Quantitative analysis of the elemental composition and the mass of bacterial polyphosphate bodies using STEM EDX

The quantitative analysis of laboratory grown organisms (Plectonema boryanum and Staphylococcus aureus) revealed that a typical in vivo polyphosphate body (PPB) contains O (4.3 x 10(-8) microg), C (1.2 x 10(-8) microg), P (6.7 x 10(-9) microg), Mg (1.3 x 10(-9) microg), Ca (6.7 x 10(-10) microg), K (6.7 x 10(-10) microg), Fe (6.0 x 10(-10) microg), S (5.4 x 10(-10) microg) and Al (5.9 x 10(-10) microg). Quantitative X-ray analysis of samples from nature showed PPB contain O (1.63 x 10(-8) microg), C (4.75 x 10(-9) microg), P (2.50 x 10(-9) microg), Mg (5.0 x 10(-10) microg), Ca (2.50 x 10(-10) microg), K (2.50 x 10(-10) microg), Fe (2.25 x 10(-10) microg) and S (2.0 x 10(-10) microg). The mass of an average polyphosphate body was 6.7 x 10(-8) microg for P. boryanum, 2.5 x 10(-8) microg for S. aureus and for microbes from the natural environment 6.3 x 10(-8) microg. The results indicate that the PPB may have other unknown functions in addition to essential element storage, acting as a detoxification method by sequestering heavy metals and providing a homeostasis system in the cell.