Thyroid Dysplasia in Wistar Hannover GALAS Rats     

Weber K  Ernst R  Fankhauser H  Hardisty JF  Heider W  Stevens K 《Journal of toxicologic pathology》2009,22(4):247-254

Thyroid dysplasia was recognized in WistarHan GALAS rats and confirmed as a heritable congenital disorder. The gene or genes involved were not identified, but homozygous animals with thyroid dysplasia also exhibited stunted growth, had reduced pituitary gland growth hormone (GH) and were hypothyroid. Heterozygous animals exhibited thyroid dysplasia with normal thyroid hormonal homeostasis and no difference in the incidence of preneoplastic or neoplastic lesions in oncogenicity studies.  相似文献   

Editorial J. Plant Nutr. Soil Sci. 1/2010     

Karl‐Heinz Feger  Sven Schubert 《植物养料与土壤学杂志》2010,173(1):3-3

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Microarray analysis of Haemophilus parasuis gene expression under in vitro growth conditions mimicking the in vivo environment     

Melnikow E  Dornan S  Sargent C  Duszenko M  Evans G  Gunkel N  Selzer PM  Ullrich HJ 《Veterinary microbiology》2005,110(3-4):255-263

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Connectivity in Heterogeneous Landscapes: Analyzing the Effect of Topography     

Guy Pe’er  Simone K. Heinz  Karin Frank 《Landscape Ecology》2006,21(1):47-61

Animal response to landscape heterogeneity directs dispersal and affects connectivity between populations. Topographical heterogeneity is a major source of landscape heterogeneity, which is rarely studied in the contexts of movement, dispersal, or connectivity. The current study aims at characterizing and quantifying the impacts of topography on landscape connectivity. We focus on ‘hilltopping’ behavior in butterflies, a dispersal-like behavior where males and virgin females ascend to mountain summits and mate there. Our approach integrates three elements: an individual-based model for simulating animal movements across topographically heterogeneous landscapes; a formula for the accessibility of patches in homogenous landscapes; and a graphical analysis of the plots of the simulation-based vs. the formula-based accessibility values. We characterize the functional relationship between accessibility values and landscape structure (referred to as ‘accessibility patterns’) and analyze the influence of two factors: the intensity of the individuals’ response to topography, and the level of topographical noise. We show that, despite the diversity of topographical landscapes, animal response to topography results in the formation of two, quantifiable accessibility patterns. We term them ‘effectively homogeneous’ and ‘effectively channeled’. The latter, in which individuals move toward a single summit, prevails over a wide range of behavioral and spatial parameters. Therefore, ‘channeled’ accessibilities may occur in a variety of landscapes and contexts. Our work provides novel tools for understanding and predicting accessibility patterns in heterogeneous landscapes. These tools are essential for linking movement behavior, movement patterns and connectivity. We also present new insights into the practical value of ecologically scaled landscape indices.  相似文献   

Is Change in Electrical Potential or pH a Hatching Signal for Heterodera glycines?     

Pike SM  Heinz R  Walk T  Jones C  Kraus GA  Gassmann W  Novacky AJ  Niblack TL 《Phytopathology》2002,92(5):456-463

ABSTRACT This study explored the possibilities that changes in the egg shell/lipid layer electrical potential or pH communicate external hatching conditions to the Heterodera glycines second-stage juvenile (J2) within the mature egg and that electrophysiology could measure effects of chemicals on emergence. Potentials were measured following application of the emergence inducers (ZnSO(4) and ZnCl(2)), ions that do not affect emergence, or synthetic emergence inhibitors. Results were compared with pH measurements and emergence bioassays. Healthy appearing eggs had negative resting potentials. Application of ZnSO(4) caused a smooth depolarization. However, eggs containing J2 and immature eggs depolarized to a similar degree when ZnSO(4) was added. In addition, ZnSO(4), synthetic emergence inhibitors, and CaCl(2) caused similar depolarization, and some depolarization was measured in dye-permeable eggs and empty shells. Results suggest that change in cation surface charge contributed to depolarization and that Cl penetrated the egg shell/lipid layer without causing potential changes. In bioassays, zinc consistently stimulated emergence to a greater degree than H(2)O, other cations, or buffers, and counteracted emergence inhibitors. Zinc-caused emergence stimulation was independent of pH. In summary, it is concluded that depolarization and pH are not emergence signals and electrophysiology is unlikely to measure effectiveness of emergence stimulators or inhibitors.  相似文献   

Consequences of N Deposition to Forest Ecosystems - Recent Results and Future Research Needs     

Heinz Rennenberg  Arthur Gessler 《Water, air, and soil pollution》1999,116(1-2):47-64

Wet and dry deposition of atmospheric nitrogen (N) compounds into forest ecosystems and their effect on physical, chemical and microbial processes in the soil has attracted considerable attention for many years. Still the consequences of atmospheric N deposition on N metabolism of trees and its interaction with soil microbial processes has only recently been studied. Atmospheric N deposited to the leaves is thought to enter the general N metabolism of the leaves, but the processes involved, the interaction with different metabolic pathways, and the connection between injury by atmospheric N and its metabolic conversion are largely unknown. Laboratory and field experiments have shown that N of atmospheric NO₂ and NH₃, deposited to the leaves of trees, is subject to long-distance transport in the phloem to the roots. This allocation can result in considerable decline of N uptake by the roots. Apparently, the flux of N from the soil into the roots can be down-regulated to an extent that equals N influx into the leaves. This down-regulation is not mediated by generally enhanced amino-N contents, but by elevated levels of particular amino acids. Field experiments confirm these results from laboratory studies: Nitrate (NO₃) uptake by the roots of trees at a field sites exposed to high loads of atmospheric N is negligible, provided concentrations of Gln in the roots are high. At the ecosystem level, consequences of reduced N uptake by the roots of trees exposed to high loads of atmospheric N are (1) an increased availability of N for soil microbial processes, (2) enhanced emission of gaseous N-oxides from the soil, and (3) elevated leaching of NO₃ into the ground water. How recent forest management practices aimed at transforming uniform monocultures to more structured species-rich forests will interact with these processes remains to be seen. Possible implications of these forest management practices on N metabolism in trees and N conversion in the soil are discussed particularly in relation to atmospheric N deposition.  相似文献   

Reliming and reacidification effects on lakewater     

W. Dickson  H. Borg  C. Ekström  E. Hörnström  T. Grönlund 《Water, air, and soil pollution》1995,85(2):919-924

Long term liming and reacidification effects were studied in SW Sweden. This report is a concentrated summary. Lake liming reduces toxic levels of Al, Cd and Zn so that pH-sensitive species can survive. But it mobilizes nutrients and causes internal eutrophication, which in shallow lakes may give problems as macrophyte expansion. Reacidification kills much of the flora and fauna, that adapted during limed conditions. The reasons are lowered pH and toxic levels: Al 500 ug/1, Cd 0.4 ug/1 and Zn 50 ug/1. Sediments are fragile and temporary refuges for metals and nutrients. Conclusively, surface waters should be limed before they reach lakes.  相似文献   

Monitoring of effects induced by recombinant equine interferon-beta 1 in whole blood and separated fractions of peripheral blood of horses.     

J Marquardt  J Heymer  H Heinz  E Deegen  G R Adolf  W Leibold 《Zentralblatt für Veterin?rmedizin. Reihe B. Journal of veterinary medicine. Series B》1992,39(5):327-336

Interferon is known to induce antiviral mechanisms and to exert immunoregulatory capacities on various cell types. The antiviral capacity of recombinant equine interferon-beta 1 (rEqIFN-beta 1) is most sensitively monitored by indirect quantitation of multiplication of vesicular stomatitis virus (VSV) in blood cells of horses. As few as 0.5 pg rEqIFN-beta 1/ml can be assessed by means of 90% reduction of VSV-replication in whole blood (w.b.) as well as in isolated mononuclear blood cells (MNC) in spite of individual variations. The immunoregulatory influence of 20-50 pg rEqIFN-beta 1/ml is sufficient to cause at least a 50% reduction of mitogen-induced lymphocyte proliferation in MNC, while higher concentrations are needed in w.b. Of the mitogens tested the best stimulation of proliferation on the equine lymphoid cells was obtained with staphylococcal enterotoxin B (SEB). Release of reactive oxygen species (ROS) from phagocytic cells in w.b. or from isolated polymorphonuclear cells (PMN) as monitored by chemiluminescence (CL) does not seem suitable for evaluation of rEqIFN-beta 1-induced immunoregulation as only very high rEqIFN-beta 1-concentrations (10(3)-10(4) pg/ml) result in a minute increase (up to 20%) of CL. Comparative studies on w.b. and isolated leukocyte fractions from identical specimens of individual horses suggest that monitoring of antiviral and distinct immunoregulatory capacities of rEqIFN-beta 1 can be performed on w.b. without loss of information and sensitivity as compared to isolated MNC.  相似文献   

Genetic evidence for multi-event imports of avian influenza virus A (H5N1) into Bavaria, Germany.     

Monika Rinder  Victoria Lang  Cordula Fuchs  Angela Hafner-Marx  Karl-Heinz Bogner  Antonie Neubauer  Mathias Büttner  Heinz Rinder 《Journal of veterinary diagnostic investigation》2007,19(3):279-282

The almost simultaneous initial detections of avian influenza A H5N1 viruses in central Europe in February 2006, at a time devoid of migratory bird activity, raised the question of the origin of these viruses. This report presents molecular data from Europe providing evidence for multiple and spatially overlapping H5N1 introductions into Bavaria, Germany.  相似文献   

Vegetationskundliche Untersuchungen an Fichtenforsten im Mittleren Thüringer Wald     

Heinz Schlüter 《Genetic Resources and Crop Evolution》1965,13(1):53-99

Zusammenfassung 1. Nach einer kurzen Einführung in das Untersuchungsgebiet Mittlerer Thüringer Wald und seine natürliche Vegetationsgliederung werden einige theoretische Fragen diskutiert: Forstgesellschaften können nur mit Hilfe von Trennarten gegeneinander abgegrenzt werden. Wegen des Fehlens von Charakterarten handelt es sich bei ihnen nicht um Assoziationen im Sinne der Schule Zürich-Montpellier. Darum lassen sie sich auch nicht in das Vegetationssystem einfügen, und es empfiehlt sich auch nicht, sie wissenschaftlich zu benennen.2. Die durch Tabellenvergleich herausgearbeiteten Trennarten der Fichtenforste des Untersuchungsgebietes werden zu 12 Ökologisch-soziologischen Gruppen zusammengefaßt. Sie erlauben die Bestimmung der Fichten-Forstgesellschaften und ihrer Untereinheiten sowie die Einschätzung der Standortsverhältnisse.3. Die Fichten-Forstgesellschaften sind im Thüringer Wald von den natürlichen Fichtenwäldern soziologisch und räumlich gut abzugrenzen. Ihre unmittelbare Ableitung von natürlichen Waldgesellschaften ist nur in seltenen Ausnahmefällen möglich. Die festgestellte Zweiteilung in bessere, krautreiche Sauerklee-Fichtenforste und arme Klauenmoos-Fichtenforste ist auch für andere Mittelgebirge charakteristisch.4. Es werden 6 Fichten-Forstgesellschaften nebst Untereinheiten beschrieben und in Tabellen dargestellt. Zu den Standortsverhältnissen bestehen deutliche Beziehungen. Die Sauerklee-Fichtenforste sind auf bessere Ausgangsgesteine beschränkt, während die Klauenmoos-Fichtenforste in der Hauptsache arme Standorte besiedeln. Von wesentlicher Bedeutung ist der Wasserhaushalt; einige Einheiten sind streng expositionsgebunden.5. Eine sekundäre Sukzession führt im Zuge der Bestandesentwicklung zu einer allmählichen Vervollständigung der Artengarnitur. In Hochlagen und an steilen Süd- bis Westhängen entwickeln sich im Altholz vielfach Drahtschmielen-Stadien, die je nach ihrer Herkunft unterschiedlich zu beurteilen sind. Nach Bestandeskalkung setzt eine rückläufige Entwicklung in Richtung auf die natürliche Ausgangsgesellschaft ein, indem ± nitrophile Fagetalia-und Querco-Fagetea-Arten erscheinen.6. Eine relativ geringe Abwandlung durch den Fichten-Reinanbau erfährt die Waldbodenflora an guten Hangstandorten reicher Laubwälder, an bodenwasserbeeinflußten Standorten oder bei azidophilen Ausgangsgesellschaften mit einem höheren ursprünglichen Nadelholzanteil. Eine Abhängigkeit der Fichten-Forstgesellschaften von der Dauer reiner Fichtenbestockung konnte nicht nachgewiesen werden.7. Orientierende ertragskundliche Untersuchungen ergaben deutliche Beziehungen zwischen Fichten-Forstgesellschaft und Höhenzuwachs. Es liegen der Farn-Sauerklee-Fichtenforst bei Ertragsklasse I, typische Sauerklee-Fichtenforste bei I/II, Klauenmoos-Fichtenforste um III, ihre Weißmoos-Varianten zwischen IV und V.

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Summary Spruce monocultures were studied plant sociologically in the Thuringian mountain forest region outside the area of natural spruce forests. Different spruce forest communities can be distinguished by selected groups of plant species, which are also rated for their ecological significantion. These communities cannot be regarded as associations as there are no characterising species in it. Therefore, they do not fit with the existing vegetation system.We find there stands withOxalis acetosella and some other kinds of plants of rank soil and others of poor acid soil with mosses as dominating plants. Water-balance is also of importance and for some communities the exposition or the height. It could be shown that there are clear relations between the abovementioned communities and the growth-rate of the spruce in them.

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