Glycolipid-dependent interaction between human migration-inhibitory factor and mononuclear phagocytes

It has been previously established in the guinea pig that the response of peritoneal macrophages to migration inhibitory factor (MIF) is enhanced by a macrophage glycolipid and that gangliosides reversibly bind MIF. This suggests that glycolipids function as cell surface receptors for MIF. In this report, it is demonstrated that the response of human peripheral blood monocytes to human MIF is augmented by preincubation of these cells with glycolipidenriched material extracted from the human macrophage-like cell line U937 or human peripheral blood monocytes and with a purified glycolipid from guinea pig peritoneal macrophages. In addition, a mixed ganglioside preparation from bovine brain shows the same effect. In contrast, the pure gangliosides, G_M1 and G_D1a, and glycolipids from the HL-60 cell line, which is a MIF-unresponsive cell line, were not able to enhance the response to human MIF. The specificity of enhancement by particular glycolipids could not be attributed to an increased uptake of only enhancing glycolipids since there was no significant difference between the association of monocytes with radioactive liposomes containing biologically active or inactive glycolipids. Pronase treatment did not affect the enhancing activity of the U937 glycolipidenriched material. Incubation of cells with glycolipids results in enhancement only if done at 37 °C and not at 4 °C. Therefore, the association of lipid with the monocyte surface appears to be dependent on temperature.Further evidence for the receptor nature of these enhancing glycolipids is provided by experiments involving affinity purification experiments. Coupling of bovine brain mixed gangliosides to agarose resulted in a matrix capable of reversibly binding MIF. G_D1a-agarose was inactive in this respect.     

Die Verbreitung der limnischen MeduseMedusina limnica Müller 1978 im Rotliegenden Mitteleuropas

The fresh water medusoid fossilMedusina limnica Müller, 1978 has a large regional, but a rather restricted vertical distribution within the continental Rotliegend facies. Its main occurrence is in the higher, but not highest part of the Rotliegend supergroup in red coloured claystones, siltstones, and finegrained sandstones of Artinskian age. Any marine influence can be excluded in Rotliegend sediments of this age in the European hercynian intramontane basin. Kurzfassung: Die fossile limnische MeduseMedusina limnica Müller 1978 hat innerhalb der kontinentalen Rotliegend-Fazies (Oberkarbon-Unterperm) eine große regionale, aber eine ziemlich begrenzte vertikale Verbreitung. Ihr Hauptvorkommen liegt im höheren, aber nicht höchsten Teil des Rotliegenden in rot gefärbten Tonsteinen, Schiuffsteinen und feinkörnigen Sandsteinen, die in das Artinskian eingestuft werden können. In den varistischen Intramontanbecken Europas kann in Rotliegend-Sedimenten dieses Alters jeglicher marine Einfluß ausgeschlossen werden.     

Lineage-specific expression of c-fos and c-fms in human hematopoietic cells: Discrepancies with the in vitro differentiation of leukemia cells

In vitro differentiation studies using the bipotential human leukemia cell line, HL60, have indicated that high levels of expression of two proto-oncogenes, c-fos and c-fms, are restricted to the myelomonocytic lineage. No such expression has been detected in induced granulocytic cells. In striking contrast to these observations, we found that c-fos mRNA levels are very high in purified human granulocytes, but barely detectable in blood monocytes and tissue macrophages. Human granulocytes contain, however, relatively low levels of c-fos protein, indicating that c-fos mRNA is inefficiently translated or that the protein is rapidly degraded in these cells. In closer agreement with the in vitro results, the level of the expression of c-fms is high in purified blood monocytes and undetectable in granulocytes. We found, however, that the evolution of monocytes into tissue macrophages is accompanied by a significant decrease in c-fms expression, suggesting that the function of c-fms is restricted to specific stages of monocytic differentiation. Our observations also show that results obtained using in vitro differentiation systems have to be regarded with caution, since they may not reflect the in vivo situation.     

Comparative kinetic studies of the dealkylation reaction and steroid hydroxylations in various oxygen and carbon monoxide:oxygen atmospheres

The time-course kinetics of the cytochrome P-450-catalyzed dealkylations of the exogenous compounds benzphetamine, ethylmorphine, codeine, and 7-ethoxycoumarin were compared to the hydroxylation of the endogenous compound testosterone. Using liver microsomes from phenobarbital-induced rats, the time course of the demethylations of ethylmorphine, codeine, and especially benzphetamine was characterized by a fast initial phase of enzymatic activity and then a steady decline in the rate throughout the remainder of the reaction. In contrast, under the same experimental conditions, both the dealkylation of 7-ethoxycoumarin and the hydroxylation of testosterone showed no initial fast phase of activity and a constant rate of product formation for most of the remainder of the time course. The difference also held for the carbon monoxide inhibition studies in which the degree of inhibition of the demethylation reactions by a variety of CO:O₂ mixtures was time dependent, in contrast to the constant, time-independent degree of CO inhibition of the other two reactions. The kinetics of the demethylation reactions could not be explained by enzyme destruction, back reaction, or product adduct formation and were further confirmed by measurements of the rate of O₂ utilization and NADPH oxidation. The complexity of the demethylation reaction should be taken into consideration in any detailed studies of the monooxygenation reaction system.     

Recognition sites for a membrane-derived DNA binding protein preparation in the E. coli replication origin

Summary The DNA binding protein B' preparation, isolated from the membrane of E. coli, recognizes two sites, one of which is locatd in the minimum oriC (35–270 bp) and the other between base pairs 417 and 488. Recognition is only possible when restriction fragments containing these sites are in single-stranded state. At the first site the strand reading 3OH-5P in the direction of the E. coli genetic map is recognized, at the second site the 5P-3OH strand.     

Furanosesquiterpenes from the essential oil of myrrh

An examination of the essential oil of myrrh from Commiphora molmol has permitted the identification of 1(10)Z,4Z-furanodiene-6-one, 2-meth     

Contitions for optimal growth of a PSTV-infected potato cell suspension and detection of viroid-complementary longer-than-unit-length RNA in these cells

A suspension culture from potato spindle tuber viroid (PSTV)-infected cells of the wild type potato (Solanum demissum) has been established, which is a suitable model system for studying PSTV replicationin vivo. The conditions for rapid growth of these cells and for permanent extensive viroid biosynthesis within them are described. Biosynthesis of PSTV in the potato cells was demonstrated by³²P-incorporation into nucleic acids and their subsequent electrophoretic analysis on polyacrylamide gels. Under optimum culture conditions the amount of³²P-orthophosphate incorporation into PSTV reached 10% of that incorporated into the 2 M LiCl-soluble cellular RNA. (+)PSTV and its complementary form, i.e. (?)PSTV were identified after their electrophoretic separation on polyacrylamide and agarose gels by molecular hybridization. This analysis revealed the presence of six high molecular weight(?)PSTV species, which are possibly multimers of the unit length(+)PSTV molecule consisting of 359 nucleotides.