Ensayo de formación y cuantificación de biopelículas mixtas de Candida albicans y Staphylococcus aureus

This study quantifies the production of single and mixed biofilms of Candida albicans and Staphylococcus aureus to determine if such mixed biofilms have synergistic effects. Assays were performed using polystyrene microtitre plates of 96 wells, metabolic activity was measured by the enzymatic reduction of a tetrazolium salt (XTT) and colorimetric changes were measured at 490 nm. Confocal scanning laser microscopy was used to visualise the biofilms of each microorganism and its growth kinetics. The highest levels of biofilm formation were observed in mixed biofilms, followed by those of Candida albicans only, with the lowest levels of biofilm formation being detected for Staphylococcus aureus; all together these results suggest a synergistic relationship between the tested microorganisms.     

The -2518 A/G polymorphism in the monocyte chemoattractant protein 1 gene is associated with the risk of developing systemic lupus erythematosus in Argentinean patients: a multicenter study

Systemic lupus erythematosus (SLE) is a systemic, autoimmune disorder. Monocyte chemoattractant protein 1 (MCP-1), a chemokine involved in the recruitment and migration of monocytes/macrophages, has been shown to be increased in the plasma of SLE patients. The aim of our study was to evaluate the possible association of the polymorphism -2518 of the MCP-1 gene with the risk of developing SLE, manifesting lupus nephritis (LN) and with other clinical features of SLE in an Argentinean population. A group of 171 SLE patients and 120 control subjects were examined. Genotypic and allelic frequencies of the MCP-1 -2518 A/G polymorphism showed significant differences between the SLE and the control groups (p=0.001 and p=0.01, respectively). However, the polymorphism showed no association with LN or with the other clinical variables studied. Our results suggest that the presence of the MCP-1 -2518 A/G polymorphism might be a risk factor for developing SLE in genetically predisposed individuals, but it does not seem to have a role in the evolution of the disease in the Argentinean population.     

Production of a monoclonal antibody by ascites, hollow fiber system, and transgenic plants for vaccine production using CB.Hep-1 mAb as a study case

Monoclonal antibody (mAb) production methods (ascites, in vitro technologies, transgenic animals, and dicot or monocot transgenic plants; moss, algae) have been improved since they were first developed in 1975. In this study, we illustrate a summary of a study case in which mice, a hollow fiber system, and tobacco transgenic plants were assessed for the production of mAb for vaccine manufacturing and vaccine production.     

The ArcB leucine zipper domain is required for proper ArcB signaling

The Arc two-component system modulates the expression of numerous genes in response to respiratory growth conditions. This system comprises ArcA as the response regulator and ArcB as the sensor kinase. ArcB is a tripartite histidine kinase whose activity is regulated by the oxidation of two cytosol-located redox-active cysteine residues that participate in intermolecular disulfide bond formation. Here, we report that the ArcB protein segment covering residues 70-121, fulfills the molecular characteristics of a leucine zipper containing coiled coil structure. Also, mutational analyses of this segment reveal three different phenotypical effects to be distributed along the coiled coil structure of ArcB, demonstrating that this motif is essential for proper ArcB signaling.     

Age-Dependent Changes in the Sphingolipid Composition of Mouse CD4+ T Cell Membranes and Immune Synapses Implicate Glucosylceramides in Age-Related T Cell Dysfunction

To determine whether changes in sphingolipid composition are associated with age-related immune dysfunction, we analyzed the core sphingolipidome (i.e., all of the metabolites through the first headgroup additions) of young and aged CD4⁺ T cells. Since sphingolipids influence the biophysical properties of membranes, we evaluated the compositions of immune synapse (IS) and non-IS fractions prepared by magnetic immuno-isolation. Broadly, increased amounts of sphingomyelins, dihydrosphingomyelins and ceramides were found in aged CD4⁺ T cells. After normalizing for total sphingolipid content, a statistically significant decrease in the molar fraction of glucosylceramides was evident in both the non-IS and IS fractions of aged T cells. This change was balanced by less dramatic increases in the molar fractions of sphingomyelins and dihydrosphingomyelins in aged CD4⁺ T cells. In vitro, the direct or enzymatic enhancement of ceramide levels decreased CD4⁺ T cell proliferation without regard for the age of the responding T cells. In contrast, the in vitro inhibition of glucosylceramidase preferentially increased the proliferation of aged CD4⁺ T cells. These results suggest that reductions in glucosylceramide abundance contribute to age-related impairments in CD4⁺ T cell function.     

An Overview of the Genetic Structure within the Italian Population from Genome-Wide Data

In spite of the common belief of Europe as reasonably homogeneous at genetic level, advances in high-throughput genotyping technology have resolved several gradients which define different geographical areas with good precision. When Northern and Southern European groups were considered separately, there were clear genetic distinctions. Intra-country genetic differences were also evident, especially in Finland and, to a lesser extent, within other European populations. Here, we present the first analysis using the 125,799 genome-wide Single Nucleotide Polymorphisms (SNPs) data of 1,014 Italians with wide geographical coverage. We showed by using Principal Component analysis and model-based individual ancestry analysis, that the current population of Sardinia can be clearly differentiated genetically from mainland Italy and Sicily, and that a certain degree of genetic differentiation is detectable within the current Italian peninsula population. Pair-wise F_ST statistics Northern and Southern Italy amounts approximately to 0.001 between, and around 0.002 between Northern Italy and Utah residents with Northern and Western European ancestry (CEU). The Italian population also revealed a fine genetic substructure underscoring by the genomic inflation (Sardinia vs. Northern Italy = 3.040 and Northern Italy vs. CEU = 1.427), warning against confounding effects of hidden relatedness and population substructure in association studies.     

Pristine Early Eocene Wood Buried Deeply in Kimberlite from Northern Canada

We report exceptional preservation of fossil wood buried deeply in a kimberlite pipe that intruded northwestern Canada’s Slave Province 53.3±0.6 million years ago (Ma), revealed during excavation of diamond source rock. The wood originated from forest surrounding the eruption zone and collapsed into the diatreme before resettling in volcaniclastic kimberlite to depths >300 m, where it was mummified in a sterile environment. Anatomy of the unpermineralized wood permits conclusive identification to the genus Metasequoia (Cupressaceae). The wood yields genuine cellulose and occluded amber, both of which have been characterized spectroscopically and isotopically. From cellulose δ¹⁸O and δ²H measurements, we infer that Early Eocene paleoclimates in the western Canadian subarctic were 12–17°C warmer and four times wetter than present. Canadian kimberlites offer Lagerstätte-quality preservation of wood from a region with limited alternate sources of paleobotanical information.