230 research outputs found

    Avaliação de genótipos de feijoeiro comum, na safra da seca, no Estado do Espírito Santo.

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    Este trabalho teve como objetivo avaliar a produtividade de 21 genótipos de feijoeiro comum, na safra da seca, em quatro municípios do Estado do Espírito Santo

    POLRMT regulates the switch between replication primer formation and gene expression of mammalian mtDNA

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    Mitochondria are vital in providing cellular energy via their oxidative phosphorylation system, which requires the coordinated expression of genes encoded by both the nuclear and mitochondrial genomes (mtDNA). Transcription of the circular mammalian mtDNA depends on a single mitochondrial RNA polymerase (POLRMT). Although the transcription initiation process is well understood, it is debated whether POLRMT also serves as the primase for the initiation of mtDNA replication. In the nucleus, the RNA polymerases needed for gene expression have no such role. Conditional knockout of Polrmt in the heart results in severe mitochondrial dysfunction causing dilated cardiomyopathy in young mice. We further studied the molecular consequences of different expression levels of POLRMT and found that POLRMT is essential for primer synthesis to initiate mtDNA replication in vivo. Furthermore, transcription initiation for primer formation has priority over gene expression. Surprisingly, mitochondrial transcription factor A (TFAM) exists in an mtDNA-free pool in the Polrmt knockout mice. TFAM levels remain unchanged despite strong mtDNA depletion, and TFAM is thus protected from degradation of the AAA(+) Lon protease in the absence of POLRMT. Last, we report that mitochondrial transcription elongation factor may compensate for a partial depletion of POLRMT in heterozygous Polrmt knockout mice, indicating a direct regulatory role of this factor in transcription. In conclusion, we present in vivo evidence that POLRMT has a key regulatory role in the replication of mammalian mtDNA and is part of a transcriptional mechanism that provides a switch between primer formation for mtDNA replication and mitochondrial gene expression

    Identifying SARS-CoV-2 antiviral compounds by screening for small molecule inhibitors of nsp13 helicase

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    The coronavirus disease 2019 (COVID-19) pandemic, which is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is a global public health challenge. While the efficacy of vaccines against emerging and future virus variants remains unclear, there is a need for therapeutics. Repurposing existing drugs represents a promising and potentially rapid opportunity to find novel antivirals against SARS-CoV-2. The virus encodes at least nine enzymatic activities that are potential drug targets. Here, we have expressed, purified and developed enzymatic assays for SARS-CoV-2 nsp13 helicase, a viral replication protein that is essential for the coronavirus life cycle. We screened a custom chemical library of over 5000 previously characterized pharmaceuticals for nsp13 inhibitors using a fluorescence resonance energy transfer-based high-throughput screening approach. From this, we have identified FPA-124 and several suramin-related compounds as novel inhibitors of nsp13 helicase activity in vitro. We describe the efficacy of these drugs using assays we developed to monitor SARS-CoV-2 growth in Vero E6 cells

    Common bean cultivar BRS Ametista with large Carioca grains and disease resistance.

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    BRS Ametista is a common bean cultivar with Carioca grain and yields similar to cultivar Pérola, but with larger grain size, resistance to anthracnose and Fusarium wilt. It is recommended for 18 states in all regions of Brazil and can be planted on over 95% of the area used for common bean in the country

    BRS Estilo - cultivar de feijão carioca com grãos claros, arquitetura ereta e alto potencial produtivo.

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    A BRS Estilo é uma nova cultivar de feijoeiro-comum com grãos carioca, indicada para cultivo em 13 Estados, pertencentes às cinco regiões brasileiras. Apresenta 2.072,3 kg ha-1 de produtividade média, 7,5% de superioridade em relação às testemunhas, grãos claros, alto potencial produtivo (4.011 kg ha-1), arquitetura ereta, tolerância ao acamamento e resistência a antracnose

    BRS Esplendor - cultivar de feijoeiro com grãos pretos, arquitetura ereta e resistência a doenças.

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    A BRS Esplendor é uma cultivar de feijoeiro comum com grãos pretos, indicada para 13 Estados brasileiros. Apresenta 2.112 kg/ha de produtividade média, 8,2% de superioridade em relação às testemunhas, alto potencial produtivo (4.120 kg/ha), arquitetura ereta e resistência a antracnose, murcha de fusarium e crestamento bacteriano comum e tolerância ao acamamento

    BRS Esteio - cultivar de feijoeiro-comum com grãos pretos, alto potencial produtivo e moderada resistência à antracnose.

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    O programa de melhoramento genético do feijoeiro-comum da Embrapa Arroz e Feijão está focado na busca de cultivares com alto potencial produtivo, mais resistentes a doenças e com arquitetura de planta ereta, que possibilitem inclusive a colheita mecanizada direta, para que os agricultores possam ofertar um produto de melhor qualidade ao consumidor e auferir maiores rendimentos com a cultura. A cultivar de feijoeiro-comum com grãos pretos BRS Esteio apresenta ciclo normal, alto potencial produtivo, estabilidade de produção, grãos com excelentes qualidades culinárias e moderada resistência à antracnose.CONAF

    Fluorescent RNA cytosine analogue - an internal probe for detailed structure and dynamics investigations

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    The bright fluorescent cytosine analogue tCO stands out among fluorescent bases due to its virtually unquenched fluorescence emission in duplex DNA. However, like most reported base analogues, it has not been thoroughly characterized in RNA. We here report on the first synthesis and RNA-incorporation of tCO, and characterize its base-mimicking and fluorescence properties in RNA. As in DNA, we find a high quantum yield inside RNA duplexes (<?F> = 0.22) that is virtually unaffected by the neighbouring bases (?F = 0.20-0.25), resulting in an average brightness of 1900 M-1 cm-1. The average fluorescence lifetime in RNA duplexes is 4.3 ns and generally two lifetimes are required to fit the exponential decays. Fluorescence properties in ssRNA are defined by a small increase in average quantum yield (<?F > = 0.24) compared to dsRNA, with a broader distribution (?F = 0.17-0.34) and slightly shorter average lifetimes. Using circular dichroism, we find that the tCO-modified RNA duplexes form regular A-form helices and in UV-melting experiments the stability of the duplexes is only slightly higher than that of the corresponding natural RNA (<?T m> = + 2.3 °C). These properties make tCO a highly interesting fluorescent RNA base analogue for detailed FRET-based structural measurements, as a bright internal label in microscopy, and for fluorescence anisotropy measurements of RNA dynamics

    Mutations in mitochondrial DNA causing tubulointerstitial kidney disease

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    Tubulointerstitial kidney disease is an important cause of progressive renal failure whose aetiology is incompletely understood. We analysed a large pedigree with maternally inherited tubulointerstitial kidney disease and identified a homoplasmic substitution in the control region of the mitochondrial genome (m.547A>T). While mutations in mtDNA coding sequence are a well recognised cause of disease affecting multiple organs, mutations in the control region have never been shown to cause disease. Strikingly, our patients did not have classical features of mitochondrial disease. Patient fibroblasts showed reduced levels of mitochondrial tRNAPhe^{Phe}, tRNALeu1^{Leu1} and reduced mitochondrial protein translation and respiration. Mitochondrial transfer demonstrated mitochondrial transmission of the defect and in vitro assays showed reduced activity of the heavy strand promoter. We also identified further kindreds with the same phenotype carrying a homoplasmic mutation in mitochondrial tRNAPhe^{Phe} (m.616T>C). Thus mutations in mitochondrial DNA can cause maternally inherited renal disease, likely mediated through reduced function of mitochondrial tRNAPhe^{Phe}.This study was supported by a Wellcome Trust Senior Investigator Award to PHM [19710], by the National Institute for Health Research Cambridge and Imperial Biomedical Research Centres, and a Medical Research Council Clinical Training Fellowship awarded to TMC. The core facilities at CIMR were funded by a Wellcome Trust strategic award [100140]. PFC is a Wellcome Trust Senior Fellow in Clinical Science [101876/Z/13/Z] within the Medical Research Council Mitochondrial Biology Unit [MC_UP_1501/2]. CMG was supported by The Swedish Medical Research Council and The Knut and Alice Wallenberg Foundation. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript
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