|
| |
|
|
|
|
||||
| Home Help Feedback Subscriptions Archive Search Table of Contents | ||||
Journal of Experimental Biology, Vol 202, Issue 19 2567-2580, Copyright © 1999 by Company of Biologists
JOURNAL ARTICLES |
JE Podrabsky and SC Hand
Department of Environmental, Population, and Organismic Biology, University of Colorado, Boulder, CO 80309-0334, USA. podrabsk@leland. stanford.edu.
The annual killifish Austrofundulus limnaeus inhabits ephemeral ponds that dry out on a seasonal basis, thereby killing the adult and juvenile forms. Populations persist because diapausing embryos become embedded in the pond sediments. The rate of oxygen consumption of diapause II embryos is depressed by up to 90 % compared with that of developing embryos, and a parallel reduction is observed in heart rate. Developmental arrest was identified by cessation of somite proliferation and blockage of the ontogenetic increase in DNA content. Surprisingly, the arrest of metabolism and development is temporally offset as embryos reach diapause II; metabolic rate begins to decline 12 days prior to arrest of development. Release of embryos from diapause II is facilitated by increasing the light phase of the photoperiod. The rate of oxygen consumption of diapause III embryos is 84 % lower than the value preceding diapause III. The total energy flow of diapause II embryos apparently includes a contribution from anaerobic processes on the basis of calorimetric/respirometric ratios that are above the oxycaloric equivalent. Accumulations of lactate and ethanol at the expense of glycogen reserves are small or undetectable and do not account for the excess heat signal. Diapause II embryos maintain high [ATP]/[ADP] ratios and adenylate energy charge during diapause, consistent with a simultaneous depression of energy use and demand. Levels of AMP increase during early development and diapause II despite the highly charged adenylate pool. High values for [AMP]/[ATP] ratios in diapause II embryos are correlated with decreased rates of oxygen consumption and heat dissipation, which suggests a role for AMP in the depression of metabolism during early development and diapause II.
CiteULike 
Complore 
Connotea 
Del.icio.us 
Digg 
Reddit 
Technorati 
Twitter What's this?
This article has been cited by other articles:
|
|
 |
|
  J. A. Reynolds and S. C. Hand Decoupling development and energy flow during embryonic diapause in the cricket, Allonemobius socius J. Exp. Biol., July 1, 2009; 212(13): 2065 - 2074. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. A. Reynolds and S. C. Hand Embryonic diapause highlighted by differential expression of mRNAs for ecdysteroidogenesis, transcription and lipid sparing in the cricket Allonemobius socius J. Exp. Biol., July 1, 2009; 212(13): 2075 - 2084. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 A. Tingaud-Sequeira, C. Zapater, F. Chauvigne, D. Otero, and J. Cerda Adaptive plasticity of killifish (Fundulus heteroclitus) embryos: dehydration-stimulated development and differential aquaporin-3 expression Am J Physiol Regulatory Integrative Comp Physiol, April 1, 2009; 296(4): R1041 - R1052. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. E. Podrabsky, J. P. Lopez, T. W. M. Fan, R. Higashi, and G. N. Somero Extreme anoxia tolerance in embryos of the annual killifish Austrofundulus limnaeus: insights from a metabolomics analysis J. Exp. Biol., July 1, 2007; 210(13): 2253 - 2266. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. A. Menze, M. J. Clavenna, and S. C. Hand Depression of cell metabolism and proliferation by membrane-permeable and -impermeable modulators: role for AMP-to-ATP ratio Am J Physiol Regulatory Integrative Comp Physiol, February 1, 2005; 288(2): R501 - R510. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 T. G. Nystul, J. P. Goldmark, P. A. Padilla, and M. B. Roth Suspended Animation in C. elegans Requires the Spindle Checkpoint Science, November 7, 2003; 302(5647): 1038 - 1041. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. E. Podrabsky, J. F. Carpenter, and S. C. Hand Survival of water stress in annual fish embryos: dehydration avoidance and egg envelope amyloid fibers Am J Physiol Regulatory Integrative Comp Physiol, January 1, 2001; 280(1): R123 - R131. [Abstract] [Full Text] [PDF]
|
|
