Hepatitis E virus infection dynamics and organic distribution in naturally infected pigs in a farrow-to-finish farm   总被引：1，自引：0，他引：1  

de Deus N  Casas M  Peralta B  Nofrarías M  Pina S  Martín M  Segalés J 《Veterinary microbiology》2008,132(1-2):19-28

The objective of the present study was to determine the pattern of Hepatitis E virus (HEV) infection in a naturally infected, farrow-to-finish herd. For that purpose, a prospective study was conducted in randomly selected 19 sows and 45 piglets. Blood samples were collected from sows at 1 week post-farrowing and from piglets at 1, 3, 6, 9, 12, 15, 18 and 22 weeks of age. Furthermore 3 or 5 animals were necropsied at each bleeding day (but at 1 week of age), and serum, bile, liver, mesenteric lymph nodes and faeces taken. HEV IgG, IgM and IgA antibodies were determined in serum and viral RNA was analysed in all collected samples by semi-nested RT-PCR. Histopathological examination of mesenteric lymph nodes and liver was also conducted. From 13 analysed sows, 10 (76.9%) were positive to IgG, one to IgA (7.7%) and two to IgM (15.4%) antibodies specific to HEV. In piglets, IgG and IgA maternal antibodies lasted until 9 and 3 weeks of age, respectively. IgG seroconversion occurred by 15 weeks of age while IgM and IgA at 12. On individual basis, IgG was detectable until the end of the study while IgM and IgA antibody duration was of 4-7 weeks. HEV RNA was detected in serum at all analysed ages with the highest prevalence at 15 weeks of age. HEV was detected in faeces and lymph nodes for the first time at 9 weeks of age and peaked at 12 and 15 weeks of age. This peak coincided with the occurrence of hepatitis as well as with HEV detection in bile, liver, mesenteric lymph nodes and faeces, and also with highest IgG and IgM OD values at 15 weeks. Finally, different HEV sequences from this farm were obtained, which they clustered within 3 different groups, together with other Spanish sequences, all of them of genotype 3. Moreover, the present study also indicates that the same pig can be infected with at least two different strains of HEV during its productive life. This is the first study characterizing HEV infection in naturally infected pigs with chronological virus detection and its relationship with tissue lesions throughout the productive life of the animals.  相似文献   

Report of the 3rd Havemeyer workshop on allergic diseases of the Horse, Hólar, Iceland, June 2007     

Marti E  Gerber V  Wilson AD  Lavoie JP  Horohov D  Crameri R  Lunn DP  Antczak D  Björnsdóttir S  Björnsdóttir TS  Cunningham F  Dérer M  Frey R  Hamza E  Horin P  Heimann M  Kolm-Stark G  Olafsdóttir G  Ramery E  Russell C  Schaffartzik A  Svansson V  Torsteinsdóttir S  Wagner B 《Veterinary immunology and immunopathology》2008,126(3-4):351-361

Allergic diseases occur in most mammals, although some species such as humans, dogs and horses seem to be more prone to develop allergies than others. In horses, insect bite hypersensitivity (IBH), an allergic dermatitis caused by bites of midges, and recurrent airway obstruction (RAO), a hyperreactivity to stable born dust and allergens, are the two most prevalent allergic diseases. Allergic diseases involve the interaction of three major factors: (i) genetic constitution, (ii) exposure to allergens, and (iii) a dysregulation of the immune response determined by (i) and (ii). However, other environmental factors such as infectious diseases, contact with endotoxin and degree of infestation with endoparasites have been shown to influence the prevalence of allergic diseases in humans. How these factors may impact upon allergic disease in the horse is unknown at this time. The 3rd workshop on Allergic Diseases of the Horse, with major sponsorship from the Havemeyer Foundation, was held in Hólar, Iceland, in June 2007 and focussed on immunological and genetic aspects of IBH and RAO. This particular venue was chosen because of the prevalence of IBH in exported Icelandic horses. The incidence of IBH is significantly different between Icelandic horses born in Europe or North America and those born in Iceland and exported as adults. Although the genetic factors and allergens are the same, exported adult horses show a greater incidence of IBH. This suggests that environmental or epigenetic factors may contribute to this response. This report summarizes the present state of knowledge and summarizes important issues discussed at the workshop.  相似文献   

Characterization of fluoroquinolone resistance in Escherichia coli strains from ruminants.     

Sonia Jurado  José A Orden  Pilar Horcajo  Ricardo De La Fuente  José A Ruiz-Santa-Quiteria  Susana Martínez-Pulgarín  Gustavo Domínguez-Bernal 《Journal of veterinary diagnostic investigation》2008,20(3):342-345

Thirty-seven fluoroquinolone-resistant Escherichia coli strains from ruminants (according to Clinical and Laboratory Standards Institute guidelines) were screened by molecular methods for mutations in the quinolone resistance-determining region (QRDR) of the gyrA and parC genes and for the presence of the qnrA gene. One of the strains studied was an enterohemorrhagic E. coli (EHEC) strain potentially pathogenic for humans. Three E. coli strains resistant to enrofloxacin (minimal inhibitory concentration [MIC] = 2 microg/ml) but not to ciprofloxacin (MIC = 1 microg/ml) presented single mutations in the gyrA and parC genes, while 34 strains resistant to both fluoroquinolones presented double and single mutations in gyrA and parC, respectively (31 strains), or double mutations in gyrA and parC (3 strains). The EHEC strain presented a double amino acid substitution in the GyrA protein (Ser-83-->Leu and Asp-87-->Gly) and a double amino acid substitution in the ParC protein (Gly-78-->Cys and Ser-80-->Arg), one of which has not been previously described. The present study shows that most of the mutations in the QRDR of the gyrA and parC genes of fluoroquinolone-resistant E. coli strains from ruminants are the same as those seen in E. coli strains from other animal species and humans and that there are no differences in mutation patterns in the QRDR of E. coli strains from healthy ruminants and those with diarrhea. No strains carried qnrA, which indicates that this gene does not play an important role in the selection of fluoroquinolone-resistant E. coli strains from ruminants.  相似文献   

Transmission Efficiency of <Emphasis Type="Italic">Potato Leafroll Virus</Emphasis> by Four Potato Colonizing Aphid Species in Tunisian Potato Fields     

Wafa Khaled  Ibtissem Ben Fekih  Sabrine Nahdi  Rebha Souissi  Sonia Boukhris-Bouhachem 《Potato Research》2018,61(1):89-96

This study investigated the transmission efficiency of Potato leafroll virus (PLRV) by four potato colonizing aphid species, Myzus persicae, Macrosiphum euphorbiae, Aphis gossypii and Aphis fabae, reported from leaves and yellow water trap. Physalis floridana was used as a test plant for virus transmission. DAS-ELISA was used for virus screening of samples as well as virus detection on the test plant after transmission experiment. A 2-h period was sufficient for the tested aphids to acquire PLRV virions. However, a difference in the transmission potential occurred according to the aphid species. The highest potential was recorded for M. persicae and M. euphorbiae, at 90 and 80%, respectively. For the first time, the study revealed the PLRV transmission efficiency of A. fabae, estimated at 50%. The lowest potential rate of 30% was recorded for A. gossypii. This study highlights the PLRV transmission capacities of four potato colonizing aphids suspected to play a key role in the spread of PLRV in potato seed production sites.  相似文献   

Controlling Properties and Cytotoxicity of Chitosan Nanocapsules by Chemical Grafting     

Laura De Matteis  Maria Alleva  Inés Serrano-Sevilla  Sonia García-Embid  Grazyna Stepien  María Moros  Jesús M. de la Fuente 《Marine drugs》2016,14(10)

The tunability of the properties of chitosan-based carriers opens new ways for the application of drugs with low water-stability or high adverse effects. In this work, the combination of a nanoemulsion with a chitosan hydrogel coating and the following poly (ethylene glycol) (PEG) grafting is proven to be a promising strategy to obtain a flexible and versatile nanocarrier with an improved stability. Thanks to chitosan amino groups, a new easy and reproducible method to obtain nanocapsule grafting with PEG has been developed in this work, allowing a very good control and tunability of the properties of nanocapsule surface. Two different PEG densities of coverage are studied and the nanocapsule systems obtained are characterized at all steps of the optimization in terms of diameter, Z potential and surface charge (amino group analysis). Results obtained are compatible with a conformation of PEG molecules laying adsorbed on nanoparticle surface after covalent linking through their amino terminal moiety. An improvement in nanocapsule stability in physiological medium is observed with the highest PEG coverage density obtained. Cytotoxicity tests also demonstrate that grafting with PEG is an effective strategy to modulate the cytotoxicity of developed nanocapsules. Such results indicate the suitability of chitosan as protective coating for future studies oriented toward drug delivery.  相似文献   

Interacting effects of soil degradation and precipitation on plant productivity in NE Patagonia,Argentina     

María Victoria Campanella  César Mario Rostagno  Lina Sonia Videla  Alejandro Jorge Bisigato 《Arid Land Research and Management》2016,30(1):79-88

Our objective was to examine the effects of inter-annual variation of precipitation on productivity of two dominant species (Chuquiraga avellanedae, an evergreen shrub, and Nassella tenuis, a perennial grass) in two communities of contrasting soil degradation: a herbaceous steppe with shrubs (HSS) and a degraded shrub steppe (SS). Data were collected during two consecutive years with different annual precipitation. Aboveground productivity was determined nondestructively using a double sampling approach. The number of inflorescences per plant was recorded too. Perennial grass productivity was lower in SS than in HSS in both years, while shrub productivity was lower in SS only during the year of below average precipitation. With rising precipitation the perennial grass increased the number of inflorescences while the evergreen shrub augmented vegetative biomass. In summary, the effects of precipitation on plant productivity are community dependent; abiotic factors, such as superficial and sub-superficial soil characteristics, and biotic factors, such as leaf area index (LAI) or tussock sizes, may interact to influence the responses of species to precipitation. Our results suggest that if precipitation increased, this would favor the dominance of shrubs over grasses.  相似文献   

Characterization of the structure,dynamics, and productivity of mixed-species stands: review and perspectives     

Miren del Río  Hans Pretzsch  Iciar Alberdi  Kamil Bielak  Felipe Bravo  Andreas Brunner  Sonia Condés  Mark J. Ducey  Teresa Fonseca  Nikolas von Lüpke  Maciej Pach  Sanja Peric  Thomas Perot  Zahera Souidi  Peter Spathelf  Hubert Sterba  Martina Tijardovic  Margarida Tomé  Patrick Vallet  Andrés Bravo-Oviedo 《European Journal of Forest Research》2016,135(1):23-49

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Responses of photosynthetic parameters to differences in winter temperatures throughout a temperature gradient in two evergreen tree species     

Sonia Mediavilla  Patricia González-Zurdo  Josefa Babiano  Alfonso Escudero 《European Journal of Forest Research》2016,135(5):871-883

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Methods for Cercospora coffeicola protoplast isolation and genetic transformation with the green fluorescent protein     

André Gomes Coelho Souza  Sonia Herrero  Luiz Antonio Maffia  Margaret Elizabeth Daub 《European journal of plant pathology / European Foundation for Plant Pathology》2014,139(2):235-238

Cercospora coffeicola is the causal agent of brown eye spot on coffee leaves. Although the disease has significant importance, few molecular studies have been done with C. coffeicola. Here we report a protocol for isolating protoplasts as well as development of a genetic transformation system using Green Fluorescent Protein. High yields of protoplasts (≈10⁸/ml) were obtained from mycelial cultures from five isolates of C. coffeicola. One isolate was transformed with a vector encoding hygromycin resistance and Green Fluorescent Protein. Out of 43 hygromycin-resistant transformants obtained, Green Fluorescent Protein was highly expressed in one (2.3 %).  相似文献   

Estimating nocturnal ecosystem respiration from the vertical turbulent flux and change in storage of CO₂     

Eva van Gorsel  Nicolas Delpierre  Ray Leuning  Andy Black  J. William Munger  Steven Wofsy  Marc Aubinet  Christian Feigenwinter  Jason Beringer  Damien Bonal  Baozhang Chen  Jiquan Chen  Robert Clement  Kenneth J. Davis  Ankur R. Desai  Danilo Dragoni  Sophia Etzold  Thomas Grünwald  Lianhong Gu  Bernhard Heinesch  Lucy R. Hutyra  Wilma W.P. Jans  Werner Kutsch  B.E. Law  Monique Y. Leclerc  Ivan Mammarella  Leonardo Montagnani  Asko Noormets  Corinna Rebmann  Sonia Wharton 《Agricultural and Forest Meteorology》2009,149(11):1919

Micrometeorological measurements of nighttime ecosystem respiration can be systematically biased when stable atmospheric conditions lead to drainage flows associated with decoupling of air flow above and within plant canopies. The associated horizontal and vertical advective fluxes cannot be measured using instrumentation on the single towers typically used at micrometeorological sites. A common approach to minimize bias is to use a threshold in friction velocity, u_*, to exclude periods when advection is assumed to be important, but this is problematic in situations when in-canopy flows are decoupled from the flow above. Using data from 25 flux stations in a wide variety of forest ecosystems globally, we examine the generality of a novel approach to estimating nocturnal respiration developed by van Gorsel et al. (van Gorsel, E., Leuning, R., Cleugh, H.A., Keith, H., Suni, T., 2007. Nocturnal carbon efflux: reconciliation of eddy covariance and chamber measurements using an alternative to the u_*-threshold filtering technique. Tellus 59B, 397–403, Tellus, 59B, 307-403). The approach is based on the assumption that advection is small relative to the vertical turbulent flux (F_C) and change in storage (F_S) of CO₂ in the few hours after sundown. The sum of F_C and F_S reach a maximum during this period which is used to derive a temperature response function for ecosystem respiration. Measured hourly soil temperatures are then used with this function to estimate respiration R_Rmax. The new approach yielded excellent agreement with (1) independent measurements using respiration chambers, (2) with estimates using ecosystem light-response curves of F_c + F_s extrapolated to zero light, R_LRC, and (3) with a detailed process-based forest ecosystem model, R_cast. At most sites respiration rates estimated using the u_*-filter, R_ust, were smaller than R_Rmax and R_LRC. Agreement of our approach with independent measurements indicates that R_Rmax provides an excellent estimate of nighttime ecosystem respiration.  相似文献