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ABSTRACTThe mammalian host specifically limits iron duringHistoplasma capsulatuminfection, and fungal acquisition of iron is essential for productive infection. H. capsulatumexpresses several iron acquisition mechanisms under iron-limited conditions in vitro. These components include hydroxamate siderophores, extracellular glutathione-dependent ferric reductase enzyme, extracellular nonproteinaceous ferric reductant(s), and cell surface ferric reducing agent(s). We examined the relationship between these mechanisms and a potential role for the extracellular ferric reductase in utilization of environmental and host ferric compounds through the production of free, soluble Fe(II). Siderophores and ferric reducing agents were coproduced under conditions of iron limitation. The H. capsulatumsiderophore dimerum acid and the structurally similar basidiomycete siderophore rhodotorulic acid acted as substrates for the ferric reductase, and rhodotorulic acid removed Fe(III) bound by transferrin. The mammalian Fe(III)-binding compounds hemin and transferrin served both as substrates for the ferric reductase and as iron sources for yeast-phase growth at neutral pH. In the case of transferrin, there was a correlation between the level of iron saturation and efficacy for both of these functions. Our data are not consistent with an entirely pH-dependent mechanism of iron acquisition from transferrin, as has been suggested to occur in the macrophage phagolysosome. The foreign siderophore ferrioxamine B also acted as a substrate for the ferric reductase, while the foreign siderophore ferrichrome did not. Both ferrioxamine and ferrichrome served as iron sources for yeast- and mold-phase growth, the latter presumably by some other acquisition mechanism(s).

ABSTRACTFor the fungus Histoplasma capsulatum, and for other microbial pathogens, iron is an essential nutrient. Iron sequestration in response to infection is a demonstrated host defense mechanism; thus, iron acquisition may be considered an important pathogenic determinant. H. capsulatumis known to secrete Fe(III)-binding hydroxamate siderophores, which is one common microbial process for acquiring iron. Here, we report H. capsulatumferric reduction activities in whole yeast cells and in both high- and low-molecular-weight fractions of culture supernatants. Each of these activities was induced or derepressed by growth under iron-limiting conditions, a phenomenon often associated with specific iron acquisition mechanisms. The high-molecular-weight culture supernatant activity was enhanced by the addition of reduced glutathione, was proteinase K sensitive and heat labile, and could utilize ferric chloride, ferric citrate, and human holotransferrin as substrates. The low-molecular-weight culture supernatant activity was resistant to proteinase K digestion. These results are consistent with the expression by H. capsulatumof both enzymatic ferric reductase and nonproteinaceous ferric reductant, both of which are regulated by iron availability. Such components could be involved in fungal acquisition of iron from inorganic or organic ferric salts, fromH. capsulatumhydroxamate siderophores, or from host Fe(III)-binding proteins, such as transferrin.

The article reports on the performance of the motion picture industry in Eastern Europe in 2011. It is stated that "Lidice" is the only Czech film that looks likely to draw more than 200,000 viewers to theaters. Zygmunt Miloszewski's novel, "Uwiklanie," has been made into a film that is directed by Jacek Bromski in Poland. In Romania, most popular domestic film of the first half of 2011, "Nasa," has sold just 27,000 tickets in three months and lies in 42nd place in box office receipts.

The article focuses on five animated cartoons from the golden age of socialist film, the political environment that surrounded them, and their persistent popularity. As stated, the most celebrated cartoon duo in Poland was Bolek and Lolek which ran over 150 episodes from 1964 to 1986 and garnered millions of viewers through out the world. "Nu, pogodi!" was another animated television show popular in Russia and many Eastern European countries in 1969.

The article presents the author's comments on five award-winning authors including, Tea Obreht, Goce Smilevski, Mark Kharitonov, Petra Hulova, and Mircea Cartarescu. The author mentions that Obreht, who has received the 2011 Orange Prize for literature, recently sparked media attention. Various novels and their subjects of the above mentioned authors, are also discussed.