Dao, Chris et al. (2017) International Worm Meeting "Development of a high-statistics, three dimensional imaging system for C. elegans under magnetic and chemical stimuli."

Arisaka, Katushi, David, Angela, Vincent, Nitin, Thatcher, Joseph, Chow, Aaron, Wang, Charles, Dao, Chris, Du, Angela, Alberto, Jasmine, Li, Lina

[International Worm Meeting, 2017]

In contrast to previous behavioral experiments limited to two dimensional surfaces, we extended the study of C. elegans into three dimensional environments to observe the resulting unconstrained motion. While research has been initiated towards single worm, high magnification tracking, this has limited practicality in terms of gathering a large number of statistics with bulk behavior of many worms simultaneously. Incorporating stimuli allows for a new, more thorough examination of motion and environmental interaction, extending inquiry beyond simple free motion. Previously performed, two dimensional results suggest hypotheses, which may serve as limiting-case projections of greater trends in three dimensional space. A novel, cost effective system was developed to image C elegans' behavior over a period of 30 to 60 minutes using time lapse acquisition. The setup consists of three, perpendicularly oriented DSLR cameras, synchronized via the open source, MIT developed DigiCam control software and illuminated with lowly-invasive, conical, red LED light sources. Samples consisted of N2 type worms embedded in the center of 2% porcine gelatin (4 to 5 cm) quartz cuvettes. Each camera had an affixed aperture to elongate its depth of field, promoting focus throughout the volume of the cubes. In addition to free motion studies, three sets of Helmholtz coils (with axes coinciding with the cameras' optical axes) were utilized to generate a uniform magnetic field at the location of the sample. NaCl concentration gradients throughout the gelatin were also simulated and created for three dimensional chemotaxis experiments. Numerous free motion trials have been conducted alongside magnetic field experiments of field magnitude ranging from 0 Gauss (cancelling the geomagnetic field) to 10 Gauss. Using this data, analysis software tools were developed in MATLAB in order to extract the center of mass trajectory of worms navigating the gelatin, enabling further quantification of motional trends such as the worms' velocities and distributions of initial and final positions. While preliminary results for free motion (with chemical attractants) appear to reflect standard biased random motion, positive verification of magnetic field trials remains elusive.

Dernburg AF et al. (1997) International C. elegans Meeting "Cytological investigation of homologous pairing during meiotic prophase"

Dernburg AF, Villeneuve AM

[International C. elegans Meeting, 1997]

Pairing and recombination between homologous chromosomes are essential for their faithful segregation during the first meiotic division. The mechanisms leading to homologous chromosome pairing and synapsis are still only poorly understood in any experimental organism. C. elegans provides a highly advantageous model system in which genetic and cytological approaches can be combined to study this process. We are developing tools and methods to enable us to examine chromosome pairing in the light microscope in order to address several specific questions: Do special sites on each chromosome (particularly the genetically-defined !pairing centers!) become associated earlier than others? Do chromosome rearrangements that act as crossover suppressors disrupt homologous pairing as dramatically as genetic evidence seems to suggest? Are gene products that are required for meiotic recombination associated with particular regions of the chromosomes? To answer these and other questions, we are using several approaches, including fluorescence in situ hybridization (FISH) methods, and labeling of chromosomes in living worms using the GFP-Lac repressor binding method developed by Aaron Straight, Andrew Murray, and Andy Belmont for other experimental systems. By applying high-resolution 3-dimensional microscopy, we hope to obtain a better understanding of rules governing the organization and interaction of chromosomes in the meiotic prophase nucleus.

Thomas C et al. (2023) Nat Commun "A naturally occurring polyacetylene isolated from carrots promotes health and delays signatures of aging."

Lamers G, Ristow M, Carreira EM, Fischer F, Erni R, Thomas C, Grigolon G, Wu JY, Zarse K, Mitchell SJ

[Nat Commun, 2023]

To ameliorate or even prevent signatures of aging in ultimately humans, we here report the identification of a previously undescribed polyacetylene contained in the root of carrots (Daucus carota), hereafter named isofalcarintriol, which we reveal as potent promoter of longevity in the nematode C. elegans. We assign the absolute configuration of the compound as (3 S,8 R,9 R,E)-heptadeca-10-en-4,6-diyne-3,8,9-triol, and develop a modular asymmetric synthesis route for all E-isofalcarintriol stereoisomers. At the molecular level, isofalcarintriol affects cellular respiration in mammalian cells, C. elegans, and mice, and interacts with the α-subunit of the mitochondrial ATP synthase to promote mitochondrial biogenesis. Phenotypically, this also results in decreased mammalian cancer cell growth, as well as improved motility and stress resistance in C. elegans, paralleled by reduced protein accumulation in nematodal models of neurodegeneration. In addition, isofalcarintriol supplementation to both wild-type C57BL/6NRj mice on high-fat diet, and aged mice on chow diet results in improved glucose metabolism, increased exercise endurance, and attenuated parameters of frailty at an advanced age. Given these diverse effects on health parameters in both nematodes and mice, isofalcarintriol might become a promising mitohormesis-inducing compound to delay, ameliorate, or prevent aging-associated diseases in humans.

Baek HK et al. (2016) J Vet Sci "Neuronal maturation in the hippocampal dentate gyrus via chronic oral administration of Artemisa annua extract is independent of COX-2 signaling pathway in the diet-induced obesity (DIO) mice model."

Hwang IK, Kim PS, Song JA, Choi DH, Yi SS, Kim SJ, Seo HS, Kim DE, Park SK, Oh SI, Song KD, Baek HK

[J Vet Sci, 2016]

Recently, we reported that Artemisia annua (AA) has anti-adipogenic properties in vitro and in vivo. Reduction of adipogenesis by AA treatment may dampen systemic inflammation and protect neurons from cytokine-induced damage. Therefore, the present study was performed to assess whether AA increases neuronal maturation by reducing inflammatory responses, such as those mediated by COX-2. Mice were fed normal chow or a high-fat diet with or without chronic daily oral administration of AA extract (0.2g/10mL/kg) for 4 weeks; then, changes in their hippocampal dentate gyri were measured with immunohistochemistry/immunofluorescence staining for BrdU, DCX, and NeuN, markers of neuronal maturation, and a quantitative Western blot for COX-2 and Iba-1, in order to assess correlations between systemic inflammation (Il-6) and food type. Additionally, we tested the effect of AA in an Alzheimer's disease model of C. elegans and uncovered a potential benefit. In the present study, we show that chronic AA dosing significantly increases neuronal maturation, particularly in the high-fat diet group. This effect was seen in the absence of any changes in COX-2 levels in mice given the same type of food, pointing to the possibility of alternate anti-inflammatory pathways in the stimulation of neurogenesis and neuro-maturation in a background of obesity.

Rajcic D et al. (2023) Biomolecules "Supplementing L-Citrulline Can Extend Lifespan in C. elegans and Attenuate the Development of Aging-Related Impairments of Glucose Tolerance and Intestinal Barrier in Mice."

Brandt A, Baumann A, Rajcic D, Bergheim I, Camarinha-Silva A, Hernandez-Arriaga A, Kromm F, Staltner R

[Biomolecules, 2023]

L-Citrulline (L-Cit) is discussed to possess a protective effect on intestinal barrier dysfunction but also to diminish aging-associated degenerative processes. Here, the effects of L-Cit on lifespan were assessed in <i>C. elegans</i>, while the effects of L-Cit on aging-associated decline were determined in C57BL/6J mice. For lifespan analysis, <i>C. elegans</i> were treated with &#xb1;5 mM L-Cit. Twelve-month-old male C57BL/6J mice (<i>n</i> = 8-10/group) fed a standard chow diet received drinking water &#xb1; 2.5 g/kg/d L-Cit or 5 g/kg/d hydrolyzed soy protein (Iso-N-control) for 16 or 32 weeks. Additionally, 4-month-old C57BL/6J mice were treated accordingly for 8 weeks. Markers of senescence, glucose tolerance, intestinal barrier function, and intestinal microbiota composition were analyzed in mice. L-Cit treatment significantly extended the lifespan of <i>C. elegans</i>. The significant increase in markers of senescence and signs of impaired glucose tolerance found in 16- and 20-month-old control mice was attenuated in L-Cit-fed mice, which was associated with protection from intestinal barrier dysfunction and a decrease in NO₂^- levels in the small intestine, while no marked differences in intestinal microbiota composition were found when comparing age-matched groups. Our results suggest that pharmacological doses of L-Cit may have beneficial effects on lifespan in <i>C. elegans</i> and aging-associated decline in mice.

Mavji N Patel et al. (2001) International C. elegans Meeting "Evolution of germ-line signals that regulate growth and ageing in nematodes"

Armand M Leroi, Constantina Karageorgi, Christopher G Knight, Mavji N Patel

[International C. elegans Meeting, 2001]

One of the least understood aspects of animal development is how growth and body size are regulated 1,2 . Here we show that a signal from the germ-line represses growth in the nematode Caenorhabditis elegans . Laser-microbeam ablation of cells that give rise to the germ-line causes adults to become giant. Ablation of these cells in self-sterile mutant worms also causes gigantism suggesting that the germ-line represses growth because it is the source of a growth-antagonizing signal rather than a sink of resources required for reproduction. The C. elegans germ-line also emits a signal that represses longevity 3 . This longevity-repressing signal requires the activity of DAF-16, a forkhead/winged-helix transcription factor 3 , but we find that that the growth-repressing signal does not. The growth-repressing signal also does not require the activity of DBL-1, a TGF-beta-related protein that promotes growth in worms 4,5 . By ablating the germ-line precursors of other species of free-living nematodes we found that both the growth-repressing and longevity-repressing signals are evolutionarily variable. Some species have both, others have just one or the other. We suggest that variation in germ-line signaling contributes to body size and life-history diversity in the nematodes. 1. I, Conlon, M. Raff, Cell 96, 235 (1999). 2. S. J. Day, P. A. Lawrence, Development 127, 2977 (2000). 3. H. Hsin, C. Kenyon, Nature 399 , 362 (1999). 4. K. Morita, K. L. Chow, N. Ueno, Development 126, 1337 (1999). 5. Y. Suzuki et al ., Development 126, 241 (1999).

W.K. So et al. (2006) European Worm Meeting "Sex pheromone production in dioecious nematodes and the perception pathway delineated by genetics"

W.S. Yeung, M.Y. Wu, C.M. Chan, W.K. So, K.L. Chow

[European Worm Meeting, 2006]

W.K. So, C.M. Chan, M.Y. Wu, W.S. Yeung and K.L. Chow. In dioecious nematodes, finding the mating partner and successful mating is instrumental to their reproductive success. To ensure these tasks are accomplished, sex pheromone production is a common strategy adopted in the nematode world. In Caenorhabditis remanei, a dioecious species, a sex-specific attractant was identified to be produced by females for attracting males. In this study, we focus on four areas of characterization, the properties of the pheromone, its regulatory production in female, male perception and species specification. In the characterization part, our GC-MS analysis result identifies two candidate chemicals in the samples, the exact identity of which will be confirmed by chemical synthesis coupled with bioassays. These attractant substances are produced under tight developmental control in the gonad as confirmed by laser ablation of gonadal progenitor cells in different combination. Their activity could be abolished by mating with males. Based on our pervious results, the males of the androdioecious can be attracted by this sex pheromone. So for the male perception part, we employed males from various Caenorhabditis elegans mutants with defects in cell lineage or molecular function to delineate the perception pathway. Our results show that two different sensory neurons and an interneuron are required. Moreover, a signaling process dependent of G protein coupled receptor is crucial for the pheromone perception, where modulation by other molecular components has been observed. Hypothesis suggesting a conservation of the pheromone perception pathway across different species will be tested using chemo-attraction assay on con-specific and hetero-specific combination of testing animals. (The project is funded by Research Grant Council, Hong Kong.)

Yang T et al. (2019) J Ethnopharmacol "Ultrasonicated sour Jujube seed flavonoids extract exerts ameliorative antioxidant capacity and reduces A-induced toxicity in Caenorhabditis elegans."

Zhang Y, Li J, Lin T, Xie J, Yang T, Zhou A, Fang L

[J Ethnopharmacol, 2019]

ETHNOPHARMACOLOGICAL RELEVANCE: Sour Jujube seed from Ziziphus jujuba Mill. var. Spinosa (Bunge) Hu ex H. F. Chow is a traditional Chinese herb. It was demonstrated with significant activities in anti-depression and antioxidant by numerous pharmacological studies. Flavonoids is one of the main constituents in sour Jujube seed. AIM OF THE STUDY: The aim of this study was to propose a green ultrasound-assisted extraction (UAE) process of flavonoids from sour Jujube seed. MATERIALS AND METHODS: The extraction parameters were investigated and optimized using single factor experiments, Plackett-Burman design (PBD) and response surface methodology (RSM). Moreover, a comparative analysis between ultrasound-assisted extraction and heat reflux extraction was performed to verify the ameliorating effects of ultrasound-assisted extraction on the flavonoids yield, the composition, antioxidant capacities in vitro and ROS scavenging capacity in PC12cells. Meanwhile, the effects of flavonoids extract (FE) on A transgenic Caenorhabditis elegans (GMC101) behavior were investigated. RESULTS: The optimal extracting conditions of total flavonoids were as follows: ethanol concentration 70.60 (v/v%), liquid-solid ratio 15.02:1mL/g, ultrasonic power 404W, extraction time 60.03min. The highest extraction yield was 1.59%. When compared to Heat reflux extraction (HRE) that only has gained a yield of 1.356%. Approximately, the UAE method was able to increase the yield by 17.11%. Moreover, FE extracted by UAE displayed larger capacity of scavenging ABTS, DPPH, superoxide, and hydroxyl radicals and reducing the level of ROS accumulation in PC12cells, suggesting the biological functions of these compounds could be also better protected under UAE conditions. Furthermore, FE could also increase the chemotaxis and heat stress resistance ability, delay the paralysis and extend the lifespan of Caenorhabditis elegans. CONCLUSION: UAE is a green and efficient technique for the preparation of flavonoids from sour Jujube seed. The flavonoids extract can reduce A-induced toxicity in Caenorhabditis elegans.

Cynthia R Davidson et al. (2002) East Coast Worm Meeting "Ray pattern and P3.p cell lineage evolution in Caenorhabditis."

Cynthia R Davidson, Scott E Baird, Justin C Bohrer

[East Coast Worm Meeting, 2002]

Ray pattern is one of the most variable morphological characters in rhabditid nematodes. C. elegans and C. remanei exhibit a 2(1)3+3 pattern in which ray 3 is separate from other rays and located at the anus. This pattern is ancestral in the 'elegans group' of Caenorhabditis (Sudhaus and Kiontke, 1996). A derived 2/4+3 ray pattern in which ray 3 is posterior of the anus and frequently fused with ray 4 is diagnostic for C. briggsae. However, this pattern is not fixed and three C. briggsae strains have been identified that exhibit both the derived and ancestral patterns (Baird, 2001). Using this variation, it should be possible to identify the genes responsible for ray pattern evolution in Caenorhabditis. Phenotypic segregation has demonstrated that ray pattern variation in C. briggsae results from allelic variation at two or three major-effect genes. Analyses of mutant phenotypes in C. elegans suggest that ray pattern evolution may result from alterations of HOM-C/Hox gene expression patterns (Chow and Emmons, 1994). Alterations in anteroposterior positional information also may account for evolutionary changes in the P3.p cell lineage. In C. briggsae, P3.p cell division frequency exhibits strain-specific variation (Dellatre and Flix, 2001). This variation correlates with ray pattern variation in C. briggsae males. To confirm this correlation, ray pattern and P3.p cell division frequency are being tested for cosegregation in crosses between variant strains. Single nucleotide polymorphisms (SNPs) from several C. briggsae strains are being identified at the Washington University Genome Sequencing Center. These SNPs will be used to map the genes responsible for ray pattern and P3.p cell division frequency variation. Initial experiments will focus on candidate genes known to regulate HOM-C/Hox gene expression patterns. If no linkage to candidates is detected, recombination mapping will proceed with SNPs distributed throughout the genome. Baird, S. E. (2001) Strain-specific variation in the pattern of caudal papillae in Caenorhabditis briggsae (Nematoda; Rhabditidae); implications for species identification. Nematology 3: 373-376.

Rie Matsui et al. (1999) International C. elegans Meeting "Regulation of the expression of mab-21: a candidate Hox target gene"

Naoki Takahashi, Rie Matsui, Daihachiro Tomotsune

[International C. elegans Meeting, 1999]

The Hox genes determine cell fates along the anterior-posterior body axis of many organisms. Hox gene products are believed to be transcription factors that regulate expression of target genes. We identified several candidate Hox gene targets by immunopurification of DNA sequences bound to a Hox protein in native chromatin (1). Recently, we isolated a mouse orthologue of C. elegans mab-21 as a candidate target of HoxC4. In C. elegans , mutations in mab-21 result in loss of the ray 6 morphology and fusion this ray with ray 4. This mutant phenotype is similar to that of the egl-5 ( Hox ). It is implicated that mab-21 acts in the same pathway as egl-5 in specification of ray morphology by genetic analysis (2). These results suggest that mab-21 gene is a candidate target of Hox gene products. The expression pattern of mab-21 has been studied using GFP reporter gene fusion. The last fifth exon of mab-21 was fused in frame with GFP (using Andy Fire vector pPD. 95.75) and 3.2Kb of 5' flanking sequence was included. mab-21::gfp expression is first seen in the hypodermal cells in pre-comma stage. In adult animals, mab-21::gfp is expressed in the hypodermal cells, neurons, head muscles and ray6. We identified the elements necessary and sufficient for mab-21 gene expression using deletion constructs. The deletion analysis indicated that a 450bp region upstream of the transcription start site is sufficient for hypodermal cell expression. A 300bp region in the fourth intron of the mab-21 is necessary for neuron expression and a 450bp region in the intron of the mab-21 is necessary for ray 6 expression. We are currently testing whether egl-5 can drive ectopic expression from a reporter construct containing ray 6 control element. (1). Tomotsune et al., (1993) Nature 365: 69-72 (2). Chow et al., (1994) Development 120: 2579-2593