Structures Containing Polyphosphate in Micrococcus lysodeikticus

Abstract

Granular structures containing inorganic polyphosphate were found in Micrococcus lysodeikticus. These structures were isolated by fractionation of the bacterial extract obtained by lysing the organisms with lysozyme. The composition of the fraction which was enriched with these structures was found to be: protein, 24%; lipids, 30%; and polyphosphate, 27%. This fraction also contained small amounts of ribonucleic acids, carbohydrate, and polyvalent cations. The effect of different reagents and enzymes on the integrity of the granules was examined. It was noticed that they accumulate in the bacteria during the logarithmic phase of growth but disappear gradually during the stationary phase.

Formation of volutin granules inCorynebacterium glutamicum

“…The large intracellular electron-dense granules ( Fig. 2, arrows (a)) resemble those in C. glutamicum MG [6] or in Micrococcus lysodeikticus [23]. They were tentatively assigned to volutin granules.…”

“…1(F). They resembled in size and appearance those aggregates shown in TEM pictures of volutin granular fractions from cells of M. lysodeikticus [23,24]. NMR spectroscopy was used to corroborate that poly P was a major constituent in volutin granules.…”

“…Granular fractions obtained from M. lysodeikticus contained protein [23]. To see whether proteins were also present in the C. glutamicum granules, an SDS-PAGE analysis of the particulate fraction was done.…”

“…Therefore, a more direct role of Mg 2+ ions in poly P complex formation or on the activity of Mg-dependent poly P enzymes seems likely: Mg 2+ is one of the constituents of poly P granules/acidocalcisomes in several bacteria, and in C. glutamicum (as shown in Fig. 3), and stabilizes granule structure during isolation [13,23,25]. Possibly, a similar mechanism was responsible in C. glutamicum for enhanced granule formation during growth in high-Mg medium.…”

Differentiation of polyphosphate and poly-β-hydroxybutyrate granules in an Acinetobacter sp. isolated from activated sludge

“…The second source of confusion relates to the physical nature of the polyphosphate and PHB granules and the difficulties encountered in isolating each type of granule free from other cellular components. Friedberg and Avigad [13] found that the presence of magnesium was essential for the isolation of intact polyphosphate granules from Micrococcus lysodeikticus and that suspension of the intact cells in distilled water or even freezing and thawing led to dissolution of the polyphosphate granules. As pointed out in a review by Sykes [3], this would explain the inability of Martinez [14] to isolate intact granules from various species of Spirillum and the presence of a high concentration of soluble polyphosphate in the supernatant fluid of disrupted cells following centrifugation.…”