scholarly journals Single-cell growth inference of Corynebacterium glutamicum reveals asymptoticallylinear growth

eLife ◽  
2021 ◽  
Vol 10 ◽  
Author(s):  
Joris Jan Boudewijn Messelink ◽  
Fabian Meyer ◽  
Marc Bramkamp ◽  
Chase P Broedersz
Keyword(s):  
Cell Growth ◽  
Single Cell ◽  
Corynebacterium Glutamicum ◽  
Cell Size ◽  
Linear Growth ◽  
Growth Dynamics ◽  
Growth Mode ◽  
Bacterial Cells ◽  
Asymptotically Linear ◽  
Regulation Of Growth

Regulation of growth and cell size is crucial for the optimization of bacterial cellular function. So far, single bacterial cells have been found to grow predominantly exponentially, which implies the need for tight regulation to maintain cell size homeostasis. Here, we characterize the growth behavior of the apically growing bacterium Corynebacterium glutamicum using a novel broadly applicable inference method for single-cell growth dynamics. Using this approach, we find that C. glutamicum exhibits asymptotically linear single-cell growth. To explain this growth mode, we model elongation as being rate-limited by the apical growth mechanism. Our model accurately reproduces the inferred cell growth dynamics and is validated with elongation measurements on a transglycosylase deficient ΔrodA mutant. Finally, with simulations we show that the distribution of cell lengths is narrower for linear than exponential growth, suggesting that this asymptotically linear growth mode can act as a substitute for tight division length and division symmetry regulation.

scholarly journals Single-cell growth inference of Corynebacterium glutamicum reveals asymptotically linear growth

2020 ◽  
Author(s):  
Joris Messelink ◽  
Fabian Meyer ◽  
Marc Bramkamp ◽  
Chase P. Broedersz
Keyword(s):  
Cell Growth ◽  
Single Cell ◽  
Corynebacterium Glutamicum ◽  
Cell Size ◽  
Linear Growth ◽  
Growth Dynamics ◽  
Asymptotically Linear ◽  
Inference Method ◽  
Growth Modes ◽  
Regulation Mechanisms

AbstractIn many bacteria, protein mass production is thought to be rate limiting for growth, implying exponential growth at the single cell level. To maintain cell-size homeostasis in proliferating populations of exponentially growing bacteria, tight growth and division mechanisms are required. However, it remains unclear whether these considerations set universal physical limits to bacterial growth. Here, we characterize the growth dynamics of the actinobacterium Corynebacterium glutamicum - a promising candidate for uncovering novel growth modes. This bacterium exhibits apical cell wall synthesis and division site selection systems appear to be absent, as reflected by a broad distribution of division asymmetries. We develop a novel growth inference method that averages out measurement noise and single-cell variability to obtain elongation rate curves as a function of birth length. Using this approach, we find that C. glutamicum exhibits asymptotically linear single-cell growth. To explain this growth mode, we model elongation as being rate-limited by the apical growth mechanism mediated by cell wall transglycosylases. This model accurately reproduces the observed elongation rate curves, and we further validate the model with growth measurements on a transglycosylase deficient ΔrodA mutant. Finally, with simulations we show that asymptotically linear growth yields a narrower distribution of cell lengths, suggesting that this growth mode can act as a substitute for tight division length and division symmetry regulation.SignificanceRegulation of growth and cell size is crucial for the optimization of bacterial cellular function. So far, single bacterial cells have been found to grow exponentially, which implies the need for tight regulation mechanisms to maintain cell size throughout growth and division cycles. Here, we characterize the growth behavior of the apically growing bacterium Corynebacterium glutamicum, by developing a novel and broadly applicable inference method for single-cell growth dynamics. We find that this bacterium grows asymptotically linearly, enabling it to maintain a narrow distribution of cell sizes, despite having a large variability of single-cell growth features. Our results imply a novel interplay between mode of growth and division regulation mechanisms, which may extend to other bacteria with non-exponential growth modes.

scholarly journals The Ethanologenic Bacterium Zymomonas mobilis Divides Asymmetrically and Exhibits Heterogeneity in DNA Content

2021 ◽  
Vol 87 (6) ◽  
Author(s):  
Katsuya Fuchino ◽  
Helena Chan ◽  
Ling Chin Hwang ◽  
Per Bruheim
Keyword(s):  
Cell Growth ◽  
Single Cell ◽  
Cell Size ◽  
Dna Content ◽  
Bacterial Cell ◽  
Zymomonas Mobilis ◽  
Biofuel Production ◽  
Public Attention ◽  
Content Type ◽  
Cell Organization

ABSTRACT The alphaproteobacterium Zymomonas mobilis exhibits extreme ethanologenic physiology, making this species a promising biofuel producer. Numerous studies have investigated its biology relevant to industrial applications and mostly at the population level. However, the organization of single cells in this industrially important polyploid species has been largely uncharacterized. In the present study, we characterized basic cellular behavior of Z. mobilis strain Zm6 under anaerobic conditions at the single-cell level. We observed that growing Z. mobilis cells often divided at a nonmidcell position, which contributed to variant cell size at birth. However, the cell size variance was regulated by a modulation of cell cycle span, mediated by a correlation of bacterial tubulin homologue FtsZ ring accumulation with cell growth. The Z. mobilis culture also exhibited heterogeneous cellular DNA content among individual cells, which might have been caused by asynchronous replication of chromosome that was not coordinated with cell growth. Furthermore, slightly angled divisions might have resulted in temporary curvatures of attached Z. mobilis cells. Overall, the present study uncovers a novel bacterial cell organization in Z. mobilis. IMPORTANCE With increasing environmental concerns about the use of fossil fuels, development of a sustainable biofuel production platform has been attracting significant public attention. Ethanologenic Z. mobilis species are endowed with an efficient ethanol fermentation capacity that surpasses, in several respects, that of baker’s yeast (Saccharomyces cerevisiae), the most-used microorganism for ethanol production. For development of a Z. mobilis culture-based biorefinery, an investigation of its uncharacterized cell biology is important, because bacterial cellular organization and metabolism are closely associated with each other in a single cell compartment. In addition, the current work demonstrates that the polyploid bacterium Z. mobilis exhibits a distinctive mode of bacterial cell organization, likely reflecting its unique metabolism that does not prioritize incorporation of nutrients for cell growth. Thus, another significant result of this work is to advance our general understanding in the diversity of bacterial cell architecture.

scholarly journals Effect of Laser Irradiation on Cell Function and Its Implications in Raman Spectroscopy

2018 ◽  
Vol 84 (8) ◽  
pp. e02508-17 ◽  
Author(s):  
Xiaofei Yuan ◽  
Yanqing Song ◽  
Yizhi Song ◽  
Jiabao Xu ◽  
Yinhu Wu ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Cell Growth ◽  
Single Cell ◽  
Laser Irradiation ◽  
Living Cells ◽  
Growth Characteristics ◽  
Single Cell Level ◽  
Bacterial Cells ◽  
Cell Level ◽  
Gram Negative

ABSTRACTLasers are instrumental in advanced bioimaging and Raman spectroscopy. However, they are also well known for their destructive effects on living organisms, leading to concerns about the adverse effects of laser technologies. To implement Raman spectroscopy for cell analysis and manipulation, such as Raman-activated cell sorting, it is crucial to identify nondestructive conditions for living cells. Here, we evaluated quantitatively the effect of 532-nm laser irradiation on bacterial cell fate and growth at the single-cell level. Using a purpose-built microfluidic platform, we were able to quantify the growth characteristics, i.e., specific growth rates and lag times of individual cells, as well as the survival rate of a population in conjunction with Raman spectroscopy. Representative Gram-negative and Gram-positive species show similar trends in response to a laser irradiation dose. Laser irradiation could compromise the physiological function of cells, and the degree of destruction is both dose and strain dependent, ranging from reduced cell growth to a complete loss of cell metabolic activity and finally to physical disintegration. Gram-positive bacterial cells are more susceptible than Gram-negative bacterial strains to irradiation-induced damage. By directly correlating Raman acquisition with single-cell growth characteristics, we provide evidence of nondestructive characteristics of Raman spectroscopy on individual bacterial cells. However, while strong Raman signals can be obtained without causing cell death, the variety of responses from different strains and from individual cells justifies careful evaluation of Raman acquisition conditions if cell viability is critical.IMPORTANCEIn Raman spectroscopy, the use of powerful monochromatic light in laser-based systems facilitates the detection of inherently weak signals. This allows environmentally and clinically relevant microorganisms to be measured at the single-cell level. The significance of being able to perform Raman measurement is that, unlike label-based fluorescence techniques, it provides a “fingerprint” that is specific to the identity and state of any (unlabeled) sample. Thus, it has emerged as a powerful method for studying living cells under physiological and environmental conditions. However, the laser's high power also has the potential to kill bacteria, which leads to concerns. The research presented here is a quantitative evaluation that provides a generic platform and methodology to evaluate the effects of laser irradiation on individual bacterial cells. Furthermore, it illustrates this by determining the conditions required to nondestructively measure the spectra of representative bacteria from several different groups.

scholarly journals Osmolyte homeostasis controls single-cell growth rate and maximum cell size of Saccharomyces cerevisiae

2019 ◽  
Vol 5 (1) ◽  
Author(s):  
Tom Altenburg ◽  
Björn Goldenbogen ◽  
Jannis Uhlendorf ◽  
Edda Klipp
Keyword(s):  
Growth Rate ◽  
Cell Wall ◽  
Cell Growth ◽  
Single Cell ◽  
Cell Size ◽  
Single Cells ◽  
Turgor Pressure ◽  
Thermodynamic Quantities ◽  
Cell Growth Rate ◽  
Final Size

Abstract Cell growth is well described at the population level, but precisely how nutrient and water uptake and cell wall expansion drive the growth of single cells is poorly understood. Supported by measurements of single-cell growth trajectories and cell wall elasticity, we present a single-cell growth model for yeast. The model links the thermodynamic quantities, such as turgor pressure, osmolarity, cell wall elasto-plasticity, and cell size, applying concepts from rheology and thin shell theory. It reproduces cell size dynamics during single-cell growth, budding, and hyper-osmotic or hypo-osmotic stress. We find that single-cell growth rate and final size are primarily governed by osmolyte uptake and consumption, while bud expansion requires additionally different cell wall extensibilities between mother and bud. Based on first principles the model provides a more accurate description of size dynamics than previous attempts and its analytical simplification allows for easy combination with models for other cell processes.

Single‐cell growth behavior of Corynebacterium glutamicum under pH oscillations

2020 ◽  
Vol 92 (9) ◽  
pp. 1238-1238
Author(s):  
S. Täuber ◽  
L. Blöbaum ◽  
A. Grünberger
Keyword(s):  
Cell Growth ◽  
Single Cell ◽  
Corynebacterium Glutamicum ◽  
Growth Behavior

scholarly journals Osmolyte homeostasis controls single-cell growth rate and maximum cell size ofSaccharomyces cerevisiae

2019 ◽  
Author(s):  
Tom Altenburg ◽  
Björn Goldenbogen ◽  
Jannis Uhlendorf ◽  
Edda Klipp
Keyword(s):  
Growth Rate ◽  
Cell Wall ◽  
Cell Growth ◽  
Single Cell ◽  
Cell Size ◽  
Single Cells ◽  
Turgor Pressure ◽  
Thermodynamic Quantities ◽  
Cell Growth Rate ◽  
Final Size

Cell growth is well described at the population level, but precisely how nutrient and water uptake and cell wall expansion drive the growth of single cells is poorly understood. Supported by measurements of single-cell growth trajectories and cell wall elasticity, we present a single-cell growth model for yeast. The model links the thermodynamic quantities turgor pressure, osmolarity, cell wall elasto-plasticity, and cell size, using concepts from rheology and thin shell theory. It reproduces cell size dynamics during single-cell growth, budding, and hyper- or hypoosmotic stress. We find that single-cell growth rate and final size are primarily governed by osmolyte uptake and consumption, while bud expansion depends additionally on different cell wall extensibilities of mother and bud. Based on first principles the model provides a more accurate description of size dynamics than previous attempts and its analytical simplification allows for easy combination with models for other cell processes.

scholarly journals cgCorrect: A method to correct for confounding cell-cell variation due to cell growth in single-cell transcriptomics

2016 ◽  
Author(s):  
Thomas Blasi ◽  
Florian Buettner ◽  
Michael K. Strasser ◽  
Carsten Marr ◽  
Fabian J. Theis
Keyword(s):  
Gene Expression ◽  
Steady State ◽  
Cell Growth ◽  
Single Cell ◽  
Cell Size ◽  
Computational Analysis ◽  
Simulated Data ◽  
Supplementary Information ◽  
Mrna Transcript ◽  
Transcriptomics Data

AbstractMotivation: Accessing gene expression at the single cell level has unraveled often large heterogeneity among seemingly homogeneous cells, which remained obscured in traditional population based approaches. The computational analysis of single-cell transcriptomics data, however, still imposes unresolved challenges with respect to normalization, visualization and modeling the data. One such issue are differences in cell size, which introduce additional variability into the data, for which appropriate normalization techniques are needed. Otherwise, these differences in cell size may obscure genuine heterogeneities among cell populations and lead to overdispersed steady-state distributions of mRNA transcript numbers.Results: We present cgCorrect, a statistical framework to correct for differences in cell size that are due to cell growth in single-cell transcriptomics data. We derive the probability for the cell growth corrected mRNA transcript number given the measured, cell size dependent mRNA transcript number, based on the assumption that the average number of transcripts in a cell increases proportional to the cell’s volume during cell cycle. cgCorrect can be used for both data normalization, and to analyze steady-state distributions used to infer the gene expression mechanism. We demonstrate its applicability on both simulated data and single-cell quantitative real-time PCR data from mouse blood stem and progenitor cells. We show that correcting for differences in cell size affects the interpretation of the data obtained by typically performed computational analysis.Availability: A Matlab implementation of cgCorrect is available at http://icb.helmholtz-muenchen.de/cgCorrectSupplementary information: Supplementary information are available online. The simulated data set is available at http://icb.helmholtz-muenchen.de/cgCorrect

scholarly journals Biphasic growth dynamics duringCaulobacter crescentusdivision

2016 ◽  
Author(s):  
Shiladitya Banerjee ◽  
Klevin Lo ◽  
Matthew K. Daddysman ◽  
Alan Selewa ◽  
Thomas Kuntz ◽  
...  
Keyword(s):  
Cell Growth ◽  
Cell Size ◽  
Caulobacter Crescentus ◽  
Growth Dynamics ◽  
Size Control ◽  
Biphasic Model ◽  
A Cell ◽  
Cell Cycle Dependence ◽  
Cycle Dependence ◽  
Shape Data

Cell size is specific to each species and impacts their ability to function. While various phenomenological models for cell size regulation have been proposed, recent work in bacteria have demonstrated anaddermodel, in which a cell increments its size by a constant amount between each division. However, the coupling between cell size, shape and constriction, remain poorly understood. Here, we investigate size control and the cell cycle dependence of bacterial growth, using multigenerational cell growth and shape data for singleCaulobacter crescentuscells. Our analysis reveals a biphasic mode of growth:a relative timerphase before constriction where cell growth is correlated to its initial size, followed by apure adderphase during constriction. Cell wall labeling measurements reinforce this biphasic model: a crossover from uniform lateral growth to localized septal growth is observed. We present a mathematical model that quantitatively explains this biphasicmixermodel for cell size control.

scholarly journals Cell biological studies of ethanologenic bacterium Zymomonas mobilis

2020 ◽  
Author(s):  
Katsuya Fuchino ◽  
Helena Chan ◽  
Ling Chin Hwang ◽  
Per Bruheim
Keyword(s):  
Cell Growth ◽  
Single Cell ◽  
Cell Size ◽  
Bacterial Cell ◽  
Zymomonas Mobilis ◽  
Single Cells ◽  
Biofuel Production ◽  
Public Attention ◽  
Biological Studies ◽  
Cell Organization

AbstractAlphaproteobacterium Zymomonas mobilis exhibits extreme ethanologenic physiology, making this species a promising biofuel producer. Numerous studies have investigated its biology relevant to industrial applications and mostly at the population level. However, the organization of single cells in this industrially important, polyploid species has been largely uncharacterized.In the present study, we characterized basic cellular behaviour of Z. mobilis strain Zm6 at a single cell level. We observed that growing Z. mobilis cells often divided at non mid-cell position, which contributed to variant cell size at birth. Yet, the cell size variance was regulated by a modulation of cell cycle span, mediated by a correlation of bacterial tubulin homologue FtsZ-ring accumulation with cell growth. The Z. mobilis culture also exhibited heterogeneous cellular DNA contents among individual cells, which might have been caused by asynchronous replication of chromosome that was not coordinated to cell growth. Furthermore, slightly angled divisions might have rendered temporary curvatures of attached Z. mobilis cells. Overall, the presented study uncovered a novel bacterial cell organization in Z. mobilis, the metabolism of which is not favoured for biosynthesis to build biomass.ImportanceWith increasing environmental concerns about the exhausting use of fossil fuels, a development of sustainable biofuel production platform has been attracting significant public attention. Ethanologenic Z. mobilis species are endowed with an efficient ethanol-fermentation capacity that surpass, in several aspects, that of the baker’s yeast Saccharomyces cerevisiae, the most used microorganism for ethanol productions. For a development of Z. mobilis culture-based biorefinery, an investigation of its uncharacterized cell biology is important, because bacterial cellular organization and metabolism are closely associated with each other in a single cell compartment.In addition, the current work highlights that polyploid bacterium Z. mobilis exhibits a distinctive mode of bacterial cell organization, reflecting its unique metabolism that do not prioritize incorporation of nutrients to cell growth. Thus, another significance of presented work is to advance our general understanding in the diversity of bacterial cell architecture.

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