Adaptation of the nematode Caenorhabditis elegans to extreme osmotic stress

被引:110
作者
Lamitina, ST
Morrison, R
Moeckel, GW
Strange, K
机构
[1] Vanderbilt Univ, Med Ctr, Dept Anesthesiol, Nashville, TN 37232 USA
[2] Vanderbilt Univ, Med Ctr, Dept Mol Physiol & Biophys, Nashville, TN 37232 USA
[3] Vanderbilt Univ, Med Ctr, Dept Pathol, Nashville, TN 37232 USA
来源
AMERICAN JOURNAL OF PHYSIOLOGY-CELL PHYSIOLOGY | 2004年 / 286卷 / 04期
关键词
hypertonicity; glycerol; cell volume regulation;
D O I
10.1152/ajpcell.00381.2003
中图分类号
Q2 [细胞生物学];
学科分类号
071009 ; 090102 ;
摘要
The ability to control osmotic balance is essential for cellular life. Cellular osmotic homeostasis is maintained by accumulation and loss of inorganic ions and organic osmolytes. Although osmoregulation has been studied extensively in many cell types, major gaps exist in our molecular understanding of this essential process. Because of its numerous experimental advantages, the nematode Caenorhabditis elegans provides a powerful model system to characterize the genetic basis of animal cell osmoregulation. We therefore characterized the ability of worms to adapt to extreme osmotic stress. Exposure of worms to high-salt growth agar causes rapid shrinkage. Survival is normal on agar containing up to 200 mM NaCl. When grown on 200 mM NaCl for 2 wk, worms are able to survive well on agar containing up to 500 mM NaCl. HPLC analysis demonstrated that levels of the organic osmolyte glycerol increase 15- to 20-fold in nematodes grown on 200 mM NaCl agar. Accumulation of glycerol begins 3 h after exposure to hypertonic stress and peaks by 24 h. Glycerol accumulation is mediated primarily by synthesis from metabolic precursors. Consistent with this finding, hypertonicity increases transcriptional expression of glycerol 3-phosphate dehydrogenase, an enzyme that is rate limiting for hypertonicity- induced glycerol synthesis in yeast. Worms adapted to high salt swell and then return to their initial body volume when exposed to low-salt agar. During recovery from hypertonic stress, glycerol levels fall rapidly and glycerol excretion increases approximately fivefold. Our studies provide the first description of osmotic adaptation in C. elegans and provide the foundation for genetic and functional genomic analysis of animal cell osmoregulation.
引用
收藏
页码:C785 / C791
页数:7
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