TITLE:
Cell Stress by Phosphate of Two Protozoa Tetrahymena thermophile and Tetrahymena pyriformis
AUTHORS:
Papa Daouda Mar, Bouchra El Khalfi, Jose Roman Perez-Castiñeira, Aurelio Serrano, Abdelaziz Soukri
KEYWORDS:
Phosphorus, Pyrophosphatases, NBRIP, Tetrahymena
JOURNAL NAME:
Advances in Bioscience and Biotechnology,
Vol.8 No.12,
December
6,
2017
ABSTRACT: Phosphorus
is one of the bioelements most needed as a compound cell by living organisms.
Phosphorus is involved in several pathologies: in human with bone and kidney
diseases, in mammals with metabolism disorder (glucose, insulin···), in
microorganisms whose phosphorus is involved in cell growth. Phosphorus has various forms including
pyrophosphate, a by-product of multiple pathways of biosynthesis. Enzymes that
hydrolyze pyrophosphate are called inorganic pyrophosphatases (PPases). Two
major types of inorganic pyrophosphatases are distinguished: the soluble
pyrophosphatases (sPPases) and the membrane pyrophosphatases (mPPases or H+/Na+-PPases).
They play a key role in the control of intracellular inorganic pyrophosphate
level and produce an important ions gradient (H+ or Na+)
to the cells. In this work, we primarily focused on the physiological study in
a phosphate-poor medium of two models Tetrahymena thermophile and Tetrahymena pyriformis,
following the mobility, the growth and the morphology of cells. Secondly, we
evaluated the enzymatic activity of soluble and membrane pyrophosphatases in
both species grown in the same complex medium. A decrease of cell growth is
correlated with unusual morphologies and different mobility in the stress
medium. The measurement of soluble and membrane inorganic pyrophosphatases
activities also shows a decrease which illustrates the lack of phosphate found
in the stress medium. Deficiency of phosphate is a limiting factor for
protozoan growth. These results indicate that Tetrahymena can be used as a model of cellular stress
and consists of a target to study
inorganic pyrophosphatases for a better understanding of phosphate cycle in
higher organisms.