La diversidad palinológica y los cambios climáticos en el Paleozoico Superior en Brasil y Uruguay

We have analysed the diversity of the late Paleozoic palynoflora of the Paraná (Brazil and Uruguay), Parnaíba and Amazon (Brazil) basins using already published data. In order to do this the total diversity and diversity with range-through approach curves were built up, as well as Foote’s appearance and disappearance rates at the generic level. These parameters were also obtained separately for each group of sporomorphs. An important increase in diversity in the Asselian and Sakmarian and a posterior decrease until the Lopingian were observed. The values of the appearance rates were higher than those of disappearance and they peaked in the Asselian, while the highest disappearances took place in the Capitanian and, to a lesser extent, in the Sakmarian. On the other hand, spores and pollen grains show some differences in the general diversity trend. However, there are differences in the patterns of appearance and disappearance. Despite possible biases, mainly related to the collecting effort, the diversity curves and appearance and disappearance rates obtained are congruent with the climatic phases proposed for this region in these periods. The increase in the number of palynomorph genera is associated to the early Permian climatic amelioration whilst a decrease in diversity is related to the beginning of an arid phase.Se analizó la diversidad de la palinoflora correspondiente a estratos del Paleozoico superior de las cuencas de Paraná (Brasil y Uruguay), Parnaíba y Amazonas (Brasil), utilizando datos previamente publicados. Se elaboraron curvas de diversidad total y diversidad calculadas mediante el método range-through y se calcularon los índices de aparición y desaparición de los diferentes géneros utilizando como herramienta el índice de Foote. También se analizaron esos parámetros en diferentes grupos de esporomorfos por separado. Se observó un aumento importante de la diversidad en el Asseliano y Sakmariano y una posterior disminución gradual hasta el Lopingiano. Los valores de los índices de aparición fueron más importantes que los de desaparición y se dieron en el Asseliano, mientras que las mayores desapariciones se observaron en el Capitaniano y en menor medida en el Sakmariano. Por otra parte, las esporas y los granos de polen presentan algunas diferencias en la tendencia general de diversidad. Sin embargo, se aprecian diferencias en los patrones de aparición y desaparición. A pesar de los posibles sesgos, fundamentalmente relacionados con el esfuerzo de colecta, existe cierta coherencia entre la diversidad, los índices de apariciones y desapariciones y las fases climáticas propuestas para esa edad en la región. El cambio hacia un clima más templado ocurrido en el Pérmico inferior estaría asociado a un aumento en el número de géneros de palinomorfos mientras que el comienzo de una fase más árida estaría relacionado a una disminución en la diversidad

Epigenetic loss of the transfer RNA-modifying enzyme TYW2 induces ribosome frameshifts in colon cancer

Altres ajuts: Funding for this research was provided by the Asociación Española Contra el Cáncer Scientific Foundation (Accelerator Award A26825); and the Olga Torres Foundation.Transfer RNA (tRNA) activity is tightly regulated to provide a physiological protein translation, and tRNA chemical modifications control its function in a complex with ribosomes and messenger RNAs (mRNAs). In this regard, the correct hypermodification of position G37 of phenylalanine-tRNA, adjacent to the anticodon, is critical to prevent ribosome frameshifting events. Here we report that the tRNA-yW Synthesizing Protein 2 (TYW2) undergoes promoter hypermethylation-associated transcriptional silencing in human cancer, particularly in colorectal tumors. The epigenetic loss of TYW2 induces guanosine hypomodification in phenylalanine-tRNA, an increase in -1 ribosome frameshift events, and down-regulation of transcripts by mRNA decay, such as of the key cancer gene ROBO1. Importantly, TYW2 epigenetic inactivation is linked to poor overall survival in patients with early-stage colorectal cancer, a finding that could be related to the observed acquisition of enhanced migration properties and epithelial-to-mesenchymal features in the colon cancer cells that harbor TYW2 DNA methylation-associated loss. These findings provide an illustrative example of how epigenetic changes can modify the epitranscriptome and further support a role for tRNA modifications in cancer biology

Epigenetic inactivation of the splicing RNA-binding protein CELF2 in human breast cancer

Altres ajuts: This work was co-finaced by the European Development Regional Fund, "A way to achieve Europe" ERDF; the Cellex Foundation; and "la Caixa" Banking Foundation (LCF/PR/PR15/ 11100003).Human tumors show altered patterns of protein isoforms that can be related to the dysregulation of messenger RNA alternative splicing also observed in transformed cells. Although somatic mutations in core spliceosome components and their associated factors have been described in some cases, almost nothing is known about the contribution of distorted epigenetic patterns to aberrant splicing. Herein, we show that the splicing RNA-binding protein CELF2 is targeted by promoter hypermethylation-associated transcriptional silencing in human cancer. Focusing on the context of breast cancer, we also demonstrate that CELF2 restoration has growth-inhibitory effects and that its epigenetic loss induces an aberrant downstream pattern of alternative splicing, affecting key genes in breast cancer biology such as the autophagy factor ULK1 and the apoptotic protein CARD10. Furthermore, the presence of CELF2 hypermethylation in the clinical setting is associated with shorter overall survival of the breast cancer patients carrying this epigenetic lesion

Look-alike humans identified by facial recognition algorithms show genetic similarities

We thank François Brunelle for providing the look-alike images. We thank CERCA Programme/Generalitat de Catalunya and the Josep Carreras Foundation for institutional support. This work was funded by the governments of Catalonia (2017SGR1080) and Spain (RTI2018-094049-B-I00, SAF2014-55000, and TIN2017-90124-P) and the Cellex Foundation. M.E. conceived and designed the study; R.S.J. M.R. C.A.G.-P. M.C.d.M. D.P. S.M. V.D. P.C. M.F.-B. I.O. C.L.-F. A.N. C.F.-T. D.A. F.M.S. X.B. A.V. and M.E. analyzed multiomics and questionnaire data; R.J. and M.E. wrote the manuscript with contributions and approval from all authors. M.E. is a consultant of Ferrer International and Quimatryx. S.M. is an employee of Ferrer International. C.F.-T. is chief technical officer of Herta Security.We thank François Brunelle for providing the look-alike images. We thank CERCA Programme/Generalitat de Catalunya and the Josep Carreras Foundation for institutional support. This work was funded by the governments of Catalonia (2017SGR1080) and Spain (RTI2018-094049-B-I00, SAF2014-55000, and TIN2017-90124-P) and the Cellex Foundation.The human face is one of the most visible features of our unique identity as individuals. Interestingly, monozygotic twins share almost identical facial traits and the same DNA sequence but could exhibit differences in other biometrical parameters. The expansion of the world wide web and the possibility to exchange pictures of humans across the planet has increased the number of people identified online as virtual twins or doubles that are not family related. Herein, we have characterized in detail a set of "look-alike" humans, defined by facial recognition algorithms, for their multiomics landscape. We report that these individuals share similar genotypes and differ in their DNA methylation and microbiome landscape. These results not only provide insights about the genetics that determine our face but also might have implications for the establishment of other human anthropometric properties and even personality characteristics

Purification and biochemical characterization of four iron superoxide dismutases in Trypanosoma cruzi

Four superoxide dismutase (SOD) activities (SOD I, II, III, and IV) have been characterized in the epimastigote form of Trypanosoma cruzi . The total extract was subjected to two successive ammonium sulphate additions between 35 and 85%, and the resulting fraction was purified using two continuous chromatography processes (ion exchange and filtration). Enzymes were insensitive to cyanide but sensitive to hydrogen peroxide, properties characteristic of iron-containing SODs. The molecular masses of the different SODs were 20 kDa (SOD I), 60 kDa (SOD II), 50 kDa (SOD III) and 25 kDa (SOD IV), whereas the isoelectric points were 6.9, 6.8, 5.2 and 3.8, respectively. Subcellular location and digitonin experiments have shown that these SODs are mainly cytosolic, with small amounts in the low- mass organelles (SOD II and SOD I) and the mitochondrion (SOD III), where these enzymes play an important role in minimizing oxidative damage.Financial support: CGL2006-27889-E/BOS, Ministerio de Ciencia y Tecnología

Gene Flow in Genetically Modified Wheat

Understanding gene flow in genetically modified (GM) crops is critical to answering questions regarding risk-assessment and the coexistence of GM and non-GM crops. In two field experiments, we tested whether rates of cross-pollination differed between GM and non-GM lines of the predominantly self-pollinating wheat Triticum aestivum. In the first experiment, outcrossing was studied within the field by planting “phytometers” of one line into stands of another line. In the second experiment, outcrossing was studied over distances of 0.5–2.5 m from a central patch of pollen donors to adjacent patches of pollen recipients. Cross-pollination and outcrossing was detected when offspring of a pollen recipient without a particular transgene contained this transgene in heterozygous condition. The GM lines had been produced from the varieties Bobwhite or Frisal and contained Pm3b or chitinase/glucanase transgenes, respectively, in homozygous condition. These transgenes increase plant resistance against pathogenic fungi. Although the overall outcrossing rate in the first experiment was only 3.4%, Bobwhite GM lines containing the Pm3b transgene were six times more likely than non-GM control lines to produce outcrossed offspring. There was additional variation in outcrossing rate among the four GM-lines, presumably due to the different transgene insertion events. Among the pollen donors, the Frisal GM line expressing a chitinase transgene caused more outcrossing than the GM line expressing both a chitinase and a glucanase transgene. In the second experiment, outcrossing after cross-pollination declined from 0.7–0.03% over the test distances of 0.5–2.5 m. Our results suggest that pollen-mediated gene flow between GM and non-GM wheat might only be a concern if it occurs within fields, e.g. due to seed contamination. Methodologically our study demonstrates that outcrossing rates between transgenic and other lines within crops can be assessed using a phytometer approach and that gene-flow distances can be efficiently estimated with population-level PCR analyses

Epigenetic loss of RNA-methyltransferase NSUN5 in glioma targets ribosomes to drive a stress adaptive translational program

Altres ajuts: This work was supported by the Obra Social "La Caixa" (to M. Esteller).Tumors have aberrant proteomes that often do not match their corresponding transcriptome profiles. One possible cause of this discrepancy is the existence of aberrant RNA modification landscapes in the so-called epitranscriptome. Here, we report that human glioma cells undergo DNA methylation-associated epigenetic silencing of NSUN5, a candidate RNA methyltransferase for 5-methylcytosine. In this setting, NSUN5 exhibits tumor-suppressor characteristics in vivo glioma models. We also found that NSUN5 loss generates an unmethylated status at the C3782 position of 28S rRNA that drives an overall depletion of protein synthesis, and leads to the emergence of an adaptive translational program for survival under conditions of cellular stress. Interestingly, NSUN5 epigenetic inactivation also renders these gliomas sensitive to bioactivatable substrates of the stress-related enzyme NQO1. Most importantly, NSUN5 epigenetic inactivation is a hallmark of glioma patients with long-term survival for this otherwise devastating disease