Botrytis polygoni, a new species of the genus Botrytis infecting Polygonaceae in Gansu, China.

A new species, Botrytis polygoni, was isolated from several species of Polygonaceae in 2011 and 2012 in Tongwei County, Gansu Province, China. The species infects Fagopyrum esculentum, F. tataricum, and Fallopia convolvulus, causing brown leaf spots and large blotches with concentric rings in the field. Botrytis polygoni is morphologically characterized by conidia spherical, unicellular, hyaline to pale brown or brown, (10.2-)14.3-21.4(-23.5) µm; and sclerotia black, spherical to subspherical, allantoid, or irregular-shaped, 0.2-4.1 × 0.1-3.0 mm. Comparison of the nuc rDNA internal transcribed spacer region (ITS1-5.8S-ITS2) sequences confirmed its placement in the genus Botrytis. Phylogenetic analysis based on the protein-coding genes glyceraldehyde 3-phosphate dehydrogenase (G3PDH), heat shock protein 60 (HSP60), and DNA-dependent RNA polymerase subunit II (RPB2) showed that the new species is clustered close but separate from Botrytis pyriformis, which was distant from 37 other Botrytis species and 17 undescribed species. Pathogenicity tests showed that the new species has aggressive pathogenicity to four species of Polygonaceae, specifically Fag. tataricum, Fal. convolvulus, Polygonum sibiricum, and Pol. aviculare, weak pathogenicity to Vicia faba in the Fabaceae, and no pathogenicity to eight other tested plants: Amaranthus retroflexus, Cirsium arvense, Convolvulus arvensis, Kalanchoe blossfeldiana, Lagopsis supine, Mentha canadensis, Plantago asiatica, and Raphanus sativus.

Quantitative video microscopy of patch clamped membranes stress, strain, capacitance, and stretch channel activation.

Membrane patches from chick skeletal muscle were stretched by applying controlled suction or pressure to the pipette. From images of the patch, the patch dimensions (area and radius of curvature) were computed by nonlinear regression of the images to a geometric model. With no applied pressure, patch membranes are nearly planar and normal to the wall of the pipette. With increasing pressure gradients, the patch bulges, the radius of curvature decreases, and the area increases. The patch capacitance changes in exact proportion to the change in area at a rate of 0.7 microF/cm2. The increase in area is due to a flow of lipid (with perhaps small amounts of diffusible protein) along the walls of the pipette into the patch. The flow is reversible with a relaxation of the pressure gradient. The area elastic constant of the membrane is approximately 50 dyn/cm, insensitive to cytochalasin B and probably represents the elasticity of the underlying spectrin/dystrophin network. Simultaneous measurements of stretch activated (SA) ion channel activity in the patch showed that the sensitivity of channels from different patches, although different when calculated as a function of applied pressure, was the same when calculated as a function of tension. Because patch lipid is free to flow, and hence stress-free in the steady state, SA channels must be activated by tension in the cytoskeleton.

Alignment of tomographic projections using an incomplete set of fiducial markers.

Reconstruction of three-dimensional images using tomography requires that the projections be aligned along a common rotational axis. We present here a solution to the problem of alignment for single-axis tomography using fiducial markers. The algorithm is based on iterative linearization of the projection equations and is least-squares-optimized by a linear least-squares solution instead of a gradient search. The algorithm does not require markers to be available in every projection, and initial estimates are unnecessary. Program execution is robust, fast, and can quickly align large data sets containing 256 or more projections.