Long-term relationships between environment and abundance in wheat of Phaeosphaeria nodorum and Mycosphaerella graminicola

Relationships between weather, agronomic factors and wheat disease abundance were examined to determine possible causes of variability on century time scales. In archived samples of wheat grain and leaves obtained from the Rothamsted Broadbalk experiment archive (1844-2003), amounts of wheat, Phaeosphaeria nodorum and Mycosphaerella graminicola DNA were determined by quantitative polymerase chain reaction (PCR). Relationships between amounts of pathogens and environmental and agronomic factors were examined by multiple regression. Wheat DNA decayed at approx. 1% yr(-1) in stored grain. No M. graminicola DNA was detected in grain samples. Fluctuations in amounts of P. nodorum in grain were related to changes in spring rainfall, summer temperature and national SO2 emission. Differences in amounts of P. nodorum between grain and leaf were related to summer temperature and spring rainfall. In leaves, annual variation in spring rainfall affected both pathogens similarly, but SO2 had opposite effects. Previous summer temperature had a highly significant effect on M. graminicola. Cultivar effects were significant only at P = 0.1. Long-term variation in P. nodorum and M. graminicola DNA in leaf and grain over the period 1844-2003 was dominated by factors related to national SO2 emissions. Annual variability was dominated by weather factors occurring over a period longer than the growing season.

Exudate flavones and flavanones in Origanum species and their interspecific variation

Surface flavonoids in nine species of Origanum, representing taxa from all three of the currently recognised subgeneric groups, were examined both by HPLC coupled to diode-array detection and APCI-MS. Many of the flavonoids present were characterised by O-substituent at C-6 (OH, OMe) and/or C-8 (OMe). In total, 25 flavones and flavanones are described in this study, of which 13 are new to the genus and 5,4'-dihydroxy-6,7,3'-trimethoxyflavanone is reported for the first time. Taxa in subgeneric Group A accumulated flavonoids with methoxyl groups at both C-6 and C-4'; however, taxa in subgeneric Group B did not accumulate 4'-methoxylated compounds, and taxa in Group C did not accumulate 6-methoxylated compounds. (C) 2008 Elsevier Ltd. All rights reserved.

Expression of FoxC, FoxF, FoxL1, and FoxQ1 genes in the dogfish scyliorhinus canicula defines ancient and derived roles for fox genes in vertebrate development

In the human genome, members of the FoxC, FoxF, FoxL1, and FoxQ1 gene families are found in two paralagous clusters. Here we characterize all four gene families in the dogfish Seyliorhinus canicula, a member of the cartilaginous fish lineage that diverged before the radiation of osteichthyan vertebrates. We identify two FoxC genes, two FoxF genes, and single FoxQ1 and FoxL1 genes, demonstrating cluster duplication preceded the radiation of gnathostomes. The expression of all six genes was analyzed by in situ hybridization. The results show conserved expression of FoxL1, FoxF, and FoxC genes in different compartments of the mesoderm and of FoxQ1 in pharyngeal endoderm and its derivatives, confirming these as ancient sites of Fox gene expression, and also illustrate multiple cases of lineage-specific expression domains. Comparison to invertebrate chordates shows that the majority of conserved vertebrate expression domains mark tissues that are part of the primitive chordate body plan.

Radon in homes and risk of lung cancer: collaborative analysis of individual data from 13 European case-control studies

Objective: To determine the risk of lung cancer associated with exposure at home to the radioactive disintegration products of naturally Occurring radon gas. Design: Collaborative analysis of individual data from 13 case-control studies of residential radon and lung cancer. Setting Nine European countries. Subjects 7148 cases Of lung cancer and 14 208 controls. Main outcome measures: Relative risks of lung cancer and radon gas concentrations in homes inhabited during the previous 5-34 years measured in becquerels (radon disintegrations per second) per cubic incite (Bq/m(3)) Of household air. Results: The mean measured radon concentration in homes of people in tire control group was 97 Bq/m(3), with 11% measuring > 200 and 4% measuring > 400 Bq/m(3). For cases of lung cancer the mean concentration was 104 Bq/m(3). The risk of lung cancer increased by 8.4% (95% confidence interval 3.0% to 15.8%) per 100 Bq/m(3) increase in measured radon (P = 0.0007). This corresponds to an increase of 16% (5% to 31%) per 100 Bq/m(3) increase in usual radon-that is, after correction for the dilution caused by random uncertainties in measuring radon concentrations. The dose-response relation seemed to be linear with no threshold and remained significant (P=0.04) in analyses limited to individuals from homes with measured radon < 200 Bq/m(3). The proportionate excess risk did not differ significantly with study, age, sex, or smoking. In the absence of other causes of death, the absolute risks of lung cancer by age 75 years at usual radon concentrations of 0, 100, and 400 Bq/m(3) would be about 0.4%, 0.5%, and 0.7%, respectively, for lifelong non-smokers, and about 25 times greater (10%, 12%, and 16%) for cigarette smokers. Conclusions: Collectively, though not separately, these studies show appreciable hazards from residential radon, particularly for smokers and recent ex-smokers, and indicate that it is responsible for about 2% of all deaths from cancer in Europe.

Inhibition of coxsackie B virus infection by soluble forms of its receptors: Binding affinities, altered particle formation, and competition with cellular receptors

We previously reported that soluble decay-accelerating factor (DAF) and coxsackievirus-adenovirus receptor (CAR) blocked coxsackievirus 133 (CVB3) myocarditis in mice, but only soluble CAR blocked CVB3-mediated pancreatitis. Here, we report that the in vitro mechanisms of viral inhibition by these soluble receptors also differ. Soluble DAF inhibited virus infection through the formation of reversible complexes with CVB3, while binding of soluble CAR to CVB induced the formation of altered (A) particles with a resultant irreversible loss of infectivity. A-particle formation was characterized by loss of VP4 from the virions and required incubation of CVB3-CAR complexes at 37 degrees C. Dimeric soluble DAF (DAF-Fc) was found to be 125-fold-more effective at inhibiting CVB3 than monomeric DAF, which corresponded to a 100-fold increase in binding affinity as determined by surface plasmon resonance analysis. Soluble CAR and soluble dimeric CAR (CAR-Fc) bound to CVB3 with 5,000- and 10,000-fold-higher affinities than the equivalent forms of DAF. While DAF-Fc was 125-fold-more effective at inhibiting virus than monomeric DAF, complement regulation by DAF-Fc was decreased 4 fold. Therefore, while the virus binding was a cooperative event, complement regulation was hindered by the molecular orientation of DAF-Fc, indicating that the regions responsible for complement regulation and virus binding do not completely overlap. Relative contributions of CVB binding affinity, receptor binding footprint on the virus capsid, and induction of capsid conformation alterations for the ability of cellular DAF and CAR to act as receptors are discussed.

Some transition metal complexes derived from mono- and di-ethynyl perfluorobenzenes

Transition metal alkynyl complexes containing perfluoroaryl groups have been prepared directly from trimethylsilyl-protected mono- and di-ethynyl perfluoroarenes by simple desilylation/metallation reaction sequences. Reactions between Me3SiC CC6F5 and RuCl(dppe)Cp'[Cp' = Cp, Cp*] in the presence of KF in MeOH give the monoruthenium complexes Ru(C CC6F5)(dppe)Cp'[Cp' = Cp (2); Cp* (3)], which are related to the known compound Ru(C CC6F5)(PPh3)(2)Cp (1). Treatment of Me3SiC CC6F5 with Pt-2(mu-dppm)(2)Cl-2 in the presence of NaOMe in MeOH gave the bis(alkynyl) complex Pt-2(mu-dppm)(2)(C CC6F5)(2) (4). The Pd(0)/Cu(I)-catalysed reactions between Au(C CC6F5)(PPh3) and Mo( CBr)(CO)(2) Tp* [Tp* = hydridotris(3.5-dimethylpyrazoyl)borate], Co-3(mu(3)-CBr)(mu-dppm)(CO)(7) or IC CFc [Fc = (eta(5)-C5H4)FeCp] afford Mo( CC CC6F5)(CO)(2)Tp* (5), Co-3(mu 3-CC CC6F5)(mu-dppm)(CO)(7) (6) and FcC CC CC6F5 (7), respectively. The diruthenium complexes 1,4-{Cp'(PP)RuC C}(2)C6F4 [(PP)Cp'=(PPh3)(2)Cp (8); (dppe)Cp (9); (dppe)Cp* (10)] are prepared from 1,4-(Me3SiC C)(2)C6F4 in a manner similar to that described for the monoruthenium complexes 1-3. The non-fluorinated complexes 1,4-{Cp'(PP)RuC C}(2)C6H4 [(PP)Cp' = (PPh3)(2)Cp (11); ( dppe) Cp (12); ( dppe) Cp* (13)], prepared for comparison, are obtained from 1,4-(Me3SiC C)(2)C6H4. Spectro-electrochemical studies of the ruthenium aryl and arylene alkynyl complexes 2-3 and 8-13, together with DFT-based computational studies on suitable model systems, indicate that perfluorination of the aromatic ring has little effect on the electronic structures of these compounds, and that the frontier orbitals have appreciable diethynylphenylene character. Molecular structure determinations are reported for the fluoroaromatic complexes 1, 2, 3, 6 and 10.

Nematic and columnar ordering of a PEG-peptide conjugate in aqueous solution

The self-assembly in aqueous solution of a PEG-peptide conjugate is studied by spectroscopy, electron microscopy, rheology and small-angle Xray and neutron scattering (SAXS and SANS). The peptide fragment, FFKLVFF is based on fragment KLVFF of the amyloid beta-peptide, A beta(16-20), extended by two hydrophobic phenylalanine units. This is conjugated to PEG which confers water solubility and leads to distinct self-assembled structures. Small-angle scattering reveals the formation of cylindrical fibrils comprising a peptide core and PEG corona. This constrained structure leads to a model parallel beta-sheet self-assembled structure with a radial arrangement of beta sheets. Oil increasing concentration, successively nematic and hexagonal columnar phases are formed. The flow-induced alignment of both structures was studied in situ by SANS using a Couette cell. Shear-induced alignment is responsible for the shear thinning behaviour observed by dynamic shear rheometry. Incomplete recovery of moduli after cessation of shear is consistent with the observation from SANS of retained orientation in the sample.

Quantum mechanics studies of the tautomers of dlhydrodiacetylformoin, an important Maillard intermediate and the synthesis of furaneol

Conformational analyses have been carried out on the acyclic and cyclic forms of dihydrodiacetylformoin, an important Maillard intermediate and precursor for furaneol. For the acyclic forms, the 2,5-dicarbonyl isomers have the lowest energy, while for the cyclic forms, the 3-carbonyl are favoured over the 4-carbonyl isomers. The likely path for cyclisation is investigated and it is shown that the favoured path is dependent upon the relative chiralities of the carbon atoms and in particular that the reaction proceeds more readily if C2 and C3 have different chiralities. After cyclisation, the reaction path to produce furaneol proceeds via the loss of a water molecule. This reaction has been studied with a model including two water molecules and a hydroxide anion and shows relatively low-energy barriers. (C) 2008 Published by Elsevier B.V.

Low-molecular-weight gelators: Elucidating the principles of gelation based on gelator solubility and a cooperative self-assembly model

This paper highlights the key role played by solubility in influencing gelation and demonstrates that many facets of the gelation process depend on this vital parameter. In particular, we relate thermal stability (T-gel) and minimum gelation concentration (MGC) values of small-molecule gelation in terms of the solubility and cooperative self-assembly of gelator building blocks. By employing a van't Hoff analysis of solubility data, determined from simple NMR measurements, we are able to generate T-calc values that reflect the calculated temperature for complete solubilization of the networked gelator. The concentration dependence of T-calc allows the previously difficult to rationalize "plateau-region" thermal stability values to be elucidated in terms of gelator molecular design. This is demonstrated for a family of four gelators with lysine units attached to each end of an aliphatic diamine, with different peripheral groups (Z or Bee) in different locations on the periphery of the molecule. By tuning the peripheral protecting groups of the gelators, the solubility of the system is modified, which in turn controls the saturation point of the system and hence controls the concentration at which network formation takes place. We report that the critical concentration (C-crit) of gelator incorporated into the solid-phase sample-spanning network within the gel is invariant of gelator structural design. However, because some systems have higher solubilities, they are less effective gelators and require the application of higher total concentrations to achieve gelation, hence shedding light on the role of the MGC parameter in gelation. Furthermore, gelator structural design also modulates the level of cooperative self-assembly through solubility effects, as determined by applying a cooperative binding model to NMR data. Finally, the effect of gelator chemical design on the spatial organization of the networked gelator was probed by small-angle neutron and X-ray scattering (SANS/SAXS) on the native gel, and a tentative self-assembly model was proposed.

Proteomic profiling of neuromas reveals alterations in protein composition and local protein synthesis in hyper-excitable nerves

Neuropathic pain may arise following peripheral nerve injury though the molecular mechanisms associated with this are unclear. We used proteomic profiling to examine changes in protein expression associated with the formation of hyper-excitable neuromas derived from rodent saphenous nerves. A two-dimensional difference gel electrophoresis ( 2D-DIGE) profiling strategy was employed to examine protein expression changes between developing neuromas and normal nerves in whole tissue lysates. We found around 200 proteins which displayed a > 1.75-fold change in expression between neuroma and normal nerve and identified 55 of these proteins using mass spectrometry. We also used immunoblotting to examine the expression of low-abundance ion channels Nav1.3, Nav1.8 and calcium channel alpha 2 delta-1 subunit in this model, since they have previously been implicated in neuronal hyperexcitability associated with neuropathic pain. Finally, S(35)methionine in vitro labelling of neuroma and control samples was used to demonstrate local protein synthesis of neuron-specific genes. A number of cytoskeletal proteins, enzymes and proteins associated with oxidative stress were up-regulated in neuromas, whilst overall levels of voltage-gated ion channel proteins were unaffected. We conclude that altered mRNA levels reported in the somata of damaged DRG neurons do not necessarily reflect levels of altered proteins in hyper-excitable damaged nerve endings. An altered repertoire of protein expression, local protein synthesis and topological re-arrangements of ion channels may all play important roles in neuroma hyper-excitability.

A study of co-precipitated bimetallic gold catalysts for water-gas shift reaction

Synthesis, testing and characterisation of bimetallic gold, Au-M on ceria as catalysts were carried out for low temperature water-gas shift reaction (WGS). Amongst the entire screened catalysts 3 wt% (AU-Pt)/CeO2 displayed the best WGS activity than the monometallic promotors, giving the light-off curve at the lowest temperature in the range 100-300 degrees C. (Au-Pd)/CeO2 also achieved the same activity but at a higher temperature. It was also found that WGS activity was strongly correlated with the surface reducibility which in turn depended on the modified local electronic band structure of promoted ceria. These results clearly suggest that the key role of bimetallic promoter may involve in facilitating the creation of defective reduced surface by exerting its local electronic effect on ceria to form the surface germinal -OH groups in water which act as active sites for enhanced WGS activity. (C) 2008 Elsevier B.V. All rights reserved.

The syntheses, structures and redox properties of phosphine-gold(I) and triruthenium-carbonyl cluster derivatives of tolans

The syntheses of several ethynyl-gold(I) phosphine substituted tolans (1,2-diaryl acetylenes) of general form [Au(C=CC6H4C=CC6H4X)(PPh3)] are described [X = Me (2a), OMe (2b), CO2Me (2c), NO2 (2d), CN (2e)]. These complexes react readily with [Ru-3(CO) 10(mu-dppm)] to give the heterometallic clusters [Ru3(mu-AuPPh3)(mu-eta(1), eta(2)-C2C6H4C, CC6H4X)(CO)(7)(mu-dppm)] (3a-e). The crystallographically determined molecular structures of 2b, 2d, 2e and 3a-e are reported here, that of 2a having been described on a previous occasion. Structural, spectroscopic and electrochemical studies were conducted and have revealed little electronic interaction between the remote substituent and the organometallic end-caps. (C) 2007 Elsevier B. V. All rights reserved.

Introduction of vinyl and hydroxymethyl functionalities at C-4 of glucose-derived substrates: synthesis of spirocyclic, bicyclic, and tricyclic nucleosides

Installing hydroxymethyl and hydroxyethyl substitutions at C-4 through vinylation and hydroboration-oxidation reactions of the C-4 bis-hydroxymethyl derivative of D-glucose based substrate, and inserting heteroatoms thereafter permitted formation of N-, O-, or S-heterocycles leading to [4,5]or [5,5]-spirocycles and a bicyclo[3.3.0]octane product. Some of the spirocycles were converted to spironucleosides under Vorbruggen glycosidation reaction conditions. Similarly, the bicyclic product was elaborated to the corresponding bicyclic nucleoside as well as an unexpected tricyclic nucleoside.

2D parallel interpenetration of [M-2(bpp)(4)X-4] [M, Fe(II)/Co(II); bpp, 4,4 '-trimethylenedipyridine; X, SCN-SeCN- and N-3(-)] complexes: pseudohalide-dependent conformation of bpp

Three coordination complexes of Co(II)/Fe(II) with 4,4'-trimethylenedipyridine (bpp) and pseudohalides (SCN-, SeCN- and N-3(-)) have been synthesized. The complexes have been characterized by X-ray single crystal structure determination. They are isomorphous having 2D layers in which two independent wavy nets display parallel interwoven structures. Pseudohalide binds metal centers through N terminal and occupies the trans axial positions of the octahedral metal coordination environment. Pseudohalide remains pendant on both sides of the polymeric layer and help the stacking through hydrogen bonding. The conformation of bpp in the interpenetrated nets is observed to be dependent on the choice of pseudohalide. (C) 2008 Elsevier Inc. All rights reserved.