A map of the class III region of the sheep major histocompatibilty complex

<p>Abstract</p> <p>Background</p> <p>The central, or class III, region of the major histocompatibility complex (MHC) is an important gene rich sub-region of the MHC of mammals and contains many loci implicated in disease processes and potential productivity traits. As a prelude to identifying MHC loci associated with productivity traits in sheep, we have used BAC and cosmid libraries of genomic DNA to generate a physical map of the sheep MHC class III region. This map will facilitate association studies and provide insights into the distribution of recombination events in this chromosomal segment.</p> <p>Results</p> <p>Twenty eight sheep genes were identified in 10 BAC clones which spanned approximately 700 kbp of a chromosomal region adjacent to the class I region of the sheep MHC and which therefore covers most, if not all, of the class III of the sheep MHC. The relative positions of 17 of these genes was established as well as two additional groups of genes for which the intragroup order was not known. Cosmid mapping permitted a more detailed mapping of the complement genes present in the class III and showed a local inversion (relative to humans) of one pair of the duplicated complement C4 and CYP21 loci. A panel of 26 single nucleotide polymorphisms (SNPs) was identified in 10 loci, covering ≈600 kbp of the mapped region.</p> <p>Conclusion</p> <p>This report provides a physical map covering ≈700 kbp of the class III of the sheep MHC together with a SNP panel which will facilitate disease and productivity association studies. The presence of a local inversion (relative to humans) of one pair of the duplicated C4 and CYP21 loci and a previously described dinucleotide tandem repeat locus (BfMs) has been located within an intron of the SK12VL gene.</p

The Effects of Mary Rose Conservation Treatment on Iron Oxidation Processes and Microbial Communities Contributing to Acid Production in Marine Archaeological Timbers

The Tudor warship the Mary Rose has reached an important transition point in her conservation. The 19 year long process of spraying with polyethylene glycol (PEG) has been completed (April 29th 2013) and the hull is air drying under tightly controlled conditions. Acidophilic bacteria capable of oxidising iron and sulfur have been previously identified and enriched from unpreserved timbers of the Mary Rose, demonstrating that biological pathways of iron and sulfur oxidization existed potentially in this wood, before preservation with PEG. This study was designed to establish if the recycled PEG spray system was a reservoir of microorganisms capable of iron and sulfur oxidization during preservation of the Mary Rose. Microbial enrichments derived from PEG impregnated biofilm collected from underneath the Mary Rose hull, were examined to better understand the processes of cycling of iron. X-ray absorption spectroscopy was utilised to demonstrate the biological contribution to production of sulfuric acid in the wood. Using molecular microbiological techniques to examine these enrichment cultures, PEG was found to mediate a shift in the microbial community from a co-culture of Stenotrophomonas and Brevunidimonas sp, to a co-culture of Stenotrophomonas and the iron oxidising Alicyclobacillus sp. Evidence is presented that PEG is not an inert substance in relation to the redox cycling of iron. This is the first demonstration that solutions of PEG used in the conservation of the Mary Rose are promoting the oxidation of ferrous iron in acidic solutions, in which spontaneous abiotic oxidation does not occur in water. Critically, these results suggest PEG mediated redox cycling of iron between valence states in solutions of 75% PEG 200 and 50% PEG 2000 (v/v) at pH 3.0, with serious implications for the future use of PEG as a conservation material of iron rich wooden archaeological artefacts

Variation in adult annual survival probability and remigration intervals of sea turtles

We analyzed a large dataset to quantify adult annual survival probability and remigration intervals for the Tortuguero, Costa Rica green turtle population. Annual survival probability was estimated at 0.85 (95% CI 0.75-0.92) using a recovery model and at 0.85 (95% CI 0.83-0.87) using an open robust design model. The two most common modes of remigration are 2 and 3 years. Annual survival probability is lower and remigration intervals are shorter than for other green turtle populations. Explanations for short remigration intervals include reproductive compensation due to historic population declines, availability of better quality food items, favorable environmental conditions, and short distance to the main foraging grounds. Variation in survival and remigration intervals have profound consequences for management and life history evolution. The short remigration intervals of Tortuguero green turtles partly offset mortality caused by turtle fishing in Nicaragua and mean that low juvenile survival represents a more urgent threat to the population than low adult survival. Low adult survival probability could result in selective pressure for earlier age at maturity

Synthesis of 2,6-Di(pyrazol-1-yl)pyrazine derivatives and the spin-state behavior of their iron(II) complexes

Chlorination of 2,6-bis(pyrazol-1-yl)pyrazine (bppz) with Na- ClO in acetic acid afforded 2,6-bis(4-chloropyrazol-1-yl)pyrazine (LCl). 2,6-Bis(4-bromopyrazol-1-yl)pyrazine (LBr), 2,6-bis(4-iodopyrazol-1- yl)pyrazine (LI), 2,6-bis(4-methylpyrazol- 1-yl)pyrazine (L Me), and 2,6-bis(4-nitropyrazol-1- yl)pyrazine (LNO ) were also prepared by reactions of the preformed 4-substituted pyrazoles with 2,6-dichloropyrazine. The reduction of LNO with iron powder gave 2,6-bis(4- aminopyrazol-1-yl)pyrazine (L NH) and LI was converted into 2,6-bis[4-(phenylethynyl)pyrazol-1-yl]pyrazine (LCCPh) by a Sonogashira coupling reaction. The salts [Fe(LMe)]X (X- = BF - and ClO -) underwent thermal spin-crossover abruptly at around 200 K in one and two steps, respectively. The [Fe(LMe)]X salts exhibited dif- ferent light-induced excited spin-state trapping (LIESST) behavior; the BF - salt behaves classically [T(LIESST) = 93 K], but the ClO - salt undergoes a multistep LIESST relaxation. In contrast, solid [Fe(L Cl)][BF]2 adopts a fixed 2:1 high/ low-spin-state population that does not change with temperature below 300 K, whereas [Fe(LBr)][BF]2 and [Fe(L I)][BF]2 form low-spin solvated crystals that are transformed into high-spin powders on drying. The pyrazinyl group in the LR ligands slightly stabilizes the low-spin state of the complexes, as determined by solution-phase magnetic measurements. The crystal structure of [Fe(LCCPh)(OH)z]- [BF]2 contains a disordered mixture of six- (z = 3) and sevencoordinate (z = 4) iron centers

Safety of Nonsteroidal Anti-inflammatory Drugs in Major Gastrointestinal Surgery: A Prospective, Multicenter Cohort Study

Background Significant safety concerns remain surrounding the use of nonsteroidal anti-inflammatory drugs (NSAIDs) following gastrointestinal surgery, leading to wide variation in their use. This study aimed to determine the safety profile of NSAIDs after major gastrointestinal surgery. Methods Consecutive patients undergoing elective or emergency abdominal surgery with a minimum one-night stay during a 3-month study period were eligible for inclusion. The administration of any NSAID within 3 days following surgery was the main independent variable. The primary outcome measure was the 30-day postoperative major complication rate, as defined by the Clavien–Dindo classification (Clavien–Dindo III–V). Propensity matching with multivariable logistic regression was used to produce odds ratios (OR) and 95 % confidence intervals. Results From 9264 patients, 23.9 % (n = 2212) received postoperative NSAIDs. The overall major complication rate was 11.5 % (n = 1067). Following propensity matching and adjustment, use of NSAIDs were not significantly associated with any increase in major complications (OR 0.90, 0.60–1.34, p = 0.560). Conclusions Early use of postoperative NSAIDs was not associated with an increase in major complications following gastrointestinal surgery