人胚胎干细胞定向分化为神经前体细胞

采用单层贴壁分化的方法在无血清条件下诱导同源饲养层培养的人胚胎干细胞定向分化,得到了高比例的神经前体细胞(97.5±0.83)%(P＜0.05).这些神经前体细胞具有分化为神经元、星形胶质细胞和少突胶质细胞的能力.在长期的传代培养中发现,随着培养时间的延长,nestin阳性的神经前体细胞比例下降,同时发育能力也发生了变化.在传代培养的早期,神经前体细胞发育为神经元的比例很高,几乎没有胶质细胞分化出来.随着培养时间的延长,胶质细胞的比例逐渐上升.这与体内神经系统的发育过程非常相似.进一步研究发现具有bHLH (basic helix-loop-helix) 结构域的转录因子neurogenein2(Ngn2) 和Olig2可能在这一变化中起重要作用.因此,人胚胎干细胞来源的神经前体细胞能够模拟体内神经发育的模式,为在体外研究人的神经发育和再生医学奠定了基础.

不同藏獒群体血液蛋白遗传变异与聚类分析

为了分析不同群体藏獒血液蛋白基因座的遗传变异及藏獒与其他犬种的亲缘关系,试验采用聚丙烯酰胺凝胶电泳技术,以青海藏狮犬和青海土种犬为对照,对2个藏獒群体的9个血液蛋白基因座的遗传变异进行了检测。结果表明:河曲藏獒群体内遗传变异较青海藏獒丰富,而两个藏獒群体间的遗传分化程度很低(GST=0.0187);青海藏獒与青海藏狮犬、青海土种犬的遗传关系近于河曲藏獒,并且4个青藏高原犬群在聚类图上形成一个独立的分支,与其他犬种之间遗传关系较远。

藏獒群体遗传结构及遗传分化研究

采用不连续垂直板聚丙烯酰胺凝胶电泳技术,对河曲藏獒和青海藏獒2个群体86只犬的9个结构基因座(Tf、Po、Es-1、Es-2、Sα2、Hb、Alb、Pr、Amy)的遗传变异情况进行了检测,探讨了2个藏獒群体的遗传结构和遗传分化。结果表明,河曲藏獒群体内遗传变异较青海藏獒丰富,而2个藏獒群体间的遗传分化程度很低(GST=0.018 7);较大的基因流(Nm=14.543 7)是2个藏獒不同地理群体间遗传分化水平低的主要原因。

间接免疫荧光法鉴别小鼠早期胚胎性别的研究

以间接免疫荧光法检测昆明系小鼠早期胚胎雄性特异性H-Y抗原的表达。结果表明: 54%的胚胎为H-Y阳性(雄性); 46%为H—Y阴性(雌性)。经与昆明系小鼠的自然性比率(♂:52%;♀:48%)比较, 两者无显著性差异。经细胞遗传学方法确证, 以免疫荧光法鉴别的胚胎性别, 雄性的鉴别准确率为75.5%; 雌性为82.97%. 还就影响鉴别准确率的若干因素以及该方法在生产中的应用前景等问题进行了分析讨论。表3参14

中国株丙型肝炎病毒(HCV)感染猕猴后5^NTR-C区基因组的cDNA序列分析

从2份受丙型肝炎病毒(HCV)感染的献血员血清(CX1、CX2)、第一代感染HCV猕猴血清(CX3)、第二代感染HCV猕猴血清(CX4)中提取RNA, 用自行设计的HCV 5^非编码区和核心区C5^NTR-C区引物进行逆转录PCR, 经扩增克隆并序列分析, 结果显示: CX1 cDNA全长779bp, CX2 cDNA 778bp, CX3 cDNA 776bp, CX4 cDNA 777bp。CX1株和CX4株均在5^NTR nt-216有一C的插入, CX3和CX4区nt385-387处的3个碱基缺失; CX1株与CX2、CX3、CX4比较同源性分别为98.07%、96.15%、95.25%; CX2与CX3、CX4的同源性分别为96.28%、95.76%; CX3与CX4的同源性为97.56%。

Phylogeny and zoogeography of the cyprinid genus Epalzeorhynchos Bleeker (Cyprinidae : Ostariophysi)

A total of 62 variable osteological and external characters was found among the five currently recognized species of Epalzeorhynchos. When the genera Crossocheilus and Paracrossocheilus are combined as the outgroup, only 30 of these characters can be polarized. This includes six autapomorphies. The remaining 24 polarized characters form a data matrix which yields a single, 26-step tree with a Consistency Index (CI) of 1 and a Retention Index (RI) of 1, The analysis was also performed on a combined dataset in which the 32 unpolarized characters (characters for which the combined outgroup was dimorphic) were added and coded as missing data (i.e., "?"), Analyzing this data matrix with all multistate characters ordered generates the same single most-parsimonious tree with a length of 63 steps, a CI of 0.98 and a RI of 0.97, When either Crossocheilus or Paracrossocheilus is used as the sole outgroup, the same single most-parsimonious tree is produced although the numbers of informative characters and some of the polarities differ. Evidence is presented to support the following hypotheses: (1) E, kalopterus + E, frenatus + E. bicolor + E. munensis form a monophyletic group; (2) E. frenatus + E, bicolor + E, munensis form a monophyletic group with E, kalopterus as its sister group; this speciation event is congruent with the predictions of vicariant speciation mode I; and (3) E. bicolor and E. munensis are sister groups, again congruent with vicariant speciation mode I, Evidence presented here also supports the zoogeographical hypothesis that the faunas of the Indochinese region and the Greater Sundas are more closely related to each other than either of them is to the lower Salween basin fauna and that the lower Mekong, Chao Phraya, and Mac Khlong basin faunas are more closely related to each other than any of them is to the Greater Sundas, In addition, the monophyly of Epalzeorhynchos is also preliminarily discussed by including either Paracrossocheilus or Crossocheilus in the ingroup. It is demonstrated that E. bicornis clusters with Paracrossocheilus when Paracrossocheilus is included in the ingroup. It seems likely that the taxonomic position of E. bicornis will be resolved as more fishes of the Crossocheilus group are included in future studies.

Molecular and morphological analysis of endangered species Gymnodiptychus integrigymnatus (Teleostei: Cyprinidae)

Gymnodiptychus integrigymnatus is a critically endangered species endemic to the Gaoligongshan Mountains. It was thought to be only distributed in several headwater-streams of the Longchuanjiang River (west slope of the Gaoligongshan Mountains, belonging to the Irrawaddy River drainage). In recent years, dozens of G. integrigymnatus specimens have been collected in some streams on the east slope of the Gaoligongshan Mountains (the Salween drainage). We performed a morphological and genetic analyses (based on cytochrome b and D-loop) of the newly discovered populations of G. integrigymnatus to determine whether the degree of separation of these populations warrants species status. Our analysis from the cytochrome b gene revealed that nine individuals from the Irrawaddy drainage area and seven individuals from the Salween drainage area each have only one unique haplotype. The genetic distance between the two haplotypes is 1.97%. Our phylogenetic analysis revealed that G. integrigymnatus is closely related to highly specialized schizothoracine fishes. Analysis from the mitochondrial control region revealed that G. integrigymnatus has relatively high genetic diversity (pi was 0.00891 and h was 0.8714), and individuals from different river drainages do not share the same haplotypes. The AMOVA results indicated 87.27% genetic variability between the Salween and Irrawaddy populations. Phylogenetic trees show two major geographic groups corresponding to the river systems. We recommend that G. integrigymnatus should be considered as a high priority for protected species status in the Gaoligongshan Mountains National Nature Reserve, and that the area of the Gaoligongshan Mountains National Nature Reserve should be expanded to cover the entire distribution of G. integrigymnatus. Populations of G. integrigymnatus from different river systems should be treated as evolutionarily significant units.

A new species of genus Pseudogyrinocheilus (Teleostei: Cyprinidae) from Guangxi, China

A new species, Pseudogyrinocheilus longisulcus, was discovered from a tributary of Pearl River in Jingxi Co., Guangxi, China, The new species can be distinguished from other species of Pseudogyrinocheilus by the following combination of characteristics: prolonged post-labial grooves, and extended antero-medially close to anterior end of middle lower lip, but not meeting with its counterpart; posterior margin of lower lip free; scales of abdomen from thorax to pectoral-fin base embedded under skin; lateral-line scales 40-42; dark stripe longitudinal along lateral line on flank. The key to the species of Pseudogyrinocheilus is provided.

Cloning,Expression and Sequence Analysis of A Luciferase Gene from the Chinese Firefly Pyrocoelia pygidialis

从一种来自中国日行性萤火虫(云南窗萤)发光器官mRNA中克隆、测序并表达了有功能的荧光素酶.云南窗萤荧光素酶的cDNA序列有1647个碱基,编码548个氨基酸残基.从推测得到的氨基酸序列的比对分析得出:云南窗萤的荧光素酶与来自Lampyris noctiluca,L.turkestanicus和Nyctophila cf.caucasica三种萤火虫的荧光素酶有97.8%的序列一致性.从推测得出的氨基酸序列进行系统发育分析,其结果表明:云南窗萤和Lampyris+Nyctophila聚在一起,与同属的发光强夜行性的萤火虫不形成的单系.云南窗萤荧光素酶在大肠杆菌中表达的条带大约70kDa,并且在有荧光素存在时发出黄绿色荧光.对荧光素酶的结构模拟和分析表明,云南窗萤荧光素酶基因的氨基端和羧基端结构域之间的裂沟处存在这5个多肽环,这正是从其他荧光素酶推测得到的催化荧光反应时的底物结合位点.云南窗萤和窗萤属的其他3种萤火虫的荧光素酶卡目比,有13个不同氨基酸位点,位于模拟分子结构的表面.对于这些多肽环、不刚氨基酸残基和晶体结构的进一步研究有利于解释日行和夜行性萤火虫荧光素酶的差异.

尖吻蝮蛇毒凝血酶及其生产方法

本发明提供一种具有止血功能的尖吻蝮蛇毒凝血酶Ⅰ及其生产方法。经阴离子交换剂柱层析法分离纯化和快速蛋白纯化工作站程序再纯化，本发明从我国特产尖吻蝮(Agkistrodon acutus)的蛇毒中得到纯度在97％以上的尖吻蝮蛇毒凝血酶Ⅰ；经测定，该酶Ⅰ由A、B两个亚基(链)组成，其中，A亚基含有135个氨基酸，B亚基含有126个氨基酸。与现有蛇毒凝血酶(如Reptilase)相比，它是一个全新的新型酶止血剂；经药理、毒理、药代等研究表明，本发明的尖吻蝮蛇毒凝血酶Ⅰ是一个见效快、副作用小、安全有效的新型止血剂。

一种尖吻蝮蛇毒凝血酶及其生产方法

本发明经阴离子交换剂柱层析法分离纯化及快速蛋白纯化工作站程序再纯化，从我国特产尖吻蝮(Agkistrodon acutus)蛇毒中得到纯度在97％以上的尖吻蝮蛇毒凝血酶Ⅱ；经测定，该酶Ⅱ由A、B两个亚基(链)组成，其中，A亚基含有125个氨基酸，B亚基含有123个氨基酸；与现有蛇毒凝血酶(如Reptilase)相比，它是一个全新的新型酶止血剂。经药理、毒理、药代等研究表明，它是一个见效快，副作用小的、安全有效的新型止血剂。