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31.
Dissolved and colloidal phosphorus fluxes in forest ecosystems—an almost blind spot in ecosystem research
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Roland Bol Dorit Julich Dominik Brödlin Jan Siemens Klaus Kaiser Michaela Anna Dippold Sandra Spielvogel Thomas Zilla Daniela Mewes Friedhelm von Blanckenburg Heike Puhlmann Stefan Holzmann Markus Weiler Wulf Amelung Friederike Lang Yakov Kuzyakov Karl‐Heinz Feger Nina Gottselig Erwin Klumpp Anna Missong Carola Winkelmann David Uhlig Jakob Sohrt Klaus von Wilpert Bei Wu Frank Hagedorn 《植物养料与土壤学杂志》2016,179(4):425-438
Understanding and quantification of phosphorus (P) fluxes are key requirements for predictions of future forest ecosystems changes as well as for transferring lessons learned from natural ecosystems to croplands and plantations. This review summarizes and evaluates the recent knowledge on mechanisms, magnitude, and relevance by which dissolved and colloidal inorganic and organic P forms can be translocated within or exported from forest ecosystems. Attention is paid to hydrological pathways of P losses at the soil profile and landscape scales, and the subsequent influence of P on aquatic ecosystems. New (unpublished) data from the German Priority Program 1685 “Ecosystem Nutrition: Forest Strategies for limited Phosphorus Resources” were added to provide up‐to‐date flux‐based information. Nitrogen (N) additions increase the release of water‐transportable P forms. Most P found in percolates and pore waters belongs to the so‐called dissolved organic P (DOP) fractions, rich in orthophosphate‐monoesters and also containing some orthophosphate‐diesters. Total solution P concentrations range from ca. 1 to 400 µg P L?1, with large variations among forest stands. Recent sophisticated analyses revealed that large portions of the DOP in forest stream water can comprise natural nanoparticles and fine colloids which under extreme conditions may account for 40–100% of the P losses. Their translocation within preferential flow passes may be rapid, mediated by storm events. The potential total P loss through leaching into subsoils and with streams was found to be less than 50 mg P m?2 a?1, suggesting effects on ecosystems at centennial to millennium scale. All current data are based on selected snapshots only. Quantitative measurements of P fluxes in temperate forest systems are nearly absent in the literature, probably due to main research focus on the C and N cycles. Therefore, we lack complete ecosystem‐based assessments of dissolved and colloidal P fluxes within and from temperate forest systems. 相似文献
32.
ABSTRACT: Classical swine fever virus (CSFV) C-strain "Riems" escape variants generated under selective antibody pressure with monoclonal antibodies and a peptide-specific antiserum in cell culture were investigated. Candidates with up to three amino acid exchanges in the immunodominant and highly conserved linear TAV-epitope of the E2-glycoprotein, and additional mutations in the envelope proteins ERNS and E1, were characterized both in vitro and in vivo.It was further demonstrated, that intramuscular immunization of weaner pigs with variants selected after a series of passages elicited full protection against lethal CSFV challenge infection. These novel CSFV C-strain variants with exchanges in the TAV-epitope present potential marker vaccine candidates. The DIVA (differentiating infected from vaccinated animals) principle was tested for those variants using commercially available E2 antibody detection ELISA. Moreover, direct virus differentiation is possible using a real-time RT-PCR system specific for the new C-strain virus escape variants or using differential immunofluorescence staining. 相似文献
33.
Schmidburg I Pagger H Zsoldos RR Mehnen J Peham C Licka TF 《Veterinary journal (London, England : 1997)》2012,192(3):525-528
Laterolateral radiographs of equine necks are reported to be inaccurate in determining the site of spinal cord lesions even when a myelogram is carried out. The goal of this study was to assess constrictions present in the cervical vertebral canal at any time point throughout the extremes of movement. Sixteen equine cervical vertebral columns without history of cervical disease were used. After removal of the spinal cord, the dura mater was filled with polyurethane foam and during its plastic phase the cervical vertebral column was passively moved in flexion-extension, lateral bending and 30° rotated flexion and extension. Resulting moulded foam structures were scanned with a 3D laser scanner. Functional narrowing of the vertebral canal was located in the dorsolateral or ventrolateral regions, explaining its under-representation on laterolateral radiographs. 相似文献
34.
Aupperle H Thielebein J Kiefer B März I Dinges G Schoon HA 《Veterinary journal (London, England : 1997)》2009,180(1):88-94
While the pathogenesis of chronic valvular disease (CVD) in dogs remains unclear, alterations in the activity of specific metalloproteinase enzymes and their inhibitors within the valve stroma are suspected of having a role. This study describes the immunohistochemical distribution pattern of matrix metalloproteinase (MMP) types 2, 9 and 14 and their tissue inhibitors, termed tissue inhibitors of metalloproteinase (TIMP), types 2 and 3, in normal canine mitral valves (MVs) (n=10) and in dogs with mild (n=7), moderate (n=14) and severe (n=9) CVD. In normal MVs, MMP-2 and -14, and TIMP-2 were expressed in isolated stromal cells. Tissue inhibitor of metalloproteinase-3 exhibited moderate intracellular and mild extracellular expression. With increasing severity of CVD, the expression of MMP-2 decreased. The number of stromal cells expressing MMP-14 increased, predominantly in the margins of the nodular lesions. Tissue inhibitor of metalloproteinase-2 and -3 expression increased both intra- and extracellularly. Matrix metalloproteinase-9 was not detected in normal or diseased valves. In conclusion, CVD was characterised by alterations in the distribution and intensity of valvular MMP and TIMP expression, suggesting that depressed catabolism and the accumulation of extracellular matrix components within affected valves contributes to their structural alteration and consequent loss of function. 相似文献
35.
Jonathan P. BrayMVSc CERTSAS MACVSc MRCVS Vicky J. LipscombeBA VETMB MRCVS Richard A.S. WhiteBVETMED PHD DSAS DVR FRCVS Heike RudorfDR.MED.VET. DVR MRCVS 《Veterinary radiology & ultrasound》1998,39(6):566-571
Real-time ultrasonographic examination of the canine larynx was performed in 12 normal dogs using a 7.5-mHz mechanical sector scanner combined with a stand-off. A variety of breeds and ages were examined. All examinations were performed in nonsedated, conscious animals. Transverse scans were found to provide the most reliable and interpretable images. Identification of laryngeal structures included the epiglottis, laryngeal and cricoid cartilages, and the vocal cords. In conscious animals, abduction and adduction of the vocal cords associated with respiration could be identified if the animal was made to pant during the examination. Movement of the vocal cords could also be quantified by pulse-wave Doppler recording. In all animals, recordings were made during inspiration only, with muscular vibration at a rate less than 0.1 m/s. 相似文献
36.
Eva Syrová Miroslava Palíková Jan Mendel Veronika Seidlová Ivana Papežíková Heike Schmidt-Posthaus Kristina Somerlíková Hana Minářová Lukáš Mareš Ivana Mikulíková Jiří Pikula Jan Mareš 《Journal of fish diseases》2020,43(10):1201-1211
Tetracapsuloides bryosalmonae (Myxozoa: Malacosporea) is the causative agent of proliferative kidney disease (PKD), which affects both wild and farmed salmonid fish. The objective of this study was to outline differences in susceptibility to PKD in different salmonid species, hybrids and breeding lineages. Susceptibility to T. bryosalmonae infection was established based on cumulative mortality, pathological findings and detection of T. bryosalmonae in the kidney using immunohistochemistry and molecular methods. Determination of pure and hybrid individuals of different species in the genus Salvelinus, and dissimilarity of rainbow trout lineages, was performed using traditional polymerase chain reaction (PCR) and microsatellite analyses. Rainbow trout displayed higher disease severity compared with brook trout and Alsatian charr. Moreover, the results indicated differences in infection susceptibility, not only among different salmonid species but also among different lineages of charr and rainbow trout. Our study indicated that some salmonid species and even different lineages of the same species are more suitable for farming under PKD pressure. 相似文献
37.
Heike Kawaletz Inga Mölder Peter Annighöfer André Terwei Stefan Zerbe Christian Ammer 《Annals of Forest Science》2014,71(3):337-347
Context
Identifying the traits of exotic species may explain their invasiveness and help control the negative impacts of these species on native ecosystems. In this study, we investigated root competition as an important driver for the competitiveness of two exotic tree species in the seedling stage.Aims
In a pot experiment, carried out in Central Europe, we studied the effect of root competition of two exotic tree species (Prunus serotina Ehrh. and Robinia pseudoacacia L.) on biomass allocation of two native ones (Quercus robur L. and Carpinus betulus L.).Methods
Seedlings of these species were exposed to intra- and interspecific mixtures with and without the effect of root competition. For this, belowground plastic partitions were installed in the pots.Results
Competition intensity in the pots increased over time, irrespective of mixture type. However, this increase was much higher for the native species if mixed with the exotic species compared to monocultures or inter-native mixtures. In addition to ontogeny, competition affected biomass allocation patterns. Under root competition by the exotic species, the native species preferentially allocated their biomass to the roots. A higher allocation to the roots was mainly achieved at the expense of leaf and branch biomass.Conclusion
Root competition of P. serotina and R. pseudoacacia may be a reason for the lack of Q. robur and C. betulus in the seedling stage in natural environments where all four species occur. 相似文献38.
Kiers ET Duhamel M Beesetty Y Mensah JA Franken O Verbruggen E Fellbaum CR Kowalchuk GA Hart MM Bago A Palmer TM West SA Vandenkoornhuyse P Jansa J Bücking H 《Science (New York, N.Y.)》2011,333(6044):880-882
Plants and their arbuscular mycorrhizal fungal symbionts interact in complex underground networks involving multiple partners. This increases the potential for exploitation and defection by individuals, raising the question of how partners maintain a fair, two-way transfer of resources. We manipulated cooperation in plants and fungal partners to show that plants can detect, discriminate, and reward the best fungal partners with more carbohydrates. In turn, their fungal partners enforce cooperation by increasing nutrient transfer only to those roots providing more carbohydrates. On the basis of these observations we conclude that, unlike many other mutualisms, the symbiont cannot be "enslaved." Rather, the mutualism is evolutionarily stable because control is bidirectional, and partners offering the best rate of exchange are rewarded. 相似文献
39.
Marsicano G Goodenough S Monory K Hermann H Eder M Cannich A Azad SC Cascio MG Gutiérrez SO van der Stelt M López-Rodriguez ML Casanova E Schütz G Zieglgänsberger W Di Marzo V Behl C Lutz B 《Science (New York, N.Y.)》2003,302(5642):84-88
Abnormally high spiking activity can damage neurons. Signaling systems to protect neurons from the consequences of abnormal discharge activity have been postulated. We generated conditional mutant mice that lack expression of the cannabinoid receptor type 1 in principal forebrain neurons but not in adjacent inhibitory interneurons. In mutant mice,the excitotoxin kainic acid (KA) induced excessive seizures in vivo. The threshold to KA-induced neuronal excitation in vitro was severely reduced in hippocampal pyramidal neurons of mutants. KA administration rapidly raised hippocampal levels of anandamide and induced protective mechanisms in wild-type principal hippocampal neurons. These protective mechanisms could not be triggered in mutant mice. The endogenous cannabinoid system thus provides on-demand protection against acute excitotoxicity in central nervous system neurons. 相似文献
40.
Heike Bohne 《植物养料与土壤学杂志》1991,154(3):199-203
The utilization of water and Ca and K from compacted non-rooted areas between macropores for two soils with different texture In pot experiments with wheat-seedlings and aggregates from a silty Luvisol and a clayic stagni-gleyic Cambisol it was investigated how water, Ca and K are utilized from the dense non-rooted soil between vertical rooted macropores (6, 3, 2 per volume). Root and shoot growth as well as water extraction was increased and the transpiration coefficient decreased for the plants grown in the pot with 3 macropores. During the early stage of growth most Ca was extracted from the pot with short flow distances. The utilization of K in this stage of growth was improved by long flow distances. For the stagni-gleyic Cambisol most dry matter of shoots and roots was produced and most water was extracted from the pot with short flow distances. The transpiration coefficient was smallest in this pot as well. 相似文献