scholarly journals Studying Human Disease Genes in Caenorhabditis elegans: A Molecular Genetics Laboratory Project

2012 ◽  
Vol 11 (2) ◽  
pp. 165-179 ◽  
Author(s):  
Elisabeth A. Cox-Paulson ◽  
Theresa M. Grana ◽  
Michelle A. Harris ◽  
Janet M. Batzli
Keyword(s):  
Caenorhabditis Elegans ◽  
Molecular Genetics ◽  
Human Disease ◽  
Homozygous Deletion ◽  
Model System ◽  
Model Organisms ◽  
Disease Genes ◽  
Nested Polymerase Chain Reaction ◽  
C Elegans ◽  
Genetic Deletion

Scientists routinely integrate information from various channels to explore topics under study. We designed a 4-wk undergraduate laboratory module that used a multifaceted approach to study a question in molecular genetics. Specifically, students investigated whether Caenorhabditis elegans can be a useful model system for studying genes associated with human disease. In a large-enrollment, sophomore-level laboratory course, groups of three to four students were assigned a gene associated with either breast cancer (brc-1), Wilson disease (cua-1), ovarian dysgenesis (fshr-1), or colon cancer (mlh-1). Students compared observable phenotypes of wild-type C. elegans and C. elegans with a homozygous deletion in the assigned gene. They confirmed the genetic deletion with nested polymerase chain reaction and performed a bioinformatics analysis to predict how the deletion would affect the encoded mRNA and protein. Students also performed RNA interference (RNAi) against their assigned gene and evaluated whether RNAi caused a phenotype similar to that of the genetic deletion. As a capstone activity, students prepared scientific posters in which they presented their data, evaluated whether C. elegans was a useful model system for studying their assigned genes, and proposed future directions. Assessment showed gains in understanding genotype versus phenotype, RNAi, common bioinformatics tools, and the utility of model organisms.

The glycomes of Caenorhabditis elegans and other model organisms

2002 ◽  
Vol 69 ◽  
pp. 117-134 ◽  
Author(s):  
Stuart M. Haslam ◽  
David Gems ◽  
Howard R. Morris ◽  
Anne Dell
Keyword(s):  
Caenorhabditis Elegans ◽  
Current Knowledge ◽  
Structural Data ◽  
Model Organisms ◽  
Entire Genome ◽  
C Elegans ◽  
The Face ◽  
Area Of Concern ◽  
Nematode Worm

There is no doubt that the immense amount of information that is being generated by the initial sequencing and secondary interrogation of various genomes will change the face of glycobiological research. However, a major area of concern is that detailed structural knowledge of the ultimate products of genes that are identified as being involved in glycoconjugate biosynthesis is still limited. This is illustrated clearly by the nematode worm Caenorhabditis elegans, which was the first multicellular organism to have its entire genome sequenced. To date, only limited structural data on the glycosylated molecules of this organism have been reported. Our laboratory is addressing this problem by performing detailed MS structural characterization of the N-linked glycans of C. elegans; high-mannose structures dominate, with only minor amounts of complex-type structures. Novel, highly fucosylated truncated structures are also present which are difucosylated on the proximal N-acetylglucosamine of the chitobiose core as well as containing unusual Fucα1–2Gal1–2Man as peripheral structures. The implications of these results in terms of the identification of ligands for genomically predicted lectins and potential glycosyltransferases are discussed in this chapter. Current knowledge on the glycomes of other model organisms such as Dictyostelium discoideum, Saccharomyces cerevisiae and Drosophila melanogaster is also discussed briefly.

scholarly journals Caenorhabditis elegans as a Model System To Assess Candida glabrata, Candida nivariensis, and Candida bracarensis Virulence and Antifungal Efficacy

2020 ◽  
Vol 64 (10) ◽  
Author(s):  
Ainara Hernando-Ortiz ◽  
Estibaliz Mateo ◽  
Marcelo Ortega-Riveros ◽  
Iker De-la-Pinta ◽  
Guillermo Quindós ◽  
...  
Keyword(s):  
Caenorhabditis Elegans ◽  
Candida Glabrata ◽  
Model System ◽  
Antifungal Drugs ◽  
Phenotypic Traits ◽  
Content Type ◽  
C Elegans ◽  
Host Fungus ◽  
Candida Bracarensis ◽  
Candida Nivariensis

ABSTRACT Although Candida albicans remains the major etiological agent of invasive candidiasis, Candida glabrata and other emerging species of Candida are increasingly isolated. This species is the second most prevalent cause of candidiasis in many regions of the world. However, clinical isolates of Candida nivariensis and Candida bracarensis can be misidentified and are underdiagnosed due to phenotypic traits shared with C. glabrata. Little is known about the two cryptic species. Therefore, pathogenesis studies are needed to understand their virulence traits and their susceptibility to antifungal drugs. The susceptibility of Caenorhabditis elegans to different Candida species makes this nematode an excellent model for assessing host-fungus interactions. We evaluated the usefulness of C. elegans as a nonconventional host model to analyze the virulence of C. glabrata, C. nivariensis, and C. bracarensis. The three species caused candidiasis, and the highest virulence of C. glabrata was confirmed. Furthermore, we determined the efficacy of current antifungal drugs against the infection caused by these species in the C. elegans model. Amphotericin B and azoles showed the highest activity against C. glabrata and C. bracarensis infections, while echinocandins were more active for treating those caused by C. nivariensis. C. elegans proved to be a useful model system for assessing the pathogenicity of these closely related species.

scholarly journals Electrophysiological Measures of Aging Pharynx Function in C. elegans Reveal Enhanced Organ Functionality in Older, Long-lived Mutants

2017 ◽  
Vol 74 (8) ◽  
pp. 1173-1179 ◽  
Author(s):  
Joshua Coulter Russell ◽  
Nikolay Burnaevskiy ◽  
Bridget Ma ◽  
Miguel Arenas Mailig ◽  
Franklin Faust ◽  
...  
Keyword(s):  
Caenorhabditis Elegans ◽  
Heat Shock ◽  
Life Span ◽  
Insulin Signaling ◽  
Model System ◽  
Wild Type ◽  
Organ Function ◽  
C Elegans ◽  
Age Related ◽  
The Relationship

Abstract The function of the pharynx, an organ in the model system Caenorhabditis elegans, has been correlated with life span and motility (another measure of health) since 1980. In this study, in order to further understand the relationship between organ function and life span, we measured the age-related decline of the pharynx using an electrophysiological approach. We measured and analyzed electropharyngeograms (EPG) of wild type animals, short-lived hsf-1 mutants, and long-lived animals with genetically decreased insulin signaling or increased heat shock pathway signaling; we recorded a total of 2,478 EPGs from 1,374 individuals. As expected, the long-lived daf-2(e1370) and hsf-1OE(uthIs235) animals maintained pharynx function relatively closer to the youthful state during aging, whereas the hsf-1(sy441) and wild type animals’ pharynx function deviated significantly further from the youthful state at advanced age. Measures of the amount of variation in organ function can act as biomarkers of youthful physiology as well. Intriguingly, the long-lived animals had greater variation in the duration of pharynx contraction at older ages.

scholarly journals Rapid self-selecting and clone-free integration of transgenes into engineered CRISPR safe harbor locations in Caenorhabditis elegans

2020 ◽  
Author(s):  
Zachary C. Stevenson ◽  
Megan J. Moerdyk-Schauwecker ◽  
Brennen Jamison ◽  
Patrick C. Phillips
Keyword(s):  
Caenorhabditis Elegans ◽  
Single Copy ◽  
False Positives ◽  
Model Organisms ◽  
Screening Methods ◽  
Safe Harbor ◽  
Guide Rna ◽  
C Elegans ◽  
Pcr Products ◽  
Transgenic Lines

AbstractPrecision genome editing for model organisms has revolutionized functional analysis and validation of a wide variety of molecular systems. To date, the capacity to insert transgenes into the model nematode Caenorhabditis elegans has focused on utilizing either transposable elements or CRISPR-based safe harbor strategies. These methods require laborious screening processes that often result in false positives from heritable extrachromosomal arrays or rely on co-CRISPR markers to identify likely edited individuals. As a result, verification of transgene insertion requires anti-array selection screening methods or extensive PCR genotyping respectively. These approaches also rely on cloning plasmids for the addition of transgenes. Here, we present a novel safe harbor CRISPR-based integration strategy that utilizes engineered insertion locations containing a synthetic guide RNA target and a split-selection system to eliminate false positives from array formation, thereby providing integration-specific selection. This approach allows the experimenter to confirm an integration event has taken place without molecular validation or anti-array screening methods, and is capable of producing integrated transgenic lines in as little as five days post-injection. To further increase the speed of generating transgenic lines, we also utilized the C. elegans native homology-based formation of extra-chromosomal arrays to assemble transgenes in-situ, removing the cloning step. We show that complete transgenes can be made and inserted into our split-selection safe harbor locations starting from PCR products, providing a clone-free and molecular-validation-free strategy for single-copy transgene integration. Overall, this combination of approaches provides an economical and rapid system for generating highly reproducible complex transgenics in C. elegans.

scholarly journals The FDA-approved drugs ticlopidine, sertaconazole, and dexlansoprazole can cause morphological changes in C. elegans

2020 ◽  
Author(s):  
Kyle F Galford ◽  
Antony M Jose
Keyword(s):  
Proton Pump Inhibitor ◽  
Genetic Model ◽  
Morphological Changes ◽  
Model System ◽  
Model Organisms ◽  
Regulatory Agencies ◽  
C Elegans ◽  
Therapeutic Drugs ◽  
Approved Drugs ◽  
Fda Approved Drugs

AbstractUrgent need for treatments limit studies of therapeutic drugs before approval by regulatory agencies. Analyses of drugs after approval can therefore improve our understanding of their mechanism of action and enable better therapies. We screened a library of 1443 Food and Drug Administration (FDA)-approved drugs using a simple assay in the nematode C. elegans and found three compounds that caused morphological changes. While the anticoagulant ticlopidine and the antifungal sertaconazole caused morphologically distinct pharyngeal defects upon acute exposure, the proton-pump inhibitor dexlansoprazole caused molting defects and required exposure during larval development. Such easily detectable defects in a powerful genetic model system advocate the continued exploration of current medicines using a variety of model organisms to better understand drugs already prescribed to millions of patients.

scholarly journals Review of Biological Effects of Acute and Chronic Radiation Exposure on Caenorhabditis elegans

Cells ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 1966
Author(s):  
Rabin Dhakal ◽  
Mohammad Yosofvand ◽  
Mahsa Yavari ◽  
Ramzi Abdulrahman ◽  
Ryan Schurr ◽  
...  
Keyword(s):  
Caenorhabditis Elegans ◽  
Ionizing Radiation ◽  
Biological Effects ◽  
Model Organism ◽  
Model Organisms ◽  
C Elegans ◽  
Chronic Radiation ◽  
Biological Responses ◽  
Chronic Radiation Exposure ◽  
Acute And Chronic Exposure

Knowledge regarding complex radiation responses in biological systems can be enhanced using genetically amenable model organisms. In this manuscript, we reviewed the use of the nematode, Caenorhabditis elegans (C. elegans), as a model organism to investigate radiation’s biological effects. Diverse types of experiments were conducted on C. elegans, using acute and chronic exposure to different ionizing radiation types, and to assess various biological responses. These responses differed based on the type and dose of radiation and the chemical substances in which the worms were grown or maintained. A few studies compared responses to various radiation types and doses as well as other environmental exposures. Therefore, this paper focused on the effect of irradiation on C. elegans, based on the intensity of the radiation dose and the length of exposure and ways to decrease the effects of ionizing radiation. Moreover, we discussed several studies showing that dietary components such as vitamin A, polyunsaturated fatty acids, and polyphenol-rich food source may promote the resistance of C. elegans to ionizing radiation and increase their life span after irradiation.

scholarly journals Chlorophyll enhances oxidative stress tolerance inCaenorhabditis elegansand extends its lifespan

PeerJ ◽  
2016 ◽  
Vol 4 ◽  
pp. e1879 ◽  
Author(s):  
Erjia Wang ◽  
Michael Wink
Keyword(s):  
Oxidative Stress ◽  
Caenorhabditis Elegans ◽  
Secondary Metabolites ◽  
Model System ◽  
The Body ◽  
Aging Effects ◽  
Oxidative Stress Tolerance ◽  
C Elegans ◽  
Dependent Pathway

Green vegetables are thought to be responsible for several beneficial properties such as antioxidant, anti-mutagenic, and detoxification activities. It is not known whether these effects are due to chlorophyll which exists in large amounts in many foods or result from other secondary metabolites. In this study, we used the model systemCaenorhabditis elegansto investigate the anti-oxidative and anti-aging effects of chlorophyllin vivo. We found that chlorophyll significantly improves resistance to oxidative stress. It also enhances the lifespan ofC. elegansby up to 25% via activation of the DAF-16/FOXO-dependent pathway. The results indicate that chlorophyll is absorbed by the worms and is thus bioavailable, constituting an important prerequisite for antioxidant and longevity-promoting activities inside the body. Our study thereby supports the view that green vegetables may also be beneficial for humans.

scholarly journals An economical and highly adaptable optogenetics system for individual and population-level manipulation of Caenorhabditis elegans

BMC Biology ◽  
2021 ◽  
Vol 19 (1) ◽  
Author(s):  
M. Koopman ◽  
L. Janssen ◽  
E. A. A. Nollen
Keyword(s):  
Caenorhabditis Elegans ◽  
Light Stimulus ◽  
Cholinergic Neurons ◽  
Model Organisms ◽  
Parameter Study ◽  
Multiple Model ◽  
Excitable Cells ◽  
Specific Expression ◽  
C Elegans ◽  
Age Related

Abstract Background Optogenetics allows the experimental manipulation of excitable cells by a light stimulus without the need for technically challenging and invasive procedures. The high degree of spatial, temporal, and intensity control that can be achieved with a light stimulus, combined with cell type-specific expression of light-sensitive ion channels, enables highly specific and precise stimulation of excitable cells. Optogenetic tools have therefore revolutionized the study of neuronal circuits in a number of models, including Caenorhabditis elegans. Despite the existence of several optogenetic systems that allow spatial and temporal photoactivation of light-sensitive actuators in C. elegans, their high costs and low flexibility have limited wide access to optogenetics. Here, we developed an inexpensive, easy-to-build, modular, and adjustable optogenetics device for use on different microscopes and worm trackers, which we called the OptoArm. Results The OptoArm allows for single- and multiple-worm illumination and is adaptable in terms of light intensity, lighting profiles, and light color. We demonstrate OptoArm’s power in a population-based multi-parameter study on the contributions of motor circuit cells to age-related motility decline. We found that individual components of the neuromuscular system display different rates of age-dependent deterioration. The functional decline of cholinergic neurons mirrors motor decline, while GABAergic neurons and muscle cells are relatively age-resilient, suggesting that rate-limiting cells exist and determine neuronal circuit ageing. Conclusion We have assembled an economical, reliable, and highly adaptable optogenetics system which can be deployed to address diverse biological questions. We provide a detailed description of the construction as well as technical and biological validation of our set-up. Importantly, use of the OptoArm is not limited to C. elegans and may benefit studies in multiple model organisms, making optogenetics more accessible to the broader research community.

Genetics of Behavior in C. elegans

2017 ◽  
pp. 150-170 ◽  
Author(s):  
Denise S. Walker ◽  
Yee Lian Chew ◽  
William R. Schafer
Keyword(s):  
Nervous System ◽  
Caenorhabditis Elegans ◽  
Molecular Genetics ◽  
Sensory Information ◽  
Macro Level ◽  
Gene Products ◽  
Individual Gene ◽  
C Elegans ◽  
Behavioral States ◽  
Motor Outputs

The nematode Caenorhabditis elegans is among the most intensely studied animals in modern experimental biology. In particular, because of its amenability to classical and molecular genetics, its simple and compact nervous system, and its transparency to optogenetic recording and manipulation, C. elegans has been widely used to investigate how individual gene products act in the context of neuronal circuits to generate behavior. C. elegans is the first and at present the only animal whose neuronal connectome has been characterized at the level of individual neurons and synapses, and the wiring of this connectome shows surprising parallels with the micro- and macro-level structures of larger brains. This chapter reviews our current molecular- and circuit-level understanding of behavior in C. elegans. In particular, we discuss mechanisms underlying the processing of sensory information, the generation of specific motor outputs, and the control of behavioral states.

scholarly journals Rapid Self-Selecting and Clone-Free Integration of Transgenes into Engineered CRISPR Safe Harbor Locations in Caenorhabditis elegans

2020 ◽  
Vol 10 (10) ◽  
pp. 3775-3782
Author(s):  
Zachary C. Stevenson ◽  
Megan J. Moerdyk-Schauwecker ◽  
Brennen Jamison ◽  
Patrick C. Phillips
Keyword(s):  
Caenorhabditis Elegans ◽  
Single Copy ◽  
Model Organisms ◽  
Screening Methods ◽  
Safe Harbor ◽  
Molecular Systems ◽  
Guide Rna ◽  
C Elegans ◽  
Pcr Products ◽  
Transgenic Lines

Precision genome editing for model organisms has revolutionized functional analysis and validation of a wide variety of molecular systems. To date, the capacity to insert single-copy transgenes into the model nematode Caenorhabditis elegans has focused on utilizing either transposable elements or CRISPR-based safe harbor strategies. These methods require plate-level screening processes to avoid selecting heritable extrachromosomal arrays or rely on co-CRISPR markers to identify knock-in events. As a result, verification of transgene insertion requires anti-array selection screening methods and PCR genotyping. These approaches also rely on cloning plasmids for the addition of transgenes. Here, we present a novel safe harbor CRISPR-based integration strategy that utilizes engineered insertion locations containing a synthetic guide RNA target and a split-selection system to eliminate false positives from array formation, thereby providing integration-specific selection. This approach allows the experimenter to confirm an integration event has taken place without molecular validation or anti-array screening methods and is capable of producing integrated transgenic lines in as little as five days post-injection. To further increase the speed of generating transgenic lines, we also utilized the C. elegans native microhomology-based recombination, to assemble transgenes in-situ, removing the cloning step. We show that complete transgenes can be made and inserted into our split-selection safe harbor locations starting from PCR products, providing a clone-free and molecular-validation-free strategy for single-copy transgene integration. Overall, this combination of approaches provides an economical and rapid system for generating highly reproducible complex transgenics in C. elegans.

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