Non‐target screening of leaf litter‐derived dissolved organic matter using liquid chromatography coupled to high‐resolution mass spectrometry (LC‐QTOF‐MS)     

Olaf Brock  Rick Helmus  Karsten Kalbitz  Boris Jansen 《European Journal of Soil Science》2020,71(3):420-432

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Variations in mucous cell numbers in gills of Atlantic salmon (Salmo salar) presmolt in commercial freshwater farms in Norway     

David Persson  Hvard Bjrgen  Alexander Figenschou  Linn‐Anett Hillestad  Erling Olaf Koppang  Ane Ndtvedt  Marit Stormoen 《Journal of fish diseases》2021,44(1):25-32

Fish gills are heavily exposed to the external milieu and may react against irritants with different cellular responses. We describe variations in mucous cell counts in gills from healthy Atlantic salmon (Salmo salar) presmolts in five recirculating aquaculture system (RAS) farms and one flow‐through farm. Based on certain criteria, mucous cells were histologically quantified in a defined lamellar region of the gills and the counts were analysed. Immunohistochemistry (IHC) was used to investigate epithelial responses. The median number of total mucous cells in the defined region was 59 per fish. Between the farms, the medians varied from 31 to 101 with the lowest in the flow‐through farm. A regression model was fitted with “total mucous cells” as the dependent variable and with “fish length” and “fish farm” as independent variables. The proportion of variation in mucous cell counts explained by the model was twice as high when “fish farm” was included compared to only “fish length.” IHC revealed proliferative responses in coherence with high mucous cell numbers. Conclusively, the variation in mucous cell counts depends on combined farm‐related factors. Establishing a baseline for mucous cell counts is fundamental in the development of high‐throughput monitoring programmes of gill health in farmed fish.  相似文献   

Iron-source preference of Staphylococcus aureus infections     

Skaar EP  Humayun M  Bae T  DeBord KL  Schneewind O 《Science (New York, N.Y.)》2004,305(5690):1626-1628

Although bacteria use different iron compounds in vitGro, the possibility that microbes distinguish between these iron sources during infection has hitherto not been examined. We applied stable isotope labeling to detect source-specific iron by mass spectrometry and show that Staphylococcus aureus preferentially imports heme iron over transferrin iron. By combining this approach with computational genome analysis, we identified hts (heme transport system), a gene cluster that promotes preferred heme iron import by S. aureus. Heme iron scavenging by means of hts is required for staphylococcal pathogenesis in animal hosts, indicating that heme iron is the preferred iron source during the initiation of infection.  相似文献   

Mediastinal Schwannoma in a horse-cytologic,histologic, and immunochemical evaluation     

Andreasen CB  Hedstrom OR  Allison P 《Veterinary clinical pathology / American Society for Veterinary Clinical Pathology》1993,22(2):54-59

A 31-kg mediastinal mass from a 24-year-old horse is described. Cytologic imprints contained numerous spindle cells with indistinct cytoplasm and multiple foci of palisading nuclei. Histologic sections had these same characteristics and areas of central fibrillar material between palisading nuclei (Verocay bodies). Within histologic sections, spindle cell cytoplasm had positive immunoreactivity for vimentin and S-100, whereas immunoreactivity was not detected for desmin and cytokeratin. Cytologic, histologic, and immunochemical evaluation confirmed a diagnosis of solitary schwannoma.  相似文献   

Anthropogenic landscape changes in Central Europe and the role of bioindication   总被引：4，自引：2，他引：2  

Olaf Bastian  Arnd Bernhardt 《Landscape Ecology》1993,8(2):139-151

Anthropogenic landscape changes in Central Europe occurred in several stages. Characteristic features include an acceleration in the sequence of changes, a continual increase in the scope and complexity of ecologic problems, growing destabilization of the natural household and a rising proportion of irreversible changes.Various bioindication techniques are excellently suited for detecting and evaluating landscape changes, as reflected in a large number of case studies. Of these, a number are classified by the authors according to the following criteria: landscape features/components, structure of the test area, and time framework for the studies.Thorough changes must be brought about in man's relation with nature to remedy the aggrevated environmental situation, with these priorities: making human thinking and action compatible with the environment, transforming material production along ecological lines, and applying ecological principles to landscape management, for example in the form of landscape planning.  相似文献   

ULTRASONOGRAPHIC DIAGNOSIS: CRANIAL VENA CAVA THROMBOSIS IN A COW     

Aloisio C.D.  Bueno  Med  Vet  MS  Barbara J.  Watrous  DVM  Jill E.  Parker  VMD  Olaf R.  Hedstrom  DVM  Phd 《Veterinary radiology & ultrasound》2000,41(6):551-553

A 5-year-old Hereford cow was donated to Oregon State University, College of Veterinary Medicine. Two weeks before presentation the cow was treated by a left-flank laparotomy to correct a uterine torsion that revealed an excessive amount of abdominal fluid and a full term dead fetus. Ultrasonographic evaluation of the right cranioventral thoracic cavity was performed owing to physical examination (muffled heart sounds, areas of silence) and thoracocentesis findings suggestive of pleuritis. Ultrasonography revealed hypoechoic pleural effusion and a mass of mixed echogenicity visible within the right atrial lumen extending into the cranial vena cava. A diagnosis of cranial vena cava thrombosis was demonstrated at necropsy. The clinical, ultrasonographic, and pathological features of this less common condition (cranial vena cava thrombosis) in cattle are discussed.  相似文献   

Factors associated with Echinococcus multilocularis infection in coyotes in southern Ontario     

Jonathon D. Kotwa  David L. Pearl  Mats Isaksson  Claire M. Jardine  Olaf Berke  Nicola J. Mercer  Eva Osterman‐Lind  Andrew S. Peregrine 《Zoonoses and public health》2020,67(5):546-553

Echinococcus multilocularis was recently reported in wild canids across southern Ontario, a newly recognized endemic area in Canada. In such areas, a comprehensive understanding of factors associated with infection in definitive hosts (wild canids) is critical for mitigating risk of transmission to humans. However, little is known about the transmission dynamics of the parasite in definitive hosts for this region. A study was therefore carried out to investigate the association of host‐level (sex, body condition), environmental (southern Ontario region, land cover), temporal (season, hunting season, calendar year) and extraneous factors (submitter type) with E. multilocularis infection in coyotes in southern Ontario. Between November 2015 and March 2017, 416 coyotes were collected from across the region as part of a study that investigated the prevalence and distribution of the parasite in wild canids; approximately 24% of coyotes were positive for E. multilocularis. Associations between infection and factors of interest were assessed via a mixed‐effects logistic regression model with a random intercept for submitter to account for clustering. Coyotes with poor body condition were at greater odds of E. multilocularis infection than those in good condition (odds ratio [OR] 2.14; 95% CI: 1.08–4.26; p = .030). A negative association was observed between infection in coyotes and the proportion of natural land in a coyote's estimated home range (OR: 0.67; 95% CI: 0.52–0.85; p = .001). Coyotes from the western region of southern Ontario had lower odds of infection compared to coyotes from the central region (OR: 0.26; 95% CI: 0.12–0.55; p < .001). These results can be used to help guide future public health prevention strategies for human alveolar echinococcosis.  相似文献   

Multiple causes of high extinction risk in large mammal species   总被引：2，自引：0，他引：2  

Cardillo M  Mace GM  Jones KE  Bielby J  Bininda-Emonds OR  Sechrest W  Orme CD  Purvis A 《Science (New York, N.Y.)》2005,309(5738):1239-1241

Many large animal species have a high risk of extinction. This is usually thought to result simply from the way that species traits associated with vulnerability, such as low reproductive rates, scale with body size. In a broad-scale analysis of extinction risk in mammals, we find two additional patterns in the size selectivity of extinction risk. First, impacts of both intrinsic and environmental factors increase sharply above a threshold body mass around 3 kilograms. Second, whereas extinction risk in smaller species is driven by environmental factors, in larger species it is driven by a combination of environmental factors and intrinsic traits. Thus, the disadvantages of large size are greater than generally recognized, and future loss of large mammal biodiversity could be far more rapid than expected.  相似文献   

Determination of 28 Elements in Aquatic Moss Fontinalis Antipyretica Hedw. and Water from the Upper Reaches of the River Nysa (CZ,D), by ICP-MS,ICP-OES and AAS     

Vazquez  María D.  Wappelhorst  Olaf  Markert  Bernd 《Water, air, and soil pollution》2004,152(1-4):153-172

The concentrations of 28 elements in samples of the bryophyte F. antipyretica Hedw collected from various sites on the upper reaches of the River Nysa and its main tributaries were determined. These results were compared with similar analyses of water samples collected at the same sites. So, it was possible to determine the elemental composition of the water both directly and indirectly, using a bioindicator organism. Analyses were carried out using different instrumental techniques (ICP-MS, ICP-OES, AAS), some elements being analysed by both ICP-MS and ICP-OES. Functional regression analysis showed that for some of these elements, namely Al, Ba, Fe, Sr and Ti in moss, and Ba, Ca and Zn in water samples, there was no significant difference (p < 0.05) in the concentrations determined by both techniques. The coefficients of correlation moss/water for each element were calculated, but they were in general low. However the coefficients of correlation between different elements were in general good. Finally, the elemental concentrations in the aquatic moss were also used to assess the level of contamination in the area of study, through the calculation of CF (Contamination Factor) values.  相似文献   

Endogeic earthworms alter carbon translocation by fungi at the soil-litter interface     

Olaf Butenschoen  Christian Poll  Ellen Kandeler  Stefan Scheu 《Soil biology & biochemistry》2007,39(11):2854-2864

The effect of endogeic earthworms (Octolasion tyrtaeum (Savigny)) on the translocation of litter-derived carbon into the upper layer of a mineral soil by fungi was investigated in a microcosm experiment. Arable soil with and without O. tyrtaeum was incubated with ¹³C/¹⁵N-labelled rye leaves placed on plastic rings with gaze (64 μm mesh size) to avoid incorporation of leaves by earthworms. The plastic rings were positioned either on or 3 cm above the soil surface, to distinguish between biotic and chemical/physical translocation of nutrients by fungi and leaching.Contact of leaves to the soil increased ¹³C translocation, whereas presence of O. tyrtaeum reduced the incorporation of ¹³C into the mineral soil in all treatments. Although biomass of O. tyrtaeum decreased during the experiment, more ¹³C and ¹⁵N was incorporated into earthworm tissue in treatments with contact of leaves to the soil. Contact of leaves to the soil and the presence of O. tyrtaeum increased cumulative ¹³CO₂-C production by 18.2% and 14.1%, respectively.The concentration of the fungal bio-indicator ergosterol in the soil tended to be increased and that of the fungal-specific phospholipid fatty acid 18:2ω6 was significantly increased in treatments with contact of leaves to the soil. Earthworms reduced the concentration of ergosterol and 18:2ω6 in the soil by 14.0% and 43.2%, respectively. Total bacterial PLFAs in soil were also reduced in presence of O. tyrtaeum, but did not respond to the addition of the rye leaves. In addition, the bacterial community in treatments with O. tyrtaeum differed from that without earthworms and shifted towards an increased dominance of Gram-negative bacteria.The results indicate that litter-decomposing fungi translocate litter-derived carbon via their mycelial network in to the upper mineral soil. Endogeic earthworms decrease fungal biomass by grazing and disruption of fungal hyphae thereby counteracting the fungal-mediated translocation of carbon in soils.  相似文献