Population structure and genetic diversity of Bromus tectorum within the small grain production region of the Pacific Northwest

Bromus tectorum L. is an invasive winter annual grass naturalized across the United States. Numerous studies have investigated B. tectorum population structure and genetics in the context of B. tectorum as an ecological invader of natural areas and rangeland. Despite the wealth of information regarding B. tectorum, previous studies have not focused on, or made comparisons to, B. tectorum as it persists in individual agroecosystems. The objectives of this study were to assess the genetic diversity and structure, the occurrence of generalist and specialist genotypes, and the influence of climate on distribution of B. tectorum sourced exclusively from within small grain production regions of the Pacific Northwest. Genetic diversity of B. tectorum sourced from agronomic fields was found to be similar to what has been observed from other land use histories. Six distinct genetic clusters of B. tectorum were identified, with no evidence to indicate that any of the genetic clusters were better adapted to a particular geographical area or climate within the region. Given the apparent random spatial distribution of B. tectorum genetic clusters at the spatial scale of this analysis, unique genotypes may be well mixed within region, similar to what was reported for other inbreeding weedy grass species.     

Tunable luminescence and energy transfer in Ca3SiO4Cl2:Ce3+,Li+,Mn2+,Eu2+ phosphors

A series of color‐tunable Ca_{3–2x‐y‐z}SiO₄Cl₂ (CSC):xCe³⁺,xLi⁺,yMn²⁺,zEu²⁺ phosphors with low temperature phase structure was synthesized via the sol–gel method. An energy transfer process from Ce³⁺ to Mn²⁺ in CSC:0.01Ce³⁺,0.01Li⁺,yMn²⁺ (y = 0.03–0.09) and the mechanism was verified to be an electric dipole–dipole interaction. The Ce³⁺ and Mn²⁺ emission intensities were greatly enhanced by co‐doping Eu²⁺ ions into CSC:0.01Ce³⁺,0.01Li⁺,0.07Mn²⁺ phosphors due to competitive energy transfers from Eu²⁺/Ce³⁺ to Mn²⁺, and Ce³⁺ to Eu²⁺. Under 332 nm excitation, CSC:0.01Ce³⁺,0.01Li+,0.07Mn²⁺,zEu²⁺ (z = 0.0005–0.002) exhibited tunable emission colors from green to white with coexisting orange, green and violet‐blue emissions. These phosphors could have potential application in white light‐emitting diodes.     

The impact of hyperglycemia on adhesion between endothelial and cancer cells revealed by single‐cell force spectroscopy

The impact of hyperglycemia on adhesion between lung carcinoma cells (A549) and pulmonary human aorta endothelial cells (PHAEC) was studied using the single‐cell force spectroscopy. Cancer cells were immobilized on a tipless Atomic Force Microscopy (AFM) cantilever and a single layer of endothelial cells was prepared on a glass slide. The measured force‐distance curves provided information about the detachment force and about the frequency of specific ligand‐receptor rupture events. Measurements were performed for different times of short term (up to 2 h) and prolonged hyperglycemia (3 h ‐ 24 h). Single‐cell force results were correlated with the expression of cell adhesion molecules (intercellular adhesion molecule, P‐selectin) and with the length and density of the PHAECs glycocalyx layer, which were measured by AFM nanoindentation. For short‐term hyperglycemia, we observed a statistically significant increase of the adhesion parameters that was accompanied by an increase of the glycocalyx length and expression of P‐selectin. Removal of hyaluronic acid from PHAECs glycocalyx significantly decreased the adhesion parameters, which indicates that hyaluronic acid has a strong impact on adhesion in A549/PHAEC system in short term of hyperglycemia. For prolonged hyperglycemia, the most significant increase of adhesion parameters was observed for 24 hours and this phenomenon correlated with the expression of adhesion molecules and a decrease of the glycocalyx length. Taking together, presented data indicate that both mechanical and structural properties of the endothelial glycocalyx strongly modulate the adhesion in the A549/PHAEC system.     

Genome‐wide analysis of Italian sheep diversity reveals a strong geographic pattern and cryptic relationships between breeds

Italy counts several sheep breeds, arisen over centuries as a consequence of ancient and recent genetic and demographic events. To finely reconstruct genetic structure and relationships between Italian sheep, 496 subjects from 19 breeds were typed at 50K single nucleotide polymorphism loci. A subset of foreign breeds from the Sheep HapMap dataset was also included in the analyses. Genetic distances (as visualized either in a network or in a multidimensional scaling analysis of identical by state distances) closely reflected geographic proximity between breeds, with a clear north–south gradient, likely because of high levels of past gene flow and admixture all along the peninsula. Sardinian breeds diverged more from other breeds, a probable consequence of the combined effect of ancient sporadic introgression of feral mouflon and long‐lasting genetic isolation from continental sheep populations. The study allowed the detection of previously undocumented episodes of recent introgression (Delle Langhe into the endangered Altamurana breed) as well as signatures of known, or claimed, historical introgression (Merino into Sopravissana and Gentile di Puglia; Bergamasca into Fabrianese, Appenninica and, to a lesser extent, Leccese). Arguments that would question, from a genomic point of view, the current breed classification of Bergamasca and Biellese into two separate breeds are presented. Finally, a role for traditional transhumance practices in shaping the genetic makeup of Alpine sheep breeds is proposed. The study represents the first exhaustive analysis of Italian sheep diversity in an European context, and it bridges the gap in the previous HapMap panel between Western Mediterranean and Swiss breeds.     

纳米金在基因突变检测及SNP分析中的应用

对特异核苷酸序列的高选择性检测在生物医学研究和临床检测中日趋重要. 纳米金特殊的光学性质、电学性质、化学性质、以及良好的生物相容性，使之成为检测生物大分子的首选工具.本文介绍了几种典型的基因突变检测及单核苷酸多态性(SNP)分析系统：基因芯片、生物传感器和光学检测系统.综述了多种颇有新意的检测方法和原理，详细阐明了它们的检测机制和研究进展，分析并比较了纳米金不同的作用方式，为纳米金在突变检测上的进一步研究提供了一定思路和参考.     

A polymorphism in the porcine miR‐208b is associated with microRNA biogenesis and expressions of SOX‐6 and MYH7 with effects on muscle fibre characteristics and meat quality

MicroRNAs (miRNAs) encoded by the myosin heavy chain (MHC) genes are muscle‐specific miRNAs (myomiRs) and regulate the expression of MHC isoforms in skeletal muscle. These miRNAs have been implicated in muscle fibre types and their characteristics by affecting the heterogeneity of myosin. In pigs, miR‐208b and miR‐499 are embedded in introns of MYH7 and MYH7b respectively. Here, we identified a novel single nucleotide polymorphism (SNP) in intron 30 of MYH7 by which porcine miR‐208b is encoded. Based on the association study using a total of 487 pigs including Berkshire (n = 164), Landrace (n = 121) and Yorkshire (n = 202), the miR‐208b SNP (g.17104G>A) had significant effects on the proportions of types I and IIb fibre numbers (P < 0.010) among muscle fibre characteristics and on drip loss (P = 0.012) in meat quality traits. Moreover, the SNP affected the processing of primary miR‐208b into precursor miR‐208b with a marginal trend towards significance (P = 0.053), thereby leading to significant changes in the levels of mature miR‐208b (P = 0.009). These SNP‐dependent changes in mature miR‐208b levels were negatively correlated with the expression levels of its target gene, SOX‐6 (P = 0.038), and positively associated with the expression levels of its host gene, MYH7 (P = 0.046). Taken together, our data suggest that the porcine miR‐208b SNP differentially represses the expression of SOX‐6 by regulating miRNA biogenesis, thereby affecting the expression of MYH7 and the traits of muscle fibre characteristics and meat quality.     

Diel fragrance pattern correlates with olfactory preferences of diurnal and nocturnal flower visitors in Salix caprea (Salicaceae)

Floral scent, often a complex mixture of several volatile organic compounds (VOCs), has generally been interpreted as an adaptation to attract pollinators. However, not many studies have analysed which VOCs are functionally relevant for the reproductive success of a plant. Here, we show that, in Salix caprea (Salicaceae), temporal changes in floral scent emission during the day and night attract two different types of flower visitor: bees during the day and moths during the evening and night. We analysed the contribution of the two flower visitor groups to the reproductive success of the plant. The differences in scent emitted during the peak activity times of flower visitors (day versus night) were quantified and the response of 13 diurnal/nocturnal pollinator taxa to the floral scents was tested using gas chromatographic and electroantennographic techniques. Many of the c. 40 identified scent compounds were physiologically active, and bees and moths responded to nearly identical sets of compounds, although the response strengths differed. In bioassays, bees preferred the most abundant 1,4‐dimethoxybenzene over lilac aldehyde, a compound with increased emission at night, whereas moths preferred lilac aldehyde over 1,4‐dimethoxybenzene. Pollination by wind plus nocturnal pollinators (mainly moths) or by wind alone contributed less to seed set than pollination by wind plus diurnal pollinators (mainly bees). This suggests that the emission of scent during the night and attracting moths have no significant effect on reproductive success. It is possible that the emission of lilac aldehydes and other compounds at night is s result of phylogenetic constraints. Future studies should investigate whether moths may produce a marginal fitness gain in some years and/or some populations. © 2014 The Linnean Society of London, Botanical Journal of the Linnean Society, 2014, 175 , 624–640.     

Association between COMT SNP variation and timidity in Golden and Labrador Retrievers

Timidity in dogs is a trait with high heritability. However, the relevant genetic factors and markers associated with this condition are largely unknown. The function of the catechol‐O‐methyl transferase (COMT) gene has been found to be associated with human fearful or anxious emotions, and the COMT:p.Val158Met polymorphism locus is significantly related to anxious behavior. In the present study, the correlation between timidity and four single nucleotide polymorphism (SNP) variations (C.‐1666C>G c.39A>G, c.216G>A, c.482G>A) of the COMT gene was investigated in dogs. The evaluation was based on the dog courage assessment assay and a genotype and haplotype analysis in Labrador Retrievers (LR) and Golden Retrievers (GR). The principal components analysis factor structure of the courage phenotype was invariant between LR and GR. Sex, breed and age had no statistically significant effect on the timidity of the dogs. All SNP loci detected were in Hardy–Weinberg equilibrium. The c.39A>G locus was removed in the subsequent association analysis due to the significant difference between LR and GR in genotype distributions. Intriguingly, the genotypes and haplotypes of the COMT gene were significantly and highly correlated with the timidity of LR and GR. The A alleles of the COMT:c.216G>A and c.482G>A loci appeared to play a dominant role in the timid behavior of the dogs. This result supports and broadens the warrior/worrier hypothesis and will have important implications for the understanding of the evolution of temperament in dogs. Additionally, the results provide predictive genetic markers for temperament in dogs.     

云南菜食花植物资源与食花文化调查

为了摸清云南省菜食花植物资源种类、自然分布与食用地区、食用方法等土著知识,对云南省16个地州102个县(市)农贸市场、地方菜餐馆、民间食花者进行了访问调查,对菜食花植物进行了植物学实地鉴定。调查到云南省菜食花植物140种,隶属52科108属,其中木本植物82种,草本植物58种;人工栽培76种,人工驯化栽培14种,野生资源50种。首次报道苦绳(Dregea sinensis Hemsl.)、云南山楂(Crataegus scabrifolia(Franch.)Rehder)、滇海水仙花(Primula pseudodenticulata Pax)、长毛黄葵(Abelmoschus crinitus Wall.)、尖叶美容杜鹃(Rhododendron caloplytum var.openshawianum(Rehd.et Wils.)Chamb.)、大纽子花(Vallaris indecora(Baill.)Tsiang et P.T.Li)、大花虫豆(Cajanus grandiflorus(Benth.ex Baker)Maesen Vaniot der Maesen)、须弥葛(Pueraria wallichii DC.)、白花灯笼(Clerodendrum fortunatum L.)等9种植物的花可以做菜食用。菜食花植物自然分布区与食用地区并非完全重叠,食用地区一般分布有该植物,而分布有该植物的地区不一定食用;食用种类具有从南向北逐渐减少的特点,与食花植物丰富度和少数民族有一定的关系;食花习俗具有一定的民族性,主要体现食花的种类和烹饪口味上。不同菜食花食用的部位不同,烹饪方式也呈多样化。本文针对食用花传统文化的消失与野生菜食花资源的开发利用提出了相关建议。