EUROPEAN JOURNAL OF ENTOMOLOGY

Eur. J. Entomol. 94 (2): 167-176, 1997

Distribution, stability and binding specificity of a hemagglutinin in the corn earworm, Helicoverpa zea (Lepidoptera: Noctuidae)

ADEYEYE O.A., CHENG J.-Q.

N/A

A hemagglutinin (HA) was detected during all developmental stages of the corn earworm Helicoverpa zea. The HA titer was relatively low at the onset of each developmental stage; it increased very rapidly during each stage and declined considerably just before the onset of the next. The highest HA titer of 4,096 was attained during days 3-5 of fifth-instar larvae. In contrast, the lowest titer of 8 was obtained in adult insects. Female pupal and adult H. zea had higher HA titers than their male cohorts. The hemagglutinin agglutinated red blood cells (RBCs) from a broad range of animals. Its binding specificity was unusual in that the hemagglutination was inhibited by sucrose, N-acetylneuraminic acid, lactose, galactose, maltose, galactosamine and N-acetyl-galactosamine in that order of decreasing effect. The midgut fluid of H. zea larvae contained agglutinins with a specificity that suggests that they were exogenously derived from dietary ingredients. Unlike H. zea hemagglutinin, which failed to agglutinate flesh mouse erythrocytes, hemagglutinins found in the diet and midgut fluid caused strong agglutination of mouse erythrocytes. HA titer fluctuated between and within the various life stages. Unlike many insect lectins, H. zea hemagglutinin is relatively stable after being subjected to repeated cycles of freezing and thawing. Although it is rapidly inactivated at >= 40°C, this lectin is relatively stable at 20°C. Since it is inhibited by 5 mM EDTA, it is probable that the binding action

Keywords: Noctuidae, Helicoverpa zea, lectin, hemagglutinin, binding, erythrocytes

Accepted: April 16, 1996; Published: May 15, 1997  Show citation