About this Research Topic
Forty-five years ago, Starratt and Brown determined the first structure of the insect pentapeptide hormone proctolin. Since that historic event, the field has expanded, and various groups have characterized, sequenced, and genetically engineered many insect peptides. One of the central advances of the field was the advent of electron microscopy, and in using this technique, it was possible to show synapse-like contacts between peptidergic neurons in the corpus allatum. This indicated that these peptides are capable of transmitting signals. Subsequent research showed that these peptide moieties are not only restricted in transmitting signals to endocrine cells, but are also found in somatic cells.
The presence of these peptides was shown in many other sites and tissues, and was confirmed by immunocytochemical studies using specific antibodies in conjunction with biochemical synthesis of these molecules and their analogues. Immunocytochemical studies established that the insect brain contains peptides that resemble mammalian proctolin and insulin. Some of the peptides that were characterized show myotropic, allatotropic, and allatostatic activities that are important for gut movement and controlling moulting. Recent advances identified that many of these peptide-specific receptors are involved in signal transduction, such as in reproduction and digestion. Additionally, ample molecular biology studies show that many of these peptides are cleavage products of larger protein precursors produced from specific messenger RNA molecules by post translational processing that release these active peptide moieties. The wide distribution of these regulatory peptides and their many analogues that are found in the animal kingdom indicate that they have been preserved in the course of evolution and are encoded by ancestral genes.
Because of the important physiological roles of these peptides, many attempts were made to harness them in order to control agricultural pests and insect vectors by targeting egg development, blood digestion, food digestion, and pheromone production, as well as misdirection to trap insects. These attempts were aided by the advent of organic synthesis and clever molecular biology approaches that allowed the production of ample quantities of these peptides and their analogues in order to facilitate rapid testing for activity against insects for protection against vector and pest insects. Several of these engineered cells producing Trypsin Modulating Oostatic Factor (TMOF) are used to control mosquito larvae and are currently used to reduce mosquito populations transmitting dengue in Asia, while many others are in development to protect plants.
Volume II of this Research Topic welcomes original as well as review articles on the role of peptide hormones in insect physiology, biochemistry, and molecular biology processes. We welcome manuscripts describing new results on the subject that cover insect single peptides including: peptide hormones, antibacterial peptides, signal peptides, and their receptors that control biological events.
Keywords: Peptide Hormones, Immunity, Behavior, Metamorphosis, Diapause.
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