Gene identification in a complex chromosomal continuum by local genomic cross-referencing

Most higher plants have complex genomes containing large quantities of repetitive DNA interspersed with low-copy-number sequences. Many of these repetitive DNAs are mobile and have homology to RNAs in various cell types. This can make it difficult to identify the genes in a long chromosomal continuum. It was decided to use genic sequence conservation and grass genome co-linearity as tools for gene identification. A bacterial artificial chromosome (BAC) clone containing sorghum genomic DNA was selected using a maize Adh1 probe. The 165 kb sorghum BAC was tested for hybridization to a set of clones representing the contiguous 280 kb of DNA flanking maize Adh1. None of the repetitive maize DNAs hybridized, but most of the low-copy-number sequences did. A low-copy-number sequence that did cross-hybridize was found to be a gene, while one that did not was found to be a low-copy-number retrotransposon that was named Reina. Regions of cross-hybridization were co-linear between the two genomes, but closer together in the smaller sorghum genome. These results indicate that local genomic cross-referencing by hybridization of orthologous clones can be an efficient and rapid technique for gene identification and studies of genome organization.     

鱼腥藻1017株的混合营养型生长

鱼腥藻１０１７株混合营养型生长有其特点,外源葡萄糖对生长的刺激不仅在低光强（８００ｌｘ）,而且在高光强（７０００ｌｘ）也表现出来。其混合营养型生长速率在８００－７０００ｌｘ范围内随光照强度的增加而增加,在葡萄糖浓度５－２０ｍｍｏｌ／Ｌ范围内随外源葡萄糖浓度增加而增加。鱼腥藻１０１７株混合营养型生长与光能自养生长相比,生长速率明显提高,对数生长期延长,收获物浓度显著增高,生物量显著提高。     

视黄醇结合蛋白的结构与功能

视黄醇结合蛋白（RBP）是视黄醇转运的载体蛋白,作为结合小分子流水物质的载体蛋白家族（lipocalin）的一个重要成员,其结构与功能的研究正受到国外学者的重视,文章介绍了视黄醇结合蛋白的性质、结构研究进展,讨论了视黄醇结合蛋白与前蛋白和受体相互作用的位点和结构特点．     

邻二氮菲－Fe2＋氧化法检测H2O2／Fe2＋产生的羟自由基

报告检测H₂O₂/Fe^2＋所产生羟自由基的新方法. 羟自由基氧化反应后, 邻二氮菲-Fe^2＋的A₅₃₆明显下降, 且△A₅₃₆与邻二氮菲, FeSO₄及H₂O₂呈量效关系, 随反应时间延长, △A₅₃₆依幂函数规律上升. 此法试验结果表明, 甘露醇, 抗坏血酸及硫肥清除羟自由基作用呈明显的量效关系.     

宜昌大老岭种子植物区系研究

大老岭有野生种子植物１２２科４３５属８５６种。对本区科、属和种进行了统计与分析,结果表明,该地区的植物区系性质明显是温带性,且以北温带成分为主,地理成分复杂,仅属就有１３个分布区类型和１７个变型,地理联系广泛,具有古老性强和特有现象不很突出的特点。     

H－ras在颊粘膜正常、良性、癌前及恶性变上皮中的表达：免疫组织化学定量研究

本文通过建立图象分析方法对免疫组织化学反应结果进行定量,检测观察Ｈ－ｒａｓ在口腔颊粘膜上皮在正常（Ｎ）、慢性炎症（ＩＦ）、癌旁上皮（ＥＡＣ）和鳞癌（ＳＣＣ）的变化过程中的表达并进行分析。结果显示Ｈ－ｒａｓ在ＳＣＣ组中,以中等分化的ＳＣＣ无论是Ｈ－ｒａｓ表达的量还是细胞阳性率都较高。此外,组织学观察显示,Ｈ－ｒａｓ在处于分化末期但尚未角化的正常上皮细胞中有较高的表达。本文结果显示了Ｈ－ｒａｓ的过表达与上皮细胞的会化程度密切相关。本研究还显示,所采用的阳性区域透光值、平均总透光值及阳性反应区域与阴性反应区域比值可靠并有相关性。这进一步说明了用免疫组化定量方法检测Ｈ－ｒａｓ癌基因表达的精确和可靠性。     

人重组GM－CSF／HAS－D3嵌合蛋白（GM－HSA）在大肠杆菌中的表达及其产物稳定性的研究

将人粒细胞－巨噬细胞集落刺激因子（ＧＭ－ＣＳＦ）和人血清白蛋白第三功能区（ＨＡＳ－Ｄ３）的基因串联后,在Ｅ．ｃｏｌｉ中获高效表达,表达量占菌体蛋白的３２．６％．利用ＴＦ－１体外细胞活性测定表明,ＧＭ－ＨＳＡ的活性单位为１．０４×１０~６Ｕ／ｍｇ,虽然其比活性低于ＧＭ－ＣＳＦ,但比后者具有更高的体外热稳定性和储藏稳定性．     

IN VIVO EFFECTS OF CARDIOTROPHIN-1

Cardiotrophin-1 (CT-1) is a recently discovered cytokine that was isolated based on its ability to induce cardiac myocyte hypertrophy in vitro. In this study, the effects of chronic administration of CT-1 to mice (0.5 or 2 μg by intraperitoneal injection, twice a day for 14 days) were determined. A dose-dependent increase in both the heart weight and ventricular weight to body ratios was observed in the treated groups. The body weights of the animals were unaffected. These results indicate that CT-1 can induce cardiac hypertrophy in vivo. CT-1 was not specific for the heart, however. It stimulated the growth of the liver, kidney, and spleen, and caused atrophy of the thymus. CT-1 administration also increased the platelet counts by 70%, with no change in mean platelet volume. Red blood cell counts were increased in the treated animals, and there was a concomitant increase in haemoglobin concentration. Thus, CT-1 has a broad spectrum of biological activities in vivo. This observation is consistent with previous in-vitro findings showing that the mRNA for CT-1 is expressed in several tissues, and that CT-1 can function through binding to the leukaemia inhibitory factor (LIF) receptor and signalling through the gp130 pathway.     

旱地玉米农田棵间蒸发研究

采用中子微区模拟装置测量旱地玉农田棵间蒸发,实验表明,本实验装置实用可行。晋西棵间蒸发量占降水量（５１０ｎｍ）的５５％以上,棵间蒸发与蒸散的比值同时叶面积指数呈反相关,玉米产量与作物蒸腾呈正相关。