A structure-based site-directed mutagenesis study on the neurolysin (EC 3.4.24.16) and thimet oligopeptidase (EC 3.4.24.15) catalysis

Neurolysin (EP24.16) and thimet oligopeptidase (EP24.15) are closely related metalloendopeptidases. Site-directed mutagenesis of Tyr(613) (EP24.16) or Tyr(612) (EP24.15) to either Phe or Ala promoted a strong reduction of k(cat)/K-M for both enzymes. These data suggest the importance of both hydroxyl group and aromatic ring at this specific position during substrate hydrolysis by these peptidases. Furthermore, the EP24.15 A607G mutant showed a k(cat)/K-M of 2x10(5) M-1 s(-1) for the Abz-GFSIFRQ-EDDnp substrate, similar to that of EP24.16 (k(cat)/K-M = 3x10(5) M-1 s(-1)) which contains Gly at the corresponding position; the wild type EP24.15 has a k(cat)/K-M of 2.5x10(4) M-1 s(-1) for this substrate. (C) 2003 Federation of European Biochemical Societies. Published by Elsevier Science B.V. All rights reserved.Univ Mogi das Cruzes, CIIB, BR-08780911 Mogi Das Cruzes, SP, BrazilInst Butantan, CAT, Ctr Toxicol Aplicada, BR-05467010 São Paulo, BrazilUniv São Paulo, Inst Ciencias Biomed, Program Biol Celular, Dept Histol & Embriol, BR-05508900 São Paulo, BrazilUniversidade Federal de São Paulo, Dept Biofis, BR-04044020 São Paulo, BrazilUniversidade Federal de São Paulo, Dept Biofis, BR-04044020 São Paulo, BrazilWeb of Scienc

Does color polymorphism affect the predation risk on Phalotris lemniscatus (Duméril, Bibron and Duméril, 1854) (Serpentes, Dipsadidae)?

The snake Phalotris lemniscatus is a polymorphic species regarding color, which varies between light shades with a yellow predominance (pale yellow-brown) to darker shades with a red predominance (red-dark). Pale yellow-brown individuals are more frequent in coastal populations while there is a tendency of increasing the frequency of red-dark morphs in inland areas. Considering the variation in substrate color along the species distribution (light/sandy on the coast to reddish and dark/argillaceous in inland areas), we raise the hypothesis that the predation rate of each morph would be lower in sites were its crypsis potential is higher. If correct, this hypothesis would reinforce the idea that the predation risk is one of the factors influencing the spatial structuring in morph frequency distributions in populations of P. lemniscatus. To test this hypothesis, we performed a field experiment using plasticine P. lemniscatus artificial models that represent two morphs: red-dark and pale yellow-brown. The models were distributed in three localities where the following substrate types predominate: light (Coastal Site), intermediary (Lowland Site) and reddish dark (Highland Site). Our predictions were corroborated only at the coastal site, where the less cryptic morph was the most preyed one. We verified that there is a regional variation in the predation risk on different morphs. Thus, the possibility that the selective pressure by predators is a relevant element in the structuring of the frequencies of different morph populations of this species cannot be completely excluded

Cellular prion protein interaction with vitronectin supports axonal growth and is compensated by integrins

The physiological functions of the cellular prion protein, PrPC, as a cell surface pleiotropic receptor are under debate. We report that PrPC interacts with vitronectin but not with fibronectin or collagen. the binding sites mediating this PrPC-vitronectin interaction were mapped to residues 105-119 of PrPC and the residues 307-320 of vitronectin. the two proteins were co-localized in embryonic dorsal root ganglia from wild-type mice. Vitronectin addition to cultured dorsal root ganglia induced axonal growth, which could be mimicked by vitronectin peptide 307-320 and abrogated by anti-PrPC antibodies. Full-length vitronectin, but not the vitronectin peptide 307-320, induced axonal growth of dorsal root neurons from two strains of PrPC-null mice. Functional assays demonstrated that relative to wild-type cells, PrPC-null dorsal root neurons were more responsive to the Arg-Gly-Asp peptide (an integrin-binding site), and exhibited greater alpha v beta 3 activity. Our findings indicate that PrPC plays an important role in axonal growth, and this function may be rescued in PrPC-knockout animals by integrin compensatory mechanisms.Hosp Alemao Oswaldo Cruz, Ludwig Inst Canc Res, São Paulo, BrazilUniv São Paulo, Inst Quim, Dept Bioquim, BR-05508 São Paulo, BrazilHosp Canc, Ctr Tratamento & Pesquisa, São Paulo, BrazilUniv Fed Parana, Dept Patol Basica, BR-80060000 Curitiba, Parana, BrazilUniv Fed Parana, Dept Biol Celular, BR-80060000 Curitiba, Parana, BrazilUniversidade Federal de São Paulo, INFAR, BR-04023062 São Paulo, BrazilUniversidade Federal de São Paulo, INFAR, BR-04023062 São Paulo, BrazilWeb of Scienc

Metasurface-enhanced Light Detection and Ranging Technology

Deploying advanced imaging solutions to robotic and autonomous systems by mimicking human vision requires simultaneous acquisition of multiple fields of views, named the peripheral and fovea regions. Low-resolution peripheral field provides coarse scene exploration to direct the eye to focus to a highly resolved fovea region for sharp imaging. Among 3D computer vision techniques, Light Detection and Ranging (LiDAR) is currently considered at the industrial level for robotic vision. LiDAR is an imaging technique that monitors pulses of light at optical frequencies to sense the space and to recover three-dimensional ranging information. Notwithstanding the efforts on LiDAR integration and optimization, commercially available devices have slow frame rate and low image resolution, notably limited by the performance of mechanical or slow solid-state deflection systems. Metasurfaces (MS) are versatile optical components that can distribute the optical power in desired regions of space. Here, we report on an advanced LiDAR technology that uses ultrafast low FoV deflectors cascaded with large area metasurfaces to achieve large FoV and simultaneous peripheral and central imaging zones. This technology achieves MHz frame rate for 2D imaging, and up to KHz for 3D imaging, with extremely large FoV (up to 150{\deg}deg. on both vertical and horizontal scanning axes). The use of this disruptive LiDAR technology with advanced learning algorithms offers perspectives to improve further the perception capabilities and decision-making process of autonomous vehicles and robotic systems.Comment: 25pages, 18 figures. Including supplementary material

Metasurface-enhanced light detection and ranging technology

: Deploying advanced imaging solutions to robotic and autonomous systems by mimicking human vision requires simultaneous acquisition of multiple fields of views, named the peripheral and fovea regions. Among 3D computer vision techniques, LiDAR is currently considered at the industrial level for robotic vision. Notwithstanding the efforts on LiDAR integration and optimization, commercially available devices have slow frame rate and low resolution, notably limited by the performance of mechanical or solid-state deflection systems. Metasurfaces are versatile optical components that can distribute the optical power in desired regions of space. Here, we report on an advanced LiDAR technology that leverages from ultrafast low FoV deflectors cascaded with large area metasurfaces to achieve large FoV (150°) and high framerate (kHz) which can provide simultaneous peripheral and central imaging zones. The use of our disruptive LiDAR technology with advanced learning algorithms offers perspectives to improve perception and decision-making process of ADAS and robotic systems

Role of GP82 in the Selective Binding to Gastric Mucin during Oral Infection with Trypanosoma cruzi

Oral infection by Trypanosoma cruzi has been the primary cause of recent outbreaks of acute Chagas' diseases. This route of infection may involve selective binding of the metacyclic trypomastigote surface molecule gp82 to gastric mucin as a first step towards invasion of the gastric mucosal epithelium and subsequent systemic infection. Here we addressed that question by performing in vitro and in vivo experiments. A recombinant protein containing the complete gp82 sequence (J18), a construct lacking the gp82 central domain (J18*), and 20-mer synthetic peptides based on the gp82 central domain, were used for gastric mucin binding and HeLa cell invasion assays, or for in vivo experiments. Metacyclic trypomastigotes and J18 bound to gastric mucin whereas J18* failed to bind. Parasite or J18 binding to submaxillary mucin was negligible. HeLa cell invasion by metacyclic forms was not affected by gastric mucin but was inhibited in the presence of submaxillary mucin. Of peptides tested for inhibition of J18 binding to gastric mucin, the inhibitory peptide p7 markedly reduced parasite invasion of HeLa cells in the presence of gastric mucin. Peptide p7*, with the same composition as p7 but with a scrambled sequence, had no effect. Mice fed with peptide p7 before oral infection with metacyclic forms developed lower parasitemias than mice fed with peptide p7*. Our results indicate that selective binding of gp82 to gastric mucin may direct T. cruzi metacyclic trypomastigotes to stomach mucosal epithelium in oral infection

Desempenho de bezerras leiteiras das raças Pantaneira e Girolando suplementadas ou não durante o período de estiagem na região de Alto-Pantanal Sul-Mato-Grossense.

Utilizou-se 24 bezerras desmamadas, distribuídas em dois grupos (raças) com doze animais, por um período de avaliação foi de 94 dias (14 dias de adaptação e três sub-períodos de 28 dias). Os animais foram mantidos em piquetes de capim braquiária (Brachiaria decumbens), em sistema de pastoreio rotacionado. Os tratamentos foram: 1- Pastagem; 2- Suplementado com concentrado (1% peso corpóreo); 3- Suplementado com concentrado mais um aditivo melhorador das funções orgânicas (AMFO); 4- Tratado somente com AMFO (4 injeções de 20 ml). Não houve diferenças estatísticas entre as raças no ganho de peso dos animais, com média de 140,8 e 150,8 gramas/dia para o grupo não suplementado com concentrado e de 321,6 e 448,5 gramas/dia para o grupo suplementado das raças Pantaneira e Girolando, respectivamente. O AMFO não promoveu efeitos significativos (P>0,05) nas variáveis analisadas

Challenges for sustainable monitoring and evaluation of the EU Marine Strategy Framework Directive in the Atlantic offshore waters: the iFADO project

The European Atlantic Area in situ characterization/monitoring is challenging due to the high costs involved (24% of total EU waters for 12% of total population). The implementation of the EU Marine Strategy Framework Directive (MSFD) is complex if the objective is to extend periodic monitoring programs to offshore waters. Remote sensing and modelling have been recognised by the Copernicus Marine Service as suitable methodologies to characterise the global ocean both for nowcast and forecast. iFADO (Innovation in the Framework of the Atlantic Deep Ocean, 2017-2021) is an Interreg Atlantic Area project which main objective is to integrate technologies, including remote sensing, numerical modelling and in situ monitoring, to ease management decisions from MSFD competent authorities. The iFADO project builds on the most recent technologies for data gathering and processing, suited for providing sustainable services to blue economy agents by fostering the regional quadruple helix cooperation (public sector, university/research centres, enterprise and citizens).info:eu-repo/semantics/publishedVersio