14 research outputs found
Combate ao Aedes Aegypti e investigação epidemiolĂłgica de dengue na ĂĄrea de abrangĂȘncia da unidade de atenção primĂĄria Ă saĂșde SebastiĂŁo Amorim II / Combating Aedes Aegypti and epidemiological investigation of dengue in the area of coverage of the primary health care unit SebastiĂŁo Amorim II
Dengue, Zika e Chikungunya sĂŁo doenças virais que tĂȘm se tornado um grande problema de saĂșde pĂșblica no Brasil. Segundo o MinistĂ©rio da Defesa (2015), 80% dos focos de criadores do mosquito encontram-se no interior e ao redor das residĂȘncias. De acordo com os registros no Sistema de Informação de Agravos de Notificação, em 2012 notificou-se 77 casos em Patos de Minas, hoje este nĂșmero atĂ© o mĂȘs de maio de 2016 jĂĄ se encontra em torno de 233 casos. Dada a gravidade da situação, este trabalho objetivou a busca ativa de focos de proliferação e medidas de conscientização da população em especial da Unidade BĂĄsica de SaĂșde SebastiĂŁo Amorim II no intuito de reduzir a incidĂȘncia do nĂșmero de casos e direcionar o problema para os ĂłrgĂŁos pĂșblicos responsĂĄveis com embasamento teĂłrico e prĂĄtico.
Measuring the strength of interaction between the Ebola fusion peptide and lipid rafts: implications for membrane fusion and virus infection.
The Ebola fusion peptide (EBOââ) is a hydrophobic domain that belongs to the GP2 membrane fusion protein of the Ebola virus. It adopts a helical structure in the presence of mimetic membranes that is stabilized by the presence of an aromatic-aromatic interaction established by Trp8 and Phe12. In spite of its infectious cycle becoming better understood recently, several steps still remain unclear, a lacuna that makes it difficult to develop strategies to block infection. In order to gain insight into the mechanism of membrane fusion, we probed the structure, function and energetics of EBOââ and its mutant W8A, in the absence or presence of different lipid membranes, including isolated domain-resistant membranes (DRM), a good experimental model for lipid rafts. The depletion of cholesterol from living mammalian cells reduced the ability of EBOââ to induce lipid mixing. On the other hand, EBOââ was structurally sensitive to interaction with lipid rafts (DRMs), but the same was not observed for W8A mutant. In agreement with these data, W8A showed a poor ability to promote membrane aggregation in comparison to EBOââ. Single molecule AFM experiments showed a high affinity force pattern for the interaction of EBOââ and DRM, which seems to be a complex energetic event as observed by the calorimetric profile. Our study is the first to show a strong correlation between the initial step of Ebola virus infection and cholesterol, thus providing a rationale for Ebola virus proteins being co-localized with lipid-raft domains. In all, the results show how small fusion peptide sequences have evolved to adopt highly specific and strong interactions with membrane domains. Such features suggest these processes are excellent targets for therapeutic and vaccine approaches to viral diseases
Measuring the Strength of Interaction between the Ebola Fusion Peptide and Lipid Rafts: Implications for Membrane Fusion and Virus Infection
The Ebola fusion peptide (EBO16) is a hydrophobic domain that belongs to the GP2 membrane fusion protein of the Ebola virus. It adopts a helical structure in the presence of mimetic membranes that is stabilized by the presence of an aromaticaromatic interaction established by Trp8 and Phe12. In spite of its infectious cycle becoming better understood recently, several steps still remain unclear, a lacuna that makes it difficult to develop strategies to block infection. In order to gain insight into the mechanism of membrane fusion, we probed the structure, function and energetics of EBO16 and its mutant W8A, in the absence or presence of different lipid membranes, including isolated domain-resistant membranes (DRM), a good experimental model for lipid rafts. The depletion of cholesterol from living mammalian cells reduced the ability of EBO16 to induce lipid mixing. On the other hand, EBO16 was structurally sensitive to interaction with lipid rafts (DRMs), but the same was not observed for W8A mutant. In agreement with these data, W8A showed a poor ability to promote membrane aggregation in comparison to EBO16. Single molecule AFM experiments showed a high affinity force pattern for the interaction of EBO16 and DRM, which seems to be a complex energetic event as observed by the calorimetric profile. Our study is the first to show a strong correlation between the initial step of Ebola virus infection and cholesterol, thus providin
Measuring the strength of interaction between the ebola fusion peptide and lipid rafts: implications for membrane fusion and virus infection
9 p. : il., tab.The Ebola fusion peptide (EBO16) is a hydrophobic domain that belongs to the GP2 membrane fusion protein of the Ebola
virus. It adopts a helical structure in the presence of mimetic membranes that is stabilized by the presence of an aromaticaromatic
interaction established by Trp8 and Phe12. In spite of its infectious cycle becoming better understood recently,
several steps still remain unclear, a lacuna that makes it difficult to develop strategies to block infection. In order to gain
insight into the mechanism of membrane fusion, we probed the structure, function and energetics of EBO16 and its mutant
W8A, in the absence or presence of different lipid membranes, including isolated domain-resistant membranes (DRM), a
good experimental model for lipid rafts. The depletion of cholesterol from living mammalian cells reduced the ability of
EBO16 to induce lipid mixing. On the other hand, EBO16 was structurally sensitive to interaction with lipid rafts (DRMs), but
the same was not observed for W8A mutant. In agreement with these data, W8A showed a poor ability to promote
membrane aggregation in comparison to EBO16. Single molecule AFM experiments showed a high affinity force pattern for
the interaction of EBO16 and DRM, which seems to be a complex energetic event as observed by the calorimetric profile. Our
study is the first to show a strong correlation between the initial step of Ebola virus infection and cholesterol, thus providing
a rationale for Ebola virus proteins being co-localized with lipid-raft domains. In all, the results show how small fusion
peptide sequences have evolved to adopt highly specific and strong interactions with membrane domains. Such features
suggest these processes are excellent targets for therapeutic and vaccine approaches to viral diseases
Dynamic light scattering of vesicles incubated with Ebola fusion peptide.
<p>(A) PC LUVs, (B) PCâ¶PEâ¶PIâ¶Cho LUVs, (C) PCâ¶PEâ¶SPMâ¶Cho LUVs, (D) lipid rafts from BHK-21 cells and (E) lipid rafts from Vero cells. All experiments were done in phosphate buffer pH 7 at 37°C. The peptide concentration was 100 ”M, and the liposome concentration was 1 mM.</p
Transparent thermally stable poly (etherimide) film as flexible substrate for OLEDs
5 p. : il.In this work, ITO thin films were deposited onto poly(etherimide) (PEI) substrates at room temperature
using r.f. magnetron sputtering and successively they were annealed in the 423â523 K (150â250 °C)
temperature range. PEI/ITO substrates were structurally, optically and electrically characterized in order to
verify the quality of the deposited ITO films and the PEI thermal stability during the ITO annealing process. A
transmittance of about 80% was measured in the visible range. The best electrical properties achieved were:
3.04Ă10â4 Ω cm, 12.07Ă1021cm2/V.s, 16.8 Ă 1021 cmâ3, for resistivity, carrier concentration and mobility,
respectively. Small molecule Flexible Organic Light Emitting Diodes (FOLED) were then fabricated and
characterized onto ITO functionalized PEI substrates. These preliminary results show clearly that PEI can be
successfully used as substrate in flexible optoelectronic devices either operating in high temperature or
when the process needs high temperatures
Binding of wtEBO<sub>16</sub> and W8A to lipid membranes by isothermal titration calorimetry.
<p>Each peak corresponds to a 5 ”L injection of vesicles into the sample cell containing a 100 ”M solution of wtEBO<sub>16</sub> (a) or W8A (b) peptide. (A) PC LUVs, (C) PCâ¶PEâ¶PIâ¶Cho LUVs (2â¶1â¶0.5â¶1), (E) PCâ¶PEâ¶SPMâ¶Cho LUVs (1â¶1â¶1â¶1.5) LUVs, (G) lipid rafts from BHK-21 cells and (I) lipid rafts from VERO cells. (B), (D), (F), (H) and (J) are enlarged views of selected heat peak of titration experiments shown in (A, b), (C, b), (E, b), (G, b) and (I, b) curves, respectively. All measurements were conducted at 37°C in phosphate buffer pH 7. The peaks were obtained after subtraction of the heat of dilution of the vesicles into buffer from the raw data obtained with the peptides.</p
Peptide membrane interaction.
<p>(A) Living Vero cells were incubated with wtEBO<sub>16</sub> at 25 (circles) or 37°C (square). Membrane mixing was followed by the decrease in the pyrene excimer/monomer fluorescence ratio for 30 min. (B) Living Vero cells in the absence (square) or in the presence (circle) of MÎČCD were incubated with wtEBO<sub>16</sub> at 37°C. Membrane mixing was followed by the decrease in the pyrene excimer/monomer ratio for 30 min. The peptide concentration was 100 ”M in all experiments. The MÎČCD concentration was 20 mM. The percentage of lipid mixing was obtained by the relation described in Freitas et al <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0015756#pone.0015756-Freitas1" target="_blank">[12]</a>.</p
Schematic view of Ebola virus entry and fusion promoted by the fusion domain (EBO<sub>16</sub>).
<p>The interaction between Trp8 and Phe12 is emphasized with the tridimensional structure of EBO<sub>16</sub> immersed in the lipid membrane (from PDB entry 2RLJ, <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0015756#pone.0015756-Freitas1" target="_blank">[12]</a>).</p
Effect of MÎČCD on cell viability.
<p>(A) Cholesterol depletion. Cells were pre-treated with MÎČCD for 30 min at 37°C, and cholesterol content was quantified as described in Experimental Procedures. (B) Cell viability. Cells were incubated with MÎČCD for 30 min at 37°C. Then MTT reagent was added and incubated for 4 h. The cells were incubated overnight with the solubilization buffer. Absorbance was measured at 570 nm. The bars represent BHK-21, VERO and C636, respectively from left to right.</p