Glycogen Content of Fresh-Water Mussels

Abstract

Determinations of the glycogen content of fresh-water mussels have been made, using a modification of the Pflüger method as described by Cori. 1 Separate determinations were made on the hepato-pancreas and foot muscle. The results are expressed in percentages of the wet and dry weights of the tissues analyzed.

Fourteen different species of fresh-water mussels were used in the work. Altogether, 51 mussels were analyzed. Many of them had been in the laboratory for some time. They were kept in tanks containing sand and a steady, slow stream of tap water was allowed to flow over them. No food was given them. Others were brought in for analysis from various sources.

A number of the results are interesting. As might be expected, the mussels kept in the laboratory without food showed a gradual decrease in the glycogen content. This seemed to be more pronounced in the hepato-pancreas than in the foot. In Fusconaia undata, for instance, the glycogen content (based on wet weight) of the hepato-pancreas dropped from 7.15% on February 14 to 1.24% on April 14, a loss of 82.7%. At the same time the foot content changed from 2.2% to 0.735%, a loss of only 66.6%. Frequently, in fact, in the starved animals, the percentage glycogen content of the foot was found to be slightly higher than that of the hepato-pancreas, while normally in well fed animals the reverse was true, the hepato-pancreas being 2 or 3 times as rich in glycogen as the foot muscle.

In many instances after long continued fasting the mussel contained too little glycogen to be determined accurately.