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101.
This review summarises recent investigations into the molecular mechanisms responsible for the decline in sensitivity to azole (imidazole and triazole) fungicides in European populations of the Septoria leaf blotch pathogen, Mycosphaerella graminicola. The complex recent evolution of the azole target sterol 14α‐demethylase (MgCYP51) enzyme in response to selection by the sequential introduction of progressively more effective azoles is described, and the contribution of individual MgCYP51 amino acid alterations and their combinations to azole resistance phenotypes and intrinsic enzyme activity is discussed. In addition, the recent identification of mechanisms independent of changes in MgCYP51 structure correlated with novel azole cross‐resistant phenotypes suggests that the further evolution of M. graminicola under continued selection by azole fungicides could involve multiple mechanisms. The prospects for azole fungicides in controlling European M. graminicola populations in the future are discussed in the context of these new findings. Copyright © 2012 Society of Chemical Industry 相似文献
102.
103.
Willem M Garratt AN Novak B Citron M Kaufmann S Rittger A DeStrooper B Saftig P Birchmeier C Haass C 《Science (New York, N.Y.)》2006,314(5799):664-666
Although BACE1 (beta-site amyloid precursor protein-cleaving enzyme 1) is essential for the generation of amyloid-b peptide in Alzheimer's disease, its physiological function is unclear. We found that very high levels of BACE1 were expressed at time points when peripheral nerves become myelinated. Deficiency of BACE1 resulted in the accumulation of unprocessed neuregulin 1 (NRG1), an axonally expressed factor required for glial cell development and myelination. BACE1-/- mice displayed hypomyelination of peripheral nerves and aberrant axonal segregation of small-diameter afferent fibers, very similar to that seen in mice with mutations in type III NRG1 or Schwann cell-specific ErbB2 knockouts. Thus, BACE1 is required for myelination and correct bundling of axons by Schwann cells, probably through processing of type III NRG1. 相似文献
104.
de Rijke E Ruisch B Bakker J Visser J Leenen J Haiber S de Klerk A Winkel C König T 《Journal of agricultural and food chemistry》2007,55(16):6417-6423
In this study a specific taste modulating flavor ingredient, N-lactoylguanosine 5'-monophosphate (N-lactoyl GMP), was determined in bonito (Japanese, Katsuobushi, dried fermented skipjack) and in powdered bonito using liquid chromatography-electrospray ionization (+) mass spectrometry-mass spectrometry (LC-ESI(+)-MS/MS) with a methanol/ammonium acetate or formate gradient. Furthermore, the influence of ion suppression due to sample matrix effect was investigated and was found to substantially influence the total MS response of N-lactoyl GMP; by adjusting the LC conditions the response could be approximately 5-fold-enhanced. The N-lactoyl GMP concentrations in different types of bonito products were between 0.2 and 2.4 microg/g. 相似文献
105.
Currently, the driving factors of active earthworm dispersal across the soil surface are not sufficiently understood, and distances traversed by individual earthworms have rarely been quantified. Research progress has been hampered by the lack of adequate observation methods as well as fast, objective and quantitative measurements of nocturnal earthworm behaviour.In this work, we report on the potential of a new, automated method using infrared-sensitive webcams and computer image analysis. Nightly surface activities of Lumbricus terrestris L. were monitored quantitatively while manipulating levels of disturbance, burrow availability and congener presence in standard observation units.The automated observation system proved to be simple and inexpensive to build, provided reliable quantitative measures of locomotive behaviour without animal disturbance, and considerably reduced human workload and bias.Waterlogging of the burrow zone stimulated surface activities around and away from the home burrow as compared to habitat disturbance by pesticide application and vibration. However, dispersing earthworms never settled in prefabricated burrows. Surface activity of individuals subjected to waterlogged conditions was influenced by the availability of alternative habitat. Minimal habitat disturbance (vibration) and the presence of conspecific individuals resulted in an increased amount of burrow-anchored, possibly sexually oriented, behaviour, but reciprocal burrow visits and mating were not observed. Pesticide application did not result in dispersal, increased foraging activities or sexual attraction attempts during this short-term study.The presence, extent and mechanisms of the remote assessment of important cues in the surroundings of the home burrow by L. terrestris need further research. Infrared monitoring opens new research avenues of earthworm surface behaviour studies (e.g. density-dependent dispersal, habitat selection, (re)colonization, invasion). 相似文献
106.
107.
Summary Calli of resistant, intermediary and susceptible wheat (Triticum aestivum L.) varieties were selected using culture filtrates of Fusarium graminearum and F. culmorum and the regenerants were evaluated for resistance up to R3. Czapek-Dox broth medium was inoculated with mycelia of Fusarium isolates and incubated for 2–6 weeks. Filtrates were added to MS callus growing medium, then 5 weeks-old calli were transferred onto this medium (MST) for 4–5 weeks. MST containing 30% filtrate was found to be suitable for selection. Resistant calli were transferred again to fresh MST for further two selection cycles. The surviving calli produced less fertile regenerated lines (R0) than the non-selected ones. Among 18 R1 lines tested for Fusarium-resistance in the seedling stage by artificial inoculation in the greenhouse, two (11.1%) were significantly more resistant, one (5.6%) was more susceptible than the original cultivar and the rest (83.3%) behaved similarly to the donor plants. Among unselected R3 lines of three varieties, practically the same number of resistant plants were found as among the related selected ones. When the R3 selfed generations obtained through double-layer and culture filtrate selection techniques were tested for Fusarium-resistance, 35.7% of the lines were found to be more resistant than the original cultivars, none was more susceptible and 64.3% had a reaction similar to that of the source materials. Thus, inheritance of the disease reaction was not stable in all cases. Success of in vitro selection for Fusarium-resistance depended also on the genotype, and toxin analysis showed that although being effective, the selective media contained deoxynivalenol only exceptionally. In selecting wheat for Fusarium-resistance in vitro, the culture filtrate technique proved better than the double-layer procedure. 相似文献
108.
Vanderhaegen B Neven H Coghe S Verstrepen KJ Verachtert H Derdelinckx G 《Journal of agricultural and food chemistry》2003,51(23):6782-6790
The aging and consequent changes in flavor molecules of a top-fermented beer were studied. Different aging conditions were imposed on freshly bottled beer. After 6 months of aging, the concentration changes were recorded for acetate esters, ethyl esters, carbonyls, Maillard compounds, dioxolanes, and furanic ethers. For some flavor compounds, the changes with time of storage were monitored at different temperatures, either with CO(2) or with air in the headspace of the bottles. For some molecules a relationship was determined between concentration changes and sensory evaluation results. A decrease in volatile esters was responsible for a reduced fruity flavor during aging. On the contrary, various carbonyl compounds, some ethyl esters, Maillard compounds, dioxolanes, and furanic ethers showed a marked increase, due to oxidative and nonoxidative reactions. A very high increase was found for furfural, 2-furanmethanol, and especially the furanic ether, 2-furfuryl ethyl ether (FEE). For FEE a flavor threshold in beer of 6 mug/L was determined. In the aged top-fermented beer, FEE concentrations multiple times the flavor threshold were observed. This was associated with the appearance of a typical solvent-like flavor. As the FEE concentration increased with time at an almost constant rate, with or without air in the headspace, FEE (and probably other furanic ethers) is proposed as a good candidate to evaluate the thermal stress imposed on beer. 相似文献
109.
Hans J. M. van Grinsven Bart G. Wesselink Manfred Schroeder Nico van Breemen 《植物养料与土壤学杂志》1991,154(3):181-188
Solute budgets and nitrogen use were quantified in two 400 m2 forested lysimeters in St. Arnold, Nordrhein-Westfalen. The lysimeters are covered by a mixture of oak-beech and Weymouth pine, respectively. The average bulk deposition between May 1985 and May 1987 of NH, SO and NO3 was 1.1, 1.7, and 0.4 kmolc ha?1 yr?1 in the deciduous stand and 2.1, 2.1, and 0.8 kmolc ha?1 yr?1 in the coniferous stand. The input of N is almost completely retained in the deciduous stand. In the coniferous stand about 30% of this N-input is leached as NO3. Due to N-transformations, total proton turnover is 4.4 kmolc ha?1 yr?1 in the coniferous stand and only 2.5 kmolc ha?1 yr?1 in the deciduous stand. Ca-mobilization is the major acid buffering process in both lysimeters. Only the deciduous stand was limed in 1980 (90 kmolc/ha). Mobilization of Al is only relevant down to a soil depth of 30 cm. Below a 30 cm depth, Al is immobilized. The amounts of exchangeable and silicate-bound Ca in the soil underlying the coniferous stand are very small, but no evidence was found for explanation of the observed high Ca-mobilization by artificial Ca-sources. 相似文献
110.
Tree species selection for land rehabilitation in Ethiopia: from fragmented knowledge to an integrated multi-criteria decision approach 总被引:1,自引:1,他引:0
Bert Reubens Clara Moeremans Jean Poesen Jan Nyssen Sarah Tewoldeberhan Steve Franzel Jozef Deckers Caleb Orwa Bart Muys 《Agroforestry Systems》2011,82(3):303-330
Dryland regions worldwide are increasingly suffering from losses of soil and biodiversity as a consequence of land degradation.
Integrated conservation, rehabilitation and community-based management of natural resources are therefore of vital importance.
Local planting efforts should focus on species performing a wide range of functions. Too often however, unsuitable tree species
are planted when both ecological suitability for the targeted area or preferences of local stakeholders are not properly taken
into account during selection. To develop a decision support tool for multi-purpose species selection, first information needs
to be pooled on species-specific ranges, characteristics and functions for a set of potentially valuable species. In this
study such database has been developed for the highly degraded northern Ethiopian highlands, using a unique combination of
information sources, and with particular attention for local ecological knowledge and preferences. A set of candidate tree
species and potentially relevant criteria, a flexible input database with species performance scores upon these criteria,
and a ready-to-use multi-criteria decision support tool are presented. Two examples of species selection under different scenarios
have been worked out in detail, with highest scores obtained for Cordia africana and Dodonaea angustifolia, as well as Eucalyptus spp., Acacia abyssinica, Acacia saligna, Olea europaea and Faidherbia albida. Sensitivity to criteria weights, and reliability and lack of knowledge on particular species attributes remain constraints
towards applicability, particularly when many species are jointly evaluated. Nonetheless, the amount and diversity of the
knowledge pooled in the presented database is high, covering 91 species and 45 attributes. 相似文献