OF EXPERIMENTAL WORK I97 



OXYGEN CONSUMPTION 



See Respiration 



OXYGEN-LACK (aNAEROBIOSIS) AND LOW OXYGEN TENSION 



Size 0/ Egg. — Slightly smaller in absence of oxygen (Hunter, 1936), but not statistic- 

 ally significant (Keckwick and E. N. Harvey, 1934). 



Life-Span. — Of unfertilized egg increased, slightly, much less than with KCN (Loeb 

 and Lewis, 1902; Loeb, 191 1, 1913a, p. 26). 



Unfertilized Egg. — Remains normal for 8 hours in absence of oxygen, with slight 

 delay in formation of fertilization membrane and cleavage when fertilized (in air) 

 after 3 or more hours without oxygen (E. B. Harvey, 1930); normal for 5 hours 

 (Barron, 1932). 



Fertilization Membrane. — No fertilization membrane formed if fertilized in absence 

 of oxygen, but sperm are not motile (E. B. Harvey, 1930; see Barron, 1932). Fertil- 

 ization membrane is formed on parthenogenetic eggs in absence of oxygen (Kitching 

 and Moser, 1940). 



Cleavage Arrested. — Reversibly (Loeb, 1895, translated 1905; 1913a, p. 25; Lyon, 

 1902, susceptible period 10-12 minutes after fertilization; E. B. Harvey, 1927, for 

 P. lividus and Ps. microtuberculatus, susceptible period just before cleavage; E. B. 

 Harvey, 1930, for A. punctulata; Amberson, 1928; Tang and Gerard, 1932; Runn- 

 strom, 1935 a, even with pyocyanine; Clowes and Krahl, 1940). 



Low Oxygen Tension. — On respiration and cleavage. Oxygen consumption practic- 

 ally constant between 228 and 20 mm. Hg, reduced below 20 mm. Hg. Cleavage 

 not retarded until below 1 1 mm. Hg, and arrested below 4 mm. Hg (Amberson, 

 1 928) . Similar results by Tang and Gerard (1932); Kitching and Moser 1 940 ; Clowes 

 and Krahl (1940). 



Reversed by ATP (Barnett, 1953). 



On respiration of unfertilized eggs. Oxygen consumption begins to fall at 20 mm. 

 Hg (Tang 1931a). 



Asters. — Not formed, or disappear in absence of oxygen; reversible (Mathews, 

 1907; E. B. Harvey, 1921, 1930). 



Cleavage Planes. — Obliterated by oxygen-lack, but on admitting air, irregular 

 cleavage planes come in and go (Loeb, 1905, p. 401 ; E. B. Harvey, 1927, 1930) and 

 result in normal blastulae and plutei. Similar results with urethane and ether (see 

 Anaesthetics), and high hydrostatic Pressures, q.v.). 



Embryos. — Disintegrate in lack of oxygen (Lyon, 1902). 



X-Rayed Eggs. — Have less cleavage delay in absence of oxygen (Anderson, 1939) 



Toxicity. — Of salts, etc. reduced (Loeb, 1910). 



Amoeboid Motion Produced by Urea. — Is arrested ; also arrested by high hydrostatic 

 pressures (Kitching and Moser, 1940). 



Echinochrome . — Is released from unfertilized eggs in O2 lack (Shapiro, 1946). 

 Echinochrome not changed to the reduced form by O2 lack. See under Echino- 

 chrome. 



Permeability. — To water and ethylene glycol not affected by oxygen-lack (Hunter 

 and E. N. Harvey, 1936; Hunter, 1936, correcting Keckwick and E. N. Harvey, 

 1934, Hunter and E. N. Harvey, 1935). 



Parthenogenesis. — Caused by oxygen-lack (Mathews, 1900; McClendon, 1909b, 

 1910b). 



Sperm. — Immobilized by absence of oxygen, reversible till after 3 to 4 hours expo- 

 sure. Fertilizing power lost and no recovery after 4 hours (E. B. Harvey, 1930; see 

 also Barron, 1932). Motility and fertilizing capacity maintained by glycine and 

 other amino acids (Tyler and Lord Rothschild, 1951; Tyler, 1953). 



