鸡胚肝脏液晶类脂滴冰冻蚀刻结构研究

鸡胚肝脏组织中液晶类脂滴在不同温度及不同降温速度等条件下,呈现出液晶、结晶及各向同性态,并且三相之间可以互相转变.以冰冻蚀刻复型的方法,证实鸡胚发育中肝脏类滴液晶态为迟晶型液晶,并对0℃处理后的类脂满结晶进行了观察.最后对鸡胚肝脏液晶类脂滴与低密度脂蛋白的相似性进行了讨论.     

模拟鸡胚肝脏液晶类脂滴的体外构建

鸡胚发育肝脏组织中,特定时期大量出现的液晶态类脂滴（ｌｉｑｕｉｄｃｒｙｓｔａｌｌｉｐｏｉｄｄｒｏｐｌｅｔ,ＬＣＬＤ）脂组分主要由卵磷脂、胆固醇和油烯基胆固醇酯等组成。本文中,我们以此三组分在体外进行了模拟构建,结果表明构建的类脂滴具有与ＬＣＬＤ相同的光学织构（马尔它十字）,其冰冻蚀刻复型膜的电镜观察显示其结构也为同心圆片层;构建的类脂滴与鸡胚肝ＬＣＬＤ具有相似的相变特征,经冷冻处理也形成结晶,并在室温下保持这种状态,该结晶的冰刻结构也与胚肝ＬＣＬＤ类似     

鸡胚发育中肝脏类脂滴液晶态结构的研究

本文应用小角x射线衍射法,辅之以差热分析(DTA)和偏光显微镜法,研究了鸡胚肝脏中的液晶态类脂滴的结构和相变特性.结果表明:肝脏类脂滴是由同心的片层构成的球形颗粒,片层厚度为37(?);在室温及不高于其生理温度的范围内,处于片层状液晶态,在37～41℃,则转变成各向同性液态.并认为此片层状液晶态可能具有特殊的生物功能.     

几种初生鸟类（家禽）肝脏液晶类脂滴的比较研究

本文中,我们观察到初生鸭、山鸡、乌鸡、鹌鹑和鸽的肝脏组织中液晶类脂滴（ＬＣＬＤ）分布于肝索上肝细胞内,血窦中少有;ＬＣＬＤ液晶态重复间距依次分别为３６．８Ａ,３７．４Ａ,３７．６Ａ,３７．８Ａ和３８．４Ａ。经冷冻处理室温下ＬＣＬＤ均以结晶态存在;它们的Ｘ射线衍射特性均与其对应的脂类提取物结晶的衍射特性一致。衍射分析表明,初生鸭、山鸡、乌鸡和鹌鹑与鸡胚肝ＬＣＬＤ结晶为同一类晶相,而初生鸽肝ＬＣＬＤ结     

尼罗罗非鱼Tilapia nilotica卵巢发育过程中液晶态类脂滴组织化学初步研究

我们研究了尼罗罗非鱼卵巢中的液晶态。用偏光显微镜观察到在第3和第4时相卵母细胞的胞质、滤泡细胞和部份间质区存在着双折射和多种形式的“马尔它十字”。电子显微镜观察到这些“马尔它十字”小滴是多层的膜结构。根据这些小滴的性质和结构,将其归属于溶致性液晶(lyotropic liquid crystal)的片层相(lamellar phase),即纯净相(neat phase)(孙建民1981)。     

苯及丙酮对磷脂酰乙醇胺液晶态结构的影响

用小角 X 射线散射(SAXS)法研究了苯、丙酮对磷脂酰乙醇胺(PE)液晶态结构的影响.实验结果表明:苯能使 PE 液晶态先从片层相解束变成立方相.然后再诱导立方相变成六角形 H_Ⅱ相,最后促使六角形 H_Ⅱ相解束变成液态.在解束相变中出现了红移现象.丙酮也有使 PE 液晶态先从片层相解束变成立方相,在解束相变中也出现红移现象,但再诱导立方相变成六角形 H_Ⅱ相之后,不是促使其变成液相,而是将其稳定在六角形 H_Ⅱ相.     

鸡胚早期神经系统发育中凋亡细胞的分布研究

研究鸡胚18S（Stage）神经系统发育中凋亡细胞的分布及其生物学意义。采用HNK－1和TUNEL免疫组化双染及改变切片方向的方法观察了神经管和神经嵴的凋亡细胞,结果显示：凋亡的细胞在间隔10张横向切片上呈非均匀分布,但在矢状切面凋亡细胞有节段性分布趋势。体节处连续神经嵴没有发现凋亡细胞,而体节与体节之间神经嵴迁离神经管呈游离状并有凋亡细胞,神经管腹侧面体节处间充质细胞呈现细胞凋亡节段性分布。结果表明：鸡胚早期神经系统发育中选择性发生细胞凋亡作用。     

鸡胚发育中染色体长度的变化及螺旋结构

对孵育3-72小时家鸡胚胎染色体长度及螺旋结构进行了比较研究,同时还考察了染色体DNA含量的变化。结果表明：(1)家鸡染色体的最高一级结构是螺旋结构。(2）随胚胎发育的进展,染色体绝对长度逐渐缩短。(3）伴随染色体的缩短,其螺旋数目亦相应地减少,而螺旋直径却有一定程度增加。(4）每个中期板的染色体DNA含量并不随发育进展而变化。本文还讨论了发育中染色体缩短与螺旋结构间的相互关系。     

鸡胚发育后期心电图的无损测定及心率变化

目的：测量鸣胚发育后期心电图,测定鸡胚发育后期心率及其变化.方法：利用壳膜外电极测量鸡胚心电图,根据RR间期计算鸡胚心率。结果：引出了具有较为清晰Q波、R波（振幅在8—20μV波动）、S波的鸡胚心电图。鸡胚的QRs间期在发育后期无明显变化,心率在D14～D20早期的心率变化较小,在D20后期和D21显著增加（P〈0．01）。结论：建立了壳膜外记录鸡胚心电图的方法,鸡胚在啄壳期心率显著增加.     

鸡胚视网膜基膜的免疫电镜的研究

扫描电镜观察到鸡胚视网膜基膜(RBM)上的菊花样结构,经免疫胶体金透射电镜证实为Müller胶质细胞的末端足,层粘连蛋白(laminin)分布在末端足的辐射臂及其周围的基膜上。培养的视网膜细胞,其神经纤维在RBM伸长,收缩了的Müller细胞末端足呈球状颗粒分布在神经纤维及其生长锥的上面和侧面。推测分布在Müller细胞末端足的辐射臂及其周围基膜上的层粘连蛋白在体内可能与神经纤维生长的导向有关。     

多烯脂肪酸对磷脂胆固醇液晶态结构影响机理

用小角Ｘ 射线散射法、３１Ｐ 核磁共振技术和扫描隧道显微镜技术,对多烯脂肪酸多相脂质体的液晶态结构进行了研究。实验结果表明：胆固醇、多烯脂肪酸、非离子表面活性剂均对ＰＥ 脂质体的液晶态结构有明显的影响。在含有高效分散剂的磷酸缓冲溶液中制成的液晶态油酸多相脂质体和亚油酸多相脂质体均由片层六角相和片层立方相组成, 而蓖麻酸多相脂质体由立方六角相组成。     

西瓜基因转化及其转基因植株再生的研究

西瓜味甜汁多,营养丰富,能消暑、解渴,是夏季重要水果。主要危害是马铃薯Y病毒组(Potyviring group)的西瓜花叶病毒一号(WMV-Ⅰ)和西瓜花叶病毒二号(WMV-Ⅱ)。WMV-Ⅰ和WMV-Ⅱ发病严重,农药防治效果差且存在农药残留问题。目前尚未选育出抗病新品种。近年来,国内外广泛采用植物基因工程方法来选育抗病毒的良种,其中利用外壳蛋     

人体胆汁液晶光学性质的研究

在单偏光和正交偏光显微镜下对人体胆汁液晶的光学性质进行研究。结果表明：人体胆汁中的液晶以球形的微粒分散于胆汁中,其多色性、吸收性不明显,但边缘和贝克线很清楚,折射率大于胆汁折射率;在正交偏光镜下,呈现出特殊的干涉图样,载物台在３６０度转动过程中呈现出四次消光现象,光性符号是单轴正性的;干涉色级是一级灰白,双折射率△ｎ＝０．０１１－０．０１５。     

THE METABOLISM OF TISSUE CULTURES : I. PRELIMINARY STUDIES ON CHICK EMBRYO

1. The metabolism of chick embryo tissues has been followed by analysis of the culture media after various periods of incubation in roller bottles. 2. The initial rate of glucose utilization is increased by increasing glucose in the medium from 100 to 500 mg. per cent. Total glucose used can be increased in the same way or by daily addition of small amounts. Glucose is used in greatest amount when the medium containing 100 mg. per cent is replaced daily. 3. Although glucose consumption appears necessary for survival of cultures it may be used at a rate far in excess of that required for life and maximal growth. Complete blocking of mitosis by colchicine does not alter the rate of glucose utilization. 4. Proteolytic activity of the cultures is shown by an increase in the amino nitrogen of the peptone medium after incubation with tissue. 5. Utilization of nitrogen from an amino acid medium is shown by a decrease in the amino nitrogen of this medium. Cells obtaining their nitrogen from amino acids proliferate as rapidly as those grown in a medium identical except for the substitution of peptone, but the cell type is markedly different, in that embryo muscle forms cells resembling regenerating adult muscle. 6. Lactic acid was formed in both the presence and absence of glucose. Its formation increased with increased glucose utilization. There is some evidence that lactate may be utilized, and that it favors growth in the absence of glucose. 7. Added pyruvate was rapidly metabolized by the tissues. It, too, favors growth slightly in the absence of glucose.     

鸡菌的液体培养及其多糖物质研究

采用不同的液体培养基,探索了鸡堆放(土从)菌(Termitomyces albuminosus)人工培养的最适条件,多糖形成的动态变化,并对鸡(土从)多糖进行了分离、纯化,及其免疫活性测定。结果表明:鸡(土从)菌从碳源玉米淀粉,氮源花生蛋白,生长因子麸皮浸汁,pH4.7,25℃为最适生长条件;Sephadex-G100分离多糖出现两个峰;鸡(土从)多糖作为刺激原对人淋巴细胞转化有促进作用。     

THE EFFECTS OF 5-BROMODEOXYURIDINE ON YOLK SAC ERYTHROPOIESIS IN THE CHICK EMBRYO

The effects of the thymidine analog, 5-bromodeoxyuridine (BUdR), on the formation of red cells in the yolk sac of the chick embryo were examined. The prospective area opaca vasculosa from a definitive primitive streak embryo was excised, disaggregated, and deposited into a cell clump, and the cell clump was placed in organ culture. Hemoglobin synthesis is detectable after about 16 hr in culture. The formation of erythropoietic foci and incorporation of ⁵⁵Fe into heme were used to measure the extent of erythropoiesis. Exposure to 40 µg/ml of BUdR within 6 hr after explantation almost completely eliminated red cell formation; subsequent transfer to thymidine medium showed that the inhibition was reversible, and there was no histological evidence of analog toxicity. Between 6 and 12 hr after initiation of organ culture, the tissue became completely refractory to BUdR. DNA synthesis, as monitored by thymidine-³H and BUdR-³H pulses, was extensive both during and after the period of BUdR sensitivity. Hence, during both BUdR sensitive and insensitive periods the analog was incorporated into DNA of cells which had not yet synthesized hemoglobin. It is proposed that between 6 and 12 hr a crucial regulatory event for terminal differentiation is perturbed by the presence of BUdR in the chromosomes.