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Journal of Experimental Biology 8,319-329 (1931)
Published by Company of Biologists 1931

The Relations Between Yolk and White in the Hen'S Egg : IV. The Formation of Lactic Acid and Alcohol by the Yolk

JOSEPH NEEDHAM ¹, MARJORY STEPHENSON ¹, and DOROTHY MOYLE NEEDHAM ¹

¹ Biochemical Laboratory, Cambridge

1. The vitelline membrane of the infertile hen's egg exhibits no dehydrase activity.

2. The vitelline membrane has no measurable aerobic respiration in vitro, nor has the yolk of the infertile egg. This confirms the view that the carbon dioxide production of the intact egg is not the result of any true respiration.

3. When incubated anaerobically in vitro, bacteriologically sterile yolk produces consistently small amounts of lactic acid.

4. This glycolysis is not the result of any catalytic activity of the vitelline membrane, but takes place throughout the substance of the yolk.

5. Under similar conditions, bacteriologically sterile yolk produces small amounts of a substance or substances estimatable as ethyl alcohol.

6. If the yolk suspension is bacterially contaminated, however, lactic acid and alcohol are produced in amounts closely similar to those found by earlier workers on this subject.

7. The heat of glycolysis, under anaerobic conditions, calculated from the amounts of lactic acid experimentally found to be formed, is of the same order as (a) the calculated requirement of the vitelline membrane (Straub), and (b) the observed heat production (Langworthy and Barott). Thus even if the vitelline membrane is capable of using energy to do osmotic work, the yolk is only capable of supplying it by means of its glycolytic mechanism if the whole energy output of the whole yolk can be made available for doing work at the membrane.