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 & Catalysis. The organization has 2143 authors who have published 3674 publications receiving 71071 citations. The organization is also known as: FFCLRP & FFCLRP-USP.

A xylose-stimulated xylanase-xylose binding protein chimera created by random nonhomologous recombination.

Abstract: Saccharification of lignocellulosic material by xylanases and other glycoside hydrolases is generally conducted at high concentrations of the final reaction products, which frequently inhibit the enzymes used in the saccharification process. Using a random nonhomologous recombination strategy, we have fused the GH11 xylanase from Bacillus subtilis (XynA) with the xylose binding protein from Escherichia coli (XBP) to produce an enzyme that is allosterically stimulated by xylose. The pT7T3GFP_XBP plasmid containing the XBP coding sequence was randomly linearized with DNase I, and ligated with the XynA coding sequence to create a random XynA–XBP insertion library, which was used to transform E. coli strain JW3538-1 lacking the XBP gene. Screening for active XBP was based on the expression of GFP from the pT7T3GFP_XBP plasmid under the control of a xylose inducible promoter. In the presence of xylose, cells harboring a functional XBP domain in the fusion protein (XBP+) showed increased GFP fluorescence and were selected using FACS. The XBP+ cells were further screened for xylanase activity by halo formation around xylanase producing colonies (XynA+) on LB-agar-xylan media after staining with Congo red. The xylanase activity ratio with xylose/without xylose in supernatants from the XBP+/XynA+ clones was measured against remazol brilliant blue xylan. A clone showing an activity ratio higher than 1.3 was selected where the XynA was inserted after the asparagine 271 in the XBP, and this chimera was denominated as XynA–XBP271. The XynA–XBP271 was more stable than XynA at 55 °C, and in the presence of xylose the catalytic efficiency was ~3-fold greater than the parental xylanase. Molecular dynamics simulations predicted the formation of an extended protein–protein interface with coupled movements between the XynA and XBP domains. In the XynA–XBP271 with xylose bound to the XBP domain, the mobility of a β-loop in the XynA domain results in an increased access to the active site, and may explain the observed allosteric activation. The approach presented here provides an important advance for the engineering enzymes that are stimulated by the final product.

Spermatophore morphology of the endemic hermit crab Loxopagurus loxochelis (Anomura, Diogenidae) from the southwestern Atlantic—Brazil and Argentina

Abstract: Summary The spermatophore morphology of the endemic and monotypic hermit crab Loxopagurus loxochelis from the southwestern Atlantic is described. The spermatophores show similarities with those described for other members of the family Diogenidae (especially the genus Clibanarius), and are composed of three major regions: a sperm-filled, circular flat ampulla; a columnar stalk; and a pedestal. The morphology and size of the spermatophore of L. loxochelis, along with a distinguishable constriction or neck that penetrates almost halfway into the base of the ampulla, are characteristic of this species. The size of the spermatophore is related to hermit crab size. Direct relationships were found between the spermatophore ampulla width, total length, and peduncle length with carapace length of the hermit crab. These morphological characteristics and size of the spermatophore of L. loxochelis are species-specific, distinguishing them from other members of the family Diogenidae, and can be used to infer phylogen...

Design of an NO photoinduced releaser xerogel based on the controlled nitric oxide donor trans-[Ru(NO)Cl(cyclam)](PF6)2 (cyclam = 1,4,8,11-tetraazacyclotetradecane)

Abstract: The immobilization and properties of the nitric oxide donor trans-[Ru(NO)Cl(cyclam)](PF(6))(2), RuNO, entrapped in a silica matrix by the sol-gel process is reported herein. The entrapped nitrosyl complex was characterized by spectroscopic (UV-vis, infrared (IR), X-ray photoelectron, and (13)C and (29)Si MAS NMR) and electrochemical techniques. The entrapped species exhibit one characteristic absorption band in the UV-vis region of the electronic spectrum at 354 nm and one IR nu(NO) stretching band at 1865 cm(-1), as does the RuNO species in aqueous solution. Our results show that trans-[Ru(NO)Cl(cyclam)](PF(6))(2) can be entrapped in a SiO(2) matrix with preservation of the molecular structure. However, in a SiO(2)/SiNH(2) matrix, the complex undergoes a nucleophilic attack by the amine group at the nitrosonium. Irradiation of the complex, entrapped in the SiO(2) matrix, with light of 334 nm, resulted in NO release. The material was regenerated to its initial nitrosyl form by reaction with nitric oxide.

Comparative Cytology of Tilapia rendalli and Geophagus brasiliensis (Cichlidae, Pisces)

Abstract: Two species of the family Cichlidae, Tilapia rendalli and Geophagus brasiliensis, live at the same ecological niche and are morphologically similar. Cytogenetic study showed a diploid complement of 44 chromosomes in the former and 48 in the latter, with the N.F. of 52 and 51, respectively. The findings suggest that they have the same origin and the difference in chromosome number may be due to chromosome rearrangements.