经人工授精传播的猪病及其预防措施     

D.Maes  林可 《国外畜牧学(猪与禽)》2009,29(4):22-26

猪人工授精技术（Artificial insemination,AI）已在集约化养猪生产国中得到了广泛应用。人工授精是一种将优秀基因引入母猪群中的非常有效的工具,并能够将疾病传播的风险降至最小。然而,受到病原体污染的精液对生产实际的危害是巨大的。在已经从公猪精液中检测到的微生物中,大部分是非致病性的,但有一些是有名的病原体,如猪繁殖与呼吸综合症病毒,这部分病原体能给养猪业造成重大的经济损失。精液受到微生物的污染可能是由于公猪全身性感染和/或泌尿生殖道感染所致,或可能发生在精液采集、处理和存储过程中。这会导致精液品质下降,胚胎或胎儿死亡,以及受体母猪的子宫内膜炎和全身性感染和/或发病。用于从精液中分离细菌和病毒的常规技术因受多种原因的影响并不总是能获得理想的结果,这些原因包括所用技术缺乏敏感性和检测速度慢、对检测结果难以进行解释。近年来,PCR技术得到了普遍的应用,它们具有很高的敏感性,能很快获得检测结果,并且适合对大样本的检测。防止通过人工授精传播疾病的最佳方法是使用无特定病原体的公猪、对它们及其精液进行定期检测以及维持极高的生物安全水平。其它方法则应该侧重于利用合适的抗菌剂对精液进行处理,以及重点减少在采集、处理和存储过程中精液所受到的污染。  相似文献   

Effect of a cross-flow opening on the performance of a centrifugal fan in a combine harvester: Computational and experimental study     

Mekonnen Gebreslasie Gebrehiwot  Josse De Baerdemaeker  Martine Baelmans 《Biosystems Engineering》2010,105(2):247-256

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IUCN Red List of freshwater fishes and lampreys in Flanders (north Belgium)     

H. Verreycken  C. Belpaire  G. Van Thuyne  J. Breine  D. Buysse  J. Coeck  A. Mouton  M. Stevens  T. Van den Neucker  L. De Bruyn  D. Maes 《Fisheries Management and Ecology》2014,21(2):122-132

Red Lists are used to assess the extinction risk of species. Regional IUCN criteria were applied to categorise 42 indigenous freshwater fish species in Flanders into Red List categories. As such, three species are assessed as Regionally Extinct, eight as Critically Endangered, two as Endangered and eight as Vulnerable. A further five species are considered Near Threatened, 15 species as Least Concern and one species is Data Deficient. Five species disappeared from the Regionally Extinct category compared with the previous Red List (1988) as a consequence of improved water quality of estuaries and reintroduction programmes. In total, 62% of the freshwater fish species in Flanders was considered extinct or threatened. This is higher than neighbouring regions and Europe as a whole (44%). This new Red List of freshwater fishes in Flanders can be used to inform conservation actions.  相似文献   

Fast and sensitive on-site isothermal assay (LAMP) for diagnosis and detection of three fruit tree phytoplasmas     

K. De Jonghe  I. De Roo  M. Maes 《European journal of plant pathology / European Foundation for Plant Pathology》2017,147(4):749-759

Over the years, real-time PCR outflanked endpoint PCR in phytopathogen diagnostics, mainly because of the increase in sensitivity and timesaving aspects of the technique. However, a time consuming 16S rRNA-based nested PCR method is still the gold standard for phytoplasma diagnosis. This is also the case for phytoplasma detection in Malus, Pyrus and Prunus, the three main host plants of apple proliferation (AP), pear decline (PD) and European stone fruit yellows (ESFY) phytoplasma, respectively. The last decade, loop-mediated isothermal amplification (LAMP) (Notomi et al. 2000) is gaining a lot in significance and is also for phytoplasmas expected to become a widely used reliable diagnostic tool. High specificity and sensitivity which also requires a less stringent need for DNA purification, and the short analysis time and the limited equipment requirements makes the LAMP method a fast and affordable alternative with great point-of-care diagnostic potential. In this paper, we present a LAMP primer set for the ribosomal group 16SrX, containing the important fruit tree phytoplasmas AP, PD and ESFY. The primers were developed and validated for fast and sensitive detection and general use for diagnosis. We foresee that the LAMP technique will also have its application in on-site diagnosis of the fruit tree phytoplasmas during inspections and surveys.  相似文献   

Effect of host factors on the susceptibility of Rhododendron to Phytophthora ramorum     

I. De Dobbelaere  A. Vercauteren  N. Speybroeck  D. Berkvens  E. Van Bockstaele  M. Maes  K. Heungens 《Plant pathology》2010,59(2):301-312

Phytophthora ramorum causes sudden oak death (SOD) in western coastal forests of the USA. In Europe, the pathogen is mainly present in the nursery industry, particularly on Rhododendron. Because of the primary role of Rhododendron as a host and potentially as a vector, the effect of Rhododendron host factors on P. ramorum susceptibility and sporulation was investigated. Inoculation methods using either wounded or non‐wounded detached leaves were applied to 59 Rhododendron cultivars and 22 botanical species, replicated in three separate years. All Rhododendron species and cultivars were susceptible when using wounded leaves, but not when using non‐wounded leaves, suggesting a resistance mechanism operating at the level of leaf penetration. Using a regression tree analysis, the cultivars and species were split into four susceptibility classes. Young leaves were more susceptible than mature leaves when wounded, but less susceptible when non‐wounded. This effect was not correlated with leaf hydrophobicity or the number of leaf hairs. The presence or the type of rootstock did not affect the cultivar susceptibility level. Sporangia and chlamydospore production in the leaf lesions varied widely among Rhododendron cultivars and was not correlated with the susceptibility level. The susceptibility to P. ramorum correlated well with the susceptibility to P. citricola and P. hedraiandra × cactorum, suggesting that the resistance mechanisms against these species are non‐specific. Susceptibility to P. kernoviae was low for most cultivars. These findings have implications for detection, spread and disease control, and are therefore important in pest risk assessment.  相似文献   

QBOL: a new EU project focusing on DNA barcoding of Quarantine organisms     

P. Bonants  E. Groenewald  J. Y. Rasplus  M. Maes  P. de Vos  J. Frey  N. Boonham  M. Nicolaisen  A. Bertacini  V. Robert  I. Barker  L. Kox  M. Ravnikar  K. Tomankova  D. Caffier  M. Li  K. Armstrong  J. Freitas-Astúa  E. Stefani  J. Cubero  L. Mostert 《EPPO Bulletin》2010,40(1):30-33

In 2009 a new three year EU funded project (QBOL) started on DNA barcoding of important plant pests. An international consortium of 20 partners (universities, research institutes, and phytosanitary organizations) from around the world, coordinated by Plant Research International (Wageningen, the Netherlands), will collect DNA barcodes from many plant pathogenic quarantine organisms, store these sequences in a database accessible over the internet, develop a DNA bank and train end-users. All these activities should help National Plant Protection Services in the correct identification and detection of plant pathogenic quarantine organisms.  相似文献   

Characterization and taxonomic reassessment of the box blight pathogen Calonectria pseudonaviculata,introducing Calonectria henricotiae sp. nov.          下载免费PDF全文

B. Gehesquière  J. A. Crouch  R. E. Marra  K. Van Poucke  F. Rys  M. Maes  B. Gobin  M. Höfte  K. Heungens 《Plant pathology》2016,65(1):37-52

Calonectria pseudonaviculata, the causal agent of the disease of Buxus spp. known as ‘box blight’, was first detected in the mid‐1990s in the UK and New Zealand. Since then, the geographic range of box blight has rapidly expanded to at least 21 countries throughout temperate regions of the world, causing significant losses in nurseries, gardens and wild boxwood populations. This study determined the genetic diversity in a collection of 234 Calonectria isolates from diseased Buxus plants, originating from 15 countries and four continents. Two genetic clades, G1 and G2, were identified within this sample using multilocus phylogenetic analysis. The application of genealogical concordance phylogenetic species recognition criteria using four independent nuclear loci determined that the Calonectria isolates in these two clades are separate phylogenetic species. The isolates in the G1 clade were upheld as C. pseudonaviculata sensu stricto. Based on phylogenetic distinctiveness and the lack of mating, a new species is proposed, Calonectria henricotiae sp. nov., for the Calonectria isolates in the G2 clade. A PCR‐RFLP assay and real‐time PCR assays were developed to easily and reproducibly differentiate these species. To assess the practical implications of the identification of the two species, their physiology, fungicide susceptibility and pathogenicity were compared. No differences in pathogenicity were observed. However, C. henricotiae isolates exhibited greater thermotolerance and reduced sensitivity to specific triazole as well as strobilurin fungicides. The identification of a second phylogenetic species causing box blight may have a substantial impact on the epidemiology and control of this destructive disease.  相似文献   

Chronic toxicity of fenoxycarb to the midge Chironomus riparius after exposure in sediments of different composition     

Dirk Jungmann  Cornelia Bandow  Thomas Gildemeister  Roland Nagel  Thomas G. Preuss  Hans T. Ratte  Cândida Shinn  Lennart Weltje  Hanna M. Maes 《Journal of Soils and Sediments》2009,9(2):94-102

Background, aim, and scope  

Fenoxycarb is an insect growth regulator widely used to control a variety of pests. As a juvenile hormone analogue, it interacts with the natural hormones involved in insect development, inhibiting metamorphosis to the adult stage. Adverse effects of fenoxycarb on non-target organisms have been repeatedly observed and its rapid dissipation from water to the organic fraction of the sediment is known. The aim of this work was to investigate the impact of fenoxycarb on the development of sediment-dwelling larvae of the midge Chironomus riparius after exposure to spiked sediment.  相似文献   

Incidence of competitors and landscape structure as predictors of woodland-dependent birds     

Oliver Robertson  Martine Maron  Yvonne Buckley  Clive McAlpine 《Landscape Ecology》2013,28(10):1975-1987

Globally, modification of landscapes for agriculture has had a strong influence on the distribution and abundance of biota. In particular, woodland-dependent birds are under threat across agricultural landscapes in Britain, North America and Australia, with their decline and extirpation attributed to the loss and fragmentation of habitat. Other native species have become over-abundant in response to anthropogenic landscape change and have strong interactive effects on avian assemblage structure. In eastern Australia, the hyper-aggressive noisy miner (Manorina melanocephala) often dominates woodlands in agricultural landscapes through interspecific competition, resulting in declines of species richness of woodland-dependent birds. We aimed to determine the relative influence and importance of interspecific competition, in situ habitat structure and landscape structure for woodland-dependent bird species at the landscape level. We recorded species-specific landscape incidence of woodland-dependent birds in 24 agricultural-woodland mosaics (25 km²) in southern Queensland, Australia. We selected extensively cleared landscapes (10–23 % woodland cover) where fragmentation effects are expected to be greatest. We applied generalised linear models and hierarchical partitioning to quantify the relative importance of the landscape-level incidence of the noisy miner, mistletoe abundance, shrub cover, woodland extent, woodland subdivision and land-use intensity for the incidence of 46 species of woodland birds at the landscape-scale. The landscape-level incidence of the noisy miner was the most important explanatory variable across the assemblage. Both in situ habitat structure and landscape structure were of secondary importance to interspecific aggression, although previous research suggests that the increasing incidence of the noisy miner in fragmented agricultural landscapes is itself a consequence of anthropogenic changes to landscape structure. Species’ responses to fragmentation varied from positive to negative, but complex habitat structure had a consistently positive effect, suggesting in situ restoration of degraded habitats could be a conservation priority. Landscape wide conservation of woodland-dependent bird populations in agricultural landscapes may be more effective if direct management of noisy miner populations is employed, given the strong negative influence of this species on the incidence of woodland-dependent birds among landscapes.  相似文献   

Family- and school-based correlates of energy balance-related behaviours in 10-12-year-old children: a systematic review within the ENERGY (EuropeaN Energy balance Research to prevent excessive weight Gain among Youth) project     

Verloigne M  Van Lippevelde W  Maes L  Brug J  De Bourdeaudhuij I 《Public health nutrition》2012,15(8):1380-1395

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