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81.
Background and purpose
Rapid increases in atmospheric carbon dioxide concentration ([CO2]) may increase crop residue production and carbon: nitrogen (C:N) ratio. Whether the incorporation of residues produced under elevated [CO2] will limit soil N availability and fertilizer N recovery in the plant is unknown. This study investigated the interaction between crop residue incorporation and elevated [CO2] on the growth, grain yield and the recovery of 15N-labeled fertilizer by wheat (Triticum aestivum L. cv. Yitpi) under controlled environmental conditions.Methods
Residue for ambient and elevated [CO2] treatments, obtained from wheat grown previously under ambient and elevated [CO2], respectively, was incorporated into two soils (from a cereal-legume rotation and a cereal-fallow rotation) 1 month before the sowing of wheat. At the early vegetative stage 15N-labeled granular urea (10.22 atom%) was applied at 50 kg?N ha?1 and the wheat grown to maturity.Results
When residue was not incorporated into the soil, elevated [CO2] increased wheat shoot (16 %) and root biomass (41 %), grain yield (19 %), total N uptake (4 %) and grain N removal (8 %). However, the positive [CO2] fertilization effect on these parameters was absent in the soil amended with residue. In the absence of residue, elevated [CO2] increased fertilizer N recovery in the plant (7 %), but when residue was incorporated elevated [CO2] decreased fertilizer N recovery.Conclusions
A higher fertilizer application rate will be required under future elevated [CO2] atmospheres to replenish the extra N removed in grains from cropping systems if no residue is incorporated, or to facilitate the [CO2] fertilization effect on grain yield by overcoming N immobilization resulting from residue amendment. 相似文献82.
Marco I. Ries Hazrat Ali Peter P. Lankhorst Thomas Hankemeier Roel A. L. Bovenberg Arnold J. M. Driessen Rob J. Vreeken 《The Journal of biological chemistry》2013,288(52):37289-37295
Metabolic profiling and structural elucidation of novel secondary metabolites obtained from derived deletion strains of the filamentous fungus Penicillium chrysogenum were used to reassign various previously ascribed synthetase genes of the roquefortine/meleagrin pathway to their corresponding products. Next to the structural characterization of roquefortine F and neoxaline, which are for the first time reported for P. chrysogenum, we identified the novel metabolite roquefortine L, including its degradation products, harboring remarkable chemical structures. Their biosynthesis is discussed, questioning the exclusive role of glandicoline A as key intermediate in the pathway. The results reveal that further enzymes of this pathway are rather unspecific and catalyze more than one reaction, leading to excessive branching in the pathway with meleagrin and neoxaline as end products of two branches. 相似文献
83.
Christophe Blanchetot Dennis Verzijl Azra Muji?-Deli? Leontien Bosch Louise Rem Rob Leurs C. Theo Verrips Michael Saunders Hans de Haard Martine J. Smit 《The Journal of biological chemistry》2013,288(35):25173-25182
Chemokine receptors and their ligands play a prominent role in immune regulation but many have also been implicated in inflammatory diseases such as multiple sclerosis, rheumatoid arthritis, allograft rejection after transplantation, and also in cancer metastasis. Most approaches to therapeutically target the chemokine system involve targeting of chemokine receptors with low molecular weight antagonists. Here we describe the selection and characterization of an unprecedented large and diverse panel of neutralizing Nanobodies (single domain camelid antibodies fragment) directed against several chemokines. We show that the Nanobodies directed against CCL2 (MCP-1), CCL5 (RANTES), CXCL11 (I-TAC), and CXCL12 (SDF-1α) bind the chemokines with high affinity (at nanomolar concentration), thereby blocking receptor binding, inhibiting chemokine-induced receptor activation as well as chemotaxis. Together, we show that neutralizing Nanobodies can be selected efficiently for effective and specific therapeutic treatment against a wide range of immune and inflammatory diseases. 相似文献
84.
P. Jyothsna Q. M. I. Haq Priyanka Singh K. V. Sumiya Shelly Praveen Ramaveer Rawat Rob W. Briddon V. G. Malathi 《Applied microbiology and biotechnology》2013,97(12):5457-5471
Tomato leaf curl New Delhi virus (ToLCNDV) (Geminiviridae) is an important pathogen that severely affects tomato production. An extensive survey was carried out during 2003–2010 to study the diversity of begomoviruses found in tomato, potato, and cucurbits that showed symptoms of leaf puckering, distortion, curling, vein clearing, and yellow mosaic in various fields in different regions of India. Ten begomovirus isolates were cloned from infected samples and identified as belonging to the species ToLCNDV. A total of 44 % of the samples showed association of betasatellites, with CLCuMuB and LuLDB being the most frequent. The ToLCNDV cloned component DNA A and DNA B were agroinoculated on Nicotiana benthamiana and tomato (Solanum lycopersicum) plants with or without betasatellites, CLCuMuB or LuLDB. The viral genome levels were then monitored by real-time polymerase chain reaction at different time points of disease development. Plants co-inoculated with betasatellites showed enhanced symptom severity in both N. benthamiana and tomato, as well as increases in helper viral DNA A and DNA B levels. The DNA B and betasatellites acted antagonistically to each other, so that the level of DNA B was 16-fold greater in the presence of betasatellites, while accumulation of betasatellites, CLCuMuB and LuLDB, were reduced by 60 % in the presence of DNA B. DNA B-mediated symptoms predominated in CLCuMuB-inoculated plants, whereas betasatellite-mediated leaf abnormalities were prominent in LuLDB-co-inoculated plants. Inoculation with the cloned components will be a good biotechnological tool in resistance breeding program. 相似文献
85.
Robério C.S. Neves Allan T. Showler Ézio S. Pinto Cristina S. Bastos Jorge B. Torres 《Entomologia Experimentalis et Applicata》2013,146(2):276-285
Cotton pests damaging fruiting bodies (squares and young bolls) are difficult to control and their damage results in direct yield loss. Small growers, with low technological inputs, represent a large portion of cotton growers worldwide comprising more than 76 countries; they rely mainly on cultural practices to counteract pest attack in their crops. Boll weevil, Anthonomus grandis Boheman (Coleoptera: Curculionidae), oviposition involves puncturing cotton squares and young bolls, causing abscission. We examined the impact on boll weevil population of collecting abscised cotton fruiting bodies and clipping plant terminals at 50% boll maturation in the field during two cotton‐growing seasons and under field cage conditions. Greatest numbers of damaged squares occurred ca. 117 days after planting and clipped plants resulted in reduction of abscised structures and adult boll weevils compared with non‐clipped plants, irrespective of cotton variety. Damaged young bolls were found ca. 128 days after planting in 2009 and 2011, but clipping had no effect. Numbers of boll weevils found in plants of the varieties BRS 201 and BRS Rubi (both in 2009) and BRS Rubi (in 2011) were, respectively, 13‐, 17‐, and 20‐fold greater when clipping plus collecting abscised fruiting bodies were not practiced. Furthermore, the average percentage of the boll weevil parasitoid Bracon vulgaris Ashmead (Hymenoptera: Braconidae) emerging from abscised and collected structures was similar between clipped and non‐clipped plant terminals in both seasons. Clipping plant terminals did not result in yield reduction and reduced adult boll weevil production. Collecting abscised reproductive structures, clipping plant terminals, and using both practices together reduced boll weevil populations by as much as 63, 57, and 79%, respectively, in cage trials. Thus, these practices cause significant impact on boll weevil populations and are feasible of adoption, especially for smallholder cotton growers. 相似文献
86.
Upland birds are predicted to be particularly vulnerable to the effects of climate change, yet few studies have examined these effects on their breeding phenology and productivity. Laying dates of Red Grouse Lagopus lagopus scotica in the Scottish Highlands advanced by 0.5 days/year between 1992 and 2011 and were inversely correlated with pre‐laying temperature, with a near‐significant increase in temperature over this period. Earlier clutches were larger and chick survival was greater in earlier nesting attempts. However, chick survival was also higher in years with lower May temperatures and lower August temperatures in the previous year, the latter probably related to prey abundance in the subsequent breeding season. Although laying dates are advancing, climate change does not currently appear to be having an overall effect on chick survival of Red Grouse within the climate range recorded in this study. 相似文献
87.
Mounir Andaloussi Herman D. Lim Tiffany van der Meer Maarten Sijm Chris B.M. Poulie Iwan J.P. de Esch Rob Leurs Rogier A. Smits 《Bioorganic & medicinal chemistry letters》2013,23(9):2663-2670
In this work we describe the optimization of a lead compound based on the quinazoline template to give a new series of potent pyrido[3,2-d]pyrimidines as histamine H4 receptor antagonists. The pyrido[3,2-d]pyrimidine ligands have significantly reduced hERG binding compared to clinical stage compound PF-3893787 while showing good affinities at the human and rodent histamine receptors. The receptor residence time of several of these new compounds was determined for the human H4R and compared with JNJ7777120 and PF-3893787. The pyrido[3,2-d]pyrimidines showed residence times lower than JNJ7777120 but comparable to the residence time of PF-3893787. Overall, the pyrido[3,2-d]pyrimidines show an excellent in vitro profile that warrants their further investigation in relevant models of human disease. 相似文献
88.
Kristel Mijnendonckx Natalie Leys Jacques Mahillon Simon Silver Rob Van Houdt 《Biometals》2013,26(4):609-621
This review gives a comprehensive overview of the widespread use and toxicity of silver compounds in many biological applications. Moreover, the bacterial silver resistance mechanisms and their spread in the environment are discussed. This study shows that it is important to understand in detail how silver and silver nanoparticles exert their toxicity and to understand how bacteria acquire silver resistance. Silver ions have shown to possess strong antimicrobial properties but cause no immediate and serious risk for human health, which led to an extensive use of silver-based products in many applications. However, the risk of silver nanoparticles is not yet clarified and their widespread use could increase silver release in the environment, which can have negative impacts on ecosystems. Moreover, it is shown that silver resistance determinants are widely spread among environmental and clinically relevant bacteria. These resistance determinants are often located on mobile genetic elements, facilitating their spread. Therefore, detailed knowledge of the silver toxicity and resistance mechanisms can improve its applications and lead to a better understanding of the impact on human health and ecosystems. 相似文献
89.
Charlotte E. Allen Chiau L. Chow John J. Caldwell Isaac M. Westwood Rob L. M. van Montfort Ian Collins 《Bioorganic & medicinal chemistry》2013,21(18):5707-5724
With the success of protein kinase inhibitors as drugs to target cancer, there is a continued need for new kinase inhibitor scaffolds. We have investigated the synthesis and kinase inhibition of new heteroaryl-substituted diazaspirocyclic compounds that mimic ATP. Versatile syntheses of substituted diazaspirocycles through ring-closing metathesis were demonstrated. Diazaspirocycles directly linked to heteroaromatic hinge binder groups provided ligand efficient inhibitors of multiple kinases, suitable as starting points for further optimization. The binding modes of representative diazaspirocyclic motifs were confirmed by protein crystallography. Selectivity profiles were influenced by the hinge binder group and the interactions of basic nitrogen atoms in the scaffold with acidic side-chains of residues in the ATP pocket. The introduction of more complex substitution to the diazaspirocycles increased potency and varied the selectivity profiles of these initial hits through engagement of the P-loop and changes to the spirocycle conformation, demonstrating the potential of these core scaffolds for future application to kinase inhibitor discovery. 相似文献
90.
Jill M. Shephard Rob Ogden Piotr Tryjanowski Ola Olsson Peter Galbusera 《Ecology and evolution》2013,3(15):4881-4895
European white stork are long considered to diverge to eastern and western migration pools as a result of independent overwintering flyways. In relatively recent times, the western and northern distribution has been subject to dramatic population declines and country‐specific extirpations. A number of independent reintroduction programs were started in the mid 1950s to bring storks back to historical ranges. Founder individuals were sourced opportunistically from the Eastern and Western European distributions and Algeria, leading to significant artificial mixing between eastern and western flyways. Here we use mitochondrial and microsatellite DNA to test the contention that prior to translocation, eastern and western flyways were genetically distinct. The data show a surprising lack of structure at any spatial or temporal scale suggesting that even though birds were moved between flyways, there is evidence of natural mixing prior to the onset of translocation activities. Overall a high retention of genetic diversity, high Nef, and an apparent absence of recent genetic bottleneck associated with early 20th century declines suggest that the species is well equipped to respond to future environmental pressures. 相似文献