Photosynthetic Properties of Permaplasts of Anacystis

Abstract

A treatment procedure using lysozyme and ethylenediaminetetracetic acid gave intact but permeable cells (permeaplasts) of Anacystis nidulans. Rates of electron transport from water to carbon dioxide, ferricyanide, 2, 6-dichlorophenol indo. phenol, benzoquinone, and methyl viologen, and from reduced indophenol to methyl viologen were measured as a function of treatment time. Rates of oxygen evolution in complete photosynthesis and electron flow from water to methyl viologen showed rapid and parallel decline with treatment time. Electron flow from water to ferricyanide and from reduced indophenol to methyl viologen increased during the first half hour of treatment (phase 1) to 60 to 80% of the original photosynthetic rate. Longer treatment (phase 2) resulted in decreased rate of ferricyanide reduction but not in rate of methyl viologen reduction from indophenol. Electron flow from water to quinone was two to three times higher than for complete photosynthesis in intact cells. It remained high during phase 1 and declined during phase 2. Phase 1 permeaplasts apparently retain high activity for photosystems 1 and 2 photoreactions. This alga is less sensitive to lysozyme than others examined and is easily manipulated. Cultures were grown in medium C (7), modified by doubled concentrations of iron and microelements, in a continuous culture chamber (11) at 30 C, and aerated with 1% CO, in air. At 100 ft-c from tungsten lamps and a cell concentration of 2.5 [l cells/ml, the specific growth rate was about 0.9/day.A standard permeaplast preparation was obtained by the following procedure. A harvested cell suspension was centrifuged at 12,000g for 5 to 10 min at 0 C, and the cells were resuspended in 50 mm TES buffer at pH 7.3 to give 7 to 10 1d cells/ml. Lysozyme (Worthington Biochemicals, 2X recrystallized) was added to give 1.5 to 2.0 mg/lA cells, and Na4EDTA was added to give 1.0 mm. Cell suspensions were incubated in 15-ml tubes, about 5 ml/tube at 35 C in room light with occasional stirring by a Vortex mixer. After desired time of treatment, aliquots of suspension were diluted in several volumes of cold TES buffer, centrifuged for 5 to 10 min at 12,000g at 0 C, washed in TES buffer, and resuspended in room temperature TES to give cell concentrations of 0.5 to 2.0 /il/ml for assay. Most preparations gave relatively stable activities for about 1 hr when maintained at room temperature after the initial centrifugation.Oxygen exchange was measured by a Beckman oxygen macroelectrode in a cuvette of about 1.5 ml (12) or by a YSI 5331 electrode in a 1.6-ml cuvette at 25 C (17

Differential action of Hg2+ and Cd2+ on the phycobilisomes and chlorophyll a fluorescence, and photosystem II dependent electron transport in the cyanobacterium Anabaena flos-aquae

“…Permeaplasts were prepared as described by Wards & Myers (1972). The exponentially growing cultures were harvested by centrifugation (400 x g, 10 min) and were washed twice with the glass distilled water.…”

Transformation of the cyanobacterium Anacystis nidulans 6301 with the Escherichia coli plasmid pBR322.

“…4 (27). In the present study, we have used permeaplasts (19), which are highly permeable cells that have a high efficiency of cell-wall regeneration and subsequent division, to study DNA uptake and genetic transformation. The more than 50-fold higher transformation efficiency observed for permeaplasts as compared to cells reflects an enormous increase in DNA uptake.…”

The non-light-dependent reduction of 2,6-dichlorophenolindophenol by cells of the blue-green alga Anacystis nidulans

“…Although intact that exhibited by Anacystis. cells of algae do not generally photoreduce This communication compares character-DPIP, membrane preparations (2, 4) and istics of the endogenous dark reduction of lysozyme-treated whole cells (9) have exhibited DPIP by cells of Anacystis nidlrlans with that photoreductive capabilities. During earlier observed in other blue-green algae and destudies on photosynthetic electron transport in scribes several salient features of the Anacystis Anacystis (8,9), a non-light-dependent re-dark reduction phenomenon.…”

“…Permeaplasts of Anacystis nidulans were prepared according to the method of Ward and Myers (9). The use of TES (N-tris(hydroxymethy1)methyl-2-amino-ethane sulfonic acid) buffer instead of phosphate was necessary for successful treatment.…”