猪肺炎支原体膜上ATP酶生化性质的研究

猪肺炎支原体膜上ATP酶为Mg~(2+)激活,乌巴因不抑制。DCCD和寡霉素对该酶也无抑制作用,只有NBD与Quercetin才有一定的抑制效果。用梯度凝胶电泳可获均一的具有活性的酶蛋白带。     

Comparative analysis of glycoprotein and glycolipid composition of virulent and avirulent strain membranes ofMycoplasma hyopneumoniae

The glycoproteins and glycolipids from membranes of virulent strain Z and avirulent strain M ofMycoplasma hyopneumoniae have been compared. The proteins and the glycoproteins were identified by SDS-polyacrylamide gel electrophoresis and concanavalin A-biotin labeling, respectively. The membrane preparation contained approximately 34 protein bands with molecular weights between 20 KD and 100 KD. The concanavalin A-biotin system reacted with a glycoprotein of a molecular weight of approximately 28,000 from avirulent strain M and did not react with the correspondent band from virulent strain Z. The membrane glycolipids of both strains consisted of monogalactosyldiacylglycerol (MGDG) and digalactosyldiacylglycerol (DGDG), and the percentages of 160, 180, and 181 fatty acids comprised more than 80% of the total fatty acids of membrane glycolipids. The 180 fatty acid of MGDG in avirulent strain M was twofold higher than that of virulent strain Z.     

Expression of an enhancer-binding protein in insect cells transfected with the Autographa californica nuclear polyhedrosis virus IE1 gene.

The baculovirus Autographa californica nuclear polyhedrosis virus contains an element known as homologous region 5 (hr5) which is an enhancer of delayed-early viral gene expression. To begin to identify proteins that interact with hr5, DNA-protein interactions were analyzed by using extracts from Spodoptera frugiperda cells and a fragment of DNA containing the left half of the hr5 enhancer. This 252-bp DNA fragment contains two copies of a 30-bp direct repeat (DR30) and two copies of a 24-bp imperfect palindrome contained within a 60-bp direct repeat (DR60). Extracts prepared from normal S. frugiperda cells and cells transfected with pUC8 lacked enhancer-binding proteins. However, when gel shift assays were performed with extracts from cells transfected with a plasmid containing the viral trans-activator IE1 gene, two DNA-protein complexes were formed. Both DNA-protein complexes were specifically inhibited by competition with a 60-bp oligonucleotide corresponding to DR60 but not by competition with a different oligonucleotide corresponding to DR30. Formation of the two complexes did not appear to involve cooperative interactions between binding proteins. When DR60 was used as a probe, a single complex was formed. To measure the enhancer activity of DR60, a reporter plasmid was constructed that contained DR60 cloned upstream of the reporter chloramphenicol acetyltransferase gene under the control of the delayed-early 39K promoter. Transient expression analysis indicated that the oligonucleotide increased expression of this gene 300-fold over the level obtained in the absence of any enhancer sequences.     

Monoclonal Antibodies against Apple 1-Aminocyclopropane-l-Carboxylate Synthase

1-Aminocyclopropane-l-carboxylate (ACC) synthase from applefruits was purified over 5,000-fold by conventional column chromatography.By immunizing mice with this partially purified enzyme preparation,8 hybridoma lines producing monoclonal antibodies against appleACC synthase were isolated. While all 8 clones immunoprecipitatednative ACC synthase, only two clones recognized the putative(48 kDa) ACC synthase on Western blots. When a partially purifiedACC synthase preparation was incubated with S-adenosyl-L-[carboxyl-¹⁴C]methionine(AdoMet), only one radioactive protein of 48 kDa was detectedon sodium dodecyl sulfate-poly-acrylamide gel electrophoresis.This radioactive protein was specifically immunoprecipitatedby the monoclonal antibodies, indicating that apple ACC synthaseis specifically radiolabeled by its substrate AdoMet, as istomato ACC synthase. Thus, the monoclonal antibodies recognizedboth native and AdoMet-inactivated forms of ACC synthase. Whilethese antibodies failed to im-munoprecipitate ACC synthase isolatedfrom ripe tomato fruits, ripe avocado fruits or auxin-treatedmungbean hypocotyls, they were effective in immunoprecipitatingthe enzyme isolated from ripe pear fruits. (Received August 11, 1990; Accepted October 17, 1990)     

Simultaneous identification of estrogen and progesterone receptors by HPLC using a double isotope assay.

Polymorphism of estrogen (ER) and progestin receptors (PR) was analyzed simultaneously using high performance hydrophobic interaction chromatography (HPHIC). HPHIC was used previously to characterize four ER isoforms [Hyder et al., J. Chromat. 397 (1987) 251] based on retention times on Synchropak propyl (100 x 6 mm) HPLC columns (Synchrom, Inc.). ER and PR were prepared from human breast cancer. ER was labeled with 3 nM of either [3H]estradiol-17 beta ([3H]E) or [125I]iodoestradiol-17 beta ([125I]E) while PR was associated with 5 nM of either [3H]R5020 ([3H]R) or [125I]iodovinylnortestosterone ([125I]V). ER was resolved by HPHIC into isoforms MI (Rt = 11 min), I(Rt = 16 min), and II (Rt = 24 min). Isoforms I and II each accounted for ca 45% of specific binding. PR separated into isoforms MI (Rt = 14 min) and I (Rt = 21 min, 80% of specific binding) when eluted with the same gradient used for ER chromatography. Upon inclusion of 10 mM molybdate ER resolved into isoforms MI and MII (Rt = 16 min) and PR into isoforms MI and I (here however isoform MI represented 80-95% of specific binding). Elution patterns were preserved with different batches of stationary phase suggesting the integrity of the isoform distribution. HPLC profiles of ER isoforms labeled with earlier [125I]E or [3H]E were identical as were PR isoform profiles labeled with either [3H]R or [125I]V. Pairs of 125I- and 3H-labeled ligands were used in either combination to monitor ER and PR profiles simultaneously. Isoforms analyzed in 50 biopsies gave reproducible retention times, however the ratio between I and II for ER and MI and I for PR varied. This method allows rapid, simultaneous monitoring of the chromatographic behavior of ER and PR isoforms or other associating proteins or nucleotides. One may now better elucidate their interrelationship as it relates to the hormone-response mechanism.     

湖南邵东中泥盆统棋梓桥组层孔虫生物群及其生态环境

湖南中部泥盆纪地层和生物礁相当发育。湖南邵东中泥盆世棋梓桥期的泥质石灰岩中层孔虫广泛分布,本文共描述邵东廉桥马鞍山棋梓桥期层孔虫12属18种,其中Stromatopora wenshanensis为一新名,代替1982年根据一个云南标本定名为Stromatopora irregularis的种名。 马鞍山礁是—发育在海底平台上的厚度稍有变化的层状礁,马鞍山礁的沉积相变化过程,是由近岸浅海到展状礁普遍发育的开阔台地,再到封闭或半封闭的泻湖或潮坪环境。生物组合和沉积物也随沉积环境的变化而发生相应的变化。     

石灰菌代谢产物的化学研究(Ⅰ)

从石灰菌(Lactarius hysginus Fr.)提取物的中性部分,分离得到六个化合物,经物理常数和光谱分析,鉴定为麦角甾醇(A)、硬脂酸甲脂(B)、N-苯基-2-萘胺(C)、24E-麦角甾7,22-二烯-6-酮一3β,5α-二醇(D)、庚酰胺(E)、24E-麦角甾-7.22-二烯-3β,5α,6β-三醇(F),其中化合物D作为天然产物尚未见文献报道。     

黄淮海平原高产田作物群体结构特征

本文利用实测资料分析了高产田作物群体结构特征。精播高产栽培麦田春季最大蘖数12×10~6/ha,群体最大叶面积指数5.5—6.0,成穗4.5—5.25×10~6/ha。传统高产栽培麦田春季最大蘖数15—18×10~6/ha,群体最大叶面积指数6.0—6.5,成穗6.0—7.5×10~6/ha。小麦营养生长与生殖生长期叶日积比,精播高产栽培麦田是1∶0.89,传统高产栽培麦田为1∶0.73。夏玉米种植密度主要受叶倾角的影响。紧凑型玉米品种的叶倾角大于65°,种植密度7.5—8.25×10~4/ha;平展型玉米品种的叶倾角小于50°,种植密度5.25—6.0×10~4/ha。