Hyporientalin A, an anti-Candida peptaibol from a marine Trichoderma orientale.

A Trichoderma orientale strain LSBA1 was isolated from the Mediterranean marine sponge Cymbaxinella damicornis. The crude extract of T. orientale mycelium showed inhibitory activity against growth of Gram-positive and Gram-negative bacteria as well as clinical isolates of Candida albicans. Purification of the anti-Candida component was performed using a combination of open silica gel-60 column and reverse phase high performance liquid chromatography. The active compound called hyporientalin A has been identified as a peptaibol analogue of longibrachin-A-II using mass spectrometry. It exhibited fungicidal activity against clinical isolates of C. albicans with minimal inhibitory concentrations (MICs) ranging from 2.49 to 19.66 µM, comparable to that of the antifungal agent amphotericin B. Our data support the use of hyporientalin A as a promising new and efficient antifungal drug in the treatment of candidiasis while controlling toxicity.

Production and identification of iturin A lipopeptide from Bacillus methyltrophicus TEB1 for control of Phoma tracheiphila.

A lipopeptide-producing endophytic Bacillus methyltrophicus TEB1 strain exhibited potent antifungal activity against Phoma tracheiphila. Lipopeptide production started at the early growth phase plateaued after 36 h of culture where it reduced the mycelium growth by 80%. The crude lipopeptide extract harvested at the stationary phase efficiently inhibited the growth of P. tracheiphila mycelium and MIC values displaying 50 and 90% inhibition of conidia germination were around 47.5 and 100 µg ml(-1) , respectively. Increasing lipopeptide extract till 3 mg ml(-1) induced 10% swelling and 3% crumbling of P. tracheiphila conidia whereas 5 mg ml(-1) induced 40% swelling and 20% crumbling. Mass spectrometry analysis of the lipopeptide extract indicated that surfactin production took place from 12 to 20 h, iturin A from 16 to 72 h, and fengycin from 12 to 72 h and that the main active compound against P. tracheiphila was identified as C15 iturin A lipopeptide. Iturin A appeared as a potential biological control agent able to substitute the currently used chemical pesticides in agriculture.