Genetic diversity and differentiation among Lagopus lagopus populations in Scandinavia and Scotland: evolutionary significant units confirmed by SNP markers

Single Nucleotide Polymorphism in four Scandinavian populations of willow grouse (Lagopus lagopus) and two Scottish populations of red grouse (Lagopus lagopus scoticus) were assessed at 13 protein‐coding loci. We found high levels of diversity, with one substitution every 55 bp as an average and a total of 76 unlinked parsimony informative SNPs. Different estimators of genetic diversity such as: number of synonymous and non‐synonymous sites, average number of alleles, number and percentage of polymorphic loci, mean nucleotide diversity (π_s, π_a) and gene diversity at synonymous and non‐synonymous sites showed higher diversity in the northern populations compared to southern ones. Strong levels of purifying selection found in all the populations together with neutrality tests conforming to neutral expectations agree with large effective population sizes. Assignment tests reported a clear distinction between Scandinavian and Scottish grouse suggesting the existence of two different evolutionary significant units. The divergence time between willow and red grouse ranging between 12 500 and 125 000 years, in conjunction with the presence of ‘specific’ markers for each subspecies prompt a reassessment of the taxonomical status of the Scottish red grouse.     

Under a neighbour's influence: public information affects stress hormones and behaviour of a songbird

Socially acquired information improves the accuracy and efficiency of environmental assessments and can increase fitness. Public information may be especially useful during unpredictable food conditions, or for species that depend on resources made less predictable by human disturbance. However, the physiological mechanisms by which direct foraging assessments and public information are integrated to affect behaviour remain largely unknown. We tested for potential effects of public information on the behavioural and hormonal response to food reduction by manipulating the social environment of captive red crossbills (Loxia curvirostra). Red crossbills are irruptive migrants that are considered sensitive to changes in food availability and use public information in decision making. Here, we show that public information can attenuate or intensify the release of glucocorticoids (i.e. stress hormones) during food shortage in red crossbills. The observed modulation of corticosterone may therefore be a physiological mechanism linking public information, direct environmental assessments and behavioural change. This mechanism would not only allow for public information to affect individual behaviour, but might also facilitate group decision making by bringing group members into more similar physiological states. The results further suggest that stressors affecting entire populations may be magnified in individual physiology through social interactions.     

The impact of red howler monkey latrines on the distribution of main nutrients and on topsoil profiles in a tropical rain forest

Scarcity of organic matter and nutrients in the topsoil is a typical feature of lowland primary tropical rain forests. However, clumped defecation by vertebrate herbivore troops and further dung beetle processing may contribute to locally improve soil biological activity and plant growth. We studied the impact of clumped defecation by the red howler monkey (Alouatta seniculus), a frugivorous primate, on the vertical distribution of topsoil (0–6 cm) main nutrients and microstructures in a tropical rain forest (French Guiana). Three latrines, where monkey troops regularly defecate, were sampled, together with adjoining controls for carbon, nitrogen, phosphorus and microscopic components. The vertical distribution of C and N was affected by clumped defecation: nutrients were mostly restricted to the top 2 cm in control areas while latrines exhibited homogeneously distributed C and N, resulting in higher C and N content below 2 cm. No marked effect of defecation was registered on Olsen P. A small although significant increase in pH (0.1–0.3 pH units) and a marked increase in soil respiration (×1.5–2.5) were registered in latrines. Soil microstructures were studied by the small‐volume method. Variation according to depth, site and clumped defecation was analysed by Redundancy Analysis. The three latrines were characterized by an increase in root‐penetrated mineral‐organic assemblages, mainly composed of recent and old earthworm faeces. The local stimulation of plant roots, microbial and earthworm activity was prominent, together with an increase in soil fertility. Consequences for the regeneration of tropical rain forests in the Amazonian basin were discussed, in the light of existing knowledge.     

Phylogeographical, ecological and biological patterns shown by nuclear (ssrRNA and gGAPDH) and mitochondrial (Cyt b) genes of trypanosomes of the subgenus Schizotrypanum parasitic in Brazilian bats

The genetic diversity and phylogeographical patterns of Trypanosoma species that infect Brazilian bats were evaluated by examining 1043 bats from 63 species of seven families captured in Amazonia, the Pantanal, Cerrado and the Atlantic Forest biomes of Brazil. The prevalence of trypanosome-infected bats, as estimated by haemoculture, was 12.9%, resulting in 77 cultures of isolates, most morphologically identified as Trypanosoma cf. cruzi, classified by barcoding using partial sequences from ssrRNA gene into the subgenus Schizotrypanum and identified as T. cruzi (15), T. cruzi marinkellei (37) or T. cf. dionisii (25). Phylogenetic analyses using nuclear ssrRNA, glycosomal glyceraldehyde 3-phosphate dehydrogenase (gGAPDH) and mitochondrial cytochrome b (Cyt b) gene sequences generated three clades, which clustered together forming the subgenus Schizotrypanum. In addition to vector association, bat trypanosomes were related by the evolutionary history, ecology and phylogeography of the bats. Trypanosoma cf. dionisii trypanosomes (32.4%) infected 12 species from four bat families captured in all biomes, from North to South Brazil, and clustered with T. dionisii from Europe despite being separated by some genetic distance. Trypanosoma cruzi marinkellei (49.3%) was restricted to phyllostomid bats from Amazonia to the Pantanal (North to Central). Trypanosoma cruzi (18.2%) was found mainly in vespertilionid and phyllostomid bats from the Pantanal/Cerrado and the Atlantic Forest (Central to Southeast), with a few isolates from Amazonia.     

Feeding by the Newly Described Mixotrophic Dinoflagellate Paragymnodinium shiwhaense: Feeding Mechanism,Prey Species,and Effect of Prey Concentration

ABSTRACT. To investigate the feeding by the newly described mixotrophic dinoflagellate Paragymnodinium shiwhaense (GenBank accession number=AM408889), we explored the feeding process and the kinds of prey species that P. shiwhaense is able to feed on using several different types of microscopes, including a transmission electron microscope and high‐resolution video‐microscopy. In addition, we measured the growth and ingestion rates of P. shiwhaense on its optimal algal prey Amphidinium carterae as a function of prey concentration. We also measured these parameters for edible prey at a single concentration at which the growth and ingestion rates of P. shiwhaense on A. carterae were saturated. Paragymnodinium shiwhaense feed on algal prey using a peduncle after anchoring the prey by a tow filament. Among the algal prey offered, P. shiwhaense ingested small algal species that had equivalent spherical diameters (ESDs) ≤11 μm (e.g. the prymnesiophyte Isochrysis galbana, the cryptophytes Teleaulax sp. and Rhodomonas salina, the raphidophyte Heterosigma akashiwo, and the dinoflagellates Heterocapsa rotundata and A. carterae). However, it did not feed on larger algal species that had ESDs ≥12 μm (e.g. the dinoflagellates Prorocentrum minimum, Heterocapsa triquetra, Scrippsiella trochoidea, Alexandrium tamarense, Prorocentrum micans, Gymnodinium catenatum, Akashiwo sanguinea, and Lingulodinium polyedrum) or the small diatom Skeletonema costatum. The specific growth rates for P. shiwhaense feeding upon A. carterae increased rapidly with increasing mean prey concentration before saturating at concentrations of ca. 350 ng C/ml (5,000 cells/ml). The maximum specific growth rate (i.e. mixotrophic growth) of P. shiwhaense on A. carterae was 1.097/d at 20 °C under a 14:10 h light–dark cycle of 20 μE/m²/s, while its growth rate (i.e. phototrophic growth) under the same light conditions without added prey was ?0.224/d. The maximum ingestion and clearance rates of P. shiwhaense on A. carterae were 0.38 ng C/grazer/d (5.4 cells/grazer/d) and 0.7 μl/grazer/h, respectively. The calculated grazing coefficients for P. shiwhaense on co‐occurring Amphidinium spp. was up to 0.07/h (i.e. 6.7% of the population of Amphidinium spp. was removed by P. shiwhaense populations in 1 h). The results of the present study suggest that P. shiwhaense can have a considerable grazing impact on algal populations.     

Bioxun微柱凝胶筛查红细胞不规则抗体的研究

目的:探讨Bioxun微柱凝胶法(Bioxun Micro-column Gel anti-globulin Test,BMGT)筛查红细胞不规则抗体的敏感性和特异性。方法:使用盐水介质法(Saline Media Test,SMT)、传统抗人球法(Traditional anti-Globulin Test,TGT)、达亚美凝胶法(DiamedMicro-column Gel Test,DMGT)和Bioxun微柱凝胶法分别检测红细胞不规则抗体,对方法学灵敏度和特异性进行观察比较。结果:Bioxun微柱凝胶法与达亚美凝胶法的结果无显著差异(P>0.05),二者的敏感度和特异性超过盐水介质法和传统抗人球法(P<0.05)。结论:Bioxun微柱凝胶法操作快捷,敏感度高,适宜在临床输血中推广应用。     

基于连续统去除法的冬小麦叶片氮积累量的高光谱评价

作物氮素状况是评价长势、提高产量和改善品质的重要指标,它对作物氮素诊断与管理具有重要意义。本文基于不同施氮水平下的冬小麦冠层光谱及相应的叶片氮积累量数据,将广泛应用于岩矿高光谱分析中的连续统去除法借用至作物冠层氮素营养状况评价。通过对550~760nm波段的冠层光谱进行连续统去除处理,提取了3个吸收特征。结果表明:在所有生育期中,叶片氮积累量均随着施氮量的增加而增大;在所有氮处理中,从起身期、拔节期、孕穗期到抽穗期,叶片氮积累量均呈先增加后减小的趋势,且在孕穗期达到峰值;在各生育期,吸收峰总面积、吸收峰左面积和吸收峰右面积均随着施氮量的增加而增大,面积归一化最大吸收深度均随着施氮量的增加而减小。通过相关分析发现:各吸收特征参数与叶片氮积累量之间均存在显著性相关,且面积归一化最大吸收深度参数的相关性最好;全生育期的相关性高于各单生育期;但从单生育期来看,孕穗期是监测叶片氮积累量最佳时期。回归分析结果发现,基于全生育期建立的叶片氮积累量评价模型均达到了极显著性水平。     

鸡红细胞融合最适条件的探讨

目的:探讨快速、有效的细胞融合条件。方法:用鸡红细胞为材料,聚乙二醇(Mw=4000)为诱导剂,诱导鸡红细胞融合。结果:鸡红细胞融合的最适温度为39℃,最适时间为15min。结论:在该条件下,同时用Giemsa染液对融合细胞染色,实验观察效果明显。     

Comparison of the virulence plasmid genomes of two strains of Shigella which lost the ability to bind Congo red

As an enteric pathogen and Gram negative bacte-rium, Shigella possesses high infectivity and leads to serious illness. Since its discovery in 1898 by Shiga, Shigella species have been studied widely. These studies have elucidated the Shigella pathogenicit…