Campylobacter from sows in farrow-to-finish pig farms: risk indicators and genetic diversity

Sows have been identified as a source of Campylobacter contamination in piglets. We carried out a one-year study, in 2008, at 53 farrow-to-finish farms in Brittany, France, to determine the proportion of sows excreting Campylobacter. We also determined the genotypes of the Campylobacter isolates. Moreover, Generalized Estimating Equations including repeated effects were used to assess the association between management practices and farm characteristics, and risk of Campylobacter shedding by sows. Per farm, 10 feces samples from sows were collected from selected sites (maternity, service area, gestation area) on the farms. Campylobacter isolates were identified by PCR and typed by PFGE. Campylobacter was detected in 25.1% of the 530 samples from sows, and 67% of the 53 pig farms had at least one positive sample (of 10 taken). All the Campylobacter isolates belonged to the Campylobacter coli species. They displayed a very high level of genetic diversity, also inside farms and few genotypes were common to several farms. Warmer months, large farms, and individual housing for sows were identified as risk indicators of Campylobacter shedding by sows. A short delay between sampling and treatment of the samples should be considered, to improve the detection of the bacterium in the feces samples.     

Marker-assisted selection efficiency in multiple connected populations: a simulation study based on the results of a QTL detection experiment in maize

Many studies already investigated marker-assisted selection (MAS) efficiency but mainly in biparental populations. Connected multiparental populations address a broader diversity and confer a gain of power for QTL detection which must be beneficial for MAS. Our objective was to compare multiparental connected designs to biparental populations taken separately for MAS and phenotypic selection. We first detected QTL for flowering time and grain yield in an experimental maize design involving four parental inbred lines crossed to produce six different biparental populations and confirmed the advantage of multiparental connected designs over biparental populations for QTL detection. Based on these results we performed stochastic simulations to evaluate the expected efficiency of four generations of MAS and phenotypic selection. Different parameters were considered: trait heritability, genetic architecture and whether QTL were assumed to be known or have to be detected. Genetic gains were higher in the multiparental design than on average over the biparental populations considered separately, especially when favourable alleles were equally distributed among parental lines. When QTL detection was included in the simulation process, we found that type I error risk considered for declaring QTL as significant should be adapted to the design. Type I error risks leading to the best response were higher for the biparental populations than for the multiparental design. Besides addressing a broader diversity, multiparental designs increase the power of QTL detection, which reinforces their superiority over biparental designs for MAS. Application of MAS to multiparental designs therefore appears promising to accelerate genetic gain in plant breeding programs.     

Cytotoxic activity of Origanum dictamnus

Several extracts of Origanum dictamnus, an endemic plant of Greece growing only in the island of Crete and the bioassay-directed isolated ursolic acid, were tested in vitro against the P388 (murine leukemia) and the human bronchial epidermoid cancer NSCLC-N6 (non small cell lung cancer) cell lines. Both the initial dichloromethane extract and the isolated from it ursolic acid exhibited cytotoxic activity. Ursolic acid was also tested in vivo, on murine ascite leukemia P388, where it exhibited at a dose of 50 mg/kg a marginal antileukemic activity.     

Hematologic and serum biochemistry values in two species of free-ranging porcupines (Coendou prehensilis, Coendou melanurus) in French Guiana.

Individuals of two porcupine species (Coendou prehensilis and Coendou melanurus) were translocated during the flooding of a forest at a hydroelectric dam site in French Guiana. Blood samples were collected for 11 mo to determine hematologic and serum chemistry reference mean values and ranges and to look for blood parasites. Male C. prehensilis had significantly higher hemoglobin levels, packed cell volumes, and creatinine and potassium values than did females of the same species. Coendou prehensilis had significantly lower amylase levels but higher creatinine, calcium, lactate dehydrogenase, and gamma glutamyl transferase levels than C. melanurus.     

Heart rate variability in relation to stress in the Asian elephant (Elephas maximus)

This study describes a safe, reliable, and accessible means to measure heart rate (HR) and HR variability (HRV) and evaluates the use of HRV as a physiological correlate of stress in the Asian elephant. A probabilistic model indicates that HRV measurements may adequately distinguish between stressed and non-stressed elephants.     

橡胶树树皮坏死:症状学、病原学、流行病学方面的发展和树干生理病症的发因

橡胶树排胶障碍是制约全球橡胶种植园发展的主要因素,它是由以下两个不同病症导致的:(1)割面干涸(TPD)-过度割胶引起的可逆生理反应,(2)割面树皮坏死(BN)-由橡胶树根颈韧皮部扩展的不可逆病变。树皮坏死(BN)目前危害了世界大部分胶园,胶园受害严重度取决于橡胶品种、树龄、种植地和种植地区。橡胶树树皮病的多态性一直是一个有争议的问题,通过对许多胶园的调研,该问题最近得到了解决。虽然前期和最近的病原分析不具决定性,但是环境因素却显示出同树皮坏死有联系。在对近期开割的胶园进行流行病调查,发现早期患病胶树地点呈非随机性。这些易发病区主要靠近沼泽地、路旁、风干行、原推土机过道、树林树桩残余地和斜坡缓冲地段的附近区域。在树皮坏死发生区,虽然没有发现与土壤化学因素有明显的关系,但是,土壤物理分析(如透度法)却表明,土壤的较高紧实度常同患病胶树的根系生长较弱有关联。另外,通常在芽接点接合处可以很好地观察到树皮坏死早期症状。通过PMS压力室获得的大量可比生态生理的测量数据显示,患病胶树呈现水分协迫特征,意味着病树树干同其根系存在着一种非理想的维管关系。因此,同土壤紧实度相关的土壤缺水状况、旱季不能满足胶树水分需求的脆弱根系、被扰乱的树液流动和土壤排水等因素的共同作用,被怀疑是诱导树干接芽区树皮坏死(坏死向上扩展到割面) 生理的一个主要外部诱因。在这些协迫的作用下,细胞与分子研究显示,橡胶树生理失调是导致树皮坏死迅速扩展的原因。在这些协迫的作用下,在胶树芽接部位的细胞破裂,释放极具扩散性的高浓度氰化物。在患病胶树的韧皮部生氰和解氰活动的极不协调,以及氰化物的释放,导致其周围的细胞受到毒害。最后, 这样一种多学科的研究方法为由协迫诱导的多因素生理病害研究提供了一个完整的新模式。     

Phylogeny of the ants: diversification in the age of angiosperms

We present a large-scale molecular phylogeny of the ants (Hymenoptera: Formicidae), based on 4.5 kilobases of sequence data from six gene regions extracted from 139 of the 288 described extant genera, representing 19 of the 20 subfamilies. All but two subfamilies are recovered as monophyletic. Divergence time estimates calibrated by minimum age constraints from 43 fossils indicate that most of the subfamilies representing extant ants arose much earlier than previously proposed but only began to diversify during the Late Cretaceous to Early Eocene. This period also witnessed the rise of angiosperms and most herbivorous insects.