John P. Zikakis

Advances in Chitin and Chitosan

Interest in chitin and chitosan continues to grow globally fueled in large measure by a surging interest in the newly explored biotechnological and enzyme engineering aspects of these biorenewable resources. Testimony to that interest is the continuation in the face of difficult economic times of the series of International Conferences on Chitin and Chitosan which has resulted in this volume. Further evidence comes from the expansion in national diversity among those who were in attendance. This enhanced interest also led to the formation of the American Chitoscience Society, the sponsoring organization for the conference. The 5th International Conference on Chitin and Chitosan was held October 17-20, 1991 in Princeton, NJ, U.S.A. It follows in the proud sequence which began with the 1st Conference in Cambridge, MA, U.S.A. in 1977, continued in Sapporo, Japan in 1982, then in Ancona, Italy in 1985 and once again in Trondheim, Norway in 1988. In spite of a recessionary world economy, the response to the 5th Conference was gratifying with presentations made over 4 days in 10 oral and 2 poster sessions. This volume contains 76 of those papers.

Correlation of Dairy Food Intake with Human Antibody to Bovine Milk Xanthine Oxidase

Summary Seventy-three out of 94 human subjects were found to have antibodies to BMXO. Individuals with no BMXO titer had the lowest dairy food consumption of the population tested and there appears to be an inverse relationship between increased dairy fat consumption and decrease in IgA and IgM concentrations in titer groups 1-4. When divided into arbitrary groups according to the geometric mean titer, BMXO titers were higher as the milkfat and whole milk consumption increased (Fig. 1). Multiple regression analysis of the data indicated highly significant correlations (P < 0.0001) between milkshake consumption, milk consumption in early life, abnormal lipoprotein patterns, low serum glucose level and the incidence of tonsillectomy at age 10 or later with the presence of antibodies to BMXO. These correlations and the observation that higher milkfat and whole milk consumption resulted in higher BMXO titers suggest the uptake of dietary BMXO from the gut.

CHITINOLYTIC ACTIVITY OF COMMERCIALLY AVAILABLE β-GLUCOSIDASE

A commercially available β-glucosidase (β-D-glueoside glucohydrolase, E. C. 3.2.1.21) preparation was investigated as a possible alternative to a more expensive commercial chitobiase (chitobiose acetylaminodeoxyglucohydrolase, E. C. 3.2.1.29) for use in chitinase assay. The preparation hydrolyzed N,N 1 -diacetylchitobiose at a rate comparable to the chitobiase, but also hydrolyzed chitin substrates. Regenerated chitin was hydrolyzed to a greater extent with the β-glucosidase preparation alone than when soybean chitinase (chitin glycanohydrolase, E. C. 3.2.1.14) was also included in the reaction. Activity decreased with additional amounts of chitinase in the assay, indicating a competition between the two preparations for the substrate. The β-glucosidase itself may hydrolyze regenerated chitin to a certain extent. The β-glucosidase alone also hydrolyzed microcrystalline chitin and crab shell chitin, with release of N-acetylglucosamine, suggesting the presence of a contaminating chitinase in the β-glucosidase preparation. Further study is indicated in order to determine the limitations of the use of β-glucosidase preparations as sources of chitobiase activity in chitinase assay systems.