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1.
A study to evaluate BVDV-prevalence, recent -contact and -vaccine use in dairy herds in the "Entre Douro e Minho" (EDM) region in North Portugal was carried out in 124 dairy herds in 2003. Herds were visited to ascertain BVDV-vaccine use and to collect a bulk tank milk (BTM) sample and serum from 1268 cattle to analyse BVDV-antibodies using an NS2-3 ELISA. Fifty-three percent of farmers used inactivated BVDV-vaccines whilst the remaining farmers were not presently using BVDV-vaccines. BMT-antibody results included 35% positives, 25% negative and 39% inconclusive, and were similar in vaccinated and non-vaccinated herds (p>0.05) and allowed estimating a 10% BVDV herd-prevalence from prior knowledge of the relationship between BMT-antibody results and probability of PI cattle in the herd. Overall individual seroprevalence was 27% and was 23% in non-vaccinated and 36% in vaccinated cattle (p<0.05). Contact of the herd with BVDV was assessed according to seroprevalence in young and adult cattle in the herd and it was estimated that 35% of herds were infected or had recent contact with BVDV, 40% were not infected and did not have recent contact with BVDV and the BVDV-infection and -contact status of remaining herds was undetermined. The results from this study indicate BVDV is endemic and BVDV-vaccines are widespread in the dairy-cattle population in EDM region in Portugal.  相似文献   
2.
Availability of genetic diversity is important in selecting suitable cultivars for crop improvement. Progenies of crosses between 19 farmer-preferred cassava landraces and Cassava Mosaic Disease (CMD)-resistant cultivar TME 11 were evaluated and compared with their maternal parents to assess their genetic variability and genetic gains based on CMD tolerance, some growth variables and root yield. The combined analysis of variance for the traits showed significant genotypic differences amongst the progenies and the parents. Apart from a few instances, the differences in replications and years were also significant. Genetic variability components showed high heritability ranging from 92.3 to 99.6% and moderately high genetic gains of 54.1 to 99.6% for the parental cultivars. Apart from canopy spread and plant height, heritability and genetic gains of the progenies were slightly lower than the parents indicating high variability within families of the progenies. The phenotypic coefficient of variation was slightly greater than genotypic coefficient of variation indicating minimal influence of environment on the genotypes. For most of the characters evaluated, the mean performance of the progenies was higher than their corresponding parental lines. Although the genotypes differed significantly (P < 0.001) for all traits evaluated, cultivars such as Afebankye, Bosome nsia, Cedi bankye, 262 Debor, Kwadaso 25, Nkaakom 57 and Sisipe were found to constitute a pool of germplasm with adequate variability. The negative correlation between CMD incidence and other traits evaluated showed significant progress made in the breeding program.  相似文献   
3.
Owing to the increasing importance of aquaculture to compensate for the progressive worldwide reduction of natural fish and to the fact that several fish farming plants often suffer from heavy financial losses due to the development of infections caused by microbial pathogens, including multidrug resistant bacteria, more environmentally-friendly strategies to control fish infections are urgently needed to make the aquaculture industry more sustainable. The aim of this review is to briefly present the typical fish farming diseases and their threats and discuss the present state of chemotherapy to inactivate microorganisms in fish farming plants as well as to examine the new environmentally friendly approaches to control fish infection namely phage therapy and photodynamic antimicrobial therapy.  相似文献   
4.
The effect of right vs. left recumbency on computation of the vertebral heart score (VHS) was assessed in 63 healthy dogs. The VHS was significantly higher in right lateral recumbency (9.8 +/- 0.6 vs. 9.5 +/- 0.8; P < 0.0004). Gender and dog size did not significantly influence VHS values while there was m oredifference between left and right side measurements when considering the type of thorax (P = 0.055).  相似文献   
5.
Betanodaviruses are the causative agents of viral nervous necrosis and affect a broad range of fish species worldwide. Their bi-segmented genome is composed of the RNA1 and the RNA2 molecules encoding the viral polymerase and the coat protein, respectively. In southern Europe the presence of the RGNNV and the SJNNV genotypes, and the RGNNV/SJNNV and RGNNV/SJNNV reassortants has been documented. Several studies have reported a correlation between water temperature and disease onset. To explore the replication efficiency of betanodaviruses with different genomes in relation to temperature and to understand the role of genetic reassortment on viral phenotype, RGNNV, SJNNV, RGNNV/SJNNV and RGNNV/SJNNV field isolates were fully sequenced, and growth curves generated in vitro at four different temperatures (15, 20, 25, 30 °C) were developed for each isolate. The data obtained, corroborated by statistical analysis, demonstrated that viral titres of diverse betanodavirus genotypes varied significantly in relation to the incubation temperature of the culture. In particular, at 30 °C betanodaviruses under investigation presented different phenotypes, and viruses containing the RNA1 of the RGNNV genotype showed the best replication efficiency. Laboratory results demonstrated that viruses clustering within the same genotype based on the polymerase gene, possess similar growth kinetics in response to temperature, thus highlighting the key role of RNA1 in controlling viral replication at different environmental conditions. The results generated might have practical implications for the inference of viral phenotype according to genetic features and may contribute to a better understanding of betanodavirus ecology.  相似文献   
6.
To mitigate the impact and dissemination of clubroot in western Canada, canola (Brassica napus) producers have relied on clubroot resistance traits. However, in 2013 and 2014, new strains of the clubroot pathogen, Plasmodiophora brassicae, emerged that are virulent on most clubroot‐resistant (CR) canola genotypes. Novel strains of the pathogen were inoculated onto two susceptible canola cultivars, one resistant line and six CR cultivars. Although all cultivars/lines showed a susceptible response to inoculation with the new strains of P. brassicae, the severity of disease reaction, root hair infection rates and the amount of P. brassicae DNA present in each canola genotype varied depending on the strain. In addition, the effect of inoculum density on disease severity and gall formation was recorded for one of these new strains on a universally susceptible Chinese cabbage cultivar and one susceptible and 10 resistant canola genotypes. Although root galls were observed at an inoculum density of 103 spores per mL of soil, clear differentiation of susceptible and resistant reactions among canola cultivars/lines was not observed until the inoculum density reached 105 spores mL?1. At a spore density of 106 spores mL?1 and above, all cultivars/lines developed susceptible reactions, although there was some differentiation in the degree of reaction. This study shows the potential to develop a unique disease profile for emergent clubroot pathotypes and shows a useful range of spore densities at which to study new P. brassicae strains.  相似文献   
7.
In this study, we evaluate the use of polymerase chain reaction‐denaturing gradient gel electrophoresis (PCR‐DGGE) for monitoring the effect of different aquaculture practices on sediment prokaryote (Archaea and Bacteria) communities. The effect of initial fish (gilthead seabream Sparus aurata) stocking density on the structural diversity of prokaryote communities of earth ponds bottom sediments was evaluated using PCR‐DGGE after a 5 month grow‐out period. An identical approach was used to monitor the effect of supplying different fish feeds [commercial feed (CD) versus an ecofeed (ECO)]. One additional variable was the use of copper sulphate (CuSO4) as an algicide in some of the experimental rearing tanks. The statistical analyses of prokaryote community profiles showed that the presence of fish in earth ponds significantly influenced the structure of sediment prokaryote communities, when compared with earth ponds without fish, independently of the stocking density. Our results also indicated that the structure of the prokaryote communities of earth ponds supplied with the ECO feed shared a strong similarity with that fed CD. Curiously, the use of CuSO4 in ponds receiving the ECO feed promoted significant differences on the structural composition of the bacterial community, but not on the archaeal community. DGGE molecular fingerprints are suitable for fast evaluation of new management practices in food‐fish production on earth ponds by monitoring shifts on microbial communities in bottom sediments.  相似文献   
8.
Antimicrobial photodynamic therapy (aPDT) has emerged in the clinical field as a potential alternative to antibiotics to treat microbial infections. No cases of microbial viability recovery or any resistance mechanisms against it are yet known. 5,10,15-tris(1-Methylpyridinium-4-yl)-20-(pentafluorophenyl)-porphyrin triiodide (Tri-Py+-Me-PF) was used as photosensitizer. Vibrio fischeri and recombinant Escherichia coli were the studied bacteria. To determine the bacterial recovery after treatment, Tri-Py+-Me-PF (5.0 μM) was added to bacterial suspensions and the samples were irradiated with white light (40 W m−2) for 270 minutes. Then, the samples were protected from light, aliquots collected at different intervals and the bioluminescence measured. To assess the development of resistance after treatment, bacterial suspensions were exposed to white light (25 minutes), in presence of 5.0 μM of Tri-Py+-Me-PF (99.99% of inactivation) and plated. After the first irradiation period, surviving colonies were collected from the plate and resuspended in PBS. Then, an identical protocol was used and repeated ten times for each bacterium. The results suggest that aPDT using Tri-Py+-Me-PF represents a promising approach to efficiently destroy bacteria since after a single treatment these microorganisms do not recover their viability and after ten generations of partially photosensitized cells neither of the bacteria develop resistance to the photodynamic process.  相似文献   
9.
Wild populations of Vitis vinifera L.␣have been located in Portugal. Morphological characterization was carried out in three populations located in Alcácer do Sal, Castelo Branco, and Montemor-o-Novo, and then compared using multivariate discriminant analysis. These populations were from three different hydrological basins, therefore cross-pollination was not possible. It was verified that in each population all plants were different. The data suggest that the frequency of female and male plants is rather variable in wild populations. The morphology of the adult leaf, from the Alcácer do Sal population, had particular features when compared with Castelo Branco and Montemor-o-Novo populations, which were more homogeneous. The length of teeth compared with width at the end of the base, and the density of prostrate hairs between and on main veins (lower side) were the variables which allowed the best discrimination among populations.  相似文献   
10.

Forest governance is under reorganisation in many European countries, because of the changes in property and forest tenure rights. Portuguese community-based forestry is an interesting research subject from a New Institutional Economics perspective. Community forests (an important part of community lands known as baldios) cover half a million hectares in the north and the centre of the country and are owned by local communities. Their average size of over 400 hectares and diversity of resources underscore their value, and their management contributes to rural development. Recent laws intend for the complete transfer of their tenure rights to communities and local authorities. In this study, we analysed the transformational processes of Portuguese community-based forestry. To structure this analysis and shed light on forest management-related problems, we followed the 'four-level institutional analysis' developed by Williamson. Particular attention was paid to the first three levels. The first concerned social practice and informal rules. We are describing the history of baldios, their use by rural populations, and the subsequent occupation by the State for afforestation. The second level addressed the institutional environment and formal rules. Here, we focused on the recognition of baldio community properties and their legal framework development. The third level addressed management and the interaction of actors in transaction cost savings. Here, we examined the current community-based management models and future trends. In our analysis, we identified the causes underlying baldio management problems at different levels, which highlight the importance of new governance models and economic activities. The analysis showed that overall, the Portuguese community forest governance is a flexible structure capable of adapting to political and demographic changes and offering valuable support for the development of rural areas in the north and centre of the country. Additional empirical research is needed to improve knowledge on the impact of institutions on the management of community forests, both nationally and internationally.

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