Faculty Opinions recommendation of Cellular locomotion using environmental topography.

2020 ◽  
Author(s):  
Keng-hui Lin
Keyword(s):  
Cellular Locomotion

scholarly journals Cellular locomotion using environmental topography

Nature ◽  
2020 ◽  
Vol 582 (7813) ◽  
pp. 582-585 ◽  
Author(s):  
Anne Reversat ◽  
Florian Gaertner ◽  
Jack Merrin ◽  
Julian Stopp ◽  
Saren Tasciyan ◽  
...  
Keyword(s):  
Cellular Locomotion

Indications of Spontaneous Chaos in the Chemotaxis of E. coli under Noise-Induced Parametric Perturbations

2015 ◽  
Vol 4 (1) ◽  
pp. 52-65
Author(s):  
Pratap R. Patnaik
Keyword(s):  
Cell Walls ◽  
Fractal Dimensions ◽  
Recent Analysis ◽  
Time Intervals ◽  
E Coli ◽  
Marginal Effects ◽  
Intense Noise ◽  
Key Variables ◽  
Chemical Stimuli ◽  
Cellular Locomotion

Bacteria such as Escherichia coli navigating through real environments in response to chemical stimuli are under the continual influence of perturbations (or ‘noise') from within the cells, at the interface between the cell walls and the chemical ligands, and from the extra-cellular surroundings. These perturbations interact with one another and affect the chemosensory reactions that determine the movements of a population of cells. A recent analysis has shown that the response coefficients of certain key variables describing the chemotaxis of E. coli can vary by several orders of magnitude when the kinetic parameters are disturbed by noise-induced fluctuations, thereby inducing corresponding variations in cellular locomotion. This possibility is explored quantitatively here by using the same mathematical model as in the earlier work. The model considers the cells to be in one of three states: some cells moving toward the chemoattractant, some moving away and others in an intermediate ‘tumbling' state. The focus was on the tumbling cells since they are the most sensitive to disturbances. Based on previous work, the fractal dimensions of the cells tracked over a length of time were used as indicators of stable or unstable chemotaxis. Results showed that while noise-induced variations in some parameters had only marginal effects on cell motility, other parameters strongly influenced the population movement. In the latter cases the chemically guided movement of the population toward the chemoattractant could, under sufficiently intense noise, become chaotic in certain intervals of time. Significantly, the time intervals for such spontaneous chaos differed from one parameter to another, being contiguous with one another, rather than overlapping. Thus at any point in time there is the likelihood of chaotic instability caused by one or more of the parameters, thereby destabilizing the population as a whole. These observations underscore (a) the importance of analyzing the effects of noise on bacterial chemosensory kinetics, (b) limiting the intensity of noise permeating the cells, and (c) the usefulness of fractal dimensions in aiding such analysis.

Release from Density-Dependent Inhibition of Growth in the Absence of Cell Locomotion

1974 ◽  
Vol 16 (1) ◽  
pp. 181-188
Author(s):  
MARGARET M. YARNELL ◽  
H. P. SCHNEBLI
Keyword(s):  
Insulin Treatment ◽  
Density Dependent ◽  
Mouse Fibroblasts ◽  
Cell Locomotion ◽  
Inhibition Of Growth ◽  
Dependent Inhibition ◽  
Cellular Locomotion

3T3 mouse fibroblasts are released from density-dependent inhibition of growth by treatment with insulin. The same insulin treatment stimulates cell locomotion several hours before any new mitoses become visible. Inhibition of cell locomotion by colcemid does not affect the overgrowth stimulation due to insulin. From this it is concluded that cellular locomotion is not a prerequisite for the release from density-dependent inhibition of growth.

scholarly journals The kinetics of chemotactic peptide-induced change in F-actin content, F-actin distribution, and the shape of neutrophils.

1985 ◽  
Vol 101 (3) ◽  
pp. 1078-1085 ◽  
Author(s):  
T H Howard ◽  
C O Oresajo
Keyword(s):  
Cell Shape ◽  
Actin Polymerization ◽  
Time Course ◽  
Control Level ◽  
Actin Depolymerization ◽  
Cell Biol ◽  
Rate Of Polymerization ◽  
Resultant Increase ◽  
Cellular Locomotion ◽  
Cell Changes

Formyl-met-leu-phe (fMLP) induces actin assembly in neutrophils; the resultant increase in F-actin content correlates with an increase in the rate of cellular locomotion at fMLP concentrations less than or equal to 10(-8) M (Howard, T.H., and W.H. Meyer, 1984, J. Cell Biol., 98:1265-1271). We studied the time course of change in F-actin content, F-actin distribution, and cell shape after fMLP stimulation. F-actin content was quantified by fluorescence activated cell sorter analysis of nitrobenzoxadiazole-phallacidin-stained cells (Howard, T.H., 1982, J. Cell Biol., 95(2, Pt. 2:327a). F-actin distribution and cell shape were determined by analysis of fluorescence photomicrographs of nitrobenzoxadiazole-phallacidin-stained cells. After fMLP stimulation at 25 degrees C, there is a rapid actin polymerization that is maximal (up to 2.0 times the control level) at 45 s; subsequently, the F-actin depolymerizes to an intermediate F-actin content 5-10 min after stimulation. The depolymerization of F-actin reflects a true decrease in F-actin content since the quantity of probe extractable from cells also decreases between 45 s and 10 min. The rate of actin polymerization (3.8 +/- 0.3-4.4 +/- 0.6% increase in F-actin/s) is the same for 10(-10) - 10(-6) M fMLP and the polymerization is inhibited by cytochalasin D. The initial rate of F-actin depolymerization (6.0 +/- 1.0-30 +/- 5% decrease in F-actin/min) is inversely proportional to fMLP dose. The F-actin content of stimulated cells at 45 s and 10 min is greater than control levels and varies directly with fMLP dose. F-actin distribution and cell shape also vary as a function of time after stimulation. 45 s after stimulation the cells are rounded and F-actin is diffusely distributed; 10 min after stimulation the cell is polarized and F-actin is focally distributed. These results indicate that actin polymerization and depolymerization follow fMLP stimulation in sequence, the rate of depolymerization and the maximum and steady state F-actin content but not the rate of polymerization are fMLP dose dependent, and concurrent with F-actin depolymerization, F-actin is redistributed and the cell changes shape.

scholarly journals FACTORS AFFECTING THE REDISTRIBUTION OF SURFACE-BOUND CONCANAVALIN A ON HUMAN POLYMORPHONUCLEAR LEUKOCYTES

1974 ◽  
Vol 62 (2) ◽  
pp. 351-365 ◽  
Author(s):  
Graeme B. Ryan ◽  
Joan Z. Borysenko ◽  
Morris J. Karnovsky
Keyword(s):  
Concanavalin A ◽  
Polymorphonuclear Leukocytes ◽  
Cytochalasin B ◽  
Immobilized Cells ◽  
Fluorescein Isothiocyanate ◽  
Cross Linking ◽  
Con A ◽  
Factors Affecting ◽  
Motile Cells ◽  
Cellular Locomotion

Human neutrophil polymorphonuclear leukocytes (PMN) were studied to determine the influence of cellular locomotion upon the redistribution and capping of concanavalin A (Con A). Con A was detected by fluorescence (using Con A conjugated to fluorescein isothiocyanate [Con A-FITC]), or on shadow-cast replicas (using Busycon canaliculatum hemocyanin as a marker for Con A). After labeling with Con A 100 µg/ml at 4°C and warming to 37°C, locomotion occurred, and the Con A quickly aggregated into a cap at the trailing end of the cell. When locomotion was inhibited (with cytochalasin B, or by incubation in serum-free medium at 18°C) Con A rapidly formed a cap over the central region of the cell. Iodoacetamide inhibited capping. PMN labeled with FITC, a monovalent ligand, developed caps at the tail only on motile cells; FITC remained dispersed on immobilized cells. PMN exposed to Con A 100 µg/ml at 37°C bound more lectin than at 4°C, became immobilized, and showed slow central capping. The Con A soon became internalized to form a perinuclear ring. Such treatment in the presence of cytochalasin B resulted in the quick formation of persistent central caps. Colchicine (or prior cooling) protected PMN from the immobilizing effect of Con A, and tail caps were found on 30–40% of cells. Immobilization of colchicine-treated cells caused Con A to remain in dispersed clusters. Thus, capping on PMN is a temperature- and energy-dependent process that proceeds independently of cellular locomotion, provided a colchicine-sensitive system is intact and the ligand is capable of cross linking receptors. On the other hand, if the cell does move, it appears that ligands may be swept into a cap at the tail whether cross-linking occurs or not.

scholarly journals Automated cell tracking using StarDist and TrackMate

2020 ◽  
Author(s):  
Elnaz Fazeli ◽  
Nathan H. Roy ◽  
Gautier Follain ◽  
Romain F. Laine ◽  
Lucas von Chamier ◽  
...  
Keyword(s):  
Open Source Software ◽  
Large Scale ◽  
Cell Tracking ◽  
Quantitative Imaging ◽  
Immune Surveillance ◽  
Supplementary Information ◽  
Large Scale Analysis ◽  
Deep Learning Network ◽  
Cellular Locomotion ◽  
Automatically Tracking

The ability of cells to migrate is a fundamental physiological process involved in embryonic development, tissue homeostasis, immune surveillance, and wound healing. Therefore, the mechanisms governing cellular locomotion have been under intense scrutiny over the last 50 years. One of the main tools of this scrutiny is live-cell quantitative imaging, where researchers image cells over time to study their migration and quantitatively analyze their dynamics by tracking them using the recorded images. Despite the availability of computational tools, manual tracking remains widely used among researchers due to the difficulty setting up robust automated cell tracking and large-scale analysis. Here we provide a detailed analysis pipeline illustrating how the deep learning network StarDist can be combined with the popular tracking software TrackMate to perform 2D automated cell tracking and provide fully quantitative readouts. Our proposed protocol is compatible with both fluorescent and widefield images. It only requires freely available and open-source software (ZeroCostDL4Mic and Fiji), and does not require any coding knowledge from the users, making it a versatile and powerful tool for the field. We demonstrate this pipeline’s usability by automatically tracking cancer cells and T cells using fluorescent and brightfield images. Importantly, we provide, as supplementary information, a detailed step-by-step protocol to allow researchers to implement it with their images.

scholarly journals A Mathematical Model for Cellular Locomotion Exhibiting Chemotaxis

2001 ◽  
Vol 3 (2) ◽  
pp. 101-123 ◽  
Author(s):  
M. J. Holmes ◽  
B. D. Sleeman
Keyword(s):  
Fundamental Problem ◽  
Cellular Biology ◽  
Thin Sheets ◽  
Dimensional Model ◽  
Key Factors ◽  
Forward Motion ◽  
Amoeboid Motion ◽  
Cellular Locomotion ◽  
Chemotactic Behaviour ◽  
Cellular Motion

A fundamental problem of cellular biology is to understand the mechanisms underlying cellular locomotion. Bacterial organisms may use appendages such as flagellae or cilia to facilitate motion. Amoeboid motion [6], exhibited by eucaryotic cells are seen to flatten onto surfaces and extend thin sheets of cytosol called lamellipodia. These in turn make attachments to the surface and by the initiation of internal contractions within the cell, a forward motion is achieved. The processes which govern this behaviour are extremely complex, however, key ingredients have been identified which may provide a sufficient basis for persistent cellular motion. These factors are osmotichydrostatic expansion and cellular contraction mediated by intracellular calcium ca2+. In this paper, we develop a simple two dimensional model for a non-muscle motile cell based on these two key factors. We show it is capable of producing persistent cellular motion and chemotactic behaviour.

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