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91.
Spermatological characters of the liver fluke Mediogonimus jourdanei Mas-Coma et Rocamora, 1978 were studied by means of transmission and scanning electron microscopy. Spermiogenesis begins with the formation of the differentiation zone containing two centrioles associated with striated rootlets and an intercentriolar body. These two centrioles originate two free flagella that undergo a 90 degrees rotation before fusing with the median cytoplasmic process. Both nuclear and mitochondrial migrations toward the median cytoplasmic process occur before the proximodistal fusion of flagella. Finally, the constriction of the ring of arched membranes gives rise to the young spermatozoon. The mature sperm of M. jourdanei measures about 260 microm and presents two axonemes of different lengths with the typical pattern of the Trepaxonemata, two bundles of parallel cortical microtubules, one mitochondrion, a nucleus and granules of glycogen. An analysis of all the microphalloidean species studied to date emphasised some differences in certain characters found in Maritrema linguilla J?gerski?ld, 1908 and Ganeo tigrinum Mehra et Negi, 1928 in comparison to those in the remaining microphalloideans. The presence and variability of such ultrastructural characters according to family, superfamily or order have led several authors to propose their use in the analysis of trematode relationships and phylogeny. Therefore, apart from producing new data on the family Prosthogonimidae, the present study also compares the spermatological organization of M jourdanei with other available ultrastructural studies focusing on the Microphalloidea. 相似文献
92.
Laura González Raúl Bermejo María Asunción Parra David Elustondo Jordi Garrigó Jesús Miguel Santamaría 《Water, air, and soil pollution》2010,206(1-4):23-34
Ground-level dynamics of O3, NO x and benzene, toluene, ethylbenzene and xylenes were characterised at rural sites in the medium Ebro River Basin (Northern Spain) from April to September (2003–2007) and by means of automated and passive monitoring. The study registered high O3 levels within the area, which were influenced by traffic emissions, and a monthly evolution of these levels consistent with the occurrence of a broad summer maximum, typical of polluted areas. The mean ozone concentration registered in the studied area by means of passive sampling was 87?±?12 μg m?3. The 2008/50/EC objective value for the protection of vegetation was widely exceeded during this study (AOT40?=?57,147?±?14,114 μg m?3 h), suggesting that current ambient levels may pose a risk for crops and vegetation in this important agroindustrial region. 相似文献
93.
Maribel Casas Raquel Cortés Sonia Pina Bibiana Peralta Alberto Allepuz Martí Cortey Jordi Casal Marga Martín 《Veterinary microbiology》2011
Hepatitis E is a zoonotic disease and is highly prevalent in European swine livestock. There is a need to compare the infection dynamics of hepatitis E virus (HEV) between herds with the same production system and determine the percentage of animals that could arrive infected at slaughter age. Therefore, a longitudinal study was performed in six Spanish farrow-to-finish affected farms. Twenty piglets per farm were monitored from nursery to slaughter. RT-PCR and serology techniques were applied to analyze longitudinally collected sera and/or faecal samples. Liver and bile samples were also taken at the abattoir. Anti-HEV IgM were firstly detected at 7 weeks of age in 5 farms whereas at 13 weeks of age in 1 farm (farm 2). At slaughter age 50–100% of pigs had seroconverted to anti-HEV IgG in the former 5 farms whereas in the other herd only 5% of pigs were IgG seropositive (farm 2). Six out of 96 livers and 5 out of 80 biles analyzed were HEV positive at the abattoir (total percentage of infected animals: 11.5%). All these positive animals had already seroconverted except 2 pigs of farm 2. Hence, pigs can be seronegative at slaughter age being infected during the latest fattening period. Manipulation of HEV-infected livers or other organs from pigs could be considered a possible route of transmission in Spanish abattoirs. This study represents the first longitudinal survey on swine HEV infection dynamics conducted in different herds. 相似文献
94.
Evaluation of plant-based water status indicators in mature apple trees under field conditions 总被引:1,自引:0,他引:1
The performance of different indicators of plant water status as a tool for irrigation management was evaluated in mature
field grown ‘Golden Delicious’ apple trees during the late summer of 1998. Control (C) and stress (S) treatments were studied.
In the C treatment trees were irrigated daily at 100% ETc whereas in the S treatment water was withheld during 31 days (DOY’s 236–266). Predawn water potential (Ψpd) and midday stem water potential (Ψstem) were measured several times a week during the experimental period. Three daily measurements of stomatal conductance (gs) and stem water potential were made during five consecutive days in mid-September. Trunk diameter changes (TDC) were recorded
by LVDT sensors, and from these measurements, maximum daily shrinkage (MDS), daily growth (DG), and cumulative growth (CG)
were calculated. Midday Ψstem showed the best ratio between the response to moderate water stress and tree variability (“signal/noise” ratio) among the
indicators studied here, followed closely by Ψpd. On the other hand, the poorest water status indicator was gs. Due to the low trunk growth rate of the trees, and its high variability, DG and CG were not adequate indicators. MDS showed
a lower sensitivity to water stress and a higher variability (CV = 0.19) than midday Ψstem (CV = 0.08) and Ψpd (CV = 0.10). However, MDS correlated well with ET0 and with midday Ψstem (R
2 = 0.79) thus, making this parameter an interesting and promising tool for irrigation management in apple orchards. More research
needs to be done in order to define reference values for MDS and plant water potential indicators, in relation to evaporative
conditions and in different phenological periods, and to quantify the relationship between water status indicators values
and apple tree yield and fruit quality. 相似文献
95.
Studies of ecological networks (the web of interactions between species in a community) demonstrate an intricate link between a community's structure and its long-term viability. It remains unclear, however, how much a community's persistence depends on the identities of the species present, or how much the role played by each species varies as a function of the community in which it is found. We measured species' roles by studying how species are embedded within the overall network and the subsequent dynamic implications. Using data from 32 empirical food webs, we find that species' roles and dynamic importance are inherent species attributes and can be extrapolated across communities on the basis of taxonomic classification alone. Our results illustrate the variability of roles across species and communities and the relative importance of distinct species groups when attempting to conserve ecological communities. 相似文献
96.
Yuliaxis Ramayo-Caldas Laura Zingaretti Milka Popova Jordi Estellé Aurelien Bernard Nicolas Pons Pau Bellot Núria Mach Andrea Rau Hugo Roume Miguel Perez-Enciso Philippe Faverdin Nadège Edouard Dusko Ehrlich Diego P. Morgavi Gilles Renand 《Zeitschrift für Tierzüchtung und Züchtungsbiologie》2020,137(1):49-59
Mitigation of greenhouse gas emissions is relevant for reducing the environmental impact of ruminant production. In this study, the rumen microbiome from Holstein cows was characterized through a combination of 16S rRNA gene and shotgun metagenomic sequencing. Methane production (CH4) and dry matter intake (DMI) were individually measured over 4–6 weeks to calculate the CH4 yield (CH4y = CH4/DMI) per cow. We implemented a combination of clustering, multivariate and mixed model analyses to identify a set of operational taxonomic unit (OTU) jointly associated with CH4y and the structure of ruminal microbial communities. Three ruminotype clusters (R1, R2 and R3) were identified, and R2 was associated with higher CH4y. The taxonomic composition on R2 had lower abundance of Succinivibrionaceae and Methanosphaera, and higher abundance of Ruminococcaceae, Christensenellaceae and Lachnospiraceae. Metagenomic data confirmed the lower abundance of Succinivibrionaceae and Methanosphaera in R2 and identified genera (Fibrobacter and unclassified Bacteroidales) not highlighted by metataxonomic analysis. In addition, the functional metagenomic analysis revealed that samples classified in cluster R2 were overrepresented by genes coding for KEGG modules associated with methanogenesis, including a significant relative abundance of the methyl-coenzyme M reductase enzyme. Based on the cluster assignment, we applied a sparse partial least-squares discriminant analysis at the taxonomic and functional levels. In addition, we implemented a sPLS regression model using the phenotypic variation of CH4y. By combining these two approaches, we identified 86 discriminant bacterial OTUs, notably including families linked to CH4 emission such as Succinivibrionaceae, Ruminococcaceae, Christensenellaceae, Lachnospiraceae and Rikenellaceae. These selected OTUs explained 24% of the CH4y phenotypic variance, whereas the host genome contribution was ~14%. In summary, we identified rumen microbial biomarkers associated with the methane production of dairy cows; these biomarkers could be used for targeted methane-reduction selection programmes in the dairy cattle industry provided they are heritable. 相似文献
97.
Francesca Romana Massacci Silvia Tofani Claudio Forte Micol Bertocchi Carmela Lovito Serenella Orsini Michele Tentellini Lucia Marchi Gaetan Lemonnier Diana Luise Fany Blanc Adrien Castinel Claudia Bevilacqua Claire Rogel-Gaillard Giovanni Pezzotti Jordi Estellé Paolo Trevisi Chiara Francesca Magistrali 《Zeitschrift für Tierzüchtung und Züchtungsbiologie》2020,137(1):60-72
Enterotoxigenic Escherichia coli (ETEC) is the aetiological agent of postweaning diarrhoea (PWD) in piglets. The SNPs located on the Mucine 4 (MUC4) and Fucosyltransferase 1 (FUT1) genes have been associated with the susceptibility to ETEC F4 and ETEC F18, respectively. The interplay between the MUC4 and FUT1 genotypes to ETEC infection and the use of amoxicillin in modifying the intestinal microbiota during a natural infection by multiresistant ETEC strains have never been investigated. The aim of this study was to evaluate the effects of the MUC4 and FUT1 genotypes and the administration of amoxicillin through different routes on the presence of diarrhoea and the faecal microbiota composition in piglets naturally infected with ETEC. Seventy-one piglets were divided into three groups: two groups differing by amoxicillin administration routes—parenteral (P) or oral (O) and a control group without antibiotics (C). Faecal scores, body weight, presence of ETEC F4 and F18 were investigated 4 days after the arrival in the facility (T0), at the end of the amoxicillin administration (T1) and after the withdrawal period (T2). The faecal bacteria composition was assessed by sequencing the 16S rRNA gene. We described that MUC4 and FUT1 genotypes were associated with the presence of ETEC F4 and ETEC F18. The faecal microbiota was influenced by the MUC4 genotypes at T0. We found the oral administration to be associated with the presence of diarrhoea at T1 and T2. Furthermore, the exposure to amoxicillin resulted in significant alterations of the faecal microbiota. Overall, MUC4 and FUT1 were confirmed as genetic markers for the susceptibility to ETEC infections in pigs. Moreover, our data highlight that group amoxicillin treatment may produce adverse outcomes on pig health in course of multiresistant ETEC infection. Therefore, alternative control measures able to maintain a healthy faecal microbiota in weaners are recommended. 相似文献
98.
Napp S Gubbins S Calistri P Allepuz A Alba A García-Bocanegra I Giovannini A Casal J 《Veterinary research》2011,42(1):4
ABSTRACT: Even though bluetongue virus (BTV) transmission is apparently interrupted during winter, bluetongue outbreaks often reappear in the next season (overwintering). Several mechanisms for BTV overwintering have been proposed, but to date, their relative importance remain unclear. In order to assess the probability of BTV overwintering by persistence in adult vectors, ruminants (through prolonged viraemia) or a combination of both, a quantitative risk assessment model was developed. Furthermore, the model allowed the role played by the residual number of vectors present during winter to be examined, and the effect of a proportion of Culicoides living inside buildings (endophilic behaviour) to be explored. The model was then applied to a real scenario: overwintering in Germany between 2006 and 2007. The results showed that the limited number of vectors active during winter seemed to allow the transmission of BTV during this period, and that while transmission was favoured by the endophilic behaviour of some Culicoides, its effect was limited. Even though transmission was possible, the likelihood of BTV overwintering by the mechanisms studied seemed too low to explain the observed re-emergence of the disease. Therefore, other overwintering mechanisms not considered in the model are likely to have played a significant role in BTV overwintering in Germany between 2006 and 2007. 相似文献
99.
Rodrigo M.P. Paiva DVM MS Lain Garcia-Guasch DVM MS PhD Jordi Manubens DVM Jose Alberto Montoya-Alonso DVM MS PhD 《Journal of Veterinary Cardiology》2011,13(4):267-270
The proximal isovelocity surface area (PISA) principles and methodology have been described in human and veterinary medicine with special emphasis given to the ease and speed for the quantification of mitral regurgitation. Although limitations have been described in both human and veterinary medicine, in the case of veterinary medicine, clinical examples have not been well defined and in some cases have not been individually presented. The objective of this paper is to illustrate in a qualitative manner the echocardiographic existence of the dynamic behavior and variability of mitral regurgitation in dogs with mitral valve prolapse, a factor to be taken into consideration as a limitation inherent to the PISA technique. 相似文献
100.
Jordi López-Alvarez LltVet MRCVS Sonja Fonfara Dr Med Vet MRCVS Brigite Pedro DVM MRCVS Hannah Stephenson BVMS MRCVS Peter J. Cripps BSc BVSc MSc PhD MRCVS Joanna Dukes-McEwan BV MS MVM PhD MRCVS 《Journal of Veterinary Cardiology》2011,13(3):183-195