Simple, but Not Branched, Plasmodesmata Allow the Nonspecific Trafficking of Proteins in Developing Tobacco Leaves

AbstractLeaves undergo a sink–source transition during which a physiological change occurs from carbon import to export. In sink leaves, biolistic bombardment of plasmids encoding GFP-fusion proteins demonstrated that proteins with an Mr up to 50 kDa could move freely through plasmodesmata. During the sink–source transition, the capacity to traffic proteins decreased substantially and was accompanied by a developmental switch from simple to branched forms of plasmodesmata. Inoculation of sink leaves with a movement protein-defective virus showed that virally expressed GFP, but not viral RNA, was capable of trafficking between sink cells during infection. Contrary to dogma that plasmodesmata have a size exclusion limit below 1 kDa, the data demonstrate that nonspecific “macromolecular trafficking” is a general feature of simple plasmodesmata in sink leaves

On a practical distributed source coding scheme for wireless sensor networks

The new European X-ray Free-Electron Laser is the first X-ray free-electron laser capable of delivering X-ray pulses with a megahertz inter-pulse spacing, more than four orders of magnitude higher than previously possible. However, to date, it has been unclear whether it would indeed be possible to measure high-quality diffraction data at megahertz pulse repetition rates. Here, we show that high-quality structures can indeed be obtained using currently available operating conditions at the European XFEL. We present two complete data sets, one from the well-known model system lysozyme and the other from a so far unknown complex of a β-lactamase from K. pneumoniae involved in antibiotic resistance. This result opens up megahertz serial femtosecond crystallography (SFX) as a tool for reliable structure determination, substrate screening and the efficient measurement of the evolution and dynamics of molecular structures using megahertz repetition rate pulses available at this new class of X-ray laser source