AN EXPERIMENTAL STUDY OF PROTOPLASMIC pH DETERMINATION 1. AMOEBAE AND ARBACIA PUNCTULATA

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Abstract
The microinjection of pH indicators into the living cell presents numerous difficulties such as the salt and protein errors of the indicators, membrane formation, granular breakdown, and the uptake of indicators by the granules. To avoid factors due to the presence of granules indicators were injected into the hyaline region of centri-fuged Arbacia punctulata eggs, Amoeba proteus and A. dubia. Sulfonephthalein indicators and certain mixed indicators were used. A mixed indicator has the advantage of a sharp color transformation point at a given pH. Varied results were obtained with the indicators under different conditions of experimentation. The results indicate a pH of 6.8 [plus or minus] 0.2 for the hyaline protoplasm of A. proteus and A. dubia. For the hyaline protoplasm of the Arbacia punctulata egg the pH is about 6.2 [plus or minus] 0.2. Protein-lipid errors of indicators detd. with Arbacia substance vary from pH [long dash] 0.17 to [plus or minus]0.9 for various indicators.