Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto

About: Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto is a based out in . It is known for research contribution in the topics: Population & Genus. The organization has 2143 authors who have published 3674 publications receiving 71071 citations. The organization is also known as: FFCLRP & FFCLRP-USP.

A New Baurusuchid (Crocodyliformes, Mesoeucrocodylia) from the Late Cretaceous of Brazil and the Phylogeny of Baurusuchidae

Abstract: Background Baurusuchidae is a group of extinct Crocodyliformes with peculiar, dog-faced skulls, hypertrophied canines, and terrestrial, cursorial limb morphologies. Their importance for crocodyliform evolution and biogeography is widely recognized, and many new taxa have been recently described. In most phylogenetic analyses of Mesoeucrocodylia, the entire clade is represented only by Baurusuchus pachecoi, and no work has attempted to study the internal relationships of the group or diagnose the clade and its members.

Purification and biochemical properties of a thermostable xylose-tolerant β-D-xylosidase from Scytalidium thermophilum

Abstract: The thermophilic fungus Scytalidium thermophilum produced large amounts of periplasmic β-D-xylosidase activity when grown on xylan as carbon source. The presence of glucose in the fresh culture medium drastically reduced the level of β-D-xylosidase activity, while cycloheximide prevented induction of the enzyme by xylan. The mycelial β-xylosidase induced by xylan was purified using a procedure that included heating at 50°C, ammonium sulfate fractioning (30–75%), and chromatography on Sephadex G-100 and DEAE-Sephadex A-50. The purified β-D-xylosidase is a monomer with an estimated molecular mass of 45 kDa (SDS-PAGE) or 38 kDa (gel filtration). The enzyme is a neutral protein (pI 7.1), with a carbohydrate content of 12% and optima of temperature and pH of 60°C and 5.0, respectively. β-D-Xylosidase activity is strongly stimulated and protected against heat inactivation by calcium ions. In the absence of substrate, the enzyme is stable for 1 h at 60°C and has half-lives of 11 and 30 min at 65°C in the absence or presence of calcium, respectively. The purified β-D-xylosidase hydrolyzed p-nitrophenol-β-D-xylopyranoside and p-nitrophenol-β-D-glucopyranoside, exhibiting apparent Km and Vmax values of 1.3 mM, 88 μmol min−1 protein−1 and 0.5 mM, 20 μmol min−1 protein−1, respectively. The purified enzyme hydrolyzed xylobiose, xylotriose, and xylotetraose, and is therefore a true β-D-xylosidase. Enzyme activity was completely insensitive to xylose, which inhibits most β-xylosidases, at concentrations up to 200 mM. Its thermal stability and high xylose tolerance qualify this enzyme for industrial applications. The high tolerance of S. thermophilum β-xylosidase to xylose inhibition is a positive characteristic that distinguishes this enzyme from all others described in the literature.