196,196 research outputs found
Chudožestvennyj tekst i ego geo-kul’turnye stratifikacii, ed. by M. C. Pesenti, M. De Michiel, P. Deotto, M. Nortmann, I. Verc, “Slavica Tergestina”, 8, 2000.
No full textM. Ferrazzi, Commedia e comici dell’arte italiani alla corte russa (1731-1738), Bulzoni, Roma, 2000.
No full text
Da Pietro I a Caterina II. Un aneddoto petrino fra le righe della commedia "L’onomastico della signora Vorchalkina"
No full textCharacterization of a beta-glycosidase from the thermoacidophilic bacterium Alicyclobacillus acidocaldarius.
No full textIn cell free extracts of the thermoacidophilic gram-positive bacterium Alicyclobacillus acidocaldarius ATCC27009, we have identified beta-gluco- and galactosidase activities showing a specific activity of 0.1 and 12 U/mg, respectively. The two enzymatic activities are associated with different polypeptides and we show here the functional cloning, the expression in Escherichia coli and the characterisation of the beta-glucosidase (Aabeta-gly). The enzyme, which is optimally active and stable at temperatures above 65 degrees C, belongs to glycoside hydrolase family 1 (GH1) and shows wide substrate specificity on different aryl-glycosides and cello-oligosaccharides with k (cat)/K (M) for 4-nitrophenyl-beta-D-glucoside and cellobiose of 2,976 and 185 s(-1)mM(-1), respectively. Interestingly, upstream to the beta-glycosidase gene, we identified a second ORF homologous to the ATPase subunit of the bacterial ABC transporters (abc1) that is co-transcribed with the beta-glycosidase gene glyB and that could be involved in the carbohydrate import. The activity of the enzyme on cello-oligosaccharides of up to five glucose units strongly indicates that the enzyme could be involved in vivo in the degradation of glucans together with endoglucanase enzymes previously described. This, together with the co-expression of the two genes, suggests a role for the glyB-abc1 cluster in A. acidocaldarius in the degradation of cellulose and hemicelluloses
Remarkable ecological and physiological diversity of the hyperthermophiles populating neighboring solfataric pools revealed by metagenomic analysis
No full textThe study of the complex communities of hyperthermophiles, composed of Bacteria, Archaea, and viruses, populating volcanic sites is of interest to understand their adaptation and evolution to extreme conditions and as a rich source of biocatalysts [1, 2]. In fact, the intrinsic stability of their enzymes to common protein denaturants made them interesting tools for biotransformations in industrial applications.
In the framework of the discovery of new enzymes for biocatalysis and biotransformations, we decided to explore the diversity of the solfataric field of Pisciarelli, Agnano (Naples, Italy), by performing a metagenomic analysis of the microbial community living in two mud/water pools that, although distant only 4.0 meters, greatly differ in both temperature and pH (T=85°C and pH 5.5; T=94°C and pH 1.5, for Pool1 and Pool2, respectively). In particular, DNA from Pool1 was extracted from the mud/water suspension while Pool2 DNA was obtained from the sediment. The deep sequencing by Illumina technology and the following in-silico analysis showed that the phylum Crenarcheaota was prevalent, but with great genera variance in the two pools according to the different environmental T and pH. The analysis of the functional categories revealed that genes involved in the carbohydrate metabolism were prevalent, followed by amino acid metabolism and by membrane transporters. The detailed phylogenetic and physiological analysis of the samples will be discussed together with the possible mechanisms of selection occurred in the two extremophilic environments.
Bibliography
1. Cobucci-Ponzano B., Aurilia V., Riccio G., Henrissat B., Coutinho P.M., Strazzulli A., Padula A., Corsaro M.M., Pieretti G., Pocsfalvi G., Fiume I., Cannio R., Rossi M., and Moracci M.: J Biol Chem, 2010, 20691-20703.
2. Cobucci-Ponzano, B., Conte, F., Strazzulli, A., Capasso, C., Fiume, I., Pocsfalvi, G., Rossi, M., Moracci.: M. Biochimie, 2010, 92, 1895-907
I. Reyfman, Vasilii Trediakovsky. The Fool of the “New” Russian Literature, Stanford (Ca), Stanford University Press (1990), 316 pp.; M. S. Grinberg – B. A. Uspenskij, Literaturnaja vojna Trediakovskogo i Sumarokova v 1740-ch- nachale 1750-ch godov, “Russian Literature”, XXXI-XXXII, 1992
No full textOxalacetate decarboxylase and pyruvate carboxylase activities, and effect of sulfhydryl reagents in malic enzyme from Sulfolobus solfataricus.
No full textMalic enzyme (S)-malate: NADP+ oxidoreductase (oxaloacetate-decarboxylating, EC 1.1.1.40) purified from the thermoacidophilic archaebacterium Sulfolobus solfataricus, strain MT-4, catalyzed the metal-dependent decarboxylation of oxaloacetate at optimum pH 7.6 at a rate comparable to the decarboxylation of L-malate. The oxaloacetate decarboxylase activity was stimulated about 50% by NADP but only in the presence of MgCl2, and was strongly inhibited by L-malate and NADPH which abolished the NADP activation. In the presence of MnCl2 and in the absence of NADP, the Michaelis constant and Vm for oxaloacetate were 1.7 mM and 2.3 mumol.min-1.mg-1, respectively. When MgCl2 replaced MnCl2, the kinetic parameters for oxaloacetate remained substantially unvaried, whereas the Km and Vm values for L-malate have been found to vary depending on the metal ion. The enzyme carried out the reverse reaction (malate synthesis) at about 70% of the forward reaction, at pH 7.2 and in the presence of relatively high concentrations of bicarbonate and pyruvate. Sulfhydryl residues (three cysteine residues per subunit) have been shown to be essential for the enzymatic activity of the Sulfolobus solfataricus malic enzyme. 5,5'-Dithiobis(2-nitrobenzoic acid), p-hydroxymercuribenzoate and N-ethylmaleimide caused the inactivation of the oxidative decarboxylase activity, but at different rates. The inactivation of the overall activity by p-hydroxymercuribenzoate was partially prevented by NADP singly or in combination with both L-malate and MnCl2, and strongly enhanced by the carboxylic acid substrates; NADP + malate + MnCl2 afforded total protection. The inactivation of the oxaloacetate decarboxylase activity by p-hydroxymercuribenzoate treatment was found to occur at a slower rate than that of the oxidative decarboxylase activity
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