Hsp104 is a highly conserved protein with two essential nucleotide-binding sites

Most eukaryotic cells produce proteins with relative molecular masses in the range of 100,000 to 110,000 after exposure to high temperatures. These proteins have been studied only in yeast and mammalian cells. In Saccharomyces cerevisiae, heat-shock protein hsp104 is vital for tolerance to heat, ethanol and other stresses. The mammalian hsp110 protein is nucleolar and redistributes with growth state, nutritional conditions and heat shock. The relationships between hsp110, hsp104 and the high molecular mass heat-shock proteins of other organisms were unknown. We report here that hsp104 is a member of the highly conserved ClpA/ClpB protein family first identified in Escherichia coli and that additional heat-inducible members of this family are present in Schizosaccharomyces pombe and in mammals. Mutagenesis of two putative nucleotide-binding sites in hsp104 indicates that both are essential for function in thermotolerance.     

Migration of lymphocytes through the endothelium of venules in experimental allergic neuritis

Zusammenfassung Bei der experimentellen allergischen Neuritis verlassen die Lymphozyten das zirkulierende Blut der Venolen der peripheren Nerven, indem sie eher durch die als zwischen den Endothelzellen austreten. Der Durchtritt durch das Zytoplasma der Endothelzellen ist ein Beispiel von Emperipolesis.

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Supported by parts by NIH grant No. NB-03789-05, Inst. grant No. FRO5486-04, and a grant from the Swedish Medical Research Council. I thank Mr.L. Cherkas for help with the photography.     

A yeast prion provides a mechanism for genetic variation and phenotypic diversity

A major enigma in evolutionary biology is that new forms or functions often require the concerted effects of several independent genetic changes. It is unclear how such changes might accumulate when they are likely to be deleterious individually and be lost by selective pressure. The Saccharomyces cerevisiae prion [PSI+] is an epigenetic modifier of the fidelity of translation termination, but its impact on yeast biology has been unclear. Here we show that [PSI+] provides the means to uncover hidden genetic variation and produce new heritable phenotypes. Moreover, in each of the seven genetic backgrounds tested, the constellation of phenotypes produced was unique. We propose that the epigenetic and metastable nature of [PSI+] inheritance allows yeast cells to exploit pre-existing genetic variation to thrive in fluctuating environments. Further, the capacity of [PSI+] to convert previously neutral genetic variation to a non-neutral state may facilitate the evolution of new traits.     

Release of plasminogen activator from normal and neoplastic endometrium

Summary In the medium of endometrial carcinoma cultures, anti-urokinase-reacting plasminogen activator was released in contrast to cultures of normal or hyperplastic endometrium.This investigation was supported by grants from Malmö General Hospital, the Council for Tobacco Research, USA and the Swedish Medical Research Council (B79-17X-04523-05B).     

Lipid accumulation in mouse hepatocytes after morphine exposure

Summary After morphine injection lipid accumulation in mouse hepatocytes begins within 2 h and continues for 24 h when most hepatocytes are filled with lipid droplets. In spite of morphine maintenance the liver recovers as the accumulated lipids are coupled with protein and subsequently transported and released into the perisinusoidal space of Disse.Supported by USPHS Grants GM 15490, 5 SO7 RR05386-16 and DA-01310.     

Quantitation of fibrinolytic agents released in tissue culture

Zusammenfassung Es wird eine neue Methode zur Bestimmung der freigesetzten Menge fibrinolytisch wirksamer Stoffe in Gewebekulturen beschrieben. Das Gewebe wird in Leightonröhrchen mit einem standardisierten Fibringerinnsel gezüchtet. Die abgebaute Fibrinmenge — als Mass der fibrinolytischen Aktivität — wird durch immunologische Bestimmung der Spaltprodukte gemessen.