[Physiological and cell biological characterization of the protease producer Thermoactinomyces vulgaris during prolonged culture in a stirred fermenter]. / Physiologische und zellbiologische Charakterisierung des Proteasebildners Thermoactinomyces vulgaris während Langzeit-Kultivation im Rührfermentor.

The physiological behaviour of Thermoactinomyces vulgaris - producing a thermostable serine-protease - was analyzed during fermentation. During 38 h the consumption of nutrients and oxygen as well as the rates of macromolecular and protease synthesis were measured. The morphological and ultrastructural changes of the mycelia were also studied. The mycelia grew exponentially for about 5 hours. After a short lag and a second slower growth phase, growth continued about linearly until the end, as was indicated by a constant rate of incorporation of labelled thymidine. However, at the same time a changing portion of hyphae - up to 45% - underwent lysis. According to the changing ratio of growing and lysing material, regarding the physiological activity of the culture the fermentation process could be divided into 4 periods. The formation of the protease started at the transition to the slow growth phase and continued linearly. The ability to produce the protease was attributed to a mycelium being formed after the shift down caused by limitation of supply of utilizable nitrogen compounds. The end of protease production 10 h later was correlated to a drastic decrease of the respiratory activity of the mycelia, probably caused by exhaustion of easily utilizable carbohydrates.

[Incorporation of thymidine into the DNA of actinomycetes. I. Incorporation of exogenous thymidine into the DNA of Thermoactinomyces vulgaris]. / Einbau von Thymidin in die DNS von Actinomyceten. I. Der Einbau exogenen Thymidins in die DNS von Thermoactinomyces vulgaris.

The incorporation of exogenous thymidine and thymine into acid-insoluble material of Thermoactinomyces vulgaris has been studied during germination and subsequent growth. Thymine is not incorporated. The incorporation of thymidine stops after a short time due to the rapid breakdown of thymidine to thymine and deoxyribose-1-phosphate by the inducible thymidine phosphorylase. Deoxyadenosine enhances the incorporation of thymidine as well as of thymine and prolongs the tine of uptake. Uridine stimulates only the incorporation of thymidine but not of thymine. These effects can be explained by the function of these substances within the salvage pathway. Deoxyadenosine acts as donor of deoxyribosyl groups being necessary for the conversion of thymine to thymidine by thymidine phosphorylase and uridine inhibits thymidine phosphorylase, and thereby it prevents the degradation of thymidine to thymine. Thymidine is incorporated into alkali-, RNase-and protease-stable, hot TCA-soluble and DNase-sensitive material. That means that the cellular DNA of T. vulgaris can be specifically labelled by radioactive thymidine in the presence of deoxyadenosine and uridine, respectively.