Comparative genome and proteome analysis of Anopheles gambiae and Drosophila melanogaster     

Zdobnov EM  von Mering C  Letunic I  Torrents D  Suyama M  Copley RR  Christophides GK  Thomasova D  Holt RA  Subramanian GM  Mueller HM  Dimopoulos G  Law JH  Wells MA  Birney E  Charlab R  Halpern AL  Kokoza E  Kraft CL  Lai Z  Lewis S  Louis C  Barillas-Mury C  Nusskern D  Rubin GM  Salzberg SL  Sutton GG  Topalis P  Wides R  Wincker P  Yandell M  Collins FH  Ribeiro J  Gelbart WM  Kafatos FC  Bork P 《Science (New York, N.Y.)》2002,298(5591):149-159

Comparison of the genomes and proteomes of the two diptera Anopheles gambiae and Drosophila melanogaster, which diverged about 250 million years ago, reveals considerable similarities. However, numerous differences are also observed; some of these must reflect the selection and subsequent adaptation associated with different ecologies and life strategies. Almost half of the genes in both genomes are interpreted as orthologs and show an average sequence identity of about 56%, which is slightly lower than that observed between the orthologs of the pufferfish and human (diverged about 450 million years ago). This indicates that these two insects diverged considerably faster than vertebrates. Aligned sequences reveal that orthologous genes have retained only half of their intron/exon structure, indicating that intron gains or losses have occurred at a rate of about one per gene per 125 million years. Chromosomal arms exhibit significant remnants of homology between the two species, although only 34% of the genes colocalize in small "microsyntenic" clusters, and major interarm transfers as well as intra-arm shuffling of gene order are detected.  相似文献   

Glutamatergic and dopaminergic neurons mediate anxiogenic and anxiolytic effects of CRHR1     

Refojo D  Schweizer M  Kuehne C  Ehrenberg S  Thoeringer C  Vogl AM  Dedic N  Schumacher M  von Wolff G  Avrabos C  Touma C  Engblom D  Schütz G  Nave KA  Eder M  Wotjak CT  Sillaber I  Holsboer F  Wurst W  Deussing JM 《Science (New York, N.Y.)》2011,333(6051):1903-1907

The corticotropin-releasing hormone receptor 1 (CRHR1) critically controls behavioral adaptation to stress and is causally linked to emotional disorders. Using neurochemical and genetic tools, we determined that CRHR1 is expressed in forebrain glutamatergic and γ-aminobutyric acid-containing (GABAergic) neurons as well as in midbrain dopaminergic neurons. Via specific CRHR1 deletions in glutamatergic, GABAergic, dopaminergic, and serotonergic cells, we found that the lack of CRHR1 in forebrain glutamatergic circuits reduces anxiety and impairs neurotransmission in the amygdala and hippocampus. Selective deletion of CRHR1 in midbrain dopaminergic neurons increases anxiety-like behavior and reduces dopamine release in the prefrontal cortex. These results define a bidirectional model for the role of CRHR1 in anxiety and suggest that an imbalance between CRHR1-controlled anxiogenic glutamatergic and anxiolytic dopaminergic systems might lead to emotional disorders.  相似文献   

A spatially explicit height�Cdiameter model for Scots pine in Estonia     

Matthias Schmidt  Andres Kiviste  Klaus von Gadow 《European Journal of Forest Research》2011,130(2):303-315

This contribution presents an approach to model individual tree height?Cdiameter relationships for Scots pine (Pinus sylvestris) in multi-size and mixed-species stands in Estonia using the Estonian Permanent Forest Research Plot Network. The dataset includes 22,347 trees. The main focus of the study was to use an approach that is spatially explicit allowing for high accuracy prediction from a minimum set of predictor variables that can be easily derived. Consequently, the height?Cdiameter relationship is modeled as a function of only the stand quadratic mean diameter (dg) and the plot geographical coordinates. A specific generalized additive model gam is employed that allows for the integration of a varying coefficient term and 2-dimensional surface estimators representing a spatial trend and a spatially varying coefficient term. The high flexibility of the model is needed due to the very few predictor variables that subsume a variety of potential influential factors. Subsequently, a linear mixed model is used that quantifies the random variation between plots and between measurement occasions within plots, respectively. Hence, our model is based on the theory of structured additive regression models (Fahrmeir et al. 2007) and separates a structured (correlated) spatial effect from an unstructured (uncorrelated) spatial effect. Additionally, the linear mixed model allows for calibration of the model using height measurements as pre-information. Model bias is small, despite the somewhat irregular distribution of experimental areas within the country. The overall model shows some similarity with earlier applications in Finland. However, there are important differences involving the model form, the predictors and the method of parameter estimation.  相似文献   

Relating genetic variation of ecologically important tree traits to associated organisms in full-sib aspen families     

Frauke Kleemann  Maximilian von Fragstein  Barbara Vornam  Annika Müller  Christoph Leuschner  Andrea Holzschuh  Teja Tscharntke  Reiner Finkeldey  Andrea Polle 《European Journal of Forest Research》2011,130(5):707-716

Knowledge on phenological, morphometric, and phytochemical variation of local progenies of European aspen (Populus tremula, L.) is limited. The goal of this study was to characterize variation in growth and ecologically important leaf properties in aspen full-sib families in relation to interacting organisms (mycorrhiza, endophytes, and insects) and to determine whether these interactions were affected by soil application of a systemic fungicide. In local progenies, within-family variation of neutral molecular genetic markers (nuclear microsatellites) was higher than between families. Significant variation in growth, production of phenolic defensive compounds and other phytochemical leaf traits was found between families. Phenolic compounds showed clear negative correlation with generalist herbivores, but did not result in negative trade-off with biomass production. Differences in mycorrhizal colonization were not found among full-sib families and application of a systemic fungicide suppressed neither mycorrhizal colonization nor infestation with insects. However, a strong suppression of endophytes occurred, whose long-term consequences may require attention when fungicides are used in agroforestry plantations.  相似文献   

Fusarium oxysporum- und F. proliferatum-Isolate aus Spargel und deren Pathogenit?ts��berpr��fung in einer modifizierten in vitro-Schnelltestmethode     

Monika Go?mann  Alexandra Scholz  Frank Hennig  Susanne von Bargen  Carmen B��ttner 《Gesunde Pflanzen》2011,63(4):175-182

Fusarium oxysporum and Fusarium proliferatum are important causal agents of crown and root rot of asparagus. In order to detect differences in pathogenicity and aggressiveness, two F. proliferatum and five F. oxysporum single spore isolates from asparagus spears from plantings in Austria and Germany, 55 pure cultures of F. oxysporum from asparagus roots from a planting in Hesse, Germany, and a single F. oxysporum isolate from an asparagus shoot collected in Austria were evaluated in a 28-day quick test on Hoagland??s agar in glass culture tubes. Plantlets were inoculated with spore suspensions from each respective isolate after 14 days of growth under sterile, controlled conditions in a growth chamber. A severity scale was used to assess symptoms on roots two weeks after inoculation. The effects of the single-spore isolates on root and shoot fresh weights of the plantlets were also determined. The pathogenicity of the majority of the F. proliferatum and F. oxysporum isolates included in this study was confirmed. Inoculation with pure and single-spore cultures resulted in elevated disease severity in comparison to non-inoculated controls. In particular, the two F. proliferatum isolates were found to be more aggressive than the F. oxysporum isolates. Moreover, all single spore isolates caused a reduction in fresh weight of roots and shoots in comparison to the controls. With respect to differences among asparagus cultivars, ??Ramos??, was found to be more susceptible than ??Ravel??. Overall, the quick test method was found to be capable of evaluating the pathogenicity and aggressiveness of the tested F. oxysporum and F. proliferatum isolates towards asparagus within 28 days.  相似文献   

SOM fractionation methods: Relevance to functional pools and to stabilization mechanisms   总被引：2，自引：0，他引：2  

Margit von Lützow  Ingrid Kögel-Knabner  Heinz Flessa  Egbert Matzner 《Soil biology & biochemistry》2007,39(9):2183-2207

Soil organic matter (SOM) consists of various functional pools that are stabilized by specific mechanisms and have certain turnover rates. For the development of mechanistic models that predict changes in SOM storage, these pools have to be quantified and characterized. In the past, numerous fractionation schemes have been developed to separate and analyse such SOM fractions. In this review, the SOM fractions obtained with such operational fractionation procedures are described in terms of their pool sizes, chemical properties, and turnover rates. The main objective of this review is to evaluate these operationally defined fractions with respect to their suitability to describe functional SOM pools that could be used to parameterize SOM turnover models. Fractionation procedures include (1) physical separation of SOM into aggregate, particle size, and density fractions and fractions according to their magnetic susceptibility, and (2) various wet chemical procedures that fractionate SOM according to solubility, hydrolysability, and resistance to oxidation or by destruction of the mineral phase. Furthermore, combinations of fractionation methods are evaluated.The active SOM pool with turnover rates <10 years may best be represented by the soil microbial biomass and the light fraction (<1.6-2 g cm⁻³) obtained by density fractionation (if black carbon contents are considered). Most chemical and physical fractionations as well as combinations of methods yield SOM fractions that are not homogeneous in terms of turnover rates. It has proven to be particularly difficult to isolate functional fractions that represent the passive model pools in which the majority of soil SOM is stabilized. The available fractionation methods do not correspond to specific stabilization mechanisms and hence do not describe functional SOM pools. Another problem is that comprehensive data for turnover rates and data for whole soil profiles are only now becoming available, especially for new fractionation methods. Such information as well as the use of specific markers and compound-specific isotope analysis may be important for future differentiation and evaluation of functional SOM fractions.  相似文献   

Fluxes of CO₂, CH₄ and N₂O from drained organic soils in deciduous forests     

K. von Arnold  M. Nilsson  P. Weslien 《Soil biology & biochemistry》2005,37(6):1059-1071

We examined net greenhouse gas exchange at the soil surface in deciduous forests on soils with high organic contents. Fluxes of CO₂, CH₄ and N₂O were measured using dark static chambers for two consecutive years in three different forest types; (i) a drained and medium productivity site dominated by birch, (ii) a drained and highly productive site dominated by alder and (iii) an undrained and highly productive site dominated by alder. Although the drained sites had shallow mean groundwater tables (15 and 18 cm, respectively) their average annual rates of forest floor CO₂ release were almost twice as high compared to the undrained site (1.9±0.4 and 1.7±0.3, compared to 1.0±0.2 kg CO₂ m⁻² yr⁻¹). The average annual CH₄ emission was almost 10 times larger at the undrained site (7.6±3.1 compared to 0.9±0.5 g CH₄ m⁻² yr⁻¹ for the two drained sites). The average annual N₂O emissions at the undrained site (0.1±0.05 g N₂O m⁻² yr⁻¹) were lower than at the drained sites, and the emissions were almost five times higher at the drained alder site than at the drained birch site (0.9±0.35 compared to 0.2±0.11 g N₂O m⁻² yr⁻¹). The temporal variation in forest floor CO₂ release could be explained to a large extent by differences in groundwater table and air temperature, but little of the variation in the CH₄ and N₂O fluxes could be explained by these variables. The measured soil variables were only significant to explain for the within-site spatial variation in CH₄ and N₂O fluxes at the undrained swamp, and dark forest floor CO₂ release was not explained by these variables at any site. The between-site spatial variation was attributed to variations in drainage, groundwater level position, productivity and tree species for all three gases. The results indicate that N₂O emissions are of greater importance for the net greenhouse gas exchange at deciduous drained forest sites than at coniferous drained forest sites.  相似文献   

Seasonal effects of liming,irrigation, and acid precipitation on microbial biomass N in a spruce (Picea abies L.) forest soil     

M. von Lützow  L. Zelles  I. Scheunert  J. C. G. Ottow 《Biology and Fertility of Soils》1992,13(3):130-134

Summary Seasonal effects of liming, irrigation, and acid precipitation on microbial biomass N and some physicochemical properties of different topsoil horizons in a spruce forest (Picea abies L.) were measured throughout one growing season. The highest biomass N was recorded in autumn and spring in the upper soil horizons, while the lowest values were obtained in summer and in deeper horizons. The clearest differences between the different soil treatments were apparent in autumn and in the upper horizons. Liming increased the microbial biomass N from 1.7% of the total N content to 6.8% (Olf₁ layer) and from 1% to 2% of the total N content in the Of₂ layer. The main inorganic-N fraction in the deeper horizons was NO _inf3 ^sup- . An increase in cation exchange capacity was observed down to the Oh layer, while soil pH was only slightly higher in the Olf₁ and Of₂ layers after liming. The effects of irrigation were less marked. The microbial biomass N increased from 1.7% of total N to 4.8% in the Olf₁ layer and from 1% to 2% of total N in the Of₂ layer. In the Olf₁ layer an increase in C mineralization was observed. Acid precipitation decreased the microbial biomass N in the upper horizons from 4.8% of total N to 1.8% in the Olf₁ layer and from 2% to 0.5% in the Of₂ layer. No significant changes in soil pH were observed, but the decrease in cation exchange capacity may result in a decrease in the proton buffering capacity in the near future.  相似文献   

Dust levels and control methods in poultry houses   总被引：1，自引：0，他引：1  

Ellen HH  Bottcher RW  von Wachenfelt E  Takai H 《Journal of agricultural safety and health》2000,6(4):275-282

This article summarizes information from the papers and posters presented at the international symposium on "Dust Control in Animal Production Facilities", held in Aarhus (Denmark) on 30 May-2 June 1999. Dust concentrations in poultry houses vary from 0.02 to 81.33 mg/m3 for inhalable dust and from 0.01 to 6.5 mg/m3 for respirable dust. Houses with caged laying hens showed the lowest dust concentrations, i.e., less than 2 mg/m3, while the dust concentrations in the other housing systems, e.g., perchery and aviary systems, were often four to five times higher. Other factors affecting the dust concentrations are animal category, animal activity, bedding materials and season. The most important sources of dust seem to be the animals and their excrements. Further studies on the effects of housing systems on dust sources and their compounds are desired for development of a healthier working environment in poultry production facilities. Adjustment of the relative humidity (RH) of the air in a broiler house to 75% will have an effect on inhalable dust, but not on respirable dust. A slight immediate effect on the respirable dust was observed after fogging with pure water or water with rapeseed oil. In an aviary system, a 50 to 65% reduction of the inhalable dust concentration was found after spraying water with 10% of oil and pure water, respectively. To obtain a higher dust reducing efficiency, improvement of techniques for application of droplets onto dust sources will be desired.  相似文献   

Vitisin A content in Chilean wines from Vitis vinifera Cv. Cabernet Sauvignon and contribution to the color of aged red wines     

Schwarz M  Quast P  von Baer D  Winterhalter P 《Journal of agricultural and food chemistry》2003,51(21):6261-6267

Vitisin A was prepared from malvidin 3-glucoside and pyruvic acid in model wine medium, isolated by countercurrent chromatography, and purified by preparative high-performance liquid chromatography (HPLC). The synthesized compound was used as a reference standard to quantify vitisin A in Chilean wines from Vitis vinifera cv. Cabernet Sauvignon, including a vertical row of wines from the same vineyard over 16 years. Maximum vitisin A content was reached within the first year of storage. Importantly, up to half of the initial amount of vitisin A in young wines was still present in 15 year old wines. Although vitisin A was found to be much more stable as compared to other monomeric C-4 underivatized anthocyanins, it also slowly degrades after reaching its peak concentration. The "color activity concept" was applied to vitisin A, malvidin 3-glucoside, malvidin 3-(6' '-acetylglucoside), and polymeric pigments isolated by countercurrent chromatography in order to estimate their contribution toward the overall color expression of wines. It was found that vitisin A is only a minor contributor to the visually perceived color of aged red wines (color contribution approximately 5%). The major contributor is the polymeric fraction (color contribution approximately 70-90%).  相似文献