scholarly journals Caenorhabditis elegans PIEZO channel coordinates multiple reproductive tissues to govern ovulation

eLife ◽  
2020 ◽  
Vol 9 ◽  
Author(s):  
Xiaofei Bai ◽  
Jeff Bouffard ◽  
Avery Lord ◽  
Katherine Brugman ◽  
Paul W Sternberg ◽  
...  

PIEZO1 and PIEZO2 are newly identified mechanosensitive ion channels that exhibit a preference for calcium in response to mechanical stimuli. In this study, we discovered the vital roles of pezo-1, the sole PIEZO ortholog in Caenorhabditiselegans, in regulating reproduction. A number of deletion alleles, as well as a putative gain-of-function mutant, of PEZO-1 caused a severe reduction in brood size. In vivo observations showed that oocytes undergo a variety of transit defects as they enter and exit the spermatheca during ovulation. Post-ovulation oocytes were frequently damaged during spermathecal contraction. However, the calcium signaling was not dramatically changed in the pezo-1 mutants during ovulation. Loss of PEZO-1 also led to an inability of self-sperm to navigate back to the spermatheca properly after being pushed out of the spermatheca during ovulation. These findings suggest that PEZO-1 acts in different reproductive tissues to promote proper ovulation and fertilization in C. elegans.

2019 ◽  
Author(s):  
Xiaofei Bai ◽  
Jeff Bouffard ◽  
Avery Lord ◽  
Katherine Brugman ◽  
Paul W. Sternberg ◽  
...  

AbstractThe PIEZO proteins are involved in a wide range of developmental and physiological processes. Human PIEZO1 and PIEZO2 are newly identified excitatory mechano-sensitive proteins; they are non-selective ion channels that exhibit a preference for calcium in response to mechanical stimuli. To further understand the function of these proteins, we investigated the roles of pezo-1, the sole PIEZO ortholog in C. elegans. pezo-1 is expressed throughout development in C. elegans, with strong expression in reproductive tissues. A number of deletion alleles as well as a putative gain-of-function mutant caused severe defects in reproduction. A reduced brood size was observed in the strains depleted of PEZO-1. In vivo observations show that oocytes undergo a variety of transit defects as they enter and exit the spermatheca during ovulation. Post ovulation oocytes were frequently damaged during spermathecal contraction. Calcium signaling in the spermatheca is normal during ovulation in pezo-1 mutants, however, pezo-1 interacts genetically with known regulators of calcium signaling. Lastly, loss of PEZO-1 caused defective sperm navigation after being pushed out of the spermatheca during ovulation. Mating with males rescued these reproductive deficiencies in our pezo-1 mutants. These findings suggest that PEZO-1 may act in different reproductive tissues to promote proper ovulation and fertilization in C. elegans.


1996 ◽  
Vol 133 (5) ◽  
pp. 1071-1081 ◽  
Author(s):  
C C Lai ◽  
K Hong ◽  
M Kinnell ◽  
M Chalfie ◽  
M Driscoll

The process by which mechanical stimuli are converted into cellular responses is poorly understood, in part because key molecules in this mode of signal transduction, the mechanically gated ion channels, have eluded cloning efforts. The Caenorhabditis elegans mec-4 gene encodes a subunit of a candidate mechanosensitive ion channel that plays a critical role in touch reception. Comparative sequence analysis of C. elegans and Caenorhabditis briggsae mec-4 genes was used to initiate molecular studies that establish MEC-4 as a 768-amino acid protein that includes two hydrophobic domains theoretically capable of spanning a lipid bilayer. Immunoprecipitation of in vitro translated mec-4 protein with domain-specific anti-MEC-4 antibodies and in vivo characterization of a series of mec-4lacZ fusion proteins both support the hypothesis that MEC-4 crosses the membrane twice. The MEC-4 amino- and carboxy-terminal domains are situated in the cytoplasm and a large domain, which includes three Cys-rich regions, is extracellular. Definition of transmembrane topology defines regions that might interact with the extracellular matrix or cytoskeleton to mediate mechanical signaling.


2021 ◽  
pp. 1-9
Author(s):  
Dayana Torres Valladares ◽  
Sirisha Kudumala ◽  
Murad Hossain ◽  
Lucia Carvelli

Amphetamine is a potent psychostimulant also used to treat attention deficit/hyperactivity disorder and narcolepsy. In vivo and in vitro data have demonstrated that amphetamine increases the amount of extra synaptic dopamine by both inhibiting reuptake and promoting efflux of dopamine through the dopamine transporter. Previous studies have shown that chronic use of amphetamine causes tolerance to the drug. Thus, since the molecular mechanisms underlying tolerance to amphetamine are still unknown, an animal model to identify the neurochemical mechanisms associated with drug tolerance is greatly needed. Here we took advantage of a unique behavior caused by amphetamine in <i>Caenorhabditis elegans</i> to investigate whether this simple, but powerful, genetic model develops tolerance following repeated exposure to amphetamine. We found that at least 3 treatments with 0.5 mM amphetamine were necessary to see a reduction in the amphetamine-induced behavior and, thus, to promote tolerance. Moreover, we found that, after intervals of 60/90 minutes between treatments, animals were more likely to exhibit tolerance than animals that underwent 10-minute intervals between treatments. Taken together, our results show that <i>C. elegans</i> is a suitable system to study tolerance to drugs of abuse such as amphetamines.


Development ◽  
1992 ◽  
Vol 114 (2) ◽  
pp. 317-330 ◽  
Author(s):  
O. Bossinger ◽  
E. Schierenberg

The pattern of autofluorescence in the two free-living namatodes Rhabditis dolichura and Caenorhabditis compared. In C. elegans, during later embryogenesis cells develop a typical bluish autofluorescence as illumination, while in Rh. dolichura a strong already present in the unfertilized egg. Using a new,


Nutrients ◽  
2018 ◽  
Vol 10 (12) ◽  
pp. 2002 ◽  
Author(s):  
Cristina Moliner ◽  
Lillian Barros ◽  
Maria Dias ◽  
Víctor López ◽  
Elisa Langa ◽  
...  

Tagetes erecta L. has long been consumed for culinary and medicinal purposes in different countries. The aim of this study was to explore the potential benefits from two cultivars of T. erecta related to its polyphenolic profile as well as antioxidant and anti-aging properties. The phenolic composition was analyzed by LC-DAD-ESI/MSn. Folin-Ciocalteu, DPPH·, and FRAP assays were performed in order to evaluate reducing antiradical properties. The neuroprotective potential was evaluated using the enzymes acetylcholinesterase and monoamine oxidase. Caenorhabditis elegans was used as an in vivo model to assess extract toxicity, antioxidant activity, delayed aging, and reduced β-amyloid toxicity. Both extracts showed similar phenolic profiles and bioactivities. The main polyphenols found were laricitin and its glycosides. No acute toxicity was detected for extracts in the C. elegans model. T. erecta flower extracts showed promising antioxidant and neuroprotective properties in the different tested models. Hence, these results may add some information supporting the possibilities of using these plants as functional foods and/or as nutraceutical ingredients.


2019 ◽  
Author(s):  
S. Katta ◽  
A. Sanzeni ◽  
A. Das ◽  
M. Vergassola ◽  
M.B. Goodman

AbstractTouch deforms, or strains, the skin beyond the immediate point of contact. The spatiotemporal nature of the touch-induced strain fields depend on the mechanical properties of the skin and the tissues below. Somatosensory neurons that sense touch branch out within the skin and rely on a set of mechano-electrical transduction channels distributed within their dendrites to detect mechanical stimuli. Here, we sought to understand how tissue mechanics shape touch-induced mechanical strain across the skin over time and how individual channels located in different regions of the strain field contribute to the overall touch response. We leveraged C. elegans’ touch receptor neurons (TRNs) as a simple model amenable to in vivo whole-cell patch clamp recording and an integrated experimental-computational approach to dissect the mechanisms underlying the spatial and temporal dynamics that we observed. Consistent with the idea that strain is produced at a distance, we show that delivering strong stimuli outside the anatomical extent of the neuron is sufficient to evoke MRCs. The amplitude and kinetics of the MRCs depended on both stimulus displacement and speed. Finally, we found that the main factor responsible for touch sensitivity is the recruitment of progressively more distant channels by stronger stimuli, rather than modulation of channel open probability. This principle may generalize to somatosensory neurons with more complex morphologies.SummaryThrough experiment and simulation, Katta et al. reveal that pushing faster and deeper recruits more and more distant mechano-electrical transduction channels during touch. The net result is a dynamic receptive field whose size and shape depends on tissue mechanics, stimulus parameters, and channel distribution within sensory neurons.


Genetics ◽  
1994 ◽  
Vol 136 (1) ◽  
pp. 145-154
Author(s):  
I Katsura ◽  
K Kondo ◽  
T Amano ◽  
T Ishihara ◽  
M Kawakami

Abstract We have isolated 13 fluoride-resistant mutants of the nematode Caenorhabditis elegans. All the mutations are recessive and mapped to five genes. Mutants in three of the genes (class 1 genes: flr-1 X, flr-3 IV, and flr-4 X) are resistant to 400 micrograms/ml NaF. Furthermore, they grow twice as slowly as and have smaller brood size than wild-type worms even in the absence of fluoride ion. In contrast, mutants in the other two genes (class 2 genes: flr-2 V and flr-5 V) are only partially resistant to 400 micrograms/ml NaF, and they have almost normal growth rates and brood sizes in the absence of fluoride ion. Studies on the phenotypes of double mutants showed that class 2 mutations are epistatic to class 1 mutations concerning growth rate and brood size but hypostatic with respect to fluoride resistance. We propose two models that can explain the epistasis. Since fluoride ion depletes calcium ion, inhibits some protein phosphatases and activates trimeric G-proteins, studies on these mutants may lead to discovery of a new signal transduction system that controls the growth of C. elegans.


2005 ◽  
Vol 73 (11) ◽  
pp. 7236-7242 ◽  
Author(s):  
Creg Darby ◽  
Sandya L. Ananth ◽  
Li Tan ◽  
B. Joseph Hinnebusch

ABSTRACT Yersinia pestis, the cause of bubonic plague, blocks feeding by its vector, the flea. Recent evidence indicates that blockage is mediated by an in vivo biofilm. Y. pestis and the closely related Yersinia pseudotuberculosis also make biofilms on the cuticle of the nematode Caenorhabditis elegans, which block this laboratory animal's feeding. Random screening of Y. pseudotuberculosis transposon insertion mutants with a C. elegans biofilm assay identified gmhA as a gene required for normal biofilms. gmhA encodes phosphoheptose isomerase, an enzyme required for synthesis of heptose, a conserved component of lipopolysaccharide and lipooligosaccharide. A Y. pestis gmhA mutant was constructed and was severely defective for C. elegans biofilm formation and for flea blockage but only moderately defective in an in vitro biofilm assay. These results validate use of the C. elegans biofilm system to identify genes and pathways involved in Y. pestis flea blockage.


Author(s):  
Vikram Joshi ◽  
Peter R Strege ◽  
Gianrico Farrugia ◽  
Arthur Beyder

Mechanosensation, the ability to properly sense mechanical stimuli and transduce them into physiologic responses, is an essential determinant of gastrointestinal (GI) function. Abnormalities in this process result in highly prevalent GI functional and motility disorders. In the GI tract, several cell types sense mechanical forces and transduce them into electrical signals, which elicit specific cellular responses. Some mechanosensitive cells like sensory neurons act as specialized mechanosensitive cells that detect forces and transduce signals into tissue-level physiologic reactions. Non-specialized mechanosensitive cells like smooth muscle cells (SMCs) adjust their function in response to forces. Mechanosensitive cells utilize various mechanoreceptors and mechanotransducers. Mechanoreceptors detect and convert force into electrical and biochemical signals, and mechanotransducers amplify and direct mechanoreceptor responses. Mechanoreceptors and mechanotransducers include ion channels, specialized cytoskeletal proteins, cell junction molecules, and G-protein coupled receptors. SMCs are particularly important due to their role as final effectors for motor function. Myogenic reflex-the ability of smooth muscle to contract in response to stretch rapidly-is a critical smooth muscle function. Such rapid mechanotransduction responses rely on mechano-gated and -sensitive ion channels, which alter their ion pores' opening in response to force, allowing fast electrical and Ca2+ responses. Though GI SMCs express a variety of such ion channels, their identities remain unknown. Recent advancements in electrophysiological, genetic, in vivo imaging, and multi-omic technologies broaden our understanding of how SMC mechano-gated and -sensitive ion channels regulate GI functions. This review discusses GI SMC mechanosensitivity's current developments with a particular emphasis on mechano-gated and -sensitive ion channels.


Antioxidants ◽  
2020 ◽  
Vol 9 (9) ◽  
pp. 811
Author(s):  
Cristina Moliner ◽  
Víctor López ◽  
Lillian Barros ◽  
Maria Inês Dias ◽  
Isabel C. F. R. Ferreira ◽  
...  

Rosmarinus officinalis L., commonly known as rosemary, has been largely studied for its wide use as food ingredient and medicinal plant; less attention has been given to its edible flowers, being necessary to evaluate their potential as functional foods or nutraceuticals. To achieve that, the phenolic profile of the ethanolic extract of R. officinalis flowers was determined using LC-DAD-ESI/MSn and then its antioxidant and anti-ageing potential was studied through in vitro and in vivo assays using Caenorhabditis elegans. The phenolic content was 14.3 ± 0.1 mg/g extract, trans rosmarinic acid being the predominant compound in the extract, which also exhibited a strong antioxidant capacity in vitro and increased the survival rate of C. elegans exposed to lethal oxidative stress. Moreover, R. officinalis flowers extended C. elegans lifespan up to 18%. Therefore, these findings support the potential use of R. officinalis flowers as ingredients to develop products with pharmaceutical and/or nutraceutical potential.


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