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Author (up) Bolanowski, M.A.; Russell, R.L.; Jacobson, L.A. file  url
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  Title Quantitative measures of aging in the nematode Caenorhabditis elegans. I. Population and longitudinal studies of two behavioral parameters Type Journal Article
  Year 1981 Publication Mechanisms of Ageing and Development Abbreviated Journal Mech Ageing Dev  
  Volume 15 Issue 3 Pages 279-295  
  Keywords *Aging; Animals; Body Water/metabolism; Caenorhabditis/*physiology; Defecation; Movement  
  Abstract As a first step in the quantitative characterization of senescence in the nematode Caenorhabditis elegans, we have studied movement wave frequency, defecation frequency, and whole-body water efflux as a function of age. Populations of C. elegans, strain N2, were cultured monoxenically on E. coli lawns at 20 degrees C. The median lifespan in such populations was approximately 12 days. Population mean movement wave frequency declined linearly with age (slope = -4.66 waves/minute per day). The decline in population mean defecation frequency (defecations per minute) was multiphasic, consisting of (1) a rapid decline (slope = -0.233 defecations/minute per day) from day 3 to day 6, (2) no apparent trend from day 6 to day 9, and (3) a gradual decline (slope = -0.089 defecations/minute per day) from 9 to day 14. Animals alive on or after day 15 were not observed to defecate. In longitudinal studies, individual animals exhibited linear declines in movement wave frequency and multiphasic declines in defecation frequency. For future population studies, the age-dependent declines in movement and defecation frequency appear sufficiently large and reproducible to a multiparametric description of senescence in C. elegans. One physiological parameter, 3H2O efflux, was found to be age-independent and to consist of two first-order rates. The half-times of the slow and fast efflux rates were approximately 15 and approximately 2.1 minutes, respectively. The two half-times and the fractions of 3H2O exhibiting the two half-times were invariant with age.  
  Call Number Serial 1022  
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Author (up) Ghars, M.A.; Parre, E.; Debez, A.; Bordenave, M.; Richard, L.; Leport, L.; Bouchereau, A.; Savoure, A.; Abdelly, C. url  openurl
  Title Comparative salt tolerance analysis between Arabidopsis thaliana and Thellungiella halophila, with special emphasis on K(+)/Na(+) selectivity and proline accumulation Type Journal Article
  Year 2008 Publication Journal of Plant Physiology Abbreviated Journal J Plant Physiol  
  Volume 165 Issue 6 Pages 588-599  
  Keywords Arabidopsis/drug effects/growth & development/*metabolism; Biomass; Brassicaceae/drug effects/growth & development/*metabolism; Potassium/*metabolism; Proline/*metabolism; Salinity; *Salt-Tolerance/drug effects; Sodium/*metabolism; Sodium Chloride/pharmacology; Stress, Physiological/drug effects; Water/metabolism  
  Abstract The eco-physiology of salt tolerance, with an emphasis on K(+) nutrition and proline accumulation, was investigated in the halophyte Thellungiella halophila and in both wild type and eskimo-1 mutant of the glycophyte Arabidopsis thaliana, which differ in their proline accumulation capacity. Plants cultivated in inert sand were challenged for 3 weeks with up to 500mM NaCl. Low salinity significantly decreased A. thaliana growth, whereas growth restriction was significant only at salt concentrations equal to or exceeding 300mM NaCl in T. halophila. Na(+) content generally increased with the amount of salt added in the culture medium in both species, but T. halophila showed an ability to control Na(+) accumulation in shoots. The analysis of the relationship between water and Na(+) contents suggested an apoplastic sodium accumulation in both species; this trait was more pronounced in A. thaliana than in T. halophila. The better NaCl tolerance in the latter was associated with a better K(+) supply, resulting in higher K(+)/Na(+) ratios. It was also noteworthy that, despite highly accumulating proline, the A. thaliana eskimo-1 mutant was the most salt-sensitive species. Taken together, our findings indicate that salt tolerance may be partly linked to the plants' ability to control Na(+) influx and to ensure appropriate K(+) nutrition, but is not linked to proline accumulation.  
  Call Number Serial 230  
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