attributed to various virulence genes. In this study, the virulence genes located in SPI-1, SPI-2, SPI-5, SPI-11 were found in all antimicrobial-resistant Salmonella isolates. This suggests that these genes play important roles in Salmonella invasion, growth, or survival in the host. The association between the presence of virulence genes and antimicrobial resistance was assessed using the Spearman’s correlation coefficient, and there is a positive association between the gatC, tcfA, hylE, spiA, pagC, msgA, invA, sipB, prgH, spaN, orgA, tolC, iroN, sitC, lpfC, and sopB genes, and resistance to CF, NA and S. This suggests that the association between antimicrobial agents and virulence genes has been shown to vary with the types of antibiotics that are commonly used in different countries. These different associations can be explained by the mechanisms underlying pathogenicity and the acquisition of resistance genes by Salmonella.