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Vanadate-sensitive mutants of Hansenula polymorpha

Tagliapietra Orciani, Alessandro and Guerra, Emanuela and Mannazzu, Ilaria Maria (1999) Vanadate-sensitive mutants of Hansenula polymorpha. Current Genetics, Vol. 35 (3-4), p. 456. eISSN 1432-0983. Article.

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DOI: 10.1007/BF02743091

Abstract

The mechanisms by which vanadate can affect important metabolic processes, such as cell growth and morphogenesis, are not fully understood. This is due to the variety of intracellular targets of the metal, and to the changes in chemical form and oxidation state that vanadium can undergo, both in the external environment and intracellularly. The yeast Hansenula polymorpha represents an interesting model for studies concerning vanadate tolerance. This yeast is able to grow on vanadate concentrations which are lethal to other organisms, showing at the same time ultrastructural and physiological modifications which suggest the existance of a vanadate-sensitive target in the invertase route to the plasma membrane, and the involvement of vacuoles in the activation of a detoxification mechanism for vanadate (Mannazzu et al 1997, 1998). In order to further understand the mechanisms responsible for this vanadate-tolerance in H. polymorpha, we isolated 61 vas (vanadate sensitive) mutants, characterized by altered sensitivity to vanadate. Fifty-four of these mutants, which show a recessive phenotype and are currently being subjected to complementation analysis, were tested for the expression of additional phenotypes related to defects in metal ion homeostasis and/or vacular functions. Interestingly, 24 of them are vas cos (copper sensitive) and 2 are vas cos vpa (vacuolar proteolitic activity defective), thus suggesting the existance of common determinants in the detoxification of vanadate and copper, and confirming the important role for vacuoles in the homeostatic control of metal ions. The isolation of the genes involved in vanadate tolerance is in progress.

Item Type:Article
ID Code:3833
Status:Published
Refereed:Yes
Uncontrolled Keywords:Hansenula polymorpha, yeasts, vanadate-sensitive mutants
Subjects:Area 07 - Scienze agrarie e veterinarie > AGR/16 Microbiologia agraria
Divisions:001 Università di Sassari > 01 Dipartimenti > Scienze ambientali agrarie e biotecnologie agro-alimentari
Publisher:Springer Berlin / Heidelberg
eISSN:1432-0983
Additional Information:Poster presented at the 19th International Conference on Yeast Genetics and Molecular Biology, Rimini, Italy, 25–30 May 1999.
Deposited On:05 May 2010 13:22

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