Microbial community changes in heathland soil communities along a geographical gradient: interaction with climate change manipulations     

Alwyn Sowerby  Bridget Emmett  Albert Tietema  Marc Estiarte  Steven Hughes 《Soil biology & biochemistry》2005,37(10):1805-1813

Climate change constitutes a serious threat for European heathlands as unlike other sources of damage, such as over-grazing, local remediation is not a possibility. Within the large pan-European projects, CLIMOOR and VULCAN, the effect of periodic drought and increased temperature were investigated in four heathland ecosystems along a geographical and climatic gradient across Europe. Fluorogenically labelled substrates for four enzymes (glucosidase, sulphatase, phosphatase, leucine amino peptidase) were used to measure extra-cellular enzyme activity in soil samples from each of the CLIMOOR sites. Microbial extra-cellular enzyme production is linked to microbial activity as well as soil physico-chemical properties, making soil enzymes one of the more reactive components of terrestrial ecosystems and potentially excellent indicators of soil microbial functional status and diversity.Across all sites and over all the substrates, organic matter content was exponentially, inversely related to enzyme activity. Although the increase in temperature produced by the CLIMOOR roofs was small (on average 0.9 °C), this was sufficient to increase enzyme activity in all sites (on average by 45%). The increase was within the range of seasonal variability at each of the sites. The effect of drought on enzyme activity was more pronounced in the Northern European sites than the southern European, and most moisture limited, site. This suggests that the effect of temperature increases may be observed across all regions; however, the soils of northern Europe may be more sensitive to changes in rainfall patterns than more moisture limited Southern European soils.  相似文献   

Seasonal patterns of root-surface phosphatase activities in a Mediterranean shrubland. Responses to experimental warming and drought   总被引：2，自引：0，他引：2  

Jordi Sardans  Josep Peñuelas  Marc Estiarte 《Biology and Fertility of Soils》2007,43(6):779-786

Mediterranean ecosystems are water limited and the current general circulation Models (GCM) and ecophysiological models forecast a warming and a further increase of drought in the next decades. A stronger water stress can decrease the capacity for nutrient absorption by plants. We conducted a field experiment to simulate forecasted drought and warming in a Mediterranean calcareous shrubland to assess the performance of root-surface phosphatase activities of the dominant shrub Globularia alypum. These enzyme activities were higher in autumn and spring, when the climate conditions were optimal for plant activity, than in summer or winter, when there was either lack of water or cold temperatures. A decrease in soil moisture in drought plots decreased root-surface phosphatase activity (29% in summer and 25% in autumn). The decrease in root-surface phosphatase activity in drought plots coincided with a decrease in P leaf concentrations and P accumulation in aboveground biomass and loss of photosynthetic capacity of some dominant shrub species of this ecosystem, and with a tendency to increase total soil-P. These results suggest that the expected drier conditions in this Mediterranean shrubland in the next decades will slow down the P uptake by plants, thereby, diminishing the P contents in biomass and increasing total P contents in soil in non-available forms and that this can be, in part, attributable to a result of the decrease in root-surface phosphatase activity.  相似文献   

Central Venous Pressure Measurements in the Caudal Vena Cava of Sedated Cats     

Roslyn G. Machon B.V.Sc.  M.V.Sc.  M.S.    Marc R. Raffe D.V.M. M.S.  Elaine P. Robinson B.Vet.Med.  M.V.Sc. 《Journal of Veterinary Emergency and Critical Care》1995,5(2):121-129

The caudla vena cava (CVA) was evaluated as an laternative site for the measurement of central venous pressure (CPV) in six healthy, sedated (ketamine 10 mg/km, midazolam 0.1 mg/kg, and atropine 0.04 mg/kg IM) cats. The CVC was cathererized via medial saphenous puncture, and estimates of CPV from this site compared to those obtained via a jugular catheter. Simulataneous CPV values were recorded electronically (mmgh), via calibrated pressure transducer positioned at the level of the manubrium in cats in lateral recumbency. Five readings, performed at 1 minute intervals, were collected from the jugular and CVC catheters at rest (baseline) and following a rapid fluid bolus. Twenty-four hours later, cats were resedated, baseline measurements repeated, and CVPs recorded following a rapid, 25% whole-blood volume bleed. CVP measurements from the jugular and CVC were statistically compared using repeated measures ANOVA (p<0.05). There were no significant differences between the two sites in the baseline and bleed trials. Significant defferences between jugular and CVC CVPs were noted at 1 and 2 minutes following the fluid bolus. It was concluded that CVC is an alternative site for measurement of CPV in sedated cats.  相似文献   

Implications of biotechnology, risk assessment, and communications for the safety of foods of animal origin.     

G R Acuff  R A Albanese  C A Batt  D L Berndt  F M Byers  B E Dale  J H Denton  R L Fuchs  B Gastel  N D Heidelbaugh 《Journal of the American Veterinary Medical Association》1991,199(12):1714-1721

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Toxicological problems with residues of chemical compounds in animal feed. 2. Measures and regulations concerning toxic compounds in animal feed to safeguard animal production and to protect human health     

M Kühnert  V Fuchs  S Golbs  U Knoll  P Eichelberger 《Monatshefte für Veterin?rmedizin》1973,28(2):41-45

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Pharmacologic and toxicologic properties of humic acids and their activity profile for veterinary medicine therapy     

M Kühnert  V Fuchs  S Golbs 《DTW. Deutsche tier?rztliche Wochenschrift》1989,96(1):3-10

Humic acids derive from a class of natural substances in humic substances. The chemical properties of certain defined humic acid products enable their application in diseases of the digestive system of mammals when combined with metabolic disorders, especially in rearing age. The simple administration (via feed), their exceptional safety and the absence of side effects (e. g. allergy, resistance) as well as no residue formation in animal derived products allow a broad application of these substances in veterinary medicine, even when regarding ecotoxicological aspects.  相似文献   

Detection of Escherichia coli strains producing cytotoxic necrotizing factor type two (CNF2) by enzyme-linked immunosorbent assay     

Eric Oswald  Marc Tabouret  Roger Boivin  Jean De Rycke 《Veterinary microbiology》1994,40(3-4):209-218

Sheep and rabbit antisera were produced against lysates of E. coli strain 711 (pVir). This K-12 strain carries the Vir plasmid which codes for Cytotoxic Necrotizing Factor type 2 (CNF2). Immunoglobulin G (IgG) fractions of both immune sera were subsequently purified by a two-step precipitation method. To increase the specificity for CNF2, the sheep IgG preparation was extensively adsorbed against both a sonicated extract of isogenic K-12 strain 711 and intact phenol-treated cells of vaccine strain 711 (pVir). An enzyme-linked immunosorbent assay (ELISA) was developed to detect clinical isolates of E. coli producing CNF2, using the final preparations of rabbit and sheep IgG in a double sandwich technique. The results obtained with this CNF2-ELISA were compared to those obtained with the conventional HeLa cell cytotoxicity assay. The testing of 133 E. coli strains (49 CNF2 positive strains and 84 negative strains) resulted in no false-negative and no false-positive. Therefore, the CNF2-ELISA offers a good alternative to the HeLa cell culture assay for the detection of CNF2-producing strains where facilities for and experience with cell cultures is lacking.  相似文献   

Bacteriekanker bij Steenvruchten     

A. Fuchs 《European journal of plant pathology / European Foundation for Plant Pathology》1957,63(2):33-44

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Resistance to triforine: A nonexistent problem?     

A. Fuchs  S. P. de Ruig  J. M. van Tuyl  F. W. de Vries 《European journal of plant pathology / European Foundation for Plant Pathology》1977,83(1):189

Permanent resistance to triforine in Cladosporium cucumerinum was obtained after UV irradiation of spore suspensions and selection of resistant strains in the presence of triarimol or triforine. About 50 strains were examined for mycelial growth on malt agar, viability upon routine subculturing, growth and inhibition by triforine in thin-layer chromatographic bioassays, and virulence towards cucumber seedlings. In addition, sporulation and spore germination, as well as effects of ergosterol were investigated in a restricted number of strains. Although all strains differed considerably from each other in these characteristics, they were quite similar in a reduced overall-fitness. These triforine-resistant mutants of C. cucumerinum might, therefore, have a greatly reduced chance of survival in competition with the wild-type strain, as was actually demonstrated for two strains in greenhouse experiments with mixed-inoculations of cucumber seedlings. Such a reduced chance of survival might also explain why under practical conditions development of resistance to triforine has not been observed yet.The triforine-resistant C. cucumerinum strains showed cross-resistance to a number of systemic fungicides known or supposed to inhibit ergosterol biosynthesis, viz. Denmert, fenarimol, imazalil, triadimefon and triarimol. The practical implications and potential hazards of such cross-resistance for the use of already established fungicides are discussed.  相似文献   

The digestibility of crude nutrients in horses. 1. Methods of determining digestibility     

R Fuchs  H Militz  M Hoffmann 《Archives of Animal Nutrition》1987,37(3):235-246

The ascertainment of the digestibility of crude nutrients in rations for horses requires the inclusion of movement-based performance as influencing factor. Under the consideration of this requirement, indicator methods gain significance in comparison with the standard method of collecting faeces completely. In two experiments the digestion of the crude nutrients in rations for horses was tested according to the standard method (complete collection of faeces) and the indicator method 4 N HCl-insoluble ash). According to the indicator method the digestibility of crude nutrients was slightly higher, the differences to the values of the standard method were statistically insignificant. Under consideration of the inhomogeneity of horse faeces and the possibility of doing without the complete collection of faeces, the indicator method with 4 N HCl-insoluble ash is to be preferred to the standard method. The analysis of air-dried faeces connected with the indicator method resulted in improved reproducibility due to the significantly better homogeneity. A recommendation is made for carrying out digestibility experiments with horses, in which the 4 N HCl indicator method is used.  相似文献