ABSTRACT
This chapter highlights biochemical evidence from studies of invertebrates where some issues have been experimentally addressed. At the organismic level, quiescence is induced by an unfavorable environmental condition desiccation, anoxia and temperature extremes. Included are states like estivation, hibernation, anaerobic dormancy, and anhydrobiosis. Invertebrate biologists also distinguish a second state called diapause, which also results in metabolic and/or developmental arrest. If the changes in ATP level and pH during quiescence suppress the ubiquitination process, it should be possible to detect differences in levels of ubiquitin-protein conjugates in aerobic versus quiescent embryos. Resting stages have been reported in virtually every major phylum of invertebrates, with the exception of Echinodermata. One molecular mechanism potentially underlying changes in macromolecular stability during quiescence is the suppression of rates of degradation. Quiescence is a term commonly used to indicate an organism, tissue, or cell that displays a reversible transition into a state of developmental and/or metabolic arrest.
