QUICK SEARCH:   [advanced] Author: Keyword(s):
Home     Help     Feedback     Subscriptions     Archive     Search     Table of Contents

This Article Full Text (PDF) References Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Warner, A. Articles by Clegg, J. Search for Related Content PubMed PubMed Citation Articles by Warner, A. Articles by Clegg, J. Social Bookmarking                         What's this?

Journal of Experimental Biology, Vol 200, Issue 5 897-908, Copyright © 1997 by Company of Biologists

JOURNAL ARTICLES

Effect of anaerobiosis on cysteine protease regulation during the embryonic-larval transition in

A Warner, S Jackson and J Clegg

Hydrated encysted embryos of the brine shrimp Artemia franciscana have the ability to withstand years in anaerobic sea water using metabolic strategies that enable them to inactivate all cell metabolic activities and then to resume development when placed in aerobic sea water. However, this unique characteristic of Artemia franciscana embryos is lost during a very short period, at the embryonic­larval transition period of development, coincident with the appearance of prenauplius larvae. Thus, while encysted embryos show complete inhibition of proteolysis over at least 4 years under anoxia, control of this activity, together with resistance to anoxia, is lost in newly hatched nauplius larvae after only a few days in anaerobic sea water. In contrast to encysted embryos, young larvae in anaerobic sea water produce large amounts of lactic acid, which reaches a concentration of nearly 50 mmol l-1 within 12 h of incubation. The accumulated lactic acid is believed to reduce the intracellular pH (pHi) to considerably less than 6.3, the value found in encysted embryos after 5 months in anaerobic sea water. We find that larvae, in contrast to embryos, lose cytoplasmic proteins at the rate of 4­5 ng h-1 larva-1 upon transfer to anaerobic sea water, while yolk proteins are not degraded in either embryos or larvae under anoxic conditions. The decline in cytoplasmic protein levels in anaerobic larvae may be due to activation of an endogenous cysteine protease (CP) as the pHi becomes acidic. Contributing to the apparent uncontrolled CP activity is a decrease in the level of cysteine protease inhibitor (CPI) activity during the embryonic­larval transition period, resulting in an increase in the CP/CPI ratio, from approximately 0.5 in embryos to greater than 1.0 in newly hatched larvae. Finally, data are presented to suggest that loss of the 26 kDa stress protein from embryos during the embryonic­larval transition may also contribute to the loss in resistance of young nauplius larvae of A. franciscana to anaerobic conditions.
CiteULike    Complore    Connotea    Del.icio.us    Digg    Reddit    Technorati    Twitter    What's this?

This article has been cited by other articles:

				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]