Pettenkoferien

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In the 1930s , the German microbiologist Philalethes Kuhn described structures that he observed in bacterial cultures under certain conditions as Pettenkoferien , named after the German chemist and founder of hygiene, Max von Pettenkofer . He sat to the breeding ground of cultures lithium salts to. In addition to the original form of the bacteria , he observed the appearance of thread and spherical shapes as well as large, swollen and granulated cells , which he called A-shape . In his opinion, this represented a protozoan-like parasite that is able to penetrate the bacterial cells and live in symbiosis with them.

The large forms of these parasites, which he calls Pettenkoferien, arise from the fusion of a small form. He also observed these in his cultures in the form of tiny grains and assumed that they must be spores of the parasites. When infected bacteria disappeared, the bacterial cells would break down into irregular pieces that consist of the two forms of the parasite. His theories on the development cycle of the Pettenkoferia were of a hypothetical nature and, in contrast to his observations of the occurrence of the Pettenkoferia, were not based on experimental studies.

Historical meaning

The “invisible microbe that counteracts the dysentery bacillus” , described by the Canadian microbiologist Félix Hubert d'Hérelle in 1917 , which at that time was sometimes also referred to as the d'Hérellian phenomenon , Kuhn saw as a special case of the occurrence and multiplication of those described by him Parasites. As it turned out later, the work of d'Hérelle represented the discovery of bacteriophages , that is, viruses that infect bacteria . In contrast, Kuhn's observations were based on changes in the shape of the bacteria studied in response to the particular culture conditions he had chosen and not, as he postulated, on a parasite.

In the period from around 1920 to 1935, during which Kuhn published a series of works on the Pettenkoferien, the theory of bacterial cyclogeny, based primarily on the work of Ernst Bernhard Almquist , Felix Löhnis , Günther Enderlein and previously by Antoine Béchamp, also temporarily won in importance. This assumes an ascending and descending development cycle of all microorganisms between simpler and more complex forms with asexual or sexual reproduction depending on the morphological form , in order to explain the diversity of the different bacterial forms , which Béchamp called pleomorphism .

In contrast to this was the theory of monomorphism, which was already widely accepted at the time, which goes back primarily to Louis Pasteur and Robert Koch and which today forms the basis of microbiology. According to this view, a conversion of different types of microorganisms into one another is not possible. The different forms observed under certain conditions are merely reactions of the same bacterial species to external stimuli. In the debate between the proponents of pleomorphism and those of monomorphism, Kuhn's theory of a bacterial parasite was only a minority opinion, which was rejected by both sides.

literature

  • Philalethes Kuhn, Käte Sternberg: About bacteria and Pettenkoferien. In: Zentralblatt für Bakteriologie, Parasitenkunde and Infectious Diseases. 1. Department: Originals. 121/1931, p. 113ff
  • Philalethes Kuhn, Käte Sternberg: Further findings in bacteria and Pettenkoferien. In: Zentralblatt für Bakteriologie, Parasitenkunde and Infectious Diseases. 1. Department: Originals. 124/1932, pp. 205ff
  • Hugo von Preisz: Studies on Pettenkoferien. In: Zentralblatt für Bakteriologie, Parasitenkunde and Infectious Diseases. 1. Department: Originals. 139/1937, pp. 225ff
  • Emmy Klieneberger : Today's views of the different forms of bacterial cells of a species. In: Klinische Wochenschrift 10/1931, p. 31ff (comparative presentation and evaluation of pleomorphism, Kuhn's theory and monomorphism in the scientific context of the time)