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Electronic Journal of Biotechnology
Universidad Católica de Valparaíso
ISSN: 0717-3458
Vol. 5, No. 1, 2002, pp. 43-54
Bioline Code: ej02012
Full paper language: English
Document type: Research Article
Document available free of charge

Electronic Journal of Biotechnology, Vol. 5, No. 1, 2002, pp. 43-54

 en Application of rice ( Oryza sativa check for this species in other resources L.) suspension culture in studying senescence in vitro (I). Single strand preferring nuclease activity
Hosseini, Ramin & Mulligan, Bernard J.

Abstract

Single Strand-Preferring Nucleases (SSPNs) have been implicated in the triggering and progress of cell death pathways, including senescence in higher plants, though the biological roles of such enzymes are still obscure. In the present study, heterotrophic cell suspension cultures of Oryza sativa check for this species in other resources L. (rice) cv Taipei 309 were used to investigate changes in Single Strand-Preferring Nuclease activity associated with cell death in vitro. An acid nuclease activity (pH 5.5) was found which was strongly stimulated in the presence of 10 mM Zn2+ and inhibited by 10 mM EDTA and EGTA. An increase in SSPN activity was concomitant with a loss of cell viability, total protein and the onset of stationary phase of growth in the cell cultures. Using DNA-SDS-PAGE two major SSPNs were detected with the molecular weights of 26 KDa and 53.5 KDa. There are possibilities that these two enzymes represent monomeric and dimeric forms of the same nuclease or they are two different enzymes. The 26 KDa nuclease was partially purified using heparin-Sepharose column chromatography. The results confirm the value of plant cell suspension cultures for the investigation of the molecular process underlying plant cell ageing, senescence processes and programmed cell death (PCD). Possible senescence-associated roles of SSPNs are discussed.

Keywords
Programmed Cell Death (PCD), rice, senescence

 
© 2002 by Universidad Católica de Valparaíso -- Chile
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