Toxoplasma gondii: Over-expression of lactate dehydrogenase enhances differentiation under alkaline conditions

Toxoplasma gondii, an intracellular parasite, has two distinctive growth stages, namely rapidly growing tachyzoites and slowly growing bradyzoites. Here we report a unique physiological function of the last committed glycolytic enzyme of T. gondii, lactate dehydrogenase (TgLDH), which is present in...

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Bibliographic Details
Published in:Experimental parasitology 2009-06, Vol.122 (2), p.155-161
Main Authors: Liwak, Urszula, Ananvoranich, Sirinart
Format: Article
Language:English
Subjects:
Animals
Animals, Genetically Modified
Biological and medical sciences
Blotting, Western
Cells, Cultured
Differentiation
Enzymatic activity
Fibroblasts - parasitology
Fluorescent Antibody Technique
Foreskin - cytology
Fundamental and applied biological sciences. Psychology
Gene Expression Regulation, Enzymologic
Humans
Hydrogen-Ion Concentration
L-Lactate Dehydrogenase - biosynthesis
L-Lactate Dehydrogenase - genetics
L-Lactate Dehydrogenase - physiology
Lactate dehydrogenase
Life cycle. Host-agent relationship. Pathogenesis
Male
Protozoa
Recombinant Proteins - biosynthesis
Recombinant Proteins - genetics
Toxoplasma - cytology
Toxoplasma - enzymology
Toxoplasma - genetics
Toxoplasma - growth & development
Toxoplasma gondii
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Summary:Toxoplasma gondii, an intracellular parasite, has two distinctive growth stages, namely rapidly growing tachyzoites and slowly growing bradyzoites. Here we report a unique physiological function of the last committed glycolytic enzyme of T. gondii, lactate dehydrogenase (TgLDH), which is present in two isoforms and expressed in a stage-specific manner. TgLDH1 is present in tachyzoites while TgLDH2 is found in bradyzoites. Using clonal transgenic parasites over-expressing either TgLDH1 or TgLDH2, we showed that the enzymatic activity, growth, and virulence of tachyzoites were unaffected by the presence of the recombinant protein. Interestingly, under alkaline conditions the presence of the recombinant TgLDH proteins increased the differentiation, as detected by the formation of cyst structures in vitro, while green fluorescent protein did not. The differentiation enhancement of the recombinant TgLDH1 and TgLDH2 strongly suggests that TgLDH1 and TgLDH2 have an important physiological function, in addition to being glycolytic enzymes and differentiation markers.
ISSN:0014-4894
1090-2449
DOI:10.1016/j.exppara.2009.01.016