Rapid characterisation of deep-sea actinomycetes for biotechnology screening programmes

A continual need in natural product discovery is dereplication, that is the ability to exclude previously tested microorganisms from screening program mes. Whole-cell fingerprinting techniques offer an ideal solution to this p roblem because of their rapidity and reproducibility, dependence on small s amples, and automation. One such technique, Curie-point pyrolysis mass spec trometry (PyMS), has been deployed for the characterisation of a unique col lection of actinomycetes recovered from Pacific Ocean sediments approximate ly 2000 to 6500 m below sea level. This paper addresses the question: to wh at extent are pyrogroups, defined on the basis of PyMS fingerprinting, rela ted to classifications derived from more conventional microbial systematics ? A collection of 44 randomly chosen deep-sea rhodococci were coded and sub jected to a double-blind PyMS and numerical taxonomic (NT) analysis; the la tter sorted the strains into clusters (taxospecies) using large sets of equ ally weighted phenotypic data. At the end of the experiment the codes were disclosed and the NT classification shown to generate 6 homogeneous cluster s corresponding to different deep-sea sites. The matching of these clusters with the resulting pyrogroups was very high with an overall congruence of nearly 98%. Thus, PyMS characterisation is directly ascribable to the pheno typic variation being sought for biotechnology screens. Moreover, the exqui site discriminatory power of PyMS readily revealed infraspecific diversity in these industrially important bacteria.