Spectral changes resulting from the interaction of some N-alkyl nitrosamines and rat liver microsomes

Summary Dimethyl (DMN) and diethyl nitrosamine (DEN) do not give characteristic spectral changes upon interaction with rat liver microsomes, while dipropyl (DPN) and dibutyl (DBN) nitrosamine cause type I spectral changes. The spectral binding constant is 100 mM for DPN and 1.17 mM for DBN. The maximal spectral change is 3.2×10⁶ and 1.0×10⁶ absorbance units per milligram protein for DPN and DBN respectively.Acknowledgment. This work was supported by Grants AM 13195-07 from the National Institute of Health (USA) and from the Consejo Nacional de Investigaciones Cientificas y Técnicas (Argentina).     

Deoxyribonuclease immobilized on the erythrocytes

Summary Bovine pancreatic deoxyribonuclease (DNase I) was immobilized on human erythrocytes with several procedures. DNase immobilized on the erythrocytes by chromic chloride showed DNase activity in vitro. Other binding procedures inhibit the immobilized DNase activity.     

On the nature of protein benzoquinone complexes

Summary Proteins form monosubstituted 1,4-benzoquinone derivatives with an excess of reagent via uniformly coloured charge transfer complexes. Some properties of these compounds are reported.Dedicated to Prof. J. Kühnau in commemoration of his 75th birthday.     

Purification of a nuclease from human serum

Summary The purification procedure for a nuclease from human serum is described. It includes ammonium sulfate precipitation, chromatography on DEAE-Sephadex and on Sephacryl-S 200, and preparative electrophoresis. The enzyme, purified about 2000-fold, is homogeneous in a sodium dodecyl sulfate electrophoretic system, where it has a mol. wt of 78,000. The pH optimum lies around pH 6.5; it is a sugar-nonspecific endonuclease.Acknowledgment. This work has been supported by a research grant from Stiftung Volkswagenwerk through the Akademie der Wissenschaften und der Literatur, Mainz. We thank Mrs R. Nehrbass and Mrs C. Wolpert for technical assistance.     

Semen copper in normal and infertile subjects

Summary Concentration of copper in seminal plasma was found to be less than that of normal in cases of oligospermia and azoospermia. It was more in oligoasthenospermia and asthenospermia when compared with that normal. Chances of initiation of sperm motility by copper is discussed alongwith the inhibitory role it plays.Acknowledgment. Authors are thankful to Dr. A. R. N. Setalwad, Assistant Professor in Preventive and Social Medicine for the statistical analysis of the study he did.     

Action de la capsicine sur la multiplication et la virulence de l'Agrobacterium tumefaciens

Summary It was established that the treatment of liquid cultures ofAgrobacterium tumefaciens with capsicine (in doses of 0.0025–0.01) in the course of 6 h, causes a more abundant and quicker multiplication of the micro-organism and an increase of its virulence, as measured by the method ofBernaerts andDe Ley.     

A simple method for cultivating the early chick embryo in vitro

Summary A method for cultivating the early chick embryo in an artificial medium has been developed that permits the determination of the stage at the onset of the treatment and the continuous observation of the embryogenesis.Kungliga Fysiografiska Sällskapet, Lund, supported this work.