抗氧化剂对牛主动脉内皮细胞NF-κB激活的抑制作用

利用Western印迹法考查了过氧化氢和肿瘤坏死因子诱导的IκB α蛋白质降解 ,结果表明这两种物质能在相近的作用时间内诱导牛主动脉内皮细胞发生IκB α蛋白质降解 ,但是其作用强度有明显差异。结合免疫荧光染色技术检查NF κB的激活即核转位情况 ,考查了不同抗氧化剂对体外培养的牛主动脉血管内皮细胞转录因子NF κB激活现象的影响。结果表明吡咯烷二硫代氨基甲酸酯 (PDTC)能够明显抑制肿瘤坏死因子 (TNF α)诱导的IκB α蛋白质降解以及NF κB的核转位 ,供试的其他一些抗氧化剂也不同程度地抑制了TNF α诱导的IκB α蛋白质降解。     

体外冲击波碎石焦点附近声压分布的时域有限差分法数值解析

泌尿系统结石症是一种多发病。体外冲击波碎石(Extracorporealshockwavelithotropisy,ESWL)法是应用人体外发射的高强度脉冲超声波在人体内的焦点附近形成的冲击波破碎结石,被破碎的结石碎片随尿液排出体外的治疗泌尿系统结石症方法。由于这种治疗方法具有非创伤等优点而被广泛地应用于泌尿系统结石症的治疗。但是,ESWL治疗过程中有时会引发尿血、肾血肿等并发症,影响其治疗效果的主要因素之一为ESWL焦点附近形成的声压分布。在这里,利用作者等以前提出的时域有限差分(finitedifferencetimedomain,FDTD)超声波非线性传播的仿真方法,数值仿真ESWL超声波非线性传播过程,研究ESWL焦点附近声压的分布、焦点区域(焦区)的大小形状、高强度超声波形成的实际焦点位置。     

6-Phosphogluconate Dehydrogenase (6PGD) Gene Duplication in Kalimeris (Asteraceae)

Abstract The genus Kalimeris with a diagnostic character of short or inconspicuous pappus consists of two sections, Asteromoea and Cordifolium. As a result of 6PGD isozyme analysis, sect, Asteromoea, including 2 × and poly-ploid taxa from 5 × to 8 ×, show similar cytosolic isozyme multiplicity and share a monomorphic locus. The data suggest that gene duplication of polyploid members was derived from a common ancestor. K. miqueliana, belonging to sect. Cordifolium. also possessed a gene duplication in 6PGD, though significant differences were detected in electrophoretic mobility between the sections. The occurrence of gene duplication in East Asian diploid Astereae leaves intact the validity of the allopolyploid-origin hypothesis of n= 9, which was rejected by Gottlieb (1981a) in American Astereae.     

Lying to Pinocchio: floral deception in an orchid pollinated by long-proboscid flies

Plants that lack floral rewards may nevertheless attract pollinators if their flowers sufficiently resemble those of rewarding plants. Flowers of the South African terrestrial orchid Disa nervosa are similar in floral dimensions and spectral reflectance to those of a sympatric nectar-producing irid ( Watsonia densiflora s.l. ). Observations showed that the orchid and Watsonia share the same pollinator, a long-proboscid tabanid fly Philoliche aethiopica . These flies visited inflorescences of both species during their foraging bouts and most (64%) observed or captured on Watsonia inflorescences carried pollinaria of the orchid on their proboscides. They probe an average of 6.3 flowers on Watsonia inflorescences, but just 1.9 flowers on the Disa inflorescences, a behaviour which would strongly promote cross-pollination in the self-compatible orchid. The orchid generally achieves high levels of pollination success, with approximately 50% of flowers receiving or exporting pollen at some sites. Pollination success was also high at one site that lacked Watsonia plants, suggesting that the orchid does not have an obligate dependence on Watsonia . Its pollination system may therefore be characterized as intermediate between generalized food deception and specific floral mimicry.  © 2006 The Linnean Society of London, Botanical Journal of the Linnean Society , 2006, 152 , 271–278.     

Molecular phylogeny of the horse flies: a framework for renewing tabanid taxonomy

Horse flies, family Tabanidae, are the most diverse family‐level clade of bloodsucking insects, but their phylogeny has never been thoroughly explored using molecular data. Most adult female Tabanidae feed on nectar and on the blood of various mammals. Traditional horse fly classification tends towards large heterogeneous taxa, which impede much‐needed taxonomic work. To guide renewed efforts in the systematics of horse flies and their relatives, we assembled a dataset of 110 exemplar species using nucleotide data from four genes—mitochondrial CO1, and nuclear 28S, CAD and AATS. All commonly recognized tribes in Tabanidae are represented, along with outgroups in Tabanomorpha. The phylogeny is reconstructed using Bayesian inference, and divergence times are estimated using Bayesian relaxed clock methods with time constraints from tabanid fossils. Our results show Athericidae strongly supported as the lineage most closely related to Tabanidae, and Pangoniinae and Tabaninae as monophyletic lineages. However, Chrysopsinae is nonmonophyletic, with strong support for both a nonmonophyletic Bouvieromyiini and for Rhinomyzini as sister to Tabaninae. Only the tribes Philolichini, Chrysopsini, Rhinomyzini and Haematopotini are recovered as monophyletic, although Scionini is monophyletic with exclusion of the peculiar genus Goniops Aldrich. Mycteromyia Philippi and Adersia Austen, two enigmatic genera sometimes placed in separate family‐level groups, are recovered inside Pangoniini and Chrysopsini, respectively. Several species‐rich genera are not recovered as monophyletic, including Esenbeckia Rondani, Silvius Meigen, Dasybasis Macquart and Tabanus L. Tabanidae likely originated in the Cretaceous, and all major extant groups were present by the early Palaeogene. This newly revised phylogenetic framework for Tabanidae forms the basis for a new assessment of tabanid diversification and provides context for understanding the evolution of trophic specialization in horse flies.