Nobel de Química 2009: estructura atómica de la maquinaria celular para sintetizar proteínas

The 2009 Nobel Prize in Chemistry has been awarded to Venkatraman Ramakrishnan (MRC Laboratory of Molecular Biology, United Kingdom), Thomas Steitz (Yale University, United States) and Ada Yonath (Weizmann Institute of Science, Israel) for their studies in the structure and function of the ribosome, a macromolecular machine that carries out protein synthesis within the cell. The scientists, in an incredible tour de force that took over twenty years, applied X-ray crystallography in order to determine the atomic structure of this large macromolecular complex, alone and in association with the major components in the protein synthesis process. The resulting models have been essential to understand the mechanisms underlying this process, in particular how the ribosome is able to decode messenger RNA (which carries the genetic information stored in DNA), how peptide bond catalysis proceeds, and the way in which several antibiotics protect us from bacterial infections.El Premio Nobel de Química de 2009 ha sido otorgado a Venkatraman Ramakrishnan (MRC Laboratory of Molecular Biology, Reino Unido), Thomas Steitz (Yale University, Estados Unidos) y Ada Yonath (Weizmann Institute of Science, Israel) por sus estudios sobre la estructura y función del ribosoma, la máquina macromolecular que lleva a cabo la síntesis de proteínas dentro de la célula. Los científicos, en un extraordinario esfuerzo de más de veinte años, aplicaron la cristalografía de rayos X para determinar la estructura atómica de este enorme complejo macromolecular, de forma aislada y en asociación con los principales componentes que intervienen en el proceso de síntesis proteica. Los modelos resultantes han sido esenciales para entender los mecanismos que subyacen a dicho proceso, en particular cómo el ribosoma es capaz de descifrar el ARN de mensajero (que porta la información genética contenida en el ADN), cómo procede la catálisis del enlace peptídico, y el modo en que varios antibióticos nos defienden de las infecciones bacterianas

Ofloxacin-like antibiotics inhibit pneumococcal cell wall-degrading virulence factors

The search for new drugs against Streptococcus pneumoniae (pneumococcus) is driven by the 1.5 million deaths it causes annually. Choline-binding proteins attach to the pneumococcal cell wall through domains that recognize choline moieties, and their involvement in pneumococcal virulence makes them potential targets for drug development. We have defined chemical criteria involved in the docking of small molecules from a three-dimensional structural library to the major pneumococcal autolysin (LytA) choline binding domain. These criteria were used to identify compounds that could interfere with the attachment of this protein to the cell wall, and several quinolones that fit this framework were found to inhibit the cell wall-degrading activity of LytA. Furthermore, these compounds produced similar effects on other enzymes with different catalytic activities but that contained a similar choline binding domain; that is, autolysin (LytC) and the phage lytic enzyme (Cpl-1). Finally, we resolved the crystal structure of the complex between the choline binding domain of LytA and ofloxacin at a resolution of 2.6 Å. These data constitute an important launch pad from which effective drugs to combat pneumococcal infections can be developed. © 2005 by The American Society for Biochemistry and Molecular Biology, Inc.This work was supported in part by Ministerio de Educación y Ciencia (Spain) Grants BIO2001-1724 and BMC2003-00074. The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore be hereby marked “advertisement” in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.Peer Reviewe

Human-Robot Cooperation for Surface Repair Combining Automatic and Manual Modes

This article develops a human-robot cooperation to carry out treatments such as sanding, polishing, etc. on the surface of a known rigid object. For this purpose, a vision system is considered to get the object location to ensure not only the perpendicularity of the robot tool to the object surface but also a smooth approach of the tool to the surface. In order to add flexibility, the proposal includes the simultaneous combination of automatic and manual modes of operation. Thus, the human user can guide the robot tool to treat arbitrary areas (manual mode) and, when the operator releases the tool, the robot goes into the automatic mode to treat prior established areas. The method uses a task prioritization framework and three types of controllers: an admittance controller for the tool guidance; a hybrid controller to modify the tool orientation and, in the automatic mode, the tool position; and a sliding mode controller to limit the velocity at which the tool approaches the object surface. The applicability and efficacy of the proposed method is demonstrated experimentally using a conventional 6R robot arm

Trans regulation in the Ultrabithorax gene of Drosophila: alterations in the promoter enhance transvection

PMCID: PMC556824We report a genetic and molecular study of UbxMX6 and Ubx195rx1, two mutations in the Ultrabithorax (Ubx) locus which appear to have a strong effect on the activity of the homologous Ubx gene. These mutations show the characteristic embryonic and adult phenotypes of Ubx null alleles, and also fail to produce any detectable Ubx product. Yet, genetic and phenotypic analyses involving a large number of trans heterozygous combinations of UbxMX6 and Ubx195rx1 with different classes of Ubx mutations, indicate that they hyperactivate the homologous gene. This effect is induced on wildtype or mutant forms of Ubx, provided that the pairing in the bithorax region is normal, i.e. these mutations have a strong positive effect on transvection. We also show that, unlike all the other known cases of transvection in Ubx, this is not zeste-dependent. Southern analyses indicate that UbxMX6 is a 3.4 kb deletion, and Ubx195rx1 is an approximately 11 kb insertion of foreign DNA, both in the promoter region. We speculate that the region altered in the mutations may have a wildtype function to ensure cis-autonomy of the regulation of Ubx transcription.This work was supported by grants from the DGICYT and the Fundación Ramón Areces.Peer reviewe

Cardiovascular disease in immune-mediated inflammatory diseases: a cross-sectional analysis of 6 cohorts

Observational study[Abstract] To analyze in several immune-mediated inflammatory diseases (IMIDs) the influence of demographic and clinical-related variables on the prevalence of cardiovascular disease (CVD), and compare their standardized prevalences.Cross-sectional study, including consecutive patients diagnosed with rheumatoid arthritis, psoriatic arthritis, psoriasis, systemic lupus erythematosus, Crohn disease, or ulcerative colitis, from rheumatology, gastroenterology, and dermatology tertiary care outpatient clinics located throughout Spain, between 2007 and 2010. Our main outcome was defined as previous diagnosis of angina, myocardial infarction, peripheral vascular disease, and/or stroke. Bivariate and multivariate logistic and mixed-effects logistic regression models were performed for each condition and the overall cohort, respectively. Standardized prevalences (in subjects per 100 patients, with 95% confidence intervals) were calculated using marginal analysis.We included 9951 patients. For each IMID, traditional cardiovascular risk factors had a different contribution to CVD. Overall, older age, longer disease duration, presence of traditional cardiovascular risk factors, and male sex were independently associated with a higher CVD prevalence. After adjusting for demographic and traditional cardiovascular risk factors, systemic lupus erythematosus exhibited the highest CVD standardized prevalence, followed by rheumatoid arthritis, psoriasis, Crohn disease, psoriatic arthritis, and ulcerative colitis (4.5 [95% confidence interval (CI): 2.2, 6.8], 1.3 [95% CI: 0.8, 1.8], 0.9 [95% CI: 0.5, 1.2], 0.8 [95% CI: 0.2, 1.3], 0.6 [95% CI: 0.2, 1.0], and 0.5 [95% CI: 0.1, 0.8], respectively).Systemic lupus erythematosus, rheumatoid arthritis, and psoriasis are associated with higher prevalence of CVD compared with other IMIDs. Specific prevention programs should be established in subjects affected with these conditions to prevent CVD

Genetic variation associated with cardiovascular risk in autoimmune diseases

Autoimmune diseases have a higher prevalence of cardiovascular events compared to the general population. The objective of this study was to investigate the genetic basis of cardiovascular disease (CVD) risk in autoimmunity. We analyzed genome-wide genotyping data from 6,485 patients from six autoimmune diseases that are associated with a high socio-economic impact. First, for each disease, we tested the association of established CVD risk loci. Second, we analyzed the association of autoimmune disease susceptibility loci with CVD. Finally, to identify genetic patterns associated with CVD risk, we applied the cross-phenotype meta-analysis approach (CPMA) on the genome-wide data. A total of 17 established CVD risk loci were significantly associated with CVD in the autoimmune patient cohorts. From these, four loci were found to have significantly different genetic effects across autoimmune diseases. Six autoimmune susceptibility loci were also found to be associated with CVD risk. Genome-wide CPMA analysis identified 10 genetic clusters strongly associated with CVD risk across all autoimmune diseases. Two of these clusters are highly enriched in pathways previously associated with autoimmune disease etiology (TNF? and IFN? cytokine pathways). The results of this study support the presence of specific genetic variation associated with the increase of CVD risk observed in autoimmunity

Cardiovascular disease in immune-mediated inflammatory diseases: A cross-sectional analysis of 6 cohorts

To analyze in several immune-mediated inflammatory diseases (IMIDs) the influence of demographic and clinical-related variables on the prevalence of cardiovascular disease (CVD), and compare their standardized prevalences.Cross-sectional study, including consecutive patients diagnosed with rheumatoid arthritis, psoriatic arthritis, psoriasis, systemic lupus erythematosus, Crohn disease, or ulcerative colitis, from rheumatology, gastroenterology, and dermatology tertiary care outpatient clinics located throughout Spain, between 2007 and 2010. Our main outcome was defined as previous diagnosis of angina, myocardial infarction, peripheral vascular disease, and/or stroke. Bivariate and multivariate logistic and mixed-effects logistic regression models were performed for each condition and the overall cohort, respectively. Standardized prevalences (in subjects per 100 patients, with 95% confidence intervals) were calculated using marginal analysis.We included 9951 patients. For each IMID, traditional cardiovascular risk factors had a different contribution to CVD. Overall, older age, longer disease duration, presence of traditional cardiovascular risk factors, and male sex were independently associated with a higher CVD prevalence. After adjusting for demographic and traditional cardiovascular risk factors, systemic lupus erythematosus exhibited the highest CVD standardized prevalence, followed by rheumatoid arthritis, psoriasis, Crohn disease, psoriatic arthritis, and ulcerative colitis (4.5 [95% confidence interval (CI): 2.2, 6.8], 1.3 [95% CI: 0.8, 1.8], 0.9 [95% CI: 0.5, 1.2], 0.8 [95% CI: 0.2, 1.3], 0.6 [95% CI: 0.2, 1.0], and 0.5 [95% CI: 0.1, 0.8], respectively).Systemic lupus erythematosus, rheumatoid arthritis, and psoriasis are associated with higher prevalence of CVD compared with other IMIDs. Specific prevention programs should be established in subjects affected with these conditions to prevent CVD

A cryptic variation in a member of the Ovate Family Proteins is underlying the melon fruit shape QTL fsqs8.1

Melon cultivars have a wide range of fruit morphologies. Quantitative trait loci (QTL) have been identifed underlying such diversity. This research focuses on the fruit shape QTL fsqs8.1, previously detected in a cross between the accession PI 124112 (CALC, producing elongated fruit) and the cultivar ‘Piel de Sapo’ (PS, producing oval fruit). The CALC fsqs8.1 allele induced round fruit shape, being responsible for the transgressive segregation for this trait observed in that population. In fact, the introgression line CALC8-1, carrying the fsqs8.1 locus from CALC into the PS genetic background, produced perfect round fruit. Following a map-based cloning approach, we found that the gene underlying fsqs8.1 is a member of the Ovate Family Proteins (OFP), CmOFP13, likely a homologue of AtOFP1 and SlOFP20 from Arabidopsis thaliana and tomato, respectively. The induction of the round shape was due to the higher expression of the CALC allele at the early ovary development stage. The fsqs8.1 locus showed an important structural variation, being CmOFP13 surrounded by two deletions in the CALC genome. The deletions are present at very low frequency in melon germplasm. Deletions and single nucleotide polymorphisms in the fsqs8.1 locus could not be not associated with variation in fruit shape among diferent melon accessions, what indicates that other genetic factors should be involved to induce the CALC fsqs8.1 allele efects. Therefore, fsqs8.1 is an example of a cryptic variation that alters gene expression, likely due to structural variation, resulting in phenotypic changes in melon fruit morphology.info:eu-repo/semantics/publishedVersio

The dynamic assembly of distinct RNA polymerase I complexes modulates rDNA transcription

Cell growth requires synthesis of ribosomal RNA by RNA polymerase I (Pol I). Binding of initiation factor Rrn3 activates Pol I, fostering recruitment to ribosomal DNA promoters. This fundamental process must be precisely regulated to satisfy cell needs at any time. We present in vivo evidence that, when growth is arrested by nutrient deprivation, cells induce rapid clearance of Pol I-Rrn3 complexes, followed by the assembly of inactive Pol I homodimers. This dual repressive mechanism reverts upon nutrient addition, thus restoring cell growth. Moreover, Pol I dimers also form after inhibition of either ribosome biogenesis or protein synthesis. Our mutational analysis, based on the electron cryomicroscopy structures of monomeric Pol I alone and in complex with Rrn3, underscores the central role of subunits A43 and A14 in the regulation of differential Pol I complexes assembly and subsequent promoter association.The project was supported by grant BFU2013-48374-P of the Spanish MINECO and by the Ramón Areces Foundation. O.G. held a research contract under the Ramón y Cajal program of the Spanish MINECO (RYC-2011-07967). IRB Barcelona is the recipient of a Severo Ochoa Award of Excellence from the Spanish MINECO.Peer reviewe