Eucalyptus occidentalis plantlets are naturally infected by pathogenic Agrobacterium tumefaciens     

Zoulikha Krimi  Aïda Raio  Annik Petit  Xavier Nesme  Yves Dessaux 《European journal of plant pathology / European Foundation for Plant Pathology》2006,116(3):237-246

In the Sidi M’djahed nursery (Algeria), over 60,000 eucalyptus (Eucalyptus occidentalis) plantlets exhibited tumour-like growths localized at the crown of the plants that resembled crown galls caused by Agrobacterium tumefaciens. Bacteria colonizing the galls were isolated and purified. Most (22 out of 24) of the isolates had cultural and biochemical characteristics similar to those of strains of the biovar 1 of A. tumefaciens. Twenty out of 22 Agrobacterium isolates induced tumour formation on various test plants. In PCR experiments, DNA extracted from these virulent strains yielded an amplification signal corresponding to a 247-bp fragment located within the virulence region of nopaline type Ti plasmid. Consistent with this, the opine nopaline was detected in the tumours induced on test plants – but not on eucalyptus plants. Nopaline was degraded by the 20 pathogenic isolates that were also sensitive to agrocin 84, indicating the presence of a nopaline-type pTi in these strains. The chromosomal region encoding the 16S rRNA was analyzed in a sub-population of the pathogenic agrobacterial isolates. The analyzed strains were found to belong to the ribogroup of the reference strain B6. Interestingly, Eucalyptus camaldulensis and Eucalyptus cladocalyx grown in the same nursery and in the same soil substrate developed no galls.  相似文献   

From Hiking Through Farmland to Farming in a Leisure Landscape: Changing Social Perceptions of the European Landscape     

Arjen E. Buijs  Bas Pedroli  Yves Luginbühl 《Landscape Ecology》2006,21(3):375-389

The idea that landscape has been created by human activities on a biophysical basis allows for clear cause–effect reasoning. However, landscape planning and management practice learns that it is impossible to neglect the social perception of landscape, i.e. the ways people think about nature and landscape. It is the result of social research and human sciences of the last decade that a differentiation in views of nature and landscape can be identified in the different groups of social actors in the landscape. Case studies from France and the Netherlands show a marked change in values attributed to nature and landscape in the end of the last century. Social demand for landscape is growing and a shift from a functional image of nature and landscape to a more hedonistic image like the Arcadian and wilderness images has taken place. Comparing the Netherlands with France and rural with urban inhabitants, the influence of urbanisation is evident in this process. It is further shown that images of nature vary considerably between for example farmers, urban residents, hunters and conservationists. The way people perceive landscape seems determined by their functional ties with the landscape and the social praxis in which they encounter the landscape. It is concluded that the concept of landscape is nearer to the lifeworld of people than the abstract notions of nature and biodiversity. This implies a big challenge both for national and international landscape policies and for local landscape management initiatives to be developed, taking into due consideration both the material and immaterial nature of landscape.  相似文献   

Comparison of efficacy and safety of paste formulations of firocoxib and phenylbutazone in horses with naturally occurring osteoarthritis   总被引：1，自引：0，他引：1  

Doucet MY  Bertone AL  Hendrickson D  Hughes F  Macallister C  McClure S  Reinemeyer C  Rossier Y  Sifferman R  Vrins AA  White G  Kunkle B  Alva R  Romano D  Hanson PD 《Journal of the American Veterinary Medical Association》2008,232(1):91-97

OBJECTIVE: To compare efficacy and safety of paste formulations of firocoxib and phenylbutazone in horses with naturally occurring osteoarthritis. DESIGN: Randomized controlled clinical trial. ANIMALS: 253 client-owned horses with naturally occurring osteoarthritis. PROCEDURES: Horses were treated with firocoxib (0.1 mg/kg [0.045 mg/lb], PO, q 24 h) or phenylbutazone (4.4 mg/kg [2 mg/lb], PO, q 24 h) for 14 days. Physical examinations and lameness evaluations were performed prior to treatment and after 7 and 14 days. Clinical improvement was defined as a reduction of at least 1 lameness grade or a combined reduction of at least 3 points in scores for pain during manipulation or palpation, joint swelling, joint circumference, and range of motion. RESULTS: Proportion of horses clinically improved on day 14 for the firocoxib group (104/123 [84.6%]) was not significantly different from the proportion for the phenylbutazone group (103/119 [86.6%]). Proportion of horses that were improved on day 14 was significantly greater for horses treated with firocoxib than for horses treated with phenylbutazone with regard to score for pain on manipulation or palpation (P = 0.028), joint circumference score (P = 0.026), and range of motion score (P = 0.012), but not for overall lameness score or joint swelling score. No direct treatment-related adverse effects were detected during the study. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggested that overall clinical efficacy of a paste formulation of firocoxib in horses with naturally occurring osteoarthritis was comparable to efficacy of a paste formulation of phenylbutazone.  相似文献   

Orientation of bovine CTL responses towards PIM, an antibody-inducing surface molecule of Theileria parva, by DNA subunit immunization     

Ververken C  Geysen D  Loots K  Janssens ME  Guisez Y  Goddeeris BM 《Veterinary immunology and immunopathology》2008,124(3-4):253-263

East Coast fever, an acute lymphoproliferative disease of cattle, is caused by the apicomplexan parasite Theileria parva. Protective immunity is mediated by CD8(+) cytotoxic T lymphocytes directed against schizont-infected cells. The polymorphic immunodominant molecule, although an antibody-inducing surface molecule of the schizont, has been hypothesized to play a role in protective immunity. In order to evaluate the immunogenicity of PIM for inducing CTL, cattle were immunized with PIM in isolation from other T. parva antigens, forcing the presentation of PIM-derived epitopes on the MHC class I molecules. Although parasite-specific cytotoxicity was induced in both vaccinated animals, their immune response was clearly different. One animal generated MHC-restricted parasite-specific CTL against PIM while the other calf exhibited a strong PIM-specific proliferative response but non-MHC-restricted parasite-specific cytotoxicity. Only calf 1 survived a lethal sporozoite challenge. This DNA immunization technique with an antigen in isolation of CTL-immunodominant antigens might open possibilities for directing CTL responses against predefined antigens, such as strain cross-reacting CTL antigens.  相似文献   

Increases in heat-induced tree mortality could drive reductions of biomass resources in Canada’s managed boreal forest     

Chaste  Emeline  Girardin  Martin P.  Kaplan  Jed O.  Bergeron  Yves  Hély  Christelle 《Landscape Ecology》2019,34(2):403-426

Landscape Ecology - The Canadian boreal forest provides valuable ecosystem services that are regionally and globally significant. Despite its importance, the future of the Canadian boreal forest is...  相似文献   

Factors influencing fallback by adult Atlantic salmon following transport into a novel river reach     

Danielle M. Frechette  Elsa Goerig  Normand E. Bergeron 《Fisheries Management and Ecology》2020,27(1):20-31

Transport of salmonids allows upstream migrating adults to bypass barriers to migration, for example hydroelectric dams or adverse habitats. Downstream movement (“fallback”) after transport is common and removes individuals from spawning populations, with possible detrimental consequences for population productivity. Time‐to‐event analysis was used to determine effects of fish characteristics, transport conditions and environmental variables on fallback by adult Atlantic salmon transported to an inaccessible river reach as a population enhancement strategy on the Rivière Sainte‐Marguerite Nord‐Est (Québec, Canada). Of 68 salmon transported, 19 exhibited post‐transport fallback within seven days of transport. Fork length (FL) was the only factor that increased risk of post‐transport fallback; there was a 5% increase in the proportion of large salmon (≥780 mm FL) exhibiting post‐transport fallback relative to individuals of median size (750 mm FL). Although the present study was limited by small sample size, the findings will help inform design of transport programmes in freshwater systems.  相似文献   

Minimizing phosphorus discharge from aquaculture earth ponds by a novel sediment retention system   总被引：1，自引：0，他引：1  

Philippe Lefranois  Jaume Puigagut  Florent Chazarenc  Yves Comeau 《Aquacultural Engineering》2010,43(3):94-100

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Reduced cadherin expression associated with resistance to Bt toxin Cry1Ac in pink bollworm     

Jeffrey A Fabrick  Lolita G Mathew  Dannialle M LeRoy  J Joe Hull  Gopalan C Unnithan  Alex J Yelich  Yves Carrire  Xianchun Li  Bruce E Tabashnik 《Pest management science》2020,76(1):67-74

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3D fluorescent in situ hybridization using Arabidopsis leaf cryosections and isolated nuclei     

Leïla Tirichine  Philippe Andrey  Eric Biot  Yves Maurin  Valérie Gaudin 《Plant methods》2009,5(1):11-7

Background  

Fluorescent hybridization techniques are widely used to study the functional organization of different compartments within the mammalian nucleus. However, few examples of such studies are known in the plant kingdom. Indeed, preservation of nuclei 3D structure, which is required for nuclear organization studies, is difficult to fulfill.  相似文献   

Osmotic adaptation of Oncorhynchus kisutch Walbaum     

Gilles Boeuf  Pierre Lasserre  Yves Harache 《Aquaculture (Amsterdam, Netherlands)》1978,15(1):35-52

Coho salmon yearlings, reared in France in a freshwater hatchery, were directly transferred to sea water at three different periods of the year: 14 January, 3 March and 14 April 1976. The last two experiments were realized at three different salinities: 25, 30 and 35‰.The results show important seasonal differences in the osmoregulatory responses. The direct transfer to 35‰ reveals some osmoregulatory problems which are not discernable at lower salinities. Yearlings transferred to a 35‰ sea water present a much higher and faster rise of plasma electrolytes and of branchial Na⁺K⁺ ATPase activity than fish transferred to a 25 or 30‰ sea water.It was found that a physiologically pre-adapted fish, characterized by a high level of branchial Na⁺K⁺ ATPase activity in fresh water (April) will present in sea water a slower and more regular increase in gill Na⁺K⁺ ATPase activity than fish with a low level of enzyme activity in fresh water (January–March). These smolts transferred to 25 and 30‰ sea water in April do not exhibit important variations, whereas a well-marked osmotic disequilibrium appears at 35‰. However, this osmotic stress is much more rapidly controlled than in the previous transfers.Our results suggest that the highest tolerance to sea water is reached only at time of smolting and that the time of transfer may have a direct influence on the intensity of the osmotic stress. These facts might be of considerable importance for the development of marine rearing of coho salmon in coastal areas where the salinities stay usually above 30‰ which constitutes an unusual environment for the species under consideration.  相似文献