Effect of Aminotriazole and Streptomycin on Multiplication and Pigment Production of Photosynthetic Microorganisms*

SYNOPSIS. Normal Euglena gracilis, strain z, growing in the light in defined medium (initial nitrogen concentration 140 μ/ml) depletes the medium of all ninhydrin‐positive N by the time a cell density of 2 million per ml is reached. A further 2‐ to 3‐fold increase in the cell number takes place in the absence of exogenous N. The N content of an early log phase cell is about 100 picograms but decreases very rapidly as the culture continues to grow, reaching 22 picograms in the stationary phase. When grown in the dark, normal cells take up N somewhat more slowly but the supernatant fluid from saturation cultures is again devoid of N. At modest cell densities, the permanently bleached strains examined contain less N per cell than do normal strains. The cultures of the bleached strains achieve a maximum density of about 1 to 2 million per ml rather than the 4 to 5 million reached by the normal strain. As a result, supernates from stationary phase cultures of bleached cells still contain a large proportion of the total N supplied. Paper chromatographic analysis of these supernates reveals several ninhydrin‐positive compounds. Most of these have been identified as common amino acids. Some of the properties of two unidentified, ninhydrin‐positive compounds are described.

Section: Lack Of Evidence For Encystment In the Parasitic Amoebamentioning

confidence: 87%

Accumulation of Extracellular Amino Acids by Euglena gracilis

McCalla

1963

“…Of particular interest have been the observations on the relative ease with which chlorophyll can be made to disappear permanently from some strains of euglena. Agents such as streptomycin ( 1,4,17,19), heat (3,14) and ultraviolet light (6,12) have been shown to bring about irreversible changes leading to "bleached" cells. In addition it has been observed ( 10,18,20) that spontaneously many of the cells can give rise to "variants," e.g., pale green, yellowish or whitish clones many of which are irreversibly changed.…”

Section: The Plastid System Of Normal and Bleached Euglena Gracizip Amentioning

confidence: 99%

The Plastid System of Normal and Bleached *Euglena gracilis**

Gibor¹,

Granick²

1962

SYNOPSIS. The plastid system of “normal”Euglena gracilis strain Z was found to be extremely unstable. Under normal culture conditions in the light about 1 or 2% of the cells were found to have lost spontaneously the capacity to green on further culturing. Cells treated with streptomycin, heat or U.V. all lost the capacity to green on further culturing. Bleached cells whether appearing spontaneously or by induction with streptomycin, heat, or U.V. light, were all found to possess within them organelles which were identified as proplastids. The proplastids of some “bleached” strains were capable of synthesizing porphyrins when grown in a standard culture medium. Others synthesized porphyrins only after the addition of delta‐aminolevulinic acid to their medium, while proplastids of still other strains could not synthesize porphyrins from this precursor. Normal cells when grown in total darkness were found to possess proplastids morphologically identical with those of the bleached strains. Upon exposure to light the proplastids enlarged and greened. In cells which grew under continuous light the plastid system appeared as an interconnected system of tubules. Cells maintained on a schedule of 12‐hour light and 12‐hour dark had plastids which were detached from each other.

“…Effect of AT on multiplication and pigment synthesis. AT inhibited the multiplication of several photosynthetic organisms equally in the light or in the dark (1). AT also bleached light-grown cells; this bleaching was not permanent ( 1 ) .…”

Section: Resultsmentioning

confidence: 97%

Mode of Action of 3‐Amino‐l,2,4‐Triazole on Photosynthetic Microorganisms*

Aaronson

1960

Self Cite

SYNOPSIS. 3‐Amino‐l,2,4‐triazole (AT) inhibits the multiplication and pigment synthesis of several photosynthetic pro‐tists, Ochromonas danica, 0. malhamensis, Euglena gracilis and Rhodopseudomonas palustris; it also inhibits the catalase activity of beef liver and O. malhamensis. Fe++, Fe+++ or lecithin annul the inhibition by AT of multiplication and pigment synthesis in O. danica. Chelation of iron is suggested as the main action of AT on Odanica,