Improving your image

Image: Lothar Schermelleh, Wikimedia Commons (adapted from Schermelleh et al., Science 320: 1332–1336).

Gene sequences are all very well. But even the most committed of gene-genies/gel-jockies will usually admit that the hard work is not the sequencing but working out what all those genes do in the intact organism. An equally important aspect of that puzzle is to relate function to structure, which in turn relies upon improved techniques to provide the necessary structural resolution. To help with the latter aspect we offer news of several developments in biological imaging. Jessica Fitzgibbon and colleagues used three-dimensional structured illumination microscopy (3D-SIM) to obtain subdiffraction images of plasmodesmata (Plant Physiology 153:1453–1463, 2010). This breakthrough technique effectively gives ‘super-resolution’, which helps to bridge the information gap between confocal and electron microscopy (EM). On the subject of increasing resolution, Ann McEvoy et al. extol the virtues of SMLM (single-molecule light microscopy), which permits 25-nm resolution viewing with a light microscope (http://www.biomedcentral.com/1741-7007/8/106), which is about a 10-fold increase over what you could normally attain with that sort of microscope. SMLM neatly combines the specificity of labelled probes with the resolution of the EM, but with the advantage that SMLM can be used on living cells. Ante-pre-penultimately, and slightly to one side of the headlong rush to achieve EM resolution at the light-microscope level, Romain Fernandez et al. (Nature Methods, doi:10.1038/nmeth.1472) present a technique for imaging plant growth in four dimensions – i.e. in 3D but with a temporal component, too. Demonstrating its potential they analysed quantitatively Arabidopsis thaliana flower development at cell-level resolution, and revealed differential growth patterns of key regions during early stages of floral morphogenesis. Linking the visualisation techniques with various reporters of gene function helps to provide that vital link between genotype and phenotype. Pre-penultimately, adding an important temporal dimension to EM imaging (notorious for its static views of fixed material, frustrating attempts to understand dynamic processes in hydrated tissues at EM resolution), Juliette McGregor and Athene Donald show that some extremely sensitive plant processes can be viewed at the EM level (Journal of Microscopy 239: 135–141, 2010). Demonstrating the potential of the ESEM (environmental scanning electron microscope), which permits imaging of hydrated tissues in an electron beam, the duo successfully showed that closure of Tradescantia stomata can be followed using that methodology. Penultimately – and for those who just love what can be achieved when the power of the SEM (scanning electron microscope) is coupled to image manipulation software – the stunning images of pollen captured and ‘enhanced’ by Martin Oeggerli are always worth a look (even if you suffer from hay fever!) (http://www.telegraph.co.uk/science/picture-galleries/7606811/Hayfever-sufferers-know-your-enemy-Scanning-Electron-Microscope-pictures-of-grains-of-pollen.html). Ultimately, if you’ve ever wondered what the inside of vegetable foodstuffs look like using MRI (magnetic resonance imaging), then visit http://insideinsides.blogspot.com/.