L-鸟氨酸的混合菌种发酵研究

谷氨酸棒杆菌可发酵葡萄糖产L-鸟氨酸。通过连续筛选与驯化筛选到了产量较高的生产菌株CG1006。以GC/MS对发酵液成分的定性分析及鸟氨酸的产量为依据,优化了培养条件,产量从最初的14.346g/L提高到40.416g/L。初步考察了酵母菌CG1006-1对发酵液成分及产量的影响。结果表明混合菌种发酵可纯化发酵液成分。     

不同氮源对苦草(Vallisneria natans)生长及生理指标的影响

通过实验室静态模拟,研究了在富营养条件下(4.0 mg.L-1TN,0.2 mg.L-1TP)不同比例铵态氮和硝态氮(6∶0、5∶1、3∶3、1∶5和0∶6)对苦草〔Vallisneria natans(Lour.)Hara〕的生长与生理指标的影响。结果表明,随着铵态氮和硝态氮比例的下降,苦草相对生长率和蛋白质含量先升高后下降,超氧化物歧化酶(SOD)和谷氨酰胺合成酶(GS)活性逐渐下降,硝酸还原酶(NR)活性逐渐升高。在4.0 mg.L-1TN和0.2 mg.L-1TP条件下,若不考虑磷的作用,高浓度铵态氮对苦草的生理功能有影响,对其生长有明显的抑制作用;而当铵态氮浓度小于0.67 mg.L-1时却可以促进苦草的生长。     

星星草营养器官适应盐胁迫的结构特征

采用0．6％Na2CO3胁迫处理星星草[Puccinellia tenuiflora（Turcz．）Scribn．et Merr．]幼苗,光镜和电镜观察其根和叶的显微和超微结构。结果表明,星星草根的表皮向外突出形成密集的根毛;外皮层由1～2层细胞组成,排列较紧密;中皮层薄壁细胞排列疏松,形成发达的通气组织;内皮层呈典型的五面加厚;中柱鞘排列紧密,其壁加厚;初生木质部与初生韧皮部相间排列,初生木质部为5～7原型,中央为后生木质部导管,无髓存在。叶的表皮有表皮毛和丰富的蜡质层;叶上表皮泡状细胞数目较少,且深陷;气孔下陷,其下有较大的气室;叶脉有大、中、小3种维管束,大、中型维管束为C3型,小型维管束为C4型。星星草可能是介于C3和C4植物之间的类型,具有耐盐碱及耐干旱特征。     

水稻矮缩病毒昆明分离物抗血清制备及免疫捕捉PCR检测

由水稻矮缩病毒(Rice dwarf virus,RDV)引起的水稻矮缩病害,最早由日本报道,随后在东南亚等国以及我国的福建、云南等南方稻区普遍发生,云南主要发生于中部及南部地区[1]。水稻在苗期至分蘖期感病后,植株矮缩,分蘖增多,叶片浓绿,僵直,出现白斑,生长后期病稻不能抽穗结实,在暴发流行年份可以引起水稻的严重减产。RDV在分类上属于呼肠孤病毒科(Reoviridae)植物呼肠孤病毒属(Phytoreovirus)成员,病毒粒子为正十二面体球形结构,直径约为69.3nm,无刺突,无脂蛋白外膜包被,具有双层的蛋白衣壳[2]。病毒基因组由12条双链RNA片段组成,其中S8编…     

Landscape-scale variation in the seed banks of floodplain wetlands with contrasting hydrology in China

1. At a local scale, the species composition, diversity and spatial variation of wetland plant communities are determined primarily by spatial and temporal heterogeneity in their environments. Less is known about variation at a landscape‐level. The floodplain of the Changjiang (Yangtze) River in China includes hydrologically connected, subtropical wetlands with different hydrological characteristics. 2. We examined seed‐bank species composition and richness in marshes of two contrasting hydrological types: permanent marshes, fed by local runoff, and lakeshore marshes more closely connected to the regulated river. Lakeshore marshes are flooded annually to depth of approximately 1 m and during flooding they support an alternate, aquatic vegetation type. The soil seed bank in March was a comparative estimator of species diversity. At the beginning of the growing season it included seeds from both phases of alternating vegetation types associated with the annual hydrological cycle. 3. A regional pool of 101 species was detected in the seed banks of six wetlands associated with the river and its tributaries: 56 occurred in permanent marshes and 59 in lakeshore marshes, with only 15 common to both. Species rarefaction curves indicated that more species occurred in permanent than lakeshore marshes at equal numbers of individuals sampled. However, the more heterogeneous lakeshore seed banks were estimated (Chao 2) to have greater total species richness (81) than permanent marsh (60). 4. Analysis using Sørensen's coefficient of similarity and DCA ordination revealed complex variation, with much greater differences between hydrological types than within them, irrespective of geographical distance. The types also differed significantly in the composition of four functional groups of species. 5. Despite the potential for dispersal of propagules via the annually pulsing river system (hydrochory), at a regional and landscape scale, diversity is maintained largely by large‐scale temporal hydrological heterogeneity and smaller scale spatial and topographic heterogeneity.     

羊胎免疫调节因子制造工艺研究

目的:优选出羊胎免疫调节因子提取的最佳工艺。方法:采用正交实验设计L8(27),以淋巴细胞转化实验为考察指标进行实验,对提取过程中的6个指标进行了优化,确定了最佳提取工艺。结果:羊胎免疫调节因子最佳提取工艺为A1B2C2D1E2F2,即2月龄内羊胎粉碎10 m in,加1:4双蒸水常温下8000 r.m in-1离心后10K超滤膜超滤即得。     

哈茨木霉发酵液中肽类物质对豇豆根瘤结构和功能的影响

通过树脂吸附、离子交换、薄层层析、高效液相色谱系统等分离、纯化方法,从哈茨木霉(Trichoderm aharzianum)T2-16菌株发酵液中分离得到一种对豆科作物生长具促进作用的物质,通过质谱等方法鉴定为肽类物质。为探明该活性物质对豆科作物的促生机制,用该活性物质对豇豆种子浸种处理后,进行盆栽实验,通过对盆栽实验中根瘤结构与固氮活性变化的研究,结果显示,该活性物质可增加根瘤侵染组织的面积和根瘤细胞中类菌体的数量,降低根瘤细胞液泡化程度,促进根瘤中公共细胞周膜较多形成,加快类菌体的发育成熟,提高根瘤豆血红蛋白的含量,从而提高根瘤的固氮活性。     

猴副流感病毒SV5 PCR检测方法的建立与初步应用

目的建立检测SV5的PCR方法并加以初步应用。方法根据GenBank中报道的SV5序列,针对其中的SH基因设计引物进行PCR反应,扩增产物进行测序并用BLAST软件进行同源性比对,同时利用限制性内切酶的酶切反应以证实此PCR反应的特异性。在此基础上设计巢式PCR提高此方法的灵敏度。利用此方法对20份猴肾源细胞培养物和40份血清标本进行检测。结果利用设计的引物扩增出的序列测序结果证实与报道的SV5SH基因相对位置的序列一致。AccⅢ限制性内切酶可对PCR产物进行特异性酶切。巢式PCR比一次PCR的敏感度有所提高。用此方法检测的20份猴肾源细胞培养物和40份血清标本结果为阴性。结论初步建立了检测SV5病毒的PCR方法,排除实验室用20份猴肾源细胞培养物和40份血清标本SV5的污染。     

猴D型反转录病毒巢式PCR检测方法的建立

目的建立SRV-1巢式PCR检测方法并进行初步应用。方法针对SRV-1env基因的保守区序列,设计特异性引物,以感染SRV-1 Raji细胞提取出的含有前病毒DNA的基因组DNA为模板,进行巢式PCR反应。扩增产物测序后与GenBank报道的序列进行同源比对。将DNA样本进行10倍梯度稀释,以检测巢式PCR反应的灵敏度。使用该方法对正常Raji细胞以及感染SIV、STLV的外周血淋巴细胞DNA样本进行扩增,检测该方法的特异性。用建立的巢式PCR方法检测40份储存猴血标本。结果使用巢式PCR扩增出的特异片段经测序分析,结果证实与GenBank报道的序列一致。所建立的巢式PCR检测法检测限度可达1.5×10-3ng/μL,而且方法特异。用此方法检测40份猴血标本,未检测到阳性标本。结论初步建立SRV-1的巢式PCR检测方法,该方法灵敏、特异,为SRV-1的检测提供了一个快速、有效的手段。