Field Evaluation of the Bacterial Volatile Derivative 3-Pentanol in Priming for Induced Resistance in Pepper

Plants are defended from attack by emission of volatile organic compounds (VOCs) that can act directly against pathogens and herbivores or indirectly by recruiting natural enemies of herbivores. However, microbial VOC have been less investigated as potential triggers of plant systemic defense responses against pathogens in the field. Bacillus amyloliquefaciens strain IN937a, a plant growth-promoting rhizobacterium that colonizes plant tissues, stimulates induced systemic resistance (ISR) via its emission of VOCs. We investigated the ISR capacity of VOCs and derivatives collected from strain IN937a against bacterial spot disease caused by Xanthomonas axonopodis pv. vesicatoria in pepper. Of 15 bacterial VOCs and their derivatives, 3-pentanol, which is a C8 amyl alcohol reported to be a component of sex pheromones in insects, was selected for further investigation. Pathogens were infiltrated into pepper leaves 10, 20, 30, and 40 days after treatment and transplantation to the field. Disease severity was assessed 7 days after transplantation. Treatment with 3-pentanol significantly reduced disease severity caused by X. axonopodis and naturally occurring Cucumber mosaic virus in field trials over 2 years. We used quantitative real-time polymerase chain analysis to examine Pathogenesis-Related genes associated with salicylic acid (SA), jasmonic acid (JA), and ethylene defense signaling. The expression of Capsicum annuum Pathogenesis-Related protein 1 (CaPR1), CaPR2, and Ca protease inhibitor2 (CaPIN2) increased in field-grown pepper plants treated with 3-pentanol. Taken together, our results show that 3-pentanol triggers induced resistance by priming SA and JA signaling in pepper under field conditions.     

Efficient fault diagnosis method of PEMFC thermal management system for various current densities

The temperature of a fuel cell has a considerable impact on the saturation of a membrane, electrochemical reaction speed, and durability. So thermal management is considered one of the critical issues in polymer electrolyte membrane fuel cells. Therefore, the reliability of the thermal management system is also crucial for the performance and durability of a fuel cell system. In this work, a methodology for component-level fault diagnosis of polymer electrolyte membrane fuel cell thermal management system for various current densities is proposed. Specifically, this study suggests fault diagnosis using limited data, based on an experimental approach. Normal and five component-level fault states are diagnosed with a support vector machine model using temperature, pressure, and fan control signal data. The effects of training data at different operating current densities on fault diagnosis are analyzed. The effects of data preprocessing method are investigated, and the cause of misdiagnosis is analyzed. On this basis, diagnosis results show that the proposed methodology can realize efficient component-level fault diagnosis using limited data. The diagnosis accuracy is over 92% when the residual basis scaling method is used, and data at the highest operating current density is used to train the support vector machine.     

Functional characterization of purified pear protease and its proteolytic activities with casein and myofibrillar proteins

This study was performed to characterize pear protease proteolytic activity and investigate the use of pear protease as a meat tenderizer. Pear protease was purified and stabilized by 5% dextrin during lyophilization (dry) or concentration (liquid). Pear protease was further characterized with respect to pH, thermodynamics, and enzyme kinetics. Pear protease was stable at a pH range of 5-8 with an optimum pH of 6.5. From Arrhenius plots, liquid protease showed higher temperature dependency (23.49 kJ/mol) than dry protease (18.62 kJ/mol) due to its higher activation energy. The kcat/Km, catalytic efficiency of enzyme, was similar with 2.9 and 2.7 µM/min with dry and liquid proteases. Pear protease was evaluated for its proteolytic activities with casein and beef myofibrillar proteins by individually and combination with fig and kiwifruit proteases. These result indicated that pear and kiwifruit proteases could be complementary to be a desirable product for meat tenderization.     

Identification of cellulolytic bacteria associated with tunic softness syndrome in the sea squirt, Halocynthia roretzi

The edible ascidian, sea squirt Halocynthia roretzi (Drasche) is marine invertebrate that is a valuable source of foods and bioactive compounds. A severe disease of the sea squirt characterized by degeneration of tunic fibers formed of bundled cellulose microfibrils has occurred. We hypothesized that bacteria lyse the cellulose fibril structure, cellulase activity may be a causative agent of the disease. Among the bacteria isolated from diseased sea squirt, Pseudoalteromonas sp. NO3 had cellulase activity based on a Congo red overlay assay and starch-reducing activity. Sea squirts exhibited 40–100% cumulative mortality after injection with Pseudoalteromonas sp. NO3 using doses of 2×10⁶?2×10⁸ colony forming unit (CFU)/individual. Dead sea squirts possess thinner and ruptured tunics, which were similar to natural outbreaks. These results suggest that Pseudoalteromonas sp. NO3 possessing cellulase activity is one of the causes of tunic softness syndrome in sea squirt.     

Development of an Automated Method for Folin‐Ciocalteu Total Phenolic Assay in Artichoke Extracts

Abstract: We developed a system to run the Folin‐Ciocalteu (F‐C) total phenolic assay, in artichoke extract samples, which is fully automatic, consistent, and fast. The system uses 2 high performance liquid chromatography (HPLC) pumps, an autosampler, a column heater, a UV/Vis detector, and a data collection system. To test the system, a pump delivered 10‐fold diluted F‐C reagent solution at a rate of 0.7 mL/min, and 0.4 g/mL sodium carbonate at a rate of 2.1 mL/min. The autosampler injected 10 μL per 1.2 min, which was mixed with the F‐C reagent and heated to 65 °C while it passed through the column heater. The heated reactant was mixed with sodium carbonate and color intensity was measured by the detector at 600 nm. The data collection system recorded the color intensity, and peak area of each sample was calculated as the concentration of the total phenolic content, expressed in μg/mL as either chlorogenic acid or gallic acid. This new method had superb repeatability (0.7% CV) and a high correlation with both the manual method (r²= 0.93) and the HPLC method (r²= 0.78). Ascorbic acid and quercetin showed variable antioxidant activity, but sugars did not. This method can be efficiently applied to research that needs to test many numbers of antioxidant capacity samples with speed and accuracy.     

The relationship between the chemical structure and thermal conversion temperatures of thermally rearranged (TR) polymers

An attempt was made to elucidate the relationship between chemical structure, in terms of glass transition temperature (T_g), and conversion temperature (T_TR) of thermally rearranged polybenzoxazole membranes, by analyzing DSC and TGA data for a total of 15 sets of o-hydroxypolyimides and copolyimides, derived from two experimental and four commercial structurally different diamines, as well as four different dianhydride monomers. Our research revealed that T_TR was influenced by chain ridigity of o-hydroxypolyimides, and exhibited a linear relationship with T_g. Therefore, structure and thermal property of o-hydroxypolyimide should be considered when studying TR polymers to determine thermal conversion to polybenzoxazole.     

UV‐cured epoxy/graphene nanocomposite films: preparation,structure and electric heating performance

UV‐cured epoxy/graphene nanocomposite films with ca 100 µm thickness were manufactured by a facile cationic photopolymerization of 3,4‐epoxycyclohexylmethyl‐3′,4′‐epoxycyclohexane carboxylate mixtures including graphene sheets of 0.3 ? 10.0 wt%, which was initiated by triarylsulfonium hexafluoroantimonate salts. The microstructure and thermal and electrical properties of the UV‐cured epoxy/graphene nanocomposite films were investigated as a function of the graphene content. X‐ray diffraction patterns and TEM images confirm that graphene sheets are well dispersed in the UV‐cured epoxy resin matrix even with a high graphene content of 10.0 wt%. The electrical resistance of the nanocomposite films decreased dramatically from ca 10¹² Ω to ca 10² Ω with increasing graphene content, especially at a percolation threshold of 2.0 ? 3.0 wt%. Accordingly, the UV‐cured nanocomposite films including 5.0 ? 10.0 wt% graphene showed excellent electric heating performance in terms of temperature response as well as electric power efficiency at a given applied voltage. For a nanocomposite film with 10.0 wt% graphene, the maximum temperature of ca 138 °C was attained at an applied voltage of 15 V and a high electric power efficiency of ca 3.0 ± 0.3 mW °C^?1 was achieved. © 2014 Society of Chemical Industry     

Potential Chemical Markers for the Identification of Irradiated Sausages

Abstract: Hydrocarbons, gas compounds, and off‐odor volatiles were determined for irradiated (0 or 5 kGy) commercial sausages with different fat contents (16% and 29%) during a 60‐d storage period at 4 °C. Total of 4 hydrocarbons (C14:1, C15:0, C16:2, and C17:1) were detected only in irradiated sausages: the amount of C16:2 was the highest, followed by C17:1, C14:1, and C15:0. The concentrations of hydrocarbons decreased significantly (P < 0.05) with storage, but were still detectable at the end of 60‐d storage. Irradiated sausages produced significantly higher amounts of CO than the nonirradiated ones. CH₄ was detected only in irradiated sausages. Dimethyl disulfide was detected only in irradiated sausages and its concentration decreased significantly (P < 0.05) with storage. Fat content of sausages showed a significant effect on the production and retention of hydrocarbons, gas compounds, and sulfur volatiles in irradiated sausages during storage. Some hydrocarbons (C16:2, C17:1, C14:1, and C15:0), CH₄, and dimethyl disulfide were only found in irradiated sausages indicating that these compounds can be used as potential markers for irradiated sausages.