[
International Worm Meeting,
2021]
Neurodegenerative diseases predominantly affect older cohorts, but the first misfolding processes occur earlier in life, prior to diagnosis. Therefore, the ability to monitor health prior to the onset of severe symptoms will be informative in the search for preventative interventions and in understanding disease onset. There are several C. elegans models of neurodegeneration but manual assays are subjective, labour intensive and provide binary data at single time points per animal - namely time of paralysis. An automated imaging system to monitor worm movement can assist by simultaneously revealing in-depth movement data unavailable to manual methods and scaling to study hundreds of plates of animals more easily. We have developed a technology that monitors plates of 6 cm petri dishes, with 30 worms on each. Using strains expressing polyglutamine tracts and amyloid-beta, we show that the presence of these transgenes is associated with early-life movement decline. Furthermore, there are differences in decline pattern dependent on whether the polyQ tract is expressed in body wall muscle or pan-neuronally, and on what treatments are used to prevent progeny such as FUdR or temperature sensitive sterile backgrounds. These findings allow the development of a robust system on which to screen mutants and pharmaceutical therapies. Our particular interest is drugs that influence E. coli as a model for microbiome interventions. We have found that inhibiting bacterial folate synthesis using sulfamethoxazole (SMX) extends C. elegans lifespan and healthspan, and here we also show the effect of SMX on various neurodegenerative models. This approach therefore becomes a model of gut microbiome-host interaction which can streamline the selection of therapies for further testing on mammal models in the drug discovery pipeline.
[
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.