Frequency of cytokine-producing CD4-CD8- peripheral blood mononuclear cells in patients with Plasmodium falciparum malaria.

The frequency of cytokine-producing CD4-/CD8- mononuclear cells was assessed in patients of different age groups (29 infants, aged 1-5 years; 30 schoolchildren, aged 6-14 years, 26 adults, aged > 15 years) with acute Plasmodium falciparum malaria, from Gabon. Fifteen patients were followed up before antimalarial treatment (day 0), during parasite clearance (day 3) and after resolution of parasitemia (day 10). By using flow cytometry for intracellular detection of cytokines, a striking expansion of CD4-/CD8- cells producing the type 1 cytokines interleukin (IL)-2-/interferon (IFN)-gamma+, IL-2+/IFN-gamma+ and IL-2+/IFN-gamma- was observed in adults as compared with children. Type 2 cytokine expression (IL-4+/IFN-gamma-, IL-13+/IFN-gamma-) and type 0 cells (IL-4+/IFN-gamma+, IL-13+/IFN-gamma+) were not significantly different between the three age groups. Patients with severe malaria had a significantly increased frequency of type 2 cytokine-producing CD4-/CD8- cells. Drug-induced clearance of parasitemia was characterized by a decrease of IL-2+/IFN-gamma- and type 2 cytokine expressing CD4-/CD8- cells and by a gradual increase of IL-10+/IFN-gamma- expression. The type 1/type 2 dichotomy observed within the CD4-/CD8- cell population is likely to be of significance in the host response against P. falciparum malaria.     

Properties of Some Diuridine Phosphate Analogues

Abstract

The hydrolytic stability of oligoribonucleotides containing 2′- amino nucleophile is due to poor leaving characteristic of 5′-nucleoside, replacement of 5′-leaving group by thio or amino results in considerable instability towards hydrolysis.     

Übereinstimmung positiver und negativer Dopareaktiönen an Gefrierschnitten mit jenen an Extrakten

Zusammenfassung WährendChodat (1922),Meirowsky (1923) undPrzibram (1921) eine spezifische Dopaoxydase ablehnen, da nach des letzteren Befunden das 3, 4 Dioxyphenylalanin sowohl spontan als auch bei Alkali- oder Tyrosinasezusatz sich schwärzt, hältBloch an der Spezifität der Dopase und an ihrem Nachweis durch Dopazusatz fest. Gegenüber den vergeblichen Versuchen, die Dopase zu isolieren, beruft er sich auf die Verschiedenheit der benutzten Methoden. Diesen Einwand könnte er auch den VersuchenSatos undBrechers (1923 u. d. Heft) wegen des ebenfalls negativen Ausfalles der für Dopa charakteristischen Reaktionen (mit Eisenchlorid Grünfärbung, dann bei Natriumkarbonatzusatz Umschlag nach Purpurrot usw.) in den Extrakten der melaninbildenden Gewebe machen. Seiner Forderung nach Anwendung der Gefrierschnittmethode folgend, wurden nur solche namentlich von denselben Objekten, die er verwendet hatte, mikrochemisch auf Dopa untersucht. Weder Augen noch schwarze oder weiße Stellen einer 7 Tage alten oder älteren Ratte noch die Kopfhaut von Menschen zeigten die erwähnte Grünbzw. Rotfärbung. Ebenso negativ fielen die analogen Proben an Puppen verschiedenen Farbtypus vonVanessa urticae aus, ferner am Kokon desBombyx mori.Hingegen zeigten die Gefrierschnitte der Kokone vonSaturnia pavonia undEriogaster lanestris, an denenPrzibram (1922) mittels Extraktion durch Wasser den Dopanachweis in der Eprouvette erbracht hatte, deutlich positiven Ausfall.Es besteht demnach keine Veranlassung, einen Unterschied in der Feststellbarkeit von Dopa anzunehmen, je nachdem man Gefrierschnitt oder Extrakt untersucht.Ein Auszug dieser Arbeit erschien unter dem Titel: Mitteilungen aus der Biologischen Versuchsanstalt der Akademie der Wissenschaften, Zoologische Abteilung, VorstandH. Przibram, Nr. 108. Übereinstimmung positiver und negativer Dopareaktionen an Gefrierschnitten mit jenen an Extrakten (zugleich: Ursachen tierischer Farbkleidung. XI) vonLeonore Brecher undFerdinand Winkler im Akademischen Anzeiger der Akademie der Wissenschaften in Wien, Nr. 17, 1923.     

Interaction of extracellular Pseudomonas lipase with alginate and its potential use in biotechnology

Summary Extracellular Pseudomonas lipase is able to interact directly or indirectly with alginate as deduced from the following results: (i) During adsorption chromatography of exolipase the enzyme adsorbed quantitatively to glass beads in the absence of alginate, but not after its preincubation in the presence of the polysaccharide; pretreatment of glass beads with alginate did not prevent enzyme adsorption. (ii) In the presence of alginate exolipase was much more resistant to heat inactivation than in its absence. (iii) In the presence of alginate the increase in exolipase activity caused by the non-ionic detergent Triton X-100 was drastically reduced. (iv) Exolipase could be rapidly and almost completely harvested from cell-free culture fluid of P. aeruginosa 5940 by ethanolic coprecipitation with alginate. After dissolving the coprecipitate in detergent-containing buffer exolipase and polysaccharide could be easily separated by ion-exchange chromatography on DEAE-Sephadex A-25. The coprecipitation method was also successfully applied to exolipases produced by Pseudomonas sp., Chromobacierium viscosum and Rhizopus delamar, thus suggesting potential use of this method in biotechnology.     

Dityrosine is a prominent component of the yeast ascospore wall. A proof of its structure

The yeast ascospore wall consists of four morphologically distinct layers. The hydrophobic surface layers are biogenically derived from the prospore wall and appear dark after OsO4 staining. They seem to be responsible for the stability of the spores against attack by lytic enzymes. By amino acid analysis of acid hydrolysates of ascospore walls, two new peaks were detected, which were shown to be the racemic and meso form, respectively, of dityrosine. The identity of this hitherto unknown component of the yeast ascospore wall with standard dityrosine was proven by 1H NMR and by mass spectrometry. A 13C NMR spectroscopic investigation of the structure of dityrosine confirmed that, in natural dityrosine, the biphenyl linkage is located ortho, ortho to the hydroxyl groups. Following digestion of the inner layers of isolated ascospore walls it was shown that dityrosine is very probably located only in the surface layers. The same conclusion was reached independently by an investigation of spores of a strain homozygous for the mutation gcn1, which lack the outermost layers of the spore wall and were practically devoid of dityrosine. In sporulating yeast, L-tyrosine was readily incorporated into the dityrosine of the ascospore wall. Control experiments involving vegetative a/alpha cells and nonsporulating alpha/alpha cells under sporulation conditions showed that dityrosine is indeed sporulation-specific.