Field trial of a staphylococcal mastitis vaccine in dairy herds: clinical, subclinical and microbiological assessments

Objective To assess the efficacy of a new staphylococcal mastitis vaccine under commercial dairying conditions.
Design A field trial involving 1819 cows and heifers conducted on seven dairy herds in Victoria. The trial was done 'blind'; approximately half the animals were vaccinated and the remainder were untreated controls.
Procedure The vaccine was given twice during the last 10 weeks of pregnancy. Effects of vaccination were assessed, during the ensuing lactation, on the basis of clinical and sub-clinical mastitis and microbiological investigations of the milk.
Results A total of 273 cases of clinical mastitis were recorded. Staphylococcus aureus was isolated from 112 of these, 45 cases in vaccinates and 67 cases in controls; the difference was not statistically significant. One herd was notable in having a high incidence of clinical staphylococcal mastitis. This herd accounted for 15.8% of the animals in the field trial but 54.5% of cases of clinical staphylococcal mastitis. For this herd, vaccinated animals had significantly lower incidence of clinical staphylococcal mastitis and prevalence of subclinical mastitis, relative to controls. An unexpected feature of the trial as a whole was the low incidence of clinical mastitis from which S aureus was isolated in pure culture (26.3% of cases) and the high incidence of clinical Streptococcus uberis mastitis (22.7% of cases).
Conclusions The trial showed that the vaccine was efficacious in reducing the incidence of clinical mastitis and prevalence of subclinical mastitis in a herd that had a serious staphylococcal mastitis problem.     

优质蛋白玉米籽粒品质性状组间典型相关性研究

研究优质蛋白玉米籽粒品质性状组间典型相关性结果表明,2个半硬质胚乳奥帕克-2玉米群体(“中群14QPMC3”和“陕综5号QPMC0”)籽粒物理性状中硬质度、籽粒密度、百粒重与胚比、百粒体积呈负相关效应,营养品质中赖氨酸含量、蛋白质品质性状为其核心,籽粒密度(或硬质度)可作为蛋白质品质的间接选择指标;籽粒物理性状、蛋白质品质性状在赖氨酸产量构成中起决定性作用,全籽粒蛋白质品质与胚乳蛋白质品质紧密相关,而与胚蛋白质品质无关,高赖氨酸高油分育种相统一。     

From individual dispersal to species ranges: perspectives for a changing world

Dispersal is often risky to the individual, yet the long-term survival of populations depends on having a sufficient number of individuals that move, find each other, and locate suitable breeding habitats. This tension has consequences that rarely meet our conservation or management goals. This is particularly true in changing environments, which makes the study of dispersal urgently topical in a world plagued with habitat loss, climate change, and species introductions. Despite the difficulty of tracking mobile individuals over potentially vast ranges, recent research has revealed a multitude of ways in which dispersal evolution can either constrain, or accelerate, species' responses to environmental changes.     

anwendung der „vergleichsmethode standort (vermost)” zur bewertung der erosionsgefährdungspotenziale als datenbasis für förderinstrumente am beispiel des landes Brandenburg: Application of the site comparison method (vermost) to assess the potential erosion risk as a basis to examine instruments of environmental policy – the example of Brandenburg

This paper presents a comparative method (VERMOST) to evaluate complex site conditions at the level of a federal state (Brandenburg) and at different areal units. The methodology uses primary site conditions and provides the possibility to objectively compare and judge different ecological questions. Objects with heterogeneous content are pooled in comparison groups. Considering the main site characteristics allows a goal-oriented allocation of subsidies. The use of VERMOST is demonstrated for the wind and water erosion risk assessment across different scales from a federal state down to a parcel of land. The ‘parcel’ aggregation-level proves to be useful to assess the erosion risk. Larger scales are less useful in the assessment of subsidies policy with regard to erosion risk. A moving-window-technique combined with VERMOST is demonstrated to be suitable for comparing and assessing regional aspects more objectively compared with data administratively linked.     

Toxoplasma gondii seroprevalence in veterinarians in Finland: Older age,living in the countryside,tasting beef during cooking and not doing small animal practice associated with seropositivity

Practising veterinary medicine has an inherent risk of exposure to zoonotic agents, including the protozoan parasite Toxoplasma gondii. We screened sera of veterinarians authorized to work in Finland for the presence of specific immunoglobulin G antibodies against T. gondii with an enzyme‐linked fluorescent assay, and evaluated potential risk factors for T. gondii seropositivity from extensive questionnaire data with almost 1,300 quantitative variables. We used a causal diagram approach to address the complexity of the life cycle of the parasite and its numerous possible transmission routes, and built a multivariable binomial logistic regression model to identify risk factors that are particularly relevant for veterinarians. The samples and questionnaire data were collected in 2009. Altogether, 294 veterinarians, almost 15% of the Finnish veterinary profession, were included in the study. The median age was 39 years, and the majority, 86%, were women. Altogether, 43 (14.6%; 95% confidence interval: 10.9–19.0) of the 294 veterinarians tested seropositive for T. gondii. According to the final model, veterinarians who were at least 40 years old had 2.4 times higher odds to be seropositive than younger veterinarians; veterinarians who lived in the countryside had 4.0 times higher odds to be seropositive than veterinarians who lived in towns; female veterinarians who tasted beef during cooking had 2.6 times higher odds to be seropositive than male veterinarians who did not taste beef during cooking; and veterinarians who did not do small animal practice had 2.3 times higher odds to be seropositive than those who did. The results illustrate the numerous transmission routes of T. gondii.     

Genotypic variation in growth and physiological responses of Finnish hybrid aspen (Populus tremuloides x P. tremula) to elevated tropospheric ozone concentration

Saplings of six Finnish hybrid aspen (Populus tremuloides Michx. x P. tremula L.) clones were exposed to 0, 50, 100 and 150 ppb ozone (O3) for 32 days in a chamber experiment to determine differences in O3 sensitivity among genotypes. Based on the chamber experiment, three clones with intermediate sensitivity to O3 were selected for a free-air O3 enrichment experiment in which plants were exposed for 2 months to either ambient air (control) or air containing 1.3 x the ambient O3 concentration. We measured stem height and radial growth, number of leaves, dry mass and relative growth rate of leaves, stem and roots, visible leaf injuries, net photosynthesis and stomatal conductance of the clones. There was high clonal variation in susceptibility to O3 in the chamber experiment, indicated by foliar injuries and differential reductions in growth and net photosynthesis. In the free-air O3 enrichment experiment, ozone caused a shift in resource allocation toward stem height growth, thereby altering the shoot to root balance. In both experiments, low O3 concentrations tended to stimulate growth of most clones, whereas 100 and 150 ppb O3 in the chamber experiment impaired growth of most clones. However, growth of the most O3-tolerant clone was not significantly affected by any O3 treatment.     

New host for raspberry bushy dwarf virus: arctic bramble (Rubus arcticus)

Raspberry bushy dwarf virus (RBDV) was detected in three new host plants inRubus species,i.e., arctic bramble (R. arcticus ssp.arcticus), Alaskan arctic bramble (R. arcticus ssp.stellatus) and their hybrid (R. arcticus L. nothosubsp.stellarcticus G. Larsson). The virus was identified as RBDV by the symptoms elicited in the test plantsChenopodium quinoa andC. amaranticolor, by sedimentation profile in sucrose density gradient, by RNA banding pattern in agarose gel electrophoresis, by protein analysis of the purified viruses in SDS-polyacrylamide gel electrophoresis, and by Western blotting. There was a high incidence of RBDV-infected plants in the experimental plots. The presence of the virus in arctic bramble did not always induce foliar symptoms. However, yellowing of the leaves around central and lateral veins was quite frequently observed, especially in spring and autumn.     

Infection of alfalfa pollen bySclerotinia sclerotiorum

Blossom blight, caused bySclerotinia sclerotiorum, has become an important disease of alfalfa (Medicago sativa L.) in seed production areas of western Canada. Studies using light microscopy and scanning and transmission electron microscopy revealed that pollen grains of alfalfa are susceptible to infection byS. sclerotiorum. Ascospores ofS. sclerotiorum germinated readily in water with or without pollen grains. Examinations of ascospore—pollen mixtures incubated at room temperature (20–22°C) for 5 days revealed that numerous pollen grains were infected byS. sclerotiorum by direct hyphal penetration through the equatorial germinative pores or through the exine and intine layers of the pollen wall without the formation of infection cushions or appressoria. After penetration, hyphae ramified within the pollen grains, causing plasmolysis of the cytoplasmic membrane and eventual disintegration of the pollen cytoplasm. The study suggests that alfalfa pollen may play a role in the epidemiology of blossom blight in alfalfa.     

Negative frequency-dependent selection of sexually antagonistic alleles in Myodes glareolus

Sexually antagonistic genetic variation, where optimal values of traits are sex-dependent, is known to slow the loss of genetic variance associated with directional selection on fitness-related traits. However, sexual antagonism alone is not sufficient to maintain variation indefinitely. Selection of rare forms within the sexes can help to conserve genotypic diversity. We combined theoretical models and a field experiment with Myodes glareolus to show that negative frequency-dependent selection on male dominance maintains variation in sexually antagonistic alleles. In our experiment, high-dominance male bank voles were found to have low-fecundity sisters, and vice versa. These results show that investigations of sexually antagonistic traits should take into account the effects of social interactions on the interplay between ecology and evolution, and that investigations of genetic variation should not be conducted solely under laboratory conditions.     

Segmentation of Color Image Based on Feature Divergence and Fuzzy Theory

In order to improve general adaptive capability of algorithm,the new color image segmentation algorithm based on feature divergence and fuzzy theory(FDCIS) is proposed.The algorithm introduces feature divergence and fuzzy dissimilarity function into calculation in order to measure the dissimilarity of feature vector,clusters data by means of feature divergence,and accomplishes the merge of image region.The experimental results demonstrate that the color image segmentation result of the proposed approach reduce calculation on large sample of color image,simply and effectively solve over-segmentation of color image,avoid the dependence of the algorithm on initial condition,and hold favorable consistency in terms of human perception.