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31.
Marta González-Warleta José Antonio Castro-Hermida Javier Regidor-Cerrillo Julio Benavides Gema álvarez-García Miguel Fuertes Luis Miguel Ortega-Mora Mercedes Mezo 《Veterinary research》2014,45(1)
Neospora caninum has been detected only sporadically in cases of ovine abortion, and it has therefore traditionally been considered as an unimportant parasite in small ruminants. This study was carried out with the aim of identifying the pathogen causing serious reproductive problems on a commercial sheep farm. Sera from all rams and ewes tested negative for antibodies against Border disease virus, Schmallenberg virus and Coxiella burnetii, and infections by these agents were therefore ruled out. Nevertheless, seropositivity to N. caninum and/or Toxoplasma gondii was detected, although the seroprevalence was higher in the case of N. caninum. The percentage of lambings and the number of lambs per dam were significantly lower in ewes that were seropositive to N. caninum while no effect on these parameters was detected in ewes that were seropositive to T. gondii. There was also no evidence of infection by T. gondii in the foetal/lamb tissues analyzed by PCR and/or immunohistopathological techniques. On the contrary, the DNA of N. caninum was detected in 13 out of 14 foetuses/lambs descendant from dams seropositive to this parasite. Characteristic lesions caused by N. caninum and/or its antigen were also detected. Genotyping of the N. caninum DNA revealed only two closely related microsatellite multilocus genotypes. The results clearly demonstrate that infection by N. caninum was the cause of the low reproductive performance of this sheep flock. 相似文献
32.
? Context
Pinus pinea L. presents serious problems of natural regeneration in managed forest of Central Spain. The species exhibits specific traits linked to frugivore activity. Therefore, information on plant–animal interactions may be crucial to understand regeneration failure.? Aims
Determining the spatio-temporal pattern of P. pinea seed predation by Apodemus sylvaticus L. and the factors involved. Exploring the importance of A. sylvaticus L. as a disperser of P. pinea. Identifying other frugivores and their seasonal patterns.? Methods
An intensive 24-month seed predation trial was carried out. The probability of seeds escaping predation was modelled through a zero-inflated binomial mixed model. Experiments on seed dispersal by A. sylvaticus were conducted. Cameras were set up to identify other potential frugivores.? Results
Decreasing rodent population in summer and masting enhances seed survival. Seeds were exploited more rapidly nearby parent trees and shelters. A. sylvaticus dispersal activity was found to be scarce. Corvids marginally preyed upon P. pinea seeds.? Conclusions
Survival of P. pinea seeds is climate-controlled through the timing of the dry period together with masting occurrence. Should germination not take place during the survival period, establishment may be limited. A. sylvaticus-mediated dispersal does not modify the seed shadow. Seasonality of corvid activity points to a role of corvids in dispersal. 相似文献33.
34.
Teresa Ostaszewska Konrad Dabrowski Katarzyna Czumiska Wanda Olech & Marta Olejniczak 《Aquaculture Research》2005,36(12):1167-1176
The present study evaluated the performance of two commercial diets: AgloNorse (AN) and BioKyowa (BK), and two experimental, formulated diets based on casein (C) or casein plus casein hydrolysates (CH) in rearing of pike‐perch larvae (Sander lucioperca L.). All fish were 5 day old and control group was fed live Artemia nauplii. Fish were sampled periodically for histological comparison of morphological changes in the digestive tracts. Survival of fish fed Artemia nauplii, BK and AN was similar: 54.4%, 50.8% and 52.4%, respectively, while the fish fed formulated diets C and CH showed considerably lower survival: 28.4% and 21.6% respectively. After 5 weeks of rearing, the average body mass of fish ranged from 212±32 mg in Artemia fed group to 53.8±6.8 mg in C diet fed group. A considerable vacuolization of supranuclear zone in enterocytes of posterior intestine was observed in the larvae fed commercial diets. No anomalies in liver development were found. Hepatocytes of fish fed BK diet showed larger glycogen storage areas, compared with those occupied by lipids. The highest zymogen accumulation of pancreatic cytoplasm was observed in fish fed Artemia. In fish fed C and CH diets, anomalies in digestive system development were indicated by lower and less numerous intestinal folds, smaller hepatocytes, retarded development of gastric glands, and in CH group – also local fatty degeneration of liver. 相似文献
35.
Marta Novo Ana Almodóvar Rosa M. Fernández Mónica Gutiérrez Darío J. Díaz Cosín 《Pedobiologia》2010,53(6):375-379
Endogeic earthworms are difficult study subjects due to the cryptic medium in which they live; thus, only the behaviour of epigeic and anecic earthworms has been studied before. We used microsatellite markers as a tool to elucidate the mate choice processes of Hormogaster elisae, an endogeic earthworm. It was shown to normally mate with two partners, preferably of the same size that are found in close proximity thereby eliminating the need for long-distance dispersion, which could explain the previously observed high genetic differentiation between populations. The genetic analyses of the sperm within each of its four spermathecae showed a uniform distribution with no signs of differential storage of sperm from different partners. 相似文献
36.
Marta I Sabara June E Larence Stacey Halayko 《Journal of veterinary diagnostic investigation》2003,15(5):447-453
The ability of a Japanese quail fibrosarcoma cell line (QT-35) to support the replication of avian metapneumoviruses belonging to the 3 subgroups A (14/1 virus), B (Colorado virus), and C (Hungary virus) enabled the development of assays for the detection and evaluation of virus-specific antibodies. On the basis of the results of enzyme-linked immunosorbent assay (ELISA), plaque reduction neutralization assay (PRNA), immunofluorescent assay (IFA), and Western blot analysis, some degree of antigenic cross-reactivity was observed between prototype viruses belonging to each of the 3 subgroups A, B, and C. The antigen produced in QT-35 cells was found to be superior with respect to its reactivity with virus-specific antibodies, as determined when used in ELISA and IFA. Standardization of both the input virus and the virus-specific antibodies in PRNA enabled a more detailed analysis of the antigenic relationship between these viruses. Specifically, it was observed that 14/1 virus shared more neutralizing regions with Hungary and Colorado viruses than did either of these viruses with 14/1 virus. In addition, Hungary virus shared comparatively fewer neutralizing epitopes with the Colorado virus than did 14/1 virus. Western blot analysis of the reactivity patterns of virus antigen, produced in QT-35 cells, with subgroup-specific antibodies identified a cross-reactive protein migrating at approximately 18 kD. These assays and the information from the Western blot will enable further analysis of avian metapneumovirus isolates to determine antigenic relationships. 相似文献
37.
Pietro P. C. Aucelli Massimo Conforti Marta Della Seta Maurizio Del Monte Lorenzo D'uva Carmen M. Rosskopf Francesca Vergari 《Land Degradation \u0026amp; Development》2016,27(4):1075-1092
This paper focuses on the analysis of the slope and catchment erosion dynamics in a typical Mediterranean context and its sensitivity to recent climatic and socio‐economic changes. The main objective of the present study is to test the reliability of digital photogrammetric analysis to evaluate the time and space evolution of erosion processes mainly triggered by surface running waters and landslides for about the last 60 years. The selected test area is the Landola catchment, a minor tributary of the Upper Orcia River Valley (Southern Tuscany). The Upper Orcia valley is a key site for the comprehension of denudation processes typically acting in Mediterranean badland areas thanks to the following: (i) the availability of long‐lasting erosion monitoring datasets (20 years' long direct measurements at erosion ‘hot spots’); (ii) its representativeness as a sub‐humid Mediterranean badland area; and (iii) the rapidity of development of erosion processes, which makes it suitable as an open‐air laboratory for the study of badland dynamics. The outputs of this work highlight that the application of high‐resolution digital photogrammetric methodologies can represent a powerful and low‐cost tool to evaluate rates and spatial–temporal distribution of denudation processes, as confirmed by the validation through field point monitoring in areas close to the study area. The results obtained for the study area confirm that high erosion rates are a persistent environmental problem for the Upper Orcia Valley, which is not solved up to now, despite various land conservation interventions. The performed multi‐temporal analysis shows a slight decrease in the average water erosion rate during the last 60 years and a parallel increase in the frequency of mass wasting events. These variations are most likely related to a complex interplay between land use changes that have affected the study area during the studied period, revealing a very delicate equilibrium between farming activities and erosion processes. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
38.
The 541 × Ot1-3 intercross population and bulked segregant analysis (BSA) were used to search for molecular markers linked to genes underlying sprouting and alpha-amylase activity. Six RAPD markers showing association with studied traits were tested for their potential effectiveness in selecting sprouting resistant genotypes. It was shown that although individual effects of markers were not high, their accumulation in one genotype gives substantial increase in sprouting resistance. 相似文献
39.
如今,在这个全球伴随着激烈竞争的市场环境下,非洲及亚洲的花卉从业者成为国际上花卉栽培大军中的一支新兴队伍,并且这支队伍的力量正在与日俱增, 相似文献
40.
There were two objectives in the study: 1) To determine exchangeable K and non-exchangeable K in soils with different potassium depletion levels and mineralogy as plant sources 2) To establish a relationship between the mineralogy vs exchangeable K (Ke) and non-exchangeable K (Kne) mobilization. An extraction experiment of soils was carried out in a greenhouse, with a total of 6 consecutive crops of ryegrass. Different supply rates for plant K were determined by Ke and Kne mobilization according to the soil intensity of use. The contribution of the Ke was greater and generated higher amount of K uptake during maximum availability period (from 0 to the 1st harvest) than in the later period when soil K was already depleted. For this the initial exchangeable K and the illite concentration of soils accounted for almost 100% (R2 = 0.981 P=0.01) of the K taken up by ryegrass. For the following period (from the 2nd harvest to the 6th), Kne forms became more important. Plant K supply was not only a result of initial exchangeable K and illite concentration but presumably also of primary K-bearing minerals. 相似文献