Male-specific antigen: modification of potency by the H-2 locus in mice

Skin grafts from C57BL/10 (B10) male mice survive significantly longer than do B10.BR male skin grafts on (B10 x X B10.BR)F(1) females. This indicates that the H-2 locus influences the potency of the male-specific antigen in mice.     

Memory in mice as affected by intracerebral puromycin

The antibiotic, puromycin, caused loss of memory of avoidance discrimination learning in mice when injected intracerebrally. Bilateral injections of puromycin involving the hippocampi and adjacent temporal cortices caused loss of short-term memory; consistent loss of longer-term memory required injections involving, in addition, most of the remaining cortices. Spread of the effective memory trace from the temporal-hippocampal areas to wide areas of the cortices appears to require 3 to 6 days, depending upon the individual animal. Recent reversal learning was lost while longer-term initial learning was retained after bilateral injections into the hippocampal-temporal areas.     

Identification and characterization of a neuron-specific nuclear antigen in Drosophila

An antigen found only in neuronal nuclei of Drosophila melanogaster is revealed by staining with a monoclonal antibody (Mab44C11). This antigen appears early in development, before neurons show any other signs of antigenic or morphologic differentiation, and persists throughout development. This nuclear staining permits reliable detection of neurons in developmental studies of wild-type and mutant flies. Protein immunoblot analyses and immune precipitation experiments show that the neuronal nuclear antigen is a 50-kilodalton polypeptide.     

猪瘟基因疫苗免疫小鼠外周血细胞免疫动态变化研究

应用ＦＡＣＳ、ＭＴＴ法对猪瘟基因疫苗ｐｃＤＳＴ、ｐｃＤＳＷ免疫鼠外围血中ＣＤ４＾＋和ＣＤ８＾＋淋巴细胞数、淋巴细胞的转化功能等动态变化进行了观察。结果：ｐｃＤＳＴ、ｐｃＤＳＷ猪瘟基因疫苗免疫小鼠后,小鼠的外周血淋巴细胞对ＬＰＳ有强烈的反应性,ＣＤ４＾＋细胞数量增加,外周血淋巴细胞ＣＤ８＾＋细胞数量在一段时间内增加。ＣＤ４＾＋和ＣＤ８＾＋细胞数量在免疫后３２天达到高峰后开始下降。表明ｐｃＤＳＴ、ｐｃＤＳＷ质粒免疫小鼠后诱发免疫反应。     

刺梨主要基因型的RAPD鉴别

采用RAPD分子标记，构建了刺梨8个基因型的DNA指纹图谱和亲缘关系图。结果表明，以筛选出的16个随机引物进行PCR扩增，多态性检出率高，其中以OPB—11、OPW—02和OPAF—16多态性最好，能有效地用于供试材料的鉴别；基因型之间多态性百分率(PP)差异较大，以重瓣刺梨最高(60．9％)，无籽刺梨最低(48．3％)；通过RAPD遗传距离矩阵，采用UPGMA法构建了8个基因型的聚类图，并结合多态性百分率，分析了基因型之间，特别是重瓣刺梨、白花刺梨及无籽刺梨与5个栽培类型间的亲缘关系。     

鸡恒定链功能片段跨物种增强小鼠对新城疫F2抗原免疫作用的研究

【目的】研究恒定链(Invariant chain,Ii)功能片段作为载体的跨物种免疫增强作用及其潜在机制。【方法】构建基于鸡Ii功能片段与新城疫病毒抗原表位F2的嵌合体(Ii-F2、Cyt/Tm/Ii-key/F2/AP、Tm/Ii-key/F2/AP、Ii-key/F2/AP、Ii-key/F2),将其定向克隆至原核表达载体pET-32a中,转化大肠杆菌Rosetta(DE3)并用IPTG诱导表达,嵌合体融合蛋白纯化后免疫小鼠,用ELISA法测定血清抗体效价。同时,分别构建含鸡Ii和小鼠MHCⅡ类分子基因的真核表达载体,并将其共转染COS7细胞,通过激光共聚焦显微镜观察其在细胞内的共定位。【结果】用F2与Ii-key等Ii功能片段连接的融合蛋白免疫的试验组小鼠的抗体效价,较单独用F2抗原肽免疫的对照组小鼠产生的抗体效价提高了1.5~3倍。显微观察发现,鸡Ii和小鼠MHCⅡ分子在细胞内可以共定位。【结论】Ii具有跨越物种限制增强免疫的作用。     

Identification of an erythrocyte component carrying the Duffy blood group Fya antigen

The erythrocyte component carrying the Duffy blood group antigen Fya has been identified as a 35- to 43-kilodalton protein. The protein is degraded by proteases, chymotrypsin, and Pronase, which destroy its antigenicity on intact erythrocytes. Its unusual property of aggregating on being boiled in 5 percent sodium dodecyl sulfate with 5 percent 2-mercaptoethanol distinguishes it from other erythrocyte membrane proteins described to date.     

Specific expression of hepatitis B surface antigen (HBsAg) in transgenic mice

Two transgenic mice were obtained that contain in their chromosomes the complete hepatitis B virus (HBV) genome except for the core gene. These mice secrete particles of HBV surface antigen (HBsAg) in the serum. In one mouse, HBV DNA sequences that had integrated at two different sites were shown to segregate independently in the first filial generation (F1) and only one of the sequences allowed expression of the surface antigen. Among these animals the males produced five to ten times more HBsAg than the females. A 2.1-kilobase messenger RNA species comigrating with the major surface gene messenger RNA is expressed specifically in the liver in the two original mice. The results suggest that the HBV sequences introduced into the mice are able to confer a tissue-specific expression to the S gene. In addition, the HBV transgenic mice represent a new model for the chronic carrier state of hepatitis B virus infection.     

利用卡那霉素间接鉴定转基因抗虫棉的研究

研究了利用卡那霉素间接鉴定转基因抗虫棉的方法。结果表明,在棉花苗期使用8000mg/kg卡那霉素溶液处理子叶,或者在蕾期使用6000mg/kg卡那霉素溶液处理棉株顶部第2片展开叶,7～9d后非转基因棉株的叶片点液处出现黄色斑块,而转基因抗虫棉的叶片仍为正常绿色,从而简便有效地鉴别出转基因抗虫棉。经网室接虫测试和室内饲养生物学测试方法验证,该方法结果准确。     

Identification by ENDOR of Trp191 as the free-radical site in cytochrome c peroxidase compound ES

The chemical identity of the amino acid free-radical site that represents one of the two oxidizing equivalents stored in the H2O2-oxidized intermediate (compound ES) of the mitochondrial heme enzyme, cytochrome c peroxidase (CcP) has been sought for almost a quarter of a century. Site-directed mutagenesis alone cannot yield this answer. Low-temperature 35-gigahertz (Q-band) electron nuclear double resonance (ENDOR) spectroscopy was used to examine compound ES prepared from proteins containing specifically deuterated methionine or tryptophan, as well as the amino acid replacement Trp51----Phe. The results definitely identify the site of the radical in compound ES as tryptophan, most likely Trp191.     

Identification of p53 as a sequence-specific DNA-binding protein

The tumor-suppressor gene p53 is altered by missense mutation in numerous human malignancies. However, the biochemical properties of p53 and the effect of mutation on these properties are unclear. A human DNA sequence was identified that binds specifically to wild-type human p53 protein in vitro. As few as 33 base pairs were sufficient to confer specific binding. Certain guanines within this 33-base pair region were critical, as methylation of these guanines or their substitution with thymine-abrogated binding. Human p53 proteins containing either of two missense mutations commonly found in human tumors were unable to bind significantly to this sequence. These data suggest that a function of p53 may be mediated by its ability to bind to specific DNA sequences in the human genome, and that this activity is altered by mutations that occur in human tumors.     

Identification of human uromodulin as the Tamm-Horsfall urinary glycoprotein

The primary structure of human uromodulin, a 616-amino acid, 85-kilodalton glycoprotein with in vitro immunosuppressive properties, was determined through isolation and characterization of complementary DNA and genomic clones. The amino acid sequence encoded by one of the exons of the uromodulin gene has homology to the low-density-lipoprotein receptor and the epidermal growth factor precursor. Northern hybridization analyses demonstrate that uromodulin is synthesized by the kidney. Evidence is provided that uromodulin is identical to the previously characterized Tamm-Horsfall glycoprotein, the most abundant protein in normal human urine.     

Identification of polymers as major components of atmospheric organic aerosols

Results from photooxidation of aromatic compounds in a reaction chamber show that a substantial fraction of the organic aerosol mass is composed of polymers. This polymerization results from reactions of carbonyls and their hydrates. After aging for more than 20 hours, about 50% of the particle mass consists of polymers with a molecular mass up to 1000 daltons. This results in a lower volatility of this secondary organic aerosol and a higher aerosol yield than a model using vapor pressures of individual organic species would predict.     

Specificity of antigen recognition by human lymphocytes in vitro

Delayed hypersensitivity reactions in vivo are exquisitely specific, in terms of both a lack of response after induction of tolerance and a response after sensitization. These studies in vitro demonstrate that this specificity, at least at the level of antigen recognition, is probably derived from different populations of cells, each responding to different antigens.     

Production of hemadsorption-negative areas by serums containing Australia antigen

Exposure of human Wi-38 cells to human serums containing Australia antigen, and presumably serum hepatitis virus, renders the cells refractory to infection by Newcastle disease virus as detected by the hemadsorption-negative plaque test for intrinsic interference. Induction of the Newcastle disease virus refractory state could be passed in cell culture with up to a 1 : 100,000 dilution of material obtained from cells "infected" with serums containing Australia antigen after filtration (0.45-microm pores) and heating to 60 degrees C for 1 hour. Human antiserums to the Australia antigen prevented induction of the Newcastle disease virus refractory state.     

苯磺隆农药标准品的制备研究

介绍了苯磺隆标准物质的提纯方法 ,以及纯化产品的定值以及定性鉴定方法。结果表明 :用该方法纯化的苯磺隆标样与国外进口标样纯度相近 ,能够作为商检以及残留分析用的标准物质     

苯噻酰草胺农药标准品的制备研究

研究了苯噻酰草胺标准物质的提纯、纯化产品的定值以及定性鉴定方法。结果表明:用该法纯化的苯噻酰草胺标样纯度与国外进口标样相近,能够作为商检以及残留分析用的标准物质。     

Induction of self-tolerance in T cells but not B cells of transgenic mice expressing little self antigen

Self-tolerance to a transgene-encoded protein, hen egg lysozyme, was examined in the T and B cell repertoires of a series of lines of transgenic mice that expressed different serum concentrations of soluble lysozyme. T cells were tolerant in all lines in which lysozyme was expressed irrespective of the antigen concentration, whereas B cell tolerance did not occur when the serum lysozyme concentration was less than 1.5 nanograms per milliliter (0.1 nM). Induction of elevated transgene expression could restore B cell tolerance. These findings support the hypothesis that autoimmune disease may in some instances arise through a bypass of T cell tolerance.