Kinetic measurements of cell surface E-selectin/carbohydrate ligand interactions

Selectin/ligand interactions initiate the multistep adhesion and signaling cascades in the recruitment of leukocytes from circulation to inflamed tissues and may also play a role in tumor metastasis. Kinetic properties of these interactions are essential determinants governing blood-borne cells' tethering to and rolling on the vessel wall. Extending our recently developed micropipette method, we have measured the kinetic rates of E-selectin/ligand interactions. Red cells coated with an E-selectin construct were allowed to bind HL-60 or Colo-205 cells bearing carbohydrate ligands. Specific adhesions were observed to occur at isolated points, the frequency of which followed a Poisson distribution. These point attachments were formed at the same rate with both the HL-60 and Colo-205 cells (0.14 +/- 0.04 and 0.13 +/- 0.03 mum(2) s(-1) per unit density of E-selectin, respectively) but dissociated from the former at a rate twice as fast as did from the latter (0.92 +/- 0.23 and 0.44 +/- 0.10 s(-1), respectively). The reverse rates agree well with those measured by the flow chamber. The forward rates are orders of magnitude higher than those of Fc gamma receptors interacting with IgG measured under similar conditions, consistent with the rapid kinetics requirement for the function of E-selectin/ligand binding, which is to capture leukocytes on endothelial surfaces from flow.

二萜生物碱植物的化学成分研究

本论文由三个部分组成。第一部分是综述性文章-天然C19-二萜生物碱的结构及其核磁共振波谱。这篇综述参考160余篇文献，将迄今为止发表的230余个天然C19-二萜生物碱按其结构和波谱特征，分为10个类型。重点叙述了每个类型的结构和核磁共振波谱，对一些立体构型与13C-NMR化学位移的关系进行了讨论。最后以表格的形式报导了每个天然C19-二萜生物碱的结构及其植物来源，并把其中170余个收集到的13C-NMR化学位移数据整理成表，作为手册，对鉴定此类化合物大有帮助。第二部分是实验论文--弯啄乌头的化学成分研究。重点报导了弯啄乌头(Aconitum campylorrhynchun Hand-Nazz.)中分离到的一个新生物碱--8-乙酰都啦碱(8-acetyldolaconine)的结构鉴定，并根据DEPT、COSY、COLO等对1H-NMR和13C-NMR的所有信号归属都进行了指定。通过各种图谱还发现这个生物碱的A环同时存在着椅式和船式两种构象导购体。另外还报导了从同一植物的生物碱部分分离到的两个二萜生物碱，它们都是嘟啦碱和aconosine.在非生物碱部分还分离到三个化合物，经鉴定证明是β-谷甾醇、棕榈酸和香豆酸。第三部分也是实验论文--展毛翠雀花中生物碱成分的研究。报导了从展毛翠雀花(Delphinium Kamaonense Var.glabrescens W. T. Wang)中初步分离到的两个生物碱。经IR、NS、1H-NMR和13C-NMR等方法确定结构，证明其中一个是新化合物，命名为展毛翠雀碱(glabredelphinine)。另外一个是前几年发现的二萜生物碱tatsiensine。这两个化合物的A环上都有碳-碳不饱和键，这在天然C19-二萜生物碱中还比较少见。This master's thesis consists of three parts. The first part is a review: The relationship between the chemical structures of natural C19-diterpene alkaloids and their NMR chemical shift data. The C19-diterpene alkaloids were divided into ten types according to their structures and NMR data. Some relationaships between configuration and NMR chemical shift have been discussed. The structures and distributions of more than 230 known C19-diterpene alkaloids and the assignments of 13C-NMR data of the 170 alkaloids of them were listed in tables. The second part is an experimental paper, Studies on the chemical constituents of Aconitum campylorrhynchum. Six compounds were isolated from the roots of title plant. One of them is a new alkaloid. It has been elucidaled as 8-acetyldolaconine by means of IR, MS, 1H-NMR,13C-NMR,DEPT,COSY,COLOC and on the basis of identification with aconosine by saponification. Other five compounds were idenfified as dolaconine, aconosine,β-sitosterol, palmitic acid and p-coumaric acid. The third part is also experimental paper: The alkaloids of Delphinium Kamaonense var.glabrescens. Two alkaloids were isolated from the roots of title plant. One of them, C22H22O6N,m.p.201-3℃,named glabredelphinine, was proved to be a new compound. Its structure has been established as 2(3)-dehydro-6-demethyl-18-delcosine by means of IR, MS, 1H-NMR and 13C-NMR.The other one was identified as tatsiensine by comparising of IR, MS, 1H-NMR and 13C-NMR data with that from the literatute.

Spin and spin-isospin instabilities and Landau parameters of Skyrme interactions with tensor correlations

The Landau parameters of Skyrme interactions in the spin and spin-isospin channels are studied using various Skyrme effective interactions with and without tensor correlations. We focus on the role of the tensor terms on the spin and spin-isospin instabilities that can occur in nuclear matter above saturation density. We point out that these instabilities are realized in nuclear matter at the critical density of about two times the saturation density for all the adopted parameter sets. The critical density is shown to be very much dependent not only on the choice of the Skyrme parameter set, but also on the inclusion of the tensor terms.

Constraints on the symmetry energy and neutron skins from pygmy resonances in Ni-68 and Sn-132

Correlations between the behavior of the nuclear symmetry energy, the neutron skins, and the percentage of energy-weighted sum rule (EWSR) exhausted by the pygmy dipole resonance (PDR) in Ni-68 and Sn-132 are investigated by using different random phase approximation (RPA) models for the dipole response, based on a representative set of Skyrme effective forces plus meson-exchange effective Lagrangians. A comparison with the experimental data has allowed us to constrain the value of the derivative of the symmetry energy at saturation. The neutron skin radius is deduced under this constraint.

三种海水经济鱼类早期发育生物学的研究

海水经济鱼类的养殖在我国已经形成第四次海水养殖浪潮，经济效益显著，有力地推动了我国海水养殖的产业结构调整和可持续发展。然而在海水养殖发展过程中也存在着诸多问题，尤其是早期发育阶段的高死亡率，严重制约了我国海水养殖产业的稳定和健康发展。 海水鱼类养殖的关键为高质量，高存活率苗种的生产和培育，由于鱼类种类繁多，生物多样性丰富，对应实际的繁育技术，尤其是新品种的开发，必须要做出相应的调整。这就要求我们必须对每一种鱼类早期发育有所了解，并将形态和组织上的数据用于指导生产。 本文通过显微观察和组织学研究，主要描述和研究了我国北方三种重要的海水经济鱼类(条斑星鲽、杂交鲆、条石鲷)的早期发育生物学，并结合实际生产进一步阐明关键期的产生原因，机理以及采用相应的对策。具体结果如下： 1.条斑星鲽：作为冷温性鲆鲽鱼类，条斑星鲽早期发育过程的特征主要有： ① 条斑星鲽受精卵无油球，卵子呈半浮性；不同步卵裂现象提前，发生在第三次卵裂；卵裂期裂球大小差异大。孵化过程较长，在水温8 ± 0.3℃，盐度33的条件下，经9 d孵化。条斑星鲽胚胎发育的不同时期对温度的敏感性不同，其中原肠期对温度比较敏感。 ②在8-10℃，盐度33的条件下，8-9 dph开口摄食。且开口时，其吻前端出现有一点状黑褐色素，构成了条斑星鲽仔鱼“开口期”的重要标志。卵黄囊于消失。在后期仔鱼末期，背鳍和臀鳍上形成特有的黑褐色条斑带。 ③杯状细胞首先出现在咽腔后部和食道前段，胃腺和幽门盲囊出现于29 dph，变态期始于30dph。在条斑星鲽早期发育过程中，观察到其直肠粘膜层细胞质出现大量嗜伊红颗粒，为仔鱼肠道上皮吸收的蛋白质。 ④首先淋巴化的免疫器官是头肾，然后是胸腺和脾脏，这与大部分硬骨鱼类不同。条斑星鲽除头肾和脾脏外，胸腺实质也形成MMCs。其中以脾脏形成MMCs最为丰富，形态多样。 2. 杂交鲆：为同属的牙鲆和夏鲆间的远缘杂交种，其发育过程的特点为： ① 在温度为15.4～16.0℃，杂交鲆胚胎从受精到孵化所需的时间为76 h左右，胚孔关闭前期，胚胎先出现视囊及克氏囊，而后形成体节。孵出前胚体在卵膜内环绕不到1周。 ② 孵化后消失。杂交鲆群体变态间隔长(34-60 dph)，且变态高峰期出现的冠状幼鳍不明显(与母本牙鲆相比)，数量为7-8根。 ③组织学观察发现，其消化系统中胃腺出现较晚，且胃腺发育过程缓慢(与母本牙鲆相比)。甲状腺滤泡增生不明显，颜色较浅，数量较少。杂交鲆在早期发育过程中，并没有出现鳔原基。 3. 条石鲷作为岩礁性的暖水性鱼类，早期发育过程也较为特殊，包括外形以及内部的器官结构。主要特点有： ① 受精卵：受精卵卵黄上具有龟裂结构，为鱼卵的分类特征之一。 ② 初孵仔鱼：初孵仔鱼背鳍膜上的黑色素，从体背面向背鳍膜边缘移动，到3dph仔鱼基本消失，此为本种仔鱼发育所特有的特点。 ③ 后期仔鱼和稚鱼：肠道肌肉层加厚明显，仔稚鱼胃肠排空率急剧上升，死亡率增加，通过改善常规的投饵方式部分解决了这个死亡高峰的问题。在幼鱼初期，牙齿融合为骨喙，为石鲷科鱼类的特征。 ④胸腺上皮分泌细胞：类似的现象同样在虹鳟鱼中发现，但是虹鳟鱼胸腺上皮分泌细胞不如条石鲷的丰富，同样也不如条石鲷的排列整齐，而是零星分布在胸腺上皮与咽腔接触的表面。除了正常的造血器官—脾脏和头肾外，肝脏、胰腺和鳔等多种组织等也出现MMCs，此现象在硬骨鱼类不多见，一般发生在软骨鱼类。