Enhanced vascular permeability facilitates entry of plasma HDL and promotes macrophage-reverse cholesterol transport from skin in mice

Reverse cholesterol transport (RCT) pathway from macrophage foam cells initiates when HDL particles cross the endothelium, enter the interstitial fluid, and induce cholesterol efflux from these cells. We injected [³H]cholesterol-loaded J774 macrophages into the dorsal skin of mice and measured the transfer of macrophage-derived [³H]cholesterol to feces [macrophage-RCT (m-RCT)]. Injection of histamine to the macrophage injection site increased locally vascular permeability, enhanced influx of intravenously administered HDL, and stimulated m-RCT from the histamine-treated site. The stimulatory effect of histamine on m-RCT was abolished by prior administration of histamine H1 receptor (H1R) antagonist pyrilamine, indicating that the histamine effect was H1R-dependent. Subcutaneous administration of two other vasoactive mediators, serotonin or bradykinin, and activation of skin mast cells to secrete histamine and other vasoactive compounds also stimulated m-RCT. None of the studied vasoactive mediators affected serum HDL levels or the cholesterol-releasing ability of J774 macrophages in culture, indicating that acceleration of m-RCT was solely due to increased availability of cholesterol acceptors in skin. We conclude that disruption of the endothelial barrier by vasoactive compounds enhances the passage of HDL into interstitial fluid and increases the rate of RCT from peripheral macrophage foam cells, which reveals a novel tissue cholesterol-regulating function of these compounds.     

Environmental assessment of black locust (<Emphasis Type="BoldItalic">Robinia pseudoacacia</Emphasis> L.)-based ethanol as potential transport fuel

Purpose  

Lignocellulosic ethanol has received special research interest, driven by concerns over high fuel prices, security of energy supplies, global climate change as well as the search of opportunities for rural economic development. A well-to-wheel analysis was conducted for ethanol obtained from black locust (Robinia pseudoacacia L.) by means of the life cycle assessment (LCA) methodology. This study assesses the environmental profile of using ethanol in mixtures E10 and E85 as transport fuel in comparison with conventional gasoline (CG). In addition, the best model of black locust cultivation was analysed under an environmental point of view.     

Synthesis and structural study of highly constrained hybrid cyclobutane-proline γ,γ-peptides

Two diastereomeric series of hybrid γ,γ-peptides derived from conveniently protected derivatives of (1R,2S)- and (1S,2R)-3-amino-2,2-dimethylcyclobutane-1-carboxylic acid and cis-4-amino-l-proline joined in alternation have efficiently been prepared through convergent synthesis. High-resolution NMR experiments show that these compounds present defined conformations in solution affording very compact structures as the result of intra and inter residue hydrogen-bonded ring formation. (R,S)-cyclobutane containing peptides adopt more twisted conformations than (S,R) diastereomers. In addition, all these γ-peptides have high tendency to aggregation providing vesicles of nanometric size, which were stable when allowed to stand for several days, as verified by transmission electron microscopy.     

AtNUFIP, an essential protein for plant development, reveals the impact of snoRNA gene organisation on the assembly of snoRNPs and rRNA methylation in Arabidopsis thaliana

In all eukaryotes, C/D small nucleolar ribonucleoproteins (C/D snoRNPs) are essential for methylation and processing of ribosomal RNAs. They consist of a box C/D small nucleolar RNA (C/D snoRNA) associated with four highly conserved nucleolar proteins. Recent data in HeLa cells and yeast have revealed that assembly of these snoRNPs is directed by NUFIP protein and other auxiliary factors. Nevertheless, the precise function and biological importance of NUFIP and the other assembly factors remains unknown. In plants, few studies have focused on RNA methylation and snoRNP biogenesis. Here, we identify and characterise the AtNUFIP gene that directs assembly of C/D snoRNP. To elucidate the function of AtNUFIP in planta, we characterized atnufip mutants. These mutants are viable but have severe developmental phenotypes. Northern blot analysis of snoRNA accumulation in atnufip mutants revealed a specific degradation of C/D snoRNAs and this situation is correlated with a reduction in rRNA methylation. Remarkably, the impact of AtNUFIP depends on the structure of snoRNA genes: it is essential for the accumulation of those C/D snoRNAs encoded by polycistronic genes, but not by monocistronic or tsnoRNA genes. We propose that AtNUFIP controls the kinetics of C/D snoRNP assembly on nascent precursors to overcome snoRNA degradation of aberrant RNPs. Finally, we show that AtNUFIP has broader RNP targets, controlling the accumulation of scaRNAs that direct methylation of spliceosomal snRNA in Cajal bodies.     

Thermogravimetry study of xylanase- and laccase/mediator-treated eucalyptus pulp fibres

Thermogravimetric analyses (TGA) was applied to study the effects of enzymatic bleaching of eucalyptus pulp with xylanase and a laccase-mediator system. The thermal degradation profile of the pulps was sensitive to the enzymatic treatments. Xylanase treatment produced an ordered and clean microfibril, whereas laccase oxidized surface cellulose chains and increased the amorphous (paracrystalline) cellulose content. In this case, pulp viscosity decreased from 972 to 859 mL/g and apparent pulp crystallinity calculated from TGA data decreased almost 50%. Alkaline extraction was necessary to recover pulp crystallinity and to remove oxidized lignin in the laccase-treated samples. TGA data allowed differentiating and quantifying crystalline and amorphous cellulose. This thermogravimetric approach is a simple method in order to monitor superficial changes in cellulosic microfibrils.     

Discovery of substituted phenyl urea derivatives as novel long-acting β2-adrenoreceptor agonists

The synthesis of diverse functionalized ureas in a semi-parallel fashion is described, as well as their β₁/β₂-adrenergic activities and the corresponding structure-activity relationship (SAR). We have focused on lipophilicity and duration of action, and we have discovered a strong correlation in this series of molecules. A quantitative structure-activity relationship (QSAR) analysis will be presented that quantifies this relationship.     

Annexin A6 is an organizer of membrane microdomains to regulate receptor localization and signalling

Annexin A6 (AnxA6) belongs to the conserved annexin protein family--a group of Ca(2+) -dependent membrane binding proteins. It is the largest of all annexin proteins and upon activation, binds to negatively charged phospholipids in the plasma membrane and endosomes. In addition, AnxA6 associates with cholesterol-rich membrane microdomains termed lipid rafts. Membrane cholesterol triggers Ca(2+) -independent translocation of AnxA6 to membranes and AnxA6 levels determine the number of caveolae, a form of specialized rafts at the cell surface. AnxA6 also has an F-actin binding domain and interacts with cytoskeleton components. Taken together, this suggests that AnxA6 has a scaffold function to link membrane microdomains with the organization of the cytoskeleton. Such a link facilitates AnxA6 to participate in plasma membrane repair and it would also impact on receptor signalling at the cell surface, growth factor, and lipoprotein receptor trafficking, Ca(2+) -channel activity and T cell activation. Hence, the regulation of cell surface receptors by AnxA6 may be facilitated by its unique structure that allows recruitment of interaction partners and simultaneously bridging specialized membrane domains with cortical actin surrounding activated receptors.     

The Rose Bengal Test in human brucellosis: a neglected test for the diagnosis of a neglected disease

Brucellosis is a highly contagious zoonosis affecting livestock and human beings. The human disease lacks pathognomonic symptoms and laboratory tests are essential for its diagnosis. However, most tests are difficult to implement in the areas and countries were brucellosis is endemic. Here, we compared the simple and cheap Rose Bengal Test (RBT) with serum agglutination, Coombs, competitive ELISA, Brucellacapt, lateral flow immunochromatography for IgM and IgG detection and immunoprecipitation with Brucella proteins. We tested 208 sera from patients with brucellosis proved by bacteriological isolation, 20 contacts with no brucellosis, and 1559 sera of persons with no recent contact or brucellosis symptoms. RBT was highly sensitive in acute and long evolution brucellosis cases and this related to its ability to detect IgM, IgG and IgA, to the absence of prozones, and to the agglutinating activity of blocking IgA at the pH of the test. RBT was also highly specific in the sera of persons with no contact with Brucella. No test in this study outperformed RBT, and none was fully satisfactory in distinguishing contacts from infected patients. When modified to test serum dilutions, a diagnostic titer >4 in RBT resulted in 87.4% sensitivity (infected patients) and 100% specificity (contacts). We discuss the limitations of serological tests in the diagnosis of human brucellosis, particularly in the more chronic forms, and conclude that simplicity and affordability of RBT make it close to the ideal test for small and understaffed hospitals and laboratories.     

Fragmentation of contaminant and endogenous DNA in ancient samples determined by shotgun sequencing; prospects for human palaeogenomics

BACKGROUND: Despite the successful retrieval of genomes from past remains, the prospects for human palaeogenomics remain unclear because of the difficulty of distinguishing contaminant from endogenous DNA sequences. Previous sequence data generated on high-throughput sequencing platforms indicate that fragmentation of ancient DNA sequences is a characteristic trait primarily arising due to depurination processes that create abasic sites leading to DNA breaks. METHODOLOGY/PRINCIPALS FINDINGS: To investigate whether this pattern is present in ancient remains from a temperate environment, we have 454-FLX pyrosequenced different samples dated between 5,500 and 49,000 years ago: a bone from an extinct goat (Myotragus balearicus) that was treated with a depurinating agent (bleach), an Iberian lynx bone not subjected to any treatment, a human Neolithic sample from Barcelona (Spain), and a Neandertal sample from the El Sidrón site (Asturias, Spain). The efficiency of retrieval of endogenous sequences is below 1% in all cases. We have used the non-human samples to identify human sequences (0.35 and 1.4%, respectively), that we positively know are contaminants. CONCLUSIONS: We observed that bleach treatment appears to create a depurination-associated fragmentation pattern in resulting contaminant sequences that is indistinguishable from previously described endogenous sequences. Furthermore, the nucleotide composition pattern observed in 5' and 3' ends of contaminant sequences is much more complex than the flat pattern previously described in some Neandertal contaminants. Although much research on samples with known contaminant histories is needed, our results suggest that endogenous and contaminant sequences cannot be distinguished by the fragmentation pattern alone.