Ampullosporin, a New Peptaibol-type Antibiotic from Sepedonium ampullosporum HKI-0053 with Neuroleptic Activity in Mice.

Abstract

Ampullosporin (I; Ac-Trp-Ala-Aib-Aib-Leu-Aib-Gln-Aib-Aib-Aib-Gln-Leu-Aib-Gln-Leuol) was isolated from the mycelium of Sepedonium ampullosporum as a new 15-membered peptaibol-type antibiotic. The structure was determined by mass spectrometric and two-dimensional NMR experiments. Ampullosporin displays narrow-spectrum antibacterial and antifungal activity, induces pigment formation by Phomadestructive causes hypothermia and decreased spontaneous locomotor activity in mice in dosages > 1 mg/kg.Microbial metabolites inducing the morphogenesis and cytodifferentiation of other microbes have been shown to display interesting pharmacological activities1}. Recently we described a fungal strain, Phomadestructive which responded during surface cultivation to small amounts of cyclosporin A by the formation of a blackish pigment2). In a screening for similar inducers of pigment formation we discovered the chrysospermins2'3) as new peptaibol-type antibiotics4) from Apiocrea chrysosperma which showed the same effect as this immunomodulatory compound. But several other peptaibols such as alamethicin4) and bergofungin5) failed to afford this phenomenon.In order to obtain moreinformation about structureactivity relationships of the peptaibol antibiotics as inducers of pigment formation, we searched for other peptides from fungal cultures that could affect Phoma destructiva. Here, we report on a newpeptaibol-type antibiotic, ampullosporin (I) from Sepedonium ampullosporum HKI-0053, which is active in the same manner as described for cyclosporin A and chrysospermins2). Moreover, ampullosporin was found to induce hypothermia in mice suggesting a neuroleptic activity. Materials and MethodsMicroorganism and Cultivation Sepedonium ampullosporutn HKI-0053 was obtained from the culture collection of the Hans-Knoll-Institute of Natural Product Research Jena (Germany). The strain SEPT. 1997 was deposited in the DSMZculture collection (Braunschweig, Germany) under the registry number DSM 10602. Fifteen days agar-plate cultures (25°C) were prepared as seed mediumcomposed of malt extract 4%, yeast extract 0.4%, agar 1.5% and deionized water, pH 6.0. Four to five cm2 areas of the agar-plate cultures were used to inoculate a liquid mediumcomposed of glycerol 3%, glucose 1%, peptone 0.5%, NaCl 0.2%, molecular sieve (0.5nm, Merck) 0.1% and agar 0.1%, pH 7.0. The surface cultivation was carried out at 25°C in 1 liter Erlenmeyer flasks containing 100ml of the above medium for two weeks. Subsequently, the whole culture broth was extracted twice with two volumes of ethyl acetate.Instruments and Analytical Methods HPLCwas carried out using a Gilson binary gradient HPLCsystem equipped with a UV detector (210nm). Positive ion FABmass spectra were recorded on an AMD402 double-focussing mass-spectrometer with BE geometry (AMD, Intectra, Harpstedt, Germany). Ions were produced by Cs+ ion bombardment generated by a Cs+ gun (liquid SIMSsystem, AMDIntectra). Peptide solutions were mixed with 3-nitrobenzyl alcohol as matrix on the FABprobe tip. High-resolution...

The occurrence of peptaibols and structurally related peptaibiotics in fungi and their mass spectrometric identification via diagnostic fragment ions

“…Inhibition of mitochondrial ATPase, uncoupling of oxidative phosphorylation, immunosuppression [3][4][5][6][7], inhibition of platelet aggregation [8], induction of fungal morphogenesis and neuroleptic effects [9][10][11][12] have been reported.…”

Channel-Forming Peptaibols Are Potent Elicitors of Plant Secondary Metabolism and Tendril Coiling

“…Ac-Aib-Pro-Aib-Ala-Aib-Ala-Gln-Aib-Val-Aib-Gly-Leu-Aib-Pro-Val-Aib-Aib-Gln-Gln-Pheol ampullosporin A [8] Ac-Trp-Ala-Aib-Aib-Leu-Aib-Gln-Aib-Aib-Aib-Gln-Leu-Aib-Gln-Leuol bergofungins [25] A: Ac-Val-Aib-Aib-Aib-Val-Gly-Leu-Aib-Aib-Hyp-Gln-iVal-Hyp-Aib-Pheol B: Ac-Val-Aib-Aib-Aib-Val-Gly-Leu-Val-Aib-Hyp-Gln-iVal-Hyp-Aib-Pheol C: Ac-Val-Aib-Aib-Aib-Val-Gly-Leu-Aib-Aib-Hyp-Gln-Aib-Hyp-Aib-Pheol chrysospermin A [9] [b]…”

“…[7] Characteristic features of their chemical structures are the acylated N terminus, and the presence of a-aminoisobutyric acid (Aib) and C terminal a-amino alcohols (peptaibols). They occur mainly as large 18-to 20-membered peptaibols, such as alamethicin, [7] ampullosporin [8] and chrysospermin, [9] and as smaller 15-to 16-membered species, such as antiamoebin. [10] Their antimicrobial activity is largely due to the formation of a-helical structures which produce voltage-dependent or voltage-independent ion channels within biological membranes.…”

Peptaibiomics: Towards a Myriad of Bioactive Peptides Containing Cα‐Dialkylamino Acids?

“…Apiocrea chrysosperma), biosynthesizing four 19-residue chrysospermins A -D [133]; Sepedonium ampullosporum DSM 10602, source of the neuroleptic 15-residue ampullosporin A [134], and further seven minor components, ampullosporins B -E 4 [135]. This strain also produced the five-residue peptaibolin, the shortest peptaibol reported in literature to date [136].…”

“…The producer has been isolated from a decaying fruiting body found in the Kamai Ranges near Kaitaki, Bay of Plenty, New Zealand, and reported as Sepedonium chrysospermum [226]. Chrysaibol exhibits structural homology with ampullosporin A [134], both displaying the common motif Gln-Aib-Aib-Aib-Gln-Leu-Aib and the N-terminal AcTrp residue. Because of the latter, we predict a neuroleptic activity for chrysaibol, in addition to the cytotoxic (P388 murine leukemia cells) and antimicrobial effects (Bacillus subtilis) reported.…”