Relative Risk Prediction of Norovirus Incidence under Climate Change in Korea.

As incidences of food poisoning, especially norovirus-induced diarrhea, are associated with climate change, there is a need for an approach that can be used to predict the risks of such illnesses with high accuracy. In this paper, we predict the winter norovirus incidence rate in Korea compared to that of other diarrhea-causing viruses using a model based on B-spline added to logistic regression to estimate the long-term pattern of illness. We also develop a risk index based on the estimated probability of occurrence. Our probabilistic analysis shows that the risk of norovirus-related food poisoning in winter will remain stable or increase in Korea based on various Representative Concentration Pathway (RCP) scenarios. Our approach can be used to obtain an overview of the changes occurring in regional and seasonal norovirus patterns that can help assist in making appropriate policy decisions.

Enrichment Broth for the Detection of Campylobacter jejuni and Campylobacter coli in Fresh Produce and Poultry.

Although campylobacteriosis caused by Campylobacter jejuni and Campylobacter coli has been increasingly reported worldwide owing to the consumption of contaminated poultry and fresh produce, the current detection protocols are not selective enough to inhibit unspecific microbes other than these pathogens. Five antibiotics were separately added to Bolton broth, and the survival rates of 18 Campylobacter spp. and 79 non-Campylobacter spp. were evaluated. The survival rate of the non-Campylobacter spp. was the lowest in Bolton broth with rifampin (6.3%), followed by cefsulodin (12.7%), novobiocin (16.5%), and potassium tellurite and sulfamethozaxole (both 17.7%). Also the most effective concentration of rifampin was found to be 12.5 mg/L, which markedly inhibited non-Campylobacter strains while not affecting the survival of Campylobacter strains. After the Campylobacter spp. were enriched in Bolton broth supplemented with 12.5 mg/L rifampin (R-Bolton broth), CampyFood Agar (CFA) was found to be better in selectively isolating the pathogens in the enrichment broth than the International Organization for Standardization method of using modified charcoal cefoperazone deoxycholate agar (mCCDA) for this step. When applied to natural food samples-here, romaine lettuce, pepper, cherry tomato, Korean leek, and chicken-the R-Bolton broth-CFA combination decreased the number of false-positive results by 50.0, 4.2, 20.8, 50.0, and 94.4%, respectively, compared with the International Organization for Standardization method (Bolton broth-mCCDA combination). These results demonstrate that the combination of R-Bolton broth and CFA is more efficient in detecting C. jejuni and C. coli in poultry and fresh produce and thus should replace the Bolton broth-mCCDA combination.

Characterization of Bacillus amyloliquefaciens DA12 Showing Potent Antifungal Activity against Mycotoxigenic Fusarium Species.

In an attempt to develop a biological control agent against mycotoxigenic Fusarium species, we isolated Bacillus amyloliquefaciens strain DA12 from soil and explored its antimicrobial activities. DA12 was active against the growth of mycotoxigenic F. asiaticum, F. graminearum, F. proliferatum, and F. verticillioides both in vitro and in planta (maize). Further screening using dual culture extended the activity range of strain DA12 against other fungal pathogens including Botrytis cinerea, Colletotrichum coccodes, Endothia parasitica, Fusarium oxysporum, Raffaelea quercus-mongolicae, and Rhizoctonia solani. The butanol extract of the culture filtrate of B. amyloliquefaciens DA12 highly inhibited the germination of F. graminearum macroconidia with inhibition rate 83% at a concentration of 31.3 µg/ml and 100% at a concentration of 250 µg/ml. The antifungal metabolite from the butanol extract was identified as iturin A by thin layer chromatography-bioautography. In addition, volatile organic compounds produced by DA12 were able to inhibit mycelial growth of various phytopathogenic fungi. The volatile compounds were identified as 2-heptanone, 5-methyl heptanone and 6-methyl heptanone by gas chromatography-mass spectrometry (GC-MS) analysis. These results indicate that the antagonistic activity of Bacillus amyloliquefaciens DA12 was attributable to iturin A and volatile heptanones, and the strain could be used as a biocontrol agent to reduce the development of Fusarium diseases and mycotoxin contamination of crops.

Forecasting Spring Emergence of the Asian Corn Borer, Ostrinia furnacalis (Lepidoptera: Crambidae), Based on Postdiapause Development Rate.

This study was conducted to develop temperature-dependent postdiapause development models of overwintering larvae of the Asian corn borer, Ostrinia furnacalis Guenée (Lepidoptera: Crambidae), and to evaluate the models' forecasting accuracy using spring adult emergence data. Overwintering larvae were collected at three different times: 24 February (first), 23 March (second), and 25 April (third), 2005. The developmental periods of each collection colony were measured at eight constant temperatures, and those developmental rates were modeled with linear and nonlinear regression. One linear and three nonlinear models provided good fits of developmental rate to temperature across all colonies (r2 = 0.96-0.99). The distribution of development completion time was modeled with a Weibull equation that fit data from the second (r2 = 0.92) and third (r2 = 0.97) colonies better than the first (r2 = 0.87). A Lactin 2 model based on data from the first colony was statistically the best model to describe the relationship between temperature and the postdiapause development rate of O. furnacalis (r2adj = 0.99). However, validation results based on the field data showed that the Logan 6 model combined with the Weibull model (based on the second colony) was well describing spring adult emergence patterns up to 50% cumulative emergence date.

Correlations between the sequelae of stroke and physical activity in Korean adult stroke patients.

[Purpose] The present study investigated a wide range of stroke patients living in South Korea using the Korean Community Health Survey raw data to determine the correlation between stroke and physical activity. [Subjects and Methods] This study used raw data from the 2012 Korean Community Health Survey. The total number of participants was 228,921; of the 4,475 stroke patients who had been diagnosed by a medical doctor or an oriental medical doctor, the data for 4,460 patients, excluding 15 whose amount of physical activity was unclear, were used in the analysis. [Results] The amount of physical activity performed by patients who had sequelae was significantly lower than that performed by patients who no longer had sequelae. Similarly, for the type of sequelae, palsy in the arms and legs, facial palsy, communication disability, swallowing or eating disability, and visual disability were associated with lower physical activity. Furthermore, as the number of sequelae increased, patients performed significantly less physical activity. [Conclusion] The findings suggest that when decisions on national policies and budgets are made, methods for increasing the physical activity of patients with a history of stroke should be considered.

The effects of forced breathing exercise on the lumbar stabilization in chronic low back pain patients.

[Purpose] This study was conducted to investigate the effects of forced breathing exercise on the trunk functions of chronic low back pain patients. [Subjects and Methods] Twenty-four patients with chronic low back pain were randomly divided into groups of respiratory effort and trunk stabilization exercises. The exercises were performed for 45 minutes, 3 times per week for 6 weeks. Spinal stabilization was measured as the compensation of thesagittal angle joint in relation to the lumbar external load. [Results] After the intervention, the forced breathing and stabilization exercise groups showed a significant difference in lumbar spine stabilization between the first and second stress tests and the control group also showed a significant difference after the intervention. The M1 and M2 tests of lumbar spine stabilization revealed no significant differences between the groups. [Conclusion] The results of this research demonstrate that forced breathing exercise therapy is effective at improving the trunk stability and daily living activities of chronic low back pain patients.

Monitoring of Fasciola Species Contamination in Water Dropwort by cox1 Mitochondrial and ITS-2 rDNA Sequencing Analysis.

Fascioliasis, a food-borne trematode zoonosis, is a disease primarily in cattle and sheep and occasionally in humans. Water dropwort (Oenanthe javanica), an aquatic perennial herb, is a common second intermediate host of Fasciola, and the fresh stems and leaves are widely used as a seasoning in the Korean diet. However, no information regarding Fasciola species contamination in water dropwort is available. Here, we collected 500 samples of water dropwort in 3 areas in Korea during February and March 2015, and the water dropwort contamination of Fasciola species was monitored by DNA sequencing analysis of the Fasciola hepatica and Fasciola gigantica specific mitochondrial cytochrome c oxidase subunit 1 (cox1) and nuclear ribosomal internal transcribed spacer 2 (ITS-2). Among the 500 samples assessed, the presence of F. hepatica cox1 and 1TS-2 markers were detected in 2 samples, and F. hepatica contamination was confirmed by sequencing analysis. The nucleotide sequences of cox1 PCR products from the 2 F. hepatica-contaminated samples were 96.5% identical to the F. hepatica cox1 sequences in GenBank, whereas F. gigantica cox1 sequences were 46.8% similar with the sequence detected from the cox1 positive samples. However, F. gigantica cox1 and ITS-2 markers were not detected by PCR in the 500 samples of water dropwort. Collectively, in this survey of the water dropwort contamination with Fasciola species, very low prevalence of F. hepatica contamination was detected in the samples.

Fasciola hepatica in snails collected from water-dropwort fields using PCR.

Fasciola hepatica is a trematode that causes zoonosis mainly in cattle and sheep and occasionally in humans. Fascioliasis has been reported in Korea; however, determining F. hepatica infection in snails has not been done recently. Thus, using PCR, we evaluated the prevalence of F. hepatica infection in snails at 4 large water-dropwort fields. Among 349 examined snails, F. hepatica-specific internal transcribed space 1 (ITS-1) and/or ITS-2 markers were detected in 12 snails and confirmed using sequence analysis. Morphologically, 213 of 349 collected snails were dextral shelled, which is the same aperture as the lymnaeid snail, the vectorial host for F. hepatica. Among the 12 F. hepatica-infected snails, 6 were known first intermediate hosts in Korea (Lymnaea viridis and L. ollula) and the remaining 6 (Lymnaea sp.) were potentially a new first intermediate host in Korea. It has been shown that the overall prevalence of the snails contaminated with F. hepatica in water-dropwort fields was 3.4%; however, the prevalence varied among the fields. This is the first study to estimate the prevalence of F. hepatica infection using the vectorial capacity of the snails in Korea.

Comparison of Trichothecene Biosynthetic Gene Expression between Fusarium graminearum and Fusarium asiaticum.

Nivalenol (NIV) and deoxynivalenol (DON) are predominant Fusarium-producing mycotoxins found in grains, which are mainly produced by Fusarium asiaticum and F. graminearum. NIV is found in most of cereals grown in Korea, but the genetic basis for NIV production by F. asiaticum has not been extensively explored. In this study, 12 genes belonging to the trichothecene biosynthetic gene cluster were compared at the transcriptional level between two NIV-producing F. asiaticum and four DON-producing F. graminearum strains. Chemical analysis revealed that time-course toxin production patterns over 14 days did not differ between NIV and DON strains, excluding F. asiaticum R308, which was a low NIV producer. Both quantitative real-time polymerase chain reaction and Northern analysis revealed that the majority of TRI gene transcripts peaked at day 2 in both NIV and DON producers, which is 2 days earlier than trichothecene accumulation in liquid medium. Comparison of the gene expression profiles identified an NIV-specific pattern in two transcription factor-encoding TRI genes (TRI6 and TRI10) and TRI101, which showed two gene expression peaks during both the early and late incubation periods. In addition, the amount of trichothecenes produced by both DON and NIV producers were correlated with the expression levels of TRI genes, regardless of the trichothecene chemotypes. Therefore, the reduced production of NIV by R308 compared to NIV or DON by the other strains may be attributable to the significantly lower expression levels of the TRI genes, which showed early expression patterns.

Effects of galvanic vestibular stimulation on visual memory recall and EEG.

[Purpose] This study aimed to examine the effects of galvanic vestibular stimulation (GVS) on visual memory recall and EEG. [Subjects and Methods] In the present study, 42 adults were selected and divided equally into two groups of 21 adults, the GVS group and the Sham group. The error rate was calculated as a percentage based on the total number of errors in the answers to 24 questions after stimulation, while the reaction time was measured in intervals between the time the questions were asked and the time it took the subjects to answer the questions. EEG data were obtained by attaching electrodes to the Fz, Cz, and Pz points during the question and answer phase. [Results] The error rate showed statistically significant differences in the interaction involving the time of response and group. The reaction time showed no statistically significant differences in the interaction involving the time of response and group. When relative band power parameters were analyzed, alpha waves showed no statistically significant differences in the interaction involving the time of response and group, but only the Fz area of beta waves showed statistically significant differences in the interaction involving the time of response and group. [Conclusion] GVS may improve visual memory recall in relation to a flower, a person, an animal, or a building.

Gene-related strain variation of Staphylococcus aureus for homologous resistance response to acid stress.

This study investigated the effect of adaptation of Staphylococcus aureus strains to the acidic condition of tomato in response to environmental stresses, such as heat and acid. S. aureus ATCC 13565, ATCC 14458, ATCC 23235, ATCC 27664, and NCCP10826 habituated in tomato extract at 35°C for 24 h were inoculated in tryptic soy broth. The culture suspensions were then subjected to heat challenge or acid challenge at 60°C and pH 3.0, respectively, for 60 min. In addition, transcriptional analysis using quantitative real-time PCR was performed to evaluate the expression level of acid-shock genes, such as clpB, zwf, nuoF, and gnd, from five S. aureus strains after the acid habituation of strains in tomato at 35°C for 15 min and 60 min in comparison with that of the nonhabituated strains. In comparison with the nonhabituated strains, the five tomato-habituated S. aureus strains did not show cross protection to heat, but tomato-habituated S. aureus ATCC 23235 showed acid resistance. In quantitative real-time-PCR analysis, the relative expression levels of acid-shock genes (clpB, zwf, nuoF, and gnd) were increased the most in S. aureus ATCC 23235 after 60 min of tomato habituation, but there was little difference in the expression levels among the five S. aureus strains after 15 min of tomato habituation. These results indicate that the variation of acid resistance of S. aureus is related to the expression of acid-shock genes during acid habituation.