促凋亡基因(Bad)在卵泡期绵羊生殖器官中的表达

以卵泡期小尾寒羊和萨福克羊为研究对象,采用免疫组织化学技术,对促凋亡基因(Bad)在生殖器官卵巢、输卵管和子宫中的表达与定位进行初步研究。结果表明,在卵巢组织中Bad基因在原始卵泡、初级卵泡和次级卵泡中呈中度着染,在三级卵泡中呈轻度着染,阳性细胞在卵泡上皮细胞和颗粒细胞中分散分布,呈轻度着染;输卵管上皮分泌细胞和部分纤毛细胞胞质中见Bad基因中等强度表达,输卵管壶腹部上皮中,Bad基因多表达于分泌细胞,纤毛细胞中有部分呈阳性且强度弱,宫管结合部、峡部和壶腹部Bad基因阳性细胞染色强度弱,均呈中度着染;子宫内膜子叶和基质中的阳性细胞数量极少,阳性细胞呈轻度着色。利用计算机图像分析技术测量小尾寒羊和萨福克羊生殖器官各组织细胞中Bad基因表达的阳性细胞率和平均光密度,结果Bad基因在这2品种绵羊组织中的表达规律大体相似,但也存在一些明显的差异:萨福克羊三级卵泡颗粒细胞Bad基因阳性细胞率显著高于小尾寒羊(P0.01);萨福克羊三级卵泡和成熟卵泡膜细胞Bad基因阳性细胞率和平均光密度均显著高于小尾寒羊(P0.01);萨福克羊子宫内膜腺体卵泡期Bad基因阳性细胞平均光密度显著高于小尾寒羊(P0.01);由此表明,小尾寒羊和萨福克羊卵泡期生殖器官中细胞凋亡的差异与Bad基因表达的差异,可能是造成两者繁殖力高低差异的基础。     

不同来源木聚糖酶对黄羽肉鸡小肠绒毛形态结构和黏膜生长抑素mRNA表达的影响

本文旨在比较研究小麦型饲粮中添加不同来源木聚糖酶对黄羽肉鸡小肠绒毛形态结构和黏膜生长抑素(SS)mRNA表达的影响.选择22日龄、体重相近的健康黄羽肉鸡375羽,随机分成3个组,每组5个重复,每重复25羽.对照组饲喂小麦型基础饲粮,试验Ⅰ和Ⅱ组分别饲喂在基础日粮中添加250 mL/t真菌性和细菌性木聚糖酶的试验饲粮,试...     

The mutagenesis of a type IV secretion system locus of Piscirickettsia salmonis leads to the attenuation of the pathogen in Atlantic salmon,Salmo salar

Piscirickettsiosis is a threatening infectious disease for the salmon industry, due to it being responsible for significant economic losses. The control of outbreaks also poses considerable environmental challenges. Despite Piscirickettsia salmonis having been discovered as the aetiological agent of the disease more than 25 years ago, its pathogenicity remains poorly understood. Among virulence factors identified so far, type four secretion systems (T4SS) seem to play a key role during the infection caused by the bacterium. We report here the genetic manipulation of P. salmonis by means of the transference of plasmid DNA in mating assays. An insertion cassette was engineered for targeting the icmB gene, which encodes a putative T4SS‐ATPase and is carried by one of the chromosomal T4SS clusters found within the genome of P. salmonis PM15972A1, a virulent representative of the EM‐90‐like strain. The molecular characterization of the resulting mutant strain demonstrated that the insertion interrupted the target gene. Further in vitro testing of the icmB mutant showed a dramatic drop in infectivity as tested in CHSE‐214 cells, which is in agreement with its attenuated behaviour observed in vivo. Altogether, our results demonstrate that, similar to other facultative intracellular pathogens, P. salmonis’ virulence relies on an intact T4SS.     

生长抑素(SS)与硫氧还原蛋白(Thioredoxin)相融合生成的2种基因工程化融合蛋白SS-N/X和SS-N/S的表达特性

对基因工程化生长抑素（somatostatin,SS)-硫氧还原蛋白（Thioredoxin)融合蛋白SS－N／X和SS－N／S的表达产量、水溶性、Triton X-100对SS融合蛋白水溶性的影响、包涵体的溶解和复性特点以及SS的抗原性与免疫原性等特性进行了研究。结果显示，在30℃的低温下用IPTG诱导表达，SS－N／X融合蛋白主要以可溶性形式存在，占75．8％，色涵体仅占24．2％；而SS－N／S融合蛋白则主要以包涵体的形式存在，占81．1％，可溶性蛋白仅占18．9％；32C载体（pEG-32C)蛋白则居二者之间，可溶性蛋白与包涵体大约等比例出现。SS－N／S在低温下诱导可超量表达SS融合蛋白，其表达量约占菌体总蛋白的40．94％。0．5％ Triton X-100对融合蛋白的不溶性有非常显著的影响，几乎可使所有的SS－N／X融合蛋白和大部分SS－N／S融合蛋白及32C硫氧还原蛋白变成水溶性的。32C硫氧还原蛋白包涵体在尿素中的溶解度明显高于SS－N／S包涵体，2mol/L尿素可使近一半的32C硫氧还原蛋白包涵体溶解，而SS－N／S包涵体只有27．5％溶解；但在5mol/L尿素时，两者均可基本全部变为可溶性的。在SS融合蛋白包涵体溶解时加入还原剂二硫苏糖醇，可明显降低SS的抗原性。SS融合蛋白（水溶性融合蛋白和复性后的包涵体）具有良好的SS抗原性和免疫原性。由SS融合蛋白与弗氏不完全佐剂制成试验用疫苗，免疫BALB／c小鼠、仔猪和羔羊等动物，可显著提高免疫动物的增重。     

玉米淀粉合成酶SSⅡa启动子的克隆及功能分析

【目的】克隆玉米Zea mays淀粉合成酶SSⅡa启动子,并分析其功能,为进一步研究和应用SSⅡa启动子奠定基础。【方法】通过NCBI上公布的玉米基因组序列,在网站Maize GDB上BLAST查找到SSⅡa 5'侧翼序列,利用PCR方法从玉米B73中克隆SSⅡa启动子;通过Plant Care在线分析启动子顺式作用元件,用特异性引物分别克隆出长度为1 407、867、633、483和365 bp的片段,与植物表达载体p CAMBIA3301连接,构建5种5'缺失体的植物表达载体,命名为P1、P2、P3、P4和P5。用农杆菌介导法转化拟南芥Arabidopsis thaliana,获得转基因拟南芥。【结果】以玉米B73基因组DNA为模板,用特异性引物SSⅡa F/SSⅡaR进行扩增,得到2 526 bp序列;除草剂筛选的阳性拟南芥植株PCR验证均检测出gus基因;GUS组织化学分析表明,5种类型启动子构建的表达载体在成熟期叶片、果荚中均显蓝色;gus基因定量分析表明,成熟期5种转基因拟南芥叶片中,gus基因表达量P1最高,其他基本一致;种子中gus基因表达量P1和P2相近,且高于P3、P4和P5。【结论】成功克隆玉米SSⅡa启动子;构建的5种SSⅡa启动子缺失体表达载体在转基因拟南芥中均具有活性,长度为1 407 bp(P1)和867 bp(P2)的启动子具有胚乳特异性。     

H9N2亚型禽流感病毒传播途径特性的比较及其表面基因序列分析

选择中国大陆最早分离的H9N2亚型禽流感病毒(avian influenza virus,AIV)A/Chicken/Guangdong/SS/94(H9N2)(缩写为SS株)和1998年大流行时期分离的H9N2亚型AIVA/Chicken/Shanghai/F/98(H9N2)(缩写为F株)为研究对象,对其在SPF鸡体内的复制能力和传播途径特性比较后发现,F株在4周龄SPF鸡气管中的复制能力高于SS株,F株可以经气溶胶传播途径传播,SS株不能经气溶胶传播途径传播;利用反转录-聚合酶链反应(RT-PCR)方法获取F株和SS株的HA和NA基因的cDNA,序列分析得知,F株和SS株的HA和NA基因的同源性分别是96.6%和98.1%;HA基因的裂解位点氨基酸序列都是PARSSR↓GL,但有5个氨基酸的差异,即166位N(F)→D(SS)、198位A(F)→V(SS)、217位V(F)→I(SS)、335位G(F)→R(SS)、504位L(F)→S(SS);2株病毒的NA基因在63~65位都存在氨基酸缺失,但在NA基因红细胞吸附位点的氨基酸序列不同,分别是IKKDSRSG(F)和IKEDLRSG(SS)。F株和SS株的传播特性差异是否与其表面基因序列有关,有待进一步研究。     

Rootstock influence on ‘delicious’ and ‘golden delicious’ apple fruit quality at harvest and after storage

The influence of 9 rootstocks (M2, M7, M25, M26, MM104, MM106, MM109, MM111 and seedling) on fruit quality at harvest and after storage of ‘Wellspur Delicious’ (WS) and ‘Goldspur’ (GS), and of 3 rootstocks (M7, M26 and MM106) on fruit quality of ‘Red King Delicious’ (RK) and ‘Golden Delicious’ (GD) apple (Malus domestica Borkh.) was evaluated during a 4-year period. Fruits from trees on M26 were larger, developed earlier color and soluble solids (SS), and maintained higher levels of acidity (at harvest and during storage) in comparison with other rootstocks. Fruit from trees on M2 tended to have high SS. Fruit color from trees on MM104, MM106 and MM109 tended to be comparatively poor. There were significant rootstock effects on SS, starch, acidity, color, circumference, weight and box size.     

Effects of light,macronutrients, and sucrose on germination and development of the endangered fern Adiantum reniforme var. sinense (Adiantaceae)

Effects of light, macronutrients strength of Murashige and Skoog (MS) (1962), and sucrose in the culture medium on spore germination and gametophyte development of the endangered fern Adiantum reniforme var. sinense were investigated. The presence of light was found to be essential for both spore germination and gametophyte growth. Moreover, a medium consisting of 1/4 MS with 15 g/l sucrose was optimal for spore germination and early gametophyte development; whereas, MS medium with 30 g/l sucrose was optimal for further gametophyte development. Increasing amounts of sucrose (45–60 g/l) in the medium delayed gametophyte growth and development. Additionally, sporophyte formation and early growth of gametophytes in a medium consisting of clay and peat (v/v = 1:2) was higher than those in a medium consisting of pure river sand. These findings indicated that requirements for nutrients for spore germination and early gametophyte development of A. reniforme var. sinese were relatively low, but these increased with further gametophyte development, formation and growth of sporophytes.     

七彩山鸡胃肠道生长抑素细胞的免疫组织化学定位

[目的]应用生长抑素（somatostatin,SS）抗血清研究七彩山鸡（Phasianus colchicas）胃肠道SS免疫活性细胞的分布密度和形态,并探讨其分布型的成因及细胞形态与功能的关系。[方法]采用免疫组织化学方法进行试验。[结果]SS细胞在腺胃及十二指肠以下都有分布。在回肠分布密度最高,空肠和十二指肠较高,盲肠和腺胃次之,直肠很少。SS细胞的型态多样,呈圆形、椭圆形、锥体形等,主要分布于胃肠固有膜、黏膜上皮细胞之间、黏膜上皮细胞基部、腺泡上皮细胞之间。[结论]七彩山鸡胃肠道SS细胞分布型的形成与各部位消化功能有关,根据形态,认为七彩山鸡胃肠道SS细胞具有内、外分泌两种功能。