2,547 research outputs found

    Estratifica??o horizontal de insetos fit?fagos, inimigos naturais e compostos qu?micos foliares em Platycyamus regnellii Benth. (Fabaceae) em ?rea degradada

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    ?rea de concentra??o: Produ??o Vegetal.Platycyamus regnellii Benth. (Fabaceae), ? uma esp?cie nativa do Brasil que se distribui em diversos estados brasileiros, adaptando-se ?s condi??es da Bahia, Minas Gerais, Esp?rito Santo, S?o Paulo e Goi?s, sobretudo na floresta semidec?dua de altitude. Apresenta alta toler?ncia a insola??o direta e r?pido crescimento podendo atingir at? 30 metros de altura, caracter?sticas comuns em esp?cies de in?cio de sucess?o florestal. Conhecida como pau-pereira, ? considerada uma planta dec?dua heli?fita, seletiva xer?fita, caracter?stica de terrenos pedregosos e acidentados da floresta semidec?dua de altitude. Muito utilizada em recupera??o de ?reas degradadas, al?m de sua madeira ser aproveitada na constru??o civil e marcenaria em geral. Utiliza-se tamb?m dessa esp?cie para fins ornamentais. Os objetivos foram avaliar os ?ndices ecol?gicos de insetos fit?fagos e inimigos naturais ao longo da estratifica??o horizontal (norte, sul, leste e oeste) e os compostos qu?micos foliares em P. regnellii durante 24 meses em uma ?rea degradada em processo de recupera??o. Os ?ndices ecol?gicos analisados foram domin?ncia-K e biodiversidade e foram observados os valores de riqueza e abund?ncia das esp?cies. Os n?meros de insetos fit?fagos e inimigos naturais foram contabilizados, quinzenalmente, em 48 ?rvores da esp?cie durante o per?odo experimental. A contagem foi realizada por visualiza??o direta, nas faces foliares (adaxial e abaxial)/folha nos galhos posicionados nas faces norte, sul, leste e oeste, totalizando 12 folhas por parte do dossel/avalia??o. Foram realizadas an?lises cromatogr?ficas para os compostos qu?micos foliares de maneira que, uma folha expandida de cada parte do eixo vertical da copa (apical, m?dio e basal) e nos eixos cardinais (norte, sul, leste e oeste), foram coletadas e encaminhada ao laborat?rio para respectivas avalia??es. Para a identifica??o dos compostos qu?micos foliares foi empregada a t?cnica de cromatografia em fase gasosa acoplada ? espectrometria de massa (CG-EM). No total, foram encontradas 37 esp?cies, distribu?dos em vinte e quatro fam?lias e oito ordens. Foram observados nas folhas dos galhos voltadas para as faces leste, norte e norte da copa de P. regnellii, as maiores abund?ncias, riqueza de esp?cies e ?ndices de biodiversidade de insetos fit?fagos, respectivamente. Os insetos herb?voros mais abundantes e com maiores domin?ncias-K em folhas das faces norte, sul, leste e oeste de P. regnellii foram Aleyrodidae (Hemiptera), Phenacoccus sp. (Pseudococcidae), Phenacoccus sp. e Aleyrodidae, respectivamente. J? para os inimigos naturais, observaram-se maiores valores de abund?ncia, riqueza de esp?cies e ?ndice de biodiversidade nas folhas dos galhos voltadas para as faces norte, norte e oeste, respectivamente, nessa planta. Os inimigos naturais mais abundantes e com maiores domin?ncia-K foram Araneidae (Araneae), Dolichopodidae (Diptera), Leucauge sp. (Tetragnathidae) e Dolichopodidae. Foram observados 38 picos de compostos qu?micos foliares em plantas de P. regnellii. Pentacosano foi o composto que apresentou maior corrente de ?ons (CI) nas folhas voltadas para a face norte, seguido por oeste do que nas faces sul e leste e aspidofilina na face norte, seguido por sul e oeste do que na face leste das amostras coletadas nessa planta. Os compostos qu?micos foliares que apresentaram maiores correntes de ?on (CI) foram lupeol, esqualeno e nonacosano e os compostos mais observados foram 1-etenil-1-metil-2-(1-metiletenil)-4-(1-metiletilideno)-cicloexano; 4,8,12,16-Tetrametileptadecan-4-olideo; fitol; nonacosano; 2-pentadecano, 6,10,14-trimetil; 1-metil-5-metileno-8-(1-metiletil)-ciclodeca-1,6-dieno, [s-(E,E)]-; e 2(4H)-Benzofuranona, 5,6,7,7a-tetrahydro-4,4,7a-trimetil. A concentra??o media e frequ?ncia de CI dos compostos n?o diferiram (P > 0,05) entre as faces norte (42,33 ? 19,25 e 46,49 ? 7,18) e as demais (22,97 ? 1,77 e 41,80 ? 1,91) na esp?cie P. regnellii. A maior concentra??o de CI dos compostos e a maior frequ?ncia destes nas folhas dos galhos voltados para a face norte das plantas pode ser devido a resposta da planta ao estresse ambiental como alta radia??o solar, velocidade do vento, altas temperaturas, entre outros. Conclui-se que, os insetos do g?nero Phenacoccus sp. e Aleyrodidae, t?m maior possibilidade de se tornarem pragas em P. regnellii, dentre os inimigos naturais, destacaram-se as aranhas. Os compostos qu?micos foliares fitol, esqualeno e 4,8,12,16-Tetrametilheptadecan-4-olideo podem agir como cairom?nios para os insetos mastigadores e seus inimigos naturais e cicloexano, 11-etenil-1-metil-2-(1-metiletenil)-4-(1-metiletilideno)-cicloexano como alom?nio.Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico (CNPq)Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES)Funda??o de Amparo ? Pesquisa do estado de Minas Gerais (FAPEMIG)Disserta??o (Mestrado) ? Programa de P?s-Gradua??o em Produ??o Vegetal, Universidade Federal dos Vales do Jequitinhonha e Mucuri, 2018.Platycyamus regnellii Benth. (Fabaceae) is a native species of Brazil that is distributed in several Brazilian states, adapting to the conditions of Bahia, Minas Gerais, Esp?rito Santo, S?o Paulo and Goi?s, especially in the semideciduous forest of altitude. It presents high tolerance to direct sunlight and rapid growth, reaching up to 30 meters in height, characteristics common in early forest succession species. Known as pau-pereira, it is considered a deciduous heliophyte, selective xerophyte, characteristic of rocky and rugged terrains of the semi-deciduous forest of altitude. It is very used in recovery of degraded areas, in addition to its wood being used in civil construction and general woodworking. It is also used for ornamental purposes. The objectives were to evaluate the ecological indexes of phytophagous insects and natural enemies along the horizontal stratification (north, south, east and west) and foliar chemical compounds in P. regnellii for 24 months in a degraded area in recovery process. The ecological indexes analyzed were K-dominance and biodiversity and the richness and abundance values of the species were observed. The numbers of phytophagous insects and natural enemies were counted every two weeks in 48 trees of the species during the experimental period. The counting was done by direct visualization on the leaf faces (adaxial and abaxial)/leaf on the branches positioned on the faces north, south, east and west, totaling 12 leaves per part of the canopy/evaluation. Chromatographic analyzes were performed for the foliar chemical compounds so that an expanded leaf of each part of the vertical axis of the canopy (apical, middle and basal) and the cardinal axes (north, south, east and west) were collected and sent to the laboratory for their evaluations. For the identification of foliar chemical compounds the gas chromatography coupled to mass spectrometry (GC-MS) technique was used. In total, 37 species were found, distributed in twenty-four families and eight orders. The highest abundances, species richness and biodiversity indexes of phytophagous insects were observed on the leaves of the branches facing the east, north and north faces of the P. regnellii canopy, respectively. The most abundant herbivorous insects with higher K-dominance on leaves of the north, south, east and west faces of P. regnellii were Aleyrodidae (Hemiptera), Phenacoccus sp. (Pseudococcidae), Phenacoccus sp. and Aleyrodidae, respectively. For the natural enemies, we observed higher values of abundance, species richness and biodiversity index in the leaves of the branches facing north, north and west faces, respectively, in this plant. For the natural enemies, we observed higher values of abundance, species richness and biodiversity index in the leaves of the branches facing north, north and west faces, respectively, in this plant. The most abundant natural enemies with greater K-dominance were Araneidae (Araneae), Dolichopodidae (Diptera), Leucauge sp. (Tetragnathidae) and Dolichopodidae. It was observed 38 peaks of foliar chemical compounds in P. regnellii plants. Pentacosano was the compound that presented higher ions current (CI) in the leaves facing the north face, followed by the west than in the south and east faces and aspidofilina in the north face, followed by the south and west than in the eastern face of the collected samples in this plant. The foliar chemical compounds with the highest ions (IC) currents were lupeol, squalene and nonacosane and the most observed compounds were 1-ethenyl-1-methyl-2- (1-methylethenyl) -4- (1-methylethylidene) -cyclohexane ; 4,8,12,16-Tetramethyleptadecan-4-olide; phytol; nonacosane; 2-pentadecane, 6,10,14-trimethyl; 1-methyl-5-methylene-8- (1-methylethyl) -cyclodeca-1,6-diene, [s- (E, E)] -; and 2 (4H) -Benzofuranone, 5,6,7,7a-tetrahydro-4,4,7a-trimethyl. The concentration and average frequency IC of the compounds did not differ (P> 0.05) between the north faces (? 42.33 19.25 ? 7.18 and 46.49) and the other (22.97 ? 1.77 and 41.80 ? 1.91) in P. regnellii specie. The higher IC concentration of the compounds and their higher frequency in the leaves of the branches facing the north face of the plants may be due to the plant response to environmental stress such as high solar radiation, wind speed, high temperatures, among others. It is concluded that, insects of the genus Phenacoccus sp. and Aleyrodidae, are more likely to become pests in P. regnellii, among the natural enemies, the spiders stand out. The chemical compounds phytol, squalene and 4,8,12,16-Tetramethylheptadecan-4-olide can act as kairomone for chewing insects and their natural enemies and cyclohexane, 1-ethenyl-1-methyl-2- (1-methylethenyl ) -4- (1-methylethylidene) as an allomone

    Self-interaction of human Pex11pβ during peroxisomal growth and division.

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    Journal ArticleResearch Support, Non-U.S. Gov'tCopyright: © 2013 Bonekamp et al.Pex11 proteins are involved in membrane elongation and division processes associated with the multiplication of peroxisomes. Human Pex11pβ has recently been linked to a new disorder affecting peroxisome morphology and dynamics. Here, we have analyzed the exact membrane topology of Pex11pβ. Studies with an epitope-specific antibody and protease protection assays show that Pex11pβ is an integral membrane protein with two transmembrane domains flanking an internal region exposed to the peroxisomal matrix and N- and C-termini facing the cytosol. A glycine-rich internal region within Pex11pβ is dispensable for peroxisome membrane elongation and division. However, we demonstrate that an amphipathic helix (Helix 2) within the first N-terminal 40 amino acids is crucial for membrane elongation and self-interaction of Pex11pβ. Interestingly, we find that Pex11pβ self-interaction strongly depends on the detergent used for solubilization. We also show that N-terminal cysteines are not essential for membrane elongation, and that putative N-terminal phosphorylation sites are dispensable for Pex11pβ function. We propose that self-interaction of Pex11pβ regulates its membrane deforming activity in conjunction with membrane lipids.Portuguese Foundation for Science and Technology (FCT)FEDERCRUP/DAA

    The Cytotoxic T Lymphocyte Antigen-4+49A/G Single Nucleotide Polymorphism Association With Visceral Leishmaniasis

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    Background: Several lines of evidence approve that innate and adaptive immunity play key roles in the defense against visceral leishmaniasis (VL). The polymorphism within the cytotoxic T lymphocyte antigen 4 (CTLA-4) gene alters its expression. Objectives: The main aim of this study was to evaluate the polymorphism within the +49 position of the CTLA-4 gene of Iranian patients with VL in comparison with healthy controls. Materials and Methods: In this cross-sectional study, 88 patients with clinical presentations of VL, who were seropositive for Leishmania (group 1), 86 patients without clinical presentations but seropositive (group 2), and 115 healthy controls (group 3) were assessed with respect to the CTLA-4 +49A/G polymorphism, using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). The anti-Leishmania antibody titration was evaluated using an immunofluorescence method. Results: Our results indicated that both CTLA-4 +49A/G polymorphisms were significantly associated with VL. Conclusions: According to the results, the polymorphisms within the +49 position of CTLA-4 can be associated with VL and may be considered as risk factors for the disease

    RNA polymerase II stalling promotes nucleosome occlusion and pTEFb recruitment to drive immortalization by Epstein-Barr virus

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    Epstein-Barr virus (EBV) immortalizes resting B-cells and is a key etiologic agent in the development of numerous cancers. The essential EBV-encoded protein EBNA 2 activates the viral C promoter (Cp) producing a message of ~120 kb that is differentially spliced to encode all EBNAs required for immortalization. We have previously shown that EBNA 2-activated transcription is dependent on the activity of the RNA polymerase II (pol II) C-terminal domain (CTD) kinase pTEFb (CDK9/cyclin T1). We now demonstrate that Cp, in contrast to two shorter EBNA 2-activated viral genes (LMP 1 and 2A), displays high levels of promoter-proximally stalled pol II despite being constitutively active. Consistent with pol II stalling, we detect considerable pausing complex (NELF/DSIF) association with Cp. Significantly, we observe substantial Cp-specific pTEFb recruitment that stimulates high-level pol II CTD serine 2 phosphorylation at distal regions (up to +75 kb), promoting elongation. We reveal that Cp-specific pol II accumulation is directed by DNA sequences unfavourable for nucleosome assembly that increase TBP access and pol II recruitment. Stalled pol II then maintains Cp nucleosome depletion. Our data indicate that pTEFb is recruited to Cp by the bromodomain protein Brd4, with polymerase stalling facilitating stable association of pTEFb. The Brd4 inhibitor JQ1 and the pTEFb inhibitors DRB and Flavopiridol significantly reduce Cp, but not LMP1 transcript production indicating that Brd4 and pTEFb are required for Cp transcription. Taken together our data indicate that pol II stalling at Cp promotes transcription of essential immortalizing genes during EBV infection by (i) preventing promoter-proximal nucleosome assembly and ii) necessitating the recruitment of pTEFb thereby maintaining serine 2 CTD phosphorylation at distal regions

    Cytokine Production but Lack of Proliferation in Peripheral Blood Mononuclear Cells from Chronic Chagas' Disease Cardiomyopathy Patients in Response to T. cruzi Ribosomal P Proteins

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    Background:Trypanosoma cruzi ribosomal P proteins, P2β and P0, induce high levels of antibodies in patients with chronic Chagas' disease Cardiomyopathy (CCC). It is well known that these antibodies alter the beating rate of cardiomyocytes and provoke apoptosis by their interaction with β1-adrenergic and M2-muscarinic cardiac receptors. Based on these findings, we decided to study the cellular immune response to these proteins in CCC patients compared to non-infected individuals.Methodology/Principal findings:We evaluated proliferation, presence of surface activation markers and cytokine production in peripheral blood mononuclear cells (PBMC) stimulated with P2β, the C-terminal portion of P0 (CP0) proteins and T. cruzi lysate from CCC patients predominantly infected with TcVI lineage. PBMC from CCC patients cultured with P2β or CP0 proteins, failed to proliferate and express CD25 and HLA-DR on T cell populations. However, multiplex cytokine assays showed that these antigens triggered higher secretion of IL-10, TNF-α and GM-CSF by PBMC as well as both CD4+ and CD8+ T cells subsets of CCC subjects. Upon T. cruzi lysate stimulation, PBMC from CCC patients not only proliferated but also became activated within the context of Th1 response. Interestingly, T. cruzi lysate was also able to induce the secretion of GM-CSF by CD4+ or CD8+ T cells.Conclusions/Significance:Our results showed that although the lack of PBMC proliferation in CCC patients in response to ribosomal P proteins, the detection of IL-10, TNF-α and GM-CSF suggests that specific T cells could have both immunoregulatory and pro-inflammatory potential, which might modulate the immune response in Chagas' disease. Furthermore, it was possible to demonstrate for the first time that GM-CSF was produced by PBMC of CCC patients in response not only to recombinant ribosomal P proteins but also to parasite lysate, suggesting the value of this cytokine to evaluate T cells responses in T. cruzi infection.Fil: Longhi, Silvia Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones en Ingeniería Genética y Biología Molecular "Dr. Héctor N. Torres"; Argentina. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica; ArgentinaFil: Atienza, Augusto. Gobierno de la Ciudad de Buenos Aires. Hospital General de Agudos "Ramos Mejía"; ArgentinaFil: Perez Prados, Graciela. Gobierno de la Ciudad de Buenos Aires. Hospital General de Agudos "Juan A. Fernández"; ArgentinaFil: Buying, Alcinette. Torrey Pines Institute for Molecular Studies; Estados UnidosFil: Balouz, Virginia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Biotecnológicas. Universidad Nacional de San Martín. Instituto de Investigaciones Biotecnológicas; ArgentinaFil: Buscaglia, Carlos Andres. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Biotecnológicas. Universidad Nacional de San Martín. Instituto de Investigaciones Biotecnológicas; ArgentinaFil: Santos, Radleigh. Torrey Pines Institute for Molecular Studies; Estados UnidosFil: Tasso, Laura Mónica. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones en Ingeniería Genética y Biología Molecular "Dr. Héctor N. Torres"; ArgentinaFil: Bonato, Ricardo. Gobierno de la Ciudad de Buenos Aires. Hospital General de Agudos "Ramos Mejía"; ArgentinaFil: Chiale, Pablo. Gobierno de la Ciudad de Buenos Aires. Hospital General de Agudos "Ramos Mejía"; ArgentinaFil: Pinilla, Clemencia. Torrey Pines Institute for Molecular Studies; Estados UnidosFil: Judkowski, Valeria A.. Torrey Pines Institute for Molecular Studies; Estados UnidosFil: Gomez, Karina Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones en Ingeniería Genética y Biología Molecular "Dr. Héctor N. Torres"; Argentina. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica; Argentin

    Modelling the Health and Economic Impacts of Population-Wide Testing, Contact Tracing and Isolation (PTTI) Strategies for COVID-19 in the UK

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    Background: The COVID-19 epidemic in the UK has resulted in over 280,000 reported cases and over 40,000 deaths as of 5th June 2020. In the context of a slower increase in reported cases and deaths associated with COVID-19 over the last few weeks compared to earlier in the epidemic, the UK is starting to relax the physical restrictions (‘lockdown’) that have been imposed since 23 March 2020. This has been accompanied by the announcement of a strategy to test people for infection, trace contacts of those tested positive, and isolate positive diagnoses. While such policies are expected to be impactful, there is no conclusive evidence of which approach to this is likely to achieve the most appropriate balance between benefits and costs. This study combines mathematical and economic modelling to estimate the impact, costs, feasibility, and health and economic effects of different strategies. / Methods: We provide detailed description, impact, costing, and feasibility assessment of population-scale testing, tracing, and isolation strategies (PTTI). We estimate the impact of different PTTI strategies with a deterministic mathematical model for SARS-CoV-2 transmission that accurately captures tracing and isolation of contacts of individuals exposed, infectious, and diagnosed with the virus. We combine this with an economic model to project the mortality, intensive care, hospital, and non-hospital case outcomes, costs to the UK National Health Service, reduction in GDP, and intervention costs of each strategy. Model parameters are derived from publicly available data, and the model is calibrated to reported deaths associated with COVID-19. We modelled 31 scenarios in total (Panel 2). The first 18 comprised nine with ‘triggers’ (labelled with the -Trig suffix) for subsequent lockdown periods (>40,000 new infections per day) and lockdown releases (<10,000 new infections per day), and nine corresponding scenarios without triggers, namely: no large-scale PTTI (scenario 1); scale-up of PTTI to testing the whole population every week, with May–July 2020 lockdown release (scenario 2b), or delayed lockdown release until scale-up complete on 31 August 2020 (scenario 2a); these two scenarios with mandatory use of face coverings (scenarios 3a and 3b); and scenarios 2a, 2b, 3a, 3b replacing untargeted PTTI with testing of symptomatic people only (scenarios 4a, 4b, 4c, 4d). The final 13 scenarios looked at: whole population weekly testing to suppress the epidemic with lower tracing success (scenarios 3b-Trig00, 3b-Trig10, 3b-Trig20, 3b-Trig30) and switched to targeted testing after two months when it may suppress the epidemic (scenarios 3b-Trig00-2mo and 3b-Trig30-2mo), and targeted testing with lower tracing success (scenarios 4d-Trig10, 4dTrig20, 4d-Trig30, 4d-Trig40, 4d-Trig50, 4d-Trig60, 4d-Trig70). / Findings: Given that physical distancing measures have already been relaxed in the UK, scenario 4d-Trig (targeted testing of symptomatic people only, with a mandatory face coverings policy and subsequent lockdown triggered to enable PTTI to suppress the epidemic), is a strategy that will result in the fewest deaths (~52,000) and has the lowest intervention costs (~£8bn). The additional lockdown results in total reduction in GDP of ~£503bn, less than half the cost to the economy of subsequent lockdowns triggered in a scenario without PTTI (scenario 1-Trig, ~£1180bn reduction in GDP, ~105,000 deaths). In summer months, with lower cold and flu prevalence, approximately 75,000 symptomatic people per day need to be tested for this strategy to work, assuming 64% of their contacts are effectively traced (~80% traced with 80% success) within the infectious period (most within the first two days and nearly all by seven days) and all are isolated – including those without any symptoms – for 14 days. Untargeted testing of everyone every week, if it were feasible, may work without tracing, but at a higher cost (scenario 3b-Trig00). This cost could be reduced by switching to targeted testing after the epidemic is suppressed (scenario 3b-Trig30-2mo), though we note the epidemic could be suppressed with targeted testing itself providing tracing and isolation has at least a 32% success rate (scenario 4dTrig40). / Interpretation: PTTI strategies to suppress the COVID-19 epidemic within the context of a relaxation of lockdown will necessitate subsequent lockdowns to keep the epidemic suppressed during PTTI scale-up. Targeted testing of symptomatic people only can suppress the epidemic if accompanied by mandated use of face coverings. The feasibility of PTTI depends on sufficient capacity, capabilities, infrastructure and integrated systems to deliver it. The political and public acceptability of alternative scenarios for subsequent lockdowns needs to take account of crucial implications for employment, personal and national debt, education, population mental health and non-COVID-19 disease. Our model is able to incorporate additional scenarios as the situation evolves
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