The ectomycorrhizal fungus Paxillus ammoniavirescens influences the effects of salinity on loblolly pine in response to potassium availability.

Salinity is an increasing problem in coastal areas affected by saltwater intrusion, with deleterious effects on tree health and forest growth. Ectomycorrhizal (ECM) fungi may improve the salinity tolerance of host trees, but the impact of external potassium (K+ ) availability on these effects is still unclear. Here, we performed several experiments with the ECM fungus Paxillus ammoniavirescens and loblolly pine (Pinus taeda L.) in axenic and symbiotic conditions at limited or sufficient K+ and increasing sodium (Na+ ) concentrations. Growth rate, biomass, nutrient content, and K+ transporter expression levels were recorded for the fungus, and the colonization rate, root development parameters, biomass, and shoot nutrient accumulation were determined for mycorrhizal and non-mycorrhizal plants. P. ammoniavirescens was tolerant to high salinity, although growth and nutrient concentrations varied with K+ availability and increasing Na+ exposure. While loblolly pine root growth and development decreased with increasing salinity, ECM colonization was unaffected by pine response to salinity. The mycorrhizal influence on loblolly pine salinity response was strongly dependent on external K+ availability. This study reveals that P. ammoniavirescens can reduce Na+ accumulation of salt-exposed loblolly pine, but this effect depends on external K+ availability.

Nucleation and growth of 2D covalent organic frameworks: polymerization and crystallization of COF monomers.

We establish a theoretical foundation for understanding the nucleation and growth of 2D covalent organic frameworks (COFs) from solution. This foundation should make it easier to realize some of the unique properties of COFs in targeted applications by allowing us to understand how processing variables such as solvent choice and linkage chemistry lead to larger crystalline domains. We use free energy techniques to map out the reaction mechanisms and activation energies of three fundamental reactions that are responsible for the early stages of 2D COF nucleation for a prototypical and commonly used 2D boronate ester material, COF-5, in water and methanol solvents. We show that the presence of water and methanol greatly catalyzes the boronate ester formation reactions, lowering the activation energy barrier by about 10 kcal mol-1 relative to an uncatalyzed reaction pathway. This is in good agreement with experimental observations by Smith and Dichtel (JACS 2014). Our crystallization studies also conclusively eliminate certain proposed mechanisms of growth, such as polymerization of large sheets followed by stacking, while strengthening the case for templated polymerization as a likely growth mechanism for COF crystals.

Growth of screen-detected abdominal aortic aneurysms in men: a bayesian analysis.

There is considerable interindividual variability in the growth of abdominal aortic aneurysms (AAAs), but an individual's growth observations, risk factors, and biomarkers could potentially be used to tailor surveillance. To assess the potential for tailoring surveillance, this study determined the accuracy of individualized predictions of AAA size at the next surveillance observation. A hierarchical Bayesian model was fitted to a total of 1,732 serial ultrasound measurements from 299 men in whom ultrasound screening identified an AAA. The data were best described by a nonlinear model with a constant first derivative of the AAA growth rate with size. The area under the receiver operating characteristic (ROC) curves for predicting whether an AAA was ≥40 or ≥50 mm at the next observation were 0.922 and 0.979, respectively, and the median root mean squared error was 2.52 mm. These values were nearly identical for models with or without plasma D-dimer effects.CPT: Pharmacometrics & Systems Pharmacology (2012) 1, e12; doi:10.1038/psp.2012.13; advance online publication 24 October 2012.

Hyperthermal organic thin film growth on surfaces terminated with self-assembled monolayers. I. The dynamics of trapping.

We have examined the initial stages of growth of a crystalline small molecule organic thin film, diindenoperylene (DIP), on SiO(2) surfaces terminated with a series of self-assembled monolayers (SAMs). In this study we make use of supersonic molecular beam techniques to vary the incident kinetic energy of the DIP molecules, and we use in situ, real time synchrotron x-ray scattering to monitor the buildup of each molecular layer in the growing thin film. We find that the effects of the SAMs are most apparent concerning growth in the sub-monolayer regime, before the substrate is entirely covered by the DIP thin film. In this coverage regime on bare SiO(2), and SiO(2) terminated with either hexamethyldisilazane or perflurooctyltrichlorosilane the adsorption dynamics are consistent with trapping-mediated adsorption as observed in more simple systems, where the probability of adsorption decreases significantly with increasing kinetic energy. Once these surfaces are covered with DIP, however, the adsorption probability increases, particularly at the highest incident kinetic energy, and the probability of adsorption exhibits only a weak dependence on the incident kinetic energy. In contrast, on surfaces terminated by octyl- (OTS) and octadecyltrichlorosilane (ODTS) the trapping probability is high and exhibits little dependence on the incident kinetic energy, essentially the same as what is observed on these same surfaces covered by DIP. We postulate, which is backed by the results of molecular dynamics simulations, that direct molecular insertion into the OTS and ODTS layers is a primary explanation for efficient trapping on these surfaces.

A genetic polymorphism in transforming growth factor beta receptor-2 is associated with serum osteopontin.

Osteopontin (OPN) is a secreted glycoprotein demonstrated to play an important role in inflammation. Transforming growth factor beta and a related signalling pathway have been implicated in control of OPN secretion. We examined the relationship between transforming growth factor beta receptor-1 and -2 (TGFBR1 and 2) single nucleotide polymorphisms (SNP) and serum OPN in 296 men from the Health in Men Study. Serum concentrations of OPN and 58 SNPs for TGFBR1 and 2 were assessed. One SNP in TGFBR2 was associated with serum OPN (TGFBR2 g.20690C>T, SNP ID rs4522809, P = 0.0007) after adjusting for multiple testing. This study suggests that polymorphism in TGFBR2 are associated with altered secretion of OPN, supporting a role for transforming growth factor beta in OPN production.

Possible association between genetic polymorphisms in transforming growth factor beta receptors, serum transforming growth factor beta1 concentration and abdominal aortic aneurysm.

BACKGROUND: Previous studies have suggested a role for transforming growth factor (TGF) beta and its receptor in thoracic aortic aneurysm, but their role in abdominal aortic aneurysm (AAA) is unknown. This study examined the possible association between TGF-beta receptor 1 and 2 (TGFBR-1 and -2) single nucleotide polymorphisms (SNPs) and serum TGF-beta1 with AAA. METHODS: Serum concentrations of TGF-beta1 and 58 SNPs for TGFBR-1 and -2 were examined in 1003 and 1711 men respectively from the Health In Men Study. Validation of SNPs was examined in a second referral cohort of 1043 subjects from New Zealand, of whom 654 had an AAA. RESULTS: Serum TGF-beta1 was not associated with AAA. Only one SNP in TGFBR-2 was weakly associated with AAA; TGFBR2 g.42917C > T, SNP ID rs1078985CC; odds ratio 0.64 (95 per cent confidence interval (c.i.) 0.45 to 0.93); P = 0.020 uncorrected; but this association did not hold after adjusting for multiple testing and was not validated in the New Zealand cohort: odds ratio 0.98 (95 per cent c.i. 0.50 to 1.94); P = 0.960. CONCLUSION: These findings suggest there is no important role of genetic polymorphisms in the main receptors for TGF-beta and circulating TGF-beta1 in AAA in older individuals. (c) 2009 British Journal of Surgery Society Ltd.

Determinants of endothelial function in a cohort of patients with peripheral artery disease.

OBJECTIVES: Endothelial dysfunction assessed by brachial artery flow-mediated dilatation (FMD) has been associated with cardiovascular events. There have been relatively few studies examining FMD or other measures of endothelial function in patients with peripheral artery disease (PAD). The aim of this study was to examine determinants of FMD in a homogenous cohort of patients with PAD. METHODS: We prospectively assessed patients presenting with life style-limiting intermittent claudication to establish the presence of cardiovascular risk factors, obesity and metabolic syndrome. Fasting serum was assayed for lipids, C-reactive protein, adiponectin, leptin, resistin and osteoprotegerin (OPG). FMD was measured by high-resolution ultrasound. RESULTS: Serum concentrations of OPG were elevated in patients with obesity and metabolic syndrome. FMD was impaired in patients with obesity and metabolic syndrome and negatively correlated with serum concentrations of OPG. By multiple regression analysis, metabolic syndrome was independently associated with impaired FMD after adjustment for age, smoking, ischaemic heart disease, cerebrovascular disease and severity of PAD. CONCLUSIONS: Our findings suggest that metabolic syndrome is an important determinant of endothelial function in patients with PAD, and OPG may be a useful biomarker of this effect.

The Escherichia coli signal transducers PII (GlnB) and GlnK form heterotrimers in vivo: fine tuning the nitrogen signal cascade.

The PII protein is Escherichia coli's cognate transducer of the nitrogen signal to the NRII (NtrB)/NRI (NtrC) two-component system and to adenylyltransferase. Through these two routes, PII regulates both amount and activity of glutamine synthetase. GlnK is the recently discovered paralogue of PII, with a similar trimeric x-ray structure. Here we show that PII and GlnK form heterotrimers, in E. coli grown in nitrogen-poor medium. In vitro, fully uridylylated heterotrimers of the two proteins stimulated the deadenylylation activity of adenylyltransferase, albeit to a lower extent than homotrimeric PII-UMP. Fully uridylylated GlnK did not stimulate, or hardly stimulated, the deadenylylation activity. We propose that uridylylated PII/GlnK heterotrimers fine-regulate the activation of glutamine synthetase. The PII/GlnK couple is a first example of prokaryotic signal transducer that can form heterotrimers. Advantages of hetero-oligomer formation as molecular mechanism for fine-regulation of signal transduction are discussed.

Aorto-right ventricular fistula: a late complication of aortic valve replacement.

We report the case of a patient who was found to have an aorto-right ventricular fistula 17 years after receiving a Björk-Shiley prosthetic aortic valve. A pseudoaneurysm had formed at the aortotomy suture line, and it had extended into the interventricular septum and had eventually opened into the right ventricle. Using transesophageal echocardiography, we identified the defect in the ascending aorta, and a left-to-right shunt. Aortography was used to confirm these findings. The pseudoaneurysm was successfully resected and the ascending aorta was replaced with a Dacron graft. To the best of our knowledge, no similar late complication of aortic valve replacement has been reported in the medical literature.

Search for life on Mars.

A multi-user integrated suite of instruments designed to optimize the search for evidence of life on Mars is described. The package includes: -Surface inspection and surface environment analysis to identify the potential Mars landing sites, to inspect the surface geology and mineralogy, to search for visible surficial microbial macrofossils, to study the surface radiation budget and surface oxidation processes, to search for niches for extant life. -Subsurface sample acquisition by core drilling -Analysis of surface and subsurface minerals and organics to characterize the surface mineralogy, to analyse the surface and subsurface oxidants, to analyse the mineralogy of subsurface aliquots, to analyse the organics present in the subsurface aliquots (elemental and molecular composition, isotopes, chirality). -Macroscopic and microscopic inspection of subsurface aliquots to search for life's indicators (paleontological, biological, mineralogical) and to characterize the mineralogy of the subsurface aliquots. The study is led by ESA Manned Spaceflight and Microgravity Directorate.

Molecular dynamics simulations of a winter flounder "antifreeze" polypeptide in aqueous solution.

A winter flounder antifreeze polypeptide (HPLC-6) has been studied in vacuo and in aqueous solution using molecular dynamics computer simulation techniques. The helical conformation of this polypeptide was found to be stable both in vacuum and in solution. The major stabilizing interactions were found to be the main-chain hydrogen bonds, a salt-bridge interaction, and solute-solvent hydrogen bonds. A significant bending in the middle of the polypeptide chain was observed both in vacuo and in solvent at 300 K. Possible causes of the bending are discussed. From simulations of mutant polypeptide molecules in vacuo, it is concluded that the bend in the native polypeptide was caused by side chain to backbone hydrogen bond competition involving the Thr 24 side chain and facilitated by strains on the helix resulting from the Lys 18-Glu 22 salt bridge.

Hemodynamic and metabolic effects of venoarterial cardiopulmonary support in coronary artery disease.

Coronary angioplasty was performed on 14 high-risk patients supported with venoarterial partial cardiopulmonary bypass. Hemodynamic, metabolic and physiologic parameters were monitored to assess the effect of cardiopulmonary support in conscious patients. Cardiopulmonary support caused a decrease in systolic (45 +/- 17 to 27 +/- 14 mm Hg, p less than 0.001), diastolic (23 +/- 12 to 14 +/- 8 mm Hg, p less than 0.005) and mean (29.7 +/- 13.2 to 18 +/- 9 mm Hg, p less than 0.001) pulmonary artery pressures. Aortic systolic (129 +/- 18 to 106 +/- 17 mm Hg, p less than 0.001), mean (89 +/- 19 to 84 +/- 19 mm Hg, p less than 0.05) and pulse (64 +/- 17 to 37 +/- 16 mm Hg, p less than 0.00001) pressures also decreased. Heart rate and aortic diastolic pressures were unchanged. End-systolic wall stress (122 +/- 48 x 10(3) to 96 +/- 44 x 10(3) dynes/cm2, p less than 0.001) and left ventricular end-diastolic diameter (5.7 +/- 0.8 to 5.5 +/- 0.9 cm, p less than 0.05) were reduced during partial cardiopulmonary bypass. After initiation of cardiopulmonary support, normal lactate extraction across the coronary circulation was diminished or converted to lactate production (38 +/- 23 to 2 +/- 29%, p less than 0.005). There was a marked reduction in hematocrit (41 +/- 4 to 28 +/- 5%, p less than 0.0001) and platelet count (259,000 +/- 57,600/ml to 145,900 +/- 46,000/ml, p less than 0.0001) after bypass. Cardiopulmonary bypass successfully supported all patients during balloon inflation, for an optimal angioplasty result.(ABSTRACT TRUNCATED AT 250 WORDS)

Monoclonal antibodies to Kunjin and Kokobera viruses.

Five monoclonal antibodies (MoAb) were produced to the envelope (E) protein of Kunjin (KUN) virus. Three of these were specific for the KUN/West Nile complex, and two reacted with epitopes that were common to the flavivirus family. These MoAb defined at least four distinct epitopes on the E protein of KUN virus. Eight MoAb were also produced to unidentified proteins of Kokobera (KOK) virus. Seven were specific for KOK, while the remaining antibody cross-reacted with Stratford virus and an unregistered flavivirus CS946. The application of these MoAb to arboviral surveillance is discussed.

Epitope analysis of the envelope and non-structural glycoproteins of Murray Valley encephalitis virus.

Previous studies have shown that antibodies produced against strategic flavivirus epitopes play an important role in recovery and immunity. Definition of the conformation and location of these epitopes and the degree of their conservation among flaviviruses is important to understanding the humoral response to flavivirus infection. In this study we have examined epitopes recognized by 14 monoclonal antibodies (MAbs) produced to the envelope (E) and non-structural (NS1) proteins of Murray Valley encephalitis virus (MVE). These antibodies were analysed for specificity, neutralization, haemagglutination inhibition (HI) and competitive binding. We have identified six distinct epitopes on the E protein which are located in four non-overlapping domains. MAbs to epitopes in one domain neutralized virus, were specific for MVE and Japanese encephalitis virus, and reacted with epitopes resistant to reduction. Two other E domains, one specific to MVE and the other shared by all flaviviruses, also contained neutralization sites and were stabilized by disulphide bonds. The fourth domain on E was conserved among the flaviviruses, sensitive to SDS denaturation and did not induce neutralizing antibody. Studies with MVE NS1 MAbs revealed that they were mostly type-specific, unreactive with conserved epitopes, and unreactive in HI and neutralization tests. The six epitopes identified on NS1 did not overlap and represent antigenic domains either resistant or sensitive to reduction. Immunoblotting of viral proteins in MVE-infected C6/36 cells revealed two distinct forms of NS1 and high Mr proteins of 97K and 108K that represented disulphide-linked heterodimers of E and NS1.

Form and function in the acquisition of Korean wh-questions.

In this paper the order in which wh-questions are acquired in the production and comprehension of two Korean children, aged 1;8-2;8 and 1;10-2;10, is analysed and compared with the available cross-linguistic data. Consistencies in acquisition order are hypothesized to be based on universals of cognitive development, which constrain the comprehension and production of wh-forms and influence the order in which mothers introduce them, and on functionally based similarities in the input of form/function pairs across children and languages. Discrepancies in acquisition order are attributed to differences in interactive style across caregivers and children, leading to different input frequencies of particular forms and individual children's selection of different forms for use.