Trehalose – The Insect ‘Blood’ Sugar


By jpeza - Posted on 12 Enero 2011

Fecha Publicación: 
1 Ene 2003
Nombre de Revista: 
Datos del paper
Autor Principal: 
S. Nelson Thompson
Volumen: 
31
Página Inicial: 
205
Página Final: 
285
Abstract: 

Trehalose, the non-reducing disaccharide of glucose, is the principal sugar
circulating in the blood or haemolymph of most insects. Resistance to acid
hydrolysis and an absence of direct intramolecular hydrogen bonding make
trehalose chemically unique when compared with other common disaccharides,particularly sucrose, the non-reducing disaccharide of plant origin. Synthesized
in the fat body following digestion of dietary sugar, trehalose is a condensation
product of two glycolytic intermediates, glucose-1-phosphate and glucose-
6-phosphate. Alternative sources of trehalose are glycogen breakdown and
gluconeogenesis. Hydrolysis to reform glucose, catalyzed by isozymes of a
single enzyme, trehalase, is the only known pathway of trehalose utilization.
Trehalose synthesis and degradation are under hormonal control involving
both hypertrehalosemic and hypotrehalosemic factors. Trehalose concentration
in the blood, however, is not homeostatically regulated. Rather, trehalose
occurs at highly variable levels, typically between 5 and 50 mM, depending
on environmental conditions, physiological state and nutrition. This variable
concentration is essential for fulfilling the roles of trehalose, as (1) an energy
store, the traditional role ascribed to trehalose; (2) a cryoprotectant, reducing
the supercooling point of some freeze-avoiding insects; (3) a protein stabilizer
during osmotic and thermal stress, a function only recently investigated in
insects, and (4) a component of a feedback mechanism regulating feeding
behaviour and nutrient intake, where blood metabolite levels including
trehalose act through modulation of taste receptor responses and through
the central nervous system to influence food selection. These are all examples of
functional conservation in the absence of homeostasis. This has been termed
enantiostasis, where functional conservation serves as a mechanism of
physiological adaptation despite what appears to be an unstable internal
milieu.

Dirección del Autor: 

Analytical Chemistry Instrumentation Facility and Department of Entomology,
University of California, Riverside, CA 92521, USA

Keywords: 
Trehalose
AdjuntoTamaño
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