中国贝母属(Fritillaria)7种植物的核型研究

通过对7种国产贝母属（Fritillaria）植物的染色体核型进行观察和研究,报道了小白花贝母（F.albidoflora Duan&Zheng）、川贝母（F.cirrhosa Don）、伊贝母（F.pallidiflora Schrenk ex Fischer&Meyer）、华西贝母（F.sichuanica Chen）、托里贝母（F.tortifolia Duan&Zheng）、新疆贝母（F.walujewii Regel）、裕民贝母（F.yuminensis Duan）等7种植物的染色体数目及核型,其中3种为首次报道。结果显示,7种国产贝母属植物的核型均具有高度不对称性。此外,小白花贝母与已报道的黄花贝母（F.verticillata Willdenow）的核型存在明显差异,提示Flora of China将小白花贝母归并入黄花贝母的分类处理可能并不恰当,二者的关系需进一步研究。     

抑制O~6-甲基鸟嘌呤-DNA甲基转移酶活性与肿瘤细胞对亚硝脲药物敏感性关系的研究

80％以上的肿瘤细胞为O~6-甲基鸟嘌吟-DNA甲基转移酶(O~6-MT)活性较高的Mer~+型,能够修复亚硝脲药物(NU)造成的DNA烷化损伤,对NU不敏感。本实验证明,用0.75,0.50和0.25mmol/L甲基亚硝脲(MNU)分别处理Mer~+型的HeLaS3,SMMC-7721和表现Mer~-型特征的Cc801,均能明显降低细胞中O~6-MT活性,从而显著提高了三种细胞对嘧啶亚硝脲和双氯乙亚硝脲的敏感性,提示降低O~6-MT活性是使用NU对Mer~+型肿瘤进行有效治疗的前提。     

为害黄芪种子的广肩种子小蜂属四新种(膜翅目:广肩小蜂科)

据我们在北京和内蒙古等地多年研究表明,黄芪的植食性种子小蜂包括广肩小蜂科Bruchophagus属5种和金小蜂科Habrocytus属1种,为多种混合群体。我们通过大量标本的形态比较以及交配行为的观察,结合其生物学特性研究以及应用扫描电镜对其并胸腹节花纹的超微结构观察,鉴定出黄芪种子里有5种广肩种子小蜂,即黄芪种子小蜂Bruchophagus huonchi Liao et Fan及本文的4新种。     

^137Cs,^134Cs在人工海洋小生境中的行为

在自行建立的人工海洋小生境中,采用示踪法综合地研究~(137)Cs、~(134)Cs在人工小生境中的行为。结果表明,~(137)Cs和~(134)Cs具有共同的生理生态行为,并表现出相似的规律、沉积物对~(137)Cs、~(134)Cs的吸附能力甚低,~(137)Cs、~(134)Cs在海洋动物体内趋于全身性的分布。各主要生化物质均能检出~(137)Cs、~(134)Cs。排泄实验后,海洋动物的胃肠、肝(消化腺)~(137)Cs、~(134)Cs损失显著。沉积物表现为解吸-重吸附的过程。     

Caveolin, a protein component of caveolae membrane coats.

Caveolae have been implicated in the transcytosis of macromolecules across endothelial cells and in the receptor-mediated uptake of 5-methyltetrahydrofolate. Structural studies indicate that caveolae are decorated on their cytoplasmic surface by a unique array of filaments or strands that form striated coatings. To understand how these nonclathrin-coated pits function, we performed structural analysis of the striated coat and searched for the molecular component(s) of the coat material. The coat cannot be removed by washing with high salt; however, exposure of membranes to cholesterol-binding drugs caused invaginated caveolae to flatten and the striated coat to disassemble. Antibodies directed against a 22 kd substrate for v-src tyrosine kinase in virus-transformed chick embryo fibroblasts decorated the filaments, suggesting that this molecule is a component of the coat. We have named the molecule caveolin. Caveolae represent a third type of coated membrane specialization that is involved in molecular transport.     

Depolymerization of cortical microtubules is not a primary cause of chilling injury in corn (Zea mays L. cv Black Mexican Sweet) suspension culture cells

Cold-induced depolymerization of cortical microtubules were examined in suspension culture cells of corn (Zea mays L. cv Black Mexican Sweet) at various stages of chilling. In an attempt to determine whether microtubule depolymerization contributes to chilling injury, experiments were carried out with and without abscisic acid (ABA) pretreatment, since ABA reduces the severity of chilling injury in these cells. Microtubule depolymerization was detectable after 1 h at 4°C and became more extensive as the chilling was prolonged. There was little chilling injury after 1 d at 4°C in either ABA-treated or non-ABA-treated cells. After 3 d at 4°C, there was about 26% injury for ABA-treated and 40% injury for non-ABA-treated cells, as evaluated by 2,3,5-triphenyl-tetrazolium chloride reduction and by regrowth. After 1d at 4°C, less than 10% of cells retained full arrays of microtubules in both ABA-treated and non-ABA-treated cells, the remainder having either partial arrays or no microtubules. After 3d at 4°C, about 90% of cells showed complete or almost complete depolymerization of microtubules in both ABA-treated and non-ABA-treated cells. ABA did not stabilize the cortical microtubules against cold-induced depolymerization. In about 66% of ABA-treated cells and 57% of non-ABA-treated cells that had been held at 4°C for 3d, repolymerization of cortical microtubules occurred after 3h at 28°C. These results argue against the hypothesis that depolymerization of cortical microtubules is a primary cause of chilling injury.     

狭蚤属一新种记述(蚤目:多毛蚤科)

我们从陕西省南部大巴山(安康地区平利县千家坪林场,位于东经109°15′,北纬31°50′)采获一批蚤类标本,经鉴定其中有狭蚤属 Stenoponia Jordan et Rothschild,1911新种。根据其模式产地,命名为大巴山狭蚤,兹记述如下。 大巴山狭蚤 Stenoponia dabashanensis新种 鉴别特征 新种烦栉刺数和下唇须仅一节,与上海狭蚤 Stenoponia shanghaiensis Liu et Wu 1960 兰狭蚤 S. coclcstis Jordan et Rothschild, 1911 和短距狭蚤S. formozovi Ioff et Tiflov, 1934接近。但下列特征可以区别:1)第9腹板后臂近端部     

Biosynthesis of Prostacyclin in Rat Cerebral Microvessels and the Choroid Plexus

Abstract: Microvessels, predominantly capillaries, were isolated from rat cerebrum by a modification of published procedures. The morphology and purity of the preparations were monitored by light and electron microscopy and by enrichment in alkaline phosphatase, γ-glutamyl transpeptidase, and prostacyclin synthetase. A reversed-phase high-pressure liquid chromatographic method was used in the purification of prostaglandins after extraction from aqueous incubation solutions. Prostacyclin synthesis in brain is localized in cerebral blood vessels and capillaries. The endogenous biosynthetic capacity of the isolated cerebral capillary fractions for prostacyclin, measured as its chemically stable breakdown product, 6-keto-prostaglandin F_1α, was 11 ng/mg protein/10 min. Choroid plexus and intact surface vessels synthesized 6-keto-prostaglandin F_1α at 37 and 35 ng/mg protein/10 min, respectively. The prostacyclin-synthesizing enzyme of the cerebral capillaries also converted the exogenously added prostaglandin endoperoxides to 6-keto-prostaglandin F_1α. Comparison of the synthesis of prostaglandins 6-keto-F_1α, E₂, and F_2α showed that 6-keto-prostaglandin F_1α was the major prostaglandin formed in the microvessels, in the larger surface vessels, and in the choroid plexus. Prostaglandin D₂ was not detected. Prostacyclin synthesis by the cerebral vasculature is similar to that in other blood vessels and cultured human endothelial cells. Possible physiological roles of prostacyclin in the cerebral microvasculature are discussed with special regard to the autoregulation of cerebral blood flow.