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Updated: Sep 26, 2026
Using Single-Worm Data to Quantify Heterogeneity in Caenorhabditis elegans-Bacterial Interactions
Published on: July 22, 2022
Antibacterial properties of hemerythrin of the sand worm Nereis diversicolor
Laurence Deloffre1, Beatrice Salzet, Didier Vieau
1Laboratoire de Neuroimmunologie des Annélides, UMR CNRS 8017, IFR 118, SN3, Université des Sciences et Technologies de Lille, F-59655 Villeneuve D'Ascq cedex, FRANCE.
Objectives:
To investigate the immune defense of the annelid Nereis diversicolor and the key role of a oxygen-binding protein, the metalloprotein MPII animals were subjected to bacteria infection.
Methods And Results:
Using RACE-PCR, we have cloned the complete cDNA coding for the MPII related to the hemerythrin family in the sand worm Hediste diversicolor. This cDNA (883 pb) codes for a polypeptide of 119 amino acid residues with no signal peptide. Previous works have identified this protein as a cadmium scavenger. We here clearly demonstrated that this protein is also involved in the worm defence towards bacteria growth by its iron scavenger ability. This protein is expressed and produced in a haematopoietic center that floats freely in the coelomic fluid before stored in a particular hemocyte type: the granulocyte type 1. During bacterial challenge, this protein contained in these cells is discharged into the blood stream 3-4 hours after the infection and remains active for approximately 10 hours. This time period blocks progression of the pathogen and its attachment to tissues.
Conclusion:
These results reflect that MPII in conjunction with others partners like lysozyme act as defence molecule for the sand worm.
Insights
The metalloprotein MPII in the sand worm Hediste diversicolor acts as an iron scavenger, defending against bacterial infections. This immune protein is released into the bloodstream to block pathogen growth and attachment.
Area of Science:
- Marine biology
- Immunology
- Biochemistry
Background:
- Annelids possess innate immune systems for defense.
- Oxygen-binding proteins can have diverse biological functions.
Purpose of the Study:
- To investigate the immune defense role of metalloprotein MPII in Nereis diversicolor.
- To understand the function of MPII during bacterial infection.
Main Methods:
- Cloning of MPII cDNA using RACE-PCR.
- Analysis of protein structure and localization.
- Experimental bacterial challenge to observe MPII activity.
Main Results:
- MPII cDNA (883 bp) codes for a 119-amino acid polypeptide.
- MPII functions as an iron scavenger, aiding in defense against bacterial growth.
- MPII is stored in granulocytes and released into the coelomic fluid upon infection, inhibiting pathogens for ~10 hours.
Conclusions:
- MPII is a key immune defense molecule in Nereis diversicolor.
- MPII works alongside other molecules like lysozyme to protect the worm.
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