刺果番荔枝中的番荔枝内酯

从刺果番荔枝（Ａｎｎｏｎａ ｍ ｕｒｉｃａｔａ Ｌ．）的种子中分离到３ 个单四氢呋喃型番荔枝内酯类化合物,用波谱方法鉴定为海南哥纳香甲素（ｈｏｗ ｉｉｃｉｎ Ａ, Ｓ１３）、乙素（ｈｏｗ ｉｉｃｉｎ Ｂ, Ｓ５）和新化合物４－去氧海南哥纳香乙素（４－ｄｅｓｏｘｙｈｏｗ ｉｉｃｉｎ Ｂ, Ｓ２）。     

Somatic hybridization between Citrus reticulata and Citropsis gabunensis through electrofusion

Protoplasts from embryogenic calli of Citrus reticulata Blanco cv. Ponkan and Citropsis gabunensis (Engl.) Swing. & M. Kell (Cabon Cherry Orange), were isolated and fused using electric current. Maximum fusion frequency was obtained with AC at 75 kV/cm (1.0 MHz) for 15 s, followed by DC square-wave pulses at 1.25 kV/cm for 40 s. Fusion-treated protoplasts were cultured on MT medium containing no growth regulators, solidified with 0.6% Bacto Difco agar. Protoplast-derived calli were proliferated on MT medium containing 1 mg/l zeatin and 0.9% agar. A total of 31 lines of somatic hybrid calli were obtained by screening on the basis of chromosome count and isozyme analysis. The somatic hybrids were tetraploid (2n=36). Plants were regenerated from the calli via somatic embryogenesis. The somatic hybrid plants exhibited morphological characteristics intermediate to the parental plants.Abbreviations 2,4-D 2, 4-dichlorophenoxyacetic acid - BA 6-benzylaminopurine - MT Murashige and Tucker (1969) - PEG polyethylene glycol - AC alternating current - DC direct current     

大血藤科植物的分类学研究

作者对大血藤科植物的花性、叶片内部结构形态、花粉形态、染色体核型及过氧化物酶和脂酶同工酶进行了比较研究,结果表明：１）大血藤科植物外形上的两性花,其雄蕊的形态退化、花药始终不开裂,为功能上的雌花,因此其花为单性,同株,同序或异序;１２）首次指出大血藤属植物的染色体数为２ｎ＝２ｘ＝２２,属小型染色体,与木通科植物２ｎ＝２ｘ＝３２、３０、２８的染色体数明显不同,支持Ｓｔａｐｆ（１９２６）将其从木通科分出另立为科的观点;３）单叶和复叶可出现于同一植株上,而且在叶片内部结构、花粉形态、染色体核型、过氧化物酶及脂酶同工酶等性状上,大血藤与单叶血滕间均无实质性的差异,因此将单叶血藤归并于大血藤中。     

The loss of culturability by Escherichia coli cells in seawater depends on availability of phosphate ions and phosphate transport systems

Using strains with or without the PhoE porin or different components of the phosphate regulon, we determined that maintenance of the culturability of Escherichia coli in seawater depended significantly on the presence of structures allowing access of phosphate ions to the periplasm, then to the cytoplasm of cells. Cells totally deprived of the two main phosphate transport systems (Pit, Pst) exhibited the highest loss of culturability. Most of this effect resulted from the loss of the high-affinity Pst system, and more specifically that of the periplasmic phosphate-binding protein PhoS. Survival was enhanced in seawater supplemented with phosphate (0.5 mm), whether or not these structures were present. From an ecological point of view, it is assumed that the presence of phosphate ions, even at low concentrations, can influence the behavior of E. coli cells in seawater. Offprint requests to: M.J. Gauthier     

豇豆单孢锈菌中病毒样颗粒中双链RNA的存在

从北京西郊清华园附近田间豇豆上采集的豇豆单孢锈菌(Uormyces vignal Barcl)夏孢子。萌发后提取双链RNA,电泳分析可测出300—8000碱基对的三组双链RNA。从萌发的孢子中通过差迷离心提取病毒样颗粒,可获得二种类型的病毒样颗粒,一种直径为35—40nm的等轴颗粒。另一种为长短不等的棒状颗粒,用提纯物提取核酸电泳分析与直接从孢子中提取的双链RNA有相同的核酸带,从而证明这些双链RNA存在于病毒样颗粒中。     

RGDS肽对大鼠主动脉球囊内膜剥脱后血管壁增殖的影响

在大鼠主动脉球囊内膜剥脱术后血管壁细胞过度增殖模型上,用合成的血小板膜纤维蛋白原受体（ｇｌｙｃｏｐｒｏｔｅｉｎⅡｂ／Ⅲａｃｏｍｐｌｅｘ,ＧＰⅡｂ／Ⅲａ）拮抗剂ＲＧＤＳ（Ａｒｇ－Ｇｌｙ－Ａｓｐ－Ｓｅｒ,５０μｍｏｌ·ｋｇ－１·ｄ－１）治疗可有效地抑制损伤血管壁的细胞计数增加和内膜增厚以及血管平滑肌细胞增殖,显著降低其血管组织３Ｈ－ＴｄＲ和３Ｈ－Ｌｅｕ的参入增加程度。实验结果提示ＲＧＤＳ肽作为血管成型术的辅佐剂,对于防治血管再狭窄可能具有潜在的临床应用前景。     

空篷和正常板栗果实发育过程中氨基酸、碳水化合物变化规律的回归分析

本文研究了空篷和正常板栗果实发育过程中的氨基酸和碳水化合物的含量变化,并运用回归分析的方法探讨两者的变化规律及其差异．结果表明：在板栗不同发育时期,子房内氨基酸和淀粉含量变化具有规律性,并得到相关极显著的回归方程,空篷与正常栗具明显示的差异;总苞内除正常栗氨基酸含量得到相关极显著的回归方程外,其它的含量变化回归分析均未得到显著水平,空篷栗与正常栗的差异亦不显著．     

麻疹疫苗生产连续培养多次收获工艺研究

本研究对连续培养多次收获工艺用于麻疹疫苗生产的可行性、疫苗维持液保护剂、冻干保护剂及冻干过程等进行了大量反复试验,结果表明在现行条件下,本生产工艺具有重复性好、成本低、投入产出率高、易于质量控制等优势。对本工艺生产疫苗进行全面检定,表明成品滴度和稳定性试验指标等均高于９０版《生物制品规程》要求,并在试验基础上制定出了生产工艺流程。     

硅藻土在青霉素G酰化酶提纯中的应用

国产硅藻土经氢氧化铵处理后可用于从发酰液中直接取青霉素Ｇ酰化酶,平均吸附量为９０Ｕ／ｇ。吸附的酶可用２２％硫酸铵－０．３ｍｏｌ／ＬＰＢＳ（ｐＨ８．０）溶液洗脱。平均比１８Ｕ／１８Ｕｍｇ蛋白（ＮＩＰＡＢ法）。硅藻土可反复使用。苯乙酰胺－Ｓｅｐｈａｒｏｓｅ４Ｂ树脂可对酶作进一步的纯化。     

钙／钙调素依赖性蛋白激酶对17．7kD和6kD胰腺蛋白的磷酸化

本文报导了胰腺提取物中两种可被钙／钙调素依赖性蛋白激酶磷酸化的热稳定蛋白。ＳＤＳ－ＰＡＧＥ测定其表观分子量分别为１７．７ｋＤ和６ｋＤ。经钙／钙调素依赖性蛋白激酶磷酸化后,其最大磷酸参入量为８．８μｍｏｌ／ｇ蛋白。同时磷酸化作用导致１７．７ｋＤ蛋白在ＳＤＳ－ＰＡＧＥ中迁移率发生变化。本文还进一步分析了各种阳离子对磷酸化的影响,并对此两种蛋白可能具有的生理功能进行了初步探讨。