In vivo incorporation of14C-phenylalanine into ascidian tunichrome

Ascidia ceratodes exposed to¹⁴C-phenylalanine in the surrounding seawater incorporates the radiolabel into newly biosynthesized tunichrome molecules. Radioactivity can be detected in tunichrome extracted from circulating blood cells within one day following initial exposure to the radiolabel; weak activity (4 Ci/mol tunichrome=22 nmol phenylalanine/mol tunichrome) is detected in 1 to 10 days; significantly higher amounts of radiolabel (57 Ci/mol tunichrome=318 nmol phenylalanine/mol tunichrome) appear 20 days after seawater exposure. Therefore, phenylalanine can function as a precursor in the biosynthesis of tunichrome.     

The effect of cyclic AMP on dog renal function

Summary The infusion of dibutyryl-cyclic AMP into the dog renal artery in vivo leads to diuresis, natriuresis and glucosuria. Addition of the nucleotide to the incubation medium bathing dog renal cortex slices in vitro causes inhibition of p-amino-hippurate accumulation and stimulation of glycine and -methyl-glucoside transport. The results are interpreted in terms of the development of a blood-lumen flux of sodium and water in the renal proximal tubule, analogous to that seen in the intestine.We are grateful to Mrs P. Ganguillet, S. Henriot, Miss M. Augstburger and D. Mettraux technical skilful technical assistance, and to the Fonds National Suisse for financial support.     

对钢混桥梁面板中压缩薄膜效应的试验研究

为了研究钢混桥梁面板在压缩薄膜效应作用下的结构性能和真实承载能力,进行了一组1∶3比例桥梁模型的静力加载试验;并通过对混凝土强度、配筋率和支撑梁尺寸的改变来分析压缩薄膜效应对结构承载能力的影响。将试验结果与现行规范计算结果和数值模拟结果进行比较后发现,现行的设计方法不能够准确地反映桥梁面板的真实承载能力,而数值分析结果与试验结果有着较好的吻合。     

家用远程智能控制器的设计

给出了利用单片机及TM8880双音多频（DTMF）编、解码电路构成的智能控制系统，这套系统能够通过电话网提供交互式远程控制。     

Assessing the biogenicity and syngenicity of candidate bioalteration textures in pillow lavas of the～2.52 Ga Wutai greenstone terrane of China

Microorganisms that inhabit sub-seafloor lavas are capable of etching volcanic glass and creating micron-sized tunnels and pits. Mineralization of these bioalteration traces ensures that these textures survive deformation and transformation of the host glass to metamorphic minerals. The fossil record of such bioalteration textures extends far beyond volcanic glass from in-situ oceanic crust to include meta-volcanic glass from ophiolites and Precambrian greenstone belts. Investigation of petrographic thin se...     

A ferric-chelate reductase for iron uptake from soils

Iron deficiency afflicts more than three billion people worldwide, and plants are the principal source of iron in most diets. Low availability of iron often limits plant growth because iron forms insoluble ferric oxides, leaving only a small, organically complexed fraction in soil solutions. The enzyme ferric-chelate reductase is required for most plants to acquire soluble iron. Here we report the isolation of the FRO2 gene, which is expressed in iron-deficient roots of Arabidopsis. FRO2 belongs to a superfamily of flavocytochromes that transport electrons across membranes. It possesses intramembranous binding sites for haem and cytoplasmic binding sites for nucleotide cofactors that donate and transfer electrons. We show that FRO2 is allelic to the frd1 mutations that impair the activity of ferric-chelate reductase. There is a nonsense mutation within the first exon of FRO2 in frd1-1 and a missense mutation within FRO2 in frd1-3. Introduction of functional FRO2 complements the frd1-1 phenotype in transgenic plants. The isolation of FRO2 has implications for the generation of crops with improved nutritional quality and increased growth in iron-deficient soils.     

Drug induced skeletal malformations in the rat

Résumé Des malformations squelettiques: dyssymphyses sternales, des anomalies vertébrales, crâniennes et costales ont été observées, chez des rejetons de rates de souche Sprague-Dawley, traitées avec de la thalidomide, du phénobarbital, de la méthaqualone et du glutéthimide pendant toute la période de gestation.     

Fragile X syndrome without CCG amplification has an FMR1 deletion.

We describe a patient with typical clinical features of the fragile X syndrome, but without cytogenetic expression of the fragile X or an amplified CCG trinucleotide repeat fragment. The patient has a previously uncharacterized submicroscopic deletion encompassing the CCG repeat, the entire FMR1 gene and about 2.5 megabases of flanking sequences. This finding confirms that the fragile X phenotype can exist, without amplification of the CCG repeat or cytogenetic expression of the fragile X, and that fragile X syndrome is a genetically homogeneous disorder involving FMR1. We also found random X-inactivation in the mother of the patient who was shown to be a carrier of this deletion.