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Updated: Aug 18, 2026
Enrichment of Native and Recombinant Extracellular Vesicles of Mycobacteria
Published on: December 8, 2023
A novel plasmid (pEMCJH03) isolated from moraxella catarrhalis possibly useful as a cloning and expression vector
John P Hays1, Kimberly Eadie, Cees M Verduin
1Department of Medical Microbiology and Infectious Diseases, Erasmus MC (Erasmus University Medical Center), Dr. Molewaterplein 40, 3015 GD Rotterdam, The Netherlands. j.hays@erasmusmc.nl
Abstract:
A preliminary screening study of six Moraxella catarrhalis isolates from primary school children in the Netherlands identified a small 3.5 kb plasmid (pEMCJH03), containing four open reading frames, which encoded three mobilizing and one replicase protein. Insertion of a kanamycin containing transposon (yielding pEMCJH04) allowed selection and isolation of the plasmid in Escherichia coli. Natural transformation of pEMCJH04 into M. catarrhalis was successful for 25% (3/12) of non-isogenic isolates, with no link between (lack of) transformability and genetic lineage or (lack of) transformability and complement phenotype, though the transformation efficiency was found to be rather low at approximately 615CFU/microg (range=60-1040CFU/microg ). This is only the second publication detailing a plasmid isolated from this important respiratory pathogen, and the ability to clone and express foreign proteins in M. catarrhalis using pEMCJH04 could help in the development of a vaccine expression vector, as well as providing a useful tool for studying promoter activity and in complementation studies of gene knockout mutants.
Insights
Researchers isolated a novel plasmid, pEMCJH04, from Moraxella catarrhalis, a key respiratory pathogen. This plasmid can be transformed into M. catarrhalis, offering potential for vaccine development and genetic studies.
Area of Science:
- Microbiology
- Molecular Biology
- Genetics
Background:
- Moraxella catarrhalis is a significant respiratory pathogen.
- Plasmids are important genetic elements in bacteria, influencing virulence and adaptation.
- Limited information exists regarding plasmids in M. catarrhalis.
Purpose of the Study:
- To identify and characterize plasmids from Moraxella catarrhalis isolates.
- To assess the transformability of a novel plasmid in M. catarrhalis.
- To explore the potential applications of the isolated plasmid in molecular studies and vaccine development.
Main Methods:
- Screening of M. catarrhalis isolates for plasmids.
- Plasmid isolation and characterization using molecular techniques.
- Insertion of a transposon for selection and cloning in Escherichia coli.
- Natural transformation experiments in M. catarrhalis.
- Analysis of transformability in relation to genetic lineage and complement phenotype.
Main Results:
- A 3.5 kb plasmid, pEMCJH03, was identified, encoding mobilization and replicase proteins.
- A derivative plasmid, pEMCJH04, was successfully constructed and isolated in E. coli.
- Natural transformation of pEMCJH04 into M. catarrhalis was achieved in 25% of isolates with low efficiency.
- No correlation was found between transformability and genetic lineage or complement phenotype.
Conclusions:
- The study reports the second detailed description of a plasmid from M. catarrhalis.
- The characterized plasmid, pEMCJH04, is transformable into M. catarrhalis.
- This plasmid serves as a valuable tool for expressing foreign proteins, studying promoter activity, and conducting complementation studies, potentially aiding vaccine vector development.
