Instrumented cervical fusion in nine dogs with caudal cervical spondylomyelopathy     

Tjarda E. Reints Bok  Koen Willemsen  Mattie H. P. van Rijen  Guy C. M. Grinwis  Marianna A. Tryfonidou  Bjrn P. Meij 《Veterinary surgery : VS》2019,48(7):1287-1298

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Trophic relationships between a native and a nonnative predator in a system of natural lakes     

Michael H. Meeuwig  Christopher S. Guy  Wade A. Fredenberg 《Ecology of Freshwater Fish》2011,20(2):315-325

Abstract – Bull trout, a species of char listed as threatened under the US Endangered Species Act, have been displaced from portions of their historic range following the introduction of nonnative lake trout. It has been suggested that competitive exclusion as a result of trophic overlap between bull trout and lake trout may be the causal mechanism associated with displacement of bull trout. This study used stable isotope data to evaluate trophic relationships among native bull trout, nonnative lake trout and other fishes in seven lakes in Glacier National Park (GNP), Montana. Bull trout and lake trout had greater δ¹⁵N values relative to other fishes among lakes (δ¹⁵N ≥ 3.0‰). Lake trout had greater δ¹⁵N values relative to bull trout (δ¹⁵N = +1.0‰). Bull trout had greater δ¹³C values relative to lake trout in six of the seven lakes examined. Although both bull trout and lake trout had greater δ¹⁵N values relative to other fishes within lakes in GNP, differences in δ¹⁵N and δ¹³C between bull trout and lake trout suggest that they are consuming different prey species or similar prey species in different proportions. Therefore, displacement of bull trout as a direct result of complete overlap in food resource use is not anticipated unless diet shifts occur or food resources become limiting. Additionally, future studies should evaluate food habits to identify important prey species and sources of partial dietary overlap between bull trout and lake trout.  相似文献   

Physiological recovery of freezer-stored white and Engelmann spruce seedlings planted following different thawing regimes     

Edith L. Camm  Robert D. Guy  David S. Kubien  Darren C. Goetze  Salim N. Silim  Philip J. Burton 《New Forests》1995,10(1):55-77

Logistic problems of large-scale reforestation necessitate freezer-storage of conifer seedlings. Frozen stock is typically thawed slowly at low temperatures for up to several weeks before shipping to the plantation site, but the necessity of this practice is questionable. Experiments were conducted to study effects of different thawing regimes on photosynthetic recovery, frost hardiness, water relations and growth initiation in interior spruce (white spruce (Picea glauca (Moench) Voss) and Engelmann spruce (Picea engelmannii Parry) hybrid complex). One year-old container-grown seedlings were planted after 9 days post-storage thawing at 5–15 °C or still frozen, directly from the freezer. During a 29 day observation period after planting, both groups showed changes in xylem water potential (_w), carbon fixation (A), stomatal conductance (g _s ), chlorophyll a fluorescence and xanthophyll cycle pigments. Treatment differences in fluorescence and pigments peaked within one hour after planting. All differences in _w, A, g _s , ratio of internal to external CO₂ concentration (C_i/C_a), fluorescence, pigments and root number disappeared after 5 to 8 days. Terminal bud burst occurred 2.6 days earlier in the pre-thawed seedlings. When seedlings were rapidly thawed in the dark at 21 °C they achieved maximum _w (–0.2 MPa) in 3–4 hour. When evaluated 45 min after planting, A, g _s , C_i/C_a and fluorescence values of rapidly thawed seedlings were intermediate between those for seedlings planted frozen or after 9 days slow thawing, showing that the recovery process was well underway a few hours after removal from the freezer. These results suggested that a suitable on-site operational protocol for rapid thawing might be to lay frozen bundles on the ground at ambient temperature overnight. In field trials of this method, rapidly thawed seedlings broke bud 3.3 days later than slowly thawed stock and also had greater frost hardiness at time of planting. Height, shoot and root mass did not differ after 3 months growth.  相似文献   

Expression of garlic leaf lectin under the control of the phloem-specific promoter Asus1 from Arabidopsis thaliana protects tobacco plants against the tobacco aphid (Myzus nicotianae)     

Sadeghi A  Broeders S  De Greve H  Hernalsteens JP  Peumans WJ  Van Damme EJ  Smagghe G 《Pest management science》2007,63(12):1215-1223

BACKGROUND: To check for correlation between the insecticidal properties and the specificity of lectins, a comparative study was made of the insecticidal activities of two garlic lectins with different biological activities.RESULTS: The insecticidal activity of the garlic (Allium sativum L.) leaf lectin ASAL and bulb lectin ASAII towards the tobacco aphid Myzus nicotianae Blackman was studied using bioassays with transgenic tobacco (Nicotiana tabacum L. cv. Wisconsin 38). Bioassays were started with newborn nymphs of the tobacco aphid. Although during the first 7-8 days when nymphs developed to adults there were no apparent effects, part of the nymphal population was found to develop into winged (alate) forms. Later it became clear that transgenic plants expressing ASAL and ASAII had a significant effect on the reproduction capacity of the resulting adults, with a reduction of up to 40%. Different life table parameters such as prereproductive time, intrinsic rate of natural increase, generation time and doubling time were significantly affected (P < 0.05) in aphids grown on transgenic plant material expressing ASAL and ASAII.CONCLUSION: Bioassays with tobacco plants expressing ASAL and ASAII demonstrated a significant impact on the population growth of M. nicotianae. Therefore, both lectins can be considered as valuable candidate aphid control agents.  相似文献   

A mixed methodology framework for the assessment of the Voluntary Initiative     

Garrod GD  Garratt JA  Kennedy A  Willis KG 《Pest management science》2007,63(2):157-170

The Voluntary Initiative (VI) is a UK programme of measures aimed at reducing the adverse effects of pesticides on the environment. It was initiated in 2001 and will be evaluated during 2006 following a five-year trial period. To assess such a complex scheme, a mixed methodology approach is appropriate, encompassing the assessment of objective deliverables and issues raised by the farming community. A series of focus groups examined the perceptions of the VI by the farming community. Farmer attitudes to the VI appeared to be influenced by the belief that the UK government will, eventually, introduce some form of pesticide tax regardless of the outcome of the VI. Most farmers expressed that they already followed the principles of the VI. It was also evident that the scheme may become more acceptable and better understood as it becomes incorporated into existing farm assurance schemes. This paper proposes a framework for evaluation of the VI that takes into account these perceptions of the VI by the farming community. Based on the analysis of available data, key questions are identified that should be addressed within the final evaluation. These key questions cover the general themes of completion of VI targets and projects, uptake of the VI, environmental impact of the VI and economic implications. To answer the questions, four methods are proposed: a review of literature, a survey of farmers, questions to agencies and environmental modelling.  相似文献   

Serological survey of encephalomyocarditis virus infection in pigs in France   总被引：4，自引：0，他引：4  

Bakkali Kassimi L  Madec F  Guy M  Boutrouille A  Rose N  Cruciere C 《The Veterinary record》2006,159(16):511-514

Samples of serum from 76 gilts, 1440 sows, 1473 piglets and 3093 finishing pigs from 96 farrow-to-finish herds were tested for antibodies to encephalomyocarditis virus (EMCV) in microtitre serum neutralisation tests employing two strains of virus, one associated with myocarditis and the other with reproductive failure. The total seroprevalence of EMCV infection was 2.48 per cent. There was no significant difference between the seroprevalence of the reproductive failure strain (1.6 per cent) and the myocardial strain (1.85 per cent). The seroprevalence was higher in the gilts (6.57 per cent) and sows (5.13 per cent) than in the piglets (1 per cent) and finishing pigs (1.84 per cent), and the highest titres were observed in the sows (1:540) and finishing pigs (1:640). In the gilts, the difference in seroprevalence between the reproductive failure strain (3.95 per cent) and the myocardial strain (5.33 per cent) was wider than in the other groups.  相似文献   

Continental-scale effects of nutrient pollution on stream ecosystem functioning     

Woodward G  Gessner MO  Giller PS  Gulis V  Hladyz S  Lecerf A  Malmqvist B  McKie BG  Tiegs SD  Cariss H  Dobson M  Elosegi A  Ferreira V  Graça MA  Fleituch T  Lacoursière JO  Nistorescu M  Pozo J  Risnoveanu G  Schindler M  Vadineanu A  Vought LB  Chauvet E 《Science (New York, N.Y.)》2012,336(6087):1438-1440

Excessive nutrient loading is a major threat to aquatic ecosystems worldwide that leads to profound changes in aquatic biodiversity and biogeochemical processes. Systematic quantitative assessment of functional ecosystem measures for river networks is, however, lacking, especially at continental scales. Here, we narrow this gap by means of a pan-European field experiment on a fundamental ecosystem process--leaf-litter breakdown--in 100 streams across a greater than 1000-fold nutrient gradient. Dramatically slowed breakdown at both extremes of the gradient indicated strong nutrient limitation in unaffected systems, potential for strong stimulation in moderately altered systems, and inhibition in highly polluted streams. This large-scale response pattern emphasizes the need to complement established structural approaches (such as water chemistry, hydrogeomorphology, and biological diversity metrics) with functional measures (such as litter-breakdown rate, whole-system metabolism, and nutrient spiraling) for assessing ecosystem health.  相似文献   

Breeding without breeding: selection using the genomic best linear unbiased predictor method (GBLUP)   总被引：1，自引：0，他引：1  

Yousry A. El-Kassaby  Jaroslav Kláp?tě  Robert D. Guy 《New Forests》2012,43(5-6):631-637

We demonstrate, using height data from a clonal trial, how the genomic best linear unbiased predictor method (GBLUP) is ideal for determining future breeding potential in situations (either in plantations or wild stands) where high mortality due to biotic or abiotic factors has occurred. The method is effective because it does not require the development of structured pedigree or classical progeny testing, rather it uses DNA fingerprinting to determine the genealogical relationship among individuals. The resulting genetic network is known as the realized relationship matrix, which in turn is used in classical quantitative genetics analyses to determine the genetic worth of all fingerprinted individuals. Selection of desirable individuals among the surviving population is aimed at maximizing genetic diversity even when the original genetic source is unknown. This is accomplished by determining the number of founder genome equivalents which can be used to estimate the inbreeding effective population size. During the selection phase, genetic diversity can be balanced against genetic gain so that diversity is maximized while gain for any particular attribute is optimized.  相似文献   

Apparent prevalence of antibodies to Coxiella burnetii (Q fever) in bulk tank milk from dairy herds in southern Belgium     

Czaplicki G  Houtain JY  Mullender C  Porter SR  Humblet MF  Manteca C  Saegerman C 《Veterinary journal (London, England : 1997)》2012,192(3):529-531

In 2006, a cross-sectional survey was carried out in 206 herds in southern Belgium to estimate the proportion of herds with Q fever-seropositive bulk tank milk (BTM), i.e. herds with an intra-herd seroprevalence >10%. Of the tested herds, 119 (57.8%; 95% CI: 51.1-64.4%) were seropositive. Most had a low antibody titre. Of these herds, 50 were randomly subjected to a real time Coxiella burnetii PCR analysis. The proportion of herds excreting Coxiella in BTM was 30.0% with only 2.0% of herds having a high level of shedding. An additional questionnaire and logistical regression identified some factors which increased the risk of BTM seroconversion (in heifers, drinking water from watercourse or well water) and some which decreased it (in heifers, tie- and free-stalling, and animals of all age in the same shed; in heifers and cows, shed disinfection).  相似文献   

Characterization of the immune response of domestic fowl following immunization with proteins extracted from Dermanyssus gallinae     

David Harrington  Hatem Mohi El Din  Jonathan Guy  Karen Robinson  Olivier Sparagano   《Veterinary parasitology》2009,160(3-4):285-294

Dermanyssus gallinae is the most significant ectoparasite of European poultry egg laying production systems due to high costs of control and associated production losses as well as adverse effects on bird welfare. In this study, soluble proteins were extracted from unfed D. gallinae (DGE) using a urea-based detergent and ultra-filtration, passed through a 0.22 μm filter and blended aseptically with adjuvant. One group of laying hens was immunized with DGE and adjuvant (Montanide ISA 50 V) whilst another group (Control) received physiological saline and adjuvant. All birds were immunized on two occasions, 21 days apart. Antibody response to immunization was determined by ELISA and western blotting using immunoglobulins (Igs) extracted from egg yolk. DGE immunization of hens resulted in a significant (P < 0.05) IgY response compared to controls, although there was no significant difference in IgM response between treatments. A number of proteins were identified by western blotting using IgY antibodies from DGE immunized birds, most prominently at 40 and 230 kDa. Analysis of proteins from approximately corresponding bands on SDS-PAGE confirmed the identity of tropomyosin, whilst other proteins showed high sequence homology with myosin and actin from other arachnid and insect species. Immunization of hens with DGE resulted in a 50.6% increase in mite mortality (P < 0.001) 17 h after feeding when tested by an in vitro mite feeding model. Data in this study demonstrate that somatic antigens from D. gallinae can be used to stimulate a protective immune response in laying hens. Further work is needed to identify other proteins of interest that could confer higher protection against D. gallinae, as well as optimization of the vaccination and in vitro testing protocol.  相似文献