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[Numerical taxonomy of the genus Bacillus]
R O Cinto1, M Rivas, A H Frade
1Departamento de Bioanálisis, Instituto Nacional de Farmacología y Bromatología, Buenos Aires, Argentina.
Revista Argentina De Microbiologia
|January 1, 1984
Summary
Numerical taxonomy classified seventy Bacillus strains using 81 features. The Unweighted Pair-Group Method with Arithmetic Averages (UPGMA) yielded the best classification, forming eleven groups and fourteen subgroups.
Area of Science:
- Microbiology
- Computational Biology
- Taxonomy
Background:
- The genus Bacillus is taxonomically diverse, exhibiting significant morphologic and physiological variability.
- Accurate classification of Bacillus strains is crucial for understanding their ecological roles and biotechnological applications.
Purpose of the Study:
- To classify seventy Bacillus strains using numerical taxonomy based on 81 morphologic and biochemical features.
- To evaluate different clustering methods for optimal strain differentiation.
Main Methods:
- Numerical taxonomy techniques were employed, including one coding method and four clustering methods: Weighted Pair-Group Method with Arithmetic Averages (WPGMA), Unweighted Pair-Group Method with Arithmetic Averages (UPGMA), simple linkage, and complete linkage.
- Dendrograms were generated to visualize strain relationships.
- Cophenetic correlation coefficients were calculated to assess the goodness-of-fit for each clustering method.
Main Results:
- The Unweighted Pair-Group Method with Arithmetic Averages (UPGMA) achieved the highest cophenetic correlation coefficient (0.718), indicating the most reliable classification.
- UPGMA resulted in the identification of eleven distinct groups and fourteen subgroups, defined by similarity coefficients greater than 0.700 and 0.800, respectively.
- The Weighted Pair-Group Method with Arithmetic Averages (WPGMA) dendrogram showed a highly similar distribution, corroborating the UPGMA findings.
Conclusions:
- Numerical taxonomy, particularly UPGMA, provides a robust framework for classifying Bacillus strains.
- The study confirms the inherent morphologic and physiological variability within the Bacillus genus, consistent with classical taxonomic observations.