. Author manuscript; available in PMC: 2015 Feb 1.
Published in final edited form as: J Antibiot (Tokyo). 2014 Apr 9;67(8):571–575. doi: 10.1038/ja.2014.37
Users may view, print, copy, and download text and data-mine the content in such documents, for the purposes of academic research, subject always to the full Conditions of use:http://www.nature.com/authors/editorial_policies/license.html#terms