@article{AlirezaeizanjaniGrossmannPfeiferetal.2020,
  author    = {Alirezaeizanjani, Zahra and Großmann, Robert and Pfeifer, Veronika and Hintsche, Marius and Beta, Carsten},
  title     = {Chemotaxis strategies of bacteria with multiple run modes},
  series = {Science advances},
  volume    = {6},
  journal   = {Science advances},
  number    = {22},
  publisher = {American Association for the Advancement of Science},
  address   = {Washington},
  issn      = {2375-2548},
  doi       = {10.1126/sciadv.aaz6153},
  pages     = {8},
  year      = {2020},
  abstract  = {Bacterial chemotaxis-a fundamental example of directional navigation in the living world-is key to many biological processes, including the spreading of bacterial infections. Many bacterial species were recently reported to exhibit several distinct swimming modes-the flagella may, for example, push the cell body or wrap around it. How do the different run modes shape the chemotaxis strategy of a multimode swimmer? Here, we investigate chemotactic motion of the soil bacterium Pseudomonas putida as a model organism. By simultaneously tracking the position of the cell body and the configuration of its flagella, we demonstrate that individual run modes show different chemotactic responses in nutrition gradients and, thus, constitute distinct behavioral states. On the basis of an active particle model, we demonstrate that switching between multiple run states that differ in their speed and responsiveness provides the basis for robust and efficient chemotaxis in complex natural habitats.},
  language  = {en}
}
@article{SeyrichAlirezaeizanjaniBetaetal.2018,
  author    = {Seyrich, Maximilian and Alirezaeizanjani, Zahra and Beta, Carsten and Stark, Holger},
  title     = {Statistical parameter inference of bacterial swimming strategies},
  series = {New journal of physics : the open-access journal for physics},
  volume    = {20},
  journal   = {New journal of physics : the open-access journal for physics},
  publisher = {IOP Publ. Ltd.},
  address   = {Bristol},
  issn      = {1367-2630},
  doi       = {10.1088/1367-2630/aae72c},
  pages     = {20},
  year      = {2018},
  abstract  = {We provide a detailed stochastic description of the swimming motion of an E. coli bacterium in two dimension, where we resolve tumble events in time. For this purpose, we set up two Langevin equations for the orientation angle and speed dynamics. Calculating moments, distribution and autocorrelation functions from both Langevin equations and matching them to the same quantities determined from data recorded in experiments, we infer the swimming parameters of E. coli. They are the tumble rate lambda, the tumble time r(-1), the swimming speed v(0), the strength of speed fluctuations sigma, the relative height of speed jumps eta, the thermal value for the rotational diffusion coefficient D-0, and the enhanced rotational diffusivity during tumbling D-T. Conditioning the observables on the swimming direction relative to the gradient of a chemoattractant, we infer the chemotaxis strategies of E. coli. We confirm the classical strategy of a lower tumble rate for swimming up the gradient but also a smaller mean tumble angle (angle bias). The latter is realized by shorter tumbles as well as a slower diffusive reorientation. We also find that speed fluctuations are increased by about 30\% when swimming up the gradient compared to the reversed direction.},
  language  = {en}
}
@misc{AlirezaeizanjaniWaljorHintscheetal.2017,
  author    = {Alirezaeizanjani, Zahra and Waljor, V. and Hintsche, Marius and Beta, Carsten},
  title     = {How growth conditions affect bacterial chemotaxis responses},
  series = {European biophysics journal : with biophysics letters ; an international journal of biophysics},
  volume    = {46},
  journal   = {European biophysics journal : with biophysics letters ; an international journal of biophysics},
  publisher = {Springer},
  address   = {New York},
  issn      = {0175-7571},
  pages     = {S281 -- S281},
  year      = {2017},
  language  = {en}
}
@article{WeberBahrsAlirezaeizanjanietal.2019,
  author    = {Weber, Ariane and Bahrs, Marco and Alirezaeizanjani, Zahra and Zhang, Xingyu and Beta, Carsten and Zaburdaev, Vasily},
  title     = {Rectification of Bacterial Diffusion in Microfluidic Labyrinths},
  series = {Frontiers in Physics},
  volume    = {7},
  journal   = {Frontiers in Physics},
  publisher = {Frontiers Media},
  address   = {Lausanne},
  issn      = {2296-424X},
  doi       = {10.3389/fphy.2019.00148},
  pages     = {11},
  year      = {2019},
  abstract  = {In nature as well as in the context of infection and medical applications, bacteria often have to move in highly complex environments such as soil or tissues. Previous studies have shown that bacteria strongly interact with their surroundings and are often guided by confinements. Here, we investigate theoretically how the dispersal of swimming bacteria can be augmented by microfluidic environments and validate our theoretical predictions experimentally. We consider a system of bacteria performing the prototypical run-and-tumble motion inside a labyrinth with square lattice geometry. Narrow channels between the square obstacles limit the possibility of bacteria to reorient during tumbling events to an area where channels cross. Thus, by varying the geometry of the lattice it might be possible to control the dispersal of cells. We present a theoretical model quantifying diffusive spreading of a run-and-tumble random walker in a square lattice. Numerical simulations validate our theoretical predictions for the dependence of the diffusion coefficient on the lattice geometry. We show that bacteria moving in square labyrinths exhibit enhanced dispersal as compared to unconfined cells. Importantly, confinement significantly extends the duration of the phase with strongly non-Gaussian diffusion, when the geometry of channels is imprinted in the density profiles of spreading cells. Finally, in good agreement with our theoretical findings, we observe the predicted behaviors in experiments with E. coli bacteria swimming in a square lattice labyrinth created in amicrofluidic device. Altogether, our comprehensive understanding of bacterial dispersal in a simple two-dimensional labyrinth makes the first step toward the analysis of more complex geometries relevant for real world applications.},
  language  = {en}
}