THE DISTRIBUTION OF THE WATER-SOLUBLE INORGANIC ORTHOPHOSPHATE IONS WITHIN THE CELL: ACCUMULATION IN THE NUCLEUS : Electron Probe Microanalysis

摘要: Lead acetate treatment of unfixed cells immobilizes the intracellular water-soluble, inorganic orthophosphate ions as microcrystalline lead hydroxyapatite precipitates (see reference 1). These have been analyzed with electron microprobe. A much higher concentration phosphorus has found in nucleoli maize root tip fixed acetate-glutaraldehyde (organic plus orthophosphate), compared to roots glutaraldehyde alone phosphorus). The pool these is three five times high macromolecular organic phosphate. Since nearly all latter RNA, phosphate nucleolus calculated be roughly 0.5-0.8 M. About 30%-and up 50%-of total cellular accumulated since mean per cell about 10(-2)M. In extranucleolar part nucleus was estimated by densitometry six less than ( 0.1 M), and appears more concentrated nucleoplasm condensed chromatin. While there no direct evidence for cytoplasm, it certainly must lower level (i.e., < 10(-2)M) 10% volume. implications this compartmentation intact are discussed connection (A) availability cytoplasm those processes which affect rate enzymatic reactions, (B) protein nucleic acid interactions within nucleolus.