Scale-dependent importance of environment, land use and landscape structure for species richness and composition of SE Norwegian modern agricultural landscapes     

Rune H. Økland  Harald Bratli  Wenche E. Dramstad  Anette Edvardsen  Gunnar Engan  Wendy Fjellstad  Einar Heegaard  Oddvar Pedersen  Heidi Solstad 《Landscape Ecology》2006,21(7):969-987

Knowledge of variation in vascular plant species richness and species composition in modern agricultural landscapes is important for appropriate biodiversity management. From species lists for 2201 land-type patches in 16 1-km² plots five data sets differing in sampling-unit size from patch to plot were prepared. Variation in each data set was partitioned into seven sources: patch geometry, patch type, geographic location, plot affiliation, habitat diversity, ecological factors, and land-use intensity. Patch species richness was highly predictable (75% of variance explained) by patch area, within-patch heterogeneity and patch type. Plot species richness was, however, not predictable by any explanatory variable, most likely because all studied landscapes contained all main patch types – ploughed land, woodland, grassland and other open land – and hence had a large core of common species. Patch species composition was explained by variation along major environmental complex gradients but appeared nested to lower degrees in modern than in traditional agricultural landscapes because species-poor parts of the landscape do not contain well-defined subsets of the species pool of species-rich parts. Variation in species composition was scale dependent because the relative importance of specific complex gradients changed with increasing sampling-unit size, and because the amount of randomness in data sets decreased with increasing sampling-unit size. Our results indicate that broad landscape structural changes will have consequences for landscape-scale species richness that are hard or impossible to predict by simple surrogate variables.  相似文献   

West Nile virus infection in reindeer (Rangifer tarandus).     

Mitchell V Palmer  William C Stoffregen  Douglas G Rogers  Amir N Hamir  Juergen A Richt  Douglas D Pedersen  W Ray Waters 《Journal of veterinary diagnostic investigation》2004,16(3):219-222

West Nile virus (WNV) infection in 4 reindeer (Rangifer tarandus) resulted in lymphohistiocytic encephalomyelitis within the medulla oblongata and cervical spinal cord. Immunohistochemistry revealed WNV antigen within neurons and among mononuclear cell infiltrates. These represent the first known cases of clinical WNV infection in Cervidae. Clinical signs and lesions were similar to those described in horses. Nucleotide sequence of a 768-bp region of the WNV E-glycoprotein gene revealed 1 nucleotide mutation, which resulted in a single amino acid substitution from a serine to a glycine (position 227 of E-glycoprotein) when compared with the prototype WNV-NY99 strain (isolated from Bronx zoo flamingo 382-99).  相似文献   

Sulfated glycosaminoglycans and collagen in two bovine muscles (M. Semitendinosus and M. Psoas major) differing in texture     

Pedersen ME  Kolset SO  Sørensen T  Eggen KH 《Journal of agricultural and food chemistry》1999,47(4):1445-1452

M. semitendinosus (ST) and M. psoas major (PM) were used as models for tough and tender meat to study a possible role of sulfated glycosaminoglycans (GAGs) for muscle tenderness. The difference in texture was confirmed by Warner Bratzler shear force measurements. No significant difference in total amount of GAGs in the muscles was found. In contrast, a significant difference in the ratio of GAG/collagen was found between the two muscles. After separation of the GAGs by density gradient ultracentrifugation and ion-exchange chromatography, dermatan sulfate (DS), keratan sulfate (KS), chondroitin sulfate (CS), and heparan sulfate (HS) were identified by cellulose acetate electrophoresis after use of specific enzymes and chemical methods. The content of DS was higher in the tougher muscle (ST) than in PM, and the difference in DS content was statistically significant. Furthermore, a significant difference in the GAG composition pattern of the two muscles was found. The yield of GAGs extracted from the muscles was 77% for ST and 87% for PM. The residue after extraction was further analyzed and found to contain mainly HS. Immunohistochemical studies using antibodies against CS/DS showed a staining pattern of the perimysium of ST different from that of PM.  相似文献   

Comparison between microscopic and automated differential leukocyte counts in the silver fox (Vulpes vulpes) and the blue fox (Alopex lagopus)     

Moe RO  Bakken M  Brun-Hansen H  Adnøy T  Morberg H 《Veterinary clinical pathology / American Society for Veterinary Clinical Pathology》1999,28(2):65-70

Differential leukocyte (WBC) counts in blood from clinically healthy silver foxes (n=32) and blue foxes (n=37) obtained from an automated hematology analyzer (Technicon H*1 Hematology System) with canine software were compared with microscopic differential WBC counts (M-diff). There was good agreement between the automated differential cell count (A-diff) and the M-diff for neutrophil and lymphocyte percentages. The correlation was lower for monocyte percentages and variable for eosinophil percentages. There was no significant difference between the A-diff and M-diff in either fox species. The A-diff counts were very precise, and may be a good alternative to the traditional M-diff for screening populations of clinically healthy foxes or for studies on stress and animal welfare. Intercept values, however, indicated a constant bias that must be taken into account before interpreting results based on different methods of analysis  相似文献   

Vibrios associated with mortality in cultured plaice Pleuronectes platessa fry     

Pedersen K  Austin B  Austin DA  Larsen JL 《Acta veterinaria Scandinavica》1999,40(3):263-270

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Effects of storage time on chemistry results from canine whole blood,heparinized whole blood,serum and heparinized plasma     

Thoresen SI  Havre GN  Morberg H  Mowinckel P 《Veterinary clinical pathology / American Society for Veterinary Clinical Pathology》1992,21(3):88-94

The stability and storage characteristics of 24 blood constituents from dogs including nine enzymes (ALP, ALT, amylase, AST, CK, GGT, GLDH, LDH, lipase), 15 metabolites and minerals (albumin, bile acids, bilirubin, calcium, cholesterol, creatinine, fructosamine, glucose, magnesium, phosphate, potassium, protein, sodium, triglycerides, urea) were studied. Conditions studied included storing of nonanticoagulated and heparinized whole blood for 3 days (Part A), and storing of serum and heparinized plasma for 3 days (Part B). The storage temperature for both studies was +4 degrees C from day 0 to day 1, and +20 degrees C, from day 1 to day 2 and 3. Eight of 24 analytes showed no significant differences (p > 0.05) for three days in whole blood. However, the stability of all 24 analytes greatly improved by storing serum or heparinized plasma compared to nonanticoagulated or heparinized whole blood. In stored serum or heparinized plasma, 20 of 24 analytes showed no significant differences (p < 0.05) for 3 days. Nine of 24 analytes showed significant differences (p < 0.05) between serum and heparinized plasma, where CK, LDH, GGT, and potassium showed differences of possible clinical importance. This study strongly supports the practice of separating serum/plasma from clot/cells as promptly as possible to achieve improved stability for most analytes under test.  相似文献   

Isolation of putative probionts from cod rearing environment     

Lauzon HL  Gudmundsdottir S  Pedersen MH  Budde BB  Gudmundsdottir BK 《Veterinary microbiology》2008,132(3-4):328-339

Survival problems are encountered at early stages of intensive fish rearing and antibiotics are widely used to remedy the situation. Probiotics may provide a potential alternative method to protect larvae from opportunistic and pathogenic bacteria and promote a balanced environment. This study was designed to search for new probiotics to target this critical period in cod rearing. Potential probionts were selected from the natural microbiota of cod aquacultural environment. The selection was based on several criteria: pathogen inhibition potential, growth characteristics, strain identification, metabolite production and adhesion to fish cell lines. Our study demonstrated that 14% of screened bacteria (n=188) had antagonistic properties towards fish pathogens. The majority of these isolates were Gram-positive (81%), belonging to Firmicutes (69.2%) and Actinobacteria (11.5%) phyla based on 16S rRNA gene sequencing. Only 6 (3.2%) of 188 isolates could inhibit all three pathogens tested: Vibrio anguillarum, Aeromonas salmonicida subsp. achromogenes and Vibrio salmonicida. Differences observed in activity intensity and spectrum among inhibitory isolates emphasise the need to develop probiotic mixtures for efficient prophylactic methods. Comparison of growth behaviour of inhibitory isolates and pathogens at cod rearing temperatures, metabolite production and adhesion capacity were considered for final probiont selection. Four promising isolates that could be used as a mixed supplement to rearing water were identified as putative probiotic bacteria. This study emphasises the importance and potential of lactic acid bacteria in aquaculture.  相似文献   

Simulating nitrate retention in soils and the effect of catch crop use and rooting pattern under the climatic conditions of Northern Europe     

A. Pedersen    K. Thorup-Kristensen  & L. S. Jensen 《Soil Use and Management》2009,25(3):243-254

This model analysis of catch crop effects on nitrate retention covered three soil texture classes (sand, loamy sand, sandy loam) and three precipitation regimes in a temperate climate representative of northern Europe (annual precipitation 709–1026 mm) for a period of 43 years. Simulations were made with two catch crops (ryegrass and Brassica) with different rooting depths, and soil N effects in the next spring were analysed to 0.25, 0.75 and 2.0 m depth to represent the catch crop effect on following crops with different rooting depths. Nitrate retained without a catch crop was generally located in deeper soil layers. In the low precipitation regime the overall fraction of nitrate retained in the 0–2.0 m soil profile was 0.23 for the sandy soil, 0.69 for the loamy sand and 0.81 for the sandy loam. Ryegrass reduced leaching losses much less efficiently than Brassica, which depleted nitrate in the 0–0.75 m soil layer more completely, but also in the deeper soil layer, which the ryegrass could not reach. A positive N effect (N_eff, spring mineral N availability after catch crop compared with bare soil) was found in the 0–0.25 m layer (that is shallow rooting depth of a subsequent main crop) in all three soil texture classes, with on average 10 kg N/ha for ryegrass and 34 kg N/ha for Brassica. Considering the whole soil profile (0–2.0 m deep rooting of next crop), a positive N_eff was found in the sand whereas generally a negative N_eff was found in the loamy sand and especially the sandy loam. The simulations showed that for shallow‐rooted crops, catch crop N_eff values were always positive, whereas N_eff for deeper‐rooted crops depended strongly on soil type and annual variations in precipitations. These results are crucial both for farmers crop rotation planning and for design of appropriate catch crop strategies with the aim of protecting the aquatic environment.  相似文献   

Supplementing enzymes to extruded,soybean‐based diet improves breakdown of non‐starch polysaccharides in rainbow trout (Oncorhynchus mykiss)          下载免费PDF全文

J. Dalsgaard  K.E. Bach Knudsen  V. Verlhac  K.S. Ekmann  P.B. Pedersen 《Aquaculture Nutrition》2016,22(2):419-426

Plant‐based feed ingredients typically contain remnants of dietary fibres [DF; non‐starch polysaccharides (NSP) and lignin] that have various antinutritive effects in carnivorous fish. Exogenous enzymes have been shown to improve the apparent digestibility coefficients (ADC) of plant‐based diets presumably by assisting in the breakdown of NSP. This study examined the effects on NSP degradation when supplementing β‐glucanase, xylanase, protease or a mix of the three enzymes to an extruded, juvenile rainbow trout (Oncorhynchus mykiss) diet containing 344 g kg^?1 de‐hulled, solvent‐extracted soybean meal (SBM). The NSP content in the non‐supplemented control diet and in faecal samples from the dietary treatment groups was analysed to determine the recovery/apparent digestibility of cellulose and total non‐cellulosic polysaccharide (T‐NCP) sugar monomers. The enzymes had significant, positive effects at the pH range and temperature prevailing in the gastrointestinal tract: β‐glucanase improved the ADC of mannose, galactose and uronic acids; xylanase and protease improved the ADC of xylose; and protease furthermore improved the ADC of mannose and uronic acids. There were no effects when supplementing all three enzymes together. In conclusion, exogenous enzymes may potentially be applied to fish feed containing SBM, assisting in the breakdown of NSP and alleviating some of the antinutritive effects.  相似文献   

Next Generation Sequencing Bulk Segregant Analysis of Potato Support that Differential Flux into the Cholesterol and Stigmasterol Metabolite Pools Is Important for Steroidal Glycoalkaloid Content     

Kacper Piotr Kaminski  Kirsten Kørup  Mathias Neumann Andersen  Mads Sønderkær  Mette Sondrup Andersen  Hanne Grethe Kirk  Kåre Lehmann Nielsen 《Potato Research》2016,59(1):81-97

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