Fungal diversity in set-aide agricultural soil investigated using terminal-restriction fragment length polymorphism     

Morten Klamer  Katarina Hedlund 《Soil biology & biochemistry》2004,36(6):983-988

As part of the restoration of biodiversity on former agricultural land there has been focused on methods to enhance the rate of transition from agricultural land towards natural grasslands or forest ecosystems. Management practices such as sowing seed mixtures and inoculating soil of later successional stages have been used. The aim of this study was to determine the effects of a managed plant community on the diversity of soil fungi in a newly abandoned agricultural land. A field site was set up consisting of 20 plots where the plant diversity was managed by either sowing 15 plant species, or natural colonization was allowed to occur. The plant mixture contained five species each of grasses, legumes and forbs that all were expected to occur at the site. A subset of the plots (five from each treatment) was inoculated with soil cores from a late successional stage. The plant community composition was subject to a principal component analysis based on the coverage of each species. Five years after abandonment, soil samples were taken from the plots, DNA was extracted and the ITS region of the rDNA gene was amplified using fluorescently labelled fungal specific primers (ITS 1F/ITS 4). The PCR products were digested using HinfI and TaqI and sequenced. Results from both restriction enzymes were combined and a principal component analysis performed on the presence/absence of fragments. Also the fungal diversity expressed as number of restriction fragments were analysed. There was significantly higher fungal species richness in the experimental plots compared to the forest and field soils, but no differences between sown and naturally colonized plots. The different plant treatments did not influence the below ground fungal community composition. Soil water content on the other hand had an impact on the fungal community composition.  相似文献   

Electrochemical in situ impregnation of wood using a copper nail as source for copper     

Lisbeth M. Ottosen  Thomas Block  Morten Nymark  Iben V. Christensen 《Wood Science and Technology》2011,45(2):289-302

A new method for copper impregnation of wood in structures was suggested and tested in laboratory scale with specimen of new pine sapwood. A copper nail and a steel screw were placed in the wood, and an electric direct current field was applied, so the copper nail was anode and the screw was cathode. At the anode, copper ions were generated. The copper ions were transported into the wood by electromigration (movement of ions in an applied electric field) towards the cathode, and a volume between the two electrodes was thereby impregnated. Copper also moved to a lesser degree in the opposite direction, probably due to capillary effects, and a smaller volume behind the anode was impregnated as well. The impregnation perpendicular to the grain was limited compared to the one along the grain. The highest Cu concentrations were obtained close to the anode.  相似文献   

The Effects of Feeding Peptide-Precipitating Lignosulphonic Acids in Various Concentrations to Growing Pigs     

Bjrn Nss  Morten Fjlstad 《Acta veterinaria Scandinavica》1973,14(1):147

It is shown that lignosulphonic acids, at a concentration of 13 % in conventional feed given to growing pigs, lead to a marked reduction in the weight gain.When given 3 % and 6 % lignosulphonic acids in the feed, no effects on the weight gain were observed as compared to the controls.The weight gain reduction caused by lignosulphonic acids at high levels in the feed is discussed in relation to the inhibitory effects of these acids on a number of biological systems which have been studied previously.  相似文献   

CIMMYT人工合成小麦与普通小麦杂交后代籽粒硬度puroindoline基因等位变异检测   总被引：14，自引：3，他引：14  

陈锋  夏先春  王德森  Morten Lillemo  何中虎 《中国农业科学》2006,39(3):440-447

 【目的】山羊草与硬粒小麦杂交培育的人工合成小麦已广泛应用于国内外小麦品种改良，研究人工合成小麦与普通小麦杂交后代的籽粒硬度变异类型，有助于提高育种效率。【方法】以来自CIMMYT的176份人工合成小麦与普通小麦杂交后代为材料，采用单籽粒谷物硬度测试仪、特异引物的PCR扩增和改进的SDS-PAGE凝胶电泳对其SKCS硬度及其基因型进行了研究。【结果】硬质基因型均为Pina-D1b/Pinb-D1a类型，软质基因型有Pina-D1a/Pinb-D1a、Pina-D1j/Pinb-D1i、Pina-D1a/Pinb-D1i和Pina-D1c/Pinb-D1h等4种类型。其中Pina-D1j/Pinb-D1i是最常见的突变类型，占软质麦总数的49.1%。不同puroindoline类型的硬度比较表明，Pina-D1b/Pinb-D1a与其它类型间差异均达1%显著水平。在软质基因型中，Pina-D1c/Pinb-D1h和Pina-D1a/Pinb-D1i类型硬度相对较高，与Pina-D1j/Pinb-D1i和Pina-D1a/Pinb-D1a的籽粒硬度差异达5%显著水平。另外，Pina-D1a/Pinb-D1i的千粒重和粒径也显著高于其它变异类型。【结论】本试验发现了多种普通小麦中未曾发现过的puroindoline基因型，且硬度数值间存在显著差异，为人工合成小麦在品种改良中的应用和我国从CIMMYT引种提供了依据，同时也有助于puroindoline基因的多态性研究。  相似文献   

Control of the selectivity of the aquaporin water channel family by global orientational tuning   总被引：1，自引：0，他引：1  

Tajkhorshid E  Nollert P  Jensen MØ  Miercke LJ  O'Connell J  Stroud RM  Schulten K 《Science (New York, N.Y.)》2002,296(5567):525-530

Aquaporins are transmembrane channels found in cell membranes of all life forms. We examine their apparently paradoxical property, facilitation of efficient permeation of water while excluding protons, which is of critical importance to preserving the electrochemical potential across the cell membrane. We have determined the structure of the Escherichia coli aquaglyceroporin GlpF with bound water, in native (2.7 angstroms) and in W48F/F200T mutant (2.1 angstroms) forms, and carried out 12-nanosecond molecular dynamics simulations that define the spatial and temporal probability distribution and orientation of a single file of seven to nine water molecules inside the channel. Two conserved asparagines force a central water molecule to serve strictly as a hydrogen bond donor to its neighboring water molecules. Assisted by the electrostatic potential generated by two half-membrane spanning loops, this dictates opposite orientations of water molecules in the two halves of the channel, and thus prevents the formation of a "proton wire," while permitting rapid water diffusion. Both simulations and observations revealed a more regular distribution of channel water and an increased water permeability for the W48F/F200T mutant.  相似文献   

Guild composition and habitat use of voles in 2 forest landscapes in south‐eastern Norway     

Lucrezia GORINI  John D. C. LINNELL  Luigi BOITANI  Ulrike HAUPTMANN  Morten ODDEN  Per WEGGE  Erlend B. NILSEN 《Integrative zoology》2011,6(4):299-310

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Bacteria subsisting on antibiotics     

Dantas G  Sommer MO  Oluwasegun RD  Church GM 《Science (New York, N.Y.)》2008,320(5872):100-103

Antibiotics are a crucial line of defense against bacterial infections. Nevertheless, several antibiotics are natural products of microorganisms that have as yet poorly appreciated ecological roles in the wider environment. We isolated hundreds of soil bacteria with the capacity to grow on antibiotics as a sole carbon source. Of 18 antibiotics tested, representing eight major classes of natural and synthetic origin, 13 to 17 supported the growth of clonal bacteria from each of 11 diverse soils. Bacteria subsisting on antibiotics are surprisingly phylogenetically diverse, and many are closely related to human pathogens. Furthermore, each antibiotic-consuming isolate was resistant to multiple antibiotics at clinically relevant concentrations. This phenomenon suggests that this unappreciated reservoir of antibiotic-resistance determinants can contribute to the increasing levels of multiple antibiotic resistance in pathogenic bacteria.  相似文献   

Relationship between the metabolite profile and technological properties of bovine milk from two dairy breeds elucidated by NMR-based metabolomics     

Sundekilde UK  Frederiksen PD  Clausen MR  Larsen LB  Bertram HC 《Journal of agricultural and food chemistry》2011,59(13):7360-7367

The aim of the present study was to investigate the relationship between the metabolite profile of milk and important technological properties by using nuclear magnetic resonance (NMR)-based metabolomics. The metabolomics approach was introduced for the metabolic profiling of a set of milk samples from two dairy breeds representing a wide span in coagulation properties. The milk metabolite profiles obtained by proton and carbon NMR spectroscopy could be correlated to breed and, more interestingly, also with the coagulation profile, as established by traditional methods by using principal component analysis (PCA). The metabolites responsible for the separation into breed could mainly be ascribed to carnitine and lactose, whereas the metabolites varying in the samples with respect to coagulation properties included citrate, choline, carnitine, and lactose. The results found in the present study demonstrated a promising potential of NMR-based metabolomics for a rapid analysis and classification of milk samples, both of which are useful for the dairy industry.  相似文献   

Mineralization of the herbicide MCPA in urban soils is linked to presence and growth of class III tfdA genes     

Morten S. Nielsen 《Soil biology & biochemistry》2011,43(5):984-990

Mineralization and sorption of ¹⁴C-ring labeled herbicide 2-methyl-4-chlorophenoxyacetic acid (MCPA) were quantified along with the tfdA gene abundance in 7 different soils. The soils tested were five gravel soils from urban locations, one soil from the embankment of a railway track, and finally an agricultural soil as a control. The mineralization experiments were performed with a concentration of MCPA of 5 mg/kg and incubated at 10 °C for a period of 60 days.With K_d values ranging from 0.04 to 0.41 l kg⁻¹ the sorption experiments revealed that binding of MCPA to the six gravel soils was lower compared to the control soil which had a K_d value of 0.91 l kg⁻¹. The potential for MCPA mineralization varied from less than 5 to over 55% mineralized in 60 days. The most rapid MCPA mineralization was observed in the soil from the Danish railway tracks with 55% mineralized after only 18 days. The mineralization data was fitted to degradation kinetic models, which indicated that growth occurred as a response to MCPA degradation in most of the soils.Soil DNA was extracted and tfdA genes responsible for the first step in MCPA degradation were quantified by real-time PCR (qPCR) at appropriate time points throughout the mineralization experiments. Indicating growth of specific MCPA degraders, the abundance of class III tfdA genes showed an increase during MCPA mineralization in those soils able to mineralize MCPA.These findings emphasize the importance of the presence of microorganisms that are able to readily degrade MCPA, to avoid groundwater leaching following use on urban gravel areas that possess low binding ability of the compound.  相似文献   

OCCURRENCE OF AVIDIN IN THE OVIDUCT AND SECRETIONS OF THE GENITAL TRACT OF SEVERAL SPECIES     

Hertz R  Sebrell WH 《Science (New York, N.Y.)》1942,96(2489):257-258

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