Roles of phospholipase D in phorbol myristate acetate‐stimulated neutrophil respiratory burst

The phorbol myristate acetate (PMA) stimulated nutrophil respiratory burst has been considered to simply involve the activation of protein kinase C (PKC). However, the PLD activity was also increased by 10‐fold in human neutrophils stimulated with 100 nM PMA. Unexpectedly, U73122, an inhibitor of phospholipase C, was found to significantly inhibit PMA‐stimulated respiratory burst in human neutrophils. U73122 at the concentrations, which were sufficient to inhibit the respiratory burst completely, caused partial inhibition of the PLD activity but no inhibition on PKC translocation and activation, suggesting that PLD activity is also required in PMA‐stimulated respiratory burst. Using 1‐butanol, a PLD substrate, to block phosphatidic acid (PA) generation, the PMA‐stimulated neutrophil respiratory burst was also partially inhibited, further indicating that PLD activation, possibly its hydrolytic product PA and diacylglycerol (DAG), is involved in PMA‐stimulated respiratory burst. Since GF109203X, an inhibitor of PKC that could completely inhibit the respiratory burst in PMA‐stimulated neutrophils, also caused certain suppression of PLD activation, it may suggest that PLD activation in PMA‐stimulated neutrophils might be, to some extent, PKC dependent. To further study whether PLD contributes to the PMA stimulated respiratory burst through itself or its hydrolytic product, 1,2‐dioctanoyl‐sn‐glycerol, an analogue of DAG , was used to prime cells at low concentration, and it reversed the inhibition of PMA‐stimulated respiratory burst by U73122. The results indicate that U73122 may act as an inhibitor of PLD, and PLD activation is required in PMA‐stimulated respiratory burst.     

清香桂碱D和矮陀陀胺碱A,B的结构

本文报道从国产清香桂(Sarcococca ruscifolta)和金丝矮陀陀(Pachysandra axillaria)植物中分得的三个胺碱型新甾体生物碱清香桂碱 D 和矮陀陀胺碱 A、B 的化学结构,并首次归属了它们的~(13)C NMR 数据。     

贵州苏铁的核型分析

本文报道了贵州苏铁(Cycas guizhouensis)的染色体数目及核型,并与攀枝花苏铁(C.panzhihuaensis)、苏铁(C.revoluta)、华南苏铁(C.rumphii),拳叶苏铁(C.circinalis)和C.media等的核型进行了比较,讨论了苏铁属植物不同核型的进化趋势,提出了苏铁属植物的两种地理分布核型,即1.北回归线以北为K(2n)=22=2m+4sm+4st+12T包括贵州苏铁和攀枝花苏铁;2.北回归线及其以南为K(2n)=22=4m+8st+10T,包括苏铁、华南苏铁、拳叶苏铁和C.media。     

三种鱼类生长激素cDNA基因的结构比较研究

从厦门海区选取３种生长速度不同的鱼类,真鲈、高体Ｓｈｉ、褐菖Ｙｏｕ,由它们的脑下垂体中分别提取出总ＲＮＡ,用逆转录ＰＣＲ方法（ＲＴ－ＰＣＲ）扩增出生长激素ｃＤＮＡ,克隆到ｐＢｌｕｅｓｃｒｉｐｔ载体上的ＥｃｏＲＩ位点,并分别测定了这３种鱼的成熟生长激素ｃＲＮＡ序列。将由这３种序列推导出的氨基酸序列同已知的８种不同科鱼类的生长激素氨基酸序列进行比较,分析它们序列的同源性,结果表明它们间的同源性与这些鱼     

AST同工酶的琼脂糖凝胶电泳NBT显色法

分布于细胞内线粒体及细胞质中的天门冬氨酸氨基转移酶(AST·EC·2·6·1·1)是人血清中含有的两种同工酶,分别称为AST-m和AST-c同工酶.AST-c电泳迁移率介于血清α-球蛋白与β-球蛋白之间.AST-m电泳迁移率相似于γ-球蛋白,琼脂糖凝胶电泳固蓝B染色法对m-AST检出率较低.用NBT显色法则可得到较好效果.     

Further Evidence for Multiple Forms of an N-Methyl-d-Aspartate Recognition Domain in Rat Brain Using Membrane Binding Techniques

Abstract— Pretreatment with sulfhydryl-reactive agents, such as N-ethylmaleimide and p-chloromercuriphenylsul-fonic acid, invariably resulted in marked inhibition of the binding of dl -(E)-2-amino-4-[³H]propyl-5-phosphono-3-pentenoic acid ([³H]CGP 39653), a competitive antagonist at an N-methyl-d -aspartate (NMDA)-sensitive subclass of central excitatory amino acid receptors, in brain synaptic membranes extensively washed and treated with Triton X-100, but did not significantly affect the binding of L-[³H]-glutamic acid ([³H]Glu), an endogenous agonist. The pre-treatment was effective in reducing the binding of [³H]-CGP 39653 at equilibrium, without altering the initial association rate, and decreased the affinity for the ligand. Pretreatment with sulfhydryl-reactive agents also enhanced the potencies of NMDA agonists to displace [³H]-CGP 39653 binding and attenuated those of NMDA antagonists, but had little effect on the potencies of the agonists and antagonists to displace [³H]Glu binding. The binding of both [³H]CGP 39653 and [³H]Glu was similarly sensitive to pretreatment with four different proteases in Tritontreated membranes, whereas pretreatment with phospho-lipase A₂ or C markedly inhibited [³H]CGP 39653 binding without altering [³H]Glu binding. Moreover, both phospho-lipases not only induced enhancement of the abilities of NMDA agonists to displace the binding of [³H]CGP 39653 and [³H]Glu, but also caused diminution of those of NMDA antagonists. These results suggest that both sulfhydryl-reactive agents and phospholipases may predominantly interfere with radiolabeling of the NMDA recognition domain in a state favorable to an antagonist by [³H]CGP 39653, with concomitant facilitation of that in an agonist-preferring form by [³H]Glu. The possible presence of multiple forms of the NMDA recognition domain is further supported by these data.     

中国种子植物区系定量化研究 V．区系相似性

本文总结了应用相似系数即关联系数进行植物区系相似性分析的现状,指出了存在的问题．然后,从集合论角度讨论了区系相似性、相似关系及其相似系数的实质．作者以为在区系相似性分析中应用Ｒ．Ｒ．Ｓｏｋａｌ和Ｃ．Ｄ．Ｍｉｃｈｅｎｅｒ（１９５８）提出的简单匹配系数比较适宜,同时亦能避免以往区系相似性分析中缺乏可比性及某些“表相”相似等问题．最后,还提出了总体相似系数和类型相似系数二个新概念,以便按照吴征镒教授关于中国植物区系研究的学术思想统一研究各个不同地区植物区系的相似性．对此,作者用了６个区系实例进行了演算说明．