Publisher Summary This chapter discusses the structure and regulation of the corpus allatum. The corpora allata (CA) are endocrine glands in the posterior regions of the head, or in rare instances in the thorax, which are closely associated with the stomatogastric nervous system. This chapter focuses on the regulation of the CA. It also describes the embryology, innervations, and the relationships of the structure, particularly the ultrastructure, to its synthetic activity. The characteristic shape of the CA is ovoid to round but they may be elongate as in large larvae and adults of Libellula depressa. The size of the glands is frequently about the diameter of the aorta or smaller; however, there is much variation among species and even within a species, size differs with age, sex, polymorphism, and the activity cycle of the glands. Although only one type of glandular cell occurs in the CA, there are a variety of types of CA with respect to the number of cells per gland and the relative size of the cells. The CA are surrounded by a continuous noncellular basal lamina, roughly 0.1-1 μ m thick. This material occasionally projects between two glandular cells into the interior of the gland, forming trabeculae that may accompany nerves and trachea.

Structure and Regulation of the Corpus Allatum

Publisher Summary This chapter discusses the structure and function of major groups of hemolymph proteins that are common to all insects, storage proteins, lipoproteins, vitellogenins, and inducible antibacterial proteins. It also discusses some proteins and peptides that are present in smaller amounts, sometimes occurring only in a few insect species. With the development of microsequencing techniques that can provide information about the sequence of amino acids at the N-terminal end of an intact protein on a sample of less than 20 picomoles, it has become feasible to use one- or two-dimensional polyacrylamide gel electrophoresis (PAGE) a the protein purification method of choice. In many cases, proteins can be transferred directly from gels to derivatized paper or other media and spots cut from the medium can be inserted directly into the sequencer. If necessary, proteins on the medium can be cleaved to peptides, which can be separated by high-pressure liquid chromatography (HPLC) or by PAGE.

Insect Haemolymph Proteins

The Juvenile Hormones

Juvenile hormones play a crucial role in development, metamorphosis, and reproduction of insects. This mini-review discusses the nature of the juvenile hormones identified in insects and their changes in concentration in the hemolymph during development and reproduction. The hemolymph titer is largely determined by the rate at which juvenile hormones are synthesized and released by the corpora allata, but other factors are also involved in titer regulation, such as the affinity and concentration of juvenile hormone binding proteins in the hemolymph and the rate of juvenile hormone degradation in hemolymph and tissues. Juvenile hormone specific esterases occur in hemolymph and tissues, whereas epoxide hydrolases, which may degrade the hormone, are exclusively tissue bound. The activities of these degradative enzymes and the concentration of binding proteins change during the insect life cycle and these changes are related to fluctuations in hormone titer. However, we are still a long way from understanding the subtle interactions between these components in regulation of juvenile hormone titers. In particular, our knowledge is hampered by lack of information about the types, concentrations, and affinities of intracellular juvenile hormone receptors. © 1996 Wiley-Liss, Inc.

Regulation of JH titers: The relevance of degradative enzymes and binding proteins

https://ucanr.edu/sites/hammocklab/files/130996.pdf

Maria Rudnicka

Papers

Purification of the juvenile hormone esterase from the haemolymph of the wax moth Galleria mellonella (lepidoptera)

Hydrolysis and binding of the juvenile hormone in the haemolymph of Galleria mellonella

Approaches to the purification of the juvenile hormone esterase from the cabbage looper, Trichoplusia ni

Tissue specific juvenile hormone degradation in Galleria mellonella