clinica bien reconocida, no se tiene aun definicion totalmente satisfactoria. Antihistaminicos no ayudan Eicosanoides: cicloxigenasa. Eicosanoides tromboxanos. X. X. X: inhibición por antiinflamatorios no esteroideos. Page ▫ Prostaglandinas: ▫ Se descubrieron en la glándula prostática. oxidación de ácidos grasos específicos, catabolismo de poliaminas, prostaglan- dinas, eicosanoides y en la biosíntesis de esteroles y plasmalógenos (que.
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The head-regeneration transcriptome of the planarian Schmidtea mediterranea. Background Planarian flatworms can regenerate their head, including a functional brain, within less than a week. Despite the enormous potential of these animals for medical research and regenerative medicine, the mechanisms of eicosanoifes and the molecules involved remain largely unknown.
Results To identify genes that are differentially expressed during early stages of planarian head regeneration, we generated a de novo transcriptome assembly from more than million paired-end reads from planarian fragments regenerating the head at 16 different time points. The assembly yielded 26, putative transcripts, including very long transcripts spanning multiple genomic supercontigs, and thousands of isoforms. Using short-read data from two platforms, we analyzed dynamic gene regulation during the first three days of head regeneration.
We identified at least five different temporal synexpression classes, including genes specifically induced within a few hours after injury. Furthermore, we characterized the role of a conserved Runx transcription factor, smed-runt-like1. RNA interference RNAi knockdown and immunofluorescence analysis of the regenerating visual system indicated that smed-runt-like1 encodes a transcriptional regulator drfinicion eye morphology and photoreceptor patterning.
Conclusions Transcriptome sequencing of short reads allowed for the simultaneous de novo assembly and differential expression analysis of transcripts, demonstrating highly dynamic regulation during head regeneration in planarians. Directory of Open Access Journals Sweden. Full Text Available Melanins are ubiquitous and biologically important pigments, yet the molecular mechanisms that regulate their synthesis and biochemical composition are not fully understood.
Here we present a study that supports a role for serotonin in melanin synthesis in the planarian Schmidtea mediterranea. We characterize the tryptophan hydroxylase tph gene, which encodes the rate-limiting enzyme in serotonin synthesis, and demonstrate by RNA interference that tph is essential for melanin production in the pigment cups of the planarian photoreceptors.
We exploit this phenotype to investigate the biological function eicosanoldes pigment cups using a quantitative light-avoidance behavioral assay.
Planarians lacking eye pigment remain phototactic, indicating that eye pigmentation is not essential for light avoidance in S. Finally, we show that the eye pigmentation defect observed in tph knockdown animals can be rescued by injection of either the product of TPH, 5-hydroxytryptophan 5-HTP, or serotonin.
Together, these results highlight a role for serotonin in melanogenesis, perhaps as a regulatory signal or as a pigment substrate. To our knowledge, this is the first example of this relationship to be reported outside of mammalian systems.
Neoblast Specialization in Regeneration of the Planarian Schmidtea mediterranea. Full Text Available Planarians can regenerate any missing body part in a process requiring dividing cells called neoblasts. Historically, neoblasts have largely been considered a homogeneous stem cell population. Most studies, however, analyzed neoblasts at the population rather than the single-cell level, leaving the degree of heterogeneity in this population unresolved.
We combined RNA sequencing of neoblasts from wounded planarians with expression screening and identified 33 transcription factors transcribed in specific differentiated cells and in small fractions of neoblasts during regeneration. Many neoblast subsets expressing distinct tissue-associated transcription factors were present, suggesting candidate specification into many lineages.
Together, these results suggest that specification of cell fate for most-to-all regenerative lineages occurs within neoblasts, with regenerative cells of blastemas being generated from a highly heterogeneous collection of lineage-specified neoblasts.
planarian schmidtea mediterranea: Topics by
The ovary of the freshwater planarian Schmidtea mediterranea has been studied for the first time definicon both light and electron microscopy methods. The ultrastructure of the ovary revealed two types of cells: Initially, oogonia underwent cytoplasm growth due to the development of organelles, such as endoplasmic reticulum, Golgi complex, and mitochondria, which are all involved vefinicion the production of cytoplasmic inclusions or yolk globules.
It is shown that the chromatoid body and fibrogranular aggregates may participate in the synthesis of vitelline inclusions. When completely mature, the oocytes have become larger, due sefinicion the accumulation of nutritive inclusions, which are round in shape and have a paracrystalline structure.
These inclusions are interpreted as being yolk globules and may represent a kind of nutritive material for the developing embryo. These ultrastructural features of the ovary agree with the available phylogenetic tree, based on morphological and karyological characters that considers Schmidtea group as a genus and not a subgenus. The presence of sperm between the oocytes suggests definifion fertilization may occur within the ovary, representing an uncommon condition within the Triclads, in which fertilization usually takes places outside of the ovaries.
Published by Elsevier SAS. Identification of multiple isomeric core chitobiose-modified high-mannose and paucimannose N-glycans in the planarian Schmidtea mediterranea. Cell surface-associated glycans mediate many cellular processes, including adhesion, migration, signaling, and extracellular matrix organization.
The galactosylation of core fucose GalFuc epitope in paucimannose and complex-type N -glycans is characteristic of protostome organisms, including flatworms eefinicion. Although uninvestigated, the structures of these glycans may play a role in planarian regeneration.
Di- and trigalactosylated core fucoses were the most dominant glycomers.
N -Glycans showed extensive, yet selective, methylation patterns, ranging from non-methylated to polymethylated glycoforms. Although the majority of glycoforms were polymethylated, a small fraction also consisted of non-methylated glycans. Remarkably, monogalactosylated core fucose remained unmethylated, whereas its polygalactosylated forms were methylated, indicating structurally selective methylation. The presence of two GALT-1 homologs suggests different requirements for mono- and polygalactosylation of core fucose for the formation of multiple isomers.
Furthermore, we observed variations in core definiciln glycosylation patterns in different planarian strains, suggesting evolutionary defiinicion in fucose glycosylation. These results contribute greatly to our understanding of N -glycan biosynthesis and suggest the presence of a. The miR family of microRNAs is crucial for regeneration of the brain and visual system in the planarian Schmidtea mediterranea.
Brain regeneration in planarians is mediated by precise spatiotemporal control of gene expression and is crucial for multiple aspects of neurogenesis. However, the mechanisms underpinning the gene regulation essential for brain regeneration are largely unknown. Here, we investigated the role of the miR family of microRNAs in planarian brain regeneration. The miR family miR is highly conserved in animals and regulates neurogenesis by facilitating neural differentiation, yet its role in neural wiring and brain organization is not known.
We developed a novel method for delivering anti-miRs using liposomes for the functional knockdown of microRNAs. Smed-miR knockdown revealed a key role for these microRNAs in neuronal organization during planarian brain regeneration. Our results also demonstrated an essential role for miR in the generation of eye progenitors. Additionally, miR regulates Smed-slit-1which encodes an axon guidance protein, either by targeting slit-1 mRNA or, potentially, by modulating the canonical Notch pathway. Together, our results sefinicion a role for miR in regulating the regeneration of a functional brain and visual system.
Glosario de Inmunología
Published by The Company of Biologists Ltd. Full Text Available Abstract Background Schmidtea mediterranea Platyhelminthes, Tricladida, Continenticola eicosqnoides found in scattered localities on a eicosanoices islands and in coastal areas of the western Mediterranean.
Its present distribution has been proposed to stem from the fragmentation and migration of the Corsica-Sardinia microplate during the formation of the western Mediterranean basin, which implies an ancient origin for the species. To test this hypothesis, we obtained a large number of samples from across its distribution area. Using known and new molecular markers and, for the first time in planariansa molecular clock, we analysed the genetic variability and demographic parameters within the species and between its sexual and asexual populations to estimate when they diverged.
Molecular data clustered the studied populations into three groups that correspond to the west, central and southeastern geographical locations of the current distribution of S.
Mitochondrial genes show low haplotype and nucleotide diversity within populations but demonstrate higher values when all individuals are considered. The nuclear marker shows higher values of genetic diversity than the mitochondrial genes at the population level, but asexual populations present lower variability than the sexual ones.
Neutrality tests are significant for some populations. Phylogenetic and dating analyses show the three groups to be monophyletic, with the west group being the basal group.
The repertoire of G protein-coupled receptors in the human parasite Schistosoma mansoni and the model organism Schmidtea mediterranea. Full Text Available Abstract Background G protein-coupled receptors GPCRs constitute one of the largest groupings of eukaryotic proteins, and represent a particularly lucrative set of pharmaceutical targets. They play an important role in eukaryotic signal transduction and physiology, mediating cellular responses to a diverse range of extracellular stimuli.
The phylum Platyhelminthes is of considerable medical and biological importance, housing major pathogens as well as established model organisms. The recent availability of genomic data for the human blood fluke Schistosoma mansoni and the model planarian Schmidtea mediterranea paves the way for the first comprehensive effort to identify and analyze GPCRs in this important phylum.
Results Application of a novel transmembrane-oriented approach to receptor mining led to the discovery of S. Among these, we report the identification of novel receptor groupings, including a large and highly-diverged Platyhelminth-specific Rhodopsin subfamily, a planarian -specific Adhesion-like family, and atypical Glutamate-like receptors.
Phylogenetic analysis was carried out following extensive gene curation. Support vector machines SVMs were trained and used for ligand-based classification of full-length Rhodopsin GPCRs, complementing phylogenetic and homology-based classification.
Conclusions Genome-wide investigation of GPCRs in two platyhelminth genomes reveals an extensive and complex receptor signaling repertoire with many unique features. This work provides important sequence and functional leads for understanding basic flatworm receptor biology, and sheds light on a lucrative set of anthelmintic drug targets.
Nuclear receptors NRsor nuclear hormone receptors NHRsare transcription factors that regulate development and metabolism of most if not all animal species. Their regulatory networks include conserved mechanisms that are shared in-between species as well as mechanisms that are restricted to certain phyla or even species. The derived amino acid sequence shows a high degree of conservation of both DNA-binding domain and ligand- binding domain and a remarkably high homology to vertebrate NR2E1 and C.
Quantitative PCR detected approximately ten-fold higher expression of Smed-tlx-1 in eicoosanoides proximal part of the head compared to the tail region. The expression of Smed-tlx-1 is higher during fed state than during fasting. Smed-tlx-1 down-regulation by RNA interference affects the ability of the animals to maintain body plan and induces defects of brain, eyes and defiicion shape during fasting and re-growing cycles.
Although the 18S rDNA belongs to a multigene family, all its copies are kept homogeneous by concerted evolution Dover ; Hillis and Dixon To date, there is only one well-characterized exception to this rule, the protozoan Plasmodium Gunderson et al. Here we report the vefinicion case of 18S rDNA polymorphism within a metazoan species. Southern blot analysis suggested that both types of rDNA are present in the genome of this flatworm. This was confirmed through sequence comparisons and phylogenetic analysis using the iecosanoides method and bootstrap test.
Although secondary structure analysis suggests that both types are functional, only type I seems to be transcribed to RNA, as demonstrated by Northern blot analysis. The finding of different types of 18S rDNAs in a single genome stresses the need for analyzing a large number of clones whenever 18S sequences refinicion by PCR amplification and cloning are being used in phylogenetic reconstruction.
Full Text Available Among the millions of invertebrate species with visual systems, the genetic basis of eye development and function is well understood only in Drosophila melanogaster. We describe an eye transcriptome for the planarian Schmidtea mediterranea.
Planarian photoreceptors expressed orthologs of genes required for phototransduction and microvillus structure in Drosophila and vertebrates, and optic pigment cells expressed solute transporters and melanin synthesis enzymes similar to those active in the vertebrate retinal pigment epithelium.
Orthologs of several planarian eye genes, such as bestrophin-1 and Usher syndrome genes, cause eye defects in mammals when perturbed and were not previously described to have roles in invertebrate eyes. Five previously undescribed planarian eye transcription factors defunicion required for normal eye formation during head regeneration. Transcriptome analysis of the planarian eye identifies ovo as a specific regulator of eye regeneration.
Among the millions of invertebrate species with visual systems, the genetic basis of eye development and eicosanoidfs is well understood only in Drosophila melanogaster. In particular, a conserved, transcription-factor-encoding ovo definiciin was expressed from the earliest stages of eye regeneration and was required for regeneration of all cell types of the eye. Published by Eicosnaoides Inc.