Mostrando recursos 1 - 20 de 35

  1. Potential Mechanisms Underlying Response to Effects of the Fungicide Pyrimethanil from Gene Expression Profiling inSaccharomyces cerevisiae

    Gil, Fátima N.; Becker, Jörg D.; Viegas, Cristina A.
    Pyrimethanil is a fungicide mostly applied in vineyards. When misused, residue levels detected in grape must or in the environment may be of concern. The present work aimed to analyze mechanisms underlying response to deleterious effects of pyrimethanil in the eukaryotic model Saccharomyces cerevisiae. Pyrimethanil concentration-dependent effects at phenotypic (inhibition of growth) and transcriptomic levels were examined. For transcriptional profiling, analysis focused on two sublethal exposure conditions that inhibited yeast growth by 20% or 50% compared with control cells not exposed to the fungicide. Gene expression modifications increased with the magnitude of growth inhibition, in numbers and fold-change of differentially...

  2. Transcriptional profiling in Saccharomyces cerevisiae relevant for predicting alachlor mechanisms of toxicity

    Gil, Fátima N.; Gonçalves, Alina C.; Jacinto, Maria João; Becker, Jörg D.; Viegas, Cristina A.
    Alachlor has been a commonly applied herbicide and is a substance of ecotoxicological concern. The present study aims to identify molecular biomarkers in the eukaryotic model Saccharomyces cerevisiae that can be used to predict potential cytotoxic effects of alachlor, while providing new mechanistic clues with possible relevance for experimentally less accessible eukaryotes. It focuses on genome-wide expression profiling in a yeast population in response to two exposure scenarios exerting effects from slight to moderate magnitude at phenotypic level. In particular, 100 and 264 genes, respectively, were found as differentially expressed on a 2-h exposure of yeast cells to the lowest...

  3. Identification of differentially expressed genes in the heart precursor cells of the chick embryo

    Bento, Margaret; Correia, Elizabeth; Tavares, Ana T; Becker, Jörg D; Belo, José A
    Genetic evidence has implicated several genes as being critical for heart development. However, the inducers of these genes as well as their targets and pathways they are involved with, remain largely unknown. Previous studies in the avian embryo showed that at HH4 Cerberus (cCer) transcripts are detected in the anterior endomesoderm including the heart precursor cells and later in the left lateral plate mesoderm. We have identified a promoter element of chick cCer able to drive EGFP expression in a population of cells that consistently exit from the anterior primitive streak region, from as early as stage HH3+, and that...

  4. H3K4me3 - dependent epigenetic memory regulates transcriptional reactivation in the oocyte

    Navarro-Costa, P.; Prudêncio, P.; J.D., Becker; R.G., Martinho
    SELECTED ORAL COMMUNICATIONS, SESSION 52: EPIGENETIC PATTERN IN OOCYTE AND EMBRYO, Tuesday 16 June 2015. This article/study appears in: Abstract book of the 31st ESHRE Annual Meeting, Lisbon, Portugal, 14-17 June 2015.

  5. Evolutionarily conserved mechanisms of male germline development in flowering plants and animals

    Pereira, Patrícia A.; Navarro-Costa, Paulo; Martinho, Rui Gonçalo; Becker, Jörg D.
    Sexual reproduction is the main reproductive strategy of the overwhelming majority of eukaryotes. This suggests that the last eukaryotic common ancestor was able to reproduce sexually. Sexual reproduction reflects the ability to perform meiosis, and ultimately generating gametes, which are cells that carry recombined half sets of the parental genome and are able to fertilize. These functions have been allocated to a highly specialized cell lineage: the germline. Given its significant evolutionary conservation, it is to be expected that the germline programme shares common molecular bases across extremely divergent eukaryotic species. In the present review, we aim to identify the...

  6. Heat and water stress induce unique transcriptional signatures of heat-shock proteins and transcription factors in grapevine

    Rocheta, Margarida; Becker, Jörg D.; Coito, João L.; Carvalho, Luísa; Amâncio, Sara
    Grapevine is an extremely important crop worldwide.In southern Europe, post-flowering phases of the growth cycle can occur under high temperatures, excessive light, and drought conditions at soil and/or atmospheric level. In this study, we subjected greenhouse grown grapevine, variety Aragonez, to two individual abiotic stresses, water deficit stress(WDS), and heat stress (HS). The adaptation of plants to stress is a complex response triggered by cascades of molecular net works involved in stress perception, signal transduction, and the expression of specific stress-related genes and metabolites. Approaches such as array-based transcript profiling allow assessing the expression of thousands of genes in control...

  7. Plant Evolution: What Does It Take To Be an Egg?

    Boavida, Leonor C.; Becker, Jörg D.
    The genetic regulation of cell patterning within plant gametophytes remains poorly understood. Now, two new studies in the liverwort Marchantia polymorpha shed light on the conserved function of an RKD transcription factor as a key regulator of egg cell fate in the land plant lineage.

  8. A Transcriptome Atlas of Physcomitrella patens Provides Insights into the Evolution and Development of Land Plants

    Ortiz-Ramírez, Carlos; Hernandez-Coronado, Marcela; Thamm, Anna; Catarino, Bruno; Wang, Mingyi; Dolan, Liam; Feijó, José A.; Becker, Jörg D.
    Post-print version of the article.

  9. HydroxyprolineO-arabinosyltransferase mutants oppositely alter tip growth inArabidopsis thalianaandPhyscomitrella patens

    MacAlister, Cora A.; Ortiz-Ramírez, Carlos; Becker, Jörg D.; Feijó, José A.; Lippman, Zachary B.
    Hydroxyproline O-arabinosyltransferases (HPATs) are members of a small, deeply conserved family of plant-specific glycosyltransferases that add arabinose sugars to diverse proteins including cell wall-associated extensins and small signaling peptides. Recent genetic studies in flowering plants suggest that different HPAT homologs have been co-opted to function in diverse species-specific developmental contexts. However, nothing is known about the roles of HPATs in basal plants. We show that complete loss of HPAT function in Arabidopsis thaliana and the moss Physcomitrella patens results in a shared defect in gametophytic tip cell growth. Arabidopsis hpat1/2/3 triple knockout mutants suffer from a strong male sterility defect...

  10. The Sinorhizobium meliloti EmrR Regulator Is Required for Efficient Colonization of Medicago sativa Root Nodules

    Santos, Mário R.; Marques, Andreia T.; Becker, Jörg D.; Moreira, Leonilde M.
    The nitrogen-fixing bacterium Sinorhizobium meliloti must adapt to diverse conditions encountered during its symbiosis with leguminous plants. We characterized a new symbiotically relevant gene, emrR (SMc03169), whose product belongs to the TetR family of repressors and is divergently transcribed from emrAB genes encoding a putative major facilitator superfamily-type efflux pump. An emrR deletion mutant produced more succinoglycan, displayed increased cell-wall permeability, and exhibited higher tolerance to heat shock. It also showed lower tolerance to acidic conditions, a reduced production of siderophores, and lower motility and biofilm formation. The simultaneous deletion of emrA and emrR genes restored the mentioned traits to...

  11. Transthyretin Proteins Regulate Angiogenesis by Conferring Different Molecular Identities to Endothelial Cells

    Nunes, R. J.; de Oliveira, P.; Lages, A.; Becker, J. D.; Marcelino, P.; Barroso, E.; Perdigoto, R.; Kelly, J. W.; Quintas, A.; Santos, S. C. R.
    Familial amyloidotic polyneuropathy (FAP) has a high prevalence in Portugal, and the most common form of hereditary amyloidosis is caused by an amyloidogenic variant of transthyretin (TTR) with a substitution of methionine for valine at position 30 (V30M). Until now, the available efficient therapy is liver transplantation, when performed in an early phase of the onset of the disease symptoms. However, transplanted FAP patients have a significantly higher incidence of early hepatic artery thrombosis compared with non-FAP transplanted patients. Because FAP was described as an independent risk factor for early hepatic artery thrombosis, more studies to understand the underlying mechanisms...

  12. Plant Genes Related to Gibberellin Biosynthesis and Signaling Are Differentially Regulated during the Early Stages of AM Fungal Interactions

    Ortu, Giuseppe; Balestrini, Raffaella; Pereira, Patrícia A.; Becker, Jörg D.; Küster, Helge; Bonfante, Paola
    Dear Editor, Phytohormones are essential regulators of plant development, but their role in the signaling processes between plants and fungi during arbuscular mycorrhizal (AM) establishment is far from being understood (Ludwig-Müller, 2010). AM colonization leads to extensive effects on host metabolism, as revealed by transcriptome studies of AM plants (Hogekamp et al., 2011). Some genes have been specified as an AM core set, since they are mycorrhizal-responsive, irrespective of the identity of the plant, of the fungus, and of the investigated organ. These data support the idea that, on colonization, plants activate a wide reprogramming of their major regulatory networks and...

  13. Reprogramming of DNA Methylation in Pollen Guides Epigenetic Inheritance via Small RNA

    Calarco, Joseph P.; Borges, Filipe; Donoghue, Mark T.A.; Van Ex, Frédéric; Jullien, Pauline E.; Lopes, Telma; Gardner, Rui; Berger, Frédéric; Feijó, José A.; Becker, Jörg D.; Martienssen, Robert A.
    Epigenetic inheritance is more widespread in plants than in mammals, in part because mammals erase epigenetic information by germline reprogramming. We sequenced the methylome of three haploid cell types from developing pollen: the sperm cell, the vegetative cell, and their precursor, the postmeiotic microspore, and found that unlike in mammals the plant germline retains CG and CHG DNA methylation. However, CHH methylation is lost from retrotransposons in microspores and sperm cells and restored by de novo DNA methyltransferase guided by 24 nt small interfering RNA, both in the vegetative nucleus and in the embryo after fertilization. In the vegetative nucleus,...

  14. Transcriptomic comparison between two Vitis vinifera L. varieties (Trincadeira and Touriga Nacional) in abiotic stress conditions

    Rocheta, Margarida; Coito, João L; Ramos, Miguel J N; Carvalho, Luísa; Becker, Jörg D; Carbonell-Bejerano, Pablo; Amâncio, Sara
    Predicted climate changes announce an increase of extreme environmental conditions including drought and excessive heat and light in classical viticultural regions. Thus, understanding how grapevine responds to these conditions and how different genotypes can adapt, is crucial for informed decisions on accurate viticultural actions. Global transcriptome analyses are useful for this purpose as the response to these abiotic stresses involves the interplay of complex and diverse cascades of physiological, cellular and molecular events. The main goal of the present work was to evaluate the response to diverse imposed abiotic stresses at the transcriptome level and to compare the response of...

  15. Reprogramming of DNA Methylation in Pollen Guides Epigenetic Inheritance via Small RNA

    Calarco, Joseph P.; Borges, Filipe; Donoghue, Mark T.A.; Van Ex, Frédéric; Jullien, Pauline E.; Lopes, Telma; Gardner, Rui; Berger, Frédéric; Feijó, José A.; Becker, Jörg D.; Martienssen, Robert A.
    Epigenetic inheritance is more widespread in plants than in mammals, in part because mammals erase epigenetic information by germline reprogramming. We sequenced the methylome of three haploid cell types from developing pollen: the sperm cell, the vegetative cell, and their precursor, the postmeiotic microspore, and found that unlike in mammals the plant germline retains CG and CHG DNA methylation. However, CHH methylation is lost from retrotransposons in microspores and sperm cells and restored by de novo DNA methyltransferase guided by 24 nt small interfering RNA, both in the vegetative nucleus and in the embryo after fertilization. In the vegetative nucleus,...

  16. Inhibition of glutamine synthetase by phosphinothricin leads to transcriptome reprograming in root nodules of Medicago truncatula

    Seabra, Ana R; Pereira, Patrícia A; Becker, Jörg D; Carvalho, Helena G
    Glutamine synthetase (GS) is a vital enzyme for the assimilation of ammonia into amino acids in higher plants. In legumes, GS plays a crucial role in the assimilation of the ammonium released by nitrogen-fixing bacteria in root nodules, constituting an important metabolic knob controlling the nitrogen (N) assimilatory pathways. To identify new regulators of nodule metabolism, we profiled the transcriptome of Medicago truncatula nodules impaired in N assimilation by specifically inhibiting GS activity using phosphinothricin (PPT). Global transcript expression of nodules collected before and after PPT addition (4, 8, and 24 h) was assessed using Affymetrix M. truncatula GeneChip arrays....

  17. Whole Genome Analysis of Gene Expression Reveals Coordinated Activation of Signaling and Metabolic Pathways during Pollen-Pistil Interactions in Arabidopsis

    Boavida, L. C.; Borges, F.; Becker, J. D.; Feijo, J. A.
    Plant reproduction depends on the concerted activation of many genes to ensure correct communication between pollen and pistil. Here, we queried the whole transcriptome of Arabidopsis (Arabidopsis thaliana) in order to identify genes with specific reproductive functions. We used the Affymetrix ATH1 whole genome array to profile wild-type unpollinated pistils and unfertilized ovules. By comparing the expression profile of pistils at 0.5, 3.5, and 8.0 h after pollination and applying a number of statistical and bioinformatics criteria, we found 1,373 genes differentially regulated during pollen-pistil interactions. Robust clustering analysis grouped these genes in 16 time-course clusters representing distinct patterns of...

  18. Early programming of the oocyte epigenome temporally controls late prophase I transcription and chromatin remodelling

    Navarro-Costa, Paulo; McCarthy, Alicia; Prudêncio, Pedro; Greer, Christina; Guilgur, Leonardo G.; Becker, Jörg D.; Secombe, Julie; Rangan, Prashanth; Martinho, Rui G.
    Oocytes are arrested for long periods of time in the prophase of the first meiotic division (prophase I). As chromosome condensation poses significant constraints to gene expression, the mechanisms regulating transcriptional activity in the prophase I-arrested oocyte are still not entirely understood. We hypothesized that gene expression during the prophase I arrest is primarily epigenetically regulated. Here we comprehensively define the Drosophila female germ line epigenome throughout oogenesis and show that the oocyte has a unique, dynamic and remarkably diversified epigenome characterized by the presence of both euchromatic and heterochromatic marks. We observed that the perturbation of the oocyte's epigenome...

  19. Identification and functional analysis of novel genes expressed in the Anterior Visceral Endoderm

    Goncalves, Lisa; Filipe, Mario; Marques, Sara; Salgueiro, Ana-Marisa; Becker, Jorg D.; Belo, Jose Antonio
    During early vertebrate development, the correct establishment of the body axes is critical. The anterior pole of the mouse embryo is established when Distal Visceral Endoderm (DVE) cells migrate to form the Anterior Visceral Endoderm (AVE). Symmetrical expression of Lefty1, Cer1 and Dkk1 determines the direction of DVE migration and the future anterior side. In addition to the establishment of the Anterior-Posterior axis, the AVE has also been implicated in anterior neural specification. To better understand the role of the AVE in these processes, we have performed a differential screening using Affymetrix GeneChip technology with AVE cells isolated from cer1P-EGFP...

  20. Expression-based and co-localization detection of arabinogalactan protein 6 and arabinogalactan protein 11 interactors in Arabidopsis pollen and pollen tubes

    Costa, Mário; Nobre, Margarida Sofia; Becker, Jörg D; Masiero, Simona; Amorim, Maria Isabel; Pereira, Luís Gustavo; Coimbra, Sílvia
    Arabinogalactan proteins (AGPs) are cell wall proteoglycans that have been shown to be important for pollen development. An Arabidopsis double null mutant for two pollen-specific AGPs (agp6 agp11) showed reduced pollen tube growth and compromised response to germination cues in vivo. A microarray experiment was performed on agp6 agp11 pollen tubes to search for genetic interactions in the context of pollen tube growth. A yeast two-hybrid experiment for AGP6 and AGP11 was also designed.

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