Archive for the ‘Uncategorized’ Category

Teixobactin- A New Antibiotic kills pathogen without detectable resistance

Posted on: February 9th, 2015 by Ashok Bhonsle 2 Comments
As per the recent article published in Nature (January 2015), Ling L.L., et al., reported a new antibiotic – teixobactin, discovered in a screen of uncultured bacteria. Teixobactin inhibits cell wall synthesis by binding to a highly conserved motif of lipid II (precursor of peptidoglycan) and lipid III (precursor of cell wall teichoic acid). No any mutants of Staphylococcus aureus or Mycobacterium tuberculosis were found to be resistant to teixobactin. The properties of this compound suggested a path towards developing antibiotics that are likely to avoid development of resistance.Teixobactin- A New Antibiotic kills pathogen without detectable resistance.More reading:

Super-resolved Fluorescence Microscopy – Nobel Prize in Chemistry 2014

Posted on: February 9th, 2015 by Ashok Bhonsle 4 Comments

Eric Betzig, Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA, Stefan W. Hell, Max Planck Institute for Biophysical Chemistry, Göttingen, and German Cancer Research Center, Heidelberg, Germany   and William E. Moerner, Stanford University, Stanford, CA, USA shared the Noble Prize in chemistry  2014 for development of super resolved Fluorescence Microscopy.

Surpassing the limitations of the light microscope would never obtain the resolution half the wavelength of light. The Noble Laureates in Chemistry surpassed this limitation of 2000 X magnification with good resolution, to the level  of nanodimension.

Scientists visualize the pathways of individual molecules inside living cells. They can see how molecules create synapses between nerve cells in the brain; they can track proteins involved in Parkinson’s, Alzheimer’s and Huntington’s diseases as they aggregate; they follow individual proteins in fertilized eggs as these divide into embryos.

It was all but obvious that scientists should ever be able to study living cells in the tiniest molecular detail. In 1873, the microscopist Ernst Abbe stipulated a physical limit for the maximum resolution of traditional optical microscopy: it could never become better than 0.2 micrometres.  Eric Betzig, Stefan W. Hell and William E. Moerner are awarded the Nobel Prize in Chemistry 2014 for having bypassed this limit. Due to their achievements the optical microscope can now peer into the nanoworld.

Two separate principles are rewarded. One enables the method stimulated emission depletion (STED) microscopy, developed by Stefan Hell in 2000. Two laser beams are utilized; one stimulates fluorescent molecules to glow, another cancels out all fluorescence except for that in a nanometre-sized volume. Scanning over the sample, nanometre for nanometre, yields an image with a resolution better than Abbe’s stipulated limit.

Eric Betzig and William Moerner, working separately, laid the foundation for the second method, single-molecule microscopy. The method relies upon the possibility to turn the fluorescence of individual molecules on and off. Scientists image the same area multiple times, letting just a few interspersed molecules glow each time. Superimposing these images yields a dense super-image resolved at the nanolevel. In 2006 Eric Betzig utilized this method for the first time.

Today, nanoscopy is used world-wide and new knowledge of greatest benefit to mankind is produced on a daily basis.