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Caenorhabditis elegans is a popular organism for aging research owing to its highly conserved molecular pathways, short lifespan, small size, and extensive genetic and reverse genetic resources. Here we describe the WormBot, an open-source robotic image capture platform capable of conducting 144 parallel C. elegans survival and behavioral phenotyping experiments. The WormBot uses standard 12-well tissue culture plates suitable for solid agar media and is built from commercially available robotics hardware. The WormBot is controlled by a web-based interface allowing control and monitoring of experiments from any internet connected device. The standard WormBot hardware features the ability to take both time-lapse bright field images and real-time video micrographs, allowing investigators to measure lifespan, as well as heathspan metrics as worms age. The open-source nature of the hardware and software will allow for users to extend the platform and implement new software and hardware features. This extensibility, coupled with the low cost and simplicity of the system, allows the automation of C. elegans survival analysis even in small laboratory settings with modest budgets. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1007/s11357-019-00124-9) contains supplementary material, which is available to authorized users.

The goal of the Caenorhabditis Intervention Testing Program is to identify robust and reproducible pro-longevity interventions that are efficacious across genetically diverse cohorts in the Caenorhabditis genus. The project design features multiple experimental replicates collected by three different laboratories. Our initial effort employed fully manual survival assays. With an interest in increasing throughput, we explored automation with flatbed scanner-based Automated Lifespan Machines (ALMs). We used ALMs to measure survivorship of 22 Caenorhabditis strains spanning three species. Additionally, we tested five chemicals that we previously found extended lifespan in manual assays. Overall, we found similar sources of variation among trials for the ALM and our previous manual assays, verifying reproducibility of outcome. Survival assessment was generally consistent between the manual and the ALM assays, although we did observe radically contrasting results for certain compound interventions. We found that particular lifespan outcome differences could be attributed to protocol elements such as enhanced light exposure of specific compounds in the ALM, underscoring that differences in technical details can influence outcomes and therefore interpretation. Overall, we demonstrate that the ALMs effectively reproduce a large, conventionally scored dataset from a diverse test set, independently validating ALMs as a robust and reproducible approach toward aging-intervention screening. Electronic supplementary material The online version of this article (10.1007/s11357-019-00108-9) contains supplementary material, which is available to authorized users.

Caenorhabditis elegans (C. elegans) lifespan assays constitute a broadly used approach for investigating the fundamental biology of longevity. Traditional C. elegans lifespan assays require labor-intensive microscopic monitoring of individual animals to evaluate life/death over a period of weeks, making large-scale high throughput studies impractical. The lifespan machine developed by Stroustrup et al. (2013) adapted flatbed scanner technologies to contribute a major technical advance in the efficiency of C. elegans survival assays. Introducing a platform in which large portions of a lifespan assay are automated enabled longevity studies of a scope not possible with previous exclusively manual assays and facilitated novel discovery. Still, as initially described, constructing and operating scanner-based lifespan machines requires considerable effort and expertise. Here we report on design modifications that simplify construction, decrease cost, eliminate certain mechanical failures, and decrease assay workload requirements. The modifications we document should make the lifespan machine more accessible to interested laboratories.

Genome instability is a hallmark of aging and contributes to age-related disorders such as progeria, cancer, and Alzheimer’s disease. In particular, nuclear quality control mechanisms and cell cycle checkpoints have generally been studied in young cells and animals where they function optimally, and where genomic instability is low. Here, we use single cell imaging to study the consequences of increased genomic instability during aging, and identify striking age-associated genome missegregation events. During these events the majority of mother cell chromatin, and often both spindle poles, are mistakenly sent to the daughter cell. This breakdown in mitotic fidelity is accompanied by a transient cell cycle arrest that can persist for many hours, as cells engage a retrograde transport mechanism to return chromosomes to the mother cell. The repetitive ribosomal DNA (rDNA) has been previously identified as being highly vulnerable to age-related replication stress and genomic instability, and we present several lines of evidence supporting a model whereby expansion of rDNA during aging results in nucleolar breakdown and competition for limited nucleosomes, thereby increasing risk of catastrophic genome missegregation.