Cell Stress by Phosphate of Two Protozoa &amp;lt;i&amp;gt;Tetrahymena thermophile&amp;lt;/i&amp;gt; and &amp;lt;i&amp;gt;Tetrahymena pyriformis&amp;lt;/i&amp;gt;

Papa Daouda Mar,Aurelio Serrano,Jose Roman Perez-Castiñeira,Bouchra El Khalfi,Abdelaziz Soukri

doi:10.4236/abb.2017.812033

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.

Highlights

Phosphorus is an essential element of cellular metabolism
Phosphorus is involved in several pathologies: in human with bone and kidney diseases, in mammals with metabolism disorder, in microorganisms whose phosphorus is involved in cell growth
We primarily focused on the physiological study in a phosphate-poor medium of two models Tetrahymena thermophila and Tetrahymena pyriformis, following the mobility, the growth and the morphology of cells

Summary

Introduction

Phosphorus is an essential element of cellular metabolism. It is an important component of cells structure, incorporating in the skeleton of molecules to form phosphate groups such as adenosine triphosphate (ATP), nucleic acids (DNA, RNA), phospholipids and phosphoproteins of animals and plants cells. In Humans, inorganic phosphate is involved in various pathological disorders such as bone, kidney, and vascular calcification [2]. A deficiency of phosphate is found in rickets disease from children, osteomalacia in adults and. It is shown that a low phosphate diet alters glucose metabolism [5] [6] and the expression of insulin-sensitive genes [7] [8]. A deficiency of phosphate in the culture medium induces a cell cycle arrest in Saccharomyces cerevisae [10]

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Conclusion