Avalia??o de plantas forrageiras tropicais sob sombreamentos no outono e inverno

O presente trabalho foi realizado com apoio da Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior - Brasil (CAPES) - C?digo de Financiamento 001.Os sistemas de integra??o lavoura-pecu?ria-floresta, tamb?m conhecidos como agrossilvipastoris, podem contribuir positivamente para os sistemas de produ??o animal e s?o alternativas eficientes de uso da terra na recupera??o de ?reas degradadas. No entanto, a toler?ncia de gram?neas e leguminosas ao sombreamento depende da sua capacidade morfofisiol?gica para se adaptar a determinado n?vel de radia??o, conhecido como plasticidade fenot?pica. O objetivo com este trabalho foi avaliar o comportamento de quatro cultivares de plantas forrageiras tropicais sob diferentes n?veis de sombreamento e manejadas a 95% de intercepta??o luminosa (IL), ao longo do outono e inverno de 2019. Foram realizados quatro experimentos com quatro esp?cies forrageiras tropicais: Brachiaria spp. cv. Mavuno (capim-mavuno), Panicum maximum Jack cv. BRS Zuri (capim-zuri), Panicum maximum cv. BRS Tamani (capim-tamani) e Arachis pintoi cv. Amarillo (amendoim forrageiro). Cada experimento foi realizado em delineamento inteiramente casualizado (DIC), com seis repeti??es, submetidos aos n?veis de sombreamento artificial de 47% com radia??o fotossint?ticamente ativa (RFA) de 353 ?mol m-2s-1, de 64% com RFA de 242 ?mol m-2s-1, 74% com RFA de 172 ?mol m-2s-1 e o tratamento controle com as plantas cultivadas sem sombreamento, com RFA de 668 ?mol m-2s-1. As plantas foram mantidas sob regime de corte ao atingir 95% de IL. Durante o experimento foram realizadas avalia??es morfog?nicas para determina??o das vari?veis-respostas: taxa de aparecimento foliar, filocrono, taxa de alongamento foliar, taxa de senesc?ncia foliar, dura??o de vida da folha, taxa de alongamento do colmo/caule para todas as forrageiras e tamb?m a taxa de alongamento em largura e taxa de alongamento do pec?olo para o amendoim forrageiro. Antes do corte tamb?m foram realizadas as avalia??es estruturais, referentes ao n?mero de folhas vivas por perfilho, comprimento final da folha e do colmo ou caule, altura final das plantas, o ?ndice de ?rea foliar, densidade de perfilhos e o peso m?dio dos perfilhos. Tamb?m foram realizadas an?lises fisiol?gicas referentes aos teores de clorofila a e b, taxa fotossint?tica, condut?ncia estom?tica, taxa transpirat?ria, efici?ncia no uso da ?gua e temperatura da folha. Posteriormente, ap?s o corte foi determinada a composi??o morfol?gica (propor??o de folhas, colmo ou caule, material senescente e infloresc?ncia) e a produ??o de massa seca total de cada esp?cie forrageira sob os diferentes n?veis de sombreamento. Todos os dados foram analisados no programa estat?stico Statistical Analysis System - SAS 9.1. As m?dias das caracter?sticas morfog?nicas, morfofisiol?gicas e produtivas foram submetidas ? an?lise de vari?ncia e posteriormente ? an?lise de regress?o linear e quadr?tica a 5% de probabilidade. O capim-mavuno apresentou adapta??o aos sombreamentos de 47%, 64% e 74% ao longo do outono e inverno, visto que a produ??o de massa seca n?o diminuiu mesmo com a restri??o luminosa imposta pelos n?veis de sombreamentos nas plantas e houve aumentos no ?ndice de ?rea foliar, na propor??o de folhas, no teor de clorofila a e b e na taxa fotossint?tica nos sistemas sombreados. O capim-zuri apresenta alta adapta??o ao sombreamento de 64%, visto que nesta condi??o houve maior produ??o de massa seca, maiores propor??es de folhas e da taxa de aparecimento foliar e aumentos nos teores de clorofila que consequentemente proporcionaram maiores taxas fotossint?ticas sob este n?vel de sombreamento. O capim-tamani apresentou grande toler?ncia aos sombreamentos de 47% e 64%, aumentando a produ??o de massa seca, a taxa fotossint?tica, a clorofila a e b, a taxa de aparecimento foliar, a propor??o de folhas e a rela??o folha/colmo da composi??o morfol?gica, quando comparado as plantas sem sombreamento. Foi verificado tamb?m que o capim-tamani pode ser sombreado em at? 74% sem reduzir a produ??o em compara??o com as plantas que crescem sem sombreamento. O amendoim forrageiro apresentou grande adapta??o ao sombreamento a 47%, aumentando a produ??o de massa seca, a taxa fotossint?tica, a propor??o de folhas e a rela??o folha/ caule quando comparado as plantas sem sombreamento e com sombreamento de 64 e 74%. Com isso o capim-tamani quando comparado com outros capins, apresenta maior adapta??o aos diferentes n?veis de sombreamento durante a esta??o outono e inverno, seguido pelo capim zuri e o capim mavuno. J? a leguminosa amendoim forrageiro durante a esta??o outono e inverno, apresenta toler?ncia a baixos n?veis de sombreamento.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, 2020.The crop-livestock-forest integration systems, also known as agrosilvipastoris, can contribute positively to animal production systems and are efficient alternatives for land use in the recovery of degraded areas. However, the tolerance of grasses and legumes to shading depends on their morphophysiological capacity to adapt to a certain level of radiation, known as phenotypic plasticity. The objective of this work was to evaluate the behavior of four cultivars of tropical forage plants under different levels of shading and managed at 95% light interception (IL), throughout the fall and winter of 2019. Four experiments were carried out with four forage species tropical: Brachiaria spp. cv. Mavuno (mavuno grass), Panicum maximum Jack cv. BRS Zuri (zuri grass), Panicum maximum cv. BRS Tamani (tamani grass) and Arachis pintoi cv. Amarillo (forage peanut). Each experiment was carried out in a completely randomized design (DIC), with six replications, subjected to artificial shading levels of 47% with photosynthetically active radiation (RFA) of 353 ?mol m-2s-1, 64% with RFA of 242 ?mol m- 2s-1, 74% with RFA of 172 ?mol m-2s-1 and the control treatment with plants grown without shading, with RFA of 668 ?mol m-2s-1. The plants were kept under a cutting regime when reaching 95% IL. During the experiment, morphogenic evaluations were performed to determine the response variables: leaf appearance rate, phyllochron, leaf elongation rate, leaf senescence rate, leaf life duration, stem / stem elongation rate for all forages and also the rate of elongation in width and the rate of elongation of the petiole for forage peanut. Before cutting, structural evaluations were also carried out, referring to the number of live leaves per tiller, final length of the leaf and stem or stem, final height of the plants, the leaf area index, tiller density and the average weight of tillers. Physiological analyzes were also carried out regarding the levels of chlorophyll a and b, photosynthetic rate, stomatal conductance, transpiratory rate, water use efficiency and leaf temperature. Subsequently, after cutting, the morphological composition (proportion of leaves, stem or stem, senescent material and inflorescence) and the production of total dry mass of each forage species were determined under the different levels of shading. All data were analyzed using the statistical program Statistical Analysis System - SAS 9.1. The means of the morphogenic, morphophysiological and productive characteristics were subjected to analysis of variance and subsequently to the analysis of linear and quadratic regression at 5% probability. The mavuno grass showed adaptation to the shading of 47%, 64% and 74% throughout autumn and winter, since the production of dry mass did not decrease even with the light restriction imposed by the levels of shading in the plants and there were increases in the index leaf area, leaf proportion, chlorophyll content a and b and photosynthetic rate in shaded systems. Zuri grass has a high adaptation to shading of 64%, since in this condition there was greater production of dry mass, higher proportions of leaves and the rate of leaf appearance and increases in chlorophyll contents which consequently provided higher photosynthetic rates under this level of shading. Tamani grass showed great tolerance to shading of 47% and 64%, increasing dry mass production, photosynthetic rate, chlorophyll a and b, leaf appearance rate, leaf proportion and leaf / stem ratio of the morphological composition, when compared to plants without shading. It was also found that tamani grass can be shaded by up to 74% without reducing production compared to plants that grow without shading. Forage peanuts showed great adaptation to shading at 47%, increasing the dry matter production, the photosynthetic rate, the proportion of leaves and the leaf / stem ratio when compared to plants without shading and with shading of 64 and 74%. As a result, tamani grass, when compared to other grasses, shows greater adaptation to different levels of shade during the autumn and winter season, followed by zuri grass and mavuno grass. The forage peanut legume during the autumn and winter season, tolerates low levels of shading

miR-155 in the progression of lung fibrosis in systemic sclerosis

Background: MicroRNA (miRNA) control key elements of mRNA stability and likely contribute to the dysregulated lung gene expression observed in systemic sclerosis associated interstitial lung disease (SSc-ILD). We analyzed the miRNA gene expression of tissue and cells from patients with SSc-ILD. A chronic lung fibrotic murine model was used. Methods: RNA was isolated from lung tissue of 12 patients with SSc-ILD and 5 controls. High-resolution computed tomography (HRCT) was performed at baseline and 2-3 years after treatment. Lung fibroblasts and peripheral blood mononuclear cells (PBMC) were isolated from healthy controls and patients with SSc-ILD. miRNA and mRNA were analyzed by microarray, quantitative polymerase chain reaction, and/or Nanostring; pathway analysis was performed by DNA Intelligent Analysis (DIANA)-miRPath v2.0 software. Wild-type and miR-155 deficient (miR-155ko) mice were exposed to bleomycin. Results: Lung miRNA microarray data distinguished patients with SSc-ILD from healthy controls with 185 miRNA differentially expressed (q < 0.25). DIANA-miRPath revealed 57 Kyoto Encyclopedia of Genes and Genomes pathways related to the most dysregulated miRNA. miR-155 and miR-143 were strongly correlated with progression of the HRCT score. Lung fibroblasts only mildly expressed miR-155/miR-21 after several stimuli. miR-155 PBMC expression strongly correlated with lung function tests in SSc-ILD. miR-155ko mice developed milder lung fibrosis, survived longer, and weaker lung induction of several genes after bleomycin exposure compared to wild-type mice. Conclusions: miRNA are dysregulated in the lungs and PBMC of patients with SSc-ILD. Based on mRNA-miRNA interaction analysis and pathway tools, miRNA may play a role in the progression of the disease. Our findings suggest that targeting miR-155 might provide a novel therapeutic strategy for SSc-ILD

A review exploring the overarching burden of Zika virus with emphasis on epidemiological case studies from Brazil

This paper explores the main factors for mosquito-borne transmission of the Zika virus by focusing on environmental, anthropogenic, and social risks. A literature review was conducted bringing together related information from this genre of research from peer-reviewed publications. It was observed that environmental conditions, especially precipitation, humidity, and temperature, played a role in the transmission. Furthermore, anthropogenic factors including sanitation, urbanization, and environmental pollution promote the transmission by affecting the mosquito density. In addition, socioeconomic factors such as poverty as well as social inequality and low-quality housing have also an impact since these are social factors that limit access to certain facilities or infrastructure which, in turn, promote transmission when absent (e.g., piped water and screened windows). Finally, the paper presents short-, mid-, and long-term preventative solutions together with future perspectives. This is the first review exploring the effects of anthropogenic aspects on Zika transmission with a special emphasis in Brazil

Comparative study on the use of specific and heterologous microsatellite primers in the stingless bees Melipona rufiventris and M. mondury (Hymenoptera, Apidae)

Due to their high degree of polymorphism, microsatellites are considered useful tools for studying population genetics. Nevertheless, studies of genetic diversity in stingless bees by means of these primers have revealed a low level of polymorphism, possibly the consequence of the heterologous primers used, since in most cases these were not specifically designed for the species under consideration. Herein we compared the number of polymorphic loci and alleles per locus, as well as observed heterozygosity in Melipona rufiventris and M. mondury populations, using specific and heterologous primers. The use of specific primers placed in evidence the greater frequency of polymorphic loci and alleles per locus, besides an expressive increase in observed heterozygosity in M. rufiventris and M. mondury, thereby reinforcing the idea that populational studies should be undertaken by preferably using species-specific microsatellite primers