High level of tubulin microheterogeneity in the mouse brain

Using a high resolution isoelectric focusing method, we have demonstrated a high level of tubulin heterogeneity in mouse brain: 21 isotubulins were identified. Determination of the apparent molecular weight and analysis of the peptide map of each isotubulin species allowed us to identify 7 alpha and 14 beta tubulin subunits. Furthermore, variations in this tubulin population during brain development were confirmed; in particular, an increase in the number of beta isotubulins was observed at the beginning of the postnatal period.

Serratia marcescens in tracheotomy cultures

Twenty-three consecutive tracheotomies were cultured after an apparent outbreak of Serratia marcescens was noted. Over a period of one year, six cases with positive cultures were found. The importance of these positive cultures in relation to the patient's clinical course is discussed. The treatment of Serratia marcescens septicemia is reviewed.

[The mode of action of bacteriocin N5 purified from Clostridium perfringens]

The purified bacteriocin N5 produced by Clostridium perfringens BP6K inhibited simultaneously the syntheses of DNA, RNA and protein in sensitive cells, without DNA degradation. Bacteriocin N5 inhibited the accumulation of leucin and caused the exit of the previously accumulated amino acid. The effects of bacteriocin N5 are very similar to those observed for colicins E1, K, A and I.

[Purification and characterization of "Clostridium perfringens" BP6K-N5 strain bacteriocin N5 (author's transl)]

The bacteriocin N5 produced by Clostridium perfringens, strain BP6K-N5, after UV irradiation induction, was purified by ammonium sulfate precipitation, followed by ion-exchange chromatography on DEAE cellulose and gel filtration on Sephadex G100. By polyacrylamid-gel electrophoresis and immunodiffusion analysis the purified material was shown to be homogenous. The purified bacteriocin N5 is inactivated by proteolytic enzymes and by heat treatment at 50 degrees C for 15 minutes. It is a simple protein with a molecular weight of approximately 82.000. The protein appears to be a single polypeptide chain, as no dissociation is obtained by sodium dodecyl sulfate and beta-mercaptoethanol disc-gel-electrophoresis.

Microbial content of nonsterile therapeutic agents containing natural of seminatural active ingredients

The relationship was investigated between various chemical or pharmaceutical production processes and the extent of microbial contamination, of natural origin, of the resulting products. The products contained active ingredients of vegetable, enzymatic, or animal origin. It was concluded that (i) vegetable products practically free from microbes can be produced if the proper manufacturing steps are taken; (ii) sterilization of the media used to manufacture antibiotics, etc., produces products with little contamination; and (iii) products containing extracts of animal organs require careful refrigeration and addition of preservatives to produce acceptable levels of microbial contamination.