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911.
912.
Tanya E. Cheeke Mitchell B. Cruzan Todd N. Rosenstiel 《Applied and environmental microbiology》2013,79(13):4078-4086
The cultivation of genetically engineered Bacillus thuringiensis toxin-expressing (Bt) maize continues to increase worldwide, yet the effects of Bt crops on arbuscular mycorrhizal fungi (AMF) in soil are poorly understood. In this field experiment, we investigated the impact of seven different genotypes of Bt maize and five corresponding non-Bt parental cultivars on AMF and evaluated plant growth responses at three different physiological time points. Plants were harvested 60 days (active growth), 90 days (tasseling and starting to produce ears), and 130 days (maturity) after sowing, and data on plant growth responses and percent AMF colonization of roots at each harvest were collected. Spore abundance and diversity were also evaluated at the beginning and end of the field season to determine whether the cultivation of Bt maize had a negative effect on AMF propagules in the soil. Plant growth and AMF colonization did not differ between Bt and non-Bt maize at any harvest period, but AMF colonization was positively correlated with leaf chlorophyll content at the 130-day harvest. Cultivation of Bt maize had no effect on spore abundance and diversity in Bt versus non-Bt plots over one field season. Plot had the most significant effect on total spore counts, indicating spatial heterogeneity in the field. Although previous greenhouse studies demonstrated that AMF colonization was lower in some Bt maize lines, our field study did not yield the same results, suggesting that the cultivation of Bt maize may not have an impact on AMF in the soil ecosystem under field conditions. 相似文献
913.
Tracey A. Willis Kieren G. Hollingsworth Anna Coombs Marie-Louise Sveen S?ren Andersen Tanya Stojkovic Michelle Eagle Anna Mayhew Paulo L. de Sousa Liz Dewar Jasper M. Morrow Christopher D. J. Sinclair John S. Thornton Kate Bushby Hanns Lochmüller Michael G. Hanna Jean-Yves Hogrel Pierre G. Carlier John Vissing Volker Straub 《PloS one》2013,8(8)
Background
Outcome measures for clinical trials in neuromuscular diseases are typically based on physical assessments which are dependent on patient effort, combine the effort of different muscle groups, and may not be sensitive to progression over short trial periods in slow-progressing diseases. We hypothesised that quantitative fat imaging by MRI (Dixon technique) could provide more discriminating quantitative, patient-independent measurements of the progress of muscle fat replacement within individual muscle groups.Objective
To determine whether quantitative fat imaging could measure disease progression in a cohort of limb-girdle muscular dystrophy 2I (LGMD2I) patients over a 12 month period.Methods
32 adult patients (17 male;15 female) from 4 European tertiary referral centres with the homozygous c.826C>A mutation in the fukutin-related protein gene (FKRP) completed baseline and follow up measurements 12 months later. Quantitative fat imaging was performed and muscle fat fraction change was compared with (i) muscle strength and function assessed using standardized physical tests and (ii) standard T1-weighted MRI graded on a 6 point scale.Results
There was a significant increase in muscle fat fraction in 9 of the 14 muscles analyzed using the quantitative MRI technique from baseline to 12 months follow up. Changes were not seen in the conventional longitudinal physical assessments or in qualitative scoring of the T1w images.Conclusions
Quantitative muscle MRI, using the Dixon technique, could be used as an important longitudinal outcome measure to assess muscle pathology and monitor therapeutic efficacy in patients with LGMD2I. 相似文献914.
Hanani Tabana Tanya Doherty Birgitta Rubenson Debra Jackson Anna Mia Ekstr?m Anna Thorson 《PloS one》2013,8(6)
Objective
We conducted qualitative individual and combined interviews with couples to explore their experiences since the time of taking an HIV test and receiving the test result together, as part of a home-based HIV counselling and testing intervention.Methods
This study was conducted in October 2011 in rural KwaZulu-Natal, South Africa, about 2 years after couples tested and received results together. Fourteen couples were purposively sampled: discordant, concordant negative and concordant positive couples.Findings
Learning about each other’s status together challenged relationships of the couples in different ways depending on HIV status and gender. The mutual information confirmed suspected infidelity that had not been discussed before. Negative women in discordant partnerships remained with their positive partner due to social pressure and struggled to maintain their HIV negative status. Most of the couple relationships were characterized by silence and mistrust. Knowledge of sero-status also led to loss of sexual intimacy in some couples especially the discordant. For most men in concordant negative couples, knowledge of status was an awakening of the importance of fidelity and an opportunity for behaviour change, while for concordant positive and discordant couples, it was seen as proof of infidelity. Although positive HIV status was perceived as confirmation of infidelity, couples continued their relationship and offered some support for each other, living and managing life together. Sexual life in these couples was characterized by conflict and sometimes violence. In the concordant negative couples, trust was enhanced and behaviour change was promised.Conclusions
Findings suggest that testing together as couples challenged relationships in both negative and positive ways. Further, knowledge of HIV status indicated potential to influence behaviour change especially among concordant negatives. In the discordant and concordant positive couples, traditional gender roles exposed women’s vulnerability and their lack of decision-making power. 相似文献915.
916.
David C. Pryde Thien-Duc Tran Iain Gardner Helen Bright Paul Stupple Sebastien Galan Liam Alsop Lesa Watson Donald S. Middleton Satish Dayal Michelle Platts Edward J. Murray Tanya Parkinson Robert Webster 《Bioorganic & medicinal chemistry letters》2013,23(3):827-833
Several non-benzimidazole containing inhibitors of respiratory syncytial virus are described. Core template modification, analysis of antiviral activity, physicochemistry and optimisation of properties led to the thiazole-imidazole 13, that showed a good potency and pharmacokinetic profile in the rat. 相似文献
917.
Issa N. Lyimo Daniel T. Haydon Tanya L. Russell Kasian F. Mbina Ally A. Daraja Edgar M. Mbehela Richard Reeve Heather M. Ferguson 《Proceedings. Biological sciences / The Royal Society》2013,280(1754)
Many malaria vector mosquitoes in Africa have an extreme preference for feeding on humans. This specialization allows them to sustain much higher levels of transmission than elsewhere, but there is little understanding of the evolutionary forces that drive this behaviour. In Tanzania, we used a semi-field system to test whether the well-documented preferences of the vectors, Anopheles arabiensis and Anopheles gambiae
sensu stricto (s.s.) for cattle and humans, respectively, are predicted by the fitness they obtain from host-seeking on these species relative to other available hosts. Mosquito fitness was contrasted, when humans were fully exposed and when they were protected by a typical bednet. The fitness of both vectors varied between host species. The predicted relationship between host preference and fitness was confirmed in An. arabiensis, but not in An. gambiae s.s., whose fitness was similar on humans and other mammals. Use of typical, imperfect bednets generated only minor reductions in An. gambiae s.s. feeding success and fitness on humans, but was predicted to generate a significant reduction in the lifetime reproductive success of An. arabiensis on humans relative to cows. This supports the hypothesis that such human-protective measures could additionally benefit malaria control by increasing selection for zoophily in vectors. 相似文献
918.
Tyler A. Johnson Johann Sohn Aidan E. Ward Tanya L. Cohen Nicholas D. Lorig-Roach Haixia Chen Ronaldo A. Pilli Elizabeth A. Widjaja Muhammad Hanafi Leonardus B.S. Kardono Puspa D. Lotulung Kyria Boundy-Mills Leonard F. Bjeldanes 《Bioorganic & medicinal chemistry》2013,21(14):4358-4364
An evaluation of Indonesian plants to identify compounds with immune modulating activity revealed that the methanolic extract of an Alphonsea javanica Scheff specimen possessed selective anti-inflammatory activity in a nuclear factor-kappa B (NF-κB) luciferase and MTT assay using transfected macrophage immune (Raw264.7) cells. A high-throughput LC/MS-ELSD based library approach of the extract in combination with the NF-κB and MTT assays revealed the styryl lactone (+)-altholactone (2) was responsible for the activity. Compound 2, its acetylated derivate (+)-3-O-acetylaltholactone (3), and the major compound of this class, (+)-goniothalmin (1), were further evaluated to determine their anti-inflammatory potential in the NF-κB assay. Concentration–response studies of 1–3 indicated that only 2 possessed NF-κB based anti-inflammatory activity. Compound 2 reduced the LPS-induced NO production, phosphorylation of IκBα, and the expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) using Western blot analysis. Further studies using qPCR indicated 2 reduced the expression of eight pro-inflammatory cytokines/enzymes (0.8–5.0 μM) which included: COX-2, iNOS, IP-10, IL-1β, MCP-1, GCS-F, IL-6 and IFN-β. These results indicated that 2 displays broad spectrum immune modulating activity by functioning as an anti-inflammatory agent against LPS-induced NF-κB signaling. Conversely the selective cytotoxicity and in vivo anti-tumor and anti-inflammatory activity previously reported for 1 do not appear to arise from a mechanism that is linked to the NF-κB immune mediated pathway. 相似文献
919.
Oxidative stress suppresses cysteinyl leukotriene generation by mouse bone marrow-derived mast cells
He P Laidlaw T Maekawa A Kanaoka Y Xu K Lam BK 《The Journal of biological chemistry》2011,286(10):8277-8286
Cysteinyl leukotrienes and oxidative stress have both been implicated in bronchial asthma; however, there is no previous study that focused on the ability of oxidative stress to alter cysteinyl leukotriene generation. In this study, treatment of bone marrow-derived mast cells with prostaglandin D(2) reduced their ability to generate leukotriene (LT) C(4) upon calcium ionophore stimulation but had little effect on LTB(4) generation. This effect could be reproduced by a selective agonist of the DP(2) receptor, 15R-methyl prostaglandin D(2) (15R-D(2)). 15R-D(2) dose-dependently inhibited LTC(4) generation with an IC(50) of 2 μM, and the effect was not altered by a DP(2)/thromboxane antagonist or by a peroxisome proliferator-activated receptor-γ antagonist. 15R-D(2) exerted its suppressive effect via a reduction in intracellular GSH, a mechanism that involved the conjugation of its non-enzymatic breakdown product to GSH. At 10 μM, 15R-D(2) reduced LTC(4) generation to 10%, intracellular GSH to 50%, and LTC(4) synthase (LTC(4)S) activity to 33.5% of untreated cells without altering immunoreactive LTC(4)S protein expression or 5-lipoxygenase activity. The effects of 15R-D(2) on LTC(4)S activity could be partially reversed by reducing reagent. The sulfhydryl-reactive oxidative agent diamide suppressed LTC(4)S activity and induced a reversible formation of covalent dimer LTC(4)S. LTC(4)S bearing a C56S mutation was resistant to the effect of diamide. Covalent dimer LTC(4)S was observed in nasal polyp biopsies, indicating that dimerization and inactivation of LTC(4)S can occur at the site of inflammation. These results suggest a cellular redox regulation of LTC(4)S function through a post-translational mechanism. 相似文献
920.
Matthew T. Swulius Songye Chen H. Jane Ding Zhuo Li Ariane Briegel Martin Pilhofer Elitza I. Tocheva Suzanne R. Lybarger Tanya L. Johnson Maria Sandkvist Grant J. Jensen 《Biochemical and biophysical research communications》2011,(4):149
How rod-shaped bacteria form and maintain their shape is an important question in bacterial cell biology. Results from fluorescent light microscopy have led many to believe that the actin homolog MreB and a number of other proteins form long helical filaments along the inner membrane of the cell. Here we show using electron cryotomography of six different rod-shaped bacterial species, at macromolecular resolution, that no long (>80 nm) helical filaments exist near or along either surface of the inner membrane. We also use correlated cryo-fluorescent light microscopy (cryo-fLM) and electron cryo-tomography (ECT) to identify cytoplasmic bundles of MreB, showing that MreB filaments are detectable by ECT. In light of these results, the structure and function of MreB must be reconsidered: instead of acting as a large, rigid scaffold that localizes cell-wall synthetic machinery, moving MreB complexes may apply tension to growing peptidoglycan strands to ensure their orderly, linear insertion. 相似文献