Kinser, H. et al. (2017) International Worm Meeting "A screen to identify miRNA predictors of individual lifespan in C. elegans."

Kinser, H., Pincus, Z.

[International Worm Meeting, 2017]

Genetically identical C. elegans individuals reared in highly uniform environments nonetheless exhibit widely different lifespans. We propose that early-life differences in the expression of key regulatory genes direct otherwise identical individuals into different gene expression states, resulting in profound differences in lifespan. To identify such regulators, we screened miRNA::GFP reporters to identify those whose expression correlates with lifespan in wild-type C. elegans individuals. We developed a novel series of high-throughput, automated methods to overcome the technical challenges of this approach, which requires observation of large numbers of individuals to generate statistical significance while maintaining single-animal resolution for longitudinal measures of gene expression and lifespan. Briefly, we deposited adult animals into 384 well plates, one per well, and acquired fluorescence images of each individual. We maintained the animals in liquid culture and conducted daily whole-plate time-lapse imaging with modified flatbed scanners to measure the lifespans of many individuals in parallel. We performed multiple rounds of screening with 48 different miRNA::GFP reporter strains and identified 8 whose expression is significantly correlated with lifespan. We have thus far validated one of the hits from the screen, miR-63, in a single-animal solid culture system, showing that early-life expression of this miRNA is predictive of individual lifespan in multiple contexts. By continuing to characterize these miRNAs and their downstream targets, we will define gene expression states associated with longevity and the broader pathways and networks involved in determination of individual lifespan.

Thomas JH et al. (1994) Worm Breeder's Gazette "lin-36, a Class B Synthetic Multivulva Gene, Encodes a Novel Protein"

Thomas JH, Horvitz HR

[Worm Breeder's Gazette, 1994]

lin-36, a Class B Synthetic Multivulva Gene, Encodes a Novel Protein Jeffrey H. Thomas and H. Robert Horvitz, HHMI, Dept. Biology, MIT, Cambridge, MA 02139, USA

Laird, N. et al. (2019) International Worm Meeting "A Suite of Tools to Measure Spatiotemporal Patterns in C. elegans."

Pincus, Z., Laird, N., Kinser, H.

[International Worm Meeting, 2019]

Quantitative analysis of spatial (and space-time) patterns in brightfield and fluorescent images of C. elegans is made difficult by the flexible and deformable nature of this organism. In order to compare, for example, fluorescent reporter expression between different individuals, the differences in posture between those individuals must first be taken into account. We have developed a suite of tools to perform these tasks. We have devised automated and manual methods to identify C. elegans from brightfield images and fit a nose-to-tail "centerline", allowing us to transform image pixels from the laboratory frame of reference into a standard "worm frame of reference". In this reference frame, brightfield and fluorescence patterns can be directly compared across individuals, or within an individual over time. Previous approaches for analyzing spatial patterns have relied on high-resolution imaging with a set of nuclear labels as fiducial markers for aligning expression patterns between individuals at a cellular resolution. In contrast, we have developed tools to perform lower-resolution analysis on whole-body image patterns with just a few (or no) manually or automatically-identified anatomical landmarks. The system works in several phases: 1) computationally straighten the curved worm body in the image to bring an image into the worm reference frame, 2) map the image to a standardized "unit worm" shape and size, optionally using anatomical landmarks to account for worm-to-worm variation in longitudinal compression, and 3) use these registered images to compare fluorescent expression patterns or brightfield measures across different images. Defining an anatomical atlas on the "unit worm" coordinate system allows coarse anatomical regions to be easily identified and compared across images. We demonstrate several applications of these tools to spatial analysis of fluorescence patterns, including analysis of pre-defined anatomical regions and data-driven approaches to identify population trends in fluorescence. We also demonstrate that distortions produced by transformation of images into a "unit worm" reference frame are minimal and do not alter the results of downstream analyses. Moreover by identifying the posture of individuals in images, our tools also enable simple studies of growth, tissue scaling, movement, and posture throughout development and aging. These tools are available as open-source software packages.

Mosley, M. et al. (2019) International Worm Meeting "Uncovering Gene Expression Programs that Determine Individual Lifespan in C. elegans."

Kinser, H., Mosley, M., Pincus, Z.

[International Worm Meeting, 2019]

A longstanding mystery within the field of aging is the origin of an individual's lifespan. The traditional explanations of genes and environment are insufficient: even within an isogenic population of C. elegans reared in a homogenous environment, lifespan is highly variable. We hypothesize that this variability is caused by distinct patterns of gene expression which arise early in life due, for instance, to stochastic heterogeneity in the activity of key developmental regulators. These differences in transcriptional programs would then lead individuals to commit to long- or short-lived fates. In support of this hypothesis, we have found that, early in adulthood, a fluorescent reporter for the developmental timing microRNA lin-4 is highly predictive of future lifespan. Expression of lin-4p::GFP appears to take on stable "high" or "low" states in long- and short-lived cohorts, respectively, consistent with a process whereby individuals commit to distinct future fates. In order to characterize the gene-regulatory network that leads some individuals to persistent high vs. low lin-4p::GFP states, we have developed a microfluidic device to physically separate individuals by fluorescence intensity. Through transcriptomic analysis of these differently-fated cohorts, we have defined distinct gene expression profiles that appear to drive variability in lifespan within a homogenous, wild type population. Specifically, we have found genes relating to insulin signaling, nutrient sensing, and innate immunity which likely modulate lin-4p::GFP expression and individual lifespan.

Sun J et al. (2013) Exp Parasitol "Parasitism of secondary-stage juvenile of Heterodera glycines and four larva stages of Caenorhabditis elegans by Hirsutella spp."

Sun J, Xie H, Xiang M, Liu X, Qiu J

[Exp Parasitol, 2013]

The fungi Hirsutella rhossiliensis and Hirsutella minnesotensis generally parasitize only plant-parasitic nematodes in nature but parasitize the bacterivorous nematode Caenorhabditis elegans on agar plates. To establish a model system for studying the interaction between fungi and nematodes, we compared the parasitism of the first- to fourth-stage larvae (L1-L4) of C. elegans and second-stage juvenile (J2) of Heterodera glycines by twenty isolates of Hirsutella spp. Although parasitism differed substantially among isolates, both H. minnesotensis and H. rhossiliensis parasitized a higher percentage of H. glycines J2s than of C. elegans larvae. Parasitism of C. elegans L1s was correlated with parasitism of H. glycines J2s. Parasitism of C. elegans by H. rhossiliensis and H. minnesotensis was negatively correlated with larva size and motility, i.e., parasitism was higher for the younger stages. The C. elegans L1 is recommended for studying parasitism of nematodes by H. rhossiliensis and H. minnesotensis.

Fei YJ et al. (2000) J Biol Chem "A novel H(+)-coupled oligopeptide transporter (OPT3) from Caenorhabditis elegans with a predominant function as a H(+) channel and an exclusive expression in neurons."

Leibach FH, Romero MF, Krause MW, Huang W, Ganapathy V, Fei YJ, Liu JC

[J Biol Chem, 2000]

We have cloned and functionally characterized a novel, neuron-specific, H(+)-coupled oligopeptide transporter (OPT3) from Caenorhabditis elegans that functions predominantly as a H(+) channel. The opt3 gene is approximately 4.4 kilobases long and consists of 13 exons. The cDNA codes for a protein of 701 amino acids with 11 putative transmembrane domains. When expressed in mammalian cells and in Xenopus laevis oocytes, OPT3 cDNA induces H(+)-coupled transport of the dipeptide glycylsarcosine. Electrophysiological studies of the transport function of OPT3 in Xenopus oocytes show that this transporter, although capable of mediating H(+)-coupled peptide transport, functions predominantly as a H(+) channel. The H(+) channel activity of OPT3 is approximately 3-4-fold greater than the H(+)/peptide cotransport activity as determined by measurements of H(+) gradient-induced inward currents in the absence and presence of the dipeptide using the two-microelectrode voltage clamp technique. A downhill influx of H(+) was accompanied by a large intracellular acidification as evidenced from the changes in intracellular pH using an ion-selective microelectrode. The H(+) channel activity exhibits a K(0.5)(H) of 1.0 microM at a membrane potential of -50 mV. At the level of primary structure, OPT3 has moderate homology with OPT1 and OPT2, two other H(+)-coupled oligopeptide transporters previously cloned from C. elegans. Expression studies using the opt3::gfp fusion constructs in transgenic C. elegans demonstrate that opt3 gene is exclusively expressed in neurons. OPT3 may play an important physiological role as a pH balancer in the maintenance of H(+) homeostasis in C. elegans.

Imadzu H et al. (1994) Worm Breeder's Gazette "Two Tropomyosins Expressed in Body Wall and the Third Did In Pharynx of Caenorhabditis elegans"

Kagawa H, Sakube Y, Imadzu H

[Worm Breeder's Gazette, 1994]

TWO TROPOMYOSINS EXPRBSSBD IN BODY WALL AND THE THIRD DID IN PHARYNX OF CAENORHABDDITIS ELEGANS. H. Imadzu, Y. Sakube and H. gagawa. Department of Biology, Faculty of Science, Okayama University, Okayama, 700 Japan.

Wilson PA et al. (1982) Parasitology "Strongyloides ratti (homogonic): the time-course of early migration in the generalized host deduced from experiments in lactating rats."

Steven GE, Simpson NE, Wilson PA

[Parasitology, 1982]

Unsuckled mother rats given a 1 h suckling stimulus 3 h after subcutaneous injection of an exact dose of homogonic Strongyloides ratti allow fewer worms to develop in their intestines by day 9 than nulliparous rats (Wilson & Simpson, 1981). This effect is studied in more detail in terms of the length of time between weaning and stimulus (W leads to S) and injection and stimulus (I leads to S). It was observable with a W leads to S of 30 h but this and a period of 5 h were less effective than 24 h. With W leads to S constant at 24 h, significantly more worms developed in mothers when I leads to S was 24 h compared to 3 h and 10 h (P less than 0.005). The data, combined with those from nulliparous controls, are presented as a measure of the change with time of numbers of larvae in that compartment of the system which gives access to the stimulated mammary gland. It is argued that the particular compartment is the local lymph node draining the injection site and that the kinetics deduced are applicable to migration in the rat in general.

Miller DL et al. (2007) Proc Natl Acad Sci U S A "Hydrogen sulfide increases thermotolerance and lifespan in Caenorhabditis elegans."

Miller DL, Roth MB

[Proc Natl Acad Sci U S A, 2007]

Hydrogen sulfide (H(2)S) is naturally produced in animal cells. Exogenous H(2)S has been shown to effect physiological changes that improve the capacity of mammals to survive in otherwise lethal conditions. However, the mechanisms required for such alterations are unknown. We investigated the physiological response of Caenorhabditis elegans to H(2)S to elucidate the molecular mechanisms of H(2)S action. Here we show that nematodes exposed to H(2)S are apparently healthy and do not exhibit phenotypes consistent with metabolic inhibition. Instead, animals exposed to H(2)S are thermotolerant and long-lived. These phenotypes require SIR-2.1 activity but are genetically independent of the insulin signaling pathway, mitochondrial dysfunction, and caloric restriction. These studies suggest that SIR-2.1 activity may translate environmental change into physiological alterations that improve survival. It is interesting to consider the possibility that the mechanisms by which H(2)S increases thermotolerance and lifespan in nematodes are conserved and that studies using C. elegans may help explain the beneficial effects observed in mammals exposed to H(2)S.

Sakube Y et al. (1994) Worm Breeder's Gazette "The Genome Structure and Expression of Promoter/lacZ Fusion Genes of C. elegans Ryanodine Receptor"

Imadzu H, Sakube Y, Kagawa H

[Worm Breeder's Gazette, 1994]

The Genome Structure and Expression of Promoter/lacZ Fusion Genes of the C. elegans Ryanodine Receptor Y. Sakube, H. Imadzu and H. Kagawa, Laboratory of Molecular Biology, Faculty of Science, Okayama University, Okayama, 700 Japan C51918@JPNKUDPC