利用人摄金蛋白(METALLOTHIONEIN)启动子和牛乳突瘤病毒在哺乳动物细胞中表达乙型肝炎表面抗原

用人Metallothioenin-Ⅱ启动子、乙型肝炎表面抗原基因,SV40早期基因的编接位点和多聚A位点构成了表达组件,然后插入到经改造过的BpV-1质粒中。所得质粒pdMTsAg-5转染小鼠C127细胞得到转化克隆。Ausria Ⅱ检测证明13株中有12株能产生HBsAg。对其中一株进行HBsAg收率观察,隔天收获为292.6～525.8μg/升,每天收获为200.9～369.0μg/升,可连续收获60天以上。经重金属离子诱导后,收率增至583～854.4μg/升。培养液经超滤浓缩和两次密梯离心后,可集中为一个狭窄的峰,顶峰的Ausria Ⅱ cpm为1.05×10~7,密度为1.20g/ml。     

Comparison of Three 18F-Labeled Butyrophenone Neuroleptic Drugs in the Baboon Using Positron Emission Tomography

The butyrophenone neuroleptics spiroperidol, benperidol, and haloperidol were radiolabeled with fluorine-18 and studied in baboon brain using positron emission transaxial tomography (PETT). Pretreatment of the baboon with a high pharmacological dose of (+)-butaclamol reduced the specifically bound component of radioactivity distribution in the striatum to approximately the radioactivity distribution found in the cerebellum. Comparative studies of brain distribution kinetics over a 4-h period indicated that either [18F]spiroperidol or [18F]benperidol may be suitable for specific labeling of neuroleptic receptors. In an 8-h study with [18F]spiroperidol, striatal radioactivity did not decline, suggesting that spiroperidol either has a very slow dissociation rate or that it binds irreversibly to these receptors in vivo. [18F]Haloperidol may not be suitable for in vivo PETT studies, because of a relatively high component of nonspecific distribution and a faster dissociation from the receptor. Analysis of 18F in plasma after injection of [18F]spiroperidol indicated rapid metabolism to polar and acidic metabolites, with only 40% of the total radioactivity being present as unchanged drug after 30 min. Analysis of the metabolic stability of the radioactively labeled compound in rat striatum indicated that greater than 95% of [18F]spiroperidol remains unchanged after 4 h.     

Phytochrome control of its own accumulation and leaf expansion in tentoxin- and norflurazon-treated mung bean seedlings

Primary leaves of 4-day-old, dark-grown mung bean [ Vigna radiata (L.) Wilczek cv. Berken] seedlings were exposed to 24 h of white light (200 μmol m⁻² s⁻¹) which was terminated by a 15 min, phytochrome-saturating red or far-red light exposure. Phytochrome content (in vivo and in vitro) and leaf area were monitored during the subsequent dark period. Red light treatments resulted in lower phytochrome content and greater leaf expansion than did far-red treatments. Phytochrome accumulation and leaf expansion were less in norflurazon- (no carotenoids and very low Chl) than in tentoxin- (very low Chl) treated leaves. After 3 days of darkness, leaf expansion was about 25% greater and phytochrome content was about 50% less in red- than in far-red-treated leaves of all treatments. These effects generally took longer to develop in norflurazon- than in tentoxin-treated tissues. Norflurazon-treated tissues exposed to long white light periods apparently do not as accurately reflect phytochrome-controlled photomorphogenic events of green tissues as do tentoxin-treated tissues of mung bean seedlings.     

Structural similarities between corresponding heat-shock proteins from different eucaryotic cells

Effects of heat treatments on chick embryo fibroblasts, Drosophila embryonic cells, and human lymphoblastoid cells have been compared. Cells from all three species synthesize large heat-shock proteins (hsps) with Mr = 70,000 and 84,000-85,000. Different small hsps with Mr between 22,000 and 27,000 are made at high rates in heat-treated chicken and Drosophila cells but could not be observed in human cells. The structural features of the large hsps from cells of the different organisms were compared by three methods of peptide mapping, namely the examination of tryptic digests by two-dimensional thin layer chromatography or by high pressure liquid chromatography and of incomplete V8 digests by polyacrylamide gel electrophoresis. The Mr = 84,000-85,000 polypeptides from all three organisms are closely related, the chicken and human polypeptides having many peptides in common. The relationship between the Mr = 70,000 polypeptides of the different organisms appears to be less close; possible explanations for this latter result are discussed. Rates of synthesis of total as well as poly(A)+ RNA are much lower in heat-treated than in untreated cells of all three organisms. Heat treatments induce dramatic changes in the shape of chick embryo fibroblasts as seen by microscopic examination. Human lymphoblastoid cells do not show changes in shape.     

Analysis of human class I antigens by two-dimensional gel electrophoresis

Class I antigens were isolated by immunoprecipitation from cell extracts prepared from mitogenically stimulated and internally radiolabeled peripheral blood lymphocytes (PLBs). The precipitating antibodies used are monomorphic and recognize a determinant on the heavy chain of HLA-A, B, C antigens regardless of their allelic specificities when complexed with ₂m, or determinants on ₂m itself. Comparison of class I molecules isolated from 25 different homozygous typing cels (HTC) and analyzed by two-dimensional (2-D) gel electrophoresis allowed the identification of those HLA-A,13 locus specificities most common in the European Caucasoid population. Class I antigens isolated from HTC that are HLA identical are biochemically indistinguishable also. Evidence was obtained for the expression of additional class I antigens besides the HLA-A, B, C locus products: for some haplotypes, up to six class I genes may be active in mitogenically activated PBLs. No differences in molecular weight and isoelectric point of the class I heavy chains were observed between the antigens recognized by W6/32, the anti-heavy chain reagent, and anti- ₂m reagents. The nature of the mitogenic stimulus, i. e., pokeweed mitogen or phytohemagglutinin, was irrelevant with respect to the class I antigens isolated by this method. Using the HTCs as reference, a panel of HLA-B27 positive heterozygous cells was analyzed. Two types of HLA-B27 antigens, distinct by CML typing were represented. These two forms differed also in their biochemical properties. In addition, we obtained evidence for the existence of an A2 variant. This finding was likewise confirmed by CML typing.     

Comparison of stem-cell recovery in autoimmune and normal strains

The capacity of NZB stem cells to proliferate in vivo was evaluated in two systems which required repopulation of peripheral organs. In both types of depletion systems, stem-cell repopulation after cyclophosphamide treatment or adoptive transfer repopulation in lethally irradiated hosts, it was found that NZB stem cells were hyperproliferating. The increase in proliferating cells was most pronounced in the spleens of NZB mice treated with high-dose cyclophosphamide and in lethally irradiated F₁ mice reconstituted with NZB T-cell-depleted bone marrow. Thus, upon a stimulus to repopulate, NZB marrow stem cells will hyperproliferate in peripheral organs resulting in an increase in cell number. The abnormality in the marrow cells can be observed in young NZB mice when their marrow cells are in an environment which requires recovery and division.     

Comparison by Gas-Liquid Chromatography of the Fatty Acids of Mycobacterium avium and Some Other Nonphotochromogenic Mycobacteria

Fifty-eight strains of nonphotochromogenic mycobacteria representing nine different serotypes were studied, including 38 strains of Mycobacterium avium and 20 strains of Battey bacilli. The lipids were extracted from whole cells, saponified with potassium hydroxide, and esterified with diazomethane. The fatty-acid profiles determined by gas-liquid chromatography included saturated fatty acids ranging from C(8) to C(24), plus some unsaturated analogues and a branched-chain acid. No consistent differences in the fatty-acid profiles were observed between strains of M. avium and Battey bacilli. Quantitative differences in the means (significant at P < 0.01) were observed in the relative amounts of 14:0, 16:1, 18:0, 18:1, and a branched-chain acid among strains of the same serotype. We were unable to differentiate the fatty-acid profiles of recently isolated strains or those maintained in culture for more than 2 years.