Hypoxia adaptation in fish of the Amazon: a never-ending task

In addition to seasonal long-term changes in dissolved oxygen and carbon dioxide, water bodies of the Amazon present periodic short-term episodes of hypoxia and even anoxia. To preserve gas exchange and acid base balance, fish of the Amazon have developed multiple adaptive solutions which occur at all biological levels. These solutions are thought to represent adaptive convergence rather than phylogenetic relatedness. Fish of the Amazon exposed to different experimental conditions adjust, for example, several parameters to improve oxygen transfer from the gas-exchange site to the tissues. These parameters include morphological changes such as the development of the lower lip in Colossoma, changes in ventilation rates, changes in circulatory parameters, increased circulating red blood cells, decreased levels of intraerythrocytic phosphates, and adjustments of intraerythrocytic pH (pHi). These adjustments that allow fish to survive both short- and long-term hypoxia occur in different degrees in different fish species and may or may not occur simultaneously. In addition, these adjustments in oxygen transfer affect many other parameters, particularly acid-base status. We suggest that these adjustments are initiated as soon as the animal detects the environmental change in oxygen availability and are mediated by a single factor, possibly one of the catecholamines. In this paper we aim to show that adaptation to hypoxia is a never-ending task for the fish of the Amazon

Slowly synchronizing automata and digraphs

We present several infinite series of synchronizing automata for which the minimum length of reset words is close to the square of the number of states. These automata are closely related to primitive digraphs with large exponent.Comment: 13 pages, 5 figure

Genetic characterization of interleukins (IL-1α, IL-1β, IL-2, IL-4, IL-8, IL-10, IL-12A, IL-12B, IL-15 and IL-18) with relevant biological roles in lagomorphs

Disponível em: www.ncbi.nlm.nih.gov/pmc/articles/pmid/26395994/ILs, as essential innate immune modulators, are involved in an array of biological processes. In the European rabbit (Oryctolagus cuniculus) IL-1α, IL-1β, IL-2, IL-4, IL-8, IL-10, IL-12A, IL-12B, IL-15 and IL-18 have been implicated in inflammatory processes and in the immune response against rabbit hemorrhagic disease virus and myxoma virus infections. In this study we characterized these ILs in six Lagomorpha species (European rabbit, pygmy rabbit, two cottontail rabbit species, European brown hare and American pika). Overall, these ILs are conserved between lagomorphs, including in their exon/intron structure. Most differences were observed between leporids and American pika. Indeed, when comparing both, some relevant differences were observed in American pika, such as the location of the stop codon in IL-1α and IL-2, the existence of a different transcript in IL8 and the number of cysteine residues in IL-1β. Changes at N-glycosylation motifs were also detected in IL-1, IL-10, IL-12B and IL-15. IL-1α is the protein that presents the highest evolutionary distances, which is in contrast to IL-12A where the distances between lagomorphs are the lowest. For all these ILs, sequences of human and European rabbit are more closely related than between human and mouse or European rabbit and mouse.Research Subject Categories::NATURAL SCIENCES::Biology::Cell and molecular biology::ImmunologyResearch Subject Categories::NATURAL SCIENCES::Biology::Cell and molecular biology::GeneticsFCT and North Portugal Regional Operational Programme 2007/2013 (ON.2) grants supported this work

Influence of the PAni morphology deposited on the carbon fiber: An analysis of the capacitive behavior of this hybrid composite

AbstractCF/PAni composites were synthesized using the polymerization chemistry. Three different deposition times were used in the synthesis, such as: 30, 60 and 90min. The morphology and the structure of composites were analyzed by SEM and Raman spectroscopy, respectively. The influence of the mass of polymer deposited on the carbon fiber, with respect to the values of specific capacitance (Csp) was analyzed by electrochemical experiments. The optimum value of the Csp was obtained for CF/PAni-30min (Csp=188Fg−1). This fact is related to the lower charge transfer resistance, due to its more homogeneous morphology and thin layer polyaniline

Activity-regulated cytoskeleton-associated protein controls AMPAR endocytosis through a direct interaction with clathrin-adaptor protein 2

The activity-regulated cytoskeleton-associated (Arc) protein controls synaptic strength by facilitating AMPA receptor (AMPAR) endocytosis. Here we demonstrate that Arc targets AMPAR to be internalized through a direct interaction with the clathrin-adaptor protein 2 (AP-2). We show that Arc overexpression in dissociated hippocampal neurons obtained from C57BL/6 mouse reduces the density of AMPAR GluA1 subunits at the cell surface and reduces the amplitude and rectification of AMPAR-mediated miniature-EPSCs (mEPSCs). Mutations of Arc, that prevent the AP-2 interaction reduce Arc-mediated endocytosis of GluA1 and abolish the reduction in AMPAR-mediated mEPSC amplitude and rectification. Depletion of the AP-2 subunit µ2 blocks the Arc-mediated reduction in mEPSC amplitude, an effect that is restored by reintroducing µ2. The Arc-AP-2 interaction plays an important role in homeostatic synaptic scaling as the Arc-dependent decrease in mEPSC amplitude, induced by a chronic increase in neuronal activity, is inhibited by AP-2 depletion. These data provide a mechanism to explain how activity-dependent expression of Arc decisively controls the fate of AMPAR at the cell surface and modulates synaptic strength, via the direct interaction with the endocytic clathrin adaptor AP-2

O sucesso de três anos do serviço IBGEPPP

Até o início de 2009, os pro ssionais que fazem uso das técnicas de posicionamento por satélites no desenvolvimento de suas atividades necessitavam de um programa de processamento de observações GPS gratuito, que calculasse de forma precisa as coordenadas dos levantamentos realizados. Em abril desse mesmo ano, o IBGE através da Coordenação de Geodésia, disponibilizou o serviço online IBGE-PPP, atendendo essa demanda e se tornando o primeiro país da América Latina a oferecer esse serviço gratuitamente. Em três anos de funcionamento, o IBGE-PPP já atendeu mais de 9.500 usuários, processando 127.352 arquivos de observações GPS. Este trabalho apresenta as principais características do serviço, além de fazer uma avaliação dos processamentos realizados pelos usuários, a precisão obtida nos processamentos,bem como as futuras implementações visando melhores resultados

Cissus Sicyoides: Pharmacological Mechanisms Involved In The Anti-inflammatory And Antidiarrheal Activities

The objective of this study was to evaluate the pharmacological mechanisms involved in anti-inflammatory and antidiarrheal actions of hydroalcoholic extract obtained from the leaves of Cissus sicyoides (HECS). The anti-inflammatory effect was evaluated by oral administration of HECS against acute model of edema induced by xylene, and the mechanisms of action were analysed by involvement of arachidonic acid (AA) and prostaglandin E2 (PGE2). The antidiarrheal effect of HECS was observed and we analyzed the motility and accumulation of intestinal fluid. We also analyzed the antidiarrheal mechanisms of action of HECS by evaluating the role of the opioid receptor, α2 adrenergic receptor, muscarinic receptor, nitric oxide (NO) and PGE2. The oral administration of HECS inhibited the edema induced by xylene and AA and was also able to significantly decrease the levels of PGE2. The extract also exhibited significant anti-diarrheal activity by reducing motility and intestinal fluid accumulation. This extract significantly reduced intestinal transit stimulated by muscarinic agonist and intestinal secretion induced by PGE2. Our data demonstrate that the mechanism of action involved in the anti-inflammatory effect of HECS is related to PGE2. The antidiarrheal effect of this extract may be mediated by inhibition of contraction by acting on the intestinal smoothmuscle and/or intestinal transit. © 2016 by the authors; licensee MDPI, Basel, Switzerland.17

Signatures of Primordial non-Gaussianities in the Matter Power-Spectrum and Bispectrum: the Time-RG Approach

We apply the time-renormalization group approach to study the effect of primordial non-Gaussianities in the non-linear evolution of cosmological dark matter density perturbations. This method improves the standard perturbation approach by solving renormalization group-like equations governing the dynamics of gravitational instability. The primordial bispectra constructed from the dark matter density contrast and the velocity fields represent initial conditions for the renormalization group flow. We consider local, equilateral and folded shapes for the initial non-Gaussianity and analyze as well the case in which the non-linear parameter f_{NL} parametrizing the strength of the non-Gaussianity depends on the momenta in Fourier space through a power-law relation, the so-called running non-Gaussianity. For the local model of non-Gaussianity we compare our findings for the power-spectrum with those of recent N-body simulations and find that they accurately fit the N-body data up to wave-numbers k \sim 0.25 h/Mpc at z=0. We also present predictions for the (reduced) matter bispectra for the various shapes of non-Gaussianity.Comment: 27 pages, 12 figures. Results and discussion for a particular case added. One figure and one reference added. Matches with the version accepted for publication in the JCAP