Biology subjects

Torres, A.

Publications and source records attributed to Torres, A..

5 recordsLinked to original sources

bioRxiv2018

Assessing mitochondrial function in angiosperms with highly divergent mitochondrial genomes

Angiosperm mitochondrial (mt) genes are generally slow-evolving, but multiple lineages have undergone dramatic accelerations in rates of nucleotide substitution and extreme changes in mt genome structure. While molecular evolution in these lineages has been investigated, very little is known about their mt function. Here, we develop a new protocol to characterize respiration in isolated plant mitochondria and apply it to species of Silene with mt genomes that are rapidly evolving, highly fragmented, and exceptionally large ([~]11 Mbp). This protocol, complemented with traditional measures of plant fitness, cytochrome c oxidase activity assays, and fluorescence microscopy, was used to characterize inter-and intraspecific variation in mt function. Contributions of the individual \"classic\" OXPHOS complexes, the alternative oxidase, and external NADH dehydrogenases to overall mt respiratory flux were found to be similar to previously studied angiosperms with more typical mt genomes. Some differences in mt function could be explained by inter-and intraspecific variation, possibly due to local adaptation or environmental effects. Although this study suggests that these Silene species with peculiar mt genomes still show relatively normal mt function, future experiments utilizing the protocol developed here can explore such questions in a more detailed and comparative framework.

plant biology↗

bioRxiv2017

Lymphopenic community acquired pneumonia, an unnoticed phenotype associated to mortality in non immuno-suppressed patients: a retrospective cohort study

BackgroundThe role of neutrophil and lymphocyte counts as predictors of prognosis in Community Acquired Pneumonia (CAP) has not been appropriately studied.\n\nMethodsThis was a retrospective study to evaluate by multivariate regression analysis, the association between neutrophil and lymphocyte counts with mortality at 30-days post discharge in two large cohorts of hospitalized patients with CAP and no prior immunosupression: a multicentric with 1550 patients recruited at 14 hospitals in Spain and a unicentric with 2840 patients recruited at the Hospital Clinic-Barcelona.\n\nFindingsThe unicentric cohort accounted with a higher proportion of critically ill patients: 586 (20{middle dot}6%) vs 131 (8{middle dot}5%) and non survivors 245 (8{middle dot}6%) vs 74 (4{middle dot}8%). Lymphopenia (< 1000 lymphocytes/mm3) was present in the 52{middle dot}8% of the patients in both cohorts. A sub-group of lymphopenic patients, those with lymphocyte counts below decil 3 (677 lymphocytes/mm3 in the multicentric cohort and 651 lymphocytes/mm3 in the unicentric one), showed > 2-fold increase in the risk of mortality, independently of the CURB-65 score, critical illness and receiving an appropriated antibiotic treatment: (OR [CI95%], p) (2{middle dot}18 [1{middle dot}21- 3{middle dot}92], 0{middle dot}009) and (2{middle dot}33 [1{middle dot}61-3{middle dot}33], <0{middle dot}001) respectively. Neutrophil counts were not associated with mortality risk.\n\nInterpretationLymphopenia is present in a half of the patients with CAP needing of hospitalization, in absence of antecendents of immunosupression. Lymphopenic CAP with lymphocyte counts < 664 lymphocytes/mm3 constitutes a particular immunological phenotype of the disease which is associated to an increased risk of mortality.\n\nFundingCibeRes, 2009 Support to Research Groups of Catalonia 911, IDIBAPS, SEPAR, SVN

immunology↗

bioRxiv2017

Characterization Of Beta Tubulin Isotypes During Foam Cell Formation

Foam cells contribute to the development of a cardiovascular condition called atherosclerosis. They arise when monocytes become engorged and lipid-laden after exposure to native low-density lipoproteins (Falk, 2006). It is assumed that the cytoskeleton is responsible for the morphological changes observed during foam cell formation. Beta tubulin and alpha tubulin are proteins that dimerize and polymerize to form microtubules, which are an important component of the cytoskeleton (Joshi, 1998). Little is known regarding the changes in cytoskeletal composition, particularly that of beta tubulins, throughout foam cell induction. The purpose of this study was to elucidate the expression patterns of beta tubulin isotypes 1-4 in human THP-1 monocytes throughout foam cell formation and to determine what relationship exists between beta tubulin expression and foam cell lipid aggregation. Levels of beta tubulin 1-4 were measured by western blot and immunofluorescence throughout the stages of foam cell differentiation, and beta tubulin isotypes were manipulated by siRNA to determine the effects of diminished beta tubulin expression on foam cell formation. Regardless of isotype, beta tubulin was always present in the highest amounts in monocytes. Levels of beta tubulin-1 and -4 were significantly decreased in macrophage and foam cells relative to monocytes (p < 0.0079, p < 0.0208, respectively). Beta 3 levels also exhibited a decrease. Beta 2 levels remained low regardless of differentiation stage. The distribution of beta tubulin 1 was shown to be more spindle-like (stretching across cells), compared to beta tubulins 2, 3, and 4, which exhibited a more \"clumped,\" less interconnected arrangement. When expression of beta tubulin isotypes 1, 3, and 4 were reduced in monocytes, resulting foam cells appeared to have more lipid aggregates and were significantly larger (p<0.0001) when compared to the size of foam cells without siRNA following treatment with PMA + LDL. In conclusion, the distribution of beta tubulins 1, 3, and 4 changes throughout the stages of foam cell induction, and manipulation of beta tubulins altered foam cell formation. Unexpectedly, the silencing or decreasing of beta tubulin enhanced lipid aggregation. Information concerning how beta tubulin expression can effect foam cell formation may offer insight into how to reduce plaque formation in patients with atherosclerosis.

cell biology↗

bioRxiv2017

An efficient FLP-based toolkit for spatiotemporal control of gene expression in Caenorhabditis elegans

Site-specific recombinases are potent tools to regulate gene expression. In particular, the Cre and FLP enzymes are widely used to either activate or inactivate genes in a precise spatiotemporal manner. Both recombinases work efficiently in the popular model organism Caenorhabditis elegans but their use in this nematode is still only sporadic. To increase the utility of the FLP system in C. elegans we have generated a series of single-copy transgenic strains that stably express an optimized version of FLP in specific tissues or by heat induction. We show that recombination efficiencies reach 100 percent in several cell types, such as muscles, intestine and serotonin producing neurons. Moreover, we demonstrate that most promoters drive recombination exclusively in the expected tissues. As examples of the potentials of the FLP lines we describe novel tools for induced cell ablation by expression of the PEEL-1 toxin and a versatile FLP-out cassette for generation of GFP-tagged conditional knockout alleles. Together with other recombinase-based reagents created by the C. elegans community this toolkit increases the possibilities for detailed analyses of specific biological processes at developmental stages inside intact animals.

genetics↗

bioRxiv2016

Compromised External Validity: Federally Produced Cannabis Does Not Reflect Legal Markets

As the most widely used illicit drug, the basis of the fastest growing major industry in the US, and as a source of numerous under-studied psychoactive compounds, understanding the psychological and physiological effects of Cannabis is essential. The National Institute on Drug Abuse (NIDA) is designated as the sole legal producer of Cannabis for use in US research studies. We sought to compare the chemical profiles of Cannabis varieties that are available to consumers in states that have state-legalized use versus what is available to researchers interested in studying the plant and its effects. Our results demonstrate that the federally produced Cannabis has significantly less variety and lower concentrations of cannabinoids. Current research, which has focused on material that is far less diverse and less potent than that used by the public, limits our understanding of the plants chemical, biological, psychological, medical, and pharmacological properties. Investigation is urgently needed on the diverse forms of Cannabis used by the public in state-legal markets.

plant biology↗