Publications by authors named "Alberto F Ribeiro"

Aerobic exercise training (AET) has emerged as a strategy to reduce cancer mortality, however, the mechanisms explaining AET on tumor development remain unclear. Tumors escape immune detection by generating immunosuppressive microenvironments and impaired T cell function, which is associated with T cell mitochondrial loss. AET improves mitochondrial content and function, thus we tested whether AET would modulate mitochondrial metabolism in tumor-infiltrating lymphocytes (TIL).

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Purpose: Fibrillin-1 and -2 are major components of tissue microfibrils that compose the ciliary zonule and cornea. While mutations in human fibrillin-1 lead to ectopia lentis, a major manifestation of Marfan syndrome (MFS), in mice fibrillin-2 can compensate for reduced/lack of fibrillin-1 and maintain the integrity of ocular structures. Here we examine the consequences of a heterozygous dominant-negative mutation in the Fbn1 gene in the ocular system of the mgΔ mouse model for MFS.

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Most insects have a peritrophic membrane (matrix) (PM) surrounding the food bolus. This structure, similarly to the cuticle, is mainly composed of chitin and proteins. The main proteins forming PM are known as peritrophins (PMP), whereas some of the cuticle proteins are the cuticle proteins analogous to peritrophins (CPAP).

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α-Mannosidases are enzymes which remove non-reducing terminal residues from glycoconjugates. Data on both GH47 and GH38 (Golgi and lysosomal) enzymes are available. Data on insect midgut α-mannosidases acting in digestion are preliminary and do not include enzyme sequences.

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Quantitative nuclear magnetic resonance imaging (MRI) has been considered a promising non-invasive tool for monitoring therapeutic essays in small size mouse models of muscular dystrophies. Here, we combined MRI (anatomical images and transverse relaxation time constant-T2-measurements) to texture analyses in the study of four mouse strains covering a wide range of dystrophic phenotypes. Two still unexplored mouse models of muscular dystrophies were analyzed: The severely affected Largemyd mouse and the recently generated and worst double mutant mdx/Largemyd mouse, as compared to the mildly affected mdx and normal mice.

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Cockroaches are among the first insects to appear in the fossil record. This work is part of ongoing research on insects at critical points in the evolutionary tree to disclose evolutionary trends in the digestive characteristics of insects. A transcriptome (454 Roche platform) of the midgut of Periplanetaamericana was searched for sequences of digestive enzymes.

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The stromal derived factor (SDFs) family comprises a group of molecules generated by stromal cells. SDF1 and SDF4 are chemokines; SDF2 and SDF5 are not yet functionally and structurally defined. In human and mouse, Sdf2 has a paralogous gene, Sdf2l1, whose protein sequences are 78% similar and 68% identical.

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This work presents a detailed morphofunctional study of the digestive system of a phasmid representative, Cladomorphus phyllinus. Cells from anterior midgut exhibit a merocrine secretion, whereas posterior midgut cells show a microapocrine secretion. A complex system of midgut tubules is observed in the posterior midgut which is probably related to the luminal alkalization of this region.

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It has been demonstrated that variant vicilins are the main resistance factor of cowpea seeds (Vigna unguiculata) against attack by the cowpea beetle Callosobruchus maculatus. There is evidence that the toxic properties of these storage proteins may be related to their interaction with glycoproteins and other microvillar membrane constituents along the digestive tract of the larvae. New findings have shown that following interaction with the microvilli, the vicilins are absorbed across the intestinal epithelium and thus reach the internal environment of the larvae.

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Microapocrine vesicles bud from the lepidopteran midgut microvilli as double membrane vesicles. To identify the proteins secreted by this process, antibodies raised against isolated microapocrine vesicles from Spodoptera frugiperda were used for screening a midgut cDNA expression library. Positive clones were sequenced, assembled and N blasted against S.

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Musca domestica larvae present two different digestive chymotryptic activities found in the posterior midgut (PMG): one major soluble activity in the lumen and another minor present in cell membrane fractions. Both soluble and membrane-bound chymotryptic activities have different half lives of thermal inactivation (46 °C) in the presence and absence of 10 mM Triton X-100, indicating that they are two different molecular species. Purified soluble chymotryptic activity has pH optimum 7.

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Cathepsin L-like proteinases (CAL) are major digestive proteinases in the beetle Tenebrio molitor. Procathepsin Ls 2 (pCAL2) and 3 (pCAL3) were expressed as recombinant proteins in Escherichia coli, purified and activated under acidic conditions. Immunoblot analyses of different T.

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Pre-oral digestion is described as the liquefaction of the solid tissues of the prey by secretions of the predator. It is uncertain if pre-oral digestion means pre-oral dispersion of food or true digestion in the sense of the stepwise bond breaking of food polymers to release monomers to be absorbed. Collagenase is the only salivary proteinase, which activity is significant (10%) in relation to Podisus nigrispinus midgut activities.

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A cDNA coding for a digestive cathepsin L, denominated Sl-CathL, was isolated from a cDNA library of Sphenophorus levis larvae, representing the most abundant EST (10.49%) responsible for proteolysis in the midgut. The open reading frame of 972 bp encodes a preproenzyme similar to midgut cathepsin L-like enzymes in other coleopterans.

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A new species of argasid tick (Acari: Argasidae) is described from immature and adult specimens collected from several localities in Brazil. A complete morphological account is provided for all postembryonic life stages, i.e.

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Spodoptera frugiperda β-1,3-glucanase (SLam) was purified from larval midgut. It has a molecular mass of 37.5 kDa, an alkaline optimum pH of 9.

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Musca domestica larvae display in anterior and middle midgut contents, a proteolytic activity with pH optimum of 3.0-3.5 and kinetic properties like cathepsin D.

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The evolution of the digestive system in the Order Orthoptera is disclosed from the study of the morphophysiology of the digestive process in its major taxa. This paper deals with a cricket representing the less known suborder Ensifera. Most amylase and trypsin activities occur in crop and caeca, respectively.

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The tick Amblyomma parkeri Fonseca and Aragão was described in 1952, based on female and immature ticks collected in the states of São Paulo and Santa Catarina, Brazil. Thereafter, there has been no further report of A. parkeri, and the male has remained unknown.

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Adults of 3 tick species (Acari: Argasidae) identified as Antricola guglielmonei, Antricola delacruzi, and Carios rondoniensis n. sp. were collected on bat guano in a cave in the state of Rondônia, western Amazon, Brazil.

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Hemipterans are characterized by the absence of the peritrophic membrane, an anatomical structure that envelopes the food bolus in the majority of insects. However, the microvillar membranes of many hemipteran midgut cells are not in direct contact with the food bolus, due to the existence of the so-called perimicrovillar membrane (PMM), which covers the microvilli extending into the gut lumen with dead ends. alpha-Glucosidase is a biochemical marker for PMM in the seed sucker bug Dysdercus peruvianus (Heteroptera: Pyrrhocoridae).

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Bostrichiformia is the less known major series of Coleoptera regarding digestive physiology. The midgut of Dermestes maculatus has a cylindrical ventriculus with anterior caeca. There is no cell differentiation along the ventriculus, except for the predominance of cells undergoing apocrine secretion in the anterior region.

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In 2000, we initiated an investigation on the tick fauna of Rondônia State, where we collected many specimens of Amblyomma scalpturatum Neumann, 1906 and Amblyomma incisum Neumann, 1906. In addition, we also collected a third group of ticks that were morphologically closely related to those 2 species, but sufficiently different to be considered a distinct species; members of this group were subsequently identified as Amblyomma latepunctatum Tonelli-Rondelli, 1939, through comparison with the type specimens of this taxon. Herein, we redescribe both sexes of A.

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CDNAs coding for five procathepsin L-like proteinases (pCALs) were cloned and sequenced from a cDNA library prepared from Tenebrio molitor larval midguts: pCAL1a (with the isoforms pCAL1b and pCAL1c), pCAL2, and pCAL3. All the pCALs have the active residues Cys 25, His 169, Asn 175, and Gln 19 (papain numbering), the ERFNIN motif of papain-like enzymes and their sequences are homologous to cathepsin L enzymes. pCAL1a was expressed in bacterial systems.

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The Arabidopsis thaliana THI1 protein is involved in thiamine biosynthesis and is targeted to both chloroplasts and mitochondria by N-terminal control regions. To investigate thi1 expression, a series of thi1 promoter deletions were fused to the beta-glucuronidase (GUS) reporter gene. Transgenic plants were generated and expression patterns obtained under different environmental conditions.

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