RESUMEN
In the subterranean termite Reticulitermes flavipes, allatostatins (ASTs) with the C-terminus Phe-Gly Leu-amide were localized by immunocytochemistry with antibody against a cockroach AST, Dippu AST-7. AST-immunoreactivity occurred in the corpus cardiacum and corpus allatum and in the lateral and medial neurosecretory cells of the brain that innervate these organs as well as in many other nerve cells of the brain. This was observed in workers, nymphs, soldiers and secondary reproductives. A radioimmunoassay, using anti-Dippu AST-11, demonstrated about 40 fmole equivalents of AST in brains of soldiers and secondary reproductives. The product of the corpora allata in this species was determined to be juvenile hormone III. Its synthesis by corpora allata of secondary reproductives, determined by in vitro radiochemical assay, was inhibited in a dose-dependent fashion by two cockroach allatostatins, Dippu AST-7 and Dippu AST-11. Thus, as in cockroaches and crickets, allatostatin-containing nerves innervate the corpora allata of this termite species and their production of juvenile hormone is inhibited by these neuropeptides.
Asunto(s)
Corpora Allata/metabolismo , Isópteros/metabolismo , Neuropéptidos/fisiología , Animales , Encéfalo/metabolismo , Encéfalo/ultraestructura , Corpora Allata/ultraestructura , Inmunohistoquímica , Hormonas Juveniles/biosíntesis , Neuropéptidos/análisisRESUMEN
The distribution of the entomogenous fungus Antennopsis gallica is extended with its discovery on Reticulitermes flavipes (Kollar) in Canada. The level of infection varied between termite castes. The most heavily infected termites were those that belonged to terminal, nonmoulting castes, soldiers and neotenic reproductives being more infected than workers and nymphs. Several termites carried in excess of 200 fungal thalli, with a maximum number of 479 thalli occurring on a single neotenic reproductive. The distribution of the fungus on termite cuticle appears to be random, with larger body regions supporting proportionately larger numbers of fungal thalli. The fungus was observed in different stages of development, with over 50% occurring as fungal holdfasts and fewer than 10% with fully developed conidiophores. There was no indication that termite health was compromised by the presence of this ectoparasitic fungus.