BIOCHEMICAL STUDIES ON THE COELOMIC FLUID OF NEPHTYS HOMBERGI (POLYCHAETA: NEPHTYIDAE), WITH OBSERVATIONS ON CHANGES DURING DIFFERENT PHYSIOLOGICAL STATES

¹ Department of Zoology, University of Bristol, Bristol, England

1. The coelomic fluid of Nephtys hombergi was examined with respect to its pH, buffering capacity, and carbohydrate and nitrogen distributions.

2. The pH of normal worms lies between 6.4 and 6.6, and the buffering capacity is 8 meq/l./pH unit between pH 4.5 and 7.5.

3. The carbohydrates are distributed between a small alcohol-insoluble fraction (not glycogen) and an alcohol-soluble fraction, shown by chromatography to consist of 50-70 mg./100 ml., each, of glucose and maltose.

4. The alcohol-insoluble nitrogenous compounds range from 70-150 mg./100 ml. Only about half is due to -amino groups from protein and the rest is unidentified.

5. The alcohol-insoluble nitrogen lies between 180-260 mg./100 ml. Of this, about 90 mg. are due to -amino nitrogen and ammonia, about 10 mg. to peptides, and the remainder is unknown. Quantitative amino acid chromatography gave total amino acid levels at between 40-60 mg./100 ml., about half of which is glycine. Alanine and proline are also prominent.

6. Starvation for 10 days has no consistent effect on nitrogen distribution, but it causes a fall in free sugars and an increase in alcohol-precipitable carbohydrates, except in breeding worms.

7. Breeding worms are able to maintain a high level of free sugars despite starvation and also show an increase in the unidentified alcohol-soluble nitrogenous fraction. A similar picture is brought about in non-breeding worms by extirpation of the supraoesophageal ganglion, an operation which also induces precocious maturation.

8. Caudal amputation of segments has little effect on coelomic fluid chemistry except temporarily to raise the pH by 0.2 to 0.3 unit around the third day of regeneration. This may be the result of exposure of the coelom to sea water.