Photosynthetic properties of extracts of Anacystis nidulans prepared by lysozyme digestion

Abstract

Cell-free extracts of A. nidulans show high rates of cyclic and noncyclic photophosphorylation and P/2e ratios of about 0.8. These extracts also reduced ferricyanide at rates as high as 700 μmol/mg chlorophyll per hour. Rates of dichlorophenol indophenol (DCPIP) reduction and reduced cytochrome c oxidation similar to those previously reported in the literature have also been observed. The extracts, however, showed no NADP-reducing capacity. Subjecting cell-free extracts to cold shock caused no decline in electron flow but a marked decline in photophosphorylation. The sensitivity of photosynthesis of this organism to cold shock (1, 2) might be explained, at least to some extent, by this decline in photophosphorylation.

Spectral Changes in Anacystis nidulans Induced by Chilling

“…These results appear to reflect differences in membranes of cells grown at 39 and 25 C. The work described in this and in the previous paper extends previous observations which demonstrated cold sensitivity in Anacystis (2,5,6) and a change in the physical state of Anacystis membranes as they are chilled (10).…”

The effect of Ca2+ on oxygen evolution in membrane preparations from Anacystis nidulans

“…Highly active preparations usually require incubation of cells with lysozyme under carefully controlled conditions, followed by separation of the membrane fraction from soluble components [4,5]. These preparations are often lengthy, and in our hands lead to variable activities from one preparation to the next.…”

Immobilization of photosynthetically active cyanobacteria in glutaraldehyde-crosslinked albumin matrix

“…It is known, however, that low temperatures adversely affect fundamental cyanobacterial functions, such as the electronic excitation coupling of phycobiliproteins to Chl a (Schreiber 1979), the photosynthetic electron transport (Jansz and Maclean 1972;Rao et al 1977) and the photophosphorylation (Jansz and Maclean 1972a). To minimize such cryotoxic effects, we attempt first to entrap Anacystis by means of prolonged incubation in the albumin-glutaraldehyde mixture at 0°C, but without the deep freeze-thaw cycle.…”