细胞技术

Chemotaxis is a highly coordinated biological system where chemoattractants trigger multiple signal transduction pathways which act in concert to bring about directed migration. A signaling pathway acting through PIP3, which accumulates at the leading edge of the cell, has been ex ...

During development a variety of cell types are guided by molecular concentration gradients to form tissues and organ systems. In the nervous system, the migration and neuronal pathfinding that occurs during development is organized and driven by “guidance cues.” Some of these cues are subs ...

We describe an in vivo invasion assay that enables the collection of invasive cells from the primary tumor. In addition to determination of the endogenous, unstimulated invasive properties of cells in vivo, the assay can take advantage of the chemotactic properties of cancer cells. Microne ...

Cell motility is a widely researched and clinically relevant process that has primarily been investigated using cell culture models. While these in vitro assays are useful in allowing for high-resolution analysis of cell movement, there will always be questions surrounding the physi ...

Correct distal tip cell (DTC) migration in the nematode C. elegans requires sensing soluble and matrix cues, remodeling extracellular matrix, and signaling through conserved integrin and netrin pathways. The DTC executes a complex path and coordinates its migration with the develop ...

The ability of cells to migrate directionally in gradients of chemoattractant is a fundamental biological response that is essential for the survival of the social amoebae Dictyostelium discoideum. In Dictyostelium, cAMP is the most potent chemoattractant and the detection, synt ...

Virtually all eukaryotic cells can grow in a polarized fashion in response to external signals. Cells can respond to gradients of chemoattractants or chemorepellents by directional growth, a process referred to as chemotropism. The budding yeast Saccharomyces cerevisiae underg ...

Electric fields were measured at human skin wounds over one and half centuries ago. Modern techniques have verified and greatly extended our understanding of the existence of endogenous wound electric fields. In virtually all wounds studied, disruption of an epithelial layer instant ...

Dictyostelium slugs are able to respond to environmental stimuli in an extremely sensitive and efficient way. This enables a slug to migrate to more favourable locations for formation of fruiting bodies and dispersal of spores. Phototaxis is a readily assayed phenotype and reflects the in ...

Motile microorganisms react to a host of external stimuli, including light, gravity, the magnetic field of the Earth as well as thermal and chemical gradients, in their habitat in order to select a niche suitable for survival and reproduction. Several forms of light-induced behavior have been d ...

The task of developing and simulating computational models of signaling networks for eukaryotic chemosensing confronts the modeler with several challenges: (1) The stimuli that initiate the cellular responses one wishes to study are provided by extracellular concentration gr ...

When stimulated by chemoattractants, eukaryotic cells respond through a combination of temporal and spatial dynamics. These responses come about because of the interaction of a large number of signaling components. The complexity of these systems makes it hard to understand without a ...

Many eukaryotic cells move in the direction of a chemical gradient. Several assays have been developed to measure this chemotactic response, but no complete mathematical models of the spatial and temporal gradients are available to describe the fundamental principles of chemotaxis. ...

For decades, Dictyostelium discoideum has been an efficacious and attractive model system for the study of cell motility, primarily because cells become highly motile during the transition from growth phase to aggregation competence and because the haploid genome is readily amenab ...

Microorganisms have various mechanisms at their disposal to react to (changes in) their ambient light climate (i.e., intensity, color, direction, and degree of polarization). Of these, one of the best studied mechanisms is the process of phototaxis. This process can be described as a behavior ...

B-cell activation initiates antibody responses against pathogens. Recent imaging of B cells in vivo shows that B cells move rapidly through lymphoid tissues to search for antigens captured on the surfaces of antigen-presenting cells. Recognition of antigens by the B-cell antigen rece ...

In this chapter, we describe methods to monitor signaling events at the single-molecule level on the membrane of living cells by using total internal reflection fluorescence microscopy (TIRFM). The techniques provide a powerful tool for elucidating the stochastic properties of sign ...

Since directed movement toward an extracellular chemoattractant requires rapid and continuous reorgani�zation of the actin cytoskeleton to form complex structures such as a protruding lamellipodium, it is of great interest to analyze and understand the individual contribut ...

This chapter will focus on responses that the chemoattractant cyclic AMP elicits in the motility system of Dictyostelium. These cells can be permanently transfected to express cytoskeleton-associated proteins tagged with fluorescent proteins. Multiple proteins that are dis ...

How a eukaryotic cell translates a small concentration difference of a chemoattractant across the length of its surface into highly polarized intracellular responses is a fundamental question in chemotaxis. Chemoattractants are detected by G-protein-coupled receptors (GP ...