[Occurrence of neuraminidase in Sporothrix schenckii and Ceratocystis stenoceras and its role in ecology and pathomechanism of these fungi (author's transl)].

Some strains of Sporothrix schenckii and one strain of Ceratocystis stenoceras were investigated and the occurrence of the enzyme neuraminidase (= sialidase, N-acetylneuraminate glycohydrolase, EC 3.2.1.18) was proved not only by Warren's thiobarbituric acid assay but also by immunoelectrophoresis technique using monospecific antisera against 25 human glycoproteins, lipoproteins, immunoglobulins, fibrinogen and some other proteins (Table 1). There are also fibrinolytic and lipolytic enzyme activities in strains of Sporothrix chenckii corresponding with similar findings of other authors and also in the Ceratocystis stenoceras strain. The temperature optimum of production of neuraminidase seems to be lower than 37 degrees C (Table 2) and all strains failed to produce the enzyme after cultivation at 37 degrees C during some months. The findings of the existence of neuraminidase in the both species confirm also their close relationship. Because the occurrence of N-acylneuraminate was shown only in animals and in some microorganisms but not in plants it can be suggested that also Sporothrix schenckii and Ceratocystis stenoceras grow on animal or neuraminate containing microbial material but not on plants as it is assumed hitherto. Corresponding to this hypothesis the pathogenicity of Sporothrix schenckii and also the facultative pathogenicity of Ceratocystis stenoceras are to see in connexion with the action of neuraminidase and other enzymes metabolizing animal substrates. It can be concluded that neuraminidase is a possible additional pathogenic factor in sporotrichosis below 37 degrees C.