Suchergebnisse

Hernández Toledo, Sebastián. La persistencia en el exilio. Redes político- intelectuales de los apristas en Chile (1922- 1945). Santiago de Chile, Biblioteca Nacional de Chile, Centro de Investigaciones Diego Barros Arana, 2021, 281 p.

8 pages, 4 figures and 2 tables. ; [Background] The gene doublesex (dsx) is at the bottom of the sex determination genetic cascade and is transcribed in both sexes, but gives rise to two different proteins, DsxF and DsxM, which impose female and male sexual development respectively via the sex-specific regulation of the so-called sexual cyto-differentiation genes. The present manuscript addressed the question about the functional conservation of the tephritid Anastrepha DsxF and DsxM proteins to direct the sexual development in Drosophila (Drosophilidae). ; [Methodology] To express these proteins in Drosophila, the GAL4-UAS system was used. The effect of these proteins was monitored in the sexually dimorphic regions of the fly: the foreleg basitarsus, the 5th, 6th and 7th tergites, and the external terminalia. In addition, we analysed the effect of Anastrepha DsxF and DsxM proteins on the regulation of Drosophila yolk protein genes, which are expressed in the fat body of adult females under the control of dsx. ; Conclusions The Anastrepha DsxF and DsxM proteins transformed doublesex intersexual Drosophila flies into females and males respectively, though this transformation was incomplete and the extent of their influence varied in the different sexually dimorphic regions of the adult fly. The Anastrepha DsxF and DsxM proteins also behaved as activators and repressors, respectively, of the Drosophila yolk protein genes, as do the DsxF and DsxM proteins of Drosophila itself. Finally, the Anastrepha DsxF and DsxM proteins were found to counteract the functions of Drosophila DsxM and DsxF respectively, reflecting the normal behaviour of the latter proteins towards one another. Collectively, these results indicate that the Anastrepha DsxF and DsxM proteins show conserved female and male sex-determination function respectively in Drosophila, though it appears that they cannot fully substitute the latter's own Dsx proteins. This incomplete function might be partly due to a reduced capacity of the Anastrepha Dsx proteins to completely control the Drosophila sexual cyto-differentiation genes, a consequence of the accumulation of divergence between these species resulting in the formation of different co-adapted complexes between the Dsx proteins and their target genes. ; This work was financed by grant BFU2005-03000 awarded to L. Sa´nchez by the D.G.I.C.Y.T. (Spanish Government). ; Peer reviewed

14 p.-8 fig.-1 tab. ; Plant tolerance to freezing temperatures is governed by endogenous components and environmental factors. Exposure to low non-freezing temperatures is a key factor in the induction of freezing tolerance in the process called cold acclimation. The role of nitric oxide (NO) in cold acclimation was explored in Arabidopsis using triple nia1nia2noa1-2 mutants that are impaired in the nitrate-dependent and nitrate-independent pathways of NO production, and are thus NO deficient. Here, we demonstrate that cold-induced NO accumulation is required to promote the full cold acclimation response through C-repeat Binding Factor (CBF)-dependent gene expression, as well as the CBF-independent expression of other cold-responsive genes such as Oxidation-Related Zinc Finger 2 (ZF/OZF2). NO deficiency also altered abscisic acid perception and signaling and the cold-induced production of anthocyanins, which are additional factors involved in cold acclimation. ; This work was supported by grants from MINECO of Spain Government and FEDER EU funds [BIO2014-56067-P, BIO2017-82945-P to JL and BIO2016-79187-R to JS]. ; Peer reviewed

59 p.-8 fig. Título del preprint:The gene doublesex of dipteran Sciara does not follow the expression pattern observed in insects. ; The gene doublesex, which is placed at the bottom of the sex determination gene cascade, plays the ultimate discriminatory role for sex determination in insects. In all insects where this gene has been characterized, the dsx pre-mRNA follows a sex-specific splicing pattern producing male- and female-specific mRNAs, encoding the male-DSXM and female-DSXF proteins,which determine male and female development, respectively. The present paper reports the isolation and characterization of the gene doublesex of dipteran Sciara insects. The Sciara doublesex gene is constitutively transcribed during development and adult life of males and females. Sciara had no sex-specific doublesex mRNAs but the same transcripts, produced by alternative splicing of its primary transcript, were present in both sexes, although their relative abundance is sex-specific. However, only the female DSXF protein, but not the male DSXM protein, was produced at similar amounts in both sexes. An analysis of the expression of female and male Sciara DSX proteins in Drosophila showed that these proteins conserved female and male function, respectively, on the control of Drosophila yolk-protein genes. The molecular evolution of gene doublesex of all insects where this gene has been characterized revealed that Sciara doublesex displays a considerable degree of divergence with respect to the rest of dipterans, as suggested by its basal position within the doublesex phylogeny, its gene organization and its splicing pattern. It is proposed that if the gene doublesex were needed for Sciara sex determination, this gene would not play the ultimate discriminatory role for sex determination performed in insects. ; L Sánchez had financial support (BFU2005-03000 and BFU2008-00474) from the Spanish government during the time the group was doing the work presented in this manuscript. However, he had to close his laboratory —with the consequent disappearance of the group— because his grant was not renewed it due to the economical crisis in Spain. L Sánchez thanks very much to JL Barbero for permitting us to finish this work in his laboratory and sponsored by his grant. ; No