Klinefelter综合征患者和双亲对诱变剂敏感性研究

为了解诱变剂对Ｋｌｉｎｅｆｅｌｔｅｒ综合征发生的影响，对Ｋｌｉｎｅｆｅｌｔｅｒ综合征患者，患者双亲及对照进行丝裂霉素Ｃ，乙醛或乙醇诱导非二倍体，染色体结构畸变及微核观察，发现丝裂霉素Ｃ诱导的患者当色体结构畸变和微核均显著多于对照和双亲，乙醛和乙醇能诱导非二倍体和微核增加，但患者和双亲增加的程度极显著高于对照，提示Ｋｌｉｎｅｆｅｌｔｅｒ综合征患者对于丝裂霉素Ｃ，乙醛和乙醇诱导染色体畸变更敏感。双亲对     

Liver and Heart Mitochondrial Succinate Dehydrogenase Activity of Newborn Rats in Anoxic Hypoxia and Starvation

Succinate dehydrogenase activity was determined in the liver and heart of newborn rats after 3 and 48 hours' exposure to anoxic hypoxia (10% O₂) and after 48 hours' starvation. Control determinations were made on newborn animals of corresponding ages, full term foetuses (21 days), infantile (1 and 2 weeks) and full grown animals. Hypoxia for 3 h had no influence on succinate dehydrogenase activity at all in either the heart or liver mitochondria of the newborn animals. After 48 h no difference was observed in the liver between the hypoxic animals and the starved controls of the same age, though starvation itself had resulted in a significant increase in activity, as much as 42%. When liver mitochondrial succinate dehydrogenase in normal mitochondria was activated by preincubation mitochondria with the substrate, the activity increase obtained was greater than that resulting from starvation. The increase in activity in the heart of the hypoxic or starved animals was not significant (< 10%).     

Detection of the homology among proteins by immunochemical cross-reactivity between denatured antigens. Application to the glyceraldehyde 3-phosphate dehydrogenases from different species

It was previously proposed that an immunological cross-reaction between two denatured proteins is evidence for an homology betweeen their amino sequence (Arnon &; Maron, 1971; Arnheim et al., 1971) and that detection of such a cross-reaction could then be a rapid method to detect sequence homologies (Zakin et al., 1978). In order to test the possibilities of such a methodology, using proteins of known structure, glyceraldehyde 3-phosphate dehydrogenases from different sources are compared by immunochemical techniques. The antibodies raised against the native enzyme from E. coli K 12 can only recognize the homologous antigen, the glyceraldehyde 3-phosphate dehydrogenase from B. stearothermophilus and to a lesser extent that from halibut. In contrast, the antibodies raised against the denatured enzyme from E. coli K 12 can recognize the glyceraldehyde 3-phosphate dehydrogenases from man, ostrich, chicken, sturgeon, halibut, lobster and yeast, when in their denatured state. The present results show unambiguously that through exposure of buried sequences, the immunochemical detection of sequence homologies among proteins is more discriminating when unfolded proteins are used, rather than native ones. It is also proposed that the use of denatured proteins both as immunogens and antigens would be a useful tool in studying biochemical evolution.     

Sequence analysis of the gene coding for glyceraldehyde-3-phosphate dehydrogenase (gpd) of Podospora anserina: use of homologous regulatory sequences to improve transformation efficiency

Summary The glyceraldehyde-3-phosphate dehydrogenase (gpd) gene of Podospora anserina has been isolated from a genomic library by heterologous hybridization with the corresponding gene of Curvularia lunata. The coding region consists of 1014 nucleotides and is interrupted by a single intron. The amino-acid sequence encoded by the gpd gene shows a high degree of sequence identity with the corresponding gene products of various fungi. Multiple alignments of all fungal GPD sequences so far available resulted in the construction of a phylogenetic tree. The evolutionary relationships of the various fungi belonging to different taxa will be discussed on the basis of these data. Sequence analysis of 1.9 kbp of the 5 non-coding region revealed the presence of typical fungal promoter elements. Utilizing different parts of the 5 regulatory sequence of the Podospora gpd gene, expression vectors containing a dominant selectable marker gene (hygromycin B phosphotransferase) have been constructed for the transformation of P. anserina protoplasts. The use of these homologous gpd regulatory sequences resulted in a significant increase in transformation efficiencies compared to those obtained with vectors in which the selectable marker gene is under the control of the corresponding heterologous promoter of Aspergillus nidulans.     

Mitochondrial antigens as targets of cellular and humoral auto-immunity in primary biliary cirrhosis

Several factors point toward an auto-immune pathogenesis for primary biliary cirrhosis (PBC), mostly based on the presence of serum auto-antibodies to mitochondrial antigens (AMAs) and autoreactive T cells (both helper and cytotoxic). Interestingly, epitopes recognized by AMA and T-cell clones are located within overlapping areas of the antigens. Moreover, a role for an imbalance in cytokine pattern and for natural-killer lymphocytes has also been proposed. Despite several experimental reports, no clear evidence is available regarding the interaction of these factors leading to bile duct destruction. This article reviews the current reports regarding the auto-immune reaction against mitochondrial auto-antigens in PBC.     

云南省傣族G6PD一个家系的突变型研究

在调查云南少数民族Ｇ６ＰＤ缺乏症时，采用Ｇ６ＰＤ硝基四氮唑蓝纸片法筛查，按ＷＨＯ标准化方法进行生化变异型鉴定，再用错配碱基ＰＣＲ引入酶切位点法进行ＤＮＡ突变型研究，首次在傣族中发现Ｇ６ＰＤｃＤＮＡ突变型：１３８８Ｇ→Ａ。     

萝摩甙抗自由基损伤作用的实验研究

目的:探讨萝摩甙对自由基所致脑损伤的神经元保护作用及机制。方法:复制脑缺血模型及H₂O₂诱导神经元损伤模型,分别测定大鼠脑组织、培养神经元中的丙二醛(MDA)含量以及培养神经元中的乳酸脱氢酶(LDH)漏出率、DNA断裂率和羟自由基清除率,观察萝摩甙对损伤神经元的保护作用。结果:萝摩甙可明显降低脑缺血造成的MDA的升高,亦可明显降低H₂O₂对神经元造成的LDH漏出率、DNA断裂率增加和丙二醛含量的升高,而且随着萝摩甙浓度的升高羟自由基清除率明显升高。结论:萝摩甙可通过清除自由基来保护神经元。     

Changes in the infectivity, pyruvate kinase activity, acid phosphatase activity and P-glycoprotein expression in glibenclamide-resistant Leishmania mexicana

We previously demonstrated susceptibility of Leishmania sp. to glibenclamide, a K⁺-ATP transport blocker which interacts with members of the superfamily of adenosine 5′ triphosphate-binding cassette transporters. In order to characterize the molecular differences between a sensitive Leishmania strain, NR(Gs), and an experimentally selected glibenclamide-resistant strain, NR(Gr), specific biochemical and functional parameters have been evaluated both in the wild type and in the resistant strain. Most noteworthy, NR(Gr) exhibit an increased expression of P-glycoprotein and a decreased activity of functional key enzymes such as acid phosphatase, a prominent virulent factor of the parasite, and pyruvate kinase, a key control enzyme for both carbohydrate and protein metabolism. The specific biochemical, metabolic and functional changes observed in the resistant strain correlated with a reduced infectivity of stationary phase NR(Gr) in J774 macrophages and suggested a mechanism to overcome the effect of glibenclamide. Received: 21 January 2000 / Accepted: 1 March 2000