Type Strains of Entomopathogenic Nematode-Symbiotic Bacterium Species, (EMC) and (EMA), Are Exceptional Sources of Non-Ribosomal Templated, Large-Target-Spectral, Thermotolerant-Antimicrobial Peptides (by Both), and Iodinin (by EMC).

Antimicrobial multidrug resistance (MDR) is a global challenge, not only for public health, but also for sustainable agriculture. Antibiotics used in humans should be ruled out for use in veterinary or agricultural settings. Applying antimicrobial peptide (AMP) molecules, produced by soil-born organisms for protecting (soil-born) plants, seems a preferable alternative.

Xenorhabdus antibiotics: a comparative analysis and potential utility for controlling mastitis caused by bacteria.

Aims: The role of antibiotics produced by bacterial symbionts of entomopathogenic nematodes is to suppress growth of microbes in the soil environment. These antibiotics are active against Gram-positive and Gram-negative bacteria, and were tested against mastitis isolates from dairy cows.

Methods And Results: Two bioassays were adapted for Xenorhabdus antibiotics; an overlay method on agar plates, and serially diluted, cell-free, Xenorhabdus cultures.

Xenofuranones A and B: phenylpyruvate dimers from Xenorhabdus szentirmaii.

Xenofuranones A (1) and B (2) have been isolated from cultures of the insect-pathogenic bacterium Xenorhabdus szentirmaii, and their structures were elucidated by NMR and mass spectroscopy. Both compounds show similarities to fungal furanones, and their biosynthesis was studied using a reversed approach by feeding putative 12C precursors to an overall 13C background in small-scale experiments followed by gas chromatographic analysis coupled to mass spectrometry.