Food Uptake And Utilization

by symbiotic microorganisms (Section 5.1.2). During starvation or when present in excess, 507

amino acids may undergo oxidative deamination (i.e., be oxidized and simultaneously lose their a-amino group) within the fat body, resulting in the formation of the corresponding keto acids. The latter can then be further oxidized via the Krebs cycle and respiratory chain to provide energy or may be converted into carbohydrate or fat reserves. The ammonia produced during deamination is normally converted into uric acid.

The fat body is an important site of hemolymph protein synthesis, especially in the late juvenile stages of endopterygotes and in adult female insects. Storage hexamers (so-called because the proteins comprise six homologous subunits) have been characterized from more than 20 species in six orders, mainly Diptera and Lepidoptera (Telfer and Kunkel, 1991). They reach very high concentrations in the hemolymph just before metamorphosis, and are effectively serving as a store of amino acids for use in adult tissue and protein formation. If stored "individually," the amino acids would create a severe osmotic problem for the insect. In silk moth (Bombyx) caterpillars, for example, the hemolymph protein concentration increases sixfold from the fourth to the final instar, in preparation for spinning the cocoon, metamorphosis, and egg production. When the adult emerges, the concentration has fallen to about one-third the value at pupation. During sexual maturation in females of many species, the fat body produces vitellogenins ("female-specific" proteins). These proteins, whose synthesis is regulated by juvenile hormone or ecdysone, are accumulated in large amounts by the developing oocytes (Chapter 19, Section 3.1.1). In female insects that do not feed as adults (e.g., Bombyx), the storage hexamers are the source of the amino acids for vitellogenin production which occurs during the pharate adult stage (Chapter 21, Section 3.3.3). In the males of some species the fat body produces proteins that are accumulated by the accessory reproductive glands, probably for use in spermatophore production. Lipophorins are another important group ofhemolymph proteins synthesized in the fat body. These, often very large, molecules are important in the absorption and transport of lipids and, additionally, serve as coagulogens in hemolymph clotting (Chapter 17, Section 4.2.2).

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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