Studies of Euglena gracilis in aging cultures II. Ultrastructure

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

Ultrastructure of Auxin‐induced Tumors of the Coleorhiza‐epiblast of Wheat

“…Further work must determine to what extent each of the ultrastructural changes is related to tumor formation per se versus auxin toxicity. For instance, the myelin figures, observed only in the older tumors in the present study, have often been observed in aging, damaged, or otherwise unhealthy tissue in previous studies (Walne, 1967;Palisano and Walne, 1972;Gomez, Harris, and Walne, 1973). Ames (1972) found no major ultrastructural changes in stem parenchyma cells in genetic tumors of tobacco.…”

Studies ofEuglena gracilisin aging cultures. I. Light microscopy and cytochemistry

“…This time-release process could have been triggered by some catabolic process, brought about by macromolecular breakdown (Klamer & Fennell, 1963;Grusky & Aaronson, 1969), accompanied by coalescence of other lysosomes and other vacuolar systems (Nilsson, 1970;Gomez et al, 1973aGomez et al, , 1973b.…”

“…Like Tetrahymena, this area contains a large number of smooth-membrane-bound vesicles associated with the Golgi complex (Nilsson, 1970;Gomez, Harris & Walne, 1973a, 1973b, whereas in Cryptomonas, it is associated with multivesicular bodies (Lucas, 1970). Acid phosphatase, a type of hydrolytic enzyme, is considered to be one of the biochemical markers of lysosomes.…”

Ultrastructure of Auxin-Induced Tumors of the Coleorhiza-Epiblast of Wheat

“…For instance, the myelin figures, observed only in the older tumors in the present study, have often been observed in aging, damaged, or otherwise unhealthy tissue in previous studies (Walne, 1967;Palisano and Walne, 1972;Gomez, Harris, and Walne, 1973). Ames (1972) found no major ultrastructural changes in stem parenchyma cells in genetic tumors of tobacco.…”