Determining the Contribution of Epidermal Cell Shape to Petal Wettability Using Isogenic Antirrhinum Lines

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Twin cantilevers with a nanogap for single molecule experimentation

Single molecule experiments aimed both at fundamental investigation and applications, have been, recently, attracting a lot of attention. Most of the devices used for the detection and the manipulation of single molecules are based on very expensive lithographic tools, need a specific molecule labelling or functionalization and still show many limitations. We propose here an alternative approach based on the fabrication of pair of identical silicon cantilevers (the twin cantilevers), separated by a gap that is tuneable on the nanometric scale. The fabrication and operation of our twin cantilever device involves only the use of standard optical lithography and micrometric manipulation. We have investigated the frequency response of the twin cantilever device around its fundamental resonance, and, by modelling its behaviour, we show that a single molecule, spanning the cantilever gap, can, on paper, be detected

Diagram illustrating wettability behaviour of water on a rough surface.

<p><b>A</b>. Wenzel wetting, where the water is in close contact with the surface. <b>B.</b> Cassie-Baxter wetting where air is trapped between parts of the surface and the drop.</p

Designated wettability criteria and occurrence in Antirrhinum wild type (<i>Mx⁺</i>) and <i>mixta</i> (<i>mx⁻</i>) lines.

<p>Picture sequences refer to <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0017576#pone-0017576-g003" target="_blank">Figure 3</a>.</p

Nuclear export of the pre-60S ribosomal subunit through single nuclear pores observed in real time

Ribosomal biogenesis has been studied by biochemical, genetic and electron microscopic approaches, but live cell data on the in vivo kinetics are still missing. Here we analyse the export kinetics of the large ribosomal subunit (pre-60S particle) through single NPCs in human cells. We established a stable cell line co-expressing Halo-tagged eIF6 and GFP-fused NTF2 to simultaneously label pre-60S particles and NPCs, respectively. By combining single molecule tracking and super resolution confocal microscopy we visualize the dynamics of single pre-60S particles during export through single NPCs. For export events, maximum particle accumulation is found in the centre of the pore, while unsuccessful export terminates within the nuclear basket. The export has a single rate limiting step and a duration of ∼24 milliseconds. Only about 1/3 of attempted export events are successful. Our results show that the mass flux through a single NPC can reach up to ~125 MDa·s−1 in vivo.ISSN:2041-172