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71.
Salmonella enterica causes a variety of diseases, including gastroenteritis and typhoid fever. The success of this pathogen depends on its capacity to proliferate within host cells in a membrane-bound compartment. We found that the Salmonella-containing vacuole recruited the plus-end-directed motor kinesin. Bacterial effector proteins translocated into the host cell by a type III secretion system antagonistically regulated this event. Among these effectors, SifA targeted SKIP, a host protein that down-regulated the recruitment of kinesin on the bacterial vacuole and, in turn, controlled vacuolar membrane dynamics. 相似文献
72.
Marc Girondot Philippe Rivalan Ronald Wongsopawiro Jean-Paul Briane Vincent Hulin Stéphane Caut Elodie Guirlet Matthew H Godfrey 《BMC ecology》2006,6(1):11-12
Background
Marine turtles deposit their eggs on tropical or subtropical beaches during discrete nesting seasons that span several months. The number and distribution of nests laid during a nesting season provide vital information on various aspects of marine turtle ecology and conservation. 相似文献73.
Bernard Davoust Oleg Mediannikov Jeanne Chene Raphaël Massot Raphaël Tine Mamadou Diarra Jean-Paul Demoncheaux Pierre Scandola Frédéric Beugnet Luc Chabanne 《Comparative immunology, microbiology and infectious diseases》2013
In Dakar kennels where morbidity and mortality attributed to diseases transmitted by ticks were high, we conducted a field study to assess the prevalence of Ehrlichia canis, Anaplasma platys and Babesia spp. infections in two kennels (n = 34 dogs) and to study the impact of tick protection. The first day of the study, the E. canis PCR were positive in 18 dogs (53%). A. platys was found in one dog and all dogs were negative for Babesia spp. After one month of doxycycline treatment, the number of PCR positive dogs decreased significantly to 2 (5.9%). During seven months, all dogs were treated monthly topically with a novel combination (Certifect®, Merial) delivering at least 6.7 mg fipronil/kg body weight, 8.0 mg amitraz/kg and 6 mg (S)-methoprene/kg. The number of PCR positive dogs remained stable all over the seven months, with 4 dogs being positive at Day 90 and 2 at Day 210. The combination of treatment and monthly prevention had a significant effect in the two kennels. All dogs remained healthy, which was not the case in previous years. 相似文献
74.
Jean-Paul Sampoux Pierre BaudouinBernard Bayle Vincent BéguierPierre Bourdon Jean-François ChossonFrançois Deneufbourg Christophe GalbrunMarc Ghesquière Dominique NoëlWieslaw Pietraszek Bernard TharelAnne Viguié 《Field Crops Research》2011,123(2):117-129
Breeding to improve perennial grasses for forage usage aims to increase the whole-plant aerial biomass. However, the ability to increase the whole-plant yield by breeding may be questionable in grasses which are expected to reach an optimal leaf area index during grass stand growth rather rapidly. We carried out a field experiment aiming to compare herbage yield and other performances of seven natural populations and 21 cultivars of diploid perennial ryegrass registered on European National lists in the last 40 years. Cultivars were sampled in the spike emergence earliness range used for pasture usage, i.e. in the semi-late and late earliness range according to the French classification into spike emergence earliness groups. Forage performances of populations and cultivars were tested in four locations in monthly cut dense sward plots. Morphological and phenological traits were recorded in two spaced-plant experiments, and seed yield was assessed in two locations in standard seed production conditions. Trait regression on cultivar registration year pointed out that total dry-matter yield of cultivars increased by +3.2% per decade. However, dry-matter yield was not improved in the most favourable period for grass growth, i.e. in spring. On the other hand, it was improved in summer (+2.8% per decade) and autumn (+7.4% per decade) when the aerial biomass production is on average rather small. Breeders succeeded in significantly reducing aftermath heading. Reduction in aftermath heading is likely to have contributed to the noted increase in summer and autumn dry-matter yields, and to a moderate improvement in herbage feeding value. Breeding was also efficient in improving rust resistance and in bringing forward the start of spring growth. For monthly cut swards, we evidenced a clear association of leaf and lamina lengths with spring and summer dry-matter yields. Breeding for long leaves, or for high leaf elongation rate, should contribute to improve the cumulated intercepted radiation during re-growths, and consequently could be a way of improving the spring dry-matter yield. Seed yield did not improve with breeding for forage performances. However, we did not notice any negative association between the seed yield and traits related with forage usage. Direct selection pressures on seed yield criteria applied at the core of the breeding process should enable to improve the seed yield without any negative impact on forage performances. 相似文献
75.
Wood production represents a large but variable fraction of gross primary production (GPP) in highly productive Eucalyptus plantations. Assessing patterns of carbon (C) partitioning (C flux as a fraction of GPP) between above- and belowground components is essential to understand mechanisms driving the C budget of these plantations. Better knowledge of fluxes and partitioning to woody and non-woody tissues in response to site characteristics and resource availability could provide opportunities to increase forest productivity. Our study aimed at investigating how C allocation varied within one apparently homogeneous 90 ha stand of Eucalyptus grandis (W. Hill ex Maiden) in Southeastern Brazil. We assessed annual above-ground net primary production (ANPP: stem, leaf, and branch production) and total belowground C flux (TBCF: the sum of root production and respiration and mycorrhizal production and respiration), GPP (computed as the sum of ANPP, TBCF and estimated aboveground respiration) on 12 plots representing the gradient of productivity found within the stand. The spatial heterogeneity of topography and associated soil attributes across the stand likely explained this fertility gradient. Component fluxes of GPP and C partitioning were found to vary among plots. Stem NPP ranged from 554 g C m(-2) year(-1) on the plot with lowest GPP to 923 g C m(-2) year(-1) on the plot with highest GPP. Total belowground carbon flux ranged from 497 to 1235 g C m(-2) year(-1) and showed no relationship with ANPP or GPP. Carbon partitioning to stem NPP increased from 0.19 to 0.23, showing a positive trend of increase with GPP (R(2) = 0.29, P = 0.07). Variations in stem wood production across the gradient of productivity observed at our experimental site were a result of the variability in C partitioning to different forest system components. 相似文献
76.
Merhej V Cammilleri S Piquet P Casalta JP Raoult D 《Comparative immunology, microbiology and infectious diseases》2012,35(1):45-49
Coxiella burnetii, the causative agent of Q fever, may cause culture-negative vascular graft infections that can be diagnosed by serology and molecular biology. We present a case of vascular graft infection detected by positron emission tomography (PET) scanner. The presence of C. burnetii was confirmed by high antibody titers and positive polymerase chain reaction specific for C. burnetii. This report emphasizes the relevance of the PET scanner in the diagnosis of infection when used in association with Q fever serology and molecular biology for the etiological identification of C. burnetii. 相似文献
77.
13C and 15N isotopic fractionation in trees, soils and fungi in a natural forest stand and a Norway spruce plantation 总被引:1,自引:0,他引:1
Bernd Zeller Claude Brechet Jean-Paul Maurice François Le Tacon 《Annals of Forest Science》2007,64(4):419-429
15N and 13C natural abundances of foliage, branches, trunks, litter, soil, fungal sporophores, mycorrhizas and mycelium were determined in two forest stands, a natural forest and a Norway spruce plantation, to obtain some insights into the role of the functional diversity of saprotrophic and ectomycorrhizal fungi in carbon and nitrogen cycles. Almost all saprotrophic fungi sporophores were enriched in 13C relative to their substrate. In contrast, they exhibited no or very little shift of δ15N. Judging from the amount of C discrimination, ectomycorrhizal fungi seem to acquire carbon from their host or from dead organic matter. Some ectomycorrhizal species seem able to acquire nitrogen from dead organic matter and could be able to transfer it to their host without nitrogen fractionation, while others supply their host with 15N-depleted nitrogen. Moreover ectomycorrhizal species displayed a significant N fractionation during sporophore differentiation, while saprotrophic fungi did not. 相似文献
78.
Atkins CE Keene BW Brown WA Coats JR Crawford MA DeFrancesco TC Edwards NJ Fox PR Lehmkuhl LB Luethy MW Meurs KM Petrie JP Pipers FS Rosenthal SL Sidley JA Straus JH 《Journal of the American Veterinary Medical Association》2007,231(7):1061-1069
OBJECTIVE: To determine the efficacy of long-term enalapril administration in delaying the onset of congestive heart failure (CHF). DESIGN: Placebo-controlled, double-blind, multicenter, randomized trial. ANIMALS: 124 dogs with compensated mitral valve regurgitation (MR). PROCEDURES: Dogs randomly assigned to receive enalapril or placebo were monitored for the primary endpoint of onset of CHF for < or = 58 months. Secondary endpoints included time from study entry to the combined endpoint of CHF-all-cause death; number of dogs free of CHF at 500, 1,000, and 1,500 days; and mean number of CHF-free days. RESULTS: Kaplan-Meier estimates of the effect of enalapril on the primary endpoint did not reveal a significant treatment benefit. Chronic enalapril administration did have a significant benefit on the combined endpoint of CHF-all-cause death (benefit was 317 days [10.6 months]). Dogs receiving enalapril remained free of CHF for a significantly longer time than those receiving placebo and were significantly more likely to be free of CHF at day 500 and at study end. CONCLUSIONS AND CLINICAL RELEVANCE: Chronic enalapril treatment of dogs with naturally occurring, moderate to severe MR significantly delayed onset of CHF, compared with placebo, on the basis of number of CHF-free days, number of dogs free of CHF at days 500 and study end, and increased time to a combined secondary endpoint of CHF-all-cause death. Improvement in the primary endpoint, CHF-free survival, was not significant. Results suggest that enalapril modestly delays the onset of CHF in dogs with moderate to severe MR. 相似文献
79.
Emmanuelle Roque d’Orbcastel Jeanine Person-Le Ruyet Nicolas Le Bayon Jean-Paul Blancheton 《Aquacultural Engineering》2009,40(2):79-86
The objective of this study was to compare fish performance and welfare at different stocking densities in a recirculating system (RS) and a flow through system (FTS) under field conditions. During the 77 days experiment, the fish survival rate was high (99.3%) and stocking density increased from 57 to 98–108 kg m?3. No significant differences in growth were observed between RS and FTS until day 56. Later, growth decreased in the FTS, while it remained similar to the farm reference at 50 kg m?3 in the RS. Final weight was 17% higher in RS than in FTS. The maximum carrying capacity of the RS was near 100 kg m?3, limited by NO2 increase up to safe level at the end of the experiment, the maximum carrying capacity of the FTS was near 85 kg m?3, probably limited by CO2 concentration (17.8 ± 5.7 mg l?1). In the RS, the relative length index of pectoral and dorsal fins was lower than in the FTS, which may be attributed to the tank hydrodynamics. In both systems, an improvement of the pectoral and dorsal profile was observed at the end of the experiment, attributed to a swimming activity reduction that may have decreased contact between individuals. In the RS, high caudal fin deterioration (50% versus 20% in FTS) was observed irrespective of stocking density, that could be linked to the highest water velocity modifying the fish swimming activity. The results confirm that when water quality is maintained in safe level ranges, high densities can be used in trout RS without fish performance and pectoral or dorsal fin deterioration, but with a major caudal impairment. 相似文献
80.
Towards environmentally sustainable aquaculture: Comparison between two trout farming systems using Life Cycle Assessment 总被引:2,自引:1,他引:1
Emmanuelle Roque dOrbcastel Jean-Paul Blancheton Joël Aubin 《Aquacultural Engineering》2009,40(3):113-119
Life Cycle Assessment (LCA) was applied to evaluate the global environmental impact of two scenarios of trout production systems based on the operational information from an operational farm using a flow through system (FTF) and an experimental pilot low head recirculating system (RSF) located on the same site. The main differences between the environmental balances of the two systems were relative to water use, eutrophication potential and energy use. Independently of the system used, feed is the key indicator in determining the environmental balance (notwithstanding eutrophication potential and water dependence) monitored by fish production, chemical products, buildings and energy consumption.Consequently, when considering the RSF with a lower feed conversion ratio (0.8 versus 1.1 for FTF), the environmental balance of the RSF is more favourable at both global and regional levels, except with regards to energy use. RSF water dependence is 93% lower than the FTF and its eutrophication potential is 26–38% lower due to reduced waste release. On the other hand, at 57,659 MJ per ton of fish produced (16 kWh per kg), the RSF consumes 24–40% more energy than the FTF, especially for aeration and water treatment. Nevertheless, the RSF has significant potential for energy reduction through improvements to airlift and biofilter designs which would reduce RSF energy use to a level similar to that of the FTF (34,869–43,841 MJ per ton of fish produced, corresponding to 10 and 12 kWh respectively). LCA is therefore a powerful tool which can be used on fish farms to define and prioritise the most promising potential improvements to the system. 相似文献