Coexistence of Liquid Phases in the Sodium Polyphosphate–Chromium Nitrate–Water System

Azevedo, Marcelo Mantovani Martiniano de; Bueno, Maria Izabel M. S.; Davanzo, Celso U.; Galembeck, Fernando

doi:10.1006/jcis.2001.8201

Cited by 8 publications

(4 citation statements)

References 23 publications

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“…Might polyP serve a similar role as an intrinsically unstructured biopolymer capable of making nonspecific interactions? In vitro studies of the polyP polymer indicate that it can demix from solution to form diverse materials, including phase-separated liquid droplets in the presence of some cations, hydrogels, amorphous glasses, and crystals (38,39). Where on the phase spectrum polyP exits in cells is not known; the biophysical properties of polyP granules may also vary with time during starvation.…”

Section: Discussionmentioning

confidence: 99%

Polyphosphate granule biogenesis is temporally and functionally tied to cell cycle exit during starvation in Pseudomonas aeruginosa

Racki

Tocheva

Dieterle

et al. 2017

Proc. Natl. Acad. Sci. U.S.A.

111

112

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Polyphosphate (polyP) granule biogenesis is an ancient and ubiquitous starvation response in bacteria. Although the ability to make polyP is important for survival during quiescence and resistance to diverse environmental stresses, granule genesis is poorly understood. Using quantitative microscopy at high spatial and temporal resolution, we show that granule genesis in Pseudomonas aeruginosa is tightly organized under nitrogen starvation. Following nucleation as many microgranules throughout the nucleoid, polyP granules consolidate and become transiently spatially organized during cell cycle exit. Between 1 and 3 h after nitrogen starvation, a minority of cells have divided, yet the total granule number per cell decreases, total granule volume per cell dramatically increases, and individual granules grow to occupy diameters as large as ∼200 nm. At their peak, mature granules constitute ∼2% of the total cell volume and are evenly spaced along the long cell axis. Following cell cycle exit, granules initially retain a tight spatial organization, yet their size distribution and spacing relax deeper into starvation. Mutant cells lacking polyP elongate during starvation and contain more than one origin. PolyP promotes cell cycle exit by functioning at a step after DNA replication initiation. Together with the universal starvation alarmone (p)ppGpp, polyP has an additive effect on nucleoid dynamics and organization during starvation. Notably, cell cycle exit is temporally coupled to a net increase in polyP granule biomass, suggesting that net synthesis, rather than consumption of the polymer, is important for the mechanism by which polyP promotes completion of cell cycle exit during starvation.ost of our understanding of bacterial physiology comes from laboratory studies of bacteria growing under nutrientrich conditions. However, in many environments, bacteria face dramatic fluctuations in nutrient conditions, including long periods of scarcity when they survive in a nonproliferative stationary state. Although eukaryotic cells and some bacteria have discrete cell cycle checkpoints, many fast-growing bacterial species have uncoupled DNA replication and cell division. They use multifork DNA replication to achieve a doubling time that is faster than the time required to copy the chromosome, giving them a competitive edge in nutrient-replete conditions. This strategy requires distinct regulatory mechanisms and comes at a considerable cost when there is a rapid downshift in nutrient availability: stalled open DNA replication forks are vulnerable to potentially lethal double-stranded DNA breaks (1). Therefore, the ability to reallocate resources under such conditions to prioritize completion of DNA replication is critical for survival. Prioritizing chromosome remodeling and compaction by starvation-specific nucleoid structural proteins is also important during such transitions because resources for DNA repair become limited in deep starvation (2-4). Operating an uncoupled cell cycle, where growth, DNA replication, and cell ...

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Section: Discussionmentioning

confidence: 99%

Polyphosphate granule biogenesis is temporally and functionally tied to cell cycle exit during starvation in Pseudomonas aeruginosa

Racki

Tocheva

Dieterle

et al. 2017

Proc. Natl. Acad. Sci. U.S.A.

111

112

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“…In materials preparation, polyphosphates have been used to produce metal polyphosphate gels from which different interesting products may be obtained. Gel formation is being studied as the result of a liquid−liquid phase separation. − If high polyphosphate concentrations (>2 mol/L) are used, an interesting phenomenon may be observed connected also with liquid−liquid phase separation: the addition of electrolytes generally leads to the separation of two liquid phases with different densities (the same effect may be observed by the addition of a low dielectric constant solvent to mixtures of aqueous solutions of sodium polyphosphate and alkaline earth chlorides). The less dense liquid is the “equilibrium liquid” supposed to contain short polyphosphate chains.…”

Section: Introductionmentioning

confidence: 99%

Spectroscopic Study and Local Coordination of Polyphosphate Colloidal Systems

et al. 2005

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The interaction between metaphosphate chains and the metal ions Ca2+ and Eu3+ has been studied in water by Eu3+ luminescence, infrared absorption, and 31P NMR spectroscopy. Two main families of sites could be identified for the metal ions in the aqueous polyphosphate colloidal systems: (1) cagelike sites provided by the polyphosphate chain and (2) a family which arises following saturation of cagelike sites. Occupation of this second family leads to supramolecular interactions between polyphosphate chains and the consequent destabilization of the colloidal system. In the polyphosphate-Ca2+ system, this destabilization appears as a coacervation process. Equilibrium existing between colloidal species as a function of the compositions could be reasoned based on the spectroscopic measurements. The determination of coordination numbers and the correlation of the results with the observation of coacervates show that Eu3+ luminescence properties can be used to probe in a unique way the coacervation process.

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“…However, the formation of the amorphous aluminum phosphates referred to this work is rather a liquid-liquid phase separation, where the particles are made out of concentrated and highly viscous liquid phase contacting a dilute phase. Direct evidence on phosphate liquid-liquid phase separation is observed in Cr 3+ -polyphosphate-H 2 O system 48 where a dark green aqueous phase is formed contacting a clear phase. Other related evidence is the formation of thermoreversible gels, 49,50 in which ionic electric conductance is essentially unaltered by gel formation, showing that there is little ion immobilization, if any.…”

Section: Formation: Thermodynamics and Mechanismsmentioning

confidence: 99%

Hydrous non-crystalline phosphates: structure, function and a new white pigment

Rosseto¹,

Santos²,

Galembeck³

2006

J. Braz. Chem. Soc.

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Sólidos inorgânicos não-cristalinos hidratados são em grande parte negligenciados devido a pouca compreensão de suas complexas propriedades físico-químicas e estruturais. Apesar disso, eles apresentam uma química muito rica e vasta, de interesse tanto do ponto de vista científico como tecnológico. Este trabalho resenha as características gerais dos sólidos não-cristalinos hidratados, com ênfase especial nos (poli)fosfatos de alumínio. Variações nos precursores e concentração, temperatura, envelhecimento e pH da reação de formação podem propiciar a formação de uma miríade de funções e compostos diferenciados. Produtos adequados a diferentes aplicações, todos eles fosfatos de alumínio amorfos, exemplificam o enorme potencial dos sólidos não-cristalinos.Hydrated non-crystalline inorganic solids are often neglected due to the limited comprehension of their complex physico-chemical and structural properties. However, these non-crystalline materials exhibit a rich and varied chemistry, interesting for scientific and technological reasons. This work reviews general aspects of formation of hydrated non-crystalline solids, with special emphasis on aluminum (poly)phosphate materials. Precursors and concentration variations, temperature, ageing and reaction pH are trivial synthetic variables, but they promote the formation of a myriad of compounds adequate for many functions. Amorphous aluminum phosphates are widely employed in different industrial applications, providing good examples of the potential of hydrous amorphous solids.

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Coexistence of Liquid Phases in the Sodium Polyphosphate–Chromium Nitrate–Water System

Cited by 8 publications

References 23 publications

Polyphosphate granule biogenesis is temporally and functionally tied to cell cycle exit during starvation in Pseudomonas aeruginosa

Polyphosphate granule biogenesis is temporally and functionally tied to cell cycle exit during starvation in Pseudomonas aeruginosa

Spectroscopic Study and Local Coordination of Polyphosphate Colloidal Systems

Hydrous non-crystalline phosphates: structure, function and a new white pigment

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