No abstract

The manifestations of age-related changes in cellular systems often are not readily identifiable, although at the ultrastructural level there are sites in certain organelles that may be indicative of such changes, e.g., the lysosome system, microbodies, mitochondria, plasma membrane, other membrane systems and cytoplasmic vacuoles. In this study, cytochemistry and electron microscopy reveal a number of age-related changes in the unicellular eugienoid alga, Euglena gracilis "Z". The use of modified Gomori technique shows change in latency in Plasma membrane and cytoplasmic vacuolesA final concentration of 0'1 ~ tetra amino-ruthenium hydroxide chlorochloride [ruthenium red (RR) from Dajac Lab.] was added to 2.5 ~ glutaraldehyde fixative buffered with 0'5 u cacodylate, pH 7.2, room temperature. Cells were rinsed in 0.05 M sodium cacodylate, and osmicated either with or without 0.1 ~o RR (Chambers, 1973) for 1-2 h, at room temperature. GROWTH CONDITIONSAxenic cultures of Euglena gracilis Klebs, strain "Z", were grown as described in Part I of this study (Gomez, Harris & Walne, 1974). RESULTSThe general results of this study are summarised in 'l-able I. ULTRASTRUCTURAL CYTOCHEMISTRY LysosomesCells from mid-logarithmic phase exhibit heavy labelling of acid phosphatase in Golgi regions (Fig. 1). In contrast, older cells show little labelling in the