scholarly journals The early embryonic development of the satellite organism Pristionchus pacificus: differences and similarities with Caenorhabditis elegans

Nematology ◽  
2008 ◽  
Vol 10 (3) ◽  
pp. 301-312 ◽  
Author(s):  
Gaetan Borgonie ◽  
Wim Bert ◽  
Wouter Houthoofd ◽  
Sandra Vangestel
Keyword(s):  
Caenorhabditis Elegans ◽  
Embryonic Development ◽  
Early Development ◽  
Model Organism ◽  
Embryonic Cell ◽  
Early Embryonic Development ◽  
Cell Contacts ◽  
Pristionchus Pacificus ◽  
C Elegans ◽  
Cell Cell

AbstractAs a comparative counterpart for the model organism Caenorhabditis elegans, the nematode Pristionchus pacificus was established as a satellite organism to study developmental processes. However, these studies mainly focused on post-embryonic development and little is known about the early embryonic development. Using 4D microscopy we reconstructed the early embryonic cell lineage of 12 individuals of P. pacificus. By analysing several parameters of early development, including the division sequence, the spatial arrangement of blastomeres, the cell cycle patterns of the AB lineage and cell-cell contacts in different cell stages of the embryo, it was shown that the early embryonic development is nearly identical to C. elegans. Known cell-cell contacts necessary for induction of blastomere fates in C. elegans are also present in P. pacificus. Thus, the spatio-temporal conditions that would allow possible homologous inductions are present. However, at least one model for blastomere specification seems not to apply to P. pacificus since the third division in the AB lineage differs from that of C. elegans. Furthermore, naturally occurring variability of early development was demonstrated, which is clearly permitted since there seems to be no influence on further development into an adult worm.

scholarly journals Student Learning of Early Embryonic Development via the Utilization of Research Resources from the Nematode Caenorhabditis elegans

2008 ◽  
Vol 7 (1) ◽  
pp. 64-73 ◽  
Author(s):  
Fong-Mei Lu ◽  
Kevin W. Eliceiri ◽  
Jayne M. Squirrell ◽  
John G. White ◽  
James Stewart
Keyword(s):  
Caenorhabditis Elegans ◽  
Embryonic Development ◽  
Student Learning ◽  
Undergraduate Students ◽  
Biological Significance ◽  
Embryonic Cell ◽  
Instructional Materials ◽  
Early Embryonic Development ◽  
Inquiry Based Learning ◽  
Research Resources

This study was undertaken to gain insights into undergraduate students' understanding of early embryonic development, specifically, how well they comprehend the concepts of volume constancy, cell lineages, body plan axes, and temporal and spatial dimensionality in development. To study student learning, a curriculum was developed incorporating resources from the Caenorhabditis elegans research community. Students engaged in a preactivity assessment, followed by instructional materials (IMs) emphasizing inquiry-based learning and a postinstruction assessment to gauge their learning. This study, conducted at two research sites with eight and nine students, respectively, shows that before instruction, most students confused embryonic cell cleavage, where total volume is constant, with regular cell division, in which total cell volume doubles. Despite their ability to construct a cell lineage tree, most of the study participants were not aware of its biological significance. All students correctly identified cells of anterior and posterior axis, but not cells of the dorsal and ventral axis. Although the students had no difficulty with the time dimensional aspect of development, most viewed an embryo as spatially two-dimensional rather than three-dimensional. Furthermore, this study indicates that combining authentic research resources with inquiry-based learning benefits student learning of key concepts in embryology.

scholarly journals Identification of novel chondroitin proteoglycans in Caenorhabditis elegans: embryonic cell division depends on CPG-1 and CPG-2

2006 ◽  
Vol 173 (6) ◽  
pp. 985-994 ◽  
Author(s):  
Sara K. Olson ◽  
Joseph R. Bishop ◽  
John R. Yates ◽  
Karen Oegema ◽  
Jeffrey D. Esko
Keyword(s):  
Caenorhabditis Elegans ◽  
Embryonic Development ◽  
Embryonic Cell ◽  
Tissue Mechanics ◽  
Nematode Caenorhabditis Elegans ◽  
Biochemical Purification ◽  
Hydra Vulgaris ◽  
C Elegans ◽  
Core Proteins ◽  
Embryonic Viability

Vertebrates produce multiple chondroitin sulfate proteoglycans that play important roles in development and tissue mechanics. In the nematode Caenorhabditis elegans, the chondroitin chains lack sulfate but nevertheless play essential roles in embryonic development and vulval morphogenesis. However, assignment of these functions to specific proteoglycans has been limited by the lack of identified core proteins. We used a combination of biochemical purification, Western blotting, and mass spectrometry to identify nine C. elegans chondroitin proteoglycan core proteins, none of which have homologues in vertebrates or other invertebrates such as Drosophila melanogaster or Hydra vulgaris. CPG-1/CEJ-1 and CPG-2 are expressed during embryonic development and bind chitin, suggesting a structural role in the egg. RNA interference (RNAi) depletion of individual CPGs had no effect on embryonic viability, but simultaneous depletion of CPG-1/CEJ-1 and CPG-2 resulted in multinucleated single-cell embryos. This embryonic lethality phenocopies RNAi depletion of the SQV-5 chondroitin synthase, suggesting that chondroitin chains on these two proteoglycans are required for cytokinesis.

Behavioral Effects of Volatile Anesthetics in Caenorhabditis elegans

1996 ◽  
Vol 85 (4) ◽  
pp. 901-912 ◽  
Author(s):  
Michael C. Crowder ◽  
Laynie D. Shebester ◽  
Tim Schedl
Keyword(s):  
Nervous System ◽  
Caenorhabditis Elegans ◽  
Time Course ◽  
Model Organism ◽  
Volatile Anesthetic ◽  
Volatile Anesthetics ◽  
Effective Concentration ◽  
Forward Genetics ◽  
C Elegans ◽  
Median Effective Concentration

Background The nematode Caenorhabditis elegans offers many advantages as a model organism for studying volatile anesthetic actions. It has a simple, well-understood nervous system; it allows the researcher to do forward genetics; and its genome will soon be completely sequenced. C. elegans is immobilized by volatile anesthetics only at high concentrations and with an unusually slow time course. Here other behavioral dysfunctions are considered as anesthetic endpoints in C. elegans. Methods The potency of halothane for disrupting eight different behaviors was determined by logistic regression of concentration and response data. Other volatile anesthetics were also tested for some behaviors. Established protocols were used for behavioral endpoints that, except for pharyngeal pumping, were set as complete disruption of the behavior. Time courses were measured for rapid behaviors. Recovery from exposure to 1 or 4 vol% halothane was determined for mating, chemotaxis, and gross movement. All experiments were performed at 20 to 22 degrees C. Results The median effective concentration values for halothane inhibition of mating (0.30 vol%-0.21 mM), chemotaxis (0.34 vol%-0.24 mM), and coordinated movement (0.32 vol% - 0.23 mM) were similar to the human minimum alveolar concentration (MAC; 0.21 mM). In contrast, halothane produced immobility with a median effective concentration of 3.65 vol% (2.6 mM). Other behaviors had intermediate sensitivities. Halothane's effects reached steady-state in 10 min for all behaviors tested except immobility, which required 2 h. Recovery was complete after exposure to 1 vol% halothane but was significantly reduced after exposure to immobilizing concentrations. Conclusions Volatile anesthetics selectively disrupt C. elegans behavior. The potency, time course, and recovery characteristics of halothane's effects on three behaviors are similar to its anesthetic properties in vertebrates. The affected nervous system molecules may express structural motifs similar to those on vertebrate anesthetic targets.

scholarly journals Stochastic left–right neuronal asymmetry in Caenorhabditis elegans

2016 ◽  
Vol 371 (1710) ◽  
pp. 20150407 ◽  
Author(s):  
Amel Alqadah ◽  
Yi-Wen Hsieh ◽  
Rui Xiong ◽  
Chiou-Fen Chuang
Keyword(s):  
Caenorhabditis Elegans ◽  
Molecular Mechanisms ◽  
Neurological Diseases ◽  
Calcium Signalling ◽  
Model Organism ◽  
Brain Asymmetry ◽  
C Elegans ◽  
Left And Right ◽  
Left Right Asymmetry ◽  
Neuronal Asymmetry

Left–right asymmetry in the nervous system is observed across species. Defects in left–right cerebral asymmetry are linked to several neurological diseases, but the molecular mechanisms underlying brain asymmetry in vertebrates are still not very well understood. The Caenorhabditis elegans left and right amphid wing ‘C’ (AWC) olfactory neurons communicate through intercellular calcium signalling in a transient embryonic gap junction neural network to specify two asymmetric subtypes, AWC OFF (default) and AWC ON (induced), in a stochastic manner. Here, we highlight the molecular mechanisms that establish and maintain stochastic AWC asymmetry. As the components of the AWC asymmetry pathway are highly conserved, insights from the model organism C. elegans may provide a window onto how brain asymmetry develops in humans. This article is part of the themed issue ‘Provocative questions in left–right asymmetry’.

scholarly journals An Evolutionarily Conserved Pathway Essential for Orsay Virus Infection of Caenorhabditis elegans

mBio ◽  
2017 ◽  
Vol 8 (5) ◽  
Author(s):  
Hongbing Jiang ◽  
Kevin Chen ◽  
Luis E. Sandoval ◽  
Christian Leung ◽  
David Wang
Keyword(s):  
Caenorhabditis Elegans ◽  
Virus Infection ◽  
Tyrosine Kinase ◽  
Model Organism ◽  
Wiskott Aldrich Syndrome ◽  
C Elegans ◽  
Evolutionarily Conserved ◽  
Conserved Genes ◽  
Orsay Virus ◽  
Syndrome Protein

ABSTRACT Many fundamental biological discoveries have been made in Caenorhabditis elegans. The discovery of Orsay virus has enabled studies of host-virus interactions in this model organism. To identify host factors critical for Orsay virus infection, we designed a forward genetic screen that utilizes a virally induced green fluorescent protein (GFP) reporter. Following chemical mutagenesis, two Viro (virus induced reporter off) mutants that failed to express GFP were mapped to sid-3, a nonreceptor tyrosine kinase, and B0280.13 (renamed viro-2), an ortholog of human Wiskott-Aldrich syndrome protein (WASP). Both mutants yielded Orsay virus RNA levels comparable to that of the residual input virus, suggesting that they are not permissive for Orsay virus replication. In addition, we demonstrated that both genes affect an early prereplication stage of Orsay virus infection. Furthermore, it is known that the human ortholog of SID-3, activated CDC42-associated kinase (ACK1/TNK2), is capable of phosphorylating human WASP, suggesting that VIRO-2 may be a substrate for SID-3 in C. elegans. A targeted RNA interference (RNAi) knockdown screen further identified the C. elegans gene nck-1, which has a human ortholog that interacts with TNK2 and WASP, as required for Orsay virus infection. Thus, genetic screening in C. elegans identified critical roles in virus infection for evolutionarily conserved genes in a known human pathway. IMPORTANCE Orsay virus is the only known virus capable of naturally infecting the model organism Caenorhabditis elegans, which shares many evolutionarily conserved genes with humans. We exploited the robust genetic tractability of C. elegans to identify three host genes, sid-3, viro-2, and nck-1, which are essential for Orsay virus infection. Mutant animals that lack these three genes are highly defective in viral replication. Strikingly, the human orthologs of these three genes, activated CDC42-associated kinase (TNK2), Wiskott-Aldrich syndrome protein (WASP), and noncatalytic region of tyrosine kinase adaptor protein 1 (NCK1) are part of a known signaling pathway in mammals. These results suggest that TNK2, WASP, and NCK1 may play important roles in mammalian virus infection. IMPORTANCE Orsay virus is the only known virus capable of naturally infecting the model organism Caenorhabditis elegans, which shares many evolutionarily conserved genes with humans. We exploited the robust genetic tractability of C. elegans to identify three host genes, sid-3, viro-2, and nck-1, which are essential for Orsay virus infection. Mutant animals that lack these three genes are highly defective in viral replication. Strikingly, the human orthologs of these three genes, activated CDC42-associated kinase (TNK2), Wiskott-Aldrich syndrome protein (WASP), and noncatalytic region of tyrosine kinase adaptor protein 1 (NCK1) are part of a known signaling pathway in mammals. These results suggest that TNK2, WASP, and NCK1 may play important roles in mammalian virus infection.

PES-1 is expressed during early embryogenesis in Caenorhabditis elegans and has homology to the fork head family of transcription factors

Development ◽  
1994 ◽  
Vol 120 (3) ◽  
pp. 505-514 ◽  
Author(s):  
I.A. Hope
Keyword(s):  
Transcription Factors ◽  
Caenorhabditis Elegans ◽  
Cell Lineage ◽  
Embryonic Cell ◽  
Early Embryogenesis ◽  
C Elegans ◽  
Promoter Trapping ◽  
Fork Head ◽  
Initiation Of Transcription ◽  
Beta Galactosidase

Promoter trapping has identified a gene, pes-1, which is expressed during C. elegans embryogenesis. The beta-galactosidase expression pattern, directed by the pes-1/lacZ fusion through which this gene was cloned, has been determined precisely in terms of the embryonic cell lineage and has three components. One component is in a subset of cells of the AB founder cell lineage during early embryogenesis, suggesting pes-1 may be regulated both by cell autonomous determinants and by intercellular signals. Analysis of cDNA suggests pes-1 has two sites for initiation of transcription and the two transcripts would encode related but distinct proteins. The predicted PES-1 proteins have homology to the fork head family of transcription factors and therefore may have important regulatory roles in early embryogenesis.

Memoirs: The Early Embryonic Development of Rhodnius Prolixus (Hemiptera, Heteroptera)

1935 ◽  
Vol s2-78 (309) ◽  
pp. 71-90
Author(s):  
HELEN MELLANBY
Keyword(s):  
Relative Humidity ◽  
Embryonic Development ◽  
Early Development ◽  
Constant Temperature ◽  
Germ Cells ◽  
Rhodnius Prolixus ◽  
Posterior Pole ◽  
Early Embryonic Development ◽  
Temperature And Humidity ◽  
Cent Relative Humidity

1. Eggs of Rhodnius prolixus were incubated at constant temperature and humidity (21° C. and 90 per cent, relative humidity). Eighty-five per cent, was the lowest record of the controls hatched successfully under these conditions. 2. The processes of maturation and fertilization were not studied. 3. Cleavage begins 12-13 hours after incubation. At 25 hours there are 32 nuclei. Yolk-cells are derived from cleavage nuclei, and they multiply by mitosis up to 50 hours. Blastoderm formation is complete after 55-60 hours of incubation. 4. The ventral embryonic rudiment is similar to that of many other insects. As soon as it is formed, germ-cells are budded off at the posterior pole of the egg. 5. The first stage in blastokinesis is fully described. 6. The formation of the mesoderm is by invagination and overgrowth. 7. The endoderm arises from two proliferating areas situated anteriorly and posteriorly. 8. Numerous cells are given off into the yolk during the early development of the embryo. There they disintegrate.

scholarly journals Neuroligin dependence of social behaviour in Caenorhabditis elegans provides a model to investigate an autism-associated gene

2020 ◽  
Author(s):  
Helena Rawsthorne ◽  
Fernando Calahorro ◽  
Emily Feist ◽  
Lindy Holden-Dye ◽  
Vincent O’Connor ◽  
...  
Keyword(s):  
Caenorhabditis Elegans ◽  
Genetic Variants ◽  
Social Behaviour ◽  
Animal Studies ◽  
Model Organism ◽  
Autism Spectrum ◽  
C Elegans ◽  
Important Regulator ◽  
Human Mutation ◽  
The Impact

Abstract Autism spectrum disorder (ASD) is characterized by a triad of behavioural impairments including social behaviour. Neuroligin, a trans-synaptic adhesion molecule, has emerged as a penetrant genetic determinant of behavioural traits that signature the neuroatypical behaviours of autism. However, the function of neuroligin in social circuitry and the impact of genetic variation to this gene is not fully understood. Indeed, in animal studies designed to model autism, there remains controversy regarding the role of neuroligin dysfunction in the expression of disrupted social behaviours. The model organism, Caenorhabditis elegans, offers an informative experimental platform to investigate the impact of genetic variants on social behaviour. In a number of paradigms, it has been shown that inter-organismal communication by chemical cues regulates C. elegans social behaviour. We utilize this social behaviour to investigate the effect of autism-associated genetic variants within the social domain of the research domain criteria. We have identified neuroligin as an important regulator of social behaviour and segregate the importance of this gene to the recognition and/or processing of social cues. We also use CRISPR/Cas9 to edit an R-C mutation that mimics a highly penetrant human mutation associated with autism. C. elegans carrying this mutation phenocopy the behavioural dysfunction of a C. elegans neuroligin null mutant, thus confirming its significance in the regulation of animal social biology. This highlights that quantitative behaviour and precision genetic intervention can be used to manipulate discrete social circuits of the worm to provide further insight into complex social behaviour.

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