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.     

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。     

Monoclonal antibodies specific for type 3 protein kinase C recognize distinct domains of protein kinase C and inhibit in vitro functional activity

Monoclonal antibodies (mAbs) which distinguish Type 3 protein kinase C (PKC) from Types 1 and 2 have been obtained from mice immunized with purified Type 3 PKC from rabbit brain cytosol. Most of these mAbs (seven out of eight) selectively recognize Type 3 versus Types 1 and 2 PKC in both enzyme-linked immunosorbent and immunoblot assays. Trypsin treatment of Type 3 PKC reduced the immunoreactivity with 82-kDa PKC and generated immunoreactive fragments of 45 and 35 kDa. The mAbs can be divided into two classes based on their ability to recognize the 45-kDa catalytic fragment (5/8) or the 35 kDa regulatory domain fragment (3/8). Each of the mAbs inhibits phosphorylation of histone or lipocortin by PKC, although the extent of the inhibition varied. Only those mAbs that recognize the 35-kDa regulatory domain inhibited phorbol ester binding. The inhibition of both kinase and binding activities by this group of mAbs was sensitive to the concentration of phospholipid used in the assay. This functional inhibition suggests that these mAbs may be useful for defining the phospholipid binding domain(s) of Type 3 PKC. The mAbs recognized 82-kDa PKC in a variety of cell types; the presence of smaller molecular weight fragments was not consistently found. Distinct immunofluorescence staining patterns were observed with mAbs directed toward different epitopes, suggesting that there may be heterogeneity in the subcellular localization of PKC. The type specificity of these mAbs will make them valuable tools for studying activation and regulation of Type 3 PKC in cell culture model systems.     

Studies on the phospholipid composition of pathogenic cell membranes of Mycoplasma hyopneumoniae

The membrane phospholipid and fatty acid compositions of Mycoplasma hyopneumoniae, a pathogen of porcine enzootic pneumoniae isolated in China, was studied by thin-layer chromatography and gas chromatography. The results showed that membrane phospholipids consisted predominantly of diphosphatidylglycerol. The percentage of C16 - C18 fatty acids comprised 79% of the total fatty acids, of which oleic acid as well as palmitic acid are the major fatty acids. Some differences were shown in fatty acid composition as compared with membranes of other species of Mycoplasma.     

体外分化的人体巨噬细胞抑制天然杀伤(NK)细胞的研究

本文继先前工作后,进一步应用正常健康人外周血单个核细胞(PBMNC)经塑料培皿粘附技术把单核细胞分离出来,经培养进一步纯化,随后动态观察培养0,2,4,6和8天的单核-巨噬细胞的形态变化和对新鲜分离同种异基因个体PBMNC中NK活性的影响。实验表明,体外分化6天和8天的巨噬细胞质/核比例和胞浆内空泡显著增加,细胞直径约为0天时的2倍。这些细胞和PBMNC之比为0.5:1时,引起了NK细胞活性的50%以上抑制(4小时~(51)Cr标记K 562肿瘤的同位素释放试验)。这种抑制效应不为过氧化氢酶(Catalase 4000单位/毫升)和前列腺素合成酶的抑制剂(Indom 1×10~(-5)M)所阻断。实验证明,同种异基因个体的NK细胞不能识别巨噬细胞表面抗原,从而排除了巨噬细胞和K562肿瘤抗原竞争的可能性。实验还表明,巨噬细胞对NK活性的抑制是不受HLA约束的。应用高频超声振荡破碎巨噬细胞膜方法和免疫调变技术进一步提示,人体巨噬细胞对NK活性的抑制与巨噬细胞体积无关,而与体外分化所赋有的固有特性和它们分泌的免疫调节分子有关。     

大萼香茶菜丁素的化学结构

从大萼香茶菜叶中又分得一个具有细胞毒活性的新的二萜类化合物,命名为大萼香茶菜丁素(macrocalyxin D)。根据光谱和化学数据鉴定其化学结构为[3]。     

四川自贡大山铺蜀龙动物群——简报Ⅴ 两栖类

本文对扁头中国短头鲵(新属新种) (Sinobrachyops placenticephalus gen. et sp. nov.) 的形态特征和分类位置进行简述.标本得自著名的恐龙化石产地——自贡大山铺,产出时代为中侏罗世.中国短头鲵是目前迷齿类中在地史上最年轻的一个属.它的发现使迷齿类在地球上生存时代的上限推移到中侏罗世.