| 1. |
- Zaburdaev, Vasily, et al.
(författare)
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Uncovering the Mechanism of Trapping and Cell Orientation during Neisseria gonorrhoeae Twitching Motility
- 2014
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Ingår i: Biophysical Journal. - : Elsevier BV. - 0006-3495 .- 1542-0086. ; 107:7, s. 1523-1531
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Tidskriftsartikel (refereegranskat)abstract
- Neisseria gonorrheae bacteria are the causative agent of the second most common sexually transmitted infection in the world. The bacteria move on a surface by means of twitching motility. Their movement is mediated by multiple long and flexible filaments, called type IV pili, that extend from the cell body, attach to the surface, and retract, thus generating a pulling force. Moving cells also use pili to aggregate and form microcolonies. However, the mechanism by which the pili surrounding the cell body work together to propel bacteria remains unclear. Understanding this process will help describe the motility of N. gonorrheae bacteria, and thus the dissemination of the disease which they cause. In this article we track individual twitching cells and observe that their trajectories consist of alternating moving and pausing intervals, while the cell body is preferably oriented with its wide side toward the direction of motion. Based on these data, we propose a model for the collective pili operation of N. gonorrheae bacteria that explains the experimentally observed behavior. Individual pili function independently but can lead to coordinated motion or pausing via the force balance. The geometry of the cell defines its orientation during motion. We show that by changing pili substrate interactions, the motility pattern can be altered in a predictable way. Although the model proposed is tangibly simple, it still has sufficient robustness to incorporate further advanced pili features and various cell geometries to describe other bacteria that employ pili to move on surfaces.
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| 2. |
- Monzo, Pascale, et al.
(författare)
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Adaptive mechanoproperties mediated by the formin FMN1 characterize glioblastoma fitness for invasion
- 2021
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Ingår i: Developmental Cell. - : Elsevier. - 1534-5807 .- 1878-1551. ; 56:20, s. 2841-2855.e8
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Tidskriftsartikel (refereegranskat)abstract
- Glioblastoma are heterogeneous tumors composed of highly invasive and highly proliferative clones, Heterogeneity in invasiveness could emerge from discrete biophysical properties linked to specific molecular expression. We identified clones of patient-derived glioma propagating cells that were either highly proliferative or highly invasive and compared their cellular architecture, migratory, and biophysical properties. We discovered that invasiveness was linked to cellular fitness. The most invasive cells were stiffer, developed higher mechanical forces on the substrate, and moved stochastically. The mechano-chemical-induced expression of the formin FMN1 conferred invasive strength that was confirmed in patient samples. Moreover, FMN1 expression was also linked to motility in other cancer and normal cell lines, and its ectopic expression increased fitness parameters. Mechanistically, FMN1 acts from the microtubule lattice and promotes a robust mechanical cohesion, leading to highly invasive motility.
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