Gamete formation reflects the sexual pheromone hierarchy ofDictyostelium giganteum

Summary Sexual development inDictyostelium giganteum begins with the appearance of small, amoeboid gametes that fuse to produce mainly binucleate cells which differentiate into zygote giant cells. The data presented here show that the number of gametes produced by each strain (WS589>WS606>WS607>WS588) is directly related to its position in this hierarchy.This work was supported by a grant (A6807) from the Natural Sciences and Engineering Research Council of Canada.     

‘Waldsterben’, part IV (continuing series)

Summary Peroxidase and superoxide dismutase activities, and ascorbic acid content, were measured in both intercellular fluid and cell material of current and 1-year-old needles of Norway spruce saplings treated with ozone, ambient air and activated carbon-filtered air in outdoor fumigation chambers. Ethylene evolution was also compared. Plants from carbon-filtered air treatments had significantly lower enzyme activities and higher ascorbic acid content. These changes were more marked in intercellular fluid than in cell material. Significant changes were noted at ozone levels typical of ambient air quality in a typical urban area. These results suggest the need for simultaneous screening of several biochemical markers as a way of overcoming the lack of specificity of any single marker for the identification of a perturbation by a particular stress, such as ozone.Acknowledgments. This work was supported in part by Grant Number 4849-0.85 (NFP 14) from the Swiss National Fund of Scientific Research. We thank Dr. F. Cupelin and Dr. J. Cl. Landry from the Service d'Ecotoxicologie, Genève, who provided the facilities for the monitoring of ozone levels. We also thank A. Mesrobian, A. Rossier and D. Voluntaru for technical assistance. Du Pont de Nemours International is gratefully acknowledged for the gift of TEDLAR (polyvinyl fluoride film) to build up the fumigation chambers.     

Extractive components from the nutmeg ofMyristica simarum A. DC.: The structure of lignan-ketone: Otobanone

Summary Otobanon obtained fromn-hexane extract ofMyristica simarum A. DC. was elucidated as 1-oxo-otobain by the physical spectra and chemical degradation.Acknowledgment. The authors are indebted to Chemical Research Center for financial support under the project No. CRC-6203, which supported by the National Council on Science Development of China.     

微处理机的功能测试

微处理机的功能测试无论对微处理机的设计、生产和使用都是非常重要的.本文是Thatteand Abraham给出方法的扩展和补充.本文的测试方法能诊察某些文献^[1]给出的方法不能诊察的故障,利用一个测试,检查几种类型的功能故障,而使测试简化.     

cis-cylohexane-1,2-diol in the beaver gland

Zusammenfassung Aus den Biberdrüsen wurdecis-Cyclohexan-1,2-diol isoliert und charakterisiert.

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The support of this work by the Colombo Plan administration of Canada is gratefully acknowledged.     

Impaired amylase release from the parotid gland of rats treated with reserpine

Summary Using an automated system for the analysis of amylase, the release of this enzyme was compared in superfused parotid gland segments from control and reserpine treated rats. Stimulant-evoked amylase release was delayed and of smaller magnitude in the glands of the treated animals and a reduction of the transmembrane K⁺ gradient caused a smaller and short lasting reduction in Ach-evoked release of amylase in the glands from these animals.This work was supported by grants from the Cystic Fibrosis Research Trust (U.K.), Cystic Fibrosis Foundation (USA) and University of Missouri.