Differentiation of citrus bacterial canker strains in Korea by host range,rep-PCR fingerprinting and 16S rDNA analysis

Soil-borne cereal mosaic virus (SBCMV) causes a severe disease in susceptible cultivars of winter wheat. The virus is vectored by the soil-borne protist Polymyxa graminis. Experiments were conducted to investigate whether SBCMV RNA2 could persist in seed from SBCMV-infected susceptible cultivars of winter wheat. Over 7,000 seedlings were generated from seed collected from two cultivars of SBCMV-infected winter wheat. Seedlings were grown in a glasshouse compartment and batch tested for the presence of SBCMV using real-time RT-PCR. The majority of batches tested positive for SBCMV, indicating an RNA2 transmission rate of 1.8–9.4% in wheat. The presence of the virus was confirmed by amplifying and sequencing a larger (400 bp) fragment of viral RNA2 in a sub-set of the seedlings testing positive by real-time RT-PCR. Root extracts from this sub-set tested negative for P. graminis using real-time PCR. The implications for disease epidemiology of this virus are discussed. The authors are British Civil Servants and as such their work is subject to British Crown Copyright. This means the exclusive copyright for the article cannot be transferred.     

Kinetics of Hg adsorption onto noncrystalline Al hydroxide as influenced by low-molecular-weight organic ligands

This study was conducted to investigate the kinetics of Hg adsorption by noncrystalline Al hydroxide as influenced by various pH conditions and cysteine (cys), glycine (gly), and citric acid (cit), which have different structures and functionalities, as low-molecular-weight organic ligands using the GEOCHEM-PC software. The influence of these organic ligands on the kinetics of Hg adsorption varied according to their concentration, structure, and functionality and pH. The adsorption of Hg followed multiple first order kinetics with initial rapid adsorption, followed by slow adsorption. Cysteine suppressed or enhanced Hg adsorption, depending on pH and its concentration. Glycine and citric acid exerted suppressing and enhancing effects, respectively, with the exception of at pH 4.5 and at lower concentrations, at which no influence was observed as compared to the control. Two mechanisms were thought to mediate the adsorption of Hg(II); specific surface complexation in the control, cysteine and glycine systems, and ligand exchange in the citric acid system. The Hg adsorption at all levels of organic ligands decreased with increasing pH, with the exception of at the higher concentration of cysteine, at which the reverse trend was observed. The influence of organic ligands on the dynamics of Hg in the freshwater environment merits further study.     

Miscibility, structural characteristics, and thermal behavior of wet spun regenerated silk fibroin/nylon 6 blend filaments

In this study, the regenerated silk fibroin (SF)/nylon 6 blend filaments were fabricated by the wet spinning and miscibility, structural characteristics, and thermal behavior of blend filaments were elucidated. The XRD results implied that the amount of crystalline region of each polymer did not change linearly with the blend ratio suggesting that there are some changes in the miscibility depending on the mixing ratio. The SEM observation revealed that the miscibility of blend decreased with an increase of nylon 6 resulting in a severe phase separation in 50/50 SF/nylon 6 filament. The miscibility governed the thermal behavior of blend filaments. The melting point of nylon 6 remained constant until 50 % nylon 6 content, whereas the melting point depression appeared in 30 % nylon 6 implying miscibility. Interestingly, the thermal decomposition of the nylon 6 component was accelerated by the presence of SF and the acceleration action of SF became stronger as the miscibility increased.     

Three AFLP markers tightly linked to the genic male sterility <Emphasis Type="Italic">ms</Emphasis><Subscript><Emphasis Type="Italic">3</Emphasis></Subscript> gene in chili pepper (<Emphasis Type="Italic">Capsicum annuum</Emphasis> L.) and conversion to a CAPS marker

Genic male sterility (GMS) has long been used as a tool for hybrid seed production in chili pepper (Capsicum annuum L.). We developed DNA markers linked to the GMS ms ₃ gene in a segregating population using bulked segregant analysis (BSA) and amplified fragment length polymorphism (AFLP) techniques. The segregating population was subjected to BSA-AFLP with 512 primer combinations. Three AFLP markers (Eagg/Mccc₂₇₆, Eagc/Mctt₁₇₈, and Ecag/Mtgc₂₀₄) were identified as tightly linked to the ms ₃ locus. Among them, we converted the AFLP marker Ecag/Mtgc₂₀₄ to the cleavage amplified polymorphic sequence (CAPS) marker, named GMS3-CAPS, based on sequencing analysis of internal and flanking regions for the markers between male-fertile and sterile plants. This marker will be useful for pepper breeding using the GMS system.     

Allosteric supramolecular triple-layer catalysts

Allosteric regulation of organometallic catalysts could allow for greater control over reactions. We report an allosteric supramolecular structure in which a monometallic catalytic site has been buried in the middle layer of a triple-layer complex. Small molecules and elemental anions can open and close this complex and reversibly expose and conceal the catalytic center. The ring-opening polymerization of ε-caprolactone can be turned on by the in situ opening of the triple-layer complex and then completely turned off by reforming it through the abstraction of Cl(-), the allosteric effector agent, without appreciable loss of catalytic activity. This process can regulate the molecular weights of the resulting polymers.     

64-Channel multi-detector row CT angiographic evaluation of the micropigs for potential living donor lung transplantation

Micropigs are the most likely source animals for xenotransplantation. However, an appropriate method for evaluating the lung of micropigs had not been established. Therefore, this study was performed to evaluate the feasibility of 64-channel multi-detector row computed tomography (MDCT) to measure the diameter of the pulmonary arteries and the lung volume in micropigs. The mean diameters of the trachea, and left and right bronchi were 1.6 ± 0.17, 1.18 ± 0.14, and 1.1 ± 0.11 cm, respectively. The mean diameters of the main, right, and left pulmonary arteries were 1.38 ± 0.09, 1.07 ± 0.26, and 0.98 ± 0.13 cm and the diameters of right, left, and common inferior pulmonary veins were 0.97 ± 0.20, 0.76 ± 0.20, and 1.99 ± 0.26 cm, respectively. The mean lung volume was 820.3 ± 77.11 mL. The data presented in this study suggest that the MDCT may be a noninvasive, rapid, and accurate investigational method for pulmonary anatomy in living lung donors.     

Adsorption of metal and uranyl ions onto amidoximated Pinus densiflora bark

Pine (Pinus densiflora) bark was chemically modified by grafting with acrylonitrile (AN) through Fenton reaction and conversion of the cyano group to an amidoxime group by reaction with hydroxylamine. Treatments of pine bark with 160 mM H₂O₂ at 40°C yielded ~70% grafting in 6-h reaction. After alkali hydrolysis of amidoximated pine bark (AOPB), its adsorption capacity (q _e) for copper ions was largely increased from 0.5 to 1.8 mmol/g. Adsorption of the hydrolyzed AOPB (HAOPB) followed the pseudo-second-order kinetic model. Among the metal ions tested, the order of adsorption capacity (q _e) predicted by the kinetic model at equilibrium time was Hg²⁺ > UO₂ ²⁺ > Cd²⁺ > Cu²⁺ > Zn²⁺ > Ni²⁺. The adsorption process was pH-dependent, and the adsorption equilibrium was observed in the pH range of 6–7 for all the metal ions. Even though pine bark is a good adsorbent for Hg²⁺ and UO₂ ²⁺ ions, it had a poor affinity for the other ions tested. It was obviously found that HAOPB had very high adsorption abilities for heavy metal and uranyl ions.     

Development of a co-dominant SCAR marker linked to the Ph-3 gene for Phytophthora infestans resistance in tomato (Solanum lycopersicum)

Random amplified polymorphism DNA (RAPD) and bulk segregant analysis (BSA) approaches were used to characterize the molecular marker linked to the Phytophthora infestans resistance gene Ph-3 in tomato. A total of 800 RAPD primers were screened. One RAPD marker UBC#602 was identified to be tightly linked to the Ph-3 gene. The marker was successfully converted into a co-dominant sequence characterized amplified region (SCAR) marker. The SCAR marker SCU602 was used to analyze 96 F₂ progenies and fitted the expected 1:2:1 Mendelian segregation ratio. Forty one tomato inbred lines were screened using the SCAR marker in comparison with a reference marker linked to the Ph-3 gene and both markers gave the same results. SCU602 was further validated for association to resistance and its potential in MAS in 72 tomato lines and cultivars. The marker identified three genotypes harbouring the resistance allele. This SCAR marker can be used in breeding programs for the selection of the Ph-3 gene for Phytophthora infestans resistance.     

An antibiotic fusaricidin: a cyclic depsipeptide from Paenibacillus polymyxa E681 induces systemic resistance against Phytophthora blight of red-pepper

In this study fusaricidin, a cyclic depsipeptide isolated from Paenibacillus polymyxa E681 (E681), was demonstrated to control Phytophthora blight infection caused by Phytophthora capsici in red-pepper. The minimal inhibitory concentration (MIC) of fusaricidin was found to be 16 ppm against P. capsici. The disease severity of P. capsici was 40% at 0.1 ppm of fusaricidin when compared with water-treated control (81.7%) on post-treatment, whereas the disease severities on pre-treatment were 45% and 83.3% in fusaricidin (0.1 ppm) and water-treated control, respectively, in red-pepper plants. Significant (P?<?0.05) disease suppression was observed on treatment with fusaricidin (0.1 ppm) by foliar spray and soil drench. The disease severity was drastically reduced to 3.3% by soil drench of fusaricidin (1.0 ppm), whereas in water-treated control, the disease severity was 83.3% in the first experiment. Fusaricidin at 0.1 ppm reduced disease severity of P. capsici to 27.5% when compared with positive control (43.1%) and water-treated control (66.2%) in the second experiment. Soft rot disease in tobacco was suppressed upon treatment with fusaricidin at 1.0 ppm by leaf infiltration. RT-PCR analyses of Arabidopsis thaliana revealed that there was an up-regulation of pathogenesis-related (PR) gene expression in wild type A. thaliana (Col-0), while there was no accumulation of PR genes, which implies that the mechanism of protection might be based on a salicylic acid-dependent pathway. This is the first report that fusaricidin exhibits protection against plant pathogens in addition to activity as an antibiotic agent. Hence, E681 can play a role in plant protection by secretion of ISR elicitors including fusaricidin.     

Mass production of rubusoside using a novel stevioside-specific β-glucosidase from Aspergillus aculeatus

Rubusoside (R) is a natural sweetener and a solubilizing agent with antiangiogenic and antiallergic properties. However, currently, its production is quite expensive, and therefore, we have investigated nine commercially available glycosidases to optimize an economically viable R-production method. A stevioside (ST)-specific β-glucosidase (SSGase) was selected and purified 7-fold from Aspergillus aculeatus Viscozyme L by a two-step column chromatography procedure. The 79 kDa protein was stable from pH 3.0 to pH 7.0 at 50-60 °C. Hydrolysis of ST by SSGase produced R and steviol monoglucosyl ester as determined by (1)H and (13)C nuclear magnetic resonance (NMR). Importantly, SSGase showed higher activity toward ST than other β-linked glucobioses. The optimal conditions for R production were 280 mM ST and 16.6 μL of SSGase at pH 5.1 and 63 °C. This is the first discussion detailing the production of R by enzymatic hydrolysis of ST and is useful for the food additive and pharmaceutical industries.