Pharyngeal Pumping Assay v1

2022 ◽  
Author(s):  
Thomas J O'Brien
Keyword(s):  
Alimentary Tract ◽  
Feeding Rate ◽  
Complete Cycle ◽  
C Elegans ◽  
Precise Timing ◽  
Synchronous Contraction ◽  
Pharyngeal Pumping ◽  
Terminal Bulb ◽  
Contraction And Relaxation

The pharynx is a is a neuromuscular pump found at the anterior end of the alimentary tract, consisting of 20 muscles and 20 neurons. A proper feeding rate in worms is coordinated by the precise timing of pharyngeal movements, with one complete cycle of synchronous contraction and relaxation of the corpus and terminal bulb termed a “pump”. A simple way to measure C. elegans feeding is to count how many times worms pump in a minute (pumps per minute). Movement of the grinder (in the terminal bulb) can easily be observed using a stereomicroscope, and because cycles of contraction/relaxation are synchronised along the pharynx, pumps per minute can be measured simply by counting grinder movements.

scholarly journals C. elegans PEZO-1 is a Mechanosensitive Channel Involved in Food Sensation

2021 ◽  
Author(s):  
Jonathan R.M. Millet ◽  
Luis O Romero ◽  
Jungsoo Lee ◽  
Valeria Vásquez
Keyword(s):  
Fine Tuning ◽  
Mechanosensitive Channel ◽  
C Elegans ◽  
Physiological Processes ◽  
Embryo Cultures ◽  
Mechanosensitive Ion Channel ◽  
Food Content ◽  
Pharyngeal Pumping ◽  
Contraction And Relaxation ◽  
Pharyngeal Function

PIEZO channels are force sensors essential for physiological processes including baroreception and proprioception. The Caenorhabditis elegans genome encodes an ortholog gene of the Piezo family, pezo-1, expressed in several tissues including the pharynx. This myogenic pump is an essential component of the C. elegans alimentary canal whose contraction and relaxation are modulated by mechanical stimulation elicited by food content. Whether pezo-1 encodes a mechanosensitive channel and contributes to pharyngeal function remains unknown. Here, we leverage genome editing, genetics, microfluidics, and electropharyngeogram recordings to establish that pezo-1 is expressed in the pharynx, including a proprioceptive-like neuron, and regulates pharyngeal function. Knockout (KO) and gain-of-function (GOF) mutants reveal that pezo-1 is involved in fine-tuning pharyngeal pumping frequency, sensing osmolarity, and food quality. Using pressure-clamp experiments in primary C. elegans embryo cultures, we determine that pezo-1 KO cells do not display mechanosensitive currents, whereas cells expressing wild-type or GOF PEZO-1 exhibit mechanosensitivity. Moreover, infecting the Spodoptera frugiperda cell line with a baculovirus containing the pezo-1 isoform G (among the longest isoforms) demonstrates that pezo-1 encodes a mechanosensitive channel. Our findings reveal that pezo-1 is a mechanosensitive ion channel that regulates food sensation in worms.

scholarly journals Pharyngeal timing and particle transport defects in Caenorhabditis elegans feeding mutants

2021 ◽  
Author(s):  
Isaac Ravi Brenner ◽  
David M. Raizen ◽  
Christopher Fang-Yen
Keyword(s):  
Particle Transport ◽  
High Speed ◽  
Muscle Relaxation ◽  
Behavioral Deficits ◽  
Pumping Rate ◽  
C Elegans ◽  
Food Particles ◽  
Weak Muscle ◽  
Pharyngeal Pumping ◽  
Contraction And Relaxation

AbstractThe nematode C. elegans uses rhythmic muscle contractions and relaxations called pumps to filter, transport, and crush food particles. A number of feeding mutants have been identified, including those with slow pharyngeal pumping rate, weak muscle contraction, defective muscle relaxation, and defective grinding of bacteria. Many aspects of these pharyngeal behavioral defects and how they affect pharyngeal function are not well understood. For example, the behavioral deficits underlying inefficient particle transport in ‘slippery’ mutants have been unclear. Here we use high speed video microscopy to describe pharyngeal pumping behaviors and particle transport in wild-type animals and in feeding mutants. Different ‘slippery’ mutants exhibit distinct defects including weak isthmus contraction, failure to trap particles in the anterior isthmus, and abnormal timing of contraction and relaxation in pharyngeal compartments. Our results show that multiple deficits in pharyngeal timing or contraction can cause defects in particle transport.

scholarly journals Functional Characterization of the Adenylyl Cyclase Genesgs-1by Analysis of a Mutational Spectrum inCaenorhabditis elegans

Genetics ◽  
2002 ◽  
Vol 161 (1) ◽  
pp. 133-142 ◽  
Author(s):  
Celine Moorman ◽  
Ronald H A Plasterk
Keyword(s):  
Life Span ◽  
Adenylyl Cyclase ◽  
Neuronal Degeneration ◽  
Functional Characterization ◽  
Adenylyl Cyclases ◽  
Loss Of Function ◽  
C Elegans ◽  
Larval Stages ◽  
Pharyngeal Pumping

AbstractThe sgs-1 (suppressor of activated Gαs) gene encodes one of the four adenylyl cyclases in the nematode C. elegans and is most similar to mammalian adenylyl cyclase type IX. We isolated a complete loss-of-function mutation in sgs-1 and found it to result in animals with retarded development that arrest in variable larval stages. sgs-1 mutant animals exhibit lethargic movement and pharyngeal pumping and (while not reaching adulthood) have a mean life span that is >50% extended compared to wild type. An extensive set of reduction-of-function mutations in sgs-1 was isolated in a screen for suppressors of a neuronal degeneration phenotype induced by the expression of a constitutively active version of the heterotrimeric Gαs subunit of C. elegans. Although most of these mutations change conserved residues within the catalytic domains of sgs-1, mutations in the less-conserved transmembrane domains are also found. The sgs-1 reduction-of-function mutants are viable and have reduced locomotion rates, but do not show defects in pharyngeal pumping or life span.

Neuropeptide signalling shapes feeding and reproductive behaviours in male C. elegans

2021 ◽  
Author(s):  
Matthew J Gadenne ◽  
Iris Hardege ◽  
Djordji Suleski ◽  
Paris Jaggers ◽  
Isabel Beets ◽  
...  
Keyword(s):  
Synaptic Connectivity ◽  
Male Mating ◽  
Sexually Dimorphic ◽  
C Elegans ◽  
Mating Efficiency ◽  
Sexually Dimorphic Expression ◽  
Pharyngeal Pumping ◽  
Insight Into ◽  
Feeding Behaviours ◽  
Dimorphic Expression

Sexual dimorphism occurs where different sexes of the same species display differences in characteristics not limited to reproduction. For the nematode Caenorhabditis elegans, in which the complete neuroanatomy has been solved for both hermaphrodites and males, sexually dimorphic features have been observed both in terms of the number of neurons and in synaptic connectivity. In addition, male behaviours, such as food-leaving to prioritise searching for mates, have been attributed to neuropeptides released from sex-shared or sex-specific neurons. In this study, we show that the lury-1 neuropeptide gene shows a sexually dimorphic expression pattern; being expressed in pharyngeal neurons in both sexes but displaying additional expression in tail neurons only in the male. We also show that lury-1 mutant animals show sex differences in feeding behaviours, with pharyngeal pumping elevated in hermaphrodites but reduced in males. LURY-1 also modulates male mating efficiency, influencing motor events during contact with a hermaphrodite. Our findings indicate sex-specific roles of this peptide in feeding and reproduction in C. elegans, providing further insight into neuromodulatory control of sexually dimorphic behaviours.

scholarly journals Short-term hyperglycaemia induces motor defects in C. elegans

2017 ◽  
Author(s):  
Runita Shirdhankar ◽  
Nabila Sorathia ◽  
Medha Rajyadhyaksha
Keyword(s):  
Nervous System ◽  
Sensory Function ◽  
Motor Behaviour ◽  
Response Index ◽  
C Elegans ◽  
Cellular Effects ◽  
Pharyngeal Pumping ◽  
Intracellular Changes ◽  
Behaviour Study ◽  
Chemosensory Systems

AbstractHyperglycaemia causes various intracellular changes resulting in oxidative stress leading to loss of integrity and cell death. While cellular effects of hyperglycaemia have been reported extensively there is no clarity on whether the cellular changes translate into alterations in behaviour. Study of behavioural alterations also provides a sublime top-down approach to dapple the putative systems affected due to hyperglycaemic stress. Hence, this aspect of effect of hyperglycaemia deserves attention as it could be an early indicator of neurodegenerative changes. Caenorhabditis elegans is an excellent model to address these questions since it has a simple nervous system and the ability to respond to various cues.We have investigated alteration in behaviour which involves various motor and sensory function of the C. elegans nervous system under hyperglycaemia. Exposure of C. elegans to 400 mM glucose for 4hr did not kill the worm but gave rise to decreased number of progeny, exhibiting other aberrant behaviours. This dosage was considered to cause hyperglycaemic stress and used further in the studies. Various assays that quantified behaviour, such as feeding (pharyngeal pumping/min), locomotion (distance travelled by the worms/min), olfactory response towards Butanol (response index) and gustatory response NaCl (response index) were conducted under both normal and hyperglycaemic conditions. The behavioural alterations were validated by scrutinizing changes in level of Acetylchloine which regulates motor behaviour and morphology of chemosensory neurons. Our results indicate that hyperglycaemia alters motor behaviour of the worm which was validated by a reduction in ACh levels. However, chemosensory systems were robust enough to resist reduction in neuronal integrity due to hyperglycaemic assault.

scholarly journals A scalable method for automatically measuring pharyngeal pumping in C. elegans

2016 ◽  
Author(s):  
Monika Scholz ◽  
Dylan J. Lynch ◽  
Kyung Suk Lee ◽  
Erel Levine ◽  
David Biron
Keyword(s):  
Caenorhabditis Elegans ◽  
Food Availability ◽  
High Throughput ◽  
Visual Inspection ◽  
Automated Analysis ◽  
C Elegans ◽  
Automated Method ◽  
Controlled Environments ◽  
Pharyngeal Pumping ◽  
Feeding Environments

We describe a scalable automated method for measuring the pharyngeal pumping of Caenorhabditis elegans in controlled environments. Our approach enables unbiased measurements for prolonged periods, a high throughput, and measurements in controlled yet dynamically changing feeding environments. The automated analysis compares well with scoring pumping by visual inspection, a common practice in the field. In addition, we observed overall low rates of pharyngeal pumping and long correlation times when food availability was oscillated.

scholarly journals NemaLife: A structured microfluidic culture device optimized for aging studies in crawling C. elegans

2019 ◽  
Author(s):  
Mizanur Rahman ◽  
Hunter Edwards ◽  
Nikolajs Birze ◽  
Rebecca Gabrilska ◽  
Kendra P. Rumbaugh ◽  
...  
Keyword(s):  
Large Scale ◽  
The Body ◽  
Physiological Data ◽  
Aging Research ◽  
C Elegans ◽  
Age Related ◽  
Technology Platforms ◽  
Aging Studies ◽  
Pharyngeal Pumping ◽  
Culture Maintenance

AbstractCaenorhabditis elegans is a powerful animal model in aging research. Standard longevity assays on agar plates involve the tedious task of picking and transferring animals to prevent younger progeny from contaminating age-synchronized adult populations. Large-scale studies employ progeny-blocking drugs or sterile mutants to avoid progeny contamination, but such manipulations change adult physiology and alter the influence of reproduction on normal aging. Moreover, for some agar growth-based technology platforms, such as automated lifespan machines, reagents such as food or drugs cannot be readily added/removed after initiation of the study. Current microfluidic approaches are well-suited to address these limitations, but in their liquid-based environments animals swim rather than crawl, introducing swim-induced stress in the lifespan analysis. Here we report a simple microfluidic device that we call NemaLife that features: 1) an optimized micropillar arena in which animals can crawl, 2) sieve channels that separate progeny and prevent the loss of adults from the arena during culture maintenance, and 3) ports which allow rapid accessibility to feed the adult-only population and introduce reagents as needed. Culture maintenance and liquid manipulation are performed with simple hand-held syringes to facilitate integration of our technology into general laboratory protocols. Additionally, device geometry and feeding protocols were designed to emulate the body gait, locomotion, and lifespan of animals reared on agar. We validated our approach with longevity analyses of classical aging mutants (daf-2, age-1, eat-2, and daf-16) and animals subjected to RNAi knockdown of age-related genes (age-1 and daf-16). We also showed that healthspan measures such as pharyngeal pumping and tap-induced stimulated reversals can be scored across the lifespan. Overall, the capacity to generate reliable lifespan and physiological data from the NemaLife chip underscores the potential of this device to accelerate healthspan and lifespan investigations in C. elegans.

scholarly journals Pharyngeal Pumping Variability Assessment Reveals Subtle Mutant and Treatment Effects in the Nematode C. elegans

2020 ◽  
Vol 34 (S1) ◽  
pp. 1-1
Author(s):  
Michael B. Harris ◽  
Christopher Barrientos ◽  
Andy Bui ◽  
Mary Co ◽  
Sunny Gill ◽  
...  
Keyword(s):  
Treatment Effects ◽  
C Elegans ◽  
Pharyngeal Pumping

scholarly journals Cholinergic signalling at the body wall neuromuscular junction couples to distal inhibition of feeding in C. elegans

2021 ◽  
Author(s):  
Patricia G. Izquierdo ◽  
Thibana Thisainathan ◽  
James H. Atkins ◽  
Christian J. Lewis ◽  
John E.H. Tattersall ◽  
...  
Keyword(s):  
Body Wall ◽  
Neuromuscular Junctions ◽  
Model Organism ◽  
Inhibitory Effect ◽  
The Body ◽  
Body Wall Muscle ◽  
Cholinergic Transmission ◽  
Systematic Screening ◽  
C Elegans ◽  
Pharyngeal Pumping

AbstractComplex biological functions within organisms are frequently orchestrated by systemic communication between tissues. In the model organism C. elegans, the pharyngeal and body wall neuromuscular junctions are two discrete structures that control feeding and locomotion, respectively. These distinct tissues are controlled by separate, well-defined neural circuits. Nonetheless, the emergent behaviours, feeding and locomotion, are coordinated to guarantee the efficiency of food intake. We show that pharmacological hyperactivation of cholinergic transmission at the body wall muscle reduces the rate of pumping behaviour. This was evidenced by a systematic screening of the cholinesterase inhibitor aldicarb’s effect on the rate of pharyngeal pumping on food in mutant worms. The screening revealed that the key determinant of the inhibitory effect of aldicarb on pharyngeal pumping is the L-type nicotinic acetylcholine receptor expressed in body wall muscle. This idea was reinforced by the observation that selective hyperstimulation of the body wall muscle L-type receptor by the agonist levamisole inhibited pumping. Overall, our results reveal that body wall cholinergic transmission controls locomotion and simultaneously couples a distal inhibition of feeding.

scholarly journals Enhanced Healthspan in Caenorhabditis elegans Treated With Extracts From the Traditional Chinese Medicine Plants Cuscuta chinensis Lam. and Eucommia ulmoides Oliv.

2021 ◽  
Vol 12 ◽  
Author(s):  
Shimaa M. A. Sayed ◽  
Karsten Siems ◽  
Christian Schmitz-Linneweber ◽  
Walter Luyten ◽  
Nadine Saul
Keyword(s):  
Caenorhabditis Elegans ◽  
Chinese Medicine ◽  
Traditional Chinese Medicine ◽  
Eucommia Ulmoides ◽  
Pumping Rate ◽  
C Elegans ◽  
Beneficial Effects ◽  
Physiological Fitness ◽  
Pharyngeal Pumping ◽  
Cuscuta Chinensis

To uncover potential anti-aging capacities of Traditional Chinese Medicine (TCM), the nematode Caenorhabditis elegans was used to investigate the effects of Eucommia ulmoides and Cuscuta chinensis extracts, selected by screening seven TCM extracts, on different healthspan parameters. Nematodes exposed to E. ulmoides and C. chinensis extracts, starting at the young adult stage, exhibited prolonged lifespan and increased survival after heat stress as well as upon exposure to the pathogenic bacterium Photorhabdus luminescens, whereby the survival benefits were monitored after stress initiation at different adult stages. However, only C. chinensis had the ability to enhance physical fitness: the swimming behavior and the pharyngeal pumping rate of C. elegans were improved at day 7 and especially at day 12 of adulthood. Finally, monitoring the red fluorescence of aged worms revealed that only C. chinensis extracts caused suppression of intestinal autofluorescence, a known marker of aging. The results underline the different modes of action of the tested plants extracts. E. ulmoides improved specifically the physiological fitness by increasing the survival probability of C. elegans after stress, while C. chinensis seems to be an overall healthspan enhancer, reflected in the suppressed autofluorescence, with beneficial effects on physical as well as physiological fitness. The C. chinensis effects may be hormetic: this is supported by increased gene expression of hsp-16.1 and by trend, also of hsp-12.6.

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