A defense mechanism in the cuticle of developing C. capitata was demonstrated using an in vitro system consisting of isolated cuticular tyrosinase from C. capitata, cuticular tyrosinase-free proteins, tyrosine, and E. coli. The simultaneous presence of the above components resulted in the formation of large immobilized E. coli aggregates. By contrast, omission of any of the above components failed to produce such aggregates. In other words, E. coli retained their mobility and viability. The results indicate that certain cuticular proteins are responsible for the nonself-recognition, since they are able to bind to the E. coli surface in vitro, and a reactive tyrosine derivative is generated by the action of cuticular tyrosinase for the immobilization and probably killing of E. coli. Based on these studies the most likely explanation for the nonself-recognition and immobilization and/or killing of bacteria is the production of E. coli-protein complexes and their crosslinking through quinone intermediate.

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Larval Ceratitrs capitata phenoloxidases (POs) from hemocytes, serum, integument, and fat body were analyzed. Two types of PO were recorded: the tyrosinase type found in hemocytes, serum, integument, and fat body and the laccase type found in integument. Tyrosinase from all larval tissues and integumental laccase as well, showed similarity in molecular weight (93 KDa), activation by Ocherichia coli at 5 m M Ca2+, and reactivity to antibodies raised against serum tyrosinase. However, the enzymes differed with respect to their glycosylation and adhesiveness. The serum and integumental enzyme forms contain concanavalin A reacting material, whereas hemocyte and integumental tyrosrnase(s) are adhesive. These differences in enzyme forms, although not influencing their substrate specificity, seem to give advantages to performing their function, i.e., the adhesive enzyme form facilitates the adherence to f. colicell wall and hemocyte surface (unpublished data) while the glycosylated form facilitated the secretion into serum. o

Hemoglobinopathies represent the most common genetic disorder worldwide, with a higher prevalence among populations with a history of malaria endemicity. More than 690 mutations in the human b-globin gene are usually the cause of b-type hemoglobinopathies. Here, we report a rapid and highly sensitive b-globin gene mutation screening approach based on denaturing high-performance liquid chromatography (DHPLC), which contrary to the previously described ones can be used in every HPLC apparatus. The sensitivity and specificity of the method were tested in 120 healthy Greek subjects and 25 b-thalassemia heterozygotes and homozygotes, in which 11 different b-globin sequence variations had been previously characterized by denaturing gradient gel electrophoresis. Using this method, we were able to rapidly identify the commonest b-globin gene mutations, accounting for more than 90% of the mutant b-globin alleles reported for the Hellenic population. Compared to classical mutation screening approaches, our DHPLC approach provides the means for rapid, highly sensitive, cost-effective, and semi-automated simultaneous mutational scanning of a large number of samples. Am. J. Hematol. 82:168-170, 2007. V V C 2006 Wiley-Liss, Inc.

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