Khamis, Noel et al. (2017) International Worm Meeting "Effects of the anti-microbial agent triclosan on C. elegans survival and behavior."

Khamis, Noel, Myers, Edith, Hoffmann, William, Favetta, Amanda

[International Worm Meeting, 2017]

Triclosan is an antimicrobial agent currently found in products such as soaps and toothpastes. Triclosan has been found to alter endocrine function, development, and lifespan in animals ranging from mollusks to mammals. We are using C. elegans as a system to understand how triclosan may be acting. We have found that triclosan affects C. elegans survival, killing them in a dose-dependent manner. Sublethal concentrations of triclosan have a significant effect on C. elegans movement and egg-laying behavior. Using egg in worm assays, staged egg assays and brood size assays, we have found that triclosan affects egg-laying by decreasing egg production, while at the same time increasing the time eggs are retained before they are laid. Triclosan also appears to affect locomotion in an unc-68 dependent manner. unc-68 encodes a worm ryanodine receptor ortholog. Ryanodine receptors have been implicated in the mode of triclosan action in mouse cardiac and skeletal muscle (Cherednichenko et al. 2012). We are interested in determining the pathways involved in the effect of triclosan on survival and egg development. Cherednichenko G, Zhang R, Bannister RA, et al. (2012). PNAS 109: 14158-14163.

H Van Luenen et al. (1999) International C. elegans Meeting "World-wide worm SNPs: Dissecting the molecular evolution of the species using a high density SNP map"

R Plasterk, R Koch, H Van Luenen

[International C. elegans Meeting, 1999]

We would like to reconstruct the history of the C. elegans species at the genome level, therefore we sampled the genomes of four natural isolates (strain CB4857 isolated in Claremont, California, RC301 from Freiburg, Germany, TR403 from Madison, Wisconsin and AB1 from Adelaide, Australia) for single nucleotide polymorphisms (SNPs). Random genomic DNA fragments from the 4 strains were shotgun cloned and sequenced. There was no selection for transcribed or non-transcribed regions of the genome. In total we sequenced 1572 clones resulting in over 1 Mb of sequence information. The sequences are compared to the canonical Bristol N2 sequence to ask the question whether the clone maps to a unique sequence, and -if so- whether it contains polymorphisms. Once a SNP is identified we check other strains for the presence of the same polymorphism by PCR amplification and sequence analysis. In an initial experiment we found approximately one SNP per 3000 bp sequenced. The SNPs are randomly spread over the genome. Based on these observations we expect to find approximately 500 SNPs, one in every 200 kb. In the initial experiment we found, as expected, that several SNPs initially detected in one strain were also present in some but not all other strains. For example: a T in the Australian AB1, is a G at the same position in Bristol N2 in cosmid K10D2 at position 27946, and we found it to be like AB1 in the Californian CB4857 strain and the German RC301 strain, while the TR403 strain from Wisconsin resembles the Bristol N2 strain. Thus different patches of the genome have different ancestors. With our high density SNP map we will generate a genome map for each isolate which will show how each genome is patched together from a limited set of parental strains. The SNP's will be added to ACeDB, and can also be used as markers on the genetic map. They can be recognised by PCR followed by sequencing, but we also found that the SNPs we looked at could be visualised by SSCP analysis. We thank Jane Rogers and Amanda McMurray for their assistance in sequencing the clones.