辽宁黑山恐龙蛋──长形蛋类新分子的发现及其意义

辽宁西部黑山县下白垩统发现我国最早的恐龙蛋壳化石,属长形蛋类,取名常氏黑山蛋（新属新种）（Ｈｅｉｓｈａｎｏｏｌｉｔｈｕｓ ｃｈａｏｇｉｉ　ｏｏｇｅｎ ｅｔ ｏｏｓｐ ｎｏｖ）。该新属种蛋壳表面具密集的细瘤状纹饰,局部相邻的两个或数个细瘤联结成链条状细脊,锥体层极薄,锥体层与柱状层之比约为１：７。根据埋藏情况来看,产蛋恐龙生活在湿热、植被茂盛的河湖沼泽附近的生态环境。     

A Rare Lysozyme Crystal Form Solved Using Highly Redundant Multiple Electron Diffraction Datasets from Micron-Sized Crystals

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Analysis of Global and Site-Specific Radiation Damage in Cryo-EM

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Collection of Continuous Rotation MicroED Data from Ion Beam-Milled Crystals of Any Size

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Charting the surfaces of the purple membrane

The preponderance of structural data of the purple membrane from X-ray diffraction (XRD), electron crystallography (EC), and atomic force microscopy (AFM) allows us to ask questions about the structure of bacteriorhodopsin itself, as well as about the information derived from the different techniques. The transmembrane helices of bacteriorhodopsin are quite similar in both EC and XRD models. In contrast, the loops at the surfaces of the purple membrane show the highest variability between the atomic models, comparable to the height variance measured by AFM. The excellent agreement of the AFM topographs with the atomic models from XRD builds confidence in the results. Small technical difficulties in EC lead to poorer resolution of the loop structures, although the combination of atomic models with AFM surfaces allows clear interpretation of the extent and flexibility of the loop structures. While XRD remains the premier technique to determine very-high-resolution structures, EC offers a method to determine loop structures unhindered by three-dimensional crystal contacts, and AFM provides information about surface structures and their flexibility under physiological conditions.     

Taphonomy and taxonomy of a vertebrate microsite in the mid-Cretaceous (Albian–Cenomanian) Blackleaf Formation,southwest Montana

The vertebrate fauna of the Cretaceous Blackleaf Formation of southwest Montana remains largely undocumented. A microsite (BL1) discovered in the Flood Member in the Lima Peaks area, Montana, consists of a green siltstone and yields taxa previously unreported from the formation, including several dinosaurs: a hypsilophodont, dromaeosaurid, tyrannosauroid, hadrosaurid and an ankylosaurian. Non-dinosaurian taxa include goniopholidid and Bernissartia crocodilians; Glyptops, cf. chelydrid and other turtles and at least two neopterygiian fish. This diversity corresponds well with the fluvial–deltaic–estuarine environment interpreted for the uppermost unit of the Flood Member. Taphonomic data and sedimentologic relationships suggest that this assemblage represents a floodplain depression accumulation. Comparisons with contemporaneous faunas from around the Western Interior of the USA suggest a remarkably consistent faunal makeup, at least at the family level, existed across western North America in the mid-Cretaceous.     

Qualitative Analyses of Polishing and Precoating FIB Milled Crystals for MicroED

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藏马鸡卵壳的扫描电镜观察

利用扫描电镜对我国特有珍禽──藏马鸡的卵壳进行了超微结构观察。电镜下显示：藏马鸡卵壳从内向外由壳膜层、锥体层、海绵层和表层等组成。壳膜层内层致密、含少量纤维,外层为纵横交错成网状的纤维结构,锥体层由许多乳头状突起密集排列组成,海绵层为似沉积岩层的层状结构,表层在卵壳最外面,上由具保护性的透明蛋白质薄膜覆盖。与同属的褐马鸡的卵壳进行比较,其超微结构存在差异。     

Improved hatching for in vitro quail embryo culture using surrogate eggshell and artificial vessel

The establishment of avian embryonic culture is important both for the analysis of the developmental process and the establishment of transgenic chickens that produce useful biological materials in eggs. However, the hatchability of cultured embryos has been ∼50%. We identified that the low rate of hatchability of cultured embryos was caused by limited oxygen and calcium availability. In quail embryo culture using chicken eggshell as a culture vessel,viability in the middle stage of culture was improved and 30% of embryos were hatched by oxygen enrichment. Furthermore, hatchability increased to 80% by supplementation with calcium lactate in addition to oxygen aeration. In the present study, a fully artificial vessel for quail embryo culture was designed using a gas-permeable Teflon membrane. By the addition of fine eggshell powder and calcium lactate, quail embryos grew and developed normally, and 43% of embryos hatched. Although the hatchability was lower than that of cultures using a surrogate eggshell, we achieved in hatching an avian embryo using a fully artificial vessel.     

Progress towards structural elucidation of Photosystem II

In recent years Photosystem II, and in particular the oxygen evolving component of the enzyme, have been the subject of intense biochemical and biophysical analysis. To date no high resolution structural model of the complex has been produced. As a consequence unambiguous interpretation of much experimental data has proven difficult, leading to a lack of consensus over many basic questions regarding the mechanisms involved, the oligomerization state of the enzyme in vivo and even the exact biochemical composition.This review is a summary of the progress towards the production of a structural model of PS II-derived from either X-ray crystallography or electron microscopy based techniques-and the current opinions, which have arisen from these structural analyses, on the structural topology and assemblage of the various subunits that constitute the complex.Abbreviations C₁₂-M dodecyl maltoside - CP chlorophyll protein - cyt b-559 cytochrome b-559 - DMPC dimyristoyl phosphatidyl choline - EC electron crystallography - EM electron microscopy - LHC II light harvesting complex II - OEC oxygen evolving complex - OG octyl--glucopyranoside - PS I Photosystem I - PS II Photosystem II - Tris N-tris (hydroxymethyl) amino ethane