Standing wave of finite-amplitude in an circular basin with uneven bottom

The effect of the particle cover over the density interface between two layers of fluids and of the suspended solid particles in the upper turbulcnt layer on the turbulent entrainment has been studied experimentally. The entrainment distance D is a function of the time of power: D=kt, where =0.200-0.130p. For suspended particles in the upper layer and pure 2-layer fluid is equal to 0.200, but the value of k for the suspended particles is smaller than that for the pure 2-layer fluid. The non-dimensional entrainment velocity is E=KRiln, where n=1.50+0.93 p. It is shown that the particle cover over the interface changes the power of Ril in the entrainment and hinders the turbulent entrainment. The variation rule of E for the suspended particles is the same as that for the pure 2-layer fluid, but the K value of the former is smaller than that of the latter. The turbulent mixing mechanism has been discussed.

roIC基因和MT基因特性及其表达的研究

植物种子萌发、开花结实和衰老等一系列生长发育过程，都受到植物激素的影响。细胞分裂素作为重要的生长调节物质，对其传统生物化学和生理学特性的研究已积累子大量资料。随着分子生物学的发展，对植物激素的研究又进一步从单纯的生物学描述阶段深入到分子水平研究的阶段。尤其是近年来对来自病原微生物植物激素相关基因的研究，为揭示细胞分裂素的作用机理和细胸分裂素的水平调节机制的阐明开辟了新的途径。 根瘤农杆菌T-DNA上ipt、iaaM和iaaH基因和发根农杆菌的rol基因表达产物与植物激素的代谢有关。rolC基因是位于发根农杆菌T-DNA区的12号开放读框，编码细胞分裂素-β-葡萄糖苷酶，水解结合态细胞分裂素为自由态细胞分裂素。ipt基因编码异戊烯基转移酶，是细胞分裂素合成过程中的关键酶。 本文用PCR方法从发根农杆菌（Agrobacterium rhizogenes）1601质粒中扩增 rolC基因，并构建CaMV 35S启动子驱动下的双元表达载体。以农杆菌介导的叶盘法，分别对野生型烟草（Nicotiana tabacum L. cv. W38）和已转入异戊烯基转移酶基因（ipt）的3F1和3F2烟草进行转达化。Southern blot和Northern Dot Blot分析表明，rolC基因已导入烟草植株，并具有转录活性。转基因烟草的形态特征与细胞分裂素过量表达的植株表现出的特征一致。 用ELISA方法测定转基因烟草植株中激素的含量，结果显示，单独转rolC基因烟草和同时转入rolC和ipt两个基因的烟草，细胞分裂素的水平有不同程度的提高。转基因烟草表现多芽、节间缩短、叶色深绿等现象。同时，转基因烟草内部发生生理变化，如总自由氨基酸、脯氨酸在正常情况下较对照减少，气孔延迟关闭。在干旱胁迫下，转基因烟草随水势的降低、总自由氨基酸和脯氨酸的变化与对照不同。转基因烟草在开始干旱阶段较对照的总自由氨基酸和脯氨酸含量低，随着干旱胁迫的加深，植物中自由氨基酸的含量增加，但转基因植物自由氨基酸的含量高峰值出现时间较对照推迟。干旱胁迫48小时后，恢复给水，转基因植物较对照易恢复正常生长状态，表明转细胞分裂素基因植物抗旱能力增强。另外，叶片总蛋白SDS-PAGE电泳分析表明，转基因植物蛋白质含量高于对照，某些蛋白组分所占比例也明显提高。 综上所述，转rolC和ipt基因烟草的形态和生理变化，是细胞分裂素过量表达引起植物体内激素失衡的结果。

Y chromosome haplotypes reveal prehistorical migrations to the Himalayas

By using 19 Y chromosome biallelic markers and 3 Y chromosome microsatellite markers, we analyzed the genetic structure of 31 indigenous Sino-Tibetan speaking populations (607 individuals) currently residing in East, Southeast, and South Asia. Our results showed that a T to C mutation at locus M122 is highly prevalent in almost all of the Sino-Tibetan populations, implying a strong genetic affinity among populations in the same language family. Furthermore, the extremely high frequency of H8, a haplotype derived from M122C, in the Sino-Tibetan speaking populations in the Himalayas including Tibet and northeast India indicated a strong bottleneck effect that occurred during a westward and then southward migration of the founding population of Tibeto-Burmans. We, therefore, postulate that the ancient people, who lived in the upper-middle Yellow River basin about 10,000 years ago and developed one of the earliest Neolithic cultures in East Asia, were the ancestors of modem Sino-Tibetan populations.

眼镜蛇(Naja naja atra)毒膜毒素MT-I的生物学效应研究

从眼镜蛇毒中纯化出膜毒素MT-I,该毒素与磷脂酶A_(2)产生协同溶血效应,使小鸡颈二腹肌等标本产生进行性挛缩,对体外Hut-78细胞有杀伤作用,腹腔注射能引起家猫的心电图异常。

蜂猴(Nycticebus coucang)和树鼩(Tupaia belangeri chinensis)mt DNA 10种限制酶物理图谱

本研究用10种限制性内切酶对蜂猴和树鼩肝脏线粒体DNA进行了分析. 蜂猴线粒体DNA, BglⅠHind Ⅲ、PstⅠ、SalⅠ和XhoⅠ均各只1个切点、EcoRⅠ、BglⅡ和Pvu Ⅱ各有2切点, BamHⅠ和 EcoRⅤ 分别有3个切点. 对于树鼩线粒体 DNA, BglⅡ、Hind Ⅲ、PstⅠ、SalⅠ和 XhoⅠ均只1个切点, BamHⅠBglⅠ和 PvuⅡ 分别有2个切点, EcoRⅠ 有3个切点, EcoRⅤ有4个切点. 根据单酶和双酶解片段的数目和分子量, 建立了蜂猴和树鼩线粒体 DNA 的物理图谱。