as providing enough amounts of bromide and iron,
elements frequently observed in halogenated marine-derived compounds or of limited access in marine
environments [39,44]. As previously observed with other examples of the family Microccocaceae, the
compound was only produced in this medium in the absence of marine salts, conditions that were used to
scale up the production for the isolation of the molecule. In fact, our group had already described two
related strains of Microccocaceae corresponding to the species Arthrobacter, R-7513 and R-7914
(Figure 1), which were isolated in a previous study from Antarctic microbial mats. Both strains produced
Mar. Drugs 2013, 11 1078
a potent anti-MRSA compound characterized by a major LCMS peak of 1514 Da proposed at that time as a new thiazolyl peptide [21] that we confirmed to correspond to kocurin (data not shown). In contrast to the Kocuria and Micrococcus strains, both strains of Arthrobacter produce kocurin in the medium CGY [21], a medium also used in our study without success.