Rhodococcus erythropolis MTHt3 biotransforms ergopeptines to lysergic acid.

Michaela Thamhesl,Elisavet Kunz-Vekiru,Wolfgang Kneifel,Rudolf Krska,Wulf-Dieter Moll,Gerd Schatzmayr,Heidi Elisabeth Schwartz-Zimmermann,Elisabeth Apfelthaler

doi:10.1186/s12866-015-0407-7

Michaela Thamhesl, Elisavet Kunz-Vekiru + Show 6 more

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https://doi.org/10.1186/s12866-015-0407-7

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Abstract

BackgroundErgopeptines are a predominant class of ergot alkaloids produced by tall fescue grass endophyte Neotyphodium coenophialum or cereal pathogen Claviceps purpurea. The vasoconstrictive activity of ergopeptines makes them toxic for mammals, and they can be a problem in animal husbandry.ResultsWe isolated an ergopeptine degrading bacterial strain, MTHt3, and classified it, based on its 16S rDNA sequence, as a strain of Rhodococcus erythropolis (Nocardiaceae, Actinobacteria). For strain isolation, mixed microbial cultures were obtained from artificially ergot alkaloid-enriched soil, and provided with the ergopeptine ergotamine in mineral medium for enrichment. Individual colonies derived from such mixed cultures were screened for ergotamine degradation by high performance liquid chromatography and fluorescence detection. R. erythropolis MTHt3 converted ergotamine to ergine (lysergic acid amide) and further to lysergic acid, which accumulated as an end product. No other tested R. erythropolis strain degraded ergotamine. R. erythropolis MTHt3 degraded all ergopeptines found in an ergot extract, namely ergotamine, ergovaline, ergocristine, ergocryptine, ergocornine, and ergosine, but the simpler lysergic acid derivatives agroclavine, chanoclavine, and ergometrine were not degraded. Temperature and pH dependence of ergotamine and ergine bioconversion activity was different for the two reactions.ConclusionsDegradation of ergopeptines to ergine is a previously unknown microbial reaction. The reaction end product, lysergic acid, has no or much lower vasoconstrictive activity than ergopeptines. If the genes encoding enzymes for ergopeptine catabolism can be cloned and expressed in recombinant hosts, application of ergopeptine and ergine degrading enzymes for reduction of toxicity of ergot alkaloid-contaminated animal feed may be feasible.

Highlights

Ergopeptines are a predominant class of ergot alkaloids produced by tall fescue grass endophyte Neotyphodium coenophialum or cereal pathogen Claviceps purpurea
Degradation of the ergot alkaloids used as screening substrate, ergotamine and ergine, was repeatedly observed when sample resuspensions in various growth media or buffers were incubated with substrate under aerobic or anaerobic conditions
Five bacterial and five yeast strains with ergine bioconversion activity, but no strains with ergotamine bioconversion activity, were found

Summary

Introduction

Ergopeptines are a predominant class of ergot alkaloids produced by tall fescue grass endophyte Neotyphodium coenophialum or cereal pathogen Claviceps purpurea. Ergot alkaloids occur widely in nature because some ergot alkaloid-producing fungi form intricate associations with plants. Such associations range from mutualistic endosymbiotic life of Neotyphodium or Epichloë species as endophytes in certain grasses [1], and Periglandula species in morning glory [2], to parasitic association of Claviceps species with rye, sorghum and other cereal plants [3]. Ergopeptines typically represent a major proportion of total ergot alkaloids both in sclerotia, which are hard, pigmented mycelium structures formed by Claviceps purpurea as wintering bodies on cereal ears, and in endophyte infected grass. The lefthand rotation isomers (C-8(R) configuration) are pharmacologically active, and are named with the suffix –ine (e.g., Thamhesl et al BMC Microbiology (2015) 15:73

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