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Updated: Aug 7, 2025
Isolation and Characterization of the Natural Microbiota of the Model Nematode Caenorhabditis elegans
Published on: August 17, 2022
Isolation and molecular identification of nematode surface mutants with resistance to bacterial pathogens
Delia O'Rourke1, Maria J Gravato-Nobre1, Dave Stroud1
1Department of Biochemistry, University of Oxford, Oxford OX1 3QU, UK.
Abstract:
Numerous mutants of the nematode Caenorhabditis elegans with surface abnormalities have been isolated by utilizing their resistance to a variety of bacterial pathogens (Microbacterium nematophilum, Yersinia pseudotuberculosis, and 2 Leucobacter strains), all of which are able to cause disease or death when worms are grown on bacterial lawns containing these pathogens. Previous work led to the identification of 9 srf or bus genes; here, we report molecular identification and characterization of a further 10 surface-affecting genes. Three of these were found to encode factors implicated in glycosylation (srf-2, bus-5, and bus-22), like several of those previously reported; srf-2 belongs to the GT92 family of putative galactosyltransferases, and bus-5 is homologous to human dTDP-D-glucose 4,6-dehydratase, which is implicated in Catel-Manzke syndrome. Other genes encoded proteins with sequence similarity to phosphatidylinositol phosphatases (bus-6), Patched-related receptors (ptr-15/bus-13), steroid dehydrogenases (dhs-5/bus-21), or glypiation factors (bus-24). Three genes appeared to be nematode-specific (srf-5, bus-10, and bus-28). Many mutants exhibited cuticle fragility as revealed by bleach and detergent sensitivity; this fragility was correlated with increased drug sensitivity, as well as with abnormal skiddy locomotion. Most of the genes examined were found to be expressed in epidermal seam cells, which appear to be important for synthesizing nematode surface coat. The results reveal the genetic and biochemical complexity of this critical surface layer, and provide new tools for its analysis.
Insights
Researchers identified 10 new genes affecting the nematode surface coat, revealing its complex genetic makeup. Many mutants showed cuticle fragility and altered locomotion, highlighting the importance of these genes for nematode health.
Area of Science:
- Molecular biology and genetics of nematode surface structures.
- Biochemistry of glycosylation and cell surface synthesis.
- Comparative genomics and evolutionary biology of surface coat genes.
Background:
- The nematode surface coat is crucial for protection against pathogens and environmental stress.
- Previous studies identified 9 genes (srf or bus) involved in surface coat formation.
- Understanding the genetic basis of surface coat integrity is vital for nematode biology.
Purpose of the Study:
- To identify and characterize novel genes involved in nematode surface coat formation.
- To elucidate the biochemical functions of newly identified surface-affecting genes.
- To investigate the relationship between surface coat integrity, pathogen resistance, and locomotion.
Main Methods:
- Isolation of nematode mutants resistant to bacterial pathogens.
- Molecular identification and characterization of 10 new surface-affecting genes.
- Analysis of gene function through homology to known protein families (glycosyltransferases, phosphatases, etc.).
- Assessment of cuticle integrity using bleach and detergent sensitivity assays.
- Gene expression analysis in epidermal seam cells.
Main Results:
- Ten novel surface-affecting genes (srf-2, bus-5, bus-22, bus-6, ptr-15/bus-13, dhs-5/bus-21, bus-24, srf-5, bus-10, bus-28) were identified and characterized.
- Three genes are implicated in glycosylation, including a putative galactosyltransferase (srf-2) and a homolog of human dTDP-D-glucose 4,6-dehydratase (bus-5).
- Mutants exhibited cuticle fragility, increased drug sensitivity, and abnormal locomotion, correlating with defects in surface coat synthesis.
- Most identified genes are expressed in epidermal seam cells, highlighting their role in surface coat production.
Conclusions:
- The study reveals the significant genetic and biochemical complexity of the nematode surface coat.
- Newly identified genes provide essential tools for further analysis of surface coat structure and function.
- Defects in surface coat genes have profound impacts on nematode physiology, including pathogen resistance and motility.
