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Chemotaxis - Wikipedia, the free encyclopedia Chemotaxis is a kind of taxis, in which bodily cells, bacteria, and other single-cell or multicellular organisms direct their movements according to certain chemicals in their environment. Chemotaxis is called positive, if the movement is in the direction of the higher concentration of the chemical in question and negative, if the direction is opposite. Chemotaxis has high significance in the early phases of embryogenesis as development of germ layers is guided by gradients of signal molecules. en.wikipedia.org /wiki/Chemotaxis   (2413 words)

Chemotaxis   (Site not responding. Last check: 2007-11-02) The term "Chemotaxis" was first coined by a W. Pfeffer in 1884 to describe the attraction of fern sperm to the ova, but since then the phenomenon has been described in bacteria and many eukaryotic cells in many different situations. Chemotaxis helps the sperm find the egg in humans (Eisenbach and Tur-Kaspa, 1994), and in algae where a chemo-attractant increases the turning angle of the sperm cell so that it spirals in toward the egg like a captured moon. From the top, chemotaxis requires the chemotactic receptor, heterotrimeric G-proteins, Whereas the distribution of chemotactic receptors is uniform across the cell (Xiao et al, 1997), other signalling molecules further down the cascade are found to have a polarized distribution. www.bms.ed.ac.uk /research/others/smaciver/Chemotaxis.htm   (1443 words)

[No title]   (Site not responding. Last check: 2007-11-02) Chemotaxis is the ability of bacteria, other organisms, or single cells of multicellular organisms to direct their movements according to certain chemicals in their environment. This is important for bacteria to find food (for example, glucose) by swimming towards the highest concentration of food molecules, or to flee from poisons (for example, phenole). Chemotaxis steers the bacterium by regulating the tumbling frequency and duration (?). www.wikiwhat.com /encyclopedia/c/ch/chemotaxis.html   (372 words)

Chemotaxis and flagellar genes of Chromobacterium violaceum A close examination of the chemoreceptors methyl-accepting chemotaxis proteins (MCPs), and the deduced sequences of the members of the two-component signaling system revealed canonical motifs, described as essential for the function of the deduced proteins. In the chemotaxis network, the receptor and kinase functions are separated in order to allow the cell to execute an integrated response to multiple stimuli (Tsang et al., 1973). Chemotaxis begins with the binding of molecules to four kinds of receptors in the plasma membrane. funpecrp.com.br /GMR/year2004/vol1-3/SCv0007_full_text.htm   (2306 words)

Continuous-Flow Capillary Assay for Measuring Bacterial Chemotaxis -- Law and Aitken 71 (6): 3137 -- Applied and ... with the wild-type strain was caused by chemotaxis to naphthalene. Chemotaxis to plant phenolic inducers of virulence genes is constitutively expressed in the absence of the Ti-plasmid in Agrobacterium tumefaciens. Quantitation of the sensory response in bacterial chemotaxis. aem.asm.org /cgi/content/full/71/6/3137   (4304 words)

Bacterial Chemotaxis toward Environmental Pollutants: Role in Bioremediation -- Pandey and Jain 68 (12): 5789 -- ... Chemotaxis and degradation of 3-methyl-4-nitrophenol by Ralstonia sp. Identification of a pcaRKF gene cluster from Pseudomonas putida: involvement in chemotaxis, biodegradation, and transport of 4-hydroxybenzoate. Cloning and characterization of chemotaxis genes in Pseudomonas aeruginosa. aem.asm.org /cgi/content/full/68/12/5789   (3448 words)

Chemotaxis - Wikipedia Chemotaxis bezeichnet die Beeinflussung der Ortsbewegung von Lebewesen oder Zellen von Lebewesen durch Stoffkonzentrationsgradienten. Bakterien sind durch Chemotaxis in der Lage, Orte mit optimaler Konzentration eines Nährstoffs oder von Sauerstoff aufzusuchen und Orte mit schädlichen Stoffen zu meiden. Chemotaxis ist Voraussetzung für ein funktionierendes Immunsystem und Blutsystem. de.wikipedia.org /wiki/Chemotaxis   (307 words)

Millipore - Technical Library - Chemotaxis and Angiogenesis Assays in a 96-well Format for Use in High-Throughput Drug ... Chemotaxis, in response to NIH3T3 fibroblast conditioned medium or serum-containing medium as chemoattractants, was assessed for 4-5 h on 3 and 5 µm membrane pore size MIC plates. Chemotaxis of (A) highly migratory MDAMB231 cells and (B) nonmigratory MCF7 cells in response to 10% serum-containing medium as a chemoattractant. Chemotaxis in response to 10% serum-containing medium as a chemoattractant in the presence of inhibitors at indicated concentrations. www.millipore.com /publications.nsf/docs/5MBJLK   (1551 words)

CHEMOTAXIS Chemotaxis — the response of cells to chemical stimuli by directed movement — is one of the most basic and fascinating processes in nature, involved in both health and disease. The authors demonstrate how basic chemotaxis is to life and how widespread it is, and presents the state of the art with respect to its molecular and physiological mechanisms. Because chemotaxis research is still in progress, the book also indicates open questions and future directions of research. www.worldscibooks.com /lifesci/p303.html   (280 words)

Definition of Chemotaxis Chemotaxis is the phenomenon in which bacteria, other organisms, or single cells of multicellular organisms direct their movements according to certain chemicals in their environment. Chemotaxis steers the bacterium by regulating the tumbling frequency and duration. Unlike motility in bacterial chemotaxis, the mechanism by which eukaryotic cells physcially move is unclear. www.wordiq.com /definition/Chemotaxis   (794 words)

CHEMOTAXIS-GUIDED MOVEMENTS IN BACTERIA -- Lux and Shi 15 (4): 207 -- Critical Reviews in Oral Biology & Medicine Membrane receptors for aspartate and serine in bacterial chemotaxis. Role of chemotaxis in the association of motile bacteria with intestinal mucosa: chemotactic responses of Vibrio cholerae and description of motile nonchemotactic mutants. Molecular characterization of a chemotaxis operon in the oral spirochete, Treponema denticola. crobm.iadrjournals.org /cgi/content/full/15/4/207   (6511 words)

Chemotaxis   (Site not responding. Last check: 2007-11-02) The action of a compound on cells is often the subject of study. Chemotaxis is the study of the attraction or repulsion of cells by compounds. The behaviour of cells in response to chemicals can be technically difficult and can be helped by the use of containers with filter components that can be inserted into the normally used growth chambers. www.nuncbrand.com /page/en/317.aspx   (87 words)

Chicken Soup Inhibits Neutrophil Chemotaxis In Vitro -- Rennard et al. 118 (4): 1150 -- Chest ZAS (dilution, 1:4) and chicken soup (cs) (prep 1, fraction 18 diluted 1:100) were added to the top and bottom of the chemotaxis chamber in various combinations as indicated. Chemotaxis then was measured using ZAS diluted 1:4 as the chemoattractant. Harvath, L, Falk, W, Leonard, EJ (1980) Rapid quantitation of neutrophil chemotaxis: use of a polyvinylpyrrolidone-free polycarbonate membrane in a multiwell assembly. www.chestjournal.org /cgi/content/full/118/4/1150   (3358 words)

Human Neutrophil Chemotaxis Is Modulated by Capsule and O Antigen from an Extraintestinal Pathogenic Escherichia coli ... Neutrophil chemotaxis toward cell-free culture supernatants was primarily N-t-BOC sensitive (100, 97.4, and 96% for CP9, CP921, and CP9.137, respectively); therefore, N-t-BOC-insensitive chemotaxis toward cell-free culture supernatants is not shown. Neutrophil chemotaxis was similar (not less) in response to the mixtures of supernatants from CP9 plus CP921 and CP9 plus CP9.137 compared to when the chemotactic activity due to supernatant from CP9 and CP921 alone and CP9 and CP9.137 alone was averaged (ave.) (n = 2). to N-t-BOC-sensitive neutrophil chemotaxis in vivo is unclear. iai.asm.org /cgi/content/full/71/11/6435   (6587 words)

LDL Stimulates Chemotaxis of Human Monocytes Through a Cyclooxygenase-Dependent Pathway -- Kreuzer et al. 16 (12): 1481 ... Chemotaxis is expressed as percent of migration of control cells cultivated in medium with 10% FCS. Restoration of chemotaxis by LDL after cultivation of cells in medium with 10% FCS or 10% LPDS was abolished through inhibition of lysosomal degradation of LDL and inhibition of cyclooxygenase. Rapid quantitation of neutrophile chemotaxis: use of a polyvinylpyrolidone-free polycarbonate membrane in a multiwell assembly. atvb.ahajournals.org /cgi/content/full/16/12/1481   (4073 words)

BioMed Central | Full text | Metallothionein mediates leukocyte chemotaxis This assay employs a miniature under-agarose chemotaxis chamber in which cell arrival on a surface microelectrode is measured by changes to electrical current flow through the electrode [21]. Another common aspect of chemotactic signaling is an activation of the actin polymerization machinery in response to a sharp increase in chemoattractant concentration [26,55]. In addition to the general increase in resistance caused by cells covering the electrode, rapid fluctuations in resistance are indicative of changes in the shape and surface adherence of cells, and of continuing cell viability and movement. www.biomedcentral.com /1471-2172/6/21   (5972 words)

Towards Understanding the Molecular Mechanism of Sperm Chemotaxis -- Eisenbach 124 (2): 105 -- The Journal of General ... Chemotaxis of capacitated rabbit spermatozoa to follicular fluid revealed by a novel directionality-based assay. Suzuki, N. Structure, function and biosynthesis of sperm-activating peptides and fucose sulfate glycoconjugate in the extracellular coat of sea urchin eggs. Chemotaxis of Arbacia punctulata spermatozoa to resact, a peptide from the egg jelly layer. www.jgp.org /cgi/content/full/124/2/105   (1974 words)

Step-Response Analysis of Chemotaxis in Caenorhabditis elegans -- Miller et al. 25 (13): 3369 -- Journal of Neuroscience The chemotaxis behavior of the nematode Caenorhabditis elegans Chemotaxis was quantified in terms of an index I that reflected Ward S (1973) Chemotaxis by the nematode Caenorhabditis elegans: identification of attractants and analysis of the response by use of mutants. www.jneurosci.org /cgi/content/full/25/13/3369   (7241 words)

Modification of PI3K- and MAPK-Dependent Chemotaxis in Aortic Vascular Smooth Muscle Cells by Protein Kinase C{beta}II ...   (Site not responding. Last check: 2007-11-02) Chemotaxis to PDGF-BB (360 pmol/L), absent in 5 In conclusion, chemotaxis to PDGF-BB in 25 mmol/L glucose is Glucose-potentiated chemotaxis in human vascular smooth muscle is dependent on cross-talk between the PI3K and MAPK signaling pathways. circres.ahajournals.org /cgi/content/full/96/2/197   (4116 words)

Chemotaxis   (Site not responding. Last check: 2007-11-02) Role in cell chemotaxis and cell activation, Journal of Neuroimmunology 90(1) :21, 1998. Cytokine-stimulated chemotaxis of human neutrophils in a 3-D conjoined fibrin gel assay. PKC and tyrosine kinase involvement in amyloid beta (25-35)-induced chemotaxis of microglia, Neuroreport 9(15) :3467-3470, 1998. www.math.ubc.ca /~ais/website/refs/chemo.html   (247 words)

Chemicon - Product #ECM512 - QCM™ Chemotaxis 96 well (5 μM) Cell Migration Assay, Fluorimetric; 0.3 cm(2), ... The quantitative nature of this assay is especially useful for large scale screening of pharmacological agents. The system may be adapted to study different types of cell migration, including haptotaxis, random migration, chemokinesis, and chemotaxis. The Chemicon QCM™ 5 μm 96-well Migration Assay provides a quick and efficient system for quantitative determination of various factors on cell migration, including screening of pharmacological agents, evaluation of integrins or other adhesion receptors responsible for cell migration, or analysis of gene function in transfected cells. www.chemicon.com /browse/productdetail.asp?ProductID=ECM512   (1002 words)

Chemotaxis You can view chemotaxis in a 560K Movie. A longer, larger, silent version of this clip is available as a download for use in class projects or demonstrations. Chemotaxis is part of the "Immune System Collection". www.cellsalive.com /chemotx.htm   (134 words)

Different Evolutionary Constraints on Chemotaxis Proteins CheW and CheY Revealed by Heterologous Expression Studies and ... binding to a chemoreceptor in vitro and chemotaxis in vivo. The two-component signaling pathway of bacterial chemotaxis: a molecular view of signal transduction by receptors, kinases, and adaptation enzymes. Role of the CheW protein in bacterial chemotaxis: overexpression is equivalent to absence. jb.asm.org /cgi/content/full/185/2/544   (4476 words)

Chemotaxis - Voyager, the free encyclopedia   (Site not responding. Last check: 2007-11-02) Chemotaxis is the phenomenon in which bodily cells, bacteria, and other single-celled or multicellular organisms direct their movements according to certain chemicals in their environment. Counter-clockwise rotation aligns the flagella into a single rotating bundle, causing the bacterium to swim in a straight line. There appears to be mechanisms by which an external chemotactic gradient is sensed and turned into an intracellular PIP2 gradient, which results in a gradient in the activation of signalling pathway culminating in the polymerisation of actin filaments, although the details of the signalling pathway is still not totally clear. www.voyager.in /Chemotaxis   (928 words)

Characterization of a Novel Methyl-Accepting Chemotaxis Gene, dmcB, from the Oral Spirochete Treponema denticola -- Li ... Characterization of a Novel Methyl-Accepting Chemotaxis Gene, dmcB, from the Oral Spirochete Treponema denticola -- Li et al. Spirochete chemotaxis, motility, and the structure of the spirochetal periplasmic flagella. Characterization of a methyl-accepting chemotaxis protein gene, dmcA, from the oral spirochete Treponema denticola. iai.asm.org /cgi/content/full/67/2/694   (3159 words)

2005 GRC on Gradient Sensing & Directed Cell Migration Because chemotaxis is critical for development (especially in neurobiology), immunology, wound healing, and tumor cell metastasis, the meeting is designed to bring together the leading chemotaxis researchers in these fields for cross-fertilization of concepts and approaches. This strategy is manifested by organizing each topic according to stage in the signal processing pathway; for example, researchers in different fields who are focused chemotaxis receptors are grouped together in a single session. The session topics are chosen to focus attention on the critical steps in chemotactic signaling, providing attendees with an integrated overview of the entire chemotaxis process over the course of the entire meeting. www.grc.uri.edu /programs/2005/gradient.htm   (406 words)

Lockery Lab Research Computations performed by the nervous system during chemotaxis are further evaluated by delivering controlled chemical stimulations to freely moving worms, and record their behaviors. Individual neurons in the chemotaxis network are killed with a laser microbeam to identify their role in chemotaxis behavior, thereby defining a neuronal circuit. In order to understand how the behavioral strategy for chemotaxis is implemented by the worm's nervous system, data generated by the experimental approaches are synthesized in theoretical models of the chemotaxis network. chinook.uoregon.edu /research.html   (687 words)

A Role for Cdc42 in Macrophage Chemotaxis -- Allen et al. 141 (5): 1147 -- The Journal of Cell Biology Chemotaxis was assessed by direct observation and recording of cell behavior in stable concentration gradients of CSF-1 using Involvement of phosphatidylinositide 3'-kinase and Rac in platelet-derived growth factor-induced actin reorganization and chemotaxis. Cell polarity: an examination of its behavioral expression and its consequences for polymorphonuclear leukocyte chemotaxis. www.jcb.org /cgi/content/full/141/5/1147   (7208 words)

Galpha i Is Not Required for Chemotaxis Mediated by Gi-coupled Receptors -- Neptune et al. 274 (5): 2824 -- Journal of ... Galpha i Is Not Required for Chemotaxis Mediated by Gi-coupled Receptors -- Neptune et al. Assays-- Assays of chemotaxis, cAMP accumulation, and inositol phosphate accumulation were performed as described (9). with and activation of a hypothetical downstream effector of chemotaxis. www.jbc.org /cgi/content/full/274/5/2824   (3417 words)

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