Antol, Weronika et al. (2022) MicroPubl Biol

Sychta, Karolina, Prokop, Zofia M., Antol, Weronika, Palka, Joanna K., Dudek, Katarzyna

[MicroPubl Biol, 2022]

Caenorhabditis elegans is a model species, increasingly used in experimental evolution studies to investigate such major topics as: maintenance of genetic variation, host-pathogen interaction and coevolution, mutations, life history, evolution of reproductive systems, sexual selection (Gray and Cutter, 2014; Teotnio, Estes, Phillips, and Baer, 2017). Its reproductive system in the wild, known as androdioecy, involves mostly self-fertilization of hermaphrodites and occasionally outcrossing with males, which are generally rare (Stewart and Phillips, 2002). This system can be experimentally changed to dioecy, i.e., obligatory outcrossing, through genetic manipulations (see Table I in Anderson, Morran, and Phillips, 2010; Gray and Cutter, 2014).

Blue, Ben W. et al. (2019) International Worm Meeting "Longevity Over the Counter: Investigating the Effects of Common Dietary Supplements on Aging."

Berry, Faith, Estes, Raja, Blue, Ben W., Pitt, Jason, Kim, Young-Woo, Vayndorf, Elena, Nikjoo, Arash, Kaeberlein, Matt, Pothan, Lincoln

[International Worm Meeting, 2019]

C. elegans has been a workhorse within the field of aging biology due to its short lifespan, easy culturing, and robust genetic tools. However, one major limiting factor in using C. elegans has been that throughput was constrained by the time and effort needed to manually check each worm for signs of life during longitudinal studies. By using the WormBot, a high-throughput robotic image capture platform, we were able to accurately and quickly screen a wide array of compounds for their effects on C. elegans lifespan. A single WormBot can monitor 144 individual experiments at once and, when coupled with an image analysis package, allows for accurate time of death calls. Here we present data generated with the WormBot that includes a screen of compounds from a wide array of natural and synthetic products. Supplements and multivitamin/minerals (MVMs) were a ~36 billion dollar industry in 2014 but are not subject to the same regulatory standards that FDA-approved drugs are. In order to better examine the effects of these widely-used compounds upon the aging process we examined longevity in a wildtype strain of C. elegans (N2) as well as an engineered strain (GMC101) that expresses human A? protein in the body wall muscle. The age-related pathogenesis of the A?-expressing strain is a progressive paralysis. As such, we screened our battery of compounds to determine which compounds have a significant effect on delaying GMC101's A?-associated paralysis. Lastly, using the WormBot's ability to capture video recording alongside time-lapse photography, we examine how each compound affects the healthspan of the different genetic models by using the WormBot's ability to capture high-resolution videos and then analyzing animal motility.

Estes S et al. (2006) Evolution "Variation in pleiotropy and the mutational underpinnings of the G-matrix."

Estes S, Phillips PC

[Evolution, 2006]

The pattern and extent of pleiotropic gene action can contribute substantially to the internal structure and shape of the additive genetic variance-covariance matrix (G)--a key determinant of evolutionary trajectories. We use data from our study (Estes et al. 2004) on the univariate effects of mutation in a mismatch-repair-defective strain, msh-2, of Caenorhabditis elegans to address the impact of increasing levels of selection on the magnitude and pattern of genetic covariance due to new mutations. Mutational covariances between three life-history traits are shown to exhibit a weak pattern of decline with increasing population size (increasing selection), while the orientation of mutational matrices remains reasonably constant. This suggests that mutations with smaller effects on fitness may tend to be slightly more confined in their influence than large-effect mutations (i.e., small-effect mutations reduce the magnitude of covariation between characters), but do not change the direction of this covariation.

Mueller, Louisa et al. (2013) International Worm Meeting "The role of LIN-3 during morphogenesis of the dorsal lumen in the vulva."

Morf, Matthias, Mueller, Louisa, Hajnal, Alex

[International Worm Meeting, 2013]

The hermaphrodite vulva is an excellent organ to identify and study the molecular mechanisms controlling tissue morphogenesis during development. Vulval development is initiated by the anchor cell (AC) in the somatic gonad, which secretes LIN-3 EGF and induces the vulval cell fates in three of the six adjacent vulval precursor cells. After vulval induction, the AC breaches two basal laminae and invades in-between the innermost 1 deg -fated VPC descendants (the VulF cells). AC invasion is important for proper morphogenesis of the dorsal lumen formed by the VulF toroids [1] and to establish the uterine-vulval connection. During vulval morphogenesis, LIN-3 is secreted from the VulF cells to specify the uv1 fate [2]. Here, we investigated another function of LIN-3 produced by VulF during dorsal lumen morphogenesis. Vulva-specific lin-3 RNAi using an rde-1(lf) mutant expressing rde-1(wt) in the Pn.p cells prevented the expansion of the dorsal lumen by the AC. A similar defect in dorsal lumen morphogenesis was observed in egl-38(lf) mutants that do not express LIN-3 in VulF cells [1,3]. Moreover, egl-38(lf) mutants displayed defects in AC polarization. Based on these and further results, we propose that LIN-3 expressed by the VulF cells controls dorsal lumen morphogenesis by polarizing the AC and thus enabling it to migrate in between the VulF cells and expand the dorsal lumen. [1] Estes, K. A. and Hanna-Rose, W. (2009). The anchor cell initiates dorsal lumen formation during C. elegans vulval tubulogenesis. Dev Biol 328, 297-304 [2] Chang, C., Newman, A. P. and Sternberg, P. W. (1999). Reciprocal EGF signaling back to the uterus from the induced C. elegans vulva coordinates morphogenesis of epithelia. Curr Biol 9, 237-46. [3] Rajakumar, V. and Chamberlin, H. M. (2007). The Pax2/5/8 gene egl-38 coordinates organogenesis of the C. elegans egg-laying system. Dev Biol 301, 240-53.

Nelson GA et al. (1984) Worm Breeder's Gazette "untitled."

Nelson GA, Dyer M, Hammen RF

[Worm Breeder's Gazette, 1984]

I've just begun to do some radiobiology using heavy ions from the Berkeley Bevalac accelerator as a way of modeling cosmic rays. NASA is interested in some biological dosimetry for heavy particles such as are encountered in earth orbit on the shuttle. Because of their true track structure, measurements in units such as rads and roentgens have dubious utility. Below are some preliminary results from iron irradiation experiments which looked for twitchers using Don Moerman and Dave Baillie's nicotine trick and some lethals using Raja Rosenbluth's eT1 balancer technique. The particles are highly mutagenic and I hope to eventually describe the types and extents of lesions caused by single particle interactions. An experiment using the BEVALAC accelerator at Lawrence Berkeley Laboratory was carried out on June 17, 1984. The purpose of this experiment was to familiarize us with the operation of the facility and to demonstrate the proof of concept that mutations could be induced in C. elegans using energetic heavy ions from the accelerator. Several tests were carried out but two are especially relevant here: 1) the induction of 'twitcher' mutants in gene unc-22 and, 2) the induction of lethal mutations in cross-over suppressed regions of chromosomes III and V using a reciprocal translocation strain. We were able to isolate 4 unc-22 mutants from 1965 N2 worms with gonads containing nominally 4, 10 and 30 cells with equivalent radiation doses of 30.02, 3.24 and 228.9 rads respectively. Several instances of male 'jackpots' were also noted. (A male 'jackpot' is the appearance of large groups of F1 males in broods of virgin hermaphrodites presumably due to induced X-chromosome loss; typical jackpots were 7 to 17 males per plate of 10 PO's whereas 0, 1 or 2 is normal). 6 lethal mutations and one long mutation were isolated from 96 adult worms tripley heterozygous for dpy-18 III, unc-46 V and the reciprocal translocation eT1(III;V) using an equivalent radiation dose of 3D.n2 rads. The type of radiation used was a beam of completely ionized iron particles having an energy of 445 MeV per nucleon or a total of 24.85 GeV per particle. The linear energy transfer of these particles was determined to be 198 KeV/micron and particles were delivered in pulses such that total fluence varied from about 10+E5 to 10+E7 particle tracks per cm2. Radiation characteristics were determined by Dr. E.V. Benton using CR-39 plastic radiation detector foils. We concluded that heavy ions are highly mutagenic in C. elegans and that the assays proposed in this proposal are capable of detecting genetic lesions induced by them. Work is in progress to determine the locations and nature of the new mutations. Confirming studies using alpha particles from Polonium - 210 also demonstrated the effectiveness of high LET particles. Mutations in unc-22 as well as several 'dumpy' and 'cell lineage defective' genes were induced with alpha particles using 1st stage larvae or dauer larvae as targets. The accompanying figure summarizes the BEVALAC results. [No accompanying figure]