Ventral specification and perturbed boundary formation in the mouse midbrain in the absence of Hedgehog signaling.

Although Hedgehog (HH) signaling plays a critical role in patterning the ventral midbrain, its role in early midbrain specification is not known. We examined the midbrains of sonic hedgehog (Shh) and smoothened (Smo) mutant mice where HH signaling is respectively attenuated and eliminated. We show that some ventral (Evx1+) cell fates are specified in the Shh-/- mouse in a Ptc1- and Gli1-independent manner. HH-independent ventral midbrain induction was further confirmed by the presence of a Pax7-negative ventral midbrain territory in both Shh-/- and Smo-/- mice at and before embryonic day (E) 8.5. Midbrain signaling centers are severely disrupted in the Shh-/- mutant. Interestingly, dorsal markers are up-regulated (Wnt1, Gdf7, Pax7), down-regulated (Lfng), or otherwise altered (Zic1) in the Shh-/- midbrain. Together with the increased cell death seen specifically in Shh-/- dorsal midbrains (E8.5-E9), our results suggest specific regulation of dorsal patterning by SHH, rather than a simple deregulation due to its absence.     

牛膝指纹图谱分析

目的:对不同产地牛膝药材、同一产地不同规格牛膝药材的HPLC指纹图谱进行研究,比较不同产地牛膝药材、同一产地不同规格牛膝药材的HPLC指纹图谱差异,探讨产地、规格对牛膝药材质量的影响及规格与牛膝药材内部质量的联系;为牛膝药材的产地鉴别提供理论依据;为牛膝药材质量标准制定、规格完善及临床用药提供参考。方法:采用超声提取法制备样品,通过HPLC法采集不同产地牛膝药材、同一产地不同规格牛膝药材的指纹图谱,运用相似度、聚类分析、主成分分析的方法进行分析,并比较不同产地牛膝药材、不同规格牛膝药材的HPLC指纹图谱差异。结果:不同产地分析,主成分分析能将5个产地牛膝药材区分开,且产地鉴别结果优于聚类分析和相似度分析。不同规格分析,相似度和主成分分析均不能将不同规格牛膝药材区分开。结论:不同产地牛膝药材化学成分种类、峰高差异显著;不同规格牛膝药材化学成分种类、峰高差异较小;主成分分析可用于牛膝药材的产地鉴别。     

Probing early heart development to instruct stem cell differentiation strategies

Scientists have studied organs and their development for centuries and, along that path, described models and mechanisms explaining the developmental principles of organogenesis. In particular, with respect to the heart, new fundamental discoveries are reported continuously that keep changing the way we think about early cardiac development. These discoveries are driven by the need to answer long‐standing questions regarding the origin of the earliest cells specified to the cardiac lineage, the differentiation potential of distinct cardiac progenitor cells, and, very importantly, the molecular mechanisms underlying these specification events. As evidenced by numerous examples, the wealth of developmental knowledge collected over the years has had an invaluable impact on establishing efficient strategies to generate cardiovascular cell types ex vivo, from either pluripotent stem cells or via direct reprogramming approaches. The ability to generate functional cardiovascular cells in an efficient and reliable manner will contribute to therapeutic strategies aimed at alleviating the increasing burden of cardiovascular disease and morbidity. Here we will discuss the recent discoveries in the field of cardiac progenitor biology and their translation to the pluripotent stem cell model to illustrate how developmental concepts have instructed regenerative model systems in the past and promise to do so in the future. Developmental Dynamics 245:1130–1144, 2016. © 2016 Wiley Periodicals, Inc.     

Amnioserosa development and function in Drosophila embryogenesis: Critical mechanical roles for an extraembryonic tissue

Despite being a short‐lived, extraembryonic tissue, the amnioserosa plays critical roles in the major morphogenetic events of Drosophila embryogenesis. These roles involve both cellular mechanics and biochemical signaling. Its best‐known role is in dorsal closure—well studied by both developmental biologists and biophysicists—but the amnioserosa is also important during earlier developmental stages. Here, we provide an overview of amnioserosa specification and its role in several key developmental stages: germ band extension, germ band retraction, and dorsal closure. We also compare embryonic development in Drosophila and its relative Megaselia to highlight how the amnioserosa and its roles have evolved. Placed in context, the amnioserosa provides a fascinating example of how signaling, mechanics, and morphogen patterns govern cell‐type specification and subsequent morphogenetic changes in cell shape, orientation, and movement. Developmental Dynamics 245:558–568, 2016. © 2016 Wiley Periodicals, Inc.     

Ascidian embryonic development: An emerging model system for the study of cell fate specification in chordates

The ascidian tadpole larva represents the basic body plan of all chordates in a relatively small number of cells and tissue types. Although it had been considered that ascidians develop largely in a determinative way, whereas vertebrates develop in an inductive way, recent studies at the molecular and cellular levels have uncovered several similarities in the way developmental fates are specified. In this review, we describe ascidian embryogenesis and its cell lineages, introduce several characteristics of ascidian embryos, describe recent advances in understanding of the mechanisms of cell fate specification, and discuss them in the context of what is known in vertebrates and other organisms. Developmental Dynamics 236:1748–1757, 2007. © 2007 Wiley‐Liss, Inc.     

A comparative study of plateletpheresis using Baxter Autopheresis C and Haemonetics PCS Plus

SUMMARY. This study compared plateletpheresis on the Haemonetics PCS Plus (PCS Plus) and the Baxter Autopheresis C (Auto C) using the same 100 selected donors. The number of packs meeting UK BTS/NIBSC specification (>2.2 times 10¹¹ platelets per pack) was achieved by 99% of PCS Plus and 82% of Auto C procedures. The positive correlation found between donor precount and final platelet yield was better for the PCS Plus. Both machines met U.K. specification for white-cell contamination but this was significantly greater for the Auto C. Plasma yields were similar.
As a result of this study we chose to use the PCS Plus for routine plateletpheresis in our unit. This has enabled us not only to comply with UK BTS/NIBSC specifications for apheresis platelets easily and cost effectively but also to meet our own higher specification (2.75 times 10¹¹ platelets per pack) using existing staff and without extending the working day.     

In silico identification of anthropogenic chemicals as ligands of zebrafish sex hormone binding globulin

Anthropogenic compounds with the capacity to interact with the steroid-binding site of sex hormone binding globulin (SHBG) pose health risks to humans and other vertebrates including fish. Building on studies of human SHBG, we have applied in silico drug discovery methods to identify potential binders for SHBG in zebrafish (Danio rerio) as a model aquatic organism. Computational methods, including; homology modeling, molecular dynamics simulations, virtual screening, and 3D QSAR analysis, successfully identified 6 non-steroidal substances from the ZINC chemical database that bind to zebrafish SHBG (zfSHBG) with low-micromolar to nanomolar affinities, as determined by a competitive ligand-binding assay. We also screened 80,000 commercial substances listed by the European Chemicals Bureau and Environment Canada, and 6 non-steroidal hits from this in silico screen were tested experimentally for zfSHBG binding. All 6 of these compounds displaced the [³H]5α-dihydrotestosterone used as labeled ligand in the zfSHBG screening assay when tested at a 33 μM concentration, and 3 of them (hexestrol, 4-tert-octylcatechol, and dihydrobenzo(a)pyren-7(8H)-one) bind to zfSHBG in the micromolar range. The study demonstrates the feasibility of large-scale in silico screening of anthropogenic compounds that may disrupt or highjack functionally important protein:ligand interactions. Such studies could increase the awareness of hazards posed by existing commercial chemicals at relatively low cost.     

濒危野生药材岩黄连人工栽培技术

岩黄连Corydalis saxicolaBunting为石山地区特有的多年生草本药用植物,在桂西北地区常用于消炎止痛、拔毒、治疗疥疮中毒,亦是治疗乙型肝炎、肝硬化、肝癌等疾病的中草药。目前,岩黄连的野生资源日渐减少,已无法满足生产之急需。文章总结了作者十多年来对岩黄连进行引种驯化与人工栽培繁殖试验的研究成果,对岩黄连的生态生物学特性以及种植栽培、田间管理、病虫害防治、采收加工等种植栽培过程中的关键技术进行了总结,为开展岩黄连的中药材生产质量管理规范(GAP)种植提供了重要的参考。     

清瘟败毒颗粒质量标准的研究

建立清瘟败毒颗粒剂的质量标准.采用TLC方法对处方中的黄芩、黄连进行了定性鉴别;采用HPLC方法测定黄芩苷的含量.色谱柱为KromasilTMC18;流动相为甲醇-水-磷酸(55:50:0.2),流速为1ml·min-1;检测波长280nm;进样量在0.06～0.21μg范围内线性关系良好(r=0.9996);平均回收率为100.2%,RSD=1.21%(n=6).方法准确可靠,重现性好,可作为清瘟败毒颗粒的质量控制方法.