Survival of genetically engineered Escherichia coli in natural soil and river water

Twelve derivatives of Escherichia coli strain HB101 which contained different sizes of plasmids ranging from 3.9 Kb to 48 Kb and encoding resistance to various antibiotics were used. When these organisms were introduced into natural river water, the population declined rapidly and by day 3, the majority (i.e. more than 99.9%) of them could no longer be detected on antibiotic-amended culture plates. If the river water was filter sterilized first, the added organisms maintained their population for up to 7 d without any significant decrease in numbers. Similar results were also observed in sterilized tap water or distilled water. This indicated that the disappearance of these organisms in the aquatic environment was caused mainly by biotic factor(s). The loss of the ability to grow in the presence of antibiotics by some of the E. coli was not observed unless they were allowed to grow in the antibiotic-free environment first. When the test organisms were added to natural silt loam, a large portion of the original population still remained viable after 16 d. There was no relationship between the percentage survival of E. coli in natural river water and the sizes of plasmid harboured. On the other hand, when these bacteria were added to natural soil, survival appeared to increase as plasmid size increased. and accepted 19 August 1989     

vif-negative human immunodeficiency virus type 1 persistently replicates in primary macrophages, producing attenuated progeny virus.

The vif gene of human immunodeficiency virus type 1 (HIV-1) is required for efficient infection of primary T lymphocytes. In this study, we investigated in detail the role of vif in productive infection of primary monocyte-derived macrophages (MDM). Viruses carrying missense or deletion mutations in vif were constructed on the background of the monocytotropic recombinant NLHXADA-GP. Using MDM from multiple donors, we found that vif mutants produced in complementing or partially complementing cell lines were approximately 10% as infectious as wild-type virus when assayed for incomplete, complete, and circularized viral DNA molecules by quantitative PCR amplification or for viral core antigen p24 production by enzyme-linked immunosorbent assay. We then determined the structure and infectivity of vif mutant HIV-1 by using MDM exclusively both for virus production and as targets for infection. Biosynthetic labeling and immunoprecipitation analysis of sucrose cushion-purified vif-negative HIV-1 made in MDM revealed that the virus had reduced p24 content compared with wild-type HIV-1. Cell-free MDM-derived vif mutant HIV-1 was infectious in macrophages as determined by the synthesis and maintenance of full-length viral DNA and by the produc- tion of particle-associated viral RNA, but its infectivity was approximately 2,500-fold lower than that of wild-type virus whose titer was determined in parallel by measurement of the viral DNA burden. MDM infected with MDM-derived vif-negative HIV-1 were able to transmit the virus to uninfected MDM by cocultivation, confirming the infectiousness of this virus. We conclude that mutations in vif significantly reduce but do not eliminate the capacity of HIV-1 to replicate and produce infectious progeny virus in primary human macrophages.     

蔷薇属38个野生种果实的维生素含量及其与分组的关系

对蔷薇属 (Rosa) 38个野生种果实 (以下简称蔷薇果 )的经济性状进行了分析 ,并测定了 VC、VE 和胡萝卜素等重要维生素的含量。蔷薇果 VC 含量在该属种间差异很大 ,以秦岭蔷薇 (R.tsinglingensis)的含量为最高 (2 576mg/ 1 0 0 g) ,德钦蔷薇 (R.deqenensis)的含量为最低 (49mg/ 1 0 0 g)。胡萝卜素含量种间差异明显 ,以软条七蔷薇 (R.henryi)的含量为最高 (1 9.2 4 mg / 1 0 0 g) ,黄刺玫 (R.xanthina)的含量为最低 (0 .0 6 mg/ 1 0 0 g)。 VE 含量种间差异较小 ,在 1 .34 mg/ 1 0 0 g(黄刺玫 )至 3.86 mg/ 1 0 0 g(硕苞蔷薇R.bracteata)之间。对蔷薇亚属 54种野生种果实重要维生素含量的统计分析表明 ,维生素含量与分组具有一定相关性 ,尤以 VC 含量与分组的相关性最为明显 ,桂味组和小叶组 Vc含量很高 (均值都高于 1 80 0mg/ 1 0 0 g) ;合柱组、月季组、木香组和硕苞组含量很低 (均值都在 30 0 mg/ 1 0 0 g以下 ) ,芹叶组除宽刺蔷薇 (R.platyacantha) VC含量很高外 ,其余种类含量都很低 (均值为 1 90 mg/ 1 0 0 g)。胡萝卜素含量与分组也具有一定相关性 ,桂味组、芹叶组、合柱组和硕苞组的胡萝卜素含量较高 ,均值在 6 mg/ 1 0 0 g以上 ;月季组、小叶组和木香组含量较低 ,均值在 0 .4mg/ 1 0 0 g以下。V     

RFLP-based maps of the homoeologous group-6 chromosomes of wheat and their application in the tagging of Pm12, a powdery mildew resistance gene transferred from Aegilops speltoides to wheat

Genetic maps of the homoeologous group-6 chromosomes of bread wheat, Triticum aestivum, have been constructed spanning 103 cM on 6A, 90 cM on 6B and 124 cM on 6D. These maps were transferred to a Chinese Spring (CS) x line #31 cross to locate a dominant powdery mildew resistance gene, Pm12, introgressed into line #31 from Aegilops speltoides. Pm12 was shown to lie on the short arm of translocation chromosome 6BS-6SS.6SL in line #31, but could not be mapped more precisely due to the lack of recombination between the 6S Ae. speltoides segment and chromosome 6B. Possible strategies to reduce the size of the alien segment, which probably encompasses the complete long arm and more than 82% of the short arm of chromosome 6B, are discussed.     

新疆六个民族指纹白线的调查研究The hand Print of Six Nationalities in Xinjiang

本文首次报道了新家6各民族6134人（南3181人、女2953人）的指纹白线出现频率。结果表明,白线频率女高于男,民族间亦有差异,其中维吾尔、哈萨克、鸟孜别克族频率接近。塔吉克族居住高寒高原地区,属白色人种,频率明显低于以上3个民族,锡伯族和汉族生活习惯近似,且高于以上4个民族,作者认为,白线出现频率的高低与种族、性别、年龄和群体生长环境及生活习惯有关。We’ve studied 6134 individuals (male 3181, fimale 2953) of six nationalities in Xinjiang.The result is that the white line of hand print is associated with rae,sex,age,grow environments of groups and life habbits.The ifference of races is:The appearant rates of white line of Weivuerite,Hasakese and Wuzibese are near,Tajike’s rate is lower than xiboman’s and han are higher than others.     

RFLP mapping of partially sequenced leaf cDNA clones in maize

We report here the results of mapping a set of 92 leaf cDNA clones in maize. The ends of each of these cDNA clones have previously been partially sequenced, and the sequence comparison has revealed the putative function for 28 clones. It is expected that the RFLP map developed using these expressed sequence tags will be of great importance for future maize genome analysis, such as for PCR-based gene mapping or gene function identification.Contribution from the Missouri Agricultural Experiment Station. Journal Series N. 12,019.     

Decoloration of azo dyes by three whiterot fungi: influence of carbon source

Two strains of Phanerochaete chrysosporium and a local isolate of white-rot fungus, if pre-cultured in a high nitrogen medium with glucose, could decolorize two azo dyes (Amaranth and Orange G) and a heterocyclic dye (Azure B). When starch was used in the pre-cultivation medium, decoloration of Orange G occurred if the medium also contained 12mM NH₄Cl, whether or not veratric acid was present. In medium containing 1.2mM NH₄Cl and veratric acid, greater decoloration occurred with one strain of P. chrysosporium and the local isolate. In preculture medium with cellulose and 1.2mM NH₄Cl, decoloration by the local isolate was enhanced but not that by the other strains.The authors are with the Department of Microbiology, Soochow University, Shih Lin, Taipei, Taiwan     

葡萄叶绿体rbcL基因的结构分析

以玫瑰香葡萄（Ｖｉｔｉｓｖｉｎｉｆｅｒａ Ｌ．）为材料,克隆了含有叶绿体ｒｂｃ Ｌ基因的３．１ ｋｂ Ｂａｍ ＨⅠ片段,构建了该基因的限制性酶切图谱,测定了该基因的核苷酸序列。所测的核苷酸序列总长度为２００４ ｂｐ,其中基因的编码区为１４２８ ｂｐ,编码一个含４７５ 个氨基酸的蛋白质,其分子量约为５３ ｋＤ;测定基因的５上游含启动子的部分共３５８ ｂｐ,包括－ １０ 区（ＴＡＡＡＡＴ）、－ ３５区（ＴＴＧＣＧＣ）和ＳＤ 序列（ＧＧＡＧＧ）;基因的３下游区共２１８ ｂｐ,含有３ 个转录茎环终止结构。玫瑰香葡萄ｒｂｃ Ｌ基因编码区的核苷酸序列与烟草、矮牵牛、菠菜、苜蓿、水稻和玉米之间的同源性分别为９１．５％ 、９１．４％ 、９０．２％ 、８９．８％ 、８６．３％ 和８４．５％ ;推导出的氨基酸序列的同源性分别为９２．２％ 、９１．６％ 、９２．２％ 、９３．７％ 、９３．５％ 和９０．１％ 。     

黑龙江依兰早第三纪植物群的古气候分析

对黑龙江依兰煤矿煤层间的大量植物叶痕化石研究表明：依兰植物群有蕨类植物２ 种,裸子植物１０ 种,被子植物５８ 种,分属３４ 科４６属。植物群可分为两个植物组合：一个是下煤层上顶板的矿页岩层化石的组合,称Ａ 段组合,时代为早始新世。植物种类丰富,含有较多常绿阔叶成分,属北亚热带的常绿阔叶和落叶阔叶、针阔叶混生林。通过植物叶相特征分析,其全缘叶比例为３８％ 。用气候诺模图得出其古气候为年均温１３．２℃,年温差２０℃;另一个植物组合是煤系地层之上,即上煤层顶部的油页岩层中的Ｂ段化石组合,时代为早渐新世。植物以落叶成分为主,属暖温带落叶阔叶林和针阔叶混生林。全缘叶比例为３０％ 。古气候年均温为１１℃,年温差２５℃。表明植物区系组成完全不同,显示出气候随时代发生了演变,而使区系逐渐发展到今日的寒温带气候和植被