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排序方式: 共有235条查询结果,搜索用时 140 毫秒
101.
Ziwei Song Baoxin Zhang Hongqiang Feng Shiming Zhu Lingna Hu Mikkel Brydegaard Yiyun Li Samuel Jansson Elin Malmqvist Katarina Svanberg Guangyu Zhao Joakim Bood Sune Svanberg Dunsong Li 《Journal of Applied Entomology》2020,144(3):161-169
Insect pest management is a very important aspect for plant protection in crops production. Remote sensing provides a large number of techniques that are beneficial in entomological research. Although entomological radars have been used for studying migrations of insects for many years, most of entomological radar studies have been vertically tracing high-altitude migration behaviour of insects. Light detection and ranging (lidar) is a counterpart to radar, now operating in the optical part of the electromagnetic spectrum, which has been recently applied for monitoring of insects at low altitude. Such techniques, in particular low-cost continuous-wave (CW) bi-static systems based on the Scheimpflug arrangement, have been rapidly developing during the last decade. As a result, optical methods present new and fascinating possibilities. Based on experience from a 2-week field campaign in rice paddy fields, we here present an overview of lidar remote sensing applied to the Chinese scene. The capability of a CW Scheimpflug lidar system in monitoring the insects was studied. We present results on insect abundance in relation to time of the day and weather conditions. We also identified insect species by analysing wing-beat frequencies and studied their attraction to ultraviolet (UV) lamp located close to the horizontal laser sampling path during night time. Results showed that the insect species were abundant, that insects detected by the lidar system were attracted to light and that light rain increased the insect activity. The lidar detection system had a high read-out frequency, enabling the estimation of insect wing-beat frequencies. 相似文献
102.
Summary Dark respiration and photosynthetic carbon dioxide refixation in purple and green Picea abies cones were investigated from budbreak to cone maturity. The rate of dark respiration per unit dry weight and CO2 refixation capacity decreased during cone maturation. At the beginning of the growing season, photosynthetic CO2 refixation could reduce the amount of CO2 released by respiration in green and purple cones by 50% and 40%, respectively. The seasonal performance of the components of the cone carbon balance was calculated using information on the seasonal course of respiration, refixation capacity and the light response curves of cone photosynthesis, as well as the actual light and temperature regime in the field. The daily gain of CO2 refixation reached 28%–34% of respiration in green and 22%–26% in purple cones during the first month of their growth, but decreased later in the season. Over the entire growth period refixation reduced carbon costs of cone production in both cone colour polymorphs by 16%–17%. 相似文献
103.
104.
Jaana Leppälammi-Kujansuu Maija Salemaa Dan Berggren Kleja Sune Linder Heljä-Sisko Helmisaari 《Plant and Soil》2014,374(1-2):73-88
Background and aims
Increased soil temperature and nutrient availability enhance soil biological activity. We studied how these affect fine root growth and survival, i.e. below-ground litter production, in relation to above-ground foliage litter production of Norway spruce (Picea abies (L.) Karst.).Methods
The treatments, irrigation (I), soil warming + irrigation (WI), fertilization + irrigation (FI) and soil warming + fertilization + irrigation (WFI) were started in 1987 (F, I) and in 1995 (W). The annual production of fine root litter was estimated from minirhizotrons (survival) and soil-cores (biomass) and the annual above-ground litter production from litter traps.Results and conclusions
The number and elongation of fine roots tended to be higher in WI and I compared to the other treatments, which may indicate nutrient shortage. Fine roots in the WFI treatment had the lowest median longevity and from three to fourfold higher below-ground litter production compared to WI, FI or I - higher soil temperature increased the litter input particularly into the mineral soil. Only fertilization increased the above-ground litter production. As warmer and more nutrient-rich soil significantly shortened the fine root lifespan and increased the litter input, the storage of carbon in boreal forest soil may increase in the future. 相似文献105.
Geometrical Membrane Curvature as an Allosteric Regulator of Membrane Protein Structure and Function
Asger Tonnesen Sune?M. Christensen Vadym Tkach Dimitrios Stamou 《Biophysical journal》2014,106(1):201-209
Transmembrane proteins are embedded in cellular membranes of varied lipid composition and geometrical curvature. Here, we studied for the first time the allosteric effect of geometrical membrane curvature on transmembrane protein structure and function. We used single-channel optical analysis of the prototypic transmembrane β-barrel α-hemolysin (α-HL) reconstituted on immobilized single small unilamellar liposomes of different diameter and therefore curvature. Our data demonstrate that physiologically abundant geometrical membrane curvatures can enforce a dramatic allosteric regulation (1000-fold inhibition) of α-HL permeability. High membrane curvatures (1/diameter ∼1/40 nm−1) compressed the effective pore diameter of α-HL from 14.2 ± 0.8 Å to 11.4 ± 0.6 Å. This reduction in effective pore area (∼40%) when combined with the area compressibility of α-HL revealed an effective membrane tension of ∼50 mN/m and a curvature-imposed protein deformation energy of ∼7 kBT. Such substantial energies have been shown to conformationally activate, or unfold, β-barrel and α-helical transmembrane proteins, suggesting that membrane curvature could likely regulate allosterically the structure and function of transmembrane proteins in general. 相似文献
106.
The gene for ISG12 (originally designated p27) was isolated as an oestrogen-induced gene. The authors undertook a comprehensive study using quantitative RT-PCR, in which we delineate the regulation of ISG12 by seven different cytokines including interferons and poly(I). poly(C) in seven human cell lines of different origin. In all cell lines ISG12 is strongly induced by IFN-alpha and only slightly by IFNgamma. Poly(I).poly(C) induces ISG12 in a cell line-dependent manner, whereas none of the other cytokines tested elicited a response. Comparing the induction pattern of ISG12 to that of 6-16 a high degree of similarity was found. The induction levels varied, however, between cell lines. 相似文献
107.
Guillaumie F Justesen SF Mutenda KE Roepstorff P Jensen KJ Thomas OR 《Carbohydrate research》2006,341(1):118-129
This work presents the optimized separation of pectin oligomers, their analysis by matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF MS), their subsequent immobilization to supports, and our initial steps towards solid-support assisted sequencing. The ambient pressure strong anion-exchange resin Source 15Q combined with ammonium formate buffer (AF) was used for the separation of unsaturated and saturated pectic oligogalacturonides (OGAs) derived from enzymatic digestion of pectin. Routinely, multi-milligram quantities of defined sizes OGAs with DPs from 5 to 19 were produced in excellent purity (>95%). Elution of OGAs followed by direct analysis of the peak fractions by MALDI-TOF MS. Purified OGAs (DP 5-7) were chemoselectively immobilized onto aminooxy-terminated polyethylene glycol polyacrylamide (PEGA) supports. Solid-phase anchoring took place at the reducing end of the oligosaccharide and resulted in the formation of an oxime linkage. The very high coupling yields confirmed the general suitability of aminooxy-PEGA resins for the immobilization of OGAs of different lengths. The OGA-functionalized PEGA supports were subsequently treated with aq TFA at 40 or 60 degrees C, and the chemical degradation products released from the support were analyzed by ESIMS. In all cases, the original OGA was degraded into smaller oligomers of various sizes down to the monomer. This work illustrates some of the basic principles underlying a strategy ultimately aimed at solid-support assisted sequencing of oligosaccharides. 相似文献
108.
Jensen JK Malmendal A Schiøtt B Skeldal S Pedersen KE Celik L Nielsen NC Andreasen PA Wind T 《The Biochemical journal》2006,399(3):387-396
The functions of the serpin PAI-1 (plasminogen activator inhibitor-1) are based on molecular interactions with its target proteases uPA and tPA (urokinase-type and tissue-type plasminogen activator respectively), with vitronectin and with endocytosis receptors of the low-density-lipoprotein family. Understanding the significance of these interactions would be facilitated by the ability to block them individually. Using phage display, we have identified the disulfide-constrained peptide motif CFGWC with affinity for natural human PAI-1. The three-dimensional structure of a peptide containing this motif (DVPCFGWCQDA) was determined by liquid-state NMR spectroscopy. A binding site in the so-called flexible joint region of PAI-1 was suggested by molecular modelling and validated through binding studies with various competitors and site-directed mutagenesis of PAI-1. The peptide with an N-terminal biotin inhibited the binding of the uPA-PAI-1 complex to the endocytosis receptors low-density-lipoprotein-receptor-related protein 1A (LRP-1A) and very-low-density-lipoprotein receptor (VLDLR) in vitro and inhibited endocytosis of the uPA-PAI-1 complex in U937 cells. We conclude that the isolated peptide represents a novel approach to pharmacological interference with the functions of PAI-1 based on inhibition of one specific molecular interaction. 相似文献
109.
Leonardo Bottolo Marc Chadeau-Hyam David I. Hastie Tanja Zeller Benoit Liquet Paul Newcombe Loic Yengo Philipp S. Wild Arne Schillert Andreas Ziegler Sune F. Nielsen Adam S. Butterworth Weang Kee Ho Rapha?le Castagné Thomas Munzel David Tregouet Mario Falchi Fran?ois Cambien B?rge G. Nordestgaard Fredéric Fumeron Anne Tybj?rg-Hansen Philippe Froguel John Danesh Enrico Petretto Stefan Blankenberg Laurence Tiret Sylvia Richardson 《PLoS genetics》2013,9(8)
Genome-wide association studies (GWAS) yielded significant advances in defining the genetic architecture of complex traits and disease. Still, a major hurdle of GWAS is narrowing down multiple genetic associations to a few causal variants for functional studies. This becomes critical in multi-phenotype GWAS where detection and interpretability of complex SNP(s)-trait(s) associations are complicated by complex Linkage Disequilibrium patterns between SNPs and correlation between traits. Here we propose a computationally efficient algorithm (GUESS) to explore complex genetic-association models and maximize genetic variant detection. We integrated our algorithm with a new Bayesian strategy for multi-phenotype analysis to identify the specific contribution of each SNP to different trait combinations and study genetic regulation of lipid metabolism in the Gutenberg Health Study (GHS). Despite the relatively small size of GHS (n = 3,175), when compared with the largest published meta-GWAS (n>100,000), GUESS recovered most of the major associations and was better at refining multi-trait associations than alternative methods. Amongst the new findings provided by GUESS, we revealed a strong association of SORT1 with TG-APOB and LIPC with TG-HDL phenotypic groups, which were overlooked in the larger meta-GWAS and not revealed by competing approaches, associations that we replicated in two independent cohorts. Moreover, we demonstrated the increased power of GUESS over alternative multi-phenotype approaches, both Bayesian and non-Bayesian, in a simulation study that mimics real-case scenarios. We showed that our parallel implementation based on Graphics Processing Units outperforms alternative multi-phenotype methods. Beyond multivariate modelling of multi-phenotypes, our Bayesian model employs a flexible hierarchical prior structure for genetic effects that adapts to any correlation structure of the predictors and increases the power to identify associated variants. This provides a powerful tool for the analysis of diverse genomic features, for instance including gene expression and exome sequencing data, where complex dependencies are present in the predictor space. 相似文献
110.
Justesen US Pedersen C Klitgaard NA 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》2003,783(2):491-500
A simple HPLC method that quantitates all six currently available protease inhibitors and the nelfinavir active metabolite M8 in one assay is presented. A 500-microliter plasma sample was treated by liquid-liquid extraction with a mixture of heptane and ethyl acetate. After evaporation, the residue was redissolved in sodium dihydrogenphosphate and acetonitrile and washed twice with heptane. Chromatography was performed with an analytical C(18) column. Ultraviolet detection at 210 and 239 nm was used. The present method is associated with high accuracy and low imprecision in the concentration range of 25-5000 ng/ml of all six protease inhibitors and M8. This makes it suitable for monitoring purposes. 相似文献