Elk

366 the molt cycle serve to synchronize the many steps and processes that occur. It must be noted that ( -ecdysone does not act directly on genes; rather, it binds with receptors in the nuclear membrane causing release of second messengers (e.g., cyclic AMP) whose action then stimulates gene expression.

Though the modifying influence of juvenile hormone on ecdysone effects has been known for a considerable time (Chapter 21, Section 6.1), it has been shown only recently that it, too, acts on the genome. Its effect is to program the epidermis to secrete a cuticle characteristic of the juvenile stage. Like (3-ecdysone, juvenile hormone binds with nuclear receptors to precipitate, via a second messenger, reactions leading to gene expression.

Bursicon, like ecdysone, affects many processes, though all are related to tanning and melanization of the cuticle. Bursicon's primary effect appears to be to increase the permeability of the hemocyte wall to tyrosine and the epidermal cell wall to dopamine. The hormone may exert this effect via a cyclic AMP-mediated system. In addition, bursicon may activate a tyrosinase in hemocytes, which catalyzes the oxidation of tyrosine to dopa.

Finally, ecdysis is regulated by an eclosion hormone secreted by the brain in silk moths (Chapter 21, Section 6.2) and wax synthesis and endocuticle deposition require the presence of the corpus allatum/corpus cardiacum complex in Calpodes ethlius.

Beekeeping for Beginners

Beekeeping for Beginners

The information in this book is useful to anyone wanting to start beekeeping as a hobby or a business. It was written for beginners. Those who have never looked into beekeeping, may not understand the meaning of the terminology used by people in the industry. We have tried to overcome the problem by giving explanations. We want you to be able to use this book as a guide in to beekeeping.

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