中国大陆若干群体的黑果蝇的线粒体DNA多态性研究

本文研究了果蝇Ｄ．ｖｉｒｉｌｉｓ种群Ｄ．ｖｉｒｉｌｉｓ线粒体ＤＮＡ（ｍｉｔｏｃｈｏｎｄｒｉａｌＤＮＡ,ｍｔＤＮＡ）的多态性。用９种限制性内切酶ＸｂａⅠ,ＥｃｏＲⅠ,ＰｓｔⅠ,ＨｉｎｄⅢ,ＢｇｌⅡ,ＳａｃⅠ,ＳｃａⅠ,ＥｃｏＲＶ和ＰｕｖⅡ,对青岛、南京、上海、宁波与泉州５个Ｄ．ｖｉｒｉｌｉｓ群体的ｍｔＤＮＡ进行了限制性片段长度多态性（ｒｅｓｔｒｉｃｔｉｏｎｆｒａｇｍｅｎｔｓｌｅｎｇｔｈｐｏｌｙｍｏｒｐｈｉｓｍ,ＲＦＬＰ）的研究。在５群体中,发现５种不同的酶切图谱,它们彼此之间的遗传差异π为０．４６％－１．７６％,群体内遗传差异πｉｊ为０．００％－０．３３％,群体间的差异ｄｘｙ,为０．００％－０．８２％。分布于中国大陆的Ｄ．ｖｉｒｉｌｉｓ的群体间遗传差异在总遗传差异中所占比例γｓｔ值为２４．６２％。我们发现,Ｄ．ｖｉｒｉｌｉｓ的栖息环境对ｍｔＤＮＡ的遗传变异有十分明显的影响,而不同地理纬度的群体之间其遗传距离并无倾群（ｃｌｉｎｅ）表现。     

线粒体DNA缺失与神经肌肉性疾病的研究

应用PCR技术对13例神经肌肉疾病患者的线粒体DNA缺失进行了研究。结果表明,其中二例肢带型肌营养不良症患者骨骼肌组织和一例帕金森氏病患者的血细胞线粒体DNA中存在至少526bp的缺失。提示线粒体突变在一些神经肌肉性疾病的发生中起一定的作用。 Abstract: Using PCR technique,we analysed the skeletal muscle and blood of 13 patients with neuromuscular disaeases.The results show that a mutant mitochondrial DNA with at least 526bp deletion exits in the skeletal muscles of 2 patients with Erb muscular dystrophy and in the blood of a patients with Parkinson’s disease.From our results,mitochondrial DNA mutations could be an important contributory factor to neuromuscular diseases.     

RAPD分析─鉴定柑桔体细胞杂种的快速方法

本文利用改进的DNA提取方法,从Volkamer柠檬(Citrus volkameriana Ten. and Pasq.)和酸橙(C. aurantium L.)及其原生质体杂种植株的叶片中抽提总DNA,进行RAPD(Random Amplified Polymorphic DNA)分析。结果表明: 在随机选取的15种引物中,有10种可单独或与其它引物一道鉴定这一组合的体细胞杂种。与形态学性状观察、同工酶及ONA杂交分析等方法比较,RAPD分析是一种可在试管苗期即可直接、准确、快速鉴定柑桔体细胞杂种的方法。     

笼养白头叶猴夏季水分摄入与消耗的初步研究

叶片中的水分含量是白头叶猴水分的主要来源,占水分需求总量的８３．６８％,其它的１６．３２％来自于自由水。在笼养条件下,白头叶猴可饮用自来水,野生状态下,动物饮用露水或雨水。尽管饮水行为不是每天都有,但能经常观察到,特别是在夏季雨后．除了体表和呼吸系统的水分蒸发外,白头叶猴通过尿和粪便丢失的水分含量分别是４４．６８％和５５．３２％。     

在小鼠胚胎干细胞进行基因打靶的策略

基因打靶技术是一种通过同源重组按预期方式改变生物活体的遗传信息的实验手段,与小鼠胚胎干细胞培养系统相结合,使得人们可以方便地将各种突变引入小鼠体内,得以从生物整体水平上研究高等真核生物基因的表达、调控及其生理功能.扼要介绍了近年来在小鼠胚胎干细胞进行基因打靶的研究进展.     

五个氨基酸磷光性质的研究

研究了5个氨基酸的磷光特性、光谱、寿命和最小检测量.以色氨酸(Trp)的磷光最强,在λ_ex/λ_em=290/438 nm,最小检测量为1 ng,酪氨酸(Tyr)其次(284/390 nm)为Trp的1/10,苯丙氨酸(Phe)在276/386 nm,脯氨酸(Pro)在308/454 nm,组氨酸(His)在320/466 nm,其磷光只有Trp的1%.Phe与Trp磷光寿命最长,在7 s左右;His最短,只有0.49 s;Tyr 2.8 s,Pro 1.34 s.另外研究氨基酸在甲醇,乙醇,丙醇,丁醇中及pH对氨基酸磷光性质的影响.还计算了Stokes位移能量及激化态pK^*_a值.     

博莱霉素-Ce(Ⅲ)对DNA的切断机理初探

根据外切核酸酶Ⅲ酶解博莱霉素-Ce(Ⅲ)［BLMA5-Ce(Ⅲ)］作用过的双链直线型DNA时, 酶解速率明显增大, 酶解产物除5′-dAMP、5′-dGMP、5′-dCMP和5′-dTMP 4种单核苷酸外, 还有其他成分存在的实验事实, 推测出BLMA5-Ce(Ⅲ)在DNA双链的特定部位沿5′→3′的方向切断磷酸二酯键, 使DNA的双链上形成多个暴露的3′-OH末端.     

Protective Effects of Pyridoxal Phosphate Against Glucose Deprivation-Induced Damage in Cultured Hippocampal Neurons

Abstract: When hippocampal cultures were deprived of glucose, massive release of lactate dehydrogenase (LDH), an indicator of neuronal death, occurred via NMDA receptor activation. Addition of pyridoxal phosphate (PLP; 1 and 10 µ M ) inhibited this LDH release in a concentration-dependent manner. Prior exposure to PLP evoked more potent inhibitory effects on LDH release compared with those treated at the onset of glucose deprivation. Furthermore, PLP inhibited the reduction of intracellular content of pyruvate induced by glucose deprivation, which was accompanied by the reversal of intracellular ATP depletion. A noteworthy elevation of extracellular glutamate in response to glucose deprivation was completely reversed by addition of PLP. Aminooxyacetic acid, a potent inhibitor of PLP-dependent enzymes, antagonized the effects of PLP on LDH release, pyruvate production, and ATP formation. These results suggest that PLP protects neurons from glucose deprivation-induced damage by enhancing the formation of energy-yielding products and relieving extracellular load of glutamate. The observed phenomena further indicate that PLP might be used prophylactically against neuronal death induced by metabolic disorders.     

Construction of a recombinant human GM-CSF/MCAF fusion protein and study on its in vitro and in vivo antitumor effects

A novel cytokine fusion protein was constructed by fusing granulocyte macrophage colony stimulat-ing factor (GM-CSF) with monocyte chemotactic activating factor (MCAF), which acts as a factor directing effector cells (monocytes) to a target site. The recombinant human GM-CSF/MCAF fusion protein could sustain the growth of GM-CSF-dependent cell line TF1 and was chemotactic for monocytes. The in vitro antitumor effect showed that rhGM-CSF/MCAF could activate monocytes to inhibit the growth of several human tumor cell lines, including a promyelocyte leukemia cell line HL-60, a lung adenocarcinoma cell line A549, a hepatoma cell line SMMC-7721 and a melanoma cell line Bowes. Furthermore, the cytotoxicity of monocytes activated by rhGM-CSF/MCAF against HL-60 and A549 was greater than that activated by GM-CSF or MCAF alone, even greater than that activated by a combina-tion of GM-CSF and MCAF, suggesting that the fusion protein has synergistic or enhanced effects. The in vivo anti-tumor effect indicated that     

Construction of a trivalent candidate Shigella vaccine strain with host-vector balanced-lethal system

A trivalent liveShigella vaccine candidate FSD01 against S.flexneri 2a, S.sonnei and S.dysenteriae I was constructed. This candidate strain was based on the S.flexneri 2a vaccine T32. By homologous recombination exchange, the chromosomalasd gene of T32 was site-specifically inactivated, resulting in the strain unable to grow normally in LB broth, while anotherasd gene of S.mutans was employed to construct an Asd⁺ complementary vector. This combination ofasd ^- host/Asd⁺ vector formed a balanced-lethal expression system in T32 strain. By use of this system, two important protective antigen genes coding for S.sonnei Form I antigen and Shiga toxin B subunit were cloned and expressed in T32, which led to the construction of trivalent candidate vaccine FSD01. Experimental results showed that this strain was genetically stable, but its recombinant plasmid was non-resistant. Moreover, it was able to effectively express trivalent antigens in one host and induce protective responses in mice against the challenges of the above threeShigella strains.