Pharmacodynamics of amoxicillin against field isolates of Streptococcus parauberis from olive flounder (Paralichthys olivaceus)

Olive flounder is the most important species for the Northeast Asian fish farming industry. However, this species is substantially affected by multiple infectious agents, including Streptococcus parauberis. Evaluation of antibiotics before their application is critical to treat infections and prevent drug resistance. Therefore, in this study, the pharmacodynamics of amoxicillin (AMX) and other antimicrobials against the planktonic‐ and biofilm‐forming bacteria were assessed. The minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC) and Time–kill curve assay were analysed using micro‐dilution method. The minimum biofilm eradicating concentration (MBEC) was determined using the Calgary Biofilm device. The effects of temperature, pH, hardness and salinity were detected for both planktonic‐ and biofilm‐forming bacteria. The MIC of AMX ranged from 0.015 to 2 μg/ml, whereas that of cephalexin (CEP), enrofloxacin (ENR) and oxytetracycline (OTC) ranged from 0.125 to 256, 0.125 to >512 and 0.25 to >512 μg/ml respectively. No bacteria were resistant against AMX, while the percentage of resistance to CEP, OTC and ENR were 68.7%, 52.6% and 11.1% respectively. The IC₅₀ of AMX, CEP, ENR and OTC was 0.03, 0.091, 0.015 and 0.213 μg/ml respectively. The MBEC of amoxicillin against S. parauberis ranged from 0.5 to 16 μg/ml. Higher rates of bacterial growth were obtained at 30°C, pH = 8 and salinity of 7.5–10 ppt. The hardness of the media suppressed the bacterial growth. In conclusion, AMX was found to be effective against both the planktonic and the biofilm forms of the prominent fish pathogen, S. parauberis.     

Efficacy of a novel virulence gene-deleted Salmonella Typhimurium vaccine for protection against Salmonella infections in growing piglets

We have previously developed a novel attenuated Salmonella Typhimurium (S. Typhimurium) ΔcpxR Δlon vaccine. This study was carried out to examine whether this vaccine could effectively protect growing piglets against Salmonella infection. Attenuated S. Typhimurium secreting the B subunit of Escherichia coli heat-labile enterotoxin was also used as a mucosal adjuvant. Pregnant sows in groups A and B were primed and boosted with the vaccine and mucosal adjuvant, whereas sows in groups C, D and E received PBS. Piglets in groups A and C were intramuscularly primed with formalin-inactivated vaccine and orally boosted with live vaccine, while piglets in groups B, D and E received PBS. Piglets in groups A, B, C, and D were challenged with a wild type virulent S. Typhimurium at the 11th weeks of age. Colostrum sIgA and IgG titers in vaccinated groups A and B sows were approximately 50 and 40 times higher than those of non-vaccinated groups C, D and E sows (P < 0.001). Serum IgG titers of group A piglets were also significantly higher than those of groups D and E piglets during the study (P < 0.001). Furthermore, no clinical signs were observed in group A piglets during the entire experimental period after the challenge, while diarrhea was observed in many of the piglets in groups B, C, and D. No Salmonella was isolated from fecal samples of the groups A and C piglets on day 14 after challenge, whereas the challenge strain was isolated from several piglets in groups B and D. These results indicate that vaccination of the piglets with the vaccine and mucosal adjuvant in addition to vaccination of their sows induced effective protection against Salmonella infections in the growing piglets.     

A cross-cultural comparison of image perception and preferences for cotton fabrics between Korea and the United States

The purpose of this research was to perform an international comparison of image perception and preferences for cotton fabrics, specifically examining the inter-cultural differences that exist between Koreans and Americans. Respondents were asked to rate 55 different fabrics, produced in Korea, relative to eight different characterizations: feminine, masculine, casual, classic, new, old, ambiguous and orderly. Then they were asked to rate their level of preference for each fabric, using 7-point scales. Both Koreans and Americans evaluated thin and soft fabrics with pale colors high relative to feminine image and evaluated slightly thick, coarse and stiff fabrics with low chromatics high relative to masculine image. However, Koreans tended to categorize fabrics as feminine or masculine using color characteristics, while Americans tended to use surface characteristics. For the casual image, Denim and Chambray were rated highly, both in Korea and in the US. There were no fabrics which both countries rated highly for the classic image. New image was rated significantly above average in Korea, but average in the US. The old image perceptions fell below average in both countries. Most fabrics were evaluated above average with respect to being orderly, but fell below the average for ambiguous image, both in Korea and the US. Koreans showed higher preferences for the chosen fabrics than Americans, but the preference tendencies were similar in the two countries.     

Tensile,Thermal, and Electrical Conductivity Properties of Carbon Fiber Reinforced Composites Using Itaconic Acid Based Dispersants

We prepared itaconic acid based dispersants (IBDs) by the copolymerization of itaconic acid with acrylic acid, acrylamide, or vinyl sulfonic acid, and compared the efficacy of the IBDs on carbon fiber (CF) dispersion in a water-based system, against that of sodium dodecyl sulphate (SDS) which is widely used as a dispersing agent. The procedure to fabricate nonwoven CF (NCF)/PP composites using IBDs includes the following steps: the synthesis of IBDs, the dispersion of CFs in water by the IBDs, the formation of a NCF, and hot pressing of NCF with polypropylene (PP) layer. We determined the tensile, thermal properties, and the electrical conductivity of non-woven CF/PP composites. It was found that using IBDs as a CF dispersing agent led to the CF/PP composites having better tensile, thermal, and electrical properties, as compared to when SDS was used as a dispersing agent.     

Identification of syn- and anti-anethole-2,3-epoxides in the metabolism of trans-anethole by the newly isolated bacterium Pseudomonas putida JYR-1

Bacterial strain JYR-1, which utilizes high concentrations (up to 100 mM) of trans-anethole as the sole source of carbon and energy, was isolated from soil. It grew to OD(600)(nm) = 2.6 with a doubling time of 8 h when grown on 20 mM trans-anethole. Strain JYR-1 was identified as Pseudomonas putida based on the partial gene sequence of its 16S rDNA. Elution profiles of culture extracts were examined by high-performance liquid chromatography and showed that four metabolites were produced from the bacterial culture containing trans-anethole that were not detected in control experiments. LC-MS analysis showed molecular weights of 138.2, 164.5, 164.3, and 152.3. The metabolites with molecular weights at 152.3 and 138.2 were confirmed to be p-anisic acid and p-hydroxybenzoic acid, respectively, when compared with HPLC retention times and molecular weights of authentic compounds. The metabolites with molecular weights at 164.5 and 164.3 were further analyzed by NMR and were proved to be stereoisomer syn- and anti-anethole epoxides. Therefore, strain JYR-1 most likely initiates the metabolism of trans-anethole through the formation of epoxides on the propene group of the compound.     

A new on‐site detection method for Bursaphelenchus xylophilus in infected pine trees

The pinewood nematode (PWN), Bursaphelenchus xylophilus, is the causal agent of pine wilt disease (PWD), which is a major problem in East Asia and West Europe. Quick identification of PWN is needed to prevent the dispersal of PWD to healthy forests. Various detection methods of PWN have been developed using anatomical characters and molecular markers. These methods are not suitable for rapid diagnosis because it is difficult to distinguish B. xylophilus from the non‐pathogenic species Bursaphelenchus mucronatus based on morphological characters without expertise in nematode taxonomy and most PCR or isothermal amplification detection methods require time‐consuming processes. In this study, we developed an on‐site PWN detection method using a recombinase polymerase amplification (RPA) assay with a novel extraction buffer (DAP buffer). This new PWN detection method is able to extract genomic DNA from PWN in pinewood by simple buffer consisting of sodium hydrate, polyethylene glycol 200 and dimethyl sulfoxide in 10 min without using the experimental devices and able to distinguish between B. xylophilus and other Bursaphelenchus spp. by amplifying the species‐specific 5S rDNA fragment of B. xylophilus in 10 min. Taken together, our protocol can obtain the result for the detection of PWN in pine tree samples within 30 min. This result suggests that RPA/DAP assay is much faster, easier and cheaper than the conventional methods for detecting PWN.     

Antibacterial effect of Phellinus linteus against methicillin-resistant Staphylococcus aureus

Methanol extract and its fractions (CHCl3, n-BuOH and H2O) of the fruit body of Phellinus linteus mushroom were investigated for antibacterial activity against methicillin-resistant Staphylococcus aureus. The n-BuOH fraction showed a good antibacterial activity (MIC, 63-125 microg/ml) against all tested strains.     

Analysis of four 5-nitroimidazoles and their corresponding hydroxylated metabolites in egg, processed egg, and chicken meat by isotope dilution liquid chromatography tandem mass spectrometry

An isotope dilution liquid chromatography-electrospray ionization-tandem mass spectrometry method is presented for the simultaneous analysis of several 5-nitroimidazole-based veterinary drugs, which are dimetridazole (DMZ), ronidazole (RNZ), metronidazole (MNZ), ipronidazole (IPZ), and their hydroxylated metabolites (DMZOH, MNZOH, and IPZOH), in egg (fresh egg, whole egg powder, and egg yolk powder) and chicken meat. Data acquisition was achieved by applying multiple reaction monitoring, and quantitation was performed by means of five deuterated internal standards (ISs), namely, DMZ-d3, RNZ-d3, IPZ-d3, DMZOH-d3, and IPZOH-d3, whereas MNZ and MNZOH were quantitated using DMZOH-d3. At the lowest fortification levels (i.e., 0.5 microg/kg for fresh egg and chicken meat and 1.0 microg/kg for other egg-based matrices) and for compounds having their own corresponding deuterated analogue used as an IS, acceptable performance data were obtained (corrected recoveries, 88-111%; decision limits, 0.07-0.36 microg/kg; detection capabilities, 0.11-0.60 microg/kg; and within-lab precision, < or = 15%). The method failed to give acceptable quantitative results for MNZ and MNZOH due to the unavailability of the corresponding deuterated ISs. Nevertheless, a reliable identification of these two analytes at levels < or = 1 microg/kg was still feasible.     

Sphingomonas sp. strain SB5 degrades carbofuran to a new metabolite by hydrolysis at the furanyl ring

Microorganisms capable of degrading carbofuran were isolated from soils and examined for the degradation of this pesticide at ring structure. An isolate that could degrade carbofuran and carbofuran-7-phenol was selected for further studies. The 16S rRNA analysis results showed that the isolate belongs to the genus of Sphingomonas, close to dioxin and dicamba degraders, and is named Sphingomonas sp. SB5. SB5 did not show any similarity of 16S rRNA to known carbofuran degraders. When time-course degradation of carbofuran by SB5 was examined by solvent extraction combined with liquid chromatographic analysis, almost complete disappearance of carbofuran was observed within 12 h, giving several accumulative metabolites. Bacterial cultures incubated with carbofuran-7-phenol suggested that the accumulated metabolites were derived from carbofuran-7-phenol. The control without SB5 and kanamycin-treated SB5 did not show any metabolite, suggesting a biological involvement in the degradation of carbofuran. GC/MS and LC/MS analyses identified 2-hydroxy-3-(3-methylpropan-2-ol) phenol as one of the accumulated metabolites, suggesting that the strain SB5 could degrade carbofuran-7-phenol by hydrolysis at the furanyl ring. This is the first report to identify 2-hydroxy-3-(3-methylpropan-2-ol) phenol as a new product derived biologically from carbofuran-7-phenol.     

Effect of buckwheat extract on the antioxidant activity of lipid in mouse brain and its structural change during in vitro human digestion

This study was conducted to investigate the effects of buckwheat ( Fagopyrum esculentum Moench cv. Yangjul No. 2) extract on the antioxidant activity of lipids in mouse brain and the structural change during in vitro human digestion. Buckwheat was collected from a wild farm and extracted with water. The buckwheat extracts were then passed through an in vitro human digestion model that simulated the composition of the mouth, stomach, and small intestine juice. The results confirmed that the main phenolics of buckwheat extract were rutin, quercitrin, and quercetin. The rutin content increased with digestion of the buckwheat (from 48.82 to 96.34 μg/g) and rutin standard samples (from 92.76 to 556.56 μg/g). Antioxidant activity was more strongly influenced by in vitro human digestion of both buckwheat and rutin standard. After digestion by the small intestine, the antioxidant activity values were dramatically increased (from 5.06 to 87.82%), whereas the antioxidant activity was not influenced by digestion in the stomach for both buckwheat extract and rutin standard. Inhibition of lipid oxidation of buckwheat in mouse brain lipids increased after digestion in the stomach for both buckwheat extract and the rutin standard. The major finding of this study was that in vitro human digestion may be an important modulator of the antioxidant capacity of buckwheat and that this may be because in vitro human digestion increased the antioxidative activity via an increase in antioxidants such as rutin and quercetin.