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21.
Pioz M Loison A Gibert P Dubray D Menaut P Le Tallec B Artois M Gilot-Fromont E 《Veterinary microbiology》2007,119(1):19-30
Outbreaks of a previously unrecorded disease have recently affected Pyrenean chamois (Rupicapra pyrenaica pyrenaica) populations across the mountain range. A pestivirus was hypothesized to be the cause of this emerging disease and this type of virus can cross the species barrier and be transmitted to or from wildlife. Using an epidemiological survey conducted from 1995 to 2004 at Orlu, France, we characterized the virus and analyzed its transmission. A phylogenetic analysis of viral sequences and virus neutralization tests showed that the virus belonged to the newly described border disease virus-4 group. The increase of seroprevalence with age indicated that infection can occur at any age and resulted in lifelong immunity. Overall, 70.3% of 323 samples were positive for anti-p80 antibodies and 10.2% of 167 samples showed viremia, as demonstrated by either positive ELISA antigen test or RT-PCR. Infection has thus been widespread in this population since 1995, whereas no mass mortality or clinical signs have been observed. Incidence and seroprevalence varied seasonally and according to number of individuals aged less than 2 years old in the population, so viral transmission was dependent on host population age structure. We propose that the virus is now endemic in this population and is likely detrimental for reproduction and juveniles. Further investigation is needed to estimate the impact of pestivirus on host population dynamics and the risk of cross-transmission to farm animals. 相似文献
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M. Delmas N. Saby D. Arrouays R. Dupas B. Lemercier S. Pellerin C. Gascuel‐Odoux 《Soil Use and Management》2015,31(2):259-269
Total phosphorus (TP) build‐up in agricultural soils represents both a threat to aquatic ecosystems and a valuable resource for future crop production, given the context of increasing food demand combined with the rapid depletion of the world's phosphate reserves. Therefore, it is crucially important (i) to identify the main factors controlling topsoil TP and (ii) to develop methods for mapping its spatial distribution. Multiple linear regression models were used with two distinct approaches to calculate TP and covariates linked to the P cycle. Firstly, covariates were selected from the Réseau de Mesures de la Qualité des Sols database, the French soil monitoring network, which consists of soil samples collected from 2158 sites on a 16‐km regular grid. Secondly, covariates were selected to map TP from spatially exhaustive datasets in France. The first approach explains 80% of variability in topsoil TP. The variables selected are linked to the autochthonous origin of P (parent material), to allochthonous origin (organic carbon and nitrogen contents) and to the retention capacity of soil (Al, Fe, Ca and clay contents). The predicted map obtained from the second approach provides a mean TP of 0.76 g/kg. This study demonstrates that creating national scale maps of TP, based on detailed soil sampling and many variables, is feasible and can be used to model the P cycle and P transfer processes. Such maps can be used in P erosion and transfer models over river basins, and therefore to predict P exports to surface waters. 相似文献
24.
Dambrouck T Marchal R Cilindre C Parmentier M Jeandet P 《Journal of agricultural and food chemistry》2005,53(22):8782-8789
Proteins have proven to play a major role in the stabilization of foam in Champagne wines despite their low concentration that ranges from 4 to 20 mg/L. The aim of this study was to evaluate the effect of fining on total protein and grape invertase contents of champenois base wines and their foaming properties. Data showed that fining and especially the use of bentonite at doses ranging from 10 to 50 g/hL leads to a significant decrease in the total protein content of wines together with that of the grape invertase content, with such a decrease being very detrimental to the foaming properties of the treated wines in terms of foam height (HM) and foam stability (HS). Only a slight decrease in the total protein content, in the grape invertase concentration, and in the foam quality of wines was observed when using casein (10 and 20 g/hL) or bentonite combined with casein (both at 20 g/hL). Our study thus clearly establishes the good correlation existing between the wine protein concentration and its foaming properties. A remarkable correlation was observed between the decrease in the grape invertase content and the total protein content of wines, following bentonite treatments, suggesting that the grape invertase (which represents at least 10-20% of the wine proteins) follows a similar behavior upon fining to other proteins of Champagne wines, despite the high molecular mass and the highly glycosylated structure of this particular protein. Moreover, the decrease in total protein and grape invertase contents of wine after fining with bentonite was found to be correlated with a decrease in the foaming properties of the corresponding wines (with respectively R(2) = 0.89 and 0.95). 相似文献
25.
B.A. Pellerin I.J. Fernandez S.A. Norton J.S. Kahl 《Water, air, and soil pollution》2002,134(1-4):189-204
Near-stream and upslope soil chemical properties were analyzed to infer linkages between soil and surface water chemistry atthe Bear Brook Watershed in Maine [BBWM]. Organic and mineral soil samples were collected along six 20 m transects perpendicular to the stream and one 200 m transect parallel tothe stream. O horizon soils immediately adjacent to the streamhad a significantly higher pH (4.20) and lower soil organic matter percentage (54%) than upslope O horizons (3.84 and 76%,respectively). Additionally, near-stream O horizon soils hadsignificantly higher concentrations of water-soluble Al (2.7 ×),exchangeable Al (2.3 ×), and organically-bound Al (3.9 ×) andsignificantly lower concentrations of exchangeable Ca (0.4 ×) than O horizons upslope. These results suggest that Al can accumulate in non-hydric near-stream zone soils at this site. Mobilization of labile Al from near-stream zone soils duringhydrologic events could play a key role in explaining controls on Al in stream water at BBWM. 相似文献
26.
G Rai-el-Balhaa J L Pellerin G Bodin A Abdullah M Muller 《Veterinary immunology and immunopathology》1987,16(1-2):67-76
This paper describes the effect of the nycthemeral cycle on the lymphocyte response of sheep to different mitogens (PHA, Con A and PWM). A considerable decline in the lymphocyte response was evident in the afternoon and early in the morning in all 6 animals tested. Three peak responses were identified during a 24 hour study period, at 14.00 h, 24.00 h and 08.00 h. The results presented here suggest that this variation in lymphocyte response is a meaningful difference in the response ability of individual lymphocytes. Factors affecting the number of leukocytes and the proportion of different types of lymphocytes in peripheral blood might be the essential causes of variation. To obtain an accurate indication of an individual's immunocompetence, it is important to make a preliminary determination of the optimal hour for sampling. If this is not possible, all the samples must be taken at the same hour on each test day, in order to make significant comparisons. 相似文献
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ABSTRACT: Understanding the spatial dynamics of an infectious disease is critical when attempting to predict where and how fast the disease will spread. We illustrate an approach using a trend-surface analysis (TSA) model combined with a spatial error simultaneous autoregressive model (SARerr model) to estimate the speed of diffusion of bluetongue (BT), an infectious disease of ruminants caused by bluetongue virus (BTV) and transmitted by Culicoides. In a first step to gain further insight into the spatial transmission characteristics of BTV serotype 8, we used 2007-2008 clinical case reports in France and TSA modelling to identify the major directions and speed of disease diffusion. We accounted for spatial autocorrelation by combining TSA with a SARerr model, which led to a trend SARerr model. Overall, BT spread from north-eastern to south-western France. The average trend SARerr-estimated velocity across the country was 5.6 km/day. However, velocities differed between areas and time periods, varying between 2.1 and 9.3 km/day. For more than 83% of the contaminated municipalities, the trend SARerr-estimated velocity was less than 7 km/day. Our study was a first step in describing the diffusion process for BT in France. To our knowledge, it is the first to show that BT spread in France was primarily local and consistent with the active flight of Culicoides and local movements of farm animals. Models such as the trend SARerr models are powerful tools to provide information on direction and speed of disease diffusion when the only data available are date and location of cases. 相似文献
28.
Younes B Cilindre C Villaume S Parmentier M Jeandet P Vasserot Y 《Journal of agricultural and food chemistry》2011,59(11):6239-6246
In this work, Saccharomyces cerevisiae PlR1, a strain isolated from Pinot noir grapes in the Champagne area, was shown to secrete an acid proteolytic activity against bovine serum albumin. This proteolytic activity was detectable in cell-free culture supernatants at the beginning of the exponential growth phase and increased with yeast growth. Using a zymography method, only one protease band with a molecular mass of 72 kDa was observed. This extracellular proteolytic activity was detected in the pH range from 2 to 4 with a maximal value at pH 2.5 and 38 °C and was completely inhibited by pepstatin A. The secretion of this protease did not need any protein inducer and seemed to be insensitive to nitrogen catabolic repression. S. cerevisiae PlR1 was also able to secrete this proteolytic activity during alcoholic fermentation, and it was found to be active against grape proteins, with a molecular mass around 25 kDa, at optimal conditions of 38 °C, pH 3.5. 相似文献
29.
G. Rai-el-Balhaa J. L. Pellerin G. Bodin A. Abdullah H. Hiron 《Comparative immunology, microbiology and infectious diseases》1985,8(3-4):311-318
A new micro-method was used to evaluate in vitro sensitivity of ovine peripheral blood lymphocytes (PBL) to different non specific mitogens (pHA, Con A, PWM) and to investigate the interest of a colorimetric assay for measurement of transformed lymphocytes.
The results showed that sheep PBL in flat-bottomed microplates responded optimally at a cell density of 8 × 106 cells/ml to PHA (2.5 μg/ml), Con A (5 μg/ml) and PWM (5 μg/ml).
The colorimetric assay using a tetrazolium salt (MTT), for measuring the transformed lymphocytes, is very well correlated with the classical method of [3H]thymidine incorporation.
This new revelation technique of the mitogenic response improve the technical value of the assay, which is more rapid and easy-to-read, without diminishing the biological value. 相似文献