Search

Phytophthora capsici is an oomycete plant pathogen that infects peppers, tomatoes, and other agronomic and ornamental crops of the Solanaceae and Cucurbitaceae families worldwide. Early and accurate detection of P. capsici is essential for controlling this disease in the field. The internal transcribed spacer (ITS) regions of nuclear-encoded ribosomal DNA genes are widely used to detect Phytophthora nicotianae, Pythium helicoides and Peronospora variabilis. In this study, a novel and highly sensitive loop-mediated isothermal amplification (LAMP) assay was developed for the specific detection of P. capsici using calcein as a fluorescent indicator. Four LAMP primers were designed based on the ITS sequence of P. capsici. A total of 23 isolates of P. capsici from geographically distinct counties in China yielded positive results in the LAMP assay. No cross-reaction was observed with other oomycetes or fungal pathogens. The detection limit of P. capsici by LAMP was 100 fg genomic DNA per 25 μL reaction. The LAMP assay developed in this study is simple, fast, sensitive and specific, and can be used in the field to detect P. capsici in infected plant tissue. [ABSTRACT FROM AUTHOR]

Abstract: Multi-channel TiO2 membranes with an average pore size of 3.3nm for ultrafiltration were fabricated via a template assisted sol–gel process, during which the triblock polymer L64 was used as a template to modify the properties of the sols and finally improved the separation performance of the membranes. To optimize the coating and sintering temperature, the relationships of viscosity–temperature curves of the sols and the thermal properties of the gels were investigated. The viscosity–temperature curves were all linear curves with two intersectional points. The viscosity of the sol with 11.8wt% of L64 is 8.6mPas at the first intersectional point of 25°C, which was suitable for coating membrane. The TG–DSC curves proved that the L64 was removed from the as-synthesized TiO2 upon calcination at 400°C, which was chosen as the calcination temperature and the membrane could be obtained by dip-coating on a 19-channel ZrO2 support after five cycles of aging and calcining. The resulted multi-channel TiO2 membrane owing to a large specific surface area of 94.3m2/g and a small anatase crystallite size of 9.0nm, presented good ultrafiltration property. In dextran filtration experiments, its molecular weight cut-off was 5000Da, which meant a crack-free multichannel TiO2 ultrafiltration membrane was successfully fabricated using this method. [Copyright &y& Elsevier]