rpoS对鳗弧菌MHK3株Hcp表达和杀菌能力的影响

溶血素共调节蛋白(Hcp)的合成和分泌是六型分泌系统(T6SS)行使功能的重要特征。RNA聚合酶的σ亚基RpoS参与调节细菌的生长和应激反应。为了探究RpoS对鳗弧菌(Vibrio anguillarum) T6SS的调控作用,本研究构建了MHK3?rpoS突变株,检测了部分表型特征的变化;利用lacZ半乳糖苷酶报告基因检测了突变株hcp1和hcp2在转录水平的变化;进行Western blot并定量分析突变株Hcp在翻译水平的变化;并通过细菌拮抗实验检测了突变株杀菌能力的变化。结果显示,MHK3?rpoS突变株的生长情况、泳动性、明胶酶活性及酪蛋白酶活性与MHK3野生株相比无显著差异(P>0.05),而平台早期的菌膜形成能力有显著上升(P<0.05);在各生长时期,MHK3?rpoS的hcp1和hcp2在转录水平的表达量均较MHK3有显著上升(P<0.01),最高时分别为MHK3的1.79倍和1.94倍;在翻译水平上,MHK3?rpoS在胞内和胞外Hcp的分泌均有显著升高(P<0.05),最高时分别为MHK3的1.59倍和1.31倍;同时,MHK3?rpoS对大肠杆菌(Escherichia coli) E5的杀菌能力约为MHK3的1%。研究表明,rpoS对鳗弧菌MHK3株的生长情况、泳动性、明胶酶活性及酪蛋白酶活性均无显著调控作用,但对平台早期的菌膜形成能力具有一定的负调控作用,在转录和翻译水平上也负调控Hcp的表达。而在杀菌能力上,rpoS发挥一定的正调控作用。说明菌株的杀菌能力强弱并非直接与Hcp的表达和分泌量正相关。本研究为进一步阐明T6SS的调控机制及其介导的杀菌作用机制提供了新思路,并丰富了其理论基础。     

光照强度对铁皮石斛组培幼苗生长及生理特性的影响

采用铁皮石斛试管苗,以组培室常用光照强度条件[25μmol/(m2·s)]为对照(CK),设置了3个较大光照强度处理[即T1:50μmol/(m2·s),T2:75μmol/(m2·s),T3:100μmol/(m2·s)],研究不同光强对铁皮石斛幼苗素质及生理特性的影响。结果表明,T2处理在对每瓶苗数和单苗绿叶数等指标影响差异不显著的前提下极显著地提高了单苗茎粗和单苗鲜重,亦显著地提高了单苗平均根直径、总根体积及总根尖数,使植株根冠协调生长的同时还显著地提高了叶片SPAD值和蔗糖合成酶活性。相关分析结果还显示,在25~100μmol/(m2·s)光强范围内,叶片SPAD值与单苗茎粗、总根尖数及叶片蔗糖合成酶活性呈显著的正相关。因此,生产铁皮石斛优质种苗的适宜组培光照强度大小为75μmol/(m2·s),叶片SPAD值可能是衡量铁皮石斛幼苗素质的一项关键指标。     

GM-CSF与生长抑素共表达基因疫苗的构建和鉴定

以基因疫苗pVGS/2SS-asd为模板，采用分子生物学方法，分别获得目的片段粒细胞-巨噬细胞集落刺激因子（ GM-CSF）和含有乙肝表面抗原S基因的生长抑素基因（ SS）。以共表达质粒pIRES为载体，采用基因工程方法，将GM-CSF和SS基因片段分别克隆到载体的多克隆位点A和多克隆位点B上，构建共表达基因疫苗pIRES-GM-CSF/2SS，旨在同时表达GM-CSF和SS两种蛋白。获得表达质粒后，酶切和测序鉴定该共表达基因疫苗，结果显示，该共表达基因疫苗pIRES-GM-CSF/2SS构建成功，为该共表达基因疫苗的后续研究奠定了良好的基础。     

生长抑素基因在猪胃组织中表达发育性变化及品种比较

 选用生长速度快的瘦肉型猪大白猪和生长速度慢的肥胖型猪二花脸作为试验动物 ,用相对定量RT PCR方法 ,研究猪胃体部组织中生长抑素 (somatostatin ,SS)基因表达发育性变化并进行品种间比较。结果表明 ,(1)出生当天两品种猪胃体部组织中SSmRNA表达水平较高 ,但出生后第 3天均出现显著下降 (P <0 .0 5 ) ;(2 )从 3日龄到 30日龄胃体部组织中SSmRNA表达在二花脸猪和大白猪均表现为上升 ,二花脸猪在 90日龄时达到高峰 ,随后下降。而大白猪在 30日龄之后保持相对稳定 ;(3)二花脸猪胃体组织中SSmRNA表达从出生到 90日龄均显著高于大白猪 (P <0 .0 5 ) ,二花脸猪胃体组织中SS表达自 12 0日龄下调 ,12 0～ 180日龄期间大白猪和二花脸猪胃体部SSmRNA表达没有间差异 (P >0 .0 5 )。以上结果提示 ,猪胃体部组织中SS基因表达调控有特定的时序性 ,并且呈现显著的品种差异 ,这是否与胃结构和功能的发育有关 ,还有待进一步研究。     

可溶性淀粉合成酶SSⅢ基因对马铃薯的遗传转化

马铃薯是淀粉生产中重要的农作物之一,而可溶性淀粉合成酶SSⅢ是可溶性淀粉合成酶的主要活性成分,通过基因工程的手段来研究SSⅢ基因在淀粉合成中的功能可以用于改良马铃薯淀粉的品质。本研究采用根癌农杆菌介导法将强组成型表达启动子CaMV35S驱动的可溶性淀粉合成酶SSⅢ基因的RNA干扰表达载体导入马铃薯栽培品种克新1号和克新4号中,获得了65株卡那霉素抗性植株。对抗性植株PCR检测结果表明,SSⅢ基因的干扰片段已整合到马铃薯基因组中,RT-PCR检测表明SSⅢ基因在转录水平上受到了明显抑制。该研究为马铃薯淀粉品质的改良奠定了基础。     

Study on the impact of wastewater irrigation on the quality of oils obtained from olives harvested by hand and from the ground and extracted at different times after the harvesting

Nowadays, lots of efforts are made in Tunisia for the exploitation of wastewater in agriculture in order to face a very elevated mobilization of resources in water (90%). At Sfax, a Governorate placed in the South of Tunisia, the annual rainfall rarely exceeds 200 mm, so the climate is fairly arid. The significant water deficit can be reduced with the reuse of treated wastewater (TWW). The Sfax wastewater originated from the municipal wastewater treatment plant (WWTP) localized at 5 km in the south of Sfax, Tunisia. This WWTP is an aerated lagoon process receiving industrial wastewaters. Its treatment capacity is 24,000 m³/day. Part of TWW is sent to the olive crops of El Hajeb, as part of a proposed wastewater use in agriculture. Already the wastewater is used to irrigate olive trees and intercrops such as cotton, oats and sorghum silage (Charfi et al., 1999). The aim of the present work was to determine the impact of the irrigation utilizing wastewater on the quality of the oil. The oils analysed were extracted from olives hand-picked directly from the tree and from olives that have fallen under the trees. Moreover, a study on the olive storage has been made in order to evaluate in which way the collection of the fruit could influence the quality of the oil.     

中国黄羽鹌鹑消化道生长抑素细胞的免疫组织化学研究

【目的】研究中国黄羽鹌鹑消化道生长抑素(Somatostatin,SS)细胞的分布及形态学特点。【方法】采集中国黄羽鹌鹑的食管、嗉囊、腺胃、肌胃、十二指肠、空肠、回肠、盲肠及直肠,常规方法制备石蜡切片,用链霉亲和素-生物素-过氧化物酶复合物(streptavidin-boin-peroxidase complex,SABC)免疫组织化学方法进行SS细胞定位。【结果】SS细胞主要分布于腺胃及小肠各部位,其中以腺胃分布数量最高,十二指肠次之,空肠、回肠及直肠分布均较少;食管、嗉囊、肌胃及盲肠处均未发现有其分布。统计分析结果表明,腺胃SS细胞的分布数量显著高于肠道各部(P<0.05),而肠道各部位间不具有显著性差异(P>0.05)。SS细胞的形态以圆形、椭圆形、三角锥形及梭形为主,多分布于腺胃腺叶内细胞之间、肠腺上皮细胞之间和肠黏膜上皮细胞之间。SS细胞的分布数量在雌雄鹌鹑各相应部位间不具有显著性差异(P>0.05),且形态特征相同。【结论】中国黄羽鹌鹑消化道SS细胞呈现由小肠头端向直肠尾端逐渐减少的分布趋势,在腺胃处分布数量最高,形态多为圆形、椭圆形、三角锥形及梭形,这可能与其消化道相应部位的生理功能有关。     

Babesia bigemina infection in yak (Poephagus grunniens L.): Molecular detection and characterization

Yaks contribute significantly in the Himalayan high land economy. Specific information on prevalence of babesiosis in yaks is lacking. A fast and reliable PCR assay targeting Babesia bigemina small subunit ribosomal RNA sequence (SS rRNA) was laboratory standardized for molecular detection of B. bigemina in yaks. Restriction digestion of the PCR amplified 675 bp target sequence with Vsp I confirmed the prevalent species of Babesia as B. bigemina. Nucleotide sequencing and phylogenetic analysis of PCR amplified 675 bp SS rRNA sequence revealed a close genetic relationship with other bovine isolates of B. bigemina. A PCR based survey involving 94 blood samples of yak from the National Research Centre on Yak, Dirang, Arunachal Pradesh detected infection in 5.32% of yak blood samples, which was significantly higher in comparison to microscope based detection of infection in 2.13% blood smears. This is the first report on sensitive PCR based detection of B. bigemina infection in yaks and PCR-RFLP and nucleotide sequence analysis based molecular characterization of the B. bigemina isolated from yaks.     

鸡胃肠道生长抑素(SS)mRNA表达的组织特异性

以30dArborAcre(AA)肉鸡为模型,采集胃肠道样品,采用相对定量RT-PCR方法研究了生长抑素(SS)mRNA在鸡胃肠道分布的组织特异性。结果表明,腺胃SSmRNA的表达量高于所有肠段,差异极显著(P<0.01);十二指肠和空肠SSmRNA的表达丰度相似,二者均显著高于回肠(P<0.05)。定性研究显示,肌胃和结直肠均有SSmRNA表达,但其表达量显著低于腺胃、十二指肠、空肠和回肠。SSmRNA在主要的消化(腺胃)、吸收(十二指肠和空肠前段)器官的高丰度表达,提示SS对营养物质的消化吸收具有重要的调控作用。异性     

The Effect of Different Nitrogen Form on Key Enzyme Activity of Sugarbeet（Vulgaris L.） Carbon and Nitrogen Metabolism

This article analyses the effect of the proportion of the different nitrogen forms on key enzyme activity of carbon and nitrogen metabolism under the condition of nutritional water while Tian Yan-7 was used as experimental material.The result showed that nitrate reductase(NR) activity in the leaves gradually enhanced with the increase of NO3^-,No matter in root or leaves,glutamina synthetase(GS) activity first enhanced with increasing NH4^ when NH4^ was lower than that of NO3^-,and GS activity was the highest when NH4^ and NO3^- was equal,then GS activity declined with NH4^ increasing further,In the anaphase of growth,synthetic activity in root of sucrose synthetase(SS) in the mixed NH4^ and NO3^- was obviously highr than or NO3^- alone,Both of the root and sugar yields were the highest when the proportion of NH4^ and NO3^- was 1:1.