Proliferative ability in Phytomonas Jma and correlation with the endogenous concentration of polyamines

MARCORA M.S; GONZALEZ, N.S; ZADIKIAN C; CARRILLO C; ALGRANATI I.D

Villa Carlos Paz, Cordoba

Congreso; XLIV Reunión Anual de la Sociedad Argentina de Investigación en Bioquímica y Biología Molecular; 2008

Polyamines are fundamental for cell survival and proliferation; putrescine and spermidine being the most abundant in trypanosomatids. Putrescine can be synthesized from ornithine by ornithine decarboxylase (ODC), while spermidine derivates from putrescine via spermidine synthase. ODC activity was detected in phytomonads extracts and this activity was inhibited by DFMO. Incubation with radioactive ornithine followed by electrophoretic analysis showed a stoichiometric equivalence between the amount of putrescine synthesis and the release of CO2, confirming the presence of ODC activity. In order to analyze the role of polyamines in Phytomonas Jma they were cultivated in semisynthetic medium (SDM) in the presence or the absence of DFMO, showing in both cases a continuous growth. When levels of endogenous polyamines were measured by HPLC, the presence of DFMO in the medium caused an almost complete disappearance of putrescine while the concentration of spermidine was partially reduced . These results suggested that putrescine is not essential, because its absence did not affect the growth. On the other hand, when parasites were grown in the presence of both DFMO and CHA (spermidine synthase inhibitor) the growth was remarkably reduced wich correlated with very low levels of both putrescine and spermidine. This confirms that spermidine is essencial for Phytomonas Jma proliferation.