A REINTERPRETATION OF THE ONTOGENY OF THE ASCOCARP OF SPECIES OF THE ERYSIPHACEAE

A study of four species of Erysiphaceae (Uncinula salicis, Podosphaera leucotricha, Erysiphe cichoracearum, and Microsphaera diffusa) revealed that the binucleate stages of the ascocarp are initiated in a similar manner to those of Diporotheca rhizophila Gordon & Shaw. The “appendages” developing on immature ascocarps are considered to be receptive hyphae. Appendages characteristic of mature ascocarps are produced much later. Lysis of certain centrum cells occurs, and asci are initiated from some of the remaining binucleate centrum cells. Resorption of centrum cells by the asci is supported by this investigation, corroborating Björling's earlier studies on Erysiphe graminis.     

EFFECT OF CYCLOHEXIMIDE ON THE CELL CYCLE OF THE CRYPTS OF THE SMALL INTESTINE OF THE RAT

A single injection of 1.5 mg/kg of cycloheximide induces a complete disappearance of mitotic activity in rat intestinal crypts within 1.5–2 hr. No significant necrosis of crypt cells is observed even though this phenomenon is accompanied by a marked decrease in uptake of labeled precursors into protein and DNA. Mitoses reappear 6 hr after injection and recovery then follows a cyclic pattern over a period equivalent to one cell cycle, thereby reflecting at least a partial synchronization of cell division. Concurrent use of colchicine, an agent known to induce metaphase arrest, has demonstrated that cycloheximide, while having no apparent effect on cells already in division, prevents the entrance of new cells into visible mitosis. Analysis of the cell cycle suggests that one block initiated by cycloheximide occurs in G₂, presumably as the result of an interference with the formation of protein(s) required for the normal progression of cells from this phase of the cycle into mitosis.     

哈萨克族儿童发样微量元素测定与比较分析

本文采用原子吸收分光光度法测定了新疆伊犁地区3l例12-15岁哈萨克族儿童头发中的Zn、Fe、Cu、Mn、Ca等5种微量元素的含量;用方差分析法进行了差别显著性检验;并将测定结果与维吾尔族、汉族、柯尔克孜族及回族等4个民族儿童发样做了比较分析;发现除了哈萨克族与柯尔克孜族儿童发样中微量元素Mn、Ca含量有差异外,哈萨克族与维吾尔族、柯尔克孜族儿童发样中微量元素含量无显著性差异。