Nematodes are one of the most abundant animals on earth, and bacteria comprise the most biologically and phylogenetically diverse domains of organisms. On at least two separate occasions a soil dwelling nematode and a bacterium have entered into a mutualistic, insecticidal association. From such origins arose two distinct lineages of nematode–bacterium entomopathogens, Steinernema–Xenorhabdus a...

The pyrrolobenzodiazepine tilivalline (1) was originally identified in the human gut pathobiont Klebsiella oxytoca, the causative agent of antibiotic-associated hemorrhagic colitis. Here we show the identification of tilivalline and analogs thereof in the entomopathogenic bacterium Xenorhabdus eapokensis as well as the identification of its biosynthesis gene cluster encoding a bimodular non-rib...

Xenorhabdus luminescens Hm cultured in gelatin broth produced a single extracellular protease. The protease was purified by a factor of 500 and characterized as a monomeric protein with an approximate molecular weight of 61,000. On the basis of inhibitor studies and its pH optimum, the protease was classified as an alkaline metalloprotease with a pH optimum near 8; the isoelectric point of the ...

Abstract The soil-dwelling nematode Steinernema feltiae is found across a wide range of environmental conditions. We asked if its only bacterial symbiont, Xenorhabdus bovienii , shows intraspecific variability in thermal range, which may affect effectiveness S. against host insects. isolated X. from six different natural locations with mean annual temperatures and two laboratory cultures. estim...

Competition among different parasite genotypes within a host is predicted to affect virulence. The direction of this effect, however, depends critically on the mechanisms that parasites use to compete or to cooperate with each other. One mechanism that bacteria use to compete with each other is via the production of bacteria-killing toxins, called bacteriocins. This warfare among parasites with...

The bacterium Xenorhabdus nematophila is an insect pathogen that produces several proteins that enable it to kill insects. Screening of a cosmid library constructed from X. nematophila strain A24 identified a gene that encoded a novel protein that was toxic to insects. The 42-kDa protein encoded by the toxin gene was expressed and purified from a recombinant system, and was shown to kill the la...