7.2
Mikrobielle Klassifikationssysteme
Unter Klassifikation versteht man den Prozess der Einteilung von Organismen in hierarchisch umfassende Gruppen auf der Grundlage ihrer phänotypischen…
Die mikrobielle Klassifikation umfasst die systematische Kategorisierung von Mikroorganismen in zunehmend inklusivere Gruppen auf der Grundlage ihrer phänotypischen Ähnlichkeit oder evolutionären Beziehungen.
Die Benennung von Organismen erfolgt nach dem von Carl Linnaeus entwickelten Binomialsystem. Dieses System ist hierarchisch, mit Taxa, die von Domäne zu Art organisiert sind.
Zum Beispiel enthält die Domäne Bacteria ein Phylum Proteobakterien. Des Weiteren umfasst sie die Ordnung Chromatiales. Eine von mehreren Familien in dieser Ordnung ist die Familie der Chromatiaceae, die aus der Gattung Allochromatium besteht. Unter dieser Gattung werden sieben gültige Arten beschrieben, von denen eine warmingii ist.
Das Internationale Komitee für die Systematik der Prokaryoten regelt die Nomenklatur und Taxonomie von Bakterien und Archaeen und gewährleistet die Genauigkeit der mikrobiellen Klassifizierung.
Die gültigen und genehmigten Bakteriennamen werden regelmäßig in die LPSN-Datenbank List of Prokaryotic Names with Standing in Nomenclature (LPSN) aufgenommen.
Darüber hinaus ist Bergey's Manual of Systematic Bacteriology eine wichtige Quelle für verschiedene Aspekte von Bakterien und Archaeen.
View the full transcript and gain access to JoVE Core videos
Q1: What is the binomial nomenclature system used in microbial classification?
The binomial system, developed by Carl Linnaeus, assigns each organism a genus name and species epithet written in italics. This two-part naming convention provides a standardized way to identify microorganisms. For example, Allochromatium warmingii uses Allochromatium as the genus and warmingii as the species epithet, enabling precise scientific communication across the microbiology field.
Q2: How are microorganisms organized in the taxonomic hierarchy?
Microorganisms are classified into progressively more inclusive groups based on phenotypic similarity or evolutionary relationships. The hierarchy progresses from Domain at the broadest level, through Phylum, Class, Order, Family, Genus, and finally Species at the most specific level. For instance, the Domain Bacteria includes Phylum Proteobacteria, which contains Order Chromatiales, demonstrating how taxa nest hierarchically.
Q3: What role does the International Committee on Systematics of Prokaryotes play in microbial naming?
The International Committee on Systematics of Prokaryotes (ICSP) governs the nomenclature and taxonomy of bacteria and archaea, ensuring accuracy and standardization in microbial classification. This committee oversees the International Code of Nomenclature of Bacteria, which outlines formal procedures for validating new species names and maintaining consistency across the scientific community.
Q4: What is the Candidatus designation used for in microbial nomenclature?
The Candidatus prefix is assigned to provisional names for organisms that cannot yet be cultured or obtained in pure form. Examples include Candidatus Pelagibacter ubique, a widespread bacterial species difficult to grow in laboratories, and Candidatus Heliomonas lunata, which cannot be maintained as a pure culture. This designation acknowledges valid species while indicating cultivation limitations.
Q5: Where can microbiologists find validated lists of bacterial and archaeal names?
Validated bacterial and archaeal names are maintained in the List of Prokaryotic Names with Standing in Nomenclature (LPSN) database and Prokaryotic Nomenclature Up-to-Date. Bergey's Manual of Systematic Bacteriology, published since 1923, remains the most widely recognized classification system, offering detailed information, systematic tables, and identification tools for bacteria and archaea.
Q6: What is the importance of microbial culture collections in taxonomy?
National microbial culture collections, such as the American Type Culture Collection, preserve viable cultures in conditions that maintain genetic integrity. These repositories store type strains that serve as reference points for future taxonomic comparisons, enabling continued study and characterization. Unlike museum specimens, living cultures support ongoing research and safeguard microbial biodiversity.
Q7: What requirements must be met to validate a new bacterial species name?
A new bacterial species name must be accompanied by a detailed description of distinguishing characteristics and viable culture deposits in at least two international repositories. These requirements ensure that new taxa are properly documented and accessible for verification by other researchers. The validation process is governed by the International Code of Nomenclature of Bacteria to maintain taxonomic accuracy.