Pharyngeal timing and particle transport defects in Caenorhabditis elegans feeding mutants

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.

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

Frontiers in Pharmacology ◽

10.3389/fphar.2021.604435 ◽

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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Some Phenotypic Characteristics of Nematode Caenorhabditis elegans Strains with Defective Functions of the Sestrin (cSesn) gene

Biomedical & Pharmacology Journal ◽

10.13005/bpj/1430 ◽

2018 ◽

Vol 11 (2) ◽

pp. 759-767 ◽

Cited By ~ 3

Author(s):

A. O. Zeltukhin ◽

G. V. Ilyinskaya ◽

A. V. Budanov ◽

P. M. Chumakov

Keyword(s):

Caenorhabditis Elegans ◽

Redox Homeostasis ◽

Functional Decline ◽

Extended Period ◽

Locomotory Activity ◽

Pumping Rate ◽

Phenotypic Differences ◽

C Elegans ◽

Age Related ◽

Pharyngeal Pumping

In mammals a small family of genes called Sestrins play important roles in the maintenance of metabolic and redox homeostasis, suggesting that the genes may positively affect the lifespan and counteract the age-related functional decline. The nematode genome contains a single cSesn gene that makes the Caenorhabditis elegans an excellent model for studying functions of the sestrin family. We describe phenotypic differences of worms that have compromised expression of cSesn gene. By comparing three different cSesn-deficient modes with the wild-type C. elegans strain we show that the abrogation of cSesn expression results in an increased body size, an extended period of body growth, a reduces brood size and number of offspring per a single worm, an accelerated decline in muscular functions revealed as a rapid decrease in the pharyngeal pumping rate and in the overall locomotory activity. The results are consistent with the potential roles of cSesn in counteracting the process of aging in C. elegans.

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

10.1101/2021.05.10.443141 ◽

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.

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Pharyngeal Pumping Assay v1

10.17504/protocols.io.b3hiqj4e ◽

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.

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Gαq Mediates Clozapine Effects in Caenorhabditis elegans

10.1101/101998 ◽

2017 ◽

Author(s):

Limin Hao ◽

Yongguang Tong ◽

Kristin Harrington ◽

Jessica L. O’Neill ◽

Afsaneh Sheikholeslami ◽

...

Keyword(s):

Dopamine Receptors ◽

Genetic Model ◽

Behavioral Effects ◽

Type I ◽

Pumping Rate ◽

C Elegans ◽

Clozapine Treatment ◽

Downstream Effects ◽

Pharyngeal Pumping ◽

Second Messenger Signaling

ABSTRACTClozapine binds and has significant effects on multiple neurotransmitter receptors, notably including some dopamine receptors. Downstream of these receptors, clozapine affects the balance of Gi− and Gq-dependent second-messenger signaling. We used Caenorhabiditis elegans as a genetic model to study further how clozapine affects both dopamine receptors and downstream Gq mediated signaling. Four of six worm dopamine receptor orthologs, dop-1, dop-2, dop-4, and dop-5 produced resistance to clozapine induced developmental delay when mutated, suggesting that both type I and type II dopamine receptors mediate the behavioral effects of clozapine in C. elegans. Beyond these receptors, reduction of function of one of the G proteins, egl-30 (Gαq), produced greatly increased susceptibility to clozapine. Gαq has multiple known downstream effects. Among these is the control of acetylcholine release, which is in balance with monoamines in the human brain and is another target of clozapine and other antipsychotic drugs. We tested for downstream effects on acetylcholine at the neuromuscular junction upon clozapine treatment but found no evidence for effects of clozapine. In contrast, modulation of Gαq upstream leads to worms that are either more resistant or more susceptible to clozapine, emphasizing the importance of Gαq proteins in mediating effects of clozapine. A genetic screen for suppressors of egl-30 recovered eight mutants. By characterizing the behavioral effects of these mutants, we found that clozapine exerts its function on development by affecting Gαq signaling through control of the pharyngeal pumping rate. A whole-genome sequencing technique was utilized and identified a list of candidate genes for these suppressor mutations. Further characterization of these mutants promises the discovery of novel components participating in Gαq signaling and a better understanding of the mechanisms of action of clozapine.

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Catalpol Modulates Lifespan via DAF-16/FOXO and SKN-1/Nrf2 Activation inCaenorhabditis elegans

Evidence-based Complementary and Alternative Medicine ◽

10.1155/2015/524878 ◽

2015 ◽

Vol 2015 ◽

pp. 1-10 ◽

Cited By ~ 18

Author(s):

Hyun Won Seo ◽

Se Myung Cheon ◽

Myon-Hee Lee ◽

Hong Jun Kim ◽

Hoon Jeon ◽

...

Keyword(s):

Stress Tolerance ◽

Antioxidant Enzyme Activities ◽

Related Factors ◽

Pumping Rate ◽

Resistance Proteins ◽

C Elegans ◽

Normal Culture Condition ◽

Nrf2 Activation ◽

Pharyngeal Pumping ◽

Effective Component

Catalpol is an effective component of rehmannia root and known to possess various pharmacological properties. The present study was aimed at investigating the potential effects of catalpol on the lifespan and stress tolerance usingC. elegansmodel system. Herein, catalpol showed potent lifespan extension of wild-type nematode under normal culture condition. In addition, survival rate of catalpol-fed nematodes was significantly elevated compared to untreated control under heat and oxidative stress but not under hyperosmolality conditions. We also found that elevated antioxidant enzyme activities and expressions of stress resistance proteins were attributed to catalpol-mediated increased stress tolerance of nematode. We further investigated whether catalpol’s longevity effect is related to aging-related factors including reproduction, food intake, and growth. Interestingly, catalpol exposure could attenuate pharyngeal pumping rate, indicating that catalpol may induce dietary restriction of nematode. Moreover, locomotory ability of aged nematode was significantly improved by catalpol treatment, while lipofuscin levels were attenuated, suggesting that catalpol may affect age-associated changes of nematode. Our mechanistic studies revealed thatmek-1, daf-2, age-1, daf-16, andskn-1are involved in catalpol-mediated longevity. These results indicate that catalpol extends lifespan and increases stress tolerance ofC. elegansvia DAF-16/FOXO and SKN-1/Nrf activation dependent on insulin/IGF signaling and JNK signaling.

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

Genetics ◽

10.1093/genetics/161.1.133 ◽

2002 ◽

Vol 161 (1) ◽

pp. 133-142 ◽

Cited By ~ 4

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.

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

10.1101/2021.11.29.470485 ◽

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.

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Influence of Pipeline Inclination on Hydraulic Conveying of Sand Particles

Volume 7: Fluids and Heat Transfer, Parts A, B, C, and D ◽

10.1115/imece2012-93199 ◽

2012 ◽

Cited By ~ 1

Author(s):

Ahmed Mohamed Nossair ◽

Peter Rodgers ◽

Afshin Goharzadeh

Keyword(s):

Particle Transport ◽

High Speed ◽

Sand Dune ◽

Sand Particle ◽

Hydrocarbon Production ◽

Production Wells ◽

Load Transport ◽

Bed Load Transport ◽

Sand Particles ◽

Dune Dynamics

The understanding of sand particle transport by fluids in pipelines is of importance for the drilling of horizontal and inclined hydrocarbon production wells, topside process facilities, infield pipelines, and trunk lines. Previous studies on hydraulic conveying of sand particles in pipelines have made significant contributions to the understanding of multiphase flow patterns, pressure drop and particle transport rate in horizontal pipelines. However, due to the complexity of the flow structure resulting from liquid-sand interactions, the mechanisms responsible for bed-load transport flow for hydraulic conveying of sand particles have not been extensively studied in inclined pipelines. This paper presents an experimental investigation of hydraulic conveying of sand particles resulting from a stationary flat bed in both horizontal and +3.6 degree upward inclined pipelines. The characteristics of sand transportation by saltation from an initial sand bed are experimentally visualized using a transparent Plexiglas pipeline and high-speed digital photography. The dune formation process is assessed as a function of pipeline orientation. Based on the visualized dune morphology, pipeline inclination is found to have a significant influence on hydraulic conveying of sand dune dynamics (i.e., dune velocity), as well as sand dune geometry (i.e., dune pitch and characteristic dune angles).

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The Influence of water flow rate on Pumping Rate in Mytilus Edulis using a Refined Direct Measurement Apparatus

Journal of the Marine Biological Association of the United Kingdom ◽

10.1017/s0025315400018932 ◽

1976 ◽

Vol 56 (2) ◽

pp. 311-319 ◽

Cited By ~ 23

Author(s):

D. I. Hildreth

Keyword(s):

Water Flow ◽

Direct Measurement ◽

Water Flow Rate ◽

Mantle Cavity ◽

Water Current ◽

Ciliary Activity ◽

Pumping Rate ◽

Influence Of Water ◽

Food Particles ◽

Flow Through

INTRODUCTIONWork on pumping and filtration rates of bivalve molluscs was initially concerned with the physiological concept of pumping water through the mantle cavity. Comprehensive reviews are given by Winter (1970) and Ali (1971). The methods are of two kinds; direct, in which the flow of exhaled water itself is measured, and indirect, in which the rate of clearance of food particles is used to calculate water flow through the gills.There is a disadvantage in the indirect method when used to calculate volumes of water pumped because it involves the assumption that a fixed percentage (often 100% with large particles) of the particulate matter passing through the gill system is retained. Pumping rate is thus estimated as a function of the particle collecting properties of the latero-frontal cirri, whereas the water current is produced by the lateral cilia. Although the structure of the latero-frontal cirri is now well documented (Moore, 1971), their efficiency in particle retention can alter under certain conditions (Dral, 1967). There is need, therefore, for direct measurement of the quantity of water pumped. Recent advances in the understanding of branchial innervation and the control of lateral ciliary activity also reinforce this point (Aiello, 1960, 1962, 1970; Paparo, 1972, 1973).The constant level chamber for direct measurement of pumping rate was devised by Galtsoff (1926), to ensure that separation of the exhalant water current from the bivalve was not interfered with by pressure differences produced by the process of separation. The apparatus has been used in various forms by Galtsoff (1926, 1928, 1946), Nelson (1935, 1936), Collier & Ray (1948), Loosanoff & Engle (1947), Loosanoff & Nomejko (1946) and more recently by Drinnan (1964) and Davids (1964).

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