Effect of conditioned media on nerve cell differentiation

Summary Glial conditioned medium strongly stimulates the morphological maturation of cultured neuronal cells, while fibroblast and meningeal conditioned media have weaker effects.Acknowledgment. We acknowledge the expert technical assistance of Mrs M.F. Knoetgen.     

Regulation of non-muscle myosin assembly by calmodulin-dependent light chain kinase

The presence of actin and myosin in non-muscle cells suggests that they may be involved in a wide range of cellular contractile activities. The generally accepted view is that interaction between actin and myosin in these cells and in vertebrate smooth muscle, is regulated by the level of phosphorylation of the 20,000-molecular weight (MW) light chain. In the absence of calcium, this light chain is not phosphorylated and the myosin cannot interact with actin. Calcium activates a specific calmodulin-dependent kinase which phosphorylates the light chain, initiating actin-myosin interaction. Although most studies on the role of phosphorylation have concentration on the regulation of actin-activated myosin Mg-ATPase activity, phosphorylation of the light chain also seems to control the assembly of smooth muscle myosin into filaments. Using purified smooth muscle light chain kinase, we have confirmed this observation. We report here studies of myosins isolated from the two non-muscle sources, thymus cells and platelets. We observed that these myosins are assembled into filaments at physiological ionic strength and Mg-ATP concentrations, only when the 20,000-MW light chain is phosphorylated.     

Characterization of the domestic horse (Equus caballus) karyotype using G-and C-banding techniques

Summary Giemsa banding techniques have been used to identify the chromosomes of the domestic horse.     

Human leukocyte and fibroblast interferons are structurally related

The coding sequences of the dDNAs of cloned human leukocyte interferon I and human fibroblast interferon show homologies of 45% at the nucleotide and 29% at the amino acid level. We conclude that the two genes were derived from a common ancestor.     

Effects of thalidomide on the skeleton of the rat foetus

Zusammenfassung Nach Thalidomidverabreichung an trächtigen Ratten fanden wir Fruchtresorption und Anomalien am fünften Brustbeinkern der Föten. Weitere ergänzende Skelettuntersuchungen ergaben, besonders bei mittelgrossen Thalidomidgaben, Verknöcherungs-störungen an den Halswirbelkörpern. Andere Skeletteile zeigten keine Thalidomid-abhängigen Entwicklungsvariationen.     

Der Einfluss des Urin-pH auf die Aktivität von Urinenzymen

Summary The relationship between the pH of urine and the measured activity of ULDH, UAP and UAA was investigated in vivo and in vitro. The activity of ULDH and UAP is only half as much, or less, in acid urine (pH 4.8–5.1) as it is in alkaline urine (pH 7.0–8.1). The UAA activity, however, does not change in the pH range measured. The isoenzymes ULDH 2–4, present in alkaline urine of normal adults, does not appear in acid urine.