Torus generated by Escherichia coli

Šimkus, Remigijus; Kirejev, V.; Meškienė, Rita; Meškys, Rolandas

doi:10.1007/s00348-008-0598-x

Cited by 13 publications

(29 citation statements)

References 18 publications

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“…It has been recently shown that bioluminescence imaging can be employed to validate mathematical models of bacterial self‐organization. In particular, the abovementioned merging–emerging patterns were, to the best of our knowledge, for the first time observed experimentally in cylindrical samples of liquid cultures of bioluminescent Escherichia coli . The imagining showed luminous aggregates of bacteria merging and emerging along the three‐phase contact lines.…”

Section: Introductionmentioning

confidence: 55%

“…The cultures were prepared as described previously . In particular, as a reporter bacterium we use a genetically engineered strain of E .…”

Section: Methodsmentioning

confidence: 99%

“…Optical density measurements at 600 nm (OD 600 ) were used to monitor the concentration of cells. The freshly harvested mid‐log phase cultures (OD 600 = 0.4), corresponding to the cell density of ~1.08 × 10 8 cells/mL were chosen for examination . The induction of the culture was provided by adding a stock solution IPTG into LB medium up to the final concentration of 1 mM.…”

Section: Methodsmentioning

confidence: 99%

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Microtiter plate tests for segregation of bioluminescent bacteria

et al. 2015

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It has been recently shown that bioluminescence imaging can be usefully applied to provide new insights into bacterial self-organization. In this work we employ bioluminescence imaging to record images of nutrient rich liquid cultures of the lux-gene reporter Escherichia coli in microtiter plate wells. The images show that patterns of inhomogenous bioluminescence form along the three-phase contact lines. The paper analyzes the dependencies of the average number of luminous aggregates (clouds) on various environmental factors. In particular, our results show that optimal (neutral) pH and high aeration rates determine the highest mean number of clouds, and that spatiotemporal patterns do not form in the pH buffered suspensions. In addition, a sigmoidal (switch-like) dependence of the number of aggregates on the rate of aeration was observed. The obtained bioluminescence imaging data was interpreted by employing the Keller-Segel-Fisher (KSF) model of chemotaxis and logistic growth, adapted to systems of metabolically flexible (two-state) bacteria. The modified KSF model successfully simulated the observed switch-like responses. The results of the microtiter plate tests and their simulations indicate that the segregation of bacteria with different activities proceeds in the three-phase contact line region.

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Section: Introductionmentioning

confidence: 55%

“…The cultures were prepared as described previously . In particular, as a reporter bacterium we use a genetically engineered strain of E .…”

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

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Microtiter plate tests for segregation of bioluminescent bacteria

et al. 2015

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“…. A semi‐qualitative description of the observed azimuthal wave patterns and illustrative frames taken from a time series were given in our previous report . These turbulent ‘flame’ structures can be seen as a vortex ring together with an array of hairpin‐shaped vortices.…”

Section: Resultsmentioning

confidence: 99%

“…This phenomenon was called oscillatory bioluminescence. Recently, we have observed the corresponding spatiotemporal patterns of bioluminescence in the liquid cultures of lux gene engineered Escherichia coli by employing bioluminescence imaging technique (18). Inhomogeneous bacterial bioluminescence was also observed in liquid cultures of Todarodes pacificus ((19) and references therein).…”

Section: Introductionmentioning

confidence: 98%

Metabolic self‐organization of bioluminescent Escherichia coli

Šimkus

Baronas

2011

Luminescence

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A possible reason for the complexity of the signals produced by bioluminescent biosensors might be self-organization of the cells. In order to verify this possibility, bioluminescence images of cultures of lux gene reporter Escherichia coli were recorded for several hours after being placed into 8-10 mm diameter cylindrical containers. It was found that luminous cells distribute near the three-phase contact line, forming irregular azimuthal waves. As we show, space-time plots of quasi-one-dimensional bioluminescence measured along the contact line can be simulated by reaction-diffusion-chemotaxis equations, in which the reaction term for the cells is a logistic (autocatalytic) growth function. It was found that the growth rate of the luminous cells (~0.02 s(-1)) is >100 times higher than the growth rate of E. coli. We provide an explanation for this result by assuming that E. coli exhibits considerable respiratory flexibility (the ability of oxygen-induced switching from one metabolic pathway to another). According to the simple two-state model presented here, the number of oxic (luminous) cells grows at the expense of anoxic (dark) cells, whereas the total number of (oxic and anoxic) cells remains unchanged. It is conjectured that the corresponding reaction-diffusion-chemotaxis model for bioluminescence pattern formation can be considered as a model for the energy-taxis and metabolic self-organization in the population of the metabolically flexible bacteria under hypoxic conditions.

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