Aboveground vegetation effects on the deposition and cycling of atmospheric sulfur: Chemical and stable isotope evidence     

D. R. van Stempvoort  J. J. Wills  P. Fritz 《Water, air, and soil pollution》1991,60(1-2):55-82

Up to 60% of the sulfate in upland forest throughfall and stemflow at Plastic Lake in central Ontario is non-precipitation by origin, but is derived from aboveground vegetation. The sources of this aboveground vegetation sulfate include dry deposited aerosols and SO₂, and mineralized plant organic S. σ³⁴S data indicate that atmospheric S dominates the upland forest ecosystems of southern and central Ontario, with little S isotope fractionation. Seasonal σ³⁴S variations in precipitation sulfate may be due to mixing of bacteriogenic and anthropogenic S. σ¹⁸O and concentration data indicate that oxidation of dry-deposited SO₂, and mineralization of organic S on vegetation surfaces may contribute one third or more of throughfall sulfate in summer and autumn, but less in late spring, perhaps due to foliar uptake of S during this season. Oxidized SO₂, or mineralized organic S contributes one third or more of stemflow sulfate during these seasons.  相似文献   

A follow up study on antibodies against Lawsonia intracellularis in mares and foals from two breeding farms in Germany     

Breuer J  Schmoll F  Uhlig A  Schusser GF 《Berliner und Münchener tier?rztliche Wochenschrift》2011,124(7-8):337-342

Equine proliferative enteropathy (EPE) caused by Lawsonia (L.) intracellularis is an emerging disease in foals, particularly in North America. Since a case report in Germany exists, the objective of this study was to examine the incidence of L. intracellularis-antibodies in healthy horses from two German breeding farms. In group 1, serum samples from 24 (year 1) and 16 (year 2) Haflinger mares and their foals were taken. In group 2, over a period of five months, serum samples of six warmblood mares and foals were collected monthly from birth until the foals became seronegative. Serum samples were tested using an ELISA system. Results are expressed as Percentage of Inhibiton (PI). All adult mares (100%) of both groups were seropositive at each point in time (PI-value > 30). In group 1,7/24 foals (29.2%) in year 1 and 4/16 foals (25%) in year 2 had antibodies.The seropositive foals from year 2 had the same dams as the seropositive foals from year 1. In group 2 five of six foals were seropositive after birth. Antibodies decreased from March to July in mares and foals. In July, all five foals tested negative for the first time between the ages of 82 and 141 days (median 115 days). PI-values of mares were significantly correlated with PI-values of their foals. Higher PI-values were seen in younger foals and early in spring. Loss of antibodies in foals at the age of three to five months could be a risk factor for infection and appearance of EPE.  相似文献   

Differentiation of viable, apoptotic and necrotic cells in bronchoalveolar lavage fluid of normal horses and horses with recurrent airway obstruction     

Breuer J  Müller U  Locher L  Spallek A  Recknagel S  Uhlig A  Schusser GF 《Berliner und Münchener tier?rztliche Wochenschrift》2011,124(3-4):154-160

Proinflammatoric cytokines are released extracellularly during necrosis. These lead to inflammation and destruction of surrounding tissues. The aim of this study was to compare the number of viable, apoptotic and necrotic cells in the bronchoalveolar lavage fluid (BALF) of normal horses and horses with recurrent airway obstruction (RAO) and to determine if fluorescence microscopy is a reliable method for this examination. A group of six normal horses and a group of ten horses with RAO were examined. Samples were assessed using annexin-V and propidium iodide immunofluorescence assay and examined by fluorescence microscopy (16 horses) and flow cytometry (nine of 16 horses). We found no significant differences in percentages of apoptotic and viable cells between both groups. The number of necrotic cells was significantly increased in horses with RAO counted by fluorescence microscopy. Cells with high granularity and macrophages had a significantly higher percentage of necrotic cells than lymphocytes. There was a good agreement between both methods. No significant differences were detected. The correlation between both methods is significant. Higher amounts of necrotic cells in the bronchial lumina of horses with RAO could be a reason for tissue damage and continuous lung tissue inflammation. Fluorescence microscopy was applicable for examination of BALF. Therapy should be aimed at the reduction of necrotic cells in the bronchial lumina. Further studies are required to find ways to reduce inflammatory cell infiltration and necrosis in bronchial lumina.  相似文献   

Acute monocytic leukemia in an irradiated Beagle.     

D V Tolle  T M Seed  T E Fritz  L S Lombard  C M Poole  W P Norris 《Veterinary pathology》1979,16(2):243-254

A purebred female Beagle dog that had received 2,000 R of protracted wholebody gamma-irradiation from 60Co when 14 months old had hematologic changes consistent with a myeloproliferative disorder 3 years after the termination of radiation exposure. Peripheral blood and bone marrow findings during the 7-month period before death showed progressive anemia with increased numbers of platelets; immature granulocytes, monocytes and promonocytes. A period of partial remission occurred during which time the peripheral blood was aleukemic, although there was marked thrombocytosis and abnormal erythropoiesis which was evidenced by bizarre circulating nucleated red cells, anisocytosis, poikilocytosis and Howell-Jolly bodies. The dog had a terminal crisis with marked leukocytosis, most cells in the peripheral blood being bizarre monocytes and promonocytes. Tissues obtained at necropsy showed diffuse as well as focal infiltration of the spleen, liver, lymph nodes, heart, kidney and gastrointestinal wall with immature neoplastic cells resembling monocytes and monocytic precursors. The monocytic differentiation of the invasive cell population was confirmed by morphological, cytochemical, histological, ultrastructural and in vitro cell culture studies.  相似文献   

The configuration of the Cu(2+) binding region in full-length human prion protein compared with the isolated octapeptide     

Weiss A  Del Pino P  Bertsch U  Renner C  Mentler M  Grantner K  Moroder L  Kretzschmar HA  Parak FG 《Veterinary microbiology》2007,123(4):358-366

The cellular prion protein (PrP(C)) is a copper binding protein. The molecular features of the Cu(2+) binding sites have been investigated and characterized by spectroscopic experiments on PrP(C)-derived peptides and the correctly folded human full-length PrP(C) (hPrP-[23-231]). These experiments allowed us to distinguish two different configurations of copper binding. The different copper complexes depend on sequence context, buffer conditions and stoichiometry of copper. The combined information of spectroscopic data from our EXAFS, EPR and ENDOR experiments was used to create models for these two copper complexes. A large number of conformations of these models were calculated using molecular mechanics computations, and the simulated spectra of these structures were compared with our experimental data. Common features and differences of the copper binding motifs are discussed in this paper and it remains for future investigations to study whether different configurations are associated with different functional states of PrP(C).  相似文献   

Kinetics of microbial phosphorus uptake in cultivated soils   总被引：5，自引：0，他引：5  

Fritz Oehl  Astrid Oberson  Mirjam Probst  Andreas Fliessbach  Hans-Rudolf Roth  Emmanuel Frossard 《Biology and Fertility of Soils》2001,34(1):31-41

Knowledge about the role of microorganisms in P cycling at conditions of constant soil respiration rates and constant size of microbially bound P is lacking. To study the kinetics of microbial P uptake and cycling under such conditions, soils differing in biological activity were ³³PO₄ labelled by introducing a carrier-free tracer solution and incubated for 56 days. The ³³PO₄ incorporation into the fraction of microbial P releasable by chloroform treatment (P_chl) was assessed and the isotopic composition [=specific activity (SA); SA=³³PO₄/³¹PO₄] of P_chl and soil solution P compared. Soils were taken from a 20-year-old field experiment including a non-fertilised control (NON), a minerally fertilised conventional (MIN) and two organic farming systems [bio-organic (ORG); bio-dynamic (DYN)]. Tracer P incorporation continuously increased during incubation in DYN, ORG and MIN soils. It decreased in the order DYN>ORG>MIN, with differences in ³³PO₄ uptake between the farming systems being higher than suggested by the differences in the amount of P_chl. In the P-deficient NON soil, the highest initial incorporation of tracer P was found, but no additional uptake could be detected thereafter. In all soils, the SA of P_chl converged to the SA of the soil solution with increasing time. Since P_chl remained almost constant during the experiment, the findings suggest an intensive uptake of P from the soil solution into P_chl and concomitant release of P back to the soil solution and, thus, a rapid cycling through P_chl. Intensive P cycling between P_chl and the soil solution was confirmed in an additional experiment where microbial activity was stimulated by glucose and N additions.  相似文献   

Effects of Negative Pressure Wound Therapy on Healing of Free Full‐Thickness Skin Grafts in Dogs     

Bryden J. Stanley BVMS  MVetSc  Diplomate ACVS  Kathryn A. Pitt DVM  Christian D. Weder BS  Michele C. Fritz BS  LVT  Joe G. Hauptman DVM  MS  Diplomate ACVS  Barbara A. Steficek DVM  PhD  Diplomate ACVP 《Veterinary surgery : VS》2013,42(5):511-522

  相似文献   

Genotypes and phenotypes of an <Emphasis Type="Italic">ex situ</Emphasis><Emphasis Type="Italic">Vitis vinifera</Emphasis> ssp. <Emphasis Type="Italic">sylvestris</Emphasis> (Gmel.) Beger germplasm collection from the Upper Rhine Valley     

Susanne Barth  Astrid Forneck  Fabienne Verzeletti  Rolf Blaich  Fritz Schumann 《Genetic Resources and Crop Evolution》2009,56(8):1171-1181

  相似文献   

Parasitoids Associated with <Emphasis Type="Italic">Mussidia</Emphasis> spp. (Lepidoptera: Pyralidae) in Kenya     

Benjamin Kimwele Muli  Fritz Schulthess  Johnnie van den Berg 《Phytoparasitica》2009,37(1):55-60

The pyralid Mussidia nigrivenella, a pest of cotton, maize and Phaseolus bean in West Africa, has never been reported as a crop pest in East and Southern Africa, although reportedly it exists in the wild. It is hypothesized that the difference in pest status of M. nigrivenella between western and eastern Africa was either due to differences in natural enemy compositions or that there exist several populations and/or species of Mussidia, which vary in their host plant range. Thus, a catalogue of parasitoids of Mussidia spp. was established through surveys in mid-altitude and coastal Kenya, between 2006 and 2007. Mussidia spp. eggs, larvae and pupae were collected from fruits of plants known to host Mussidia spp. and were examined for parasitoid-related mortality. The trichogrammatid Trichogrammatoidea sp. nr. lutea was obtained from eggs of Mussidia fiorii. A braconid egg-larval parasitoid, Phanerotoma sp., was reared from the larvae of unknown species of Mussidia (which we are referring to as Mussidia “madagascariensis”, Mussidia “quanzensis”) and M. fiorii, while the bethylid Goniozus sp. and the braconid Apanteles sp. were obtained from Mussidia nr. nigrivenella. Moreover, the ichneumonid larval parasitoid Syzeuctus sp. was obtained from M. fiorii, while the tachinid Leskia sp. was obtained from Mussidia “madagascariensis”. Overall, mortality caused by parasitoids was negligible; hence they were not considered key mortality factors in the population dynamics of the Mussidia spp. in Kenya.  相似文献   

Vector control and foliar nutrition to maintain economic sustainability of bearing citrus in Florida groves affected by huanglongbing     

Philip A Stansly  H Alejandro Arevalo  Jawwad A Qureshi  Moneen M Jones  Katherine Hendricks  Pamela D Roberts  Fritz M Roka 《Pest management science》2014,70(3):415-426

  相似文献