title: Identification of compounds with bioactivity against the nematode Caenorhabditis elegans by a screen based on the functional genomics of the marine bacterium Pseudoalteromonas tunicata D2.
abstract: Marine bacteria are a rich, yet underexplored, resource of compounds with inhibitory bioactivity against a range of eukaryotic target organisms. Identification of those inhibitors, however, requires a culturable or genetically tractable producer strain, a prerequisite that is not often fulfilled. This study describes a novel functional genomic screen that is based on expression of inhibitors in a heterogeneous recombinant host (i.e., Escherichia coli). Functional libraries were screened by selective grazing by the nematode Caenorhabditis elegans, in a simple, rapid, high-throughput manner. We applied our approach to discover inhibitors of C. elegans produced by the marine bacterium Pseudoalteromonas tunicata D2, a model organism for exploring a range of antagonistic activities between bacteria and eukaryotes and a known producer of several toxic compounds. Expression of P. tunicata DNA in E. coli and grazing selection by the nematode Caenorhabditis elegans identified two clones, with slow- and fast-killing modes of action. Genomic analysis of the slow-killing clone revealed that the activity was due to a small molecule, tambjamine, while the fast-killing activity involved a gene encoding for a novel protein. Microscopic analysis showed substantial colonization of the intestinal lumen, or rapid death of the nematode without colonization, for the two activities, respectively. The novel functional genomic screen presented here therefore detects new eukaryotic inhibitors with different chemical structures, kinetics, and predicted modes of actions.
authors.affiliation: School of Biotechnology and Biomolecular Sciences and Centre for Marine Bio-Innovation, University of New South Wales, Sydney 2052, New South Wales, Australia.
authors.forename: Francesco
authors.initials: F
authors.lastname: Ballestriero
authors.forename: Torsten
authors.initials: T
authors.lastname: Thomas
authors.forename: Catherine
authors.initials: C
authors.lastname: Burke
authors.forename: Suhelen
authors.initials: S
authors.lastname: Egan
authors.forename: Staffan
authors.initials: S
authors.lastname: Kjelleberg
mesh_terms: D000818:Animals; D000871:Anthelmintics / Q000378:metabolism* / Q000494:pharmacology*; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D001427:Bacterial Toxins / Q000235:genetics / Q000633:toxicity; D017173:Caenorhabditis elegans / Q000187:drug effects* / Q000502:physiology; D004353:Drug Evaluation, Preclinical / Q000379:methods*; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D057166:High-Throughput Screening Assays / Q000379:methods; D031161:Pseudoalteromonas / Q000235:genetics* / Q000378:metabolism*; D016019:Survival Analysis
chemical_list: D000871:Anthelmintics; D001426:Bacterial Proteins; D001427:Bacterial Toxins