Studies on the Nutrition of Colorless Euglenoid Flagellates. IV. Astasia longa

1964 ◽  
Vol 37 (2) ◽  
pp. 240-244 ◽  
Author(s):  
Henry W. Schoenborn
Keyword(s):  
Astasia Longa

Control of cell shape by calcium in the euglenophyceae

1981 ◽  
Vol 49 (1) ◽  
pp. 99-117 ◽  
Author(s):  
J.M. Murray
Keyword(s):  
Endoplasmic Reticulum ◽  
Atpase Activity ◽  
Calcium Oxalate ◽  
Cell Shape ◽  
Motor Units ◽  
Astasia Longa ◽  
Oxalate Precipitation ◽  
Entire Cell ◽  
The Individual ◽  
Euglenoid Movement

The euglenoid flagellates are able to change their shape rapidly in response to a variety of stimuli, or sometimes spontaneously. Two extremes of shape can be identified: the “relaxed” form is cylindrical; the contracted form is a somewhat distorted disc. These 2 forms can be interconverted by treatments that alter the Ca2+ concentration of the entire cell. The level of Ca2+ is believed to be normally controlled by a system of calcium-accumulating membranes, identified in Astasia longa by the technique of calcium oxalate precipitation. The system forms a set of parallel tubes of endoplasmic reticulum, one of which lies immediately below each of the ridges of the pellicle. The individual ridges, each with its associated reticulum, microtubules and other elements are suggested to be independent motor units. Local activation of a small number of these units by Ca2+ is made possible by the arrangement of Ca2+ -sequestering reticulum, producing the characteristic squirming euglenoid movement. Uniform activation or suppression of all units produces the 2 extremes of shape. The pellicle of A. longa with its associated microtubules has been purified and shown to contain a Ca2+ -binding site and ATPase activity.

Gravitactic signal transduction elements in astasia longa investigated during parabolic flights

2003 ◽  
Vol 14 (3) ◽  
pp. 17-24 ◽  
Author(s):  
Peter R. Richter ◽  
Martin Schuster ◽  
Michael Lebert ◽  
Donat-P. Häder
Keyword(s):  
Signal Transduction ◽  
Parabolic Flights ◽  
Astasia Longa

scholarly journals Oxygen toxicity in Astasia

1967 ◽  
Vol 105 (2) ◽  
pp. 813-819 ◽  
Author(s):  
Nicole Bégin-Heick ◽  
J. J. Blum
Keyword(s):  
Carbon Dioxide ◽  
Growth Rate ◽  
Cytochrome C ◽  
Atmospheric Pressure ◽  
Oxygen Toxicity ◽  
Mitochondrial Fraction ◽  
Inhibition Of Growth ◽  
Astasia Longa ◽  
Nadh Cytochrome ◽  
Succinate Oxidase

1. Exposure of Astasia longa to oxygen+carbon dioxide (95:5) at atmospheric pressure leads to an inhibition of growth rate and of respiration. Growth resumes at the normal rate as soon as the oxygenation is discontinued, but respiration recovers more slowly. 2. Mitochondria prepared from cells exposed to oxygen+carbon dioxide (95:5) during growth have considerably decreased activities of succinate–cytochrome c oxidoreductase, NADH–cytochrome c oxidoreductase, succinate dehydrogenase and succinate oxidase activities as compared with mitochondria obtained from cells exposed to air+carbon dioxide (95:5). Cytochrome oxidase activity is not appreciably inhibited by exposure of the cells to 95% oxygen. 3. The mitochondrial fraction of Astasia contains rhodoquinone. The rhodoquinone concentration increases in cells exposed to 95% oxygen. The content of ergosterol-containing compounds also increases in the mitochondria of cells exposed to 95% oxygen. There is little change in the ubiquinone content of the mitochondrial fraction. The ubiquinone of Astasia appears to be ubiquinone-45.

Photoresponse of a colorless Euglenoid flagellate, Astasia longa

1983 ◽  
Vol 32 (1-2) ◽  
pp. 101-107 ◽  
Author(s):  
T. Suzaki ◽  
R.E. Williamson
Keyword(s):  
Astasia Longa

Effects of growth rate on the DNA content of Astasia longa cells

1969 ◽  
Vol 58 (1) ◽  
pp. 55-61 ◽  
Author(s):  
H. Morimoto ◽  
T.W. James
Keyword(s):  
Growth Rate ◽  
Dna Content ◽  
Astasia Longa
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