843 research outputs found
Contribución al estudio de la entomofauna del Monte del Estado Selladores-Contadero (Jaén)
By sundry capture methods it is achieved an insect collecting in 6 plots that are located in Monte de Selladores-Contadero, Jaén (Spain). The taxonomic analysis about 4.787 specimen gives as a result the identification of 275 species belonging at 12 Orders and 82 Families.Mediante diversos métodos de captura se realiza una recolección de insectos en 6 parcelas ubicadas en el Monte de Selladores-Contadero (Jaén). El análisis taxonómico sobre 4.787 especímenes, ofrece como resultado la identificación de 275 especies correspondientes a 12 Órdenes y 82 Familias
Degeneración Basal versus Degeneración Superficial en la Condromalacia Rotuliana
Se hace un estudio en base a las muestras tisulares procedentes de pacientes
afectos de condromalacia rotuliana, artrosis y dos casos considerados
como testigos. Los hallazgos morfológicos son bastantes similares en
los casos de condromalacia rotuliana y artrosis, lo que parece indicar que
la condromalacia puede considerarse como un estado preartrósico patelar,
si bien en esta son más acusados los fenómenos de rarefacción de la matriz
del cartílago superficial y medio de la rótula.A special study with samples of tissue s from some patients
suffering chondromalacia patellae, arthrosis, and two patients as
control, is made. The morphological findings are quite similar in
both case s of chondromalacia patellae and arthrosis. Therefore
chondromalacia can be consider as a prearthrosis patellar stadium,
although in the chondromalacia state, the fenomenous of
rarefaction in the matrix of cartilage, superficial and middle of the
rotula, are more important
The Physcomitrella patens unique alpha-dioxygenase participates in both developmental processes and defense responses
[Background] Plant α-dioxygenases catalyze the incorporation of molecular oxygen into polyunsaturated fatty acids leading to the formation of oxylipins. In flowering plants, two main groups of α-DOXs have been described. While the α-DOX1 isoforms are mainly involved in defense responses against microbial infection and herbivores, the α-DOX2 isoforms are mostly related to development. To gain insight into the roles played by these enzymes during land plant evolution, we performed biochemical, genetic and molecular analyses to examine the function of the single copy moss Physcomitrella patens α-DOX (Ppα-DOX) in development and defense against pathogens.[Results] Recombinant Ppα-DOX protein catalyzed the conversion of fatty acids into 2-hydroperoxy derivatives with a substrate preference for α-linolenic, linoleic and palmitic acids. Ppα-DOX is expressed during development in tips of young protonemal filaments with maximum expression levels in mitotically active undifferentiated apical cells. In leafy gametophores, Ppα-DOX is expressed in auxin producing tissues, including rhizoid and axillary hairs. Ppα-DOX transcript levels and Ppα-DOX activity increased in moss tissues infected with Botrytis cinerea or treated with Pectobacterium carotovorum elicitors. In B. cinerea infected leaves, Ppα-DOX-GUS proteins accumulated in cells surrounding infected cells, suggesting a protective mechanism. Targeted disruption of Ppα-DOX did not cause a visible developmental alteration and did not compromise the defense response. However, overexpressing Ppα-DOX, or incubating wild-type tissues with Ppα-DOX-derived oxylipins, principally the aldehyde heptadecatrienal, resulted in smaller moss colonies with less protonemal tissues, due to a reduction of caulonemal filament growth and a reduction of chloronemal cell size compared with normal tissues. In addition, Ppα-DOX overexpression and treatments with Ppα-DOX-derived oxylipins reduced cellular damage caused by elicitors of P. carotovorum.[Conclusions] Our study shows that the unique α-DOX of the primitive land plant P. patens, although apparently not crucial, participates both in development and in the defense response against pathogens, suggesting that α-DOXs from flowering plants could have originated by duplication and successive functional diversification after the divergence from bryophytes.This work was supported by Agencia Nacional de Investigación e Innovación (ANII) [grants FCE2007_376, FCE2011_6095, fellowships BE_POS_2009_726 (A. Castro) and BE_POS_2010_2533 (L. Machado)], UdelaR Uruguay/CSIC Spain (Joint project), the Swedish Research Council, and Programa de Desarrollo de las Ciencias Básicas (PEDECIBA) Uruguay. The Ppα-DOX cDNA was obtained from the RIKEN Biological Research Center, Tsukuba, Japan
Silencing of histone deacetylase 6 decreases cellular malignancy and contributes to primary cilium restoration, epithelial-to-mesenchymal transition reversion, and autophagy inhibition in glioblastoma cell lines
Glioblastoma multiforme, the most common type of malignant brain tumor as well as the most aggressive one, lacks an effective therapy. Glioblastoma presents overexpression of mesenchymal markers Snail, Slug, and N-Cadherin and of the autophagic marker p62. Glioblastoma cell lines also present increased autophagy, overexpression of mesenchymal markers, Shh pathway activation, and lack of primary cilia. In this study, we aimed to evaluate the role of HDAC6 in the pathogenesis of glioblastoma, as HDAC6 is the most overexpressed of all HDACs isoforms in this tumor. We treated glioblastoma cell lines with siHDAC6. HDAC6 silencing inhibited proliferation, migration, and clonogenicity of glioblastoma cell lines. They also reversed the mesenchymal phenotype, decreased autophagy, inhibited Shh pathway, and recovered the expression of primary cilia in glioblastoma cell lines. These results demonstrate that HDAC6 might be a good target for glioblastoma treatment
Identification of a methylase required for 2-methylhopanoid production and implications for the interpretation of sedimentary hopanes
The rise of atmospheric oxygen has driven environmental change and biological evolution throughout much of Earth’s history and was enabled by the evolution of oxygenic photosynthesis in the cyanobacteria. Dating this metabolic innovation using inorganic proxies from sedimentary rocks has been difficult and one important approach has been to study the distributions of fossil lipids, such as steranes and 2-methylhopanes, as biomarkers for this process. 2-methylhopanes arise from degradation of 2-methylbacteriohopanepolyols (2-MeBHPs), lipids thought to be synthesized primarily by cyanobacteria. The discovery that 2-MeBHPs are produced by an anoxygenic phototroph, however, challenged both their taxonomic link with cyanobacteria and their functional link with oxygenic photosynthesis. Here, we identify a radical SAM methylase encoded by the hpnP gene that is required for methylation at the C-2 position in hopanoids. This gene is found in several, but not all, cyanobacteria and also in α -proteobacteria and acidobacteria. Thus, one cannot extrapolate from the presence of 2-methylhopanes alone, in modern environments or ancient sedimentary rocks, to a particular taxonomic group or metabolism. To understand the origin of this gene, we reconstructed the evolutionary history of HpnP. HpnP proteins from cyanobacteria, Methylobacterium species, and other α-proteobacteria form distinct phylogenetic clusters, but the branching order of these clades could not be confidently resolved. Hence,it is unclear whether HpnP, and 2-methylhopanoids, originated first in the cyanobacteria. In summary, existing evidence does not support the use of 2-methylhopanes as biomarkers for oxygenic photosynthesis
Molecular phylogenetic studies on the lichenicolous Xanthoriicola physciae reveal Antarctic rock-inhabiting fungi and Piedraia species among closest relatives in the Teratosphaeriaceae
The phylogenetic placement of the monotypic dematiaceous hyphomycete genus Xanthoriicola was investigated. Sequences of the nLSU region were obtained from 11 specimens of X. physciae, which formed a single clade supported both by parsimony (91 %), and maximum likelihood (100 %) bootstraps, and Bayesian Posterior Probabilities (1.0). The closest relatives in the parsimony analysis were species of Piedraria, while in the Bayesian analysis they were those of Friedmanniomyces. These three genera, along with species of Elasticomyces, Recurvomyces, Teratosphaeria, and sequences from unnamed rock-inhabiting fungi (RIF), were all members of the same major clade within Capnodiales with strong support in both analyses, and for which the family name Teratosphaeriaceae can be used pending further studies on additional taxa
Groups without cultured representatives dominate eukaryotic picophytoplankton in the oligotrophic South East Pacific Ocean
Background: Photosynthetic picoeukaryotes (PPE) with a cell size less than 3 µm play a critical role in oceanic primary production. In recent years, the composition of marine picoeukaryote communities has been intensively investigated by molecular approaches, but their photosynthetic fraction remains poorly characterized. This is largely because the classical approach that relies on constructing 18S rRNA gene clone libraries from filtered seawater samples using universal eukaryotic primers is heavily biased toward heterotrophs, especially alveolates and stramenopiles, despite the fact that autotrophic cells in general outnumber heterotrophic ones in the euphotic zone.
Methodology/Principal Findings: In order to better assess the composition of the eukaryotic picophytoplankton in the South East Pacific Ocean, encompassing the most oligotrophic oceanic regions on earth, we used a novel approach based on flow cytometry sorting followed by construction of 18S rRNA gene clone libraries. This strategy dramatically increased the recovery of sequences from putative autotrophic groups. The composition of the PPE community appeared highly variable both vertically down the water column and horizontally across the South East Pacific Ocean. In the central gyre, uncultivated lineages dominated: a recently discovered clade of Prasinophyceae (IX), clades of marine Chrysophyceae and Haptophyta, the latter division containing a potentially new class besides Prymnesiophyceae and Pavlophyceae. In contrast, on the edge of the gyre and in the coastal Chilean upwelling, groups with cultivated representatives (Prasinophyceae clade VII and Mamiellales) dominated.
Conclusions/Significance: Our data demonstrate that a very large fraction of the eukaryotic picophytoplankton still escapes cultivation. The use of flow cytometry sorting should prove very useful to better characterize specific plankton populations by molecular approaches such as gene cloning or metagenomics, and also to obtain into culture strains representative of these novel groups
Highly Dynamic Exon Shuffling in Candidate Pathogen Receptors … What if Brown Algae Were Capable of Adaptive Immunity?
Pathogen recognition is the first step of immune reactions. In animals and plants, direct or indirect pathogen recognition is often mediated by a wealth of fast-evolving receptors, many of which contain ligand-binding and signal transduction domains, such as leucine-rich or tetratricopeptide repeat (LRR/TPR) and NB-ARC domains, respectively. In order to identify candidates potentially involved in algal defense, we mined the genome of the brown alga Ectocarpus siliculosus for homologues of these genes and assessed the evolutionary pressures acting upon them. We thus annotated all Ectocarpus LRR-containing genes, in particular an original group of LRR-containing GTPases of the ROCO family, and 24 NB-ARC–TPR proteins. They exhibit high birth and death rates, while a diversifying selection is acting on their LRR (respectively TPR) domain, probably affecting the ligand-binding specificities. Remarkably, each repeat is encoded by an exon, and the intense exon shuffling underpins the variability of LRR and TPR domains. We conclude that the Ectocarpus ROCO and NB-ARC–TPR families are excellent candidates for being involved in recognition/transduction events linked to immunity. We further hypothesize that brown algae may generate their immune repertoire via controlled somatic recombination, so far only known from the vertebrate adaptive immune systems
Protein stability and interaction of the nicotinic acetylcholine receptor with cholinergic ligands studied by Fourier-transform infrared spectroscopy
TP53, ATRX alterations, and low tumor mutation load feature IDH-wildtype giant cell glioblastoma despite exceptional ultra-mutated tumors
Background: Giant cell glioblastoma (gcGBM) is a rare morphological variant of IDH-wildtype (IDHwt) GBM that occurs in young adults and have a slightly better prognosis than "classic" IDHwt GBM. Methods: We studied 36 GBMs, 14 with a histopathological diagnosis of gcGBM and 22 with a giant cell component. We analyzed the genetic profile of the most frequently mutated genes in gliomas and assessed the tumor mutation load (TML) by gene-targeted next-generation sequencing. We validated our findings using The Cancer Genome Atlas (TCGA) data. Results: p53 was altered by gene mutation or protein overexpression in all cases, while driver IDH1, IDH2, BRAF, or H3F3A mutations were infrequent or absent. Compared to IDHwt GBMs, gcGBMs had a significant higher frequency of TP53, ATRX, RB1, and NF1 mutations, while lower frequency of EGFR amplification, CDKN2A deletion, and TERT promoter mutation. Almost all tumors had low TML values. The high TML observed in only 2 tumors was consistent with POLE and MSH2 mutations. In the histopathological review of TCGA IDHwt, TP53-mutant tumors identified giant cells in 37% of the cases. Considering our series and that of the TCGA, patients with TP53-mutant gcGBMs had better overall survival than those with TP53wt GBMs (log-rank test, P < .002). Conclusions: gcGBMs have molecular features that contrast to "classic" IDHwt GBMs: unusually frequent ATRX mutations and few EGFR amplifications and CDKN2A deletions, especially in tumors with a high number of giant cells. TML is frequently low, although exceptional high TML suggests a potential for immune checkpoint therapy in some cases, which may be relevant for personalized medicine
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