Date of Award

12-1-1980

Degree Type

Dissertation

University or Center

Atlanta University (AU)

Degree Name

Ph.D.

Department

Biology

First Advisor

John M. Browne

Abstract

Hyaluronidase and hyaluronic acid have been shown to play an important role in regulating embryogenesis in several animals. Experimental evidence indicates that hyaluronic acid regulates embryonic morphogenesis by preventing untimely cellular interactions and, hence, permits the appropriate accumulation of cells. It is degraded by hyaluronidase at an appropriate time during embryogenesis to allow cellular interaction leading to coordinate differentiation.

Currently research is directed towards understanding the mechanism of action of hyaluronidase on hyaluronic acid and the structure and moiety relationship of these two important compounds. These studies have included charac terization of hyaluronidase from different sources, and have resulted in the discovery of several forms of hyaluronidase. In the chick, two forms of this enzyme are present: cellular and secretory, with different kinetic properties. These differences are thought to be attributable to structural modifications. It is not known whether these modifications are co- or post-transitional.

In the work reported here, hyaluronidase has been isolated from chick brain fluid and its characteristics studied in relation to chick brain morphogenesis. It is apparently a secretory form with pH optimum at 3.5 to 4.5, but also has activity at neutral pH. Its activity is modulated by cations. Evidence is also presented which suggests a strong association, possibly a complex, between chick brain fluid hyaluronic acid and hyaluronidase activitycontaining protein(s). This association seems to have a regulatory role on interactions between hyaluronic acid and hyaluronidase during brain morphogenesis.

The molecular weight of the chick brain fluid hyaluroni dase was estimated by SDS pollyacrylamide gel electrophoresis at approximately 70,000 daltons.

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