Inulase had received little attention and there were conflicting statements about its availability in animals.Adapted anthrone-sulfuric acid and Nelson-Somogyi reagents were used for identifying fructose concentration in inulin hydrolyzed by insect and aerobic bacteria extracts as a measure of inulase activity.Bacteria isolated from the insect’s gut were grown in nutrient agar and their extracts were used in hydrolyzing inulin. Aerobic bacteria-free insect extracts were obtained by injecting aureomycin into the gut of the cockroaches.There was no significant aureomycin effect on inulase production by the insects. The greatest inulase activity was around the gastric ceaca region. The major inulase requirement of the insects was met by gastric ceaca region production and not by the bacteria. The assertion that inulase may not be found in animal workd (Bernfeld 1962, Doby 1965, Hoar 1966) is unsupported. Periplaneta americana (Linnaeus) and Blaberus giganteus (Linnaeus) have inulase in their gastric caeca regions.Studies of inulase could lead to better understanding of cockroach physiology and their symbionts. If inulase is eventually synthesized in the laboratory a significant amount of inulin energy would become available to man through the use of synthetic inulase.Honors CollegeBall State UniversityMuncie, IN 47306

Doctor of Philosophy / Department of Entomology / Ming-Shun Chen / C. Michael Smith / The Hessian fly, Mayetiola destructor (Say), is a major pest of wheat, and is controlled mainly through deploying fly-resistant wheat cultivars. This study investigated five M. destructor populations collected from Texas, Louisiana, and Oklahoma, where infestation by Hessian fly has been high in recent years. Eight resistance genes including H12, H13, H17, H18, H22, H25, H26, and Hdic, were found to be highly effective against all tested M. destructor populations in this region, conferring resistance to 80% or more of plants containing one of these resistant genes. The frequency of biotypes virulent to resistant genes ranged from 0 to 45%. A logistic regression model was established to predict biotype frequencies based on the correlation between the percentages of susceptible plants obtained in a virulence test. In addition to the virulence test, the log-odds of virulent biotype frequencies were determined by a traditional approach to predict the logistic regression model. Characterization of a bacterial artificial chromosome (BAC) clone identified a gene encoding a protein with sequence similarity to bacterial levanases. Blast searching with the levanase-like protein identified 14 levanase/inulase-like genes or gene fragments. In this study, we determined the expression levels of these genes in different developmental stages and different tissues of 3-d old larvae of M. destructor. Sequence analysis revealed that six genes encode full length proteins, three were truncated at the 5’ end, and five truncated at the 3’ end. Sequences of putative proteins showed approximately 42% similarities to bacterial levanases or inulases, and 36% similarity to fungal levanases or inulases. No sequence similarities were found with any known animal or plant proteins. Comparative analysis of sequences among 14 levanase/inulase-like genes revealed that positions for intron/exon boundaries are conserved among different genes even though the length of each intron and exon varied among different genes. The expression patterns of the levanase/inulase-like genes were different among developmental stages and larval tissues of M. destructor. Interestingly, three genes presented alternative splicing bands in different developmental stages, and two genes exhibited splicing bands in different tissues of 3 d old M. destructor. This study would be useful for future studies of the characterization and function of levanase/inulase-like genes of these enzymes in plant-insect interactions.