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[
Worm Breeder's Gazette,
1994]
WHAT SNAKES AND WORMS HAVE IN COMMON: DISINTEGRINS Benjamin Podbilewicz, MRC Laboratory of Molecular Biology, Cambridge, UK
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Aging, Metabolism, Stress, Pathogenesis, and Small RNAs, Madison, WI,
2010]
Under ultraviolet light (lambda~340nm) worms show punctate blue fluorescence (lambda ~430nm), particularly in the gut. In worm cohorts, mean intensity of blue fluorescence increases with age, and is commonly used as a biomarker of worm aging1,2. It has been suggested that this fluorescent material is lipofuscin1, a heterogeneous aggregate of damaged macromolecules which in mammals accumulates with age within lysosomes, and which also shows blue fluorescence3. In worms, blue fluorescence occurs within lysosome-related organelles4 We have reassessed the parallels drawn between blue fluorescence and lipofuscin. Firstly, we monitored blue fluorescence throughout life in individual worms, rather than measuring average levels in population cohorts. We saw no increase in blue fluorescence during most of the worms' lifetimes, but instead a dramatic, rapid burst (mean ~5-fold increase, p=2.8e-13) of blue fluorescence just as the worms died. A similar fluorescent burst was also seen when young adults were killed, e.g. by heat, freeze-thaw or pH<3. Thus, a burst of blue fluorescence seems to be typical of organismal death in C. elegans, irrespective of cause. We also found that exposure to hyperoxia sufficient to increase protein oxidation did not increase blue fluorescence. To better characterize the dynamics of the blue fluorescent burst at the organismal level, we used stop motion photography. The striking, rapid spread of the blue fluorescence appears to mark the passage of death through the organism. The fluorescent burst starts with a focal increase in fluorescence, typically in the anterior gut. A wave of fluorescence then moves rapidly (3-4hrs) along the intestine. The blue fluorescence eventually penetrates all tissues except the gonad, and then fades from the corpse of the worm. The entire duration of the burst is around 20 hours. These results imply that blue fluorescence is a marker of organismal death rather than of aging, and suggest that the blue fluorescent material is something other than lipofuscin. The chemical identity of the fluorescent material remains a mystery, although one property it possesses is pH sensitivity: its blue fluorescence is enhanced by low pH. 1. Klass, Mech Ageing Dev 6, 413 (1977). 2. Gerstbrein et al., Aging Cell 4, 127. 3. Brunk & Terman, Free Radic Biol Med 33, 611 (2002). 4. Hermann et al., Mol Biol Cell 16, 3273 (2005).
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Curr Protoc Toxicol,
2016]
Response via noxious stimulus can be an important indicator of sensory neuron function and overall health of an organism. If the stimulation is quick and simple, and the animal can be rescued afterwards, such a method not only allows for assays pertaining to changed sensory ability after various treatments, but also increases the reliability of the statistical relationships that are established. This protocol demonstrates a stimulation assay in Caenorhabditis elegans, using blue light from common laboratory equipment: the fluorescent microscope. The nematode detects blue light using a set of amphid ciliary sensory neurons, and blue light is detrimental to its overall health after a prolonged exposure. However, under brief exposure, blue light stimulation provides a rapid and easy method for quantifying sensory functions and health without harming the animal. 2016 by John Wiley & Sons, Inc.
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International Worm Meeting,
2019]
For animals that do not provide parental care, when and where eggs are laid in the environment can have profound effects on the reproductive success of an individual. Because of its importance, it is not surprising that egg-laying is highly regulated in response to environmental cues. This regulation, coupled with the well described neural circuitry involved in the act of egg-laying, make it a great system for studying how animals interpret their environment and make behavioral choices. To facilitate this line of research we have developed a microfluidic "egg-counter" that allows 32 nematodes to reside in individual growth chambers while their egg-laying behavior is recorded at a sub-minute temporal resolution. The platform utilizes a perfusion-based feeding system that allows experimental control of the chemical environment as well as a built-in temperature control unit that allows the temperature to be patterned with 0.1 deg C accuracy without the use of incubators or temperature control rooms. Preliminary analysis of egg-laying behavior from wildtype animals in our microfluidic environment grossly fits that of the three-state model used to describe egg-laying on agar plates, with the log-tail distribution of egg-laying intervals exhibiting a bi-phasic distribution consistent with two interval types, inter and intra-cluster intervals. We will present a genetic characterization of the role of insulin signaling in regulating egg-laying behavior.
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[
Trop Med Parasitol,
1985]
A filarial species of unknown origin was frequently found in Simulium sanctipauli s.l. in the rain-forest zone of Liberia. After staining the cephalic armature with alcian blue its first stage larvae could be easily distinguished from those of Onchocerca volvulus.
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Curr Biol,
2024]
Stereotyped oscillations in population neural activity recordings from immobilized Caenorhabditis elegans have garnered interest for their striking low dimensionality and their evocative state-space trajectories or manifolds. Previously these oscillations have been interpreted as intrinsically driven global motor commands. Here we test whether these oscillations are intrinsic. We show that similar oscillations are evoked by high-intensity blue light commonly used for calcium imaging. Oscillations are reduced or absent and have a lower frequency when a longer imaging wavelength is used. Under the original blue light illumination, oscillations are reduced or have a lower frequency in animals that lack GUR-3, an endogenous light- and hydrogen-peroxide-sensitive gustatory receptor. Additional experiments with hydrogen peroxide are consistent with GUR-3's involvement. We therefore propose that blue light evokes global oscillations in part through the creation of reactive oxygen species that activate the hydrogen-peroxide-sensing receptor GUR-3.
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PLoS One,
2012]
The DNA/RNA-binding proteins TDP-43 and FUS are found in protein aggregates in a growing number of neurodegenerative diseases, including amyotrophic lateral sclerosis (ALS) and related dementia, but little is known about the neurotoxic mechanisms. We have generated Caenorhabditis elegans and zebrafish animal models expressing mutant human TDP-43 (A315T or G348C) or FUS (S57 or R521H) that reflect certain aspects of ALS including motor neuron degeneration, axonal deficits, and progressive paralysis. To explore the potential of our humanized transgenic C. elegans and zebrafish in identifying chemical suppressors of mutant TDP-43 and FUS neuronal toxicity, we tested three compounds with potential neuroprotective properties: lithium chloride, methylene blue and riluzole. We identified methylene blue as a potent suppressor of TDP-43 and FUS toxicity in both our models. Our results indicate that methylene blue can rescue toxic phenotypes associated with mutant TDP-43 and FUS including neuronal dysfunction and oxidative stress.
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International Worm Meeting,
2017]
Here we establish that contrary to expectations, Caenorhabditis elegans nematode worms possess a color discrimination system despite lacking any opsin or other photoreceptor genes. We found that simulated daylight guides C. elegans foraging decisions with respect to harmful bacteria that secrete a blue pigment toxin. By absorbing yellow-orange light, this blue pigment toxin alters the color of light sensed by the worm, and thereby triggers an increase in avoidance of harmful bacteria. These studies thus establish the existence of a color detection system that is distinct from those of other animals. In addition, these studies reveal an unexpected contribution of microbial color display to visual ecology.
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[
Worm Breeder's Gazette,
1976]
Unfertilized oocytes, 'squashy eggs', can be scored on a petri plate by adding a few drops of 0.05% Trypan blue to the surface of the plate. The oocytes take up the dye and worms and zygotes do not. The dye has no apparent effect on the worms left on the plate.
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J Environ Sci Health A Tox Hazard Subst Environ Eng,
2017]
This study aimed to investigate the biological impact of exposure on domestic light emitting diodes (LED) lighting using the free-living nematode Caenorhabditis elegans as a model. Nematodes were separately exposed to white LED light covering the range of 380-750nm, blue light at 450nm and black light at 380-420nm for one life cycle (egg to adult) with dark exposure as the control. Each light range induced stress to the nematode C. elegans such as reducing the number of the hatched eggs and/or delayed the maturation of the hatched eggs to the adult stage. In addition, it lowered or prevented the ability of adults to lay eggs and impaired the locomotion in the exposed worms. The observed type of biological stress was also associated with the production of reactive oxygen species (ROS) as compared to nematodes grown in the dark. It is concluded that the blue light component of white LED light may cause health problems, and further investigation is required to test commercial brands of white LEDs that emit different amounts of blue light.