Lack of in vitro and in vivo effects of lipopolysaccharide on porcine circovirus type 2 infection

Porcine circovirus type 2 (PCV2) is the causative agent of postweaning multisystemic wasting syndrome (PMWS). The presence of immunostimulating factors or concurrent infections seems to be crucial for PMWS development. Lipopolysaccharide (LPS) is a potent immunological activator and has recently been suggested to enhance PCV2 replication in vitro. This study was designed to evaluate the effects of different LPS products on PCV2 in vitro replication of pulmonary macrophages (PMs), and on the potential ability to trigger PMWS in cesarean-derived, colostrum-deprived (CDCD) PCV2-inoculated piglets. In vitro studies using two different PCV2 isolates (Stoon-1010 and 1452/3) showed the presence of PCV2 antigen within the cytoplasm to a variable degree; PCV2 Stoon-1010 was barely detectable (

Expression of Toll-Like Receptors 2 and 4 is Upregulated During Hospital Admission in Traumatic Patients:Lack of Correlation with Blunted Innate Immune Responses

Background: There are reports with conflicting results on the expression of toll-like receptors (TLRs) in trauma patients. In addition, these studies analyzed TLR expression only at patients hospital admission but not later when complications usually arise. Objectives: To analyze the surface expression of TLR2 and TLR4 on circulating monocytes from trauma patients during the hospitalization period and to correlate this with cytokine production after stimulation with TLR2 and TLR4 agonists. The phagocytic capacity of monocytes was analyzed at the same time points of TLR expression analysis; to correlate these molecular findings with the presence or absence of infections. Methods: Prospective and observational study from June 2005 to June 2007. In all analysis, a control group composed of healthy subjects was included. Results: We studied 70 trauma patients admitted to the intensive care unit (ICU) of a tertiary hospital, and 30 healthy volunteers. Blood samples were collected at hospital admission, on day 7 and 14. Forty-four patients (63%) developed at least one episode of infection. Monocytes from trauma patients expressed higher levels of TLR2 and TLR4 than monocytes from control subjects at all time points. Expression of TLR2 and TLR4 in monocytes from those patients who developed any infection was significantly lower than in those patients without infection but still significantly higher than in control subjects. Cellular responses to TLR4 agonist were impaired. Monocytes from traumatic patients phagocytosized less efficiently than monocytes from control subjects. Conclusions: These results indicate that trauma patients present a dysregulation of the innate immune system that persists during the first 14 days after hospital admission. Copyright © 2010 by Lippincott Williams & Wilkins.

A computational study of the mechanism of CO oxidation by a ceria supported surface rhodium oxide layer

A mechanism of CO oxidation by a thin surface oxide of Rh supported on ceria is proposed: CO is oxidized by the Rh-oxide film, which is subsequently reoxidized by a ceria surface O atom. The proposed mechanism is supported by in situ Raman spectroscopic investigations.

Investigation of the mechanism of repression of rRNA synthesis by an anticancer drug

Ribosome biogenesis is a fundamental cellular process which is tightly regulated in normal cells. A number of tumour suppressors and oncogenes could affect the production of ribosomes at different levels and an upregulation could lead to increased protein biosynthesis which is one of the characteristic features of all cancer cells. Ribosome biogenesis is a very complex process which requires coordinated transcription by all three nucleolar polymerases and the first event in this process is synthesis of ribosomal RNA (rRNA) by RNA Polymerase I (Pol I). Importantly, recent data has pictured rRNA transcription as a key regulator of whole ribosome biogenesis and therefore makes it a valid and very attractive target for anticancer therapy, as well as a perspective biomarker. However, at the moment there is only one known specific inhibitor of Pol I transcription (at stage one of clinical trials) and this makes it very difficult for the development of drugs which would target rRNA transcription and consequently ribosome biogenesis. We have recently discovered that antitumor alkaloid ellipticine (isolated in 1959 from the plant species Ochrosia) is a potent inhibitor of Pol I transcription (both in vitro and in vivo). Ellipticine and its derivatives are known as efficient topoisomerase II inhibitors and inhibitors of some kinases, however we have shown that these inhibitory activities and the ability of ellipticine to repress Pol I activity are unrelated. Moreover, our preliminary data suggests that ellipticine specifically targets Pol I transcription and it has no effect on transcription by Pol II and Pol III at the same time scale. The possible mechanisms of inhibition of Pol I transcription by ellipticines will be discussed.

Lack of genetic structure and evidence for long-distance dispersal in ash (Fraxinus excelsior) populations under threat from an emergent fungal pathogen: implications for restorative planting

Genetic analysis on populations of European ash (Fraxinus excelsior) throughout Ireland was carried out to determine the levels and patterns of genetic diversity in naturally seeded trees in ash woodlands and hedgerows, with the aim of informing conservation and replanting strategies in the face of potential loss of trees as a result of ash dieback. Samples from 33 sites across Northern Ireland and three sites in the Republic of Ireland were genotyped for eight nuclear and ten chloroplast microsatellites. Levels of diversity were high (mean A R = 10.53; mean H O = 0.709; mean H E = 0.765) and were similar to those in Great Britain and continental Europe, whilst levels of population genetic differentiation based on nuclear microsatellites were extremely low (Φ ST = 0.0131). Levels of inbreeding (mean F IS = 0.067) were significantly lower than those reported for populations from Great Britain. Fine-scale analysis of seed dispersal indicated potential for dispersal over hundreds of metres. Our results suggest that ash woodlands across Ireland could be treated as a single management unit, and thus native material from anywhere in Ireland could be used as a source for replanting. In addition, high potential for dispersal has implications for recolonization processes post-ash dieback (Chalara fraxinea) infection, and could aid in our assessment of the capacity of ash to shift its range in response to global climate change.

Wireless electrochemical modification of catalytic activity on a mixed protonic-electronic conductor

A novel approach to electrochemical modification of catalytic activity using a wireless configuration has been undertaken. This paper presents preliminary results on the modification of a platinum catalyst film supported on a pellet of Sr_0.97Ce_0.9Yb_0.1O_3-δ (SCYb), considered to be a mixed protonic-electronic conductor under reducing conditions. The wireless configuration utilises the mixed ionic and electronic conductivity of the supporting membrane to supply an ionic promoting species to the catalyst surface. Control of the flux of this species is achieved by adjusting the effective hydrogen chemical potential difference across the membrane in a dual-chamber reactor with one chamber acting as the "reaction side" and the other as the "sweep side". The reaction rate can be promoted by up to a factor of 1.6, for temperatures around 500 °C and low reactant concentrations, when hydrogen is introduced on the sweep side of the membrane reactor. The use of helium, moist helium and oxygen in helium as sweep gases did not modify the reaction rate. © 2007 Elsevier B.V. All rights reserved.

Progress and the Lack of Progress in Addressing Infant Health and Infant Health Inequalities in Ireland during the 20th Century

There is a growing literature which documents the importance of early life environment for outcomes across the life cycle. Research, including studies based on Irish data, demonstrates that those who experience better childhood conditions go on to be wealthier and healthier adults. Therefore, inequalities at birth and in childhood shape inequality in wellbeing in later life, and the historical evolution of the mortality and morbidity of children born in Ireland is important for understanding the current status of the Irish population. In this paper, I describe these patterns by reviewing the existing literature on infant health in Ireland over the course of the 20th century. Up to the 1950s, infant mortality in Ireland (both North and South) was substantially higher than in other developed countries, with a large penalty for those born in urban areas. The subsequent reduction in this penalty, and the sustained decline in infant death rates, occurred later than would be expected from the experience in other contexts. Using records from the Rotunda Lying-in Hospital in Dublin, I discuss sources of disparities in stillbirth in the early 1900s. Despite impressive improvements in death rates since that time, a comparison with those born at the end of the century reveals that Irish children continue to be born unequal. Evidence from studies which track people across the life course, for example research on the returns to birthweight, suggests that the economic cost of this early life inequality is substantial.

Lack of Association Between Haptoglobin Phenotype and Cystic Fibrosis Outcomes

Haptoglobin (Hp), a heme-Iron chelator, has different isoforms which are associated with variable tendency toward infections: Hp 1-1, Hp 2-1, and Hp 2-2. Cystic fibrosis (CF) outcomes are variable and influenced by genetic and environmental factors. The aim of this study was to determine whether Hp phenotype influenced disease severity in CF. One hundred forty-two CF patients from two centers were analyzed for Haptoglobin phenotype using gel electrophoresis of hemoglobin enriched serum. Clinical and microbiological data including bacterial colonization status, lung function, presence of CF-related diabetes and liver disease, rate of exacerbation, and mortality were compared between Hp phenotype groups. We found a trend toward less mucoid PA among Hp 2-2 (20.4 %) compared with Hp 1-1 and Hp 2-1 individuals (33.3 %), p = 0.317. Hp 2-2 individuals also had less antibiotic courses, and lower inflammatory markers without statistical significance. Haptoglobin phenotype is unlikely to be an important modifier of CF phenotype.

Subdivision of the bacterioferritin comigratory protein family of bacterial peroxiredoxins based on catalytic activity

Peroxiredoxins are ubiquitous proteins that catalyze the reduction of hydroperoxides, thus conferring resistance to oxidative stress. Using high-resolution mass spectrometry, we recently reclassified one such peroxiredoxin, bacterioferritin comigratory protein (BCP) of Escherichia coli, as an atypical 2-Cys peroxiredoxin that functions through the formation of an intramolecular disulfide bond between the active and resolving cysteine. An engineered E. coli BCP, which lacked the resolving cysteine, retained enzyme activity through a novel catalytic pathway. Unlike the active cysteine, the resolving cysteine of BCP peroxiredoxins is not conserved across all members of the family. To clarify the catalytic mechanism of native BCP enzymes that lack the resolving cysteine, we have investigated the BCP homologue of Burkholderia cenocepacia. We demonstrate that the B. cenocepacia BCP (BcBCP) homologue functions through a 1-Cys catalytic pathway. During catalysis, BcBCP can utilize thioredoxin as a reductant for the sulfenic acid intermediate. However, significantly higher peroxidase activity is observed utilizing glutathione as a resolving cysteine and glutaredoxin as a redox partner. Introduction of a resolving cysteine into BcBCP changes the activity from a 1-Cys pathway to an atypical 2-Cys pathway, analogous to the E. coli enzyme. In contrast to the native B. cenocepacia enzyme, thioredoxin is the preferred redox partner for this atypical 2-Cys variant. BCP-deficient B. cenocepacia exhibit a growth-phase-dependent hypersensitivity to oxidative killing. On the basis of sequence alignments, we believe that BcBCP described herein is representative of the major class of bacterial BCP peroxiredoxins. To our knowledge, this is the first detailed characterization of their catalytic activity. These studies support the subdivision of the BCP family of peroxiredoxins into two classes based on their catalytic activity.

Phosphorylation Mechanism of Phosphomevalonate Kinase: Implications for Rational Engineering of Isoprenoid Biosynthetic Pathway Enzymes

Mevalonate pathway is of important clinical, pharmaceutical and biotechnological relevance. However, lack of the understanding of the phosphorylation mechanism of the kinases in this pathway has limited rationally engineering the kinases in industry. Here the phosphorylation reaction mechanism of a representative kinase in the mevalonate pathway, phosphomevalonate kinase, was studied by using molecular dynamics and hybrid QM/MM methods. We find that a conserved residue (Ser106) is reorientated to anchor ATP via a stable H-bond interaction. In addition, Ser213 located on the α-helix at the catalytic site is repositioned to further approach the substrate, facilitating the proton transfer during the phosphorylation. Furthermore, we elucidate that Lys101 functions to neutralize the negative charge developed at the β-, γ-bridging oxygen atom of ATP during phosphoryl transfer. We demonstrate that the dissociative catalytic reaction occurs via a direct phosphorylation pathway. This is the first study on the phosphorylation mechanism of a mevalonate pathway kinase. The elucidation of the catalytic mechanism not only sheds light on the common catalytic mechanism of GHMP kinase superfamily, but also provides the structural basis for engineering the mevalonate pathway kinases to further exploit their applications in the production of a wide range of fine chemicals such as biofuels or pharmaceuticals.