The effects of UV irradiation (254 mmu) on a coccoid blue-green alga Agmenellum quadruplicatum, Strain PR-6, have been examined in terms of the survival curve and measurement of short time photosynthetic rates. From study of survival evidence has been found for a strong photoreactivation centered near 430 mmu. Measurements of photosynthetic rate suggest that there is a correlation between decay...

The dark synthesis of biliproteins in the blue-green alga Tolypothrix tenuis is controlled by brief light treatments. Green light potentiates synthesis of phycoerythrin and red light potentiates synthesis of phycocyanin. Red reverses the effect of green and vice versa. Action spectra for the red and green effects were obtained for the wavelength region 320 nanometers to 710 nanometers, at 10-na...

A tobacco-like odorous compound isolated from a bloom of the blue-green alga M icrocystis w esenbergii and a laboratory culture of M. aeruginosa was analysed by gas-liquid chromatography and mass spectrometry. Its structure was determined as /?-cyclocitral. No other monoterpenes have been detected in these and in other blue-green algae. The hydrocarbon content was 0.10 — 0.18% of the dry weight...

A toxin extracted from a waterbloom of the blue-green alga Microcystis aeruginosa was found to have an LDioo to mice of 3 mg/kg. Death occurred in less than 4 hours and was accompanied by symptoms corresponding to those of the fast death factor found by others in blue-green algae. The toxin was found to have no effects on three species of fish and a microcrustacean in concentrations up to 10 mg...

The sandy substrate of Lake Taharoa (west coast, North Island, New Zealand 35°50'S, 173°41'E) is covered by communities of filamentous algae that extend from the exposed beach down to 21 m depth. The algae bind the sand to form crusts and mats which may break off as discrete plates. The dominant species are the blue-greens Microcoleus, Nostoc, Phormidium, Lyngbya, Oscillatoria, Scytonema, Stigo...

photosynthetic systems. I t seems as if the blue-green bacteria are a key intermediate in the development of photosynthesis and also in the development of the 2Fe ferredoxins, possibly from ferredoxins containing a 4Fe4S centre. This last point is also interesting in that it has now been shown that the 2Fe-2s centre is formally derivable from the 4Fe4 s centre in analogue compounds that have be...