Battling the biotypes of balsam: the biological control of Impatiens glandulifera using the rust fungus Puccinia komarovii var. glanduliferae in GB.

Impatiens glandulifera, or Himalayan balsam, is a prolific invader of riverine habitats. Introduced from the Himalayas for ornamental purposes in 1839, this annual species has naturalised across Great Britain (GB) forming dense monocultures with negative affects across whole ecosystems. In 2006 a programme exploring biocontrol as an alternative control method was initiated and to date, two strains of the rust fungus Puccinia komarovii var. glanduliferae have been released. To better understand the observed differences in susceptibility of GB Himalayan balsam stands to the two rust strains, inoculation studies were conducted using urediniospores and basidiospores. Experiments revealed large variation in the susceptibility of stands to urediniospores of the two rust strains, with some resistant to both. Furthermore, the infectivity of basidiospores was found to differ, with some stands fully susceptible to the urediniospore stage, being immune to basidiospore infection. Therefore, before further rust releases at new sites, it is necessary to ensure complete compatibility of the invasive stands with both urediniospores and basidiospores. However, for successful control across GB it is essential that plant biotypes are matched to the most virulent rust strains. This will involve additional strains from the native range to tackle those biotypes resistant to the strains currently released.

Comparison of the metabolism of 10 chemicals in human and pig skin explants.

Skin metabolism is important to consider when assessing local toxicity and/or penetration of chemicals and their metabolites. If human skin supply is limited, pig skin can be used as an alternative. To identify any species differences, we have investigated the metabolism of 10 chemicals in a pig and human skin explant model. Phase I metabolic pathways in skin from both species included those known to occur via cytochrome P450s, esterases, alcohol dehydrogenases and aldehyde dehydrogenases. Common Phase II pathways were glucuronidation and sulfation but other conjugation pathways were also identified. Chemicals not metabolized by pig skin (caffeine, IQ and 4-chloroaniline) were also not metabolized by human skin. Six chemicals metabolized by pig skin were metabolized to a similar extent (percentage parent remaining) by human skin. Human skin metabolites were also detected in pig skin incubations, except for one unidentified minor vanillin metabolite. Three cinnamyl alcohol metabolites were unique to pig skin but represented minor metabolites. There were notable species differences in the relative amounts of common metabolites. The difference in the abundance of the sulfate conjugates of resorcinol and 4-amino-3-nitrophenol was in accordance with the known lack of aryl sulfotransferase activity in pigs. In conclusion, while qualitative comparisons of metabolic profiles were consistent between pig and human skin, there were some quantitative differences in the percentage of metabolites formed. This preliminary assessment suggests that pig skin is metabolically competent and could be a useful tool for evaluating potential first-pass metabolism before testing in human-derived tissues.

Analytic expressions for electron-ion temperature equilibration rates from the Lenard-Balescu equation.

In this work, we elucidate the mathematical structure of the integral that arises when computing the electron-ion temperature equilibration time for a homogeneous weakly coupled plasma from the Lenard-Balescu equation. With some minor approximations, we derive an analytic formula, requiring no input Coulomb logarithm, for the equilibration rate that is valid for moderate electron-ion temperature ratios and arbitrary electron degeneracy. For large temperature ratios, we derive the necessary correction to account for the coupled-mode effect, which can be evaluated very efficiently using ordinary Gaussian quadrature.

Systemic Treatment with a miR-146a Mimic Suppresses Endotoxin Sensitivity and Partially Protects Mice from the Progression of Acute Graft-versus-Host Disease.

Acute GVHD (aGVHD) is driven by interactions between the allogenic T cell response, inflammation, tissue injury and microbial products that enter the circulation when protective barriers such as the intestinal epithelium become compromised. Mice with aGVHD become hypersensitive to LPS, secreting large quantities of inflammatory mediators that exacerbate tissue injury. We hypothesized that microRNA (miR) modulators could be used in vivo to mitigate LPS hypersensitivity, altering the course of aGVHD. Using the C57BL/6 → (C57BL/6 × DBA/2)F1 -hybrid model of aGVHD, we measured intestinal permeability over time and used a qPCR array to detect concomitant changes in the expression levels of certain microRNAs (miRs) in the intestine. Large increases in permeability were seen on day 15, when endotoxemia becomes detectable and GVHD-associated histopathological lesions develop. Amongst the miRs with altered expression levels were some that regulate sensitivity to endotoxin. We chose to focus on miR-146a and treated recipient mice systemically with a miR-146a mimic early in the GVH reaction. This led to a reduction in the burst of IFNγ that likely plays a priming role in the mechanism underlying heightened sensitivity to endotoxin. LPS-induced TNFα release and GVHD-associated weight loss were also diminished and survival was prolonged. In summary, systemic treatment with a miR-146a mimic dampens the heightened sensitivity to LPS that occurs concomitantly with increased intestinal permeability and provides partial protection from the progression of acute GVHD.

Bupropion Hydrochloride.

Bupropion hydrochloride is a norepinephrine-dopamine disinhibitor (NDDI) approved for the treatment of depression and smoking cessation. Bupropion is a trimethylated monocyclic phenylaminoketone second-generation antidepressant, which differs structurally from most antidepressants, and resides in a novel mechanistic class that has no direct action on the serotonin system. Comprehensive chemical, physical, and spectroscopic profiles are presented. This analytical profile provides an extensive spectroscopic investigation utilizing mass spectrometry, one- and two-dimensional NMR, solid-state NMR, IR, NIR, Raman, UV, and X-ray diffraction. The profile also includes significant wet chemistry studies for pH, solubility, solution, and plasma stability. Both HPLC and UPLC methodology are presented for bupropion and its related impurities or major metabolites. The profile concludes with an overview of biological properties that includes toxicity, drug metabolism, and pharmacokinetics.

First Report of Colletotrichum truncatum Causing Stem Cankers on Jatropha curcas in Burkina Faso.

A new disease was identified on the biofuel crop Jatropha curcas in 2012 in Burkina Faso that is causing serious yield losses. The disease was found to be widespread in both Sissili and Comoé Provinces. It causes characteristic leaf lesions, fruit necrosis, and cankers on young stems and branches. There was evidence of multiple infections on plants over the growing season, with regrowth evident from below old cankers, but there was little fruit production from infected branches. A detailed monitoring and assessment was undertaken of the disease progress in a severely infected field, over a 7-week period. The disease symptoms progressed from chlorosis through a necrotic phase and, in approximately 83% of replicates, stem cankers developed that resulted in dieback and lodging of branches. Colletotrichum truncatum and a member of the species complex C. gloeosporioides sensu lato were consistently isolated from fresh stem samples showing early symptoms (chlorosis). Koch's postulates were undertaken, to establish the pathogenicity of the two species. No symptoms were observed on plants inoculated with C. gloeosporioides; however, leaf and stem lesions developed after inoculation with C. truncatum, which was reisolated from the diseased tissue, confirming it as the disease-causing agent. Preliminary management practices for the disease are proposed.

Lack of functional TSLP receptors mitigates Th2 polarization and the establishment and growth of 4T1 primary breast tumours but has different effects on tumour quantities in the lung and brain.

The 4T1 mammary carcinoma cell line produces TSLP. We had hypothesized that TSLP promotes the development of a permissive environment for the growth and metastasis of primary tumour and that this is associated with a Th2-polarized antitumour immune response. We found that, in Tslpr(-/-) mice, the mean tumour diameters were smaller from days 27 to 40, and relatively fewer tumour cells were present in the lung, compared with wild-type mice. Polarization of the Th2 cytokine profile was also diminished in Tslpr(-/-) mice. These findings confirmed those reported previously by others. Here, we further show that primary tumours are established less often in Tslpr(-/-) mice and that, unexpectedly, the relative number of tumour cells in the brain is greater in Tslpr(-/-) mice compared with wild-type mice. Findings from our cytotoxicity assays show that 4T1-directed lysis is undetectable in both WT and Tslpr(-/-) mice, ruling out the possibility that altered cytotoxic responses in Tslpr(-/-) mice are responsible for the differences we observed. In a human tissue microarray, positive staining for TSLP was seen in tumour cells from breast cancer tissue, but it was also seen in normal glandular epithelial cells from normal breast tissue, which has not been shown before. Thus, our findings provide new insight into the effects of TSLP in metastatic breast cancer.

Product quality of parenteral vancomycin products in the United States.

In response to concerns raised about the quality of parenteral vancomycin products, the U.S. Food and Drug Administration (FDA) is investigating the product quality of all FDA-approved parenteral vancomycin products available in the United States. Product quality was evaluated independently at two FDA Office of Testing and Research (FDA-OTR) sites. In the next phase of the investigation, being done in collaboration with the National Institute of Allergy and Infectious Diseases, the in vivo activity of these products will be evaluated in an appropriate animal model. This paper summarizes results of the FDA investigation completed thus far. One site used a validated ultrahigh-pressure liquid chromatography method (OTR-UPLC), and the second site used the high-performance liquid chromatography (HPLC) method for related substances provided in the British Pharmacopeia (BP) monograph for vancomycin intravenous infusion. Similar results were obtained by the two FDA-OTR laboratories using two different analytical methods. The products tested had 90 to 95% vancomycin B (active component of vancomycin) by the BP-HPLC method and 89 to 94% vancomycin by OTR-UPLC methods. Total impurities were 5 to 10% by BP-HPLC and 6 to 11% by OTR-UPLC methods. No single impurity was >2.0%, and the CDP-1 level was ≤ 2.0% across all products. Some variability in impurity profiles of the various products was observed. No adverse product quality issues were identified with the six U.S. vancomycin parenteral products. The quality parameters of all parenteral vancomycin products tested surpassed the United States Pharmacopeia acceptance criteria. Additional testing will characterize in vivo performance characteristics of these products.

Immunomodulatory effects of palifermin (recombinant human keratinocyte growth factor) in an SLE-like model of chronic graft-versus-host disease.

Keratinocyte growth factor (KGF) promotes epithelial cell proliferation and survival. Recombinant human KGF, also known as palifermin, protects epithelial cells from injury induced by chemicals, irradiation and acute murine graft-versus-host disease (GVHD). Findings from our studies and others have shown that palifermin also has immunomodulatory properties. In a model of acute GVHD, we showed that it shifts the immune response from one in which Th1 cytokines dominate to mixed Th1 and Th2 cytokine profile. Using the DBA/2→(C57BL/6 × DBA/2)F(1)-hybrid model of chronic, systemic lupus erythematosus-like GVHD, we showed that palifermin treatment is associated with higher levels of Th2 cytokines, the production of anti-nuclear antibodies, cryoglobulinemia and the development of more severe pathological changes in the kidney. The aim of our current study was to gain a better understanding of the immunobiology of KGF by further characterizing the palifermin-mediated effects in this model of chronic GVHD. Because the pathological changes we observed resemble those seen in thymic stromal lymphopoietin (TSLP) transgenic mice, we had originally hypothesized that palifermin might augment TSLP levels. Surprisingly, we did not observe an increase in thymic TSLP mRNA expression in palifermin-treated recipients. We did, however, observe some differences in the percentages of CD4(+) CD25(+) Foxp3(+) regulatory T cells in the spleen at some time points in palifermin-treated recipients. Most importantly, we found that TGFß levels were higher in palifermin-treated recipients early in the GVH reaction, raising the possibility that KGF might indirectly induce the development of fibrosis and glomerulonephritis through a pathway involving TGFß.

A review of the electrophilic reaction chemistry involved in covalent protein binding relevant to toxicity.

Several pieces of legislation have led to an increased interest in the use of in silico methods, specifically the formation of chemical categories for the assessment of toxicological endpoints. For a number of endpoints, this requires a detailed knowledge of the electrophilic reaction chemistry that governs the ability of an exogenous chemical to form a covalent adduct. Historically, this chemistry has been defined as compilations of structural alerts without documenting the associated electrophilic chemistry mechanisms. To address this, this article has reviewed the literature defining the structural alerts associated with covalent protein binding and detailed the associated electrophilic reaction chemistry. This information is useful to both toxicologists and regulators when using the chemical category approach to fill data gaps for endpoints involving covalent protein binding. The structural alerts and associated electrophilic reaction chemistry outlined in this review have been incorporated into the OECD (Q)SAR Toolbox, a freely available software tool designed to fill data gaps in a regulatory environment without the need for further animal testing.

Assessment of methods to define the applicability domain of structural alert models.

It is important that in silico models for use in chemical safety legislation, such as REACH, are compliant with the OECD Principles for the Validation of (Q)SARs. Structural alert models can be useful under these circumstances but lack an adequately defined applicability domain. This paper examines several methods of domain definition for structural alert models with the aim of assessing which were the most useful. Specifically, these methods were the use of fragments, chemical descriptor ranges, structural similarity, and specific applicability domain definition software. Structural alerts for mutagenicity in Derek for Windows (DfW) were used as examples, and Ames test data were used to define and test the domain of chemical space where the alerts produce reliable results. The usefulness of each domain was assessed on the criterion that confidence in the correctness of predictions should be greater inside the domain than outside it. By using a combination of structural similarity and chemical fragments a domain was produced where the majority of correct positive predictions for mutagenicity were within the domain and a large proportion of the incorrect positive predictions outside it. However this was not found for the negative predictions; there was little difference between the percentage of true and false predictions for inactivity which were found as either within or outside the applicability domain. A hypothesis for the occurrence of this difference between positive and negative predictions is that differences in structure between training and test compounds are more likely to remove the toxic potential of a compound containing a structural alert than to add an unknown mechanism of action (structural alert) to a molecule which does not already contain an alert. This could be especially true for well studied end points such as the Ames assay where the majority of mechanisms of action are likely to be known.

The genetics of speciation: genes of small effect underlie sexual isolation in the Hawaiian cricket Laupala.

Sexual behaviours often evolve rapidly and are critical for sexual isolation. We suggest that coordinated sexual signals and preferences generate stabilizing selection, favouring the accumulation of many small-effect mutations in sexual communication traits. Rapid radiation of a sexual behaviour used in signalling, song pulse rate, has been observed in the Hawaiian cricket genus Laupala. Using marker-assisted introgression, we isolated five known quantitative trait loci (QTL) influencing species-level differences in pulse rate from one species, L. paranigra, into a closely related species, L. kohalensis. All five QTL were found to have a significant effect on song and appear to be largely additive in backcross introgression lines. Furthermore, all effect sizes were small in magnitude. Our data provide support for the hypothesis that stabilizing selection on sexual signals in Laupala creates genetic conditions favourable to incremental divergence during speciation, through the evolution of alleles of minor rather than major phenotypic effects.

Cytonuclear conflict in interpopulation hybrids: the role of RNA polymerase in mtDNA transcription and replication.

Organismal fitness requires functional integration of nuclear and mitochondrial genomes. Structural and regulatory elements coevolve within lineages and several studies have found that interpopulation hybridization disrupts mitonuclear interactions. Because mitochondrial RNA polymerase (mtRPOL) plays key roles in both mitochondrial DNA (mtDNA) replication and transcription, the interaction between mtRPOL and coevolved regulatory sites in the mtDNA may be central to mitonuclear integration. Here, we generate interpopulation hybrids between divergent populations of the copepod Tigriopus californicus to obtain lines having different combinations of mtRPOL and mtDNA. Lines were scored for mtDNA copy number and ATP6 (mtDNA) gene expression. We find that there is a genotype-dependent negative association between mitochondrial transcriptional response and mtDNA copy number. We argue that an observed increase in mtDNA copy number and reduced mtDNA transcription in hybrids reflects the regulatory role of mtRPOL; depending on the mitonuclear genotype, hybridization may disrupt the normal balance between transcription and replication of the mitochondrial genome.

Integrating (Q)SAR models, expert systems and read-across approaches for the prediction of developmental toxicity.

It has been estimated that reproductive and developmental toxicity tests will account for a significant proportion of the testing costs associated with REACH compliance. Consequently, the use of alternative methods to predict developmental toxicity is an attractive prospect. The present study evaluates a number of computational models and tools which can be used to aid assessment of developmental toxicity potential. The performance and limitations of traditional (quantitative) structure-activity relationship ((Q)SARs) modelling, structural alert-based expert system prediction and chemical profiling approaches are discussed. In addition, the use of category formation and read-across is also addressed. This study demonstrates the limited success of current modelling methods when used in isolation. However, the study also indicates that when used in combination, in a weight-of-evidence approach, better use may be made of the limited toxicity data available and predictivity improved. Recommendations are provided as to how this area could be further developed in the future.

Definition of the structural domain of the baseline non-polar narcosis model for Tetrahymena pyriformis.

The aim of this work was to develop a high-quality 1-octanol/water partition coefficient-dependent (log P) baseline quantitative structure-activity relationship (QSAR) for the toxicity (log IGC(50)(-1)) of classic non-polar narcotics to Tetrahymena pyriformis, and subsequently use this model to define the domain of applicability for baseline narcosis. The toxicities to T. pyriformis of 514 possible non-polar narcotics were assessed. A QSAR to predict toxicity was created from a training set of 87 classic non-polar narcotics (the saturated alcohols and ketones): log IGC(50)(-1) = 0.78 log P-2.01 (n = 87, r(2) = 0.96). This model was then used to predict the toxicity of the remaining chemicals. The chemicals from the large dataset which were poorly predicted by the model (i.e. the prediction was > +/-0.5 log units from the experimental value) were used to aid the definition of structural categories of chemicals which are not non-polar narcotics. Doing so has enabled the domain for non-polar narcosis to be defined in terms of structural categories. Defining domains of applicability for QSAR models is important if they are to be considered for making predictions of toxicity for regulatory purposes.

Hybrid breakdown and mitochondrial dysfunction in hybrids of Nasonia parasitoid wasps.

Male F(2) hybrids of the wasps Nasonia giraulti and Nasonia vitripennis suffer increased mortality during development. Previous studies suggested that the mitochondria may play an important role in this pattern of hybrid breakdown. The mitochondrial genome encodes 13 polypeptides, which are integral subunits of the oxidative phosphorylation enzyme complexes I, III, IV and V. We show that the mitochondrial ATP production rate and the efficacy of the enzyme complexes I, III and IV, but not that of the completely nuclear-encoded complex II, are reduced in F(2) hybrid males of N. giraulti and N. vitripennis. We hypothesize that nuclear-mitochondrial protein interactions in the oxidative phosphorylation pathway are disrupted in these hybrids, reducing energy generation capacity and potentially reducing hybrid fitness. Our results suggest that dysfunctional cytonuclear interactions could represent an under-appreciated post-zygotic isolation mechanism that, due to elevated evolutionary rates of mitochondrial genes, evolves very early in the speciation process.

The sorry state of F2 hybrids: consequences of rapid mitochondrial DNA evolution in allopatric populations.

Through the processes of natural selection and genetic drift, allopatric populations diverge genetically and may ultimately become reproductively incompatible. In cases of prezygotic reproductive isolation, candidate systems for speciation genes logically include genes involved in mate or gamete recognition. However, where only postzygotic isolation exists, candidate speciation genes could include any genes that affect hybrid performance. We hypothesize that because mitochondrial genes frequently evolve more rapidly than the nuclear genes with which they interact, interpopulation hybridization might be particularly disruptive to mitochondrial function. Understanding the potential impact of intergenomic (nuclear and mitochondrial) coadaptation on the evolution of allopatric populations of the intertidal copepod Tigriopus californicus has required a broadly integrative research program; here we present the results of experiments spanning the spectrum of biological organization in order to demonstrate the consequences of molecular evolution on physiological performance and organismal fitness. We suggest that disruption of mitochondrial function, known to result in a diverse set of human diseases, may frequently underlie reduced fitness in interpopulation and interspecies hybrids in animals.

Confinement and processing effects on glass transition temperature and physical aging in ultrathin polymer films: novel fluorescence measurements.

Fluorescence intensity measurements of chromophore-doped or -labeled polymers have been used for the first time to determine the effects of decreasing film thickness on glass transition temperature, T(g), the relative strength of the glass transition, and the relative rate of physical aging below T(g) in supported, ultrathin polymer films. The temperature dependence of fluorescence intensity measured in the glassy state of thin and ultrathin films of pyrene-doped polystyrene (PS), poly(isobutyl methacrylate) (PiBMA), and poly(2-vinylpyridine) (P2VP) differs from that in the rubbery state with a transition at T(g). Positive deviations from bulk T(g) are observed in ultrathin PiBMA and P2VP films on silica substrates while substantial negative deviations from bulk T(g) are observed in ultrathin PS films on silica substrates. The relative difference in the temperature dependences of fluorescence intensity in the rubbery and glassy states is usually reduced with decreasing film thickness, indicating that the strength of the glass transition is reduced in thinner films. The temperature dependence of fluorescence intensity also provides useful information on effects of processing history as well as on the degree of polymer-substrate interaction. In addition, when used as a polymer label, a mobility-sensitive rotor chromophore is demonstrated to be useful in measuring relative rates of physical aging in films as thin as 10 nm.

Influence of drug release properties of conventional solid dosage forms on the systemic exposure of highly soluble drugs.

This study was designed to theoretically investigate the influence of drug release properties, characterized by the disintegration of a solid dosage form and dissolution of drug particles, on the systemic exposure of highly soluble drugs in immediate release products. An absorption model was developed by considering disintegration of a solid dosage form, dissolution of drug particles, gastrointestinal transit flow, and intestinal absorption processes. The absorption model was linked to a conventional pharmacokinetic model to evaluate the effect of disintegration and dissolution on the peak exposure (Cmax) and total exposure of area under the curve (AUC). Numerical methods were used to solve the model equations. The simulations show that the effect of disintegration of a dosage form and dissolution of drug particles depend on the permeability of a drug, with a low-permeability drug having a greater effect. To provide similar exposure to an oral solution formulation, a solid dosage form containing a low-permeability drug would need to dissolve more rapidly than a solid dosage form containing a high-permeability drug. It was shown theoretically for poorly permeable drugs that the disintegration rate constant has to be greater than 9 hour(-1)(equivalent to approximately 90% in 30 minutes) to make both AUC and Cmax ratios higher than.9, ensuring the confidence interval of.80 to 1.25. The rapid in vitro release requirement of at least 85% dissolved in 30 minutes is sufficient for highly soluble and highly permeable drugs. However, for highly soluble and poorly permeable drugs, the appropriate in vitro release requirement seems to be 90% dissolved in 30 minutes.