Type strain

A type strain is a reference strain of a microorganism used for defining its species.

Type Strain

A type strain is a reference strain of a microorganism that is used to define its species. It is the strain to which the description of the species is formally attached. Type strains are crucial in microbiology for the accurate identification and classification of microorganisms.

Definition and Importance

In microbiology, a type strain is a well-documented strain of a species that serves as the principal reference point for the species' identity. The type strain is the strain on which the description of the species is based, and it is the strain that is deposited in at least two different culture collections in different countries to ensure its availability for future research.

Type strains are important because they provide a stable reference for the identification and classification of microorganisms. They are used in taxonomic studies to compare other strains and determine whether they belong to the same species or a different one. The type strain is not necessarily the most typical or representative strain of the species, but it is the one that is used as the reference point.

Selection and Maintenance

The selection of a type strain is a critical process. It is usually the first strain of a species that is isolated and described. Once a strain is designated as the type strain, it is deposited in recognized culture collections where it is preserved and made available to researchers worldwide.

The maintenance of type strains involves careful preservation techniques to ensure their viability and genetic stability over time. Common methods include lyophilization (freeze-drying) and storage in liquid nitrogen.

Role in Taxonomy

Type strains play a central role in the taxonomy of microorganisms. They are used in the process of bacterial nomenclature and classification. When a new species is described, the type strain is designated, and its characteristics are documented in detail. This includes its morphological, physiological, and genetic properties.

The International Code of Nomenclature of Prokaryotes (ICNP) provides guidelines for the designation and use of type strains in bacterial taxonomy. According to the ICNP, a type strain must be deposited in at least two culture collections in different countries to ensure its accessibility.

Examples

- Escherichia coli K-12 is a well-known type strain used extensively in research. - Bacillus subtilis 168 is another example of a type strain that serves as a model organism in laboratory studies.

Also see

• Microbial taxonomy
• Bacterial nomenclature
• Culture collection
• International Code of Nomenclature of Prokaryotes