Successional Change in Phosphorus Stoichiometry Explains the Inverse Relationship between Herbivory and Lupin Density on Mount St. Helens

The average nitrogen-to-phosphorus ratio (N?P) of insect herbivores is less than that of leaves, suggesting that P may mediate plant-insect interactions more often than appreciated. We investigated whether succession-related heterogeneity in N and P stoichiometry influences herbivore performance on N-fixing lupin (Lupinus lepidus) colonizing primary successional volcanic surfaces, where the abundances of several specialist lepidopteran herbivores are inversely related to lupin density and are known to alter lupin colonization dynamics. We examined larval performance in response to leaf nutritional characteristics using gelechiid and pyralid leaf-tiers, and a noctuid leaf-cutter.Apple JL, Wink M, Wills SE, Bishop JG (2009) Successional Change in Phosphorus Stoichiometry Explains the Inverse Relationship between Herbivory and Lupin Density on Mount St. Helens. PLoS ONE 4(11): e7807. doi:10.1371/journal.pone.000780

Calculation of the relative metastabilities of proteins in subcellular compartments of Saccharomyces cerevisiae

[abridged] Background: The distribution of chemical species in an open system at metastable equilibrium can be expressed as a function of environmental variables which can include temperature, oxidation-reduction potential and others. Calculations of metastable equilibrium for various model systems were used to characterize chemical transformations among proteins and groups of proteins found in different compartments of yeast cells. Results: With increasing oxygen fugacity, the relative metastability fields of model proteins for major subcellular compartments go as mitochondrion, endoplasmic reticulum, cytoplasm, nucleus. In a metastable equilibrium setting at relatively high oxygen fugacity, proteins making up actin are predominant, but those constituting the microtubule occur with a low chemical activity. A reaction sequence involving the microtubule and spindle pole proteins was predicted by combining the known intercompartmental interactions with a hypothetical program of oxygen fugacity changes in the local environment. In further calculations, the most-abundant proteins within compartments generally occur in relative abundances that only weakly correspond to a metastable equilibrium distribution. However, physiological populations of proteins that form complexes often show an overall positive or negative correlation with the relative abundances of proteins in metastable assemblages. Conclusions: This study explored the outlines of a thermodynamic description of chemical transformations among interacting proteins in yeast cells. The results suggest that these methods can be used to measure the degree of departure of a natural biochemical process or population from a local minimum in Gibbs energy.Comment: 32 pages, 7 figures; supporting information is available at http://www.chnosz.net/yeas

Effects of Tillage and Nitrogen Fertilizers on CH4 and CO2 Emissions and Soil Organic Carbon in Paddy Fields of Central China

Quantifying carbon (C) sequestration in paddy soils is necessary to help better understand the effect of agricultural practices on the C cycle. The objective of the present study was to assess the effects of tillage practices [conventional tillage (CT) and no-tillage (NT)] and the application of nitrogen (N) fertilizer (0 and 210 kg N ha−1) on fluxes of CH4 and CO2, and soil organic C (SOC) sequestration during the 2009 and 2010 rice growing seasons in central China. Application of N fertilizer significantly increased CH4 emissions by 13%–66% and SOC by 21%–94% irrespective of soil sampling depths, but had no effect on CO2 emissions in either year. Tillage significantly affected CH4 and CO2 emissions, where NT significantly decreased CH4 emissions by 10%–36% but increased CO2 emissions by 22%–40% in both years. The effects of tillage on the SOC varied with the depth of soil sampling. NT significantly increased the SOC by 7%–48% in the 0–5 cm layer compared with CT. However, there was no significant difference in the SOC between NT and CT across the entire 0–20 cm layer. Hence, our results suggest that the potential of SOC sequestration in NT paddy fields may be overestimated in central China if only surface soil samples are considered

Paediatric pancreaticobiliary endoscopy: a 21-year experience from a tertiary hepatobiliary centre and systematic literature review

BACKGROUND: In adults ERCP and endoscopic ultrasound (EUS) are standard methods of evaluating and treating many hepatopancreaticobiliary (HPB) conditions. HPB disease is being diagnosed with increasing frequency in children but information about role of ERCP and EUS and their outcomes in this population remain limited. Therefore the aims of this study were to describe the paediatric ERCP and EUS experience from a large tertiary referral HPB centre, and to systematically compare outcomes with those of other published series. METHODS: All patients <18 years undergoing an ERCP or EUS between January 1992-December 2014 were included. Indications for the procedure, rates of technical success, procedural adverse events and reinterventions were recorded in all cases. RESULTS: Ninety children underwent 111 procedures (87 ERCPs and 24 EUS). 53% (48) were female with a median age of 14 years (range: 3 months - 17 years). Procedures were performed under general anaesthesia (n = 48) or conscious sedation (n = 63). Common indications for ERCP included chronic or recurrent pancreatitis and biliary obstruction. Patients frequently had multiple comorbidities, with a median ASA grade of 2 (range 1-4). Therapeutic procedures performed included biliary or pancreatic sphincterotomy, common bile duct or pancreatic duct stone removal, biliary or pancreatic stent insertion, EUS-guided fine needle aspiration and endoscopic transmural drainage of pancreatic fluid collections. No adverse events were reported following ERCP but there was one complication requiring surgery following EUS guided cystenterostomy. CONCLUSION: ERCP and EUS in children and adolescents have high technical success rates and low rates of adverse events when performed in high volume HPB centres

Marked increase in veno-occlusive disease of the liver associated with methotrexate use for graft-versus-host disease prophylaxis in patients receiving busulfan/cyclophosphamide

The use of cyclosporine-A/methotrexate (CyA/MTX) for graft-versus-host disease (GVHD) prophylaxis is safe and effective for patients undergoing allogeneic bone marrow transplantation after preparation with cyclophosphamide and total body irradiation. We report 87 patients prepared for allogeneic transplant with busulfan 4 mg/kg/d orally for 4 days, followed by cyclophosphamide 60 mg/kg/d intravenously for 2 days (Bu4Cy2). A marked increase in hepatotoxicity was observed in 20 patients administered CyA/MTX, compared with 67 historical control patients who received CyA/methylprednisolone (CyA/MP) for GVHD prophylaxis with all other treatment and support variables remaining constant. The incidence of hyperbilirubinemia (bilirubin greater than or equal to 2 mg/dL) increased from 48% to 80% (P = .02), and the mean maximal bilirubin increased from 4.67 +/- 7.27 to 8.72 +/- 8.73 mg/dL (P = .04), when CyA/MTX was used in place of CyA/MP for GVHD prophylaxis. In addition, the incidence of veno-occlusive disease (VOD) increased from 18% to 70% (P = .0001), and death caused by VOD increased from 4.5% to 25% (P = .02). Survival was not significantly different for the two groups because of a higher non-VOD death rate in patients receiving CyA/MP for GVHD prophylaxis (P = .77). We suggest caution when using Bu4Cy2 in combination with CyA/MTX for GVHD prophylaxis.</jats:p

Marked increase in veno-occlusive disease of the liver associated with methotrexate use for graft-versus-host disease prophylaxis in patients receiving busulfan/cyclophosphamide

Abstract The use of cyclosporine-A/methotrexate (CyA/MTX) for graft-versus-host disease (GVHD) prophylaxis is safe and effective for patients undergoing allogeneic bone marrow transplantation after preparation with cyclophosphamide and total body irradiation. We report 87 patients prepared for allogeneic transplant with busulfan 4 mg/kg/d orally for 4 days, followed by cyclophosphamide 60 mg/kg/d intravenously for 2 days (Bu4Cy2). A marked increase in hepatotoxicity was observed in 20 patients administered CyA/MTX, compared with 67 historical control patients who received CyA/methylprednisolone (CyA/MP) for GVHD prophylaxis with all other treatment and support variables remaining constant. The incidence of hyperbilirubinemia (bilirubin greater than or equal to 2 mg/dL) increased from 48% to 80% (P = .02), and the mean maximal bilirubin increased from 4.67 +/- 7.27 to 8.72 +/- 8.73 mg/dL (P = .04), when CyA/MTX was used in place of CyA/MP for GVHD prophylaxis. In addition, the incidence of veno-occlusive disease (VOD) increased from 18% to 70% (P = .0001), and death caused by VOD increased from 4.5% to 25% (P = .02). Survival was not significantly different for the two groups because of a higher non-VOD death rate in patients receiving CyA/MP for GVHD prophylaxis (P = .77). We suggest caution when using Bu4Cy2 in combination with CyA/MTX for GVHD prophylaxis.</jats:p

Kinetics and binding capacity of six soils for structurally defined hydrolyzable and condensed tannins and related phenols

We investigated tannin–soil interactions by assessing the kinetics of sorption and sorption capacities, and their relationship to the chemical properties of six polyphenolic compounds and the textures of six soils. We developed a new extraction procedure for recovering tannins from soil samples by successive extraction with solvents of decreasing polarity.Sorption of polyphenolic compounds methyl gallate, catechin, oenothein B, pentagalloyl glucose, epigallocatechin gallate, and procyanidin dimer was determined using six soils with textures ranging from 7% silt–89% sand to 52% silt–22% sand. Sorption kinetics and capacity of the soils were determined using room temperature mixing with high performance liquid chromatography (HPLC) to determine polyphenol concentration. Tannins were extracted from soils loaded with known amounts of the model compounds using solvents with a range of polarities, and establishing recovery by HPLC. Multivariable regression was used to establish relationships between polyphenol properties and sorption, and between soil texture and sorption.Sorption of the polyphenols followed the Langmuir isotherm with unique binding capacity and kinetics of sorption for each compound. Tannin sorption was correlated to molecular weight and polarity. For an Ultisol pasture soil, up to 18.7 mg g−1 soil of the large, hydrophobic compound epigallocatechin gallate was bound compared to only 5.11 mg g−1 soil of the smaller, more polar compound methyl gallate. Kinetics of sorption also varied with sorption reaching equilibrium between 75 and 350 min. Silt and sand composition affected polyphenol sorption in a unique fashion for each polyphenol. Using sequential extraction with solvents ranging from polar (water) to non-polar (hexane), we extracted up to 42% of the material that had been loaded on the soil as a mixture of five polyphenols.This work demonstrates that the likely fate of tannins and related polyphenols from plant sources is rapid sorption, with little likelihood of release of unmodified tannins from the soil by leaching. Tight sorption impedes recovery and analysis of soil tannins, but better methods for extraction may improve our knowledge of tannins in the soil