Altered patterns of protein phosphorylation in articular chondrocytes treated with interleukin-1 or synovial cytokines

Cultures of lapine articular chondrocytes were exposed to purified, human, recombinant interleukin-1 alpha or partially purified preparations of lapine, synovial, cytokines in the presence of [32P]orthophosphate. After 30 min incubation, phosphoproteins were extracted from the cells, separated by two-dimensional gel electrophoresis and visualized autoradiographically. Analysis of the autoradiograms revealed that interleukin-1 and the synovial factors produced marked changes in the pattern of protein phosphorylation. The synovial cytokines induced many of the same changes as interleukin-1, as well as a number of unique changes. This finding is consistent with the notion that, in addition to interleukin-1, synoviocytes secrete other cytokines which modulate the metabolism of chondrocytes. These data support the idea that signal transduction in chondrocytes responding to interleukin-1 involves the activation of one or more protein kinases.     

Enzyme production by growing cells of acinetobacter in presence of sophoroselipid and triton X-100

The effects of an extracellular microbial glycolipid, the interfacial active lactonic sophoroselipid, and of Triton X-100 on strains of Acinetobacter calcoaceticus are compared. Sophoroselipid diminished growth rates on n-heptadecane. Both surfactants led to the excretion of enzyme activities into the culture medium. Sophoroselipid increased the release of cytoplasmic malate dehydrogenase whereas in presence of Triton X-100 the quinoprotein glucose dehydrogenase was also excreted in large amounts.     

Preservation of Coombs' serum in liquid nitrogen

Experiments with Coombs-sera as raw and usable sera having different levels of titre were carried out in order to examine their stability in fluid nitrogen. Therewith, significant differences concerning the storing stability did not appear. Generally seen two third of the sera retained their initial titres at the end of one year in store.     

A 15N nuclear magnetic resonance study of the biosynthesis of quinoxaline antibiotics

Uniformly ¹⁵N-labelled triostin A and echinomycin have been prepared by growing the producing organisms on enriched media and their ¹⁵N nuclear magnetic resonance spectra partially assigned by a combination of nuclear Overhauser effect and scalar coupling constant measurements. Selective feeding experiments using unlabelled L-tryptophan-supplemented media have shown that N-1 and N-4 of the quinoxaline rings have their origins in the indole and amino groups of tryptophan, respectively.