Cloning and expression in E. coli of the malarial sporozoite surface antigen gene from Plasmodium knowlesi

The malarial sporozoite, the infective stage found in the salivary gland of the insect vector, bears highly immunogenic surface antigen(s). Repeated exposure to irradiated sporozoites induces protection against malaria in several host species, including man. Further, monoclonal antibodies that confer passive immunity react with the immunogenic surface determinants of different sporozoite species. One approach to prevent malaria, therefore, would be to produce a vaccine that induces high titres of circulating antibodies against the sporozoite surface determinant(s). However, production of such a vaccine has not been possible since sporozoites cannot be cultivated in vitro and, therefore, only limited amounts of surface antigen may be obtained. To overcome this problem, we have prepared mRNA from Plasmodium knowlesi-infected mosquitoes to construct a cDNA library. From this library we have isolated a clone that expresses the sporozoite surface antigen as a beta-lactamase fusion protein in the plasmid pBR322. This is the first potentially protective malarial antigen to be cloned by recombinant DNA technology.     

A new model of glucocorticoid-induced metanephric maldevelopment

A new experimental model of glucocorticoid-induced tubular cyst formation has been developed in metanephric organ culture. The addition of cortisol (1.4 X 10(-5) M) to chemically defined serum-free culture medium produces cystic changes during in vitro nephrogenesis . The model isolates the role of glucocorticoids in experimental cyst formation.     

Inhibition of rat testicular monoamine oxidase activity after 250 R of whole-body X-irradiation

Résumé Chez le rat l'activité de l'oxydase testiculaire monoaminée est augmentée d'une manière significative 7 à 10 jours après une irradiation-X de 250 R du corps entier. Elle s'est abaissée au-dessous de la valeur du contrôle pendant les 153 jours qui suivirent le traitement.

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This research was sponsored by Utah State University Research Project U-300, and U.S. Atomic Energy Commission Grant No. AT(11-1)-1602.     

A diploid population ofPoa annua L. from Australia

Résumé On décrit une population diploide dePoa annua L. d'Australie. Elle se montre différente des «mphihaploides» qui ont été trouvées en Californie. La signification de cette population en rapport avec l'origine supposée deP. annua est considerée.

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Acknowledgement. This work was supported by a grant from the Nuffield Foundation.     

半胱氨酸亚金铵的合成、理化性质及电镀金应用

以半胱氨酸为配体合成一种新型亚金配合物NH4Au(Cys)2,对该配合物进行元素分析、红外光谱、紫外光谱、热失重分析和导电性测量等理化性质研究;以该亚金配合物为金源开展相关的电镀金工艺探索,并通过四因素三水平的正交试验获得其最佳条件参数;采用扫描电子显微镜(SEM)和X线衍射(XRD)对镀金层的表面质量进行探讨。研究结果表明:该目标产物的分子式为NH4Au(Cys)2·2H2O,该配合物中以半胱氨酸的巯基和金配位为成健特征,在170℃以下热稳定性较好,该亚金配合物是一个典型的离子化合物。在电流密度为200~300 A/m2,p H为10.5~12.0,温度为35~45℃,金质量浓度为15~25 g/L的电镀工艺条件下,得到粒度为0.5~1.0μm的单质金,且主要沿着(111)面进行生长。