天然抗氧化剂丹参酮Ⅱ—A对肝细胞脂质过氧化产物与DNA相互作用的影响

［３Ｈ］花生四烯酸标记的肝细胞,经ＦｅＣｌ２－ＤＴＰＡ启动脂质过氧化后,细胞ＤＮＡ出现放射性,并随保温时间增加而逐渐增高,表明在细胞内脂质过氧化产物与ＤＮＡ发生相互作用,生成了一种ＤＮＡ加成物,经测定它具有特征荧光光谱,显示较低的增色效应和Ｔｍ值。用高度敏度荧光图象显微镜直接观察发现丹参酮Ⅱ－Ａ经细胞摄取后主要滞留在细胞膜与胞浆中。它能有效地抑制细胞脂质过氧化,减少脂质－ＤＮＡ加成物的产生,并阻止了细胞存活率和Ｏ６甲基鸟嘌呤转移酶活性的降低,其抑制率与ＶｉｔＥ,ＢＨＴ相近,但显著高于ＮａＮ３,甘露醇和ＳＯＤ。上述结果提示丹参酮Ⅱ－Ａ是一种新的有效的细胞内脂质过氧化产物与ＤＮＡ相互作用的抑制剂。它对ＤＮＡ的保护作用可能是通过清除脂类自由基而阻断脂质过氧化的链式反应,抑制ＤＮＡ加成物的生成,从而减少了细胞毒性。     

达斡尔族成人的体格,体型及半个多世纪来的变化

对内蒙古自治区莫力达瓦族３５３名（男１８７,女１６６）２０－６０岁达斡尔族进行了活体观察与测量,总结了达斡尔族的体格特征和类型。并在城乡之间和与半个世纪以前同一地区达斡尔族的体质资料之间进行了比较。     

山西星粉蚧属二新种记述（同翅目：蚧总科：粉蚧科）

本文记述采自中国山西的星粉蚧属２新种,模式标本保存在山西农大蚧虫研究中心。１．无脐星粉蚧Ｈｅｌｉｏｃｏｃｃｕｓａｃｉｒｃｕｌｕｓ,新种（图１）本新种与Ｈ．ＢａｏｔｏｕｉＴａｎｇ,１９８８为本属中无腹脐者。两种的区别在于后种星管腺２种,且多;而新种星管腺１种,且少。正模♀,蒿（Ａｒｔｅｍｉｓｉａｓｐ．）,山西沁水,１９９５－Ⅶ－２１,武三安采;副模１２♀♀,同正模;５♀♀,青蒿（Ａｒｔｅｍｉｓｉａａｐｉａｃｅａ）,其它同正模２．苜蓿星粉蚧Ｈｅｌｉｏｃｏｃｃｕｓｍｅｄｉｃａｇｉｃｏｌａ,新种（图２）本新种与Ｈ．ｐａｖｌｏｖｓｋｉＢｏｒｃｈｓｅｎｉｕｓｅｔＴｅｒｅｚｎｉｋｏｖａ,１９５９相近,其区别在于新种星管腺少,只在后体部存在,而后种星管腺多,在体背缘成纵列。正模♀,苜蓿（Ｍｅｄｉｃａｇｏｓａｔｉｖａ）,山西沁水,１９９５－Ⅶ－２２,武三安采;副模６♀♀,同正模     

蛇胆祛痰作用的实验研究

用２组小鼠,每组１０只。实验组用蛇胆酒灌胃,对照组用生理盐水灌胃,均以气管内酚红排泄法观察。结果示,酚红排泄量实验组比对照组明显为高。说明蛇胆确有增加小鼠气管分泌,稀释痰液的作用     

鹅掌楸雌配子体败育对生殖的影响

胚珠和雌配子体败育是限制鹅掌楸生殖成功的一个重要因素。中国东部和西部鹅掌楸种群在雌配子体发育的各阶段上的败育程度有差异,以西部种群的发育较好。西部分布区较合适的生境促进了胚囊的发育,一定温度和湿度的环境可以活化珠心细胞输送营养物质供给雌配子体发育,提高受精和结籽的能力     

稻茎毛眼水蝇幼虫田间分布型及抽样技术

根据14丘稻田稻茎毛眼水蝇幼虫调查资料．对其幼虫分布型进行了分析。结果表明;用I、CAm／m、Iσ四种聚集指标法测定,64．3％的田块呈随机分布．28．4%为均匀分布．7．3%为聚集分布。用Iwao平均拥挤度和Taylor幂法则测定．其田间分布型符合随机分布。用频次拟合法测验,50%的田块同时符合渡松、奈曼和负二项分布三种分布型;35．7%的田块同时符合2种分布型。根据该虫田间分布型的特点．制定了相应的序贯抽样技术。     

光亲和标记鉴定玉米根脱落酸结合蛋白

光亲和标记鉴定玉米根脱落酸结合蛋白吴忠义,陈珈,朱美君（北京农业大学生物学院,１０００９４）关键词结合蛋白;光亲和标记;ＡＢＡ;受体;微粒体脱落酸（ＡＢＡ）作为一大类植物激素,在高等植物的生长发育以及对逆境的适应过程中发挥着重要作用。在探讨激素作用的...     

Substance budgets of an upland catchment: the significance of atmospheric phosphorus inputs

1. Precipitation inputs and outflow stream outputs are presented for 1993 in an upland lake and catchment system on the Antrim Plateau, Northern Ireland. 2. Phosphorus, potassium, chloride and possibly sulphate behaved conservatively inputs were approximately balanced by outputs. Combined nitrogen outputs were very much less than inputs, whereas there was a net export of calcium, magnesium, sodium and silica from the catchment. 3. Precipitation phosphorus inputs (22 kg P km^?2yr^?1) are compared with literature data and are shown to be near the median value. 4. The phosphorus budget is discussed in relation to the fact that there are few oligotrophic lakes in Northern Ireland. It is suggested this is due to the rainfall inputs, low phosphorus retention by the catchment and rapid flushing rates in the lakes.     

Two-dimensional crystallization of avidin on biotinylated lipid monolayers.

Two-dimensional crystals of avidin were obtained on mixed lipid monolayers containing biotinylated lipids (N-biotinyl-dipalmitoyl-L-alpha-phosphatidyl ethanolamine and dioleoyl phosphatidyl choline) by specific interaction. Image analysis of electron micrographs of these crystals revealed p2 symmetry with the unit cell parameters a = 66 +/- 2 A, b = 68 +/- 1 A, and gamma = 121 +/- 4 degrees. The projection map showed, at a resolution of about 27 A, that the four subunits within one avidin molecule are separated into two parts. Comparison between avidin and streptavidin reveals that avidin molecule binds to the lipid monolayer in an orientation similar to that of streptavidin.