红细胞生成刺激素(EPO)的纯化

 本文用中空纤维柱超滤浓缩尿,再经离子交换层析、聚焦层析、凝胶过滤和制备型聚丙烯酰胺凝胶电泳(PAGE)-层析等四步从15L再生障碍性贫血患者尿中获得约2mg EPO制品。比活性达10 300U/mg蛋白。该制品在分析型PAGE中呈一条区带。     

寡聚脱氧核苷酸d(G-C)_3的激光喇曼谱及其分析

用改进的固相磷酰三酯法合成了oligo-d(G-C)_3。以氩离子激光为激发光源,波长488nm.,在室温条件下,分别测定了纯化后的oligo-d(G-C)_3和其组分单体5’-dGMP和5’-dCMP的激光喇曼谱。观察到被测定的物质在300-2500cm~(-1)频率区间,各自都有其特征的谱形和喇曼峰。5’-dGMP和5’-dCMP谱中大多数特征峰在寡聚体的谱中消失,而在oligo-d(G-C)_3谱中出现了几处新的喇曼峰。经查证,峰832,851和899cm~(-1)系糖-磷酸主链的特征喇曼峰,另外几处峰与DNA的构象有关。实验结果表明oligo-d(G-C)_3在水溶液中(室温)主要以B-构象存在。     

ApoB-54.8, a truncated apolipoprotein found primarily in VLDL, is associated with a nonsense mutation in the apoB gene and hypobetalipoproteinemia

A new, large kindred with hypobetalipoproteinemia and a previously undescribed truncated form of apolipoprotein B (apoB) has been identified. The asymptomatic, Caucasian male proband (CK, aged 37 years) has total plasma cholesterol, triglyceride, low density lipoprotein-(LDL) cholesterol, high density lipoprotein- (HDL) cholesterol, and apoB concentrations of 108, 131, 32, 50, and 16 mg/dl, respectively. Plasma samples of 11 family members spanning three generations, which had less than 5th percentile concentrations of LDL-cholesterol, contained three apoB bands detected on immunoblots: the normal apoB-100 and apoB-48 and an unusual band of apparent molecular mass of 299,356 +/- 9580 daltons (approximately 54% the molecular weight of apoB-100). Additional immunoblotting experiments using several different anti-apoB monoclonal antibodies showed that the carboxyl terminal of apoB-100 had been deleted somewhere between amino acid residues 2148-2488. A segment of genomic DNA from the proband was amplified by polymerase chain reaction (PCR) between nucleotides 7491-7791 of Exon 26 of the apoB gene. The DNA segment was cloned into pGEM3Zf(-) and sequenced. A C----T transition was found at nucleotide 7665, resulting in a premature stop codon at amino acid residue 2486 corresponding to apoB-54.8. These results were confirmed by direct sequencing of PCR products from three apoB-54.8 positive and three apoB-54.8 negative kindred members. Allele-specific oligonucleotides were used to identify other affected family members. Cosegregation of apoB-54.8 with the C----T transition occurred in all cases. Based on haplotypes constructed from restriction fragment length polymorphism, variable number of tandem repeats, and 5' insertion/deletion analyses and from the presence or absence of apoB-54.8, it was possible to assign a single allele of apoB to the mutation throughout the family. In contrast with other shorter truncations such as apoB-31, apoB-40, and apoB-46, which are found with particles in the HDL density range, and apoB-89 that is found primarily with LDL, apoB-54.8 was found primarily in very low density lipoproteins, much less in LDL, and was virtually absent in HDL. This suggests that the length of the truncation may significantly affect the metabolism of the associated lipoprotein particles.     

急进高海拔时健康人夜间睡眠、呼吸状态和血氧饱和度的变化

在海拔2300m选择健康成年男性5人,急进抵海拔4660m,用多导监测仪分别在两地连续7h监测夜间睡眠、呼吸状态和血氧饱和度变化,进行自身对比。结果发现:(1)急进高海拔后,总睡眠时间、有效睡眠指数、Ⅲ～Ⅳ期深睡眠均较中度高原减少(p<0.01);总觉醒时间、Ⅰ～Ⅱ期浅睡眠高海拔较中度高原增多(p<0.05):(2)急进高海拔后,有3名健康人出现周期性呼吸,其中1名健康者出现周期性呼吸119次,伴有中枢性睡眠呼吸暂停,最低Sao_2为78％;(3)同海拔高度夜间睡眠时与清醒时Sao_2相比较,中度高原下降4.2％,高海拔下降11.2％(p<0.01);高海拔与中度高原夜间清醒时Sao_2相比较下降7.4％,睡眠时下降14.4％(p<0.001)。结果提示:(1)睡眠加重了高原人原有的低氧血症;(2)低氧血症导致睡眠结构的紊乱和睡眠质量的降低;(3)睡眠中出现的周期性呼吸,应视为机体的一种自我保护机制;(4)频发的周期性呼吸或睡眠呼吸暂停将影响大脑机能。     

一种计算哺乳动物内禀增长率（rm）的方法

一、概述内禀增长率(r_m)是一个最基本的种群参数,它的测定和计算在动物生态学的研究中占有十分重要的地位。从20年代开始,已发展出多种计算动物r_m值的方法,如下所述。     

松茶间作茶树叶片的解剖构造和气孔活动

本文利用光镜技术和MK-3型自动气孔计对松茶间作和单作茶园茶树叶片的解剖构造和气孔传导力进行了比较研究。研究表明,间作茶园茶树叶片的上表皮、栅拦组织和全叶均比单作茶树薄,分别为单作茶树的82.7％,78.2％和67.2％,叶质柔嫩。叶片气孔传导力比单作茶园低。嫩叶传导力>老叶;1芽5叶新梢按叶序3叶>2、4叶>1、5叶;按树冠垂直分布,冠上叶(0—5cm)>冠中叶(10—15cm)>冠下叶(30cm左右)。说明气孔传导力不仅受生态条件影响,与自身的叶龄、叶位等生理机能也有密切关系。     

杭州湾六市土地生态环境的数量评价及其在国土规划上的意义

在系统调查分析和特尔斐测定的基础上,选取人口密度、耕地人口负荷量、土地工业经济密度、居民点、厂矿用地、>25°土地面积、单位森林蓄积占用土地、耕地非旱涝保收面积7项指标,应用分值权重累加、系统聚类分析和模糊综合评价3种方法对杭州湾6市土地生态环境作综合分析评价,结果可应用于国土规划实践,对探讨土地生态环境评价的理论与方法有参考价值。     

病毒单糖的研究 Ⅰ.颗粒体病毒(GV)单糖的气相色谱分析

本文介绍了颗粒体病毒中单糖的气相色谱分析法,对所得病毒单糖色谱图中的主要组分进行了分析鉴定,证明组成病毒的单糖成分有:鼠李糖、核糖、木糖、甘露糖、葡萄糖和阿拉伯糖。并用相应单糖峰高比值,区分了它们间的异同。病毒单糖分析结果。能与血清学和裂解气相色谱法分析鉴定病毒的结果相符。     

基因定点诱变删除及天然α型心钠素的分泌型表达

用基因定点诱变技术,删除了pO_1α ANF表达质粒中的33对碱基,使人α型心钠素结构基因直接与大肠杆菌分泌型表达质粒pIN-Ⅲ-OmPA中的信号肽酶切位点编码区相连,构成天然人α型心钠素的表达质粒pANF,在IPTG诱导下表达28肽的天然人α型心钠素。纯化后的表达产物具有天然心钠素的放免活性和很强的舒张血管的生物活性。     

Epstein-Barr病毒基因组编码的BARF-1和EC-LF4蛋白质与免疫球蛋白结构同源

将EB病毒蛋白质BARF-1和EC-LF4与NBRF蛋白质库的序列进行局部同源性检索以及与已知的Ig V或C功能区相关分子进行对准比较,检查了同源性积分的统计学意义,并进行了二级结构预测和疏水性分析,确定了BARF-1的第13-124位和第126-221位残基片段分别与V和C样功能区类似,EC-LF4的第20-135位残基片段与V样功能区相似,BARF-1是非膜蛋白,EC-LF4是膜整合蛋白,其胞外部分近膜侧有一个类似于Ig绞链区的序列。因此,BARF-1与Ig轻链结构相似,EC-LF4与CD8抗原的第一条链相似。根据Ig超族分子的一般功能(即介导细胞粘附和细胞识别),推测EC-LF4可能作为一种粘附分子与淋巴细胞表面的Ig相关分子结合而促进EB病毒对淋巴细胞的感染。BARF-1因已知与病毒复制有关,与Ig超族的一般功能无关。EC-LF4和BARF-1的Ig样功能区可能来源于EB病毒对宿主细胞Ig基因的整合。