GENERAL MICROBIOLOGY - T.P. Pirog - 2004

7. PROKARYOTE SYSTEMATICS

7.4. HISTORICAL ASPECTS OF BACTERIAL SYSTEMATICS

The history of The Development of bacterial systematics spans several stages. The first attempt at a scientific Classification of Bacteria was made by the Danish zoologist O.F. Müller in 1773, who divided the 15 known species of bacteria at the time into two genera: Monas and Vibrio. In 1870, the Polish physiologist Ferdinand Cohn carried out a bacterial classification applying a morphological approach. His classification employed principles proposed by Carl Linnaeus for botanical classification. Charles Darwin's work, On THE ORIGIN OF Species, played a significant role in the subsequent development of bacterial systematics. In Darwin's works, the systematics of living organisms became evolutionary, as it was based on the common ancestry of organisms. The evolutionary theory of systematics founded by Darwin was reflected in the creation of a phylogenetic classification of higher organisms, which was supported by embryological and paleontological studies. However, these Methods could not be applied to the systematics of lower organisms.

Subsequent in-depth studies of bacterial physiology and biochemistry enabled S.N. Winogradsky and M.W. Beijerinck to propose a new approach to bacterial systematics based on a combination of morphological and physiological characteristics. In this physiological system, the primary criterion for classification was the ability of bacteria to utilize specific substrates for METABOLISM/26.html">Energy Metabolism or to excrete characteristic metabolic products. This principle was adopted by the Danish scientist S. Orla-Jensen, who in 1909 completely revised bacterial nomenclature and systematics, basing it on physiological features. At the same time, Orla-Jensen's classification was the first attempt to establish a phylogenetic classification of bacteria. For instance, he hypothesized that 4 billion years ago there were no organic substrates on Earth, and therefore the first bacteria must have been autotrophic. A second attempt was made by the Dutch scientists A.J. Kluyver and C.B. van Niel in 1936, who suggested that cocci are the most primitive bacteria because they possess the simplest morphological form; rods evolved from elongated or flattened cocci, vibrios from rods, and spirilla from vibrios.

The next stage is associated with the name of R. Buchanan, who implemented THE PRINCIPLE OF nomenclatural types in systematics. The principles of R. Buchanan, A.J. Kluyver, C.B. van Niel, and other systematists were utilized in the publication of Bergey's Manual of Determinative Bacteriology, the first edition of which was published in 1923, and the latest ninth edition in 1984 (volume one) and 1986 (volume two). Bergey's Manual is a globally recognized scientific reference work that consolidates knowledge on prokaryotic diversity. Each new edition of Bergey's Manual reflects significant advancements in the field of bacterial systematics. A large international team of leading specialists studying various groups of microorganisms collaborates on the Manual.

In 1977, a landmark study on the Taxonomy of methanogenic bacteria was published, in which, based on ribosomal RNA nucleotide sequence analysis, the authors proposed establishing a new kingdom, the Archaeobacteria. The ninth edition of Bergey's Manual of Systematic Bacteriology acknowledged that archaebacteria possess A number of unique features and that there is ample evidence indicating their evolution diverged from that of other bacteria. However, the kingdom Archaeobacteria was formally validated only in 1988.

It should be noted that a vast Amount of Information regarding new bacterial taxa has recently emerged. Publications describing new taxa can be found in the International Journal of Systematic Bacteriology, which was renamed the International Journal of Systematic and Evolutionary Bacteriology in 2000.