微量注射抗TGF_β-1抗体对爪蟾发育的影响

注射抗TGF_β-1抗体至2细胞胚胎的一个裂球中,产生了三个级别的卵黄团外露畸型胚胎,YE-1、YE-2和YE-3。它们的产生与抗体的注射量有关。它们的共同特征是注射后胚胎能正常发育至囊胚,卵黄团在注射一侧外露,外露部分无任何中胚层组织。高剂量注射时,主要产生YE-1级别的畸型胚胎,其中大部分在注射侧从头至尾不存在肌肉组织,中胚层发育受到了极大的影响。降低注射剂量后所产生的YE-2畸型胚胎,在注射侧有一定的肌肉组织,但明显小于未注射侧。YE-3是所受影响最小的畸型胚胎,YE-3 V 的注射侧产生了与未注射侧非常接近的肌肉组织。活体观察畸型胚胎的形成过程,发现不同级别的畸型胚胎与注射侧的原肠运动所受影响程度和范围有关。高剂量注射时,几乎整个注射侧的原肠运动受到了影响,由此产生了YE-1,而低剂量注射时,注射侧只有部分区域受到影响,因此产生了YE-3 v 和YE-3 d。无论是原肠运动受阻,还是中胚层发育受到影响,其原因可能是抗TGF_β-1抗体阻抑了中胚层诱导的过程,所以由此也进一步证实了TGF_β相关蛋白与中胚层诱导有关。     

RT—PCR法检测大鼠脑组织及C6细胞中β—APP的表达

β-淀粉样蛋白(β-AP)是阿尔茨海默氏病(Alzheimer’s disease)病人老年斑的主要成分,它是β-淀粉样前体蛋白(β-APP)剪切后的产物。β-APP基因在体内存在β-APP_(695),β-APP_(751)β-APP_(770)。等几种主要的转录物,它们的区别在于Kunize丝氨酸蛋白酶抑制区(KDI)编码序列的存在和缺失。通过RT-PCR技术,用针对KPI编码区两侧序列的一种特异性引物可由总RNA样品中扩增出反映以上三种转录物的cDNA片段。实验表明,胎鼠脑组织中未检测到β-APPmRNA;6月龄大鼠海马组织,大脑皮层中只检测到β-APP_(695);在神经胶质瘤细胞系C6中存在β-APP_(695),β-APP_(751),β-APP_(770),其中β-APP_(770)占优势。     

山羊品种间体细胞核移植研究

萨能奶山羊是著名的奶用山羊品种,波尔山羊则是世界著名的肉用山羊品种.为了研究波尔山羊体细胞在奶山羊卵母细胞中的去分化,我们将成年波尔山羊的颗粒细胞或耳皮肤成纤维细胞作为供核细胞(试验组),移入奶山羊中Ⅱ期的去核卵母细胞透明带下,经电融合和离子霉素与6-二甲基氨基嘌呤(6-DMAP)激活,直接移入同期发情奶山羊输卵管或经体内培养,将发育的重构胚移人同期发情羊子宫内.妊娠早期作B超诊断,确立妊娠的观察至足月.同时将奶山羊的35日龄胎儿成纤维细胞作供核细胞(对照组),按试验组同样方法处理,将重构胚直接移入同期发情的奶山羊输卵管内.结果试验组,波尔羊颗粒粒细胞与耳皮肤成纤维细胞的融合率分别为78.2%(115/147)、57.4%(116/202),重构胚卵裂率为85.8%(115/134),桑椹胚、囊胚的发育率38.8%(52/134),早期妊娠三头,分别于妊娠40、60、60日龄终止妊娠.对照组,融合率为89.5%(136/152),早期妊娠率为42.9%(6/14),四头受体足月分娩,产四头公羊羔,其中三头存活,一头分娩时死于肺不扩张,并体重过大,显示胎儿过大综合症.经基因型鉴定证实,这四头克隆羔羊均源于同一胎儿成纤维细胞系.以上结果表明,波尔羊体细胞核在奶山羊卵母细胞中能够去分化,并维持一定程度的发育.     

B→O血型转变工具酶α-半乳糖苷酶cDNA克隆及表达

 α-半乳糖苷酶是实现 B→O血型转变、制备通用型血的关键工具酶 .利用反转录 PCR方法从中国海南 Catimor咖啡豆中克隆α-半乳糖苷酶 c DNA,插入嗜甲基酵母 P.pastoris分泌表达载体 p PIC9K中 ,转化 P.pastoris GS1 1 5,筛选高表达重组菌株 .经甲醇诱导表达 7d后 ,发酵液总蛋白分泌量约 1 .2 mg/ml,SDS- PAGE呈现约 41 k D特异表达带 ,与专一性底物对 -硝基 -苯基 -α- D-吡喃半乳糖苷反应证明 ,表达产物具有 α-半乳糖苷酶活性 ,最高达到 1 8U/ml.初步实验表明 ,表达的 α-半乳糖苷酶可酶解 B型红细胞 ,成功实现 B→O血型转变 .     

种子脱水耐性及其与种子类型和发育阶段的相关性

种子脱水耐性是种子发育过程中获得的综合特性,是判断种子贮藏持性的一个重要依据。当种子获得脱水耐性时,生理,形态和结构会发生相应的变化,包括糖,蛋白质,脂类和抗氧化系统等保护性物质的合成,各种保护性物质不是单独作用的,而是协同调节种子的脱水耐性。不同的植物种子,其脱水耐性不同,并且随着种子的发育而变化。关于种子脱水耐性的获得,主要有2种观点,一种认为是数量性状,另一种认为是突变性状。种子库收集种子保存时,适时采集和适度脱水才能有效地延长种子的贮藏寿命。     

繁缕和无瓣繁缕六个居群的数值分析

对繁缕（Stellaria media）和无瓣繁缕（S.apetala）的6个居群的57个性状进行Q－聚类和R－聚类的研究。结果表明：（1）Q－聚类中,用一条结合线,可以把繁缕的4个居群聚为一类,无瓣繁缕的2个居群聚为一类。这一结果支持肥繁缕和无瓣繁缕划分为两个物种;（2）R－聚类中,发现了呈现完全正相关、极大正相关和极大负相关的性状,并根据R－聚类的结果,运用一条适当的结合线,把繁缕和无瓣繁缕的57个性状划为5个类群,并分析了各性状的分类学意义。     

脑干内的混沌

对脑干听觉诱发电位进行了非线性动力学分析,计算了关联维数Ｄ２和最大Ｌｙａｐｕｎｏｖ特征指数,确认ＢＡＥＰ是一个来源于低维混沌动力系统的时间序列,从而证明人类脑干存在着混沌现象,利用满足最小互信息标准的最佳延迟重构了二维混沌吸引子。     

FKBP12.6 protects heart from AngII‐induced hypertrophy through inhibiting Ca2+/calmodulin‐mediated signalling pathways in vivo and in vitro

We previously observed that disruption of FK506‐binding protein 12.6 (FKBP12.6) gene resulted in cardiac hypertrophy in male mice. Studies showed that overexpression of FKBP12.6 attenuated thoracic aortic constriction (TAC)‐induced cardiac hypertrophy in mice, whereas the adenovirus‐mediated overexpression of FKBP12.6 induced hypertrophy and apoptosis in cultured neonatal cardiomyocytes, indicating that the role of FKBP12.6 in cardiac hypertrophy is still controversial. In this study, we aimed to investigate the roles and mechanisms of FKBP12.6 in angiotensin II (AngII)‐induced cardiac hypertrophy using various transgenic mouse models in vivo and in vitro. FKBP12.6 knockout (FKBP12.6^?/?) mice and cardiac‐specific FKBP12.6 overexpressing (FKBP12.6 TG) mice were infused with AngII (1500 ng/kg/min) for 14 days subcutaneously by implantation of an osmotic mini‐pump. The results showed that FKBP12.6 deficiency aggravated AngII‐induced cardiac hypertrophy, while cardiac‐specific overexpression of FKBP12.6 prevented hearts from the hypertrophic response to AngII stimulation in mice. Consistent with the results in vivo, overexpression of FKBP12.6 in H9c2 cells significantly repressed the AngII‐induced cardiomyocyte hypertrophy, seen as reductions in the cell sizes and the expressions of hypertrophic genes. Furthermore, we demonstrated that the protection of FKBP12.6 on AngII‐induced cardiac hypertrophy was involved in reducing the concentration of intracellular Ca²⁺ ([Ca²⁺]i), in which the protein significantly inhibited the key Ca²⁺/calmodulin‐dependent signalling pathways such as calcineurin/cardiac form of nuclear factor of activated T cells 4 (NFATc4), calmodulin kinaseII (CaMKII)/MEF‐2, AKT/Glycogen synthase kinase 3β (GSK3β)/NFATc4 and AKT/mTOR signalling pathways. Our study demonstrated that FKBP12.6 protects heart from AngII‐induced cardiac hypertrophy through inhibiting Ca²⁺/calmodulin‐mediated signalling pathways.     

Transmembrane kinase 1-mediated auxin signal regulates membrane-associated clathrin in Arabidopsis roots

Clathrin-mediated endocytosis (CME) is the major endocytic pathway in eukaryotic cells that directly regulates abundance of plasma membrane proteins. Clathrin triskelia are composed of clathrin heavy chains (CHCs) and light chains (CLCs), and the phytohormone auxin differentially regulates membrane-associated CLCs and CHCs, modulating the endocytosis and therefore the distribution of auxin efflux transporter PIN-FORMED2 (PIN2). However, the molecular mechanisms by which auxin regulates clathrin are still poorly understood. Transmembrane kinase (TMKs) family proteins are considered to contribute to auxin signaling and plant development; it remains unclear whether they are involved in PIN transport by CME. We assessed TMKs involvement in the regulation of clathrin by auxin, using genetic, pharmacological, and cytological approaches including live-cell imaging and immunofluorescence. In tmk1 mutant seedlings, auxin failed to rapidly regulate abundance of both CHC and CLC and to inhibit PIN2 endocytosis, leading to an impaired asymmetric distribution of PIN2 and therefore auxin. Furthermore, TMK3 and TMK4 were shown not to be involved in regulation of clathrin by auxin. In summary, TMK1 is essential for auxin-regulated clathrin recruitment and CME. TMK1 therefore plays a critical role in the establishment of an asymmetric distribution of PIN2 and an auxin gradient during root gravitropism.     

Comparative study on direction selectivity and functional organization of the primary visual cortical cells in monkeys and cats

Although the directionally selective cells in many visual cortical areas are organized in columnar manner, the functional organization of direction selectivity of area VI in the monkey still remains unclear. We quantitatively studied the proportion of directionally selective cells, direction selectivity and the functional organization of the striate cortical cells in the monkey and compared those with the cat. The results show that the direction selectivity and directional organization of striate cortical cells in the monkey are significantly weaker than those in the cat, suggesting that the species difference between the two kinds of animal is related to their different anatomic pathways.