Project description:We have investigated the transcriptomic response of the model nematode Caenorhabditis elegans to ivermectin (IVM); an important anthelmintic for human and animal parasite control. The transcriptomic response of the mutant strain DA1316 avr-14(ad1302); avr-15(ad1250); glc-1(pk54), which is highly resistant to ivermectin due to null mutations in three glutamate-gated chloride channel subunits, was examined. Despite the resistant nature of this strain, pharyngeal pumping rate was decreased following 4 hrs exposure to 100ng/ml and 1μg/ml ivermectin resulting in significant change in the expression level of genes associated with a fasting response.
Project description:We have investigated the transcriptomic response of the model nematode Caenorhabditis elegans to ivermectin (IVM); an important anthelmintic for human and animal parasite control. The transcriptomic response of the mutant strain DA1316 avr-14(ad1302); avr-15(ad1250); glc-1(pk54), which is highly resistant to ivermectin due to null mutations in three glutamate-gated chloride channel subunits, was examined. Despite the resistant nature of this strain, pharyngeal pumping rate was decreased following 4 hrs exposure to 100ng/ml and 1?g/ml ivermectin resulting in significant change in the expression level of genes associated with a fasting response. Matched cultures of synchronised C. elegans were grown to L4 stage on standard NGM plates with an OP50 bacterial lawn. The nematodes were then transferred to NGM plates containing 100ng/ml ivermectin, 1?g/ml ivermectin, or DMSO excipient only (control) for 4 hours. RNA was extracted from five biological replicates including controls for both the 100ng/ml ivermectin and 1?g/ml ivermectin experiments and hybridised to Affymetrix arrays.
Project description:Ivermectin (IVM) is a cornerstone of nematode control. However, its efficacy is increasingly compromised by emerging resistance in targets parasites. Here, we investigated these mechanisms in three independently evolved Caenorhabditis elegans lineages exposed to stepwise ivermectin selection. Remarkably, these populations, although distinct, converged over time to a comparable and stabilized high level of IVM resistance. RNAseq analysis across lineages revealed a conserved enrichment for ciliary/neuronal pathways including genes expressed in amphid/phasmid, indicating remodeling of the chemosensory/ciliary network as resistance intensifies. All resistant lines also converged on the dye-filling defective (Dyf) phenotype that emerged during selection at stages coinciding with sharp gains in ivermectin tolerance, implicating amphid structure/function in the establishment of durable resistance. Our results support a two-phase associative model in which early PGP-mediated tolerance precedes the emergence of ciliary/amphidial signatures and a Dyf phenotype during selection that durably reduces susceptibility.
Project description:Young adult fer-15;fem-1 Caenorhabditis elegans were infected with Staphylococcus aureus for 8 h to determine the transcriptional host response to Staphylococcus aureus. Analysis of differential gene expression in C. elegans young adults exposed to two different bacteria: E. coli strain OP50 (control), wild-type Staphylococcus aureus RN6390. Samples were analyzed at 8 hours after exposure to the different bacteria. These studies identified C. elegans genes induced by pathogen infection. Keywords: response to pathogen infection, innate immunity, host-pathogen interactions
Project description:Young adult N2 Caenorhabditis elegans were infected with Enterococcus faecalis or Enterococcus faecium for 8 h to determine the transcriptional host response to each enterococcal species. Analysis of differential gene expression in C. elegans young adults exposed to four different bacteria: heat-killed Escherichia coli strain OP50 (control), wild-type E. faecalis MMH594, wild-type E. faecium E007, or Bacillus subtilis PY79 (sigF::kan). Samples were analyzed at 8 hours after exposure to the different bacteria. These studies identified C. elegans genes induced by pathogen infection. Brain-heart infusion agar plates (10 ug/ml kanamycin) were used.