RESUMO
Polycyclic aromatic hydrocarbons (PAHs) are among the most persistent xenobiotic compounds, with high toxicity effects. Mycoremediation with halophilic Aspergillus sydowii was used for their removal from a hypersaline medium (1 M NaCl). A. sydowii metabolized PAHs as sole carbon sources, resulting in the removal of up to 90% for both PAHs [benzo [a] pyrene (BaP) and phenanthrene (Phe)] after 10 days. Elimination of Phe and BaP was almost exclusively due to biotransformation and not adsorption by dead mycelium and did not correlate with the activity of lignin modifying enzymes (LME). Transcriptomes of A. sydowii grown on PAHs, or on glucose as control, both at hypersaline conditions, revealed 170 upregulated and 76 downregulated genes. Upregulated genes were related to starvation, cell wall remodelling, degradation and metabolism of xenobiotics, DNA/RNA metabolism, energy generation, signalling and general stress responses. Changes of LME expression levels were not detected, while the chloroperoxidase gene, possibly related to detoxification processes in fungi, was strongly upregulated. We propose that two parallel metabolic pathways (mitochondrial and cytosolic) are involved in degradation and detoxification of PAHs in A. sydowii resulting in intracellular oxidation of PAHs. To the best of our knowledge, this is the most comprehensive transcriptomic analysis on fungal degradation of PAHs.
Assuntos
Hidrocarbonetos Policíclicos Aromáticos , Transcriptoma , Aspergillus/genética , Biodegradação Ambiental , Perfilação da Expressão Gênica , Transcriptoma/genéticaRESUMO
Metamorphosis is a postembryonic developmental process that involves morphophysiological and behavioral changes, allowing organisms to adapt into a novel environment. In some amphibians, aquatic organisms undergo metamorphosis to adapt in a terrestrial environment. In this process, these organisms experience major changes in their circulatory, respiratory, digestive, excretory and reproductive systems. We performed a transcriptional global analysis of heart, lung and gills during diverse stages of Ambystoma velasci to investigate its metamorphosis. In our analyses, we identified eight gene clusters for each organ, according to the expression patterns of differentially expressed genes. We found 4064 differentially expressed genes in the heart, 4107 in the lung and 8265 in the gills. Among the differentially expressed genes in the heart, we observed genes involved in the differentiation of cardiomyocytes in the interatrial zone, vasculogenesis and in the maturation of coronary vessels. In the lung, we found genes differentially expressed related to angiogenesis, alveolarization and synthesis of the surfactant protein. In the case of the gills, the most prominent biological processes identified are degradation of extracellular matrix, apoptosis and keratin production. Our study sheds light on the transcriptional responses and the pathways modulation involved in the transformation of the facultative metamorphic salamander A. velasci in an organ-specific manner.
Assuntos
Proteínas de Anfíbios/biossíntese , Embrião não Mamífero/embriologia , Regulação da Expressão Gênica no Desenvolvimento/fisiologia , Metamorfose Biológica/fisiologia , Transcriptoma/fisiologia , Ambystoma , Animais , Especificidade de Órgãos/fisiologiaRESUMO
Characterization of a protein of interest during development is essential for functional studies. A general strategy for understanding the function of a particular protein involves the generation of null mutations, or treatment with drugs, that interfere with its activity. To demonstrate that the synthesis, stability, or activity of a protein has been affected, accurate and efficient detection of low amounts of protein is essential. This can be achieved by immunohistochemistry or by western blot. Here we describe a method for the detection of proteins from single de-yolked zebrafish embryos. This procedure includes a fixation step and the concomitant elimination of lipids from the yolk cell. We show that this approach allows the rapid analysis of proteins in embryos without having to manually remove the yolk. This method provides a convenient alternative for genotyping of mutant embryos as early as the 128 cell stage. In addition, in drug- or morpholino-treated embryos, the correlation between the penetrance of a phenotype and the concentration of a protein present may be established.
Assuntos
Western Blotting/métodos , Embrião não Mamífero/química , Proteínas de Peixes/isolamento & purificação , Técnicas de Genotipagem/métodos , Peixe-Zebra , Animais , Peixe-Zebra/genética , Peixe-Zebra/crescimento & desenvolvimentoRESUMO
Cell movements are essential for morphogenesis during animal development. Epiboly is the first morphogenetic process in zebrafish in which cells move en masse to thin and spread the deep and enveloping cell layers of the blastoderm over the yolk cell. While epiboly has been shown to be controlled by complex molecular networks, the contribution of reactive oxygen species (ROS) to this process has not previously been studied. Here, we show that ROS are required for epiboly in zebrafish. Visualization of ROS in whole embryos revealed dynamic patterns during epiboly progression. Significantly, inhibition of NADPH oxidase activity leads to a decrease in ROS formation, delays epiboly, alters E-cadherin and cytoskeleton patterns and, by 24â¯h post-fertilization, decreases embryo survival, effects that are rescued by hydrogen peroxide treatment. Our findings suggest that a delicate ROS balance is required during early development and that disruption of that balance interferes with cell adhesion, leading to defective cell motility and epiboly progression.
Assuntos
Blastoderma/metabolismo , Citoesqueleto/metabolismo , NADPH Oxidases/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Peixe-Zebra/fisiologia , Animais , Caderinas/metabolismo , Adesão Celular , Movimento Celular , Embrião não Mamífero , Morfogênese , Proteínas de Peixe-Zebra/metabolismoRESUMO
Zebrafish germ plasm is composed of mRNAs such as vasa and nanos and of proteins such as Bucky ball, all of which localize symmetrically in four aggregates at the distal region of the first two cleavage furrows. The coordination of actin microfilaments, microtubules and kinesin is essential for the correct localization of the germ plasm. Rho-GTPases, through their effectors, coordinate cytoskeletal dynamics. We address the participation of RhoA and its effector ROCK in germ plasm localization during the transition from two- to eight-cell embryos. We found that active RhoA is enriched along the cleavage furrow during the first two division cycles, whereas ROCK localizes at the distal region of the cleavage furrows in a similar pattern as the germ plasm mRNAs. Specific inhibition of RhoA and ROCK affected microtubules organization at the cleavage furrow; these caused the incorrect localization of the germ plasm mRNAs. The incorrect localization of the germ plasm led to a dramatic change in the number of germ cells during the blastula and 24hpf embryo stages without affecting any other developmental processes. We demonstrate that the Rho/ROCK pathway is intimately related to the determination of germ cells in zebrafish embryos.
Assuntos
Embrião não Mamífero/metabolismo , Transdução de Sinais , Peixe-Zebra/embriologia , Peixe-Zebra/metabolismo , Quinases Associadas a rho/metabolismo , Proteína rhoA de Ligação ao GTP/metabolismo , Animais , Desenvolvimento Embrionário/genética , Imunofluorescência , Regulação da Expressão Gênica no Desenvolvimento , Células Germinativas/metabolismo , Microtúbulos/metabolismo , Miosinas/metabolismo , Transporte Proteico , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Peixe-Zebra/genética , Proteínas de Peixe-Zebra/genética , Proteínas de Peixe-Zebra/metabolismo , Proteína rhoA de Ligação ao GTP/antagonistas & inibidoresRESUMO
Antioxidant cellular mechanisms are essential for cell redox homeostasis during animal development and in adult life. Previous in situ hybridization analyses of antioxidant enzymes in zebrafish have indicated that they are ubiquitously expressed. However, spatial information about the protein distribution of these enzymes is not available. Zebrafish embryos are particularly suitable for this type of analysis due to their small size, transparency and fast development. The main objective of the present work was to analyze the spatial and temporal gene expression pattern of the two reported zebrafish glutathione peroxidase 4 (GPx4) genes during the first day of zebrafish embryo development. We found that the gpx4b gene shows maternal and zygotic gene expression in the embryo proper compared to gpx4a that showed zygotic gene expression in the periderm covering the yolk cell only. Following, we performed a GPx4 protein immunolocalization analysis during the first 24-h of development. The detection of this protein suggests that the antibody recognizes GPx4b in the embryo proper during the first 24 h of development and GPx4a at the periderm covering the yolk cell after 14-somite stage. Throughout early cleavages, GPx4 was located in blastomeres and was less abundant at the cleavage furrow. Later, from the 128-cell to 512-cell stages, GPx4 remained in the cytoplasm but gradually increased in the nuclei, beginning in marginal blastomeres and extending the nuclear localization to all blastomeres. During epiboly progression, GPx4b was found in blastoderm cells and was excluded from the yolk cell. After 24 h of development, GPx4b was present in the myotomes particularly in the slow muscle fibers, and was excluded from the myosepta. These results highlight the dynamics of the GPx4 localization pattern and suggest its potential participation in fundamental developmental processes.
Assuntos
Regulação da Expressão Gênica no Desenvolvimento , Glutationa Peroxidase/genética , Proteínas de Peixe-Zebra/genética , Animais , Blastoderma/metabolismo , Citocinese , Embrião não Mamífero , Desenvolvimento Embrionário , Glutationa Peroxidase/biossíntese , Glutationa Peroxidase/metabolismo , Hibridização In Situ , Isoenzimas , Mesoderma/metabolismo , Fosfolipídeo Hidroperóxido Glutationa Peroxidase , Peixe-Zebra , Proteínas de Peixe-Zebra/biossínteseRESUMO
The Zmiz2 (Zimp7) protein and its homolog Zmiz1 (Zimp10) were initially identified in humans as androgen receptor co-activators. Sequence analysis revealed the presence of an SP-RING/Miz domain, which is highly conserved in members of the PIAS family and confers SUMO-conjugating activity. Zimp7 has been shown to interact with components of the Wnt/ß-Catenin signaling pathway and with Brg1 and BAF57, components of the ATP-dependent mammalian SWI/SNF-like BAF chromatin-remodeling complexes. In this work, we analyze the role of zygotic Zimp7 in zebrafish development. We describe evidence indicating that Zimp7 is required for mesoderm development and dorsoventral patterning. Morpholino-mediated reduction of zygotic Zimp7 produced axial mesodermal defects that were preceded by up-regulation of organizer genes such as bozozok, goosecoid and floating head at the onset of gastrulation and by down-regulation of the ventral markers vox, vent and eve1 indicating loss of the ventrolateral mesoderm. Consistently, embryos overexpressing zimp7 RNA exhibited midline defects such as loss of forebrain and cyclopia accompanied by transcriptional changes directly opposite of those found in the morphants. In addition, the patterning of ventralized embryos produced by the overexpression of vox and vent was restored by a reduction of Zimp7 activity. Altogether, our findings indicate that Zimp7 is involved in transcriptional regulation of factors that are essential for patterning in the dorsoventral axis.