CYTOCHEMICAL LOCALIZATION OF GLUTAMATE DEHYDROGENASES DURING CARPOPHORE DEVELOPMENT IN COPRINUS CINEREUS

Abstract

SUMMARYThe NAD-and NADP-linked glutamatc dehydrogenases were detected in frozen sections of carpophore tissues by means of tetrazolium salt. Material at all stages of development was examined. From the earliest stages NAD-glutamate dehydrogenase was uniformly distributed in the basidial cells of the hymenium, and as the carpophore developed an increasing proportion of cells of the subhymenium came to express enzyme activity. The NADP-glutamate dehydrogenase (NADP-GDH) was initially limited to basidial cells in isolated patches of the hymenium. As development proceeded the proportion of basidia exhibiting NADP-GDH activity increased, as did the proportion of subhymenial cells showing this enzyme activity. No NADP-GDH activity' was detectable in sections of stipe tissue.

Comparison of spectrophotometric and electrophoretic measurements of glutamate dehydrogenase activity during mycelial growth and carpophore development in the basidiomycete Coprinus cinereus

“…Both methods of activity measurement reveal the enormous difference in specific activity between cap and stipe tissues of the same carpophore. But more particularly, the electrophoretic measurements clearly corroborate the histochemical observations [5]. The specific activity in the primordial cap measured spectrophotometrically is less than 4% of that found in the caps of mature carpophores.…”

“…It appears to be virtually a linear increase, but the a Specific activities are expressed as described in the footnote to Table 1. 118 time scale is a rather subjective one (although quite closely related to "real" time [7]) and too few samples have yet been examined for this to be stated with confidence. Nevertheless, electrophoretic data show the increase in activity to be rapid, rather than gradual, over the early stages of development; while cytochemical microscopic observations show that this reflects an increase in the number of cells which possess NADP-GDH activity, rather than an activity increase common to all members of the cell population [5].…”

“…These data have been obtained by spectrophotometric analyses of cell-free tissue homogenates. Recent observations using light microscope cytochemistry of frozen sections have shown that adjacent cells may exhibit these same regulatory contrasts, but they have also shown that the cytochemical technique can reveal considerable enzyme activity in young carpophore primordia in which only minimal activity can be detected by spectrophotometric analysis of cell-free homogenates [5]. Since only a minority of cells of the primordial cap show NADP-GDH activity it has been argued that the difference between the techniques is due to an overwhelming dilution of that activity during extraction for spectrophotometry.…”

Cytochemical localisation of NADP-linked glutamate dehydrogenase newly induced in nitrogen-starved mycelia of Coprinus cinereus

“…We have previously used light microscope cytochemistry to locate NADP-linked glutamate dehydrogenase in sections of the fruit body cap [7]. In this paper we report the results of attempts to localise the enzyme in mycelial samples examined by electron microscopy.…”

Co-ordinate control of ammonium-scavenging enzymes in the fruit body cap of Coprinus cinereus avoids inhibition of sporulation by ammonium

“…No significant NADP-GDH activity is found in stipe tissues [1]. The enzyme activity is initially localised in basidia [2] and observation of stained nuclei coupled with determination of NADP-GDH activity in the same tissue has shown that increase in enzyme activity was initiated as karyogamy became evident [3]. Activity of the enzyme glutamine synthetase (GS; EC 3.5.1.2) also increases greatly in the developing cap while remaining at low levels in the stipe.…”