ABSTRACT
Macrocyclic PKS-NRPS hybrid metabolites represent a unique family of natural products mainly from bacteria with broad and outstanding biological activities. However, their distribution in fungi has rarely been reported, and little has been reported regarding their nematocidal activity. Here we describe an unprecedented class of PKS-NRPS hybrid metabolites possessing a 13-membered lactam-bearing macrolactone, thermolides A-F (1-6) from a thermophilic fungus Talaromyces thermophilus. We showed that 1 and 2 displayed potent inhibitory activity against three notorious nematodes with LC(50) values of 0.5-1 µg/mL, as active as commercial avermectins. This work provided a new class of promising lead compounds for nematocide discovery.
Subject(s)
Antinematodal Agents/isolation & purification , Polyketide Synthases/metabolism , Talaromyces/metabolism , Antinematodal Agents/pharmacology , Magnetic Resonance SpectroscopyABSTRACT
Arthrobotrys oligospora is a carnivorous fungus that can use mycelia trapping devices to capture their prey. Three novel oligosporons, named arthrobotrisins A-C (1-3), were isolated from A. oligospora and identified by spectroscopic analysis in combination with X-ray diffraction. This is the first time that the relative configuration of naturally occurring oligosporon metabolites has been fully determined. Compound 3 exhibited specific antibacterial activities.
Subject(s)
Anti-Bacterial Agents/isolation & purification , Antinematodal Agents/isolation & purification , Epoxy Compounds/isolation & purification , Mitosporic Fungi/chemistry , Nematoda/drug effects , Animals , Anti-Bacterial Agents/chemistry , Anti-Bacterial Agents/pharmacology , Antinematodal Agents/chemistry , Antinematodal Agents/pharmacology , Crystallography, X-Ray , Epoxy Compounds/chemistry , Epoxy Compounds/pharmacology , Molecular Conformation , Molecular StructureABSTRACT
The putative key biosynthetic intermediates of prenylated indole alkaloids have long been proposed but never isolated. Two such alkaloids, named talathermophilins A and B (1 and 2), were isolated from a thermophilic fungus Talaromyces thermophilus strain YM1-3 and were identified by NMR and MS spectroscopic analyses. The ratio of 1 and 2 in the culture broths was unexpectedly rather constant (about 2:3), which even remained unchanged despite the addition of exogenous 1 or 2, suggesting that talathermophilins might be of special function for the extremophilic fungus.
Subject(s)
Indole Alkaloids/chemistry , Talaromyces/chemistry , Indole Alkaloids/isolation & purification , Indole Alkaloids/metabolism , Molecular Structure , Prenylation , Talaromyces/metabolismABSTRACT
Chemical investigation of one fungal strain P. chlamydosporia YMF 1.00613 isolated from root knots of tobacco infected by Meloidogyne incognita led to the isolation and identification of four aurovertin-type metabolites, which include a new compound, aurovertin I (A1), and three known metabolites, aurovertins E, F and D (A2-A4). Their structures were established by spectroscopic studies such as 1D- and 2D-NMR and MS analysis. Aurovertin I (A1) is the first natural product with an aurovertin skeleton with one less carbon. Compounds A3 and A4 showed the toxicity to the worms of the free-living nematode Panagrellus redivevus with the LC(50) values 88.6 and 41.7 microg/mL at 48 h, respectively. All four aurovertins did not show obvious inhibitory effects on egg hatch of root knot nematode Meloidogyne incognita. The results suggested that the aurovertin-type metabolites produced by P. chlamydosporia might be one of the pathogenic factors involved in the suppression of nematodes.
