Generation of Salmonella ghost cells expressing fimbrial antigens of enterotoxigenic Escherichia coli and evaluation of their antigenicity in a murine model

Salmonella Typhimurium ghost cells expressing K88ab, K88ac, K99, and FasA fimbriae of enterotoxigenic Escherichia coli (ETEC) in their envelopes were constructed. The genes encoding the fimbriae were individually cloned into an expression plasmid, pMMP81, carrying the asd gene, which was subsequently electroporated into the Δasd S. Typhimurium mutant. Plasmid pJHLP99, carrying the phiX174 lysis gene E, was also subsequently electroporated into the Salmonella mutant. The presence of the individual fimbriae on the ghost cells was examined by Western blot analysis. Forty BALB/c mice were equally divided into 2 groups of 20 mice each. Group A mice were intramuscularly vaccinated with a mixture of the 4 ghost cells expressing the individual fimbriae. The group B mice were inoculated with sterile phosphate-buffered saline as a control. The antigen-specific serum IgG concentrations were significantly higher in group A than in group B from week 2 until week 6 after inoculation. In addition, the antigen-specific IgA concentrations in fecal samples were significantly higher in group A than in group B at week 2 after inoculation. A large difference between the groups in the number of antigen-specific IgA-secreting cells in the small intestine was observed by immunohistochemical study. Also, the splenic lymphocyte proliferative responses were significantly greater in group A than in the control mice. These results suggest that vaccination with our Salmonella ghost cells can induce both humoral and cell-mediated immune responses and that the increased number of antigen-specific IgA-secreting cells in the small intestine may be correlated with the elevated fecal IgA immune response.     

The Effects of Omega-3 Fatty Acid on Vitamin D Activation in Hemodialysis Patients: A Pilot Study

The high incidence of cardiovascular disease and vitamin D deficiency in chronic kidney disease patients is well known. Vitamin D activation by omega-3 fatty acid (FA) supplementation may explain the cardioprotective effects exerted by omega-3 FA. We hypothesized that omega-3 FA and 25-hydroxyvitamin D (25(OH)D) supplementation may increase 1,25-dihydroxyvitamin D (1,25(OH)₂D) levels compared to 25(OH)D supplementation alone in hemodialysis (HD) patients that have insufficient or deficient 25(OH)D levels. We enrolled patients that were treated for at least six months with 25(OH)D < 30 ng/mL ({"type":"clinical-trial","attrs":{"text":"NCT01596842","term_id":"NCT01596842"}}NCT01596842). Patients were randomized to treatment for 12 weeks with cholecalciferol supplemented with omega-3 FA or a placebo. Levels of 25(OH)D and 1,25(OH)₂D were measured after 12 weeks. The erythrocyte membrane FA contents were also measured. Levels of 25(OH)D were increased in both groups at 12 weeks compared to baseline. The 1,25(OH)₂D levels at 12 weeks compared to baseline showed a tendency to increase in the omega-3 FA group. The oleic acid and monounsaturated FA content decreased, while the omega-3 index increased in the omega-3 FA group. Omega-3 FA supplementation may be partly associated with vitamin D activation, although increased 25(OH)D levels caused by short-term cholecalciferol supplementation were not associated with vitamin D activation in HD patients.     

Re-examination of the standard cultivation practices of rice in response to climate change in Korea

The impact of climate change has been simulated or estimated to bring about yield decline and quality deterioration of rice in Korea, a temperate country. To cope with these negative impacts, here we propose likely changes in the standard cultivation practices of rice in consideration of the current information on the progress/prediction of climate change and related physiological aspects of rice. Shifting grain-filling period could be a promising choice to optimize temperature for rice grain-filling, a crucial growth stage to productivity, hence providing rice plants with sufficient duration and solar radiation for the period. This choice, however, shortens days to flowering by the additive combined effects of high temperature by delayed transplanting, temperature rise itself by climate change, and accelerated phase change of rice by high temperature and short day-length. These combined effects may delay the time of transplanting in a great extent, hence reducing biomass accumulation of rice before flowering. In these conditions, recovering decreased biomass production is the key concern for rice productivity. This includes raising healthy seedlings by omitting the covering process, dense planting, and nutrient management to enhance plant’s uptake activity. Current standard water management, especially mid-term drainage and intermittent irrigation, would have more importance in the future since they mitigate methane emission from the paddy. Field monitoring for weeds and pests would be an important first step to identify newly developing or thriving species for establishing subsequent controlling strategies. Earlier weed control should be emphasized through adjusting time of herbicide application.     

Enzymatic preparation of kaempferol from green tea seed and its antioxidant activity

Among the flavonols in green tea, kaempferol has many biological activities but kaempferol of plant origin is too expensive to be used in commercial products. Recently, we confirmed that green tea seed (GTS) contained a reasonable amount of kaempferol glycoside. After conducting structure analysis, two kaempferol glycosides were identified, kaempferol-3-O-[2-O-beta-D-galactopyranosyl-6-O-alpha-L-rhamnopyranosyl]-beta-D-glucopyranoside (compound 1) and kaempferol-3-O-[2-O-beta-D-xylopyranosyl-6-O-alpha-L-rhamnopyranosyl]-beta-D-glucopyranoside (compound 2), respectively. Also, a commercially useful method for kaempferol preparation was suggested by enzymatic hydrolysis using these two flavonoids. After several enzyme reactions were performed for the complete bioconversion of compounds 1 and 2 to kaempferol, we found that the optimum enzyme combination was reaction with beta-galactosidase and hesperidinase. Finally, we produced pure kaempferol with over 95% purity. We also compared the antioxidant effect of these two GTS flavonoids and its aglycone, kaempferol. Kaempferol is a more efficient scavenger of 1,1-diphenyl-2-picrylhydrazyl radicals and a better inhibitor of xanthine/xanthine oxidase than the two glycosides.     

Metabolite profiling of Angelica gigas from different geographical origins using 1H NMR and UPLC-MS analyses

Angelica gigas obtained from different geographical regions was characterized using (1)H nuclear magnetic resonance (NMR) spectroscopy and ultraperformance liquid chromatography-mass spectrometry (UPLC-MS) followed by multivariate data analyses. Principal component analysis (PCA) and orthogonal partial least-squares-discriminant analysis (OPLS-DA) score plots from (1)H NMR and UPLC-MS data sets showed a clear distinction among A. gigas from three different regions in Korea. The major metabolites that contributed to the discrimination factor were primary metabolites including acetate, choline, citrate, 1,3-dimethylurate, fumarate, glucose, histamine, lactose, malate, N-acetylglutamate, succinate, and valine and secondary metabolites including decursin, decursinol, nodakenin, marmesin, 7-hydroxy-6-(2R-hydroxy-3-methylbut-3-ethyl)coumarin in A. gigas roots. The results demonstrate that (1)H NMR and UPLC-MS-based metabolic profiling coupled with chemometric analysis can be used to discriminate the geographical origins of various herbal medicines and to identify primary and secondary metabolites responsible for discrimination.     

Antimicrobial Property of 2-Hydroxypropane-1,2,3-Tricarboxylic Acid Isolated from Citrus microcarpa Extract

This article described antimicrobial property and structure analysis of 2-hydroxypropane-1,2,3-tricarboxylic acid isolated from the crude extract of Citrus microcarpa. Presently, there was no report on compound from C. microcarpa that possessed antimicrobial property against fish pathogenic bacteria. Therefore, in this study, the bioactive principle in C. microcarpa extract was isolated using thin layer chromatography. It＇s structure was elucidated based on nuclear magnetic resonance （NMR） spectroscopic data, such as proton NMR （1HNMR）, correlation spectroscopy, carbon 13 NMR, and heteronuclear multiple bond correlation data. This study showed that the bioactive compound isolated from C. microcarpa was 2-hydroxypropane-1,2,3-tricarboxylic acid monohydrate. The minimum inhibitory concentration （MIC） values of crude C. microcarpa extract and its bioactive component, 2-hydroxypropane-1,2,3-tricarboxylic acid as well as commercially available synthetic 2-hydroxypropane-1,2,3-tricarboxylic acid, were determined against 18 isolates of Edwardsiella tarda and 7 bacterial reference strains, namely, Escherichia coli （ATCC 25922）, Citrobacter freundii （ATCC 8090）, Aeromonas hydrophila （ATCC 49140）, Pseudomonas aeruginosa （ATCC 35032）, Streptococcus agalatiae （ATCC 13813）, E. tarda （ATCC 15947）, and Yersinia enterocolitica （ATCC 23715）, using two-fold microdilution method. The MIC values for both the natural 2-hydroxypropane-1,2,3-tricarboxylic acid and the synthetic one were ranging from 15.6 to 62.5 mg mL-1, whereas that of the crude extract was ranging from 7.8 to 31.3 mg mL-1. These findings showed that both the crude extract and its bioactive component might have potential as antimicrobial agent for aquaculture use.     

Measurement of the distribution of site enhancements in surface-enhanced Raman scattering

On nanotextured noble-metal surfaces, surface-enhanced Raman scattering (SERS) is observed, where Raman scattering is enhanced by a factor, G, that is frequently about one million, but underlying the factor G is a broad distribution of local enhancement factors, eta. We have measured this distribution for benzenethiolate molecules on a 330-nanometer silver-coated nanosphere lattice using incident light of wavelength 532 nanometers. A series of laser pulses with increasing electric fields burned away molecules at sites with progressively decreasing electromagnetic enhancement factors. The enhancement distribution P(eta)deta was found to be a power law proportional to (eta)(-1.75), with minimum and maximum values of 2.8 x 10(4) and 4.1 x 10(10), respectively. The hottest sites (eta >10(9)) account for just 63 in 1,000,000 of the total but contribute 24% to the overall SERS intensity.     

The Fusarium graminearum genome reveals a link between localized polymorphism and pathogen specialization

We sequenced and annotated the genome of the filamentous fungus Fusarium graminearum, a major pathogen of cultivated cereals. Very few repetitive sequences were detected, and the process of repeat-induced point mutation, in which duplicated sequences are subject to extensive mutation, may partially account for the reduced repeat content and apparent low number of paralogous (ancestrally duplicated) genes. A second strain of F. graminearum contained more than 10,000 single-nucleotide polymorphisms, which were frequently located near telomeres and within other discrete chromosomal segments. Many highly polymorphic regions contained sets of genes implicated in plant-fungus interactions and were unusually divergent, with higher rates of recombination. These regions of genome innovation may result from selection due to interactions of F. graminearum with its plant hosts.