Transformation of Neurospora crassa with the trp-1 gene and the effect of host strain upon the fate of the transforming DNA

Summary Neurospora trp-1 ⁺ transformants, obtained by transforming a trp-1 inl strain with plasmid DNA containing the wild type trp1 ⁺ gene, were characterized by genetic and Southern blot analyses. The transforming trp-1 gene integrated at or near the resident site in all of the trp-1 ⁺ transformants obtained with circular DNA or DNA cut within the trp-1 coding region. The frequency of homologous integration decreased substantially when the donor DNA was cleaved outside the trp-1 coding region. The transformants were very stable mitotically and, in general, also showed meiotic stability. Analysis of trp-1 ⁺ transformants obtained with another recipient strain, trp-1 ⁺ ga-2 aro-9 inl, showed that homologous integration of donor DNA occurred in only 20% of the transformants, whether circular or linear DNA was used. Thus, the host strain employed for transformation appears to be a major factor in determining the fate of transforming DNA. Southern blot analysis of transformants showed that integration of the transforming DNA at the homologous site occurred by double crossover or gene conversion events rather than by insertion of the entire plasmid DNA. Multiple and apparently non functional integration events were observed in some transformants.     

三取代型钛钨硅酸盐体内抑瘤效应的免疫机制探讨

目的:探讨三取代型钛钨硅酸盐(WT)体内抑瘤效应的免疫机制。方法:建立荷H22肝癌小鼠模型,WT连续灌胃10d,取出肿瘤称重测定抑瘤率。用MTT比色法测定荷H22肝癌小鼠淋巴细胞转化的活性及NK细胞的杀伤活性。通过形态学观察和流式细胞仪检测WT诱导BEL-7402细胞的凋亡。结果:WT可显著抑制荷瘤小鼠肿瘤生长(P<0.05),提高荷瘤小鼠淋巴细胞转化的活性及NK细胞的杀伤活性(P<0.05),并诱导肿瘤细胞发生凋亡。结论:WT的抑瘤作用与机体免疫功能的增强有关。     

引入关联维的表面肌电信号的特征提取

考虑到表面肌电信号的非平稳特性,本研究在传统特征提取的基础上,又引入了非线性动力学中的关联维,通过小波系数的标准差和关联维重新构造特征向量,将其送入自组织映射网络对拇指弯曲、食指弯曲和无名指弯曲三种手势动作进行分类识别。结果表明:引入关联维的特征提取方法其识别正确率明显优于传统的小波变换的方法。可见,关联维作为一种新的特征参数,为肌电信号的特征提取提供了新的思路。     

Antigens targeted to the Leishmania phagolysosome are processed for CD4+ T cell recognition

Processing of antigen for recognition by class II-restricted CD4⁺ T cells occurs within acidic compartments of the antigen-presenting cell. The exact nature of this compartment has yet to be precisely defined, however, but may vary depending upon the cell type studied and the antigen used. The acidic compartments of macrophages are also responsible for the degradation of ingested micro-organisms and play host to others which are adapted to an intracellular existance. To determine whether the phagolysosome (PL) formed in activated macrophages after ingestion of Leishmania parasites is also a site for entry of antigen into the class II presentation pathway, we have used the approach of genetic transformation. Hence, Leishmania were transfected with the genes for the protein antigens ovalbumin (OVA) and β-galactosidase (β-gal) and after infection were able to deliver these antigens specifically into the PL. Delivery of antigen to this site resulted in the ability of infected macrophages to present these antigens to antigen-specific CD4⁺ T cells. After taking into account the absolute levels of antigen uptake by macrophages, a 4-h processing period for OVA delivered by this or a soluble route led to equivalent levels of T cell activation. Unlike macrophages pulsed with soluble OVA, those with PL-targeted OVA still retained the ability to stimulate T cells after a 24-h processing period. This enhanced lifespan of antigen in macrophages corresponded to the kinetics of degradation of the parasite, suggesting slow release of antigen into the processing pathway. β-gal presentation from the PL was tenfold less efficient under the same conditions. In addition to providing the first information on antigen processing in a protozoan PL, these studies highlight the usefulness of genetically transformed parasites for these types of studies.     

生长因子作为评价胚胎质量的生物学标记物的研究

目的　研究表皮生长因子 (epidermalgrowthfactor,EGF)、转化生长因子 - β1(transforminggrowthfactor- β1,TGF -β1)、胰岛素样生长因子 -Ⅱ (insulin -likegrowthfactor-Ⅱ ,IGF -Ⅱ )做为评价小鼠胚胎质量生物学标志物的可能性。方法　取小鼠二细胞胚胎 ,分为正常和异常两组 ,体外培养至囊胚期 ,对胚胎的生长发育及着床能力进行形态学观测 ;检测胚胎培养液中三种生长因子的含量 ,研究生长因子含量与胚胎质量间的关系。结果　 1.正常组胚胎培养液中EGF、IGF -Ⅱ的含量显著高于异常组 ,且EGF含量与胚胎生长发育的形态学指标呈正相关 ,但与着床指标相关不显著 ;2 .IGF -Ⅱ与胚胎生长发育及着床指标均呈正相关。 3.TGF - β1的含量两组间差异无显著性。结论　胚胎培养液中EGF、IGF -Ⅱ含量测定可反映胚胎生长发育能力 ,IGF -Ⅱ还可反映胚胎着床能力 ,从而有利于了解胚胎功能状态及生存潜力 ,为胚胎质量的检测提供了一条新的思路     

Critical role for SV40 small-t antigen in human cell transformation

Defining the ability of simian virus 40 (SV40) to transform human cells has become of even greater importance with the increased understanding that this virus may play a role in some human malignancies. This report documents the requirement for viral small-t (ST) antigen in large-T (LT)-driven transformation of primary fibroblasts, a requirement that cannot be met by a well-known oncogene, c-Ha-ras (EJ-ras), which can cooperate with LT in rodent systems. The cellular gene telomerase is not essential for transformation, although transformed clones are not immortal without it. Similarly, an immortal mesothelial cell line has been developed using LT and telomerase. Immortalized mesothelial cells are morphologically normal, but can be transformed by introduction of ST, or ST + ras, but not by ras alone. It is likely that ST will be required along with LT for transformation of most human cell types.     

身心因素与肠易激综合征患者生活质量的相关研究

目的调查肠易激综合征(IBS)患者生活质量状况并评估躯体及心理因素对它的影响。方法采用肠易激综合征生活质量量表(IBS-QOL)、临床症状问卷、艾森克人格问卷简式(EPQ-RSC)、简明心境问卷简式(POMS-SF)、医学应对问卷(MCMQ)对120例IBS患者进行测查,将IBS患者的心理健康水平(人格、情绪、应对)及躯体症状(肠道症状、肠外症状、睡眠障碍)与IBS患者生活质量进行相关分析。结果IBS患者IBS-QOL的8个因子和总分均显著降低(P<0.05),其中健康忧虑和饮食限制降低最为明显,除IBS症状外,肠外症状、睡眠障碍、精神心理异常在IBS患者中也很常见。心理因素中EPQ-RSC神经质(N)分、POMS中焦虑、抑郁等多项因子分及总分、MCMQ屈服积分与IBS-QOL总分呈负相关;躯体因素中IBS症状、肠外症状、睡眠障碍积分与IBS-QOL总分呈负相关。结论肠易激综合征患者的生活质量明显降低,除躯体症状外,心理功能失调也是决定患者生活质量的重要因素。     

Effect of α1-protease inhibitor (α1-antitrypsin on the intensity of transformation of phytohemagglutinin-stimulated lymphocytes

₁-Antitrypsin (₁-AT) reduces the intensity of transformation of human peripheral blood lymphocytes stimulated by phytohemagglutinin. The degree of inhibition is determined by the antiprotease activity of the ₁-AT. Maximal inhibition of transformation was shown to be 50%. Participation of ₁-AT in the control of activity of lymphoid tissue cells is postulated.Laboratory of Immunogenetics, Research Institute of Transplantology and Artificial Organs, Ministry of Health of the USSR, Moscow. (Presented by Academician of the Academy of Medical Sciences of the USSR V. N. Orekhovich.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 89, No. 1, pp. 35–36, January, 1980.     

Biolistic transformation of Trichoderma harzianum and Gliocladium virens using plasmid and genomic DNA

Biolistic (biological ballistic) and protoplast-mediated procedures were compared as methods for transforming strains of Gliocladium virens and Trichoderma harzianum. For biolistic transformation, conidia were bombarded using a helium-driven biolistic device to accelerate M5 tungsten particles coated with plasmid or genomic DNA. DNA from either source contained a bacterial hygromycin B resistance gene (hygB) as a dominant selectable marker. The same sources of DNA were also used to transform protoplasts using a standard polyethylene glycol-CaCl₂ protoplast fusion protocol. Hygromycin B-resistant (HygB^R) transformants were recovered from all strains, methods, and DNA sources except for genomic DNA used with the protoplast method. The biolistic procedure was technically simpler, and increased transformation frequency and genetic stability in the progeny as compared with the protoplast-mediated transformation. Southern analysis of homokaryotic HygB^R progenies showed that the transforming sequences were integrated into the genome of the recipient strains, and apparently were methylated. This is the first study presenting detailed results on biolistic transformation of a filamentous fungus.     

Assessment of chemical carcinogen-induced transforming activity using BALB/c-3T3 cells

Summary The BALB/c-3T3 cell transformation assay evaluates the morphologic transforming potential of test chemicals using cultured mammalian cells as targets. The assay is semiquantitative and employs a contact-inhibited clone of cells derived from the original BALB/c-3T3 mouse cell line. Transforming activity, or a focus, is recognized as a dense layer of morphologically altered cells superimposed on a monolayer of the normal cell phenotype. The induction of transforming activity in a standard assay has been reported to correlate well with the carcinogenicity of many test chemicals in rodent bioassay; however, the standard assay does not detect carcinogens of all chemical classes. This report describes an operational protocol for the standard BALB/c-3T3 cell transformation assay. In addition, it provides assay acceptance criteria and a discussion of a method to evaluate transforming activity data.