开始发育

To better understand the roles of LsrA protein in nodulation, a series of analyses of nodules using scanning electron microscopy, genetic and biochemical approaches have been carried out. Our analyses suggest that the lsrA1 nodules contain bacteroids in the invasion and establishing zone only. The lsrA gene expression is active early in the invasion zone and activated later than bacA genes. The lost of LsrA protein dramatically reduced the expression of nifA and fixK, and completely blocked the expression of the nifH gene for nitrogenase. LsrA protein functions early in the bacteroid development and it is essential for the development nitrogen fixing bacteroids.

前期的工作中，苜蓿中华根瘤菌Rm1021中90个候选LysR基因已经被定向插入突变，并筛选在自生生长时期、共生生长时期的表型，以期寻找更多在自生状态或共生固氮中有功能的LysR转录因子。1 针对前期鉴定出的共生固氮必需的lsrA基因，我们应用了一系列扫描电子显微镜技术、生物化学、分子遗传学等方法，发现lsrA基因主要在根瘤侵染区开始表达，表达时序也在侵染阶段左右，但晚于bacA基因表达；LsrA蛋白缺失后根瘤固氮区中缺乏具有固氮能力的类菌体，nifA和fixK基因的转录水平降低，nifH基因的转录被完全阻断，因此LsrA蛋白为根瘤发育所必需，是新的根瘤发育信号传导途径成员。2 通过表型筛选我们鉴定了苜蓿中华根瘤菌的oxyR基因，并研究了它的调节特性。oxyR突变后，苜蓿中华根瘤菌对过氧化氢敏感性提高，适应性降低。

individual development from the fertilized eggs start developmentally regulated gene series started with the orderly closure of the control.

个体发育从受精卵开始就受发育调控串基因的有序启动与关闭的控制。

Drying was important for the acquisition of germinability, and drying induced precocious maturation and played some role in the transition from a development programme to a programme oriented towards germination and growth.

干燥脱水对种子萌发有重要意义，成熟脱水可以使种子由发育状态转向萌发状态，玉米种子在获得耐脱水能力之后，干燥可以使未熟玉米种子提前进入成熟状态，终止与发育有关的代谢，开始与萌发有关的代谢。

At water temperature of 16.0-17.2 ℃, the process of embryonic development could be divided into 24 stages, which were described as follow: fertilized egg at 0 min, 2-cell stage at 75 min post fertilization; myotome forming stage at 43 h PF, and hatching-out stage at 94 h PF when the accumulative temperature reached 1616.8 ℃.h, and the average size of larvae was about 3.8 mm in body length.

梭鲈胚胎发育过程可分为24期，在水温16.0~17.2℃范围内，受精75 min开始第1次卵裂，受精后43 h开始形成器官，受精后约94 h开始出膜；刚出膜的仔鱼全长平均为3.8 mm；从受精到孵化出膜总积温为1 616.8℃。h。

Specimens were examined by histological method to determine the cycle of the gonad development of this nemertean. The results showed that: The sex ratio (female: male) was about 1: 1. The sizes of mature males and females were not significantly different; females are rosy in colour and males are white, largely owing to the metamerically arranged gonads. Gonads, which were not detected in samples of autumn months, arose in December, but sexes were indistinguishable until middle January.

结果表明：扁额原细首纽虫雌雄比例约为1：1；雌雄体长、体重无显著差异；性成熟雌体通常体壁呈玫瑰红色，雄体呈白色，非繁殖季节雌雄体色无明显差异；一年有两次性腺发育，第一次12月开始出现性腺，1月可辨雌雄，3月15日达到第一次性腺发育高峰，4月15日性腺消失；第二次于4～5月开始出现性腺，6月15～30日达到高峰，9～10月性腺消失。

Using the Hprt gene as a positive control, our result suggested that both the testis tissue and the male embryos from which Sry transcription can be detected failed to yield any positive results of Xist. Female embryos at the pronucleus stage and 2-cell failed to produce any positive result of Sry and Xist too.

然后利用实验一确定的PCR条件，以Hprt为阳性对照，用巢式RT-PCR对小鼠早期胚胎进行Xist基因的转录分析，结果发现，转录Sry基因的睾丸组织以及雄性胚胎，从受精卵发育到囊胚的过程中，基本上不转录Xist基因；不转录Sry基因的雌性卵母细胞和雌性胚胎，从出现原核开始，到发育至2-细胞期的过程中，Xist基因一直不转录，但是，从4-细胞期开始，一直到孵化前囊胚阶段，雌性胚胎都转录Xist基因。

The results of study show:1. White pulp and red pulp in parenchyma of spleen of embryo can be obviously discerned after 18 days. Periarterial lymphoid sheath and ellipsoid periarterial lymphoid sheath also can be obviously discerned in spleen of 4 days chicken. T, B lymphocytes in appendix basement of embryo emerge after 20 days. It is the initial shape of cecal tonsil. Crypt structure of conjunction of esophago and stomachus glandularis form obviously at 4 days. It is the initial shape of esophago tonsil. The germinal center firstly emerges in these three organs at 14 days. With the increase of day age, the characteristic structure peripheral immune organs gradually develop mature. Spleen achieve mature at 21 days and cecal tonsil at 35 days.2. IgM~+ and IgA~+ cells in spleen of embryo emerge at 15 days. IgG~+ cell, CD3~+ and CD8~+T lymphocytes of embryo emerge at 20 days. CD3~+, CD8~+ and IgM~+ cells in cecal tonsil of embryo emerge at 20 days. However CD4~+, IgG~+ and IgA~+ cells all emerge in 1 day age chicken out of crust. CD3~+, CD4~+, CD8~+, IgM~+ and IgG~+ cells in esophago tonsil of embryo all emerge at 20 days. However IgA~+ cells emerge in 1 day age chicken out of crust.3. The amount of T, B lymphocytes in peripheral immune organs increase follow with the increase of day age, and hold an upgrade tendency. The amount of T, B lymphocytes in spleen achieved stabilization at 21 days, and in tonsil of esophago and appendix at 35 days.

研究结果表明：1、在组织结构方面，脾脏实质内的白髓与红髓在胚胎18日龄后明显可辨，4日龄雏鸡脾脏中形成明显可辨的动脉周围淋巴鞘和椭球周围淋巴鞘；盲肠基部T、B淋巴细胞在胚胎20日龄时开始出现，即初步形成盲肠扁桃体；食管与腺胃结合处在4日龄时形成明显的隐窝结构，即食管扁桃体初步形成；14日龄时，三种器官中首次出现生发中心；随着日龄的增长，外周免疫器官特征结构不断发育成熟，脾脏在21日龄时达到成熟水平，盲肠扁桃体和食管扁桃体在35日龄时达到成熟水平。2、在T、B淋巴细胞出现时间方面，脾脏中IgM~+和IgA~+细胞在胚胎15日龄时开始出现，IgG~+细胞、CD3~+和CD8~+T淋巴细胞在胚胎18日龄时出现，CD4~+细胞在胚胎20日龄时出现；盲肠扁桃体中CD3~+、CD8~+和IgM~+细胞在胚胎20日龄时开始出现，而CD4~+、IgG~+和IgA~+细胞均在雏鸡出壳后1日龄时出现；食管扁桃体中CD3~+、CD4~+、CD8~+、IgM~+和IgG~+细胞均在胚胎20日龄时开始出现，而IgA~+细胞则在雏鸡出壳后1日龄时出现。3、在T、B淋巴细胞数量变化方面，外周免疫器官中T、B淋巴细胞的数量随日龄增长，整体均呈上升趋势。

Results indicate that the best time to add FBS is in the fourth day, but in the second day, the development of parthenogenetic embryos is blocked.

结果表明，添加FBS的时间以4d开始效果较好，在胚胎发育的0d、2d开始添加不利于孤雌胚胎的发育。

No tapetal cells were formed or tapetam collapsed at very early stage in some anther chamber during the microsporogenesis; Pollen mother cells in another chamber were not developed and microspore vacuolized; Tapetum cells developed abnormally, giantized and crammed the anther chamber; Some tapetum cells developed normally, but PMCs developed abnomally, which deformed at sporogeneous stage, and then were abhensive each other and finally degenerated. Nearly no PMCs could complete the process of meiosis, and form the tetrad, leading to the failure of normal microspore development.

药室的绒毡层细胞不形成或提前解体；药室内的花粉母细胞不发育或小孢子液泡化；绒毡层细胞发育异常，出现巨型化而挤满整个药室；绒毡层细胞虽发育正常，但花粉母细胞发育异常，在造孢细胞时期即开始出现变形现象，随后发生粘连退化；绝大部分花粉母细胞不能完成正常的减数分裂过程形成四分体，导致小孢子退化。

Because of fetal growth and development and maxillofacial region as early as the third week of embryonic development began, the deciduous tooth germ in the second month of pregnancy will be begun to take shape.

因为胎儿颌面部的生长发育早在胚胎发育的第三周就开始了，乳牙的牙胚在怀孕的第二个月便开始形成。

Since historical times,England ,where the early inhabitants were Celts, has been conquered three times .

从有历史以来，英国，在此地早期居住的是凯尔特人，已经被征服了三次。

Bluetooth OBEX File Transfer Enables the sending and receiving of files on your phone via Bluetooth.

蓝牙OBEX文件移动允许经过蓝牙传送和接受文件。。。。