A novel K+ channel blocking toxin from Tityus discrepans scorpion venom

AbstractA novel toxin (TdK1) was purified from the venom of the scorpion Tityus discrepans, sequenced and functionally characterized. It contains 37 amino acid residues and blocks reversible the shakerB K+ channel expressed in SF9 cells with a Kd in the order of 280 nM. The proposed systematic nomenclature for this peptide is α-KTx4.3

Tc1, from Tityus cambridgei, is the first member of a new subfamily of scorpion toxin that blocks K+-channels

AbstractA new peptide, Tc1, containing only 23 amino acids closely packed by three disulfide bridges was isolated from the Amazonian scorpion Tityus cambridgei. It blocks reversibly the Shaker B K+-channels with a Kd of 65 nM and displaces binding of noxiustoxin to mouse brain synaptosome membranes. It is the shortest known peptide from scorpion venom that recognizes K+-channels and constitutes a new structural subfamily of toxin, classified as alphaKTx 13.1

Role of the gibberellin receptors GID1 during fruit-set in Arabidopsis

[EN] Gibberellins (GAs) play a critical role in fruit-set and fruit growth. Gibberellin is perceived by its nuclear receptors GA INSENSITIVE DWARF1s (GID1s), which then trigger degradation of downstream repressors DELLAs. To understand the role of the three GA receptor genes (GID1A, GID1B and GID1C) in Arabidopsis during fruit initiation, we have examined their temporal and spatial localization, in combination with analysis of mutant phenotypes. Distinct expression patterns are revealed for each GID1: GID1A is expressed throughout the whole pistil, while GID1B is expressed in ovules, and GID1C is expressed in valves. Functional study of gid1 mutant combinations confirms that GID1A plays a major role during fruit-set and growth, whereas GID1B and GID1C have specific roles in seed development and pod elongation, respectively. Therefore, in ovules, GA perception is mediated by GID1A and GID1B, while GID1A and GID1C are involved in GA perception in valves. To identify tissue-specific interactions between GID1s and DELLAs, we analyzed spatial expression patterns of four DELLA genes that have a role in fruit initiation (GAI, RGA, RGL1 and RGL2). Our data suggest that GID1A can interact with RGA and GAI in all tissues, whereas GID1C-RGL1 and GID1B-RGL2 interactions only occur in valves and ovules, respectively. These results uncover specific functions of each GID1-DELLA in the different GA-dependent processes that occur upon fruit-set. In addition, the distribution of GA receptors in valves along with lack of expression of GA biosynthesis genes in this tissue, strongly suggests transport of GAs from the developing seeds to promote fruit growth.We wish to thank Dr Masatoshi Nakajima (University of Tokyo, Japan) for providing the pGID1:GID1-GUS lines, and Dr Peter Hedden (Rothamsted Research, UK) for the pGA20ox:GA20ox-GUS lines. We also thank Ms C. Fuster and M. A. Argomaniz for technical assistance. This work has been supported by grants BIO2008-01039 and BIO2011-26302 from the Spanish Ministry of Science and Innovation and ACOMP/2010/079 and ACOMP/2011/287 from the Generalitat Valenciana for M. A. P.-A. and USDA grants 2010-65116-20460 and 2014-67013-21548 for T. P. S. C. G.-G. received a JAE PhD fellowship from the Spanish Council for Scientific Research (CSIC).Gallego Giraldo, C.; Hu, J.; Urbez Lagunas, C.; Gómez Jiménez, MD.; Sun, TP.; Perez Amador, MA. (2014). Role of the gibberellin receptors GID1 during fruit-set in Arabidopsis. Plant Journal. 79(6):1020-1032. doi:10.1111/tpj.12603S1020103279

Sistemas delta adaptativos con control digital en canales ruidosos

Peer ReviewedPostprint (published version

Aplicación del muestreo enfatizado a la evaluación de transmisiones digitales

The Importance Sampling Technique is a method for reducing the computational effort in Montecarlo simulations for obtaining the relative frequency of an event having a very low probability. While this method is well known in general Operations Research /1//2//3/ and Radar /4//5//6//7//8//9//10/, it has not been considered in digital communication problems. This paper aims to introduce the Importance Sampling concept in this communication context.Peer ReviewedPostprint (published version

Diversity of HLA Class I and Class II blocks and conserved extended haplotypes in Lacandon Mayans.

Here we studied HLA blocks and haplotypes in a group of 218 Lacandon Maya Native American using a high-resolution next generation sequencing (NGS) method. We assessed the genetic diversity of HLA class I and class II in this population, and determined the most probable ancestry of Lacandon Maya HLA class I and class II haplotypes. Importantly, this Native American group showed a high degree of both HLA homozygosity and linkage disequilibrium across the HLA region and also lower class II HLA allelic diversity than most previously reported populations (including other Native American groups). Distinctive alleles present in the Lacandon population include HLA-A*24:14 and HLA-B*40:08. Furthermore, in Lacandons we observed a high frequency of haplotypes containing the allele HLA-DRB1*04:11, a relatively frequent allele in comparison with other neighboring indigenous groups. The specific demographic history of the Lacandon population including inbreeding, as well as pathogen selection, may have elevated the frequencies of a small number of HLA class II alleles and DNA blocks. To assess the possible role of different selective pressures in determining Native American HLA diversity, we evaluated the relationship between genetic diversity at HLA-A, HLA-B and HLA-DRB1 and pathogen richness for a global dataset and for Native American populations alone. In keeping with previous studies of such relationships we included distance from Africa as a covariate. After correction for multiple comparisons we did not find any significant relationship between pathogen diversity and HLA genetic diversity (as measured by polymorphism information content) in either our global dataset or the Native American subset of the dataset. We found the expected negative relationship between genetic diversity and distance from Africa in the global dataset, but no relationship between HLA genetic diversity and distance from Africa when Native American populations were considered alone