The Isolation of Vacuoles from Candida Utilis

Vacuoles containing S-adenosylmethionine have been isolated from the yeast, Candida utilis, by the osmotic lysis of its spheroplasts and differential centrifugation. Culture in the presence of L-methionine and harvest in the stationary phase contributed to the ease of isolation and stability of the vacuoles. The vacuoles showed retentiveness for the sulfonium compound and responded to the vital-staining reaction with Neutral Red. Ultraviolet micrography indicated the homogeneity of the vacuolar preparation.     

Ethnography of Africa: The Usefulness of the Useless

The complex epistemological and methodological problems of data-quality control or ethnographer bias in anthropological research as they relate to the use of the native languages and/or the use of native-interpreter informants are critically reexamined. Summarizing the 1939–1940 Mead-Lowie debate, the paper suggests, on the basis of a close review of selected classic ethnographies of Africa, various ways by which the quality of comparative cross-cultural data could be meaningfully improved . [methodology of cross-cultural research, epistemological issues in anthropology, use of native languages in fieldwork, ethnography of Africa, history of anthropology]     

A method developed for the study of yeast production withTorulopsis Utilis

Conclusions An account is given of the method adopted in the study of yeast production byTorulopsis utilis.     

医学领域的磁共振成像革命——2003年诺贝尔生理及医学奖主要工作介绍

在磁场中 ,自旋的原子核会吸收频率与其自旋频率相同的电磁波 ,使自身能量增加 ,发生能级跃迁 ,当原子核迁移回原能级时 ,就会把多余的能量以电磁波的形式释放出来 ,称为核磁共振 (NMR) .磁共振成像(MRI)利用这一原理 ,依据所释放的能量在物质内部不同结构环境中不同的衰减 ,通过外加梯度磁场检测所发射出的电磁波 ,即可得知构成这一物体原子核的位置和种类 ,据此可以绘制成物体内部的结构图像 .将这种技术用于人体内部结构的成像 ,就产生出一种革命性的医学诊断工具 .快速变化的梯度磁场的应用 ,大大加快了磁共振成像的速度 ,使该技术在临床诊断、科学研究的应用成为现实 ,极大地推动了医学、神经生理学和认知神经科学的迅速发展     

Presence in the Flesh: The Body in Medicine

Presence in the Flesh: The Body in Medicine. Katharine Young. Cambridge, MA: Harvard University Press, 1997.200 pp.     

Significance of alterations in hepatic antioxidant enzymes. Primacy of glutathione peroxidase.

The relative contributions of catalase and the selenoenzyme glutathione peroxidase (GSH-Px) were elucidated in the rat liver by selectively modulating the activities of these enzymes using dietary selenium (Se) and the catalase inhibitor 3-amino-1,2,4-triazole (3-AT). Increased peroxidation occurred only in Se-deficient rats with markedly reduced cytosolic and mitochondrial GSH-Px activities. Although 3-AT treatment resulted in a 75% reduction of hepatic catalase activity and also a 20% reduction of both cytosolic and mitochondrial superoxide dismutase (SOD) activity, no incremental increase in peroxidation was observed over that associated with Se deficiency. In Se-deficient animals, treatment with 3-AT resulted in a doubling of cytosolic GSH-Px. This was associated with a 49% elevation in hepatic Se suggesting that increased Se may have contributed to the enhanced GSH-Px activity. These results suggest that GSH-Px plays the pivotal role in preventing hepatic peroxidation. Furthermore, the effects of 3-AT in vivo are not restricted to inhibition of catalase activity insofar as it also affects cytosolic GSH-Px activity and cytosolic and mitochondrial SOD activities.