The invertebrate Caenorhabditis elegans biosynthesizes ascorbate.

Area of Science:

• Biochemistry
• Molecular Biology
• Zoology

Background:

• l-Ascorbate (vitamin C) is a vital antioxidant and cofactor.
• Known biosynthetic pathways exist in animals and plants, but not invertebrates.
• Its role in C. elegans is hypothesized for oxidative stress and synthesis.

Purpose of the Study:

• Investigate ascorbate metabolism and synthesis in the nematode C. elegans.
• Determine if C. elegans possesses known animal or plant vitamin C pathways.
• Identify the source of ascorbate in C. elegans.

Main Methods:

• Quantified ascorbate levels using HPLC and GC-MS.
• Tested effects of precursor molecules on ascorbate levels.
• Performed bioinformatic analysis for biosynthetic genes.
• Utilized 13C-labeled E. coli to trace ascorbate synthesis.

Main Results:

• Ascorbate detected at low levels in C. elegans (eggs, larvae, mixed populations), highest in eggs.
• Precursor incubation did not increase ascorbate levels.
• No evidence for known animal or plant biosynthetic pathways found.
• Complete 13C-labeling of ascorbate observed when fed 13C-labeled E. coli.

Conclusions:

• C. elegans contains ascorbate but lacks known biosynthetic pathways.
• Evidence supports a novel, potentially diet-derived, ascorbate synthesis pathway in invertebrates.
• This research provides a foundation for understanding invertebrate vitamin C biology.