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Polyphosphate affects cytoplasmic and chromosomal dynamics in nitrogen-starved Pseudomonas aeruginosa

Magkiriadou, S. and Habel, A. and Stepp, W. L. and Newman, D. K. and Manley, S. and Racki, L. R. (2021) Polyphosphate affects cytoplasmic and chromosomal dynamics in nitrogen-starved Pseudomonas aeruginosa. . (Unpublished)

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Polyphosphate (polyP) synthesis is a ubiquitous stress and starvation response in bacteria. In diverse species, mutants unable to make polyP have a wide variety of physiological defects, but the mechanisms by which this simple polyanion exerts its effects remain unclear. One possibility is that polyP’s many functions stem from global effects on the biophysical properties of the cell. We characterize the effect of polyphosphate on cytoplasmic mobility under nitrogen-starvation conditions in the opportunistic pathogen Pseudomonas aeruginosa. Using fluorescence microscopy and particle tracking, we characterize the motion of chromosomal loci and free tracer particles in the cytoplasm. In the absence of polyP and upon starvation, we observe an increase in mobility both for chromosomal loci and for tracer particles. Tracer particles reveal that polyP also modulates the partitioning between a ‘more mobile’ and a ‘less mobile’ population: small particles in cells unable to make polyP are more likely to be ‘mobile’ and explore more of the cytoplasm, particularly during starvation. We speculate that this larger freedom of motion may be a consequence of nucleoid decompaction, which we also observe in starved cells deficient in polyP. Our observations suggest that polyP limits cytoplasmic mobility and accessibility during nitrogen starvation, which may help to explain the pleiotropic phenotypes observed in the absence of polyP.

Item Type:Report or Paper (Discussion Paper)
Related URLs:
URLURL TypeDescription Paper ItemCode
Magkiriadou, S.0000-0001-7660-5012
Stepp, W. L.0000-0001-9818-0377
Newman, D. K.0000-0003-1647-1918
Manley, S.0000-0002-4755-4778
Additional Information:The copyright holder for this preprint is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made available under a CC-BY-NC 4.0 International license. This version posted December 23, 2021. We thank the Center for Environmental Microbial Interactions (CEMI) at Caltech, where the project was conceived. We are grateful to all members of the Manley and Racki groups for insightful discussions, and to Ravi Chawla for testing our tracking parameters on carbon starvation data. Funding was received from the European Research Council (ERC CoG 819823, Piko to Su.M. and So.M.), the Swiss National Science Foundation (182429 to Su.M. and W.S.), and the Donald E. and Delia B. Baxter Foundation Fellowship (L.R.R.) This is manuscript #30145 from The Scripps Research Institute. The authors have declared no competing interest.
Group:Caltech Center for Environmental Microbial Interactions (CEMI)
Funding AgencyGrant Number
European Research Council (ERC)819823
Swiss National Science Foundation (SNSF)182429
Donald E. and Delia B. Baxter FoundationUNSPECIFIED
Subject Keywords:bacterial starvation response; polyphosphate; chromosome mobility; cytoplasmic diffusion
Record Number:CaltechAUTHORS:20220104-461622500
Persistent URL:
Official Citation:Polyphosphate affects cytoplasmic and chromosomal dynamics in nitrogen-starved Pseudomonas aeruginosa. S. Magkiriadou, A. Habel, W. L. Stepp, D. K. Newman, S. Manley, L. R. Racki. bioRxiv 2021.12.23.473106; doi:
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:112657
Deposited By: Tony Diaz
Deposited On:04 Jan 2022 19:57
Last Modified:25 Jul 2022 23:14

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