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Quantification of Live Bacterial Sensing for Chemotaxis and Phagocytosis and of Macropinocytosis

Initial immunological defense mechanisms to pathogen invasion rely on innate pathways of chemotaxis and phagocytosis, original to ancient phagocytes. Although chemotaxis has been well-studied in mammalian and model systems using purified chemoattractants in defined conditions, directed movement towa...

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Autores principales: Meena, Netra P., Kimmel, Alan R.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Frontiers Media S.A. 2018
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5840232/
https://www.ncbi.nlm.nih.gov/pubmed/29552545
http://dx.doi.org/10.3389/fcimb.2018.00062
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author Meena, Netra P.
Kimmel, Alan R.
author_facet Meena, Netra P.
Kimmel, Alan R.
author_sort Meena, Netra P.
collection PubMed
description Initial immunological defense mechanisms to pathogen invasion rely on innate pathways of chemotaxis and phagocytosis, original to ancient phagocytes. Although chemotaxis has been well-studied in mammalian and model systems using purified chemoattractants in defined conditions, directed movement toward live bacteria has been more difficult to assess. Dictyostelium discoideum is a professional phagocyte that chemotaxes toward bacteria during growth-phase in a process to locate nutrient sources. Using Dictyostelium as a model, we have developed a system that is able to quantify chemotaxis to very high sensitivity. Here, Dictyostelium can detect various chemoattractants at concentrations <1 nM. Given this exceedingly sensitive signal response, Dictyostelium will migrate directionally toward live gram positive and gram negative bacteria, in a highly quantifiable manner, and dependent upon bacterially-secreted chemoattractants. Additionally, we have developed a real-time, quantitative assay for phagocytosis of live gram positive and gram negative bacteria. To extend the analyses of endocytic functions, we further modified the system to quantify cellular uptake via macropinocytosis of smaller (<100 kDa) molecules. These various approaches provide novel means to dissect potential for identification of novel chemoattractants and mechanistic factors that are essential for chemotaxis, phagocytosis, and/or macropinocytosis and for more detailed understanding in host-pathogen interactive defenses.
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spelling pubmed-58402322018-03-16 Quantification of Live Bacterial Sensing for Chemotaxis and Phagocytosis and of Macropinocytosis Meena, Netra P. Kimmel, Alan R. Front Cell Infect Microbiol Microbiology Initial immunological defense mechanisms to pathogen invasion rely on innate pathways of chemotaxis and phagocytosis, original to ancient phagocytes. Although chemotaxis has been well-studied in mammalian and model systems using purified chemoattractants in defined conditions, directed movement toward live bacteria has been more difficult to assess. Dictyostelium discoideum is a professional phagocyte that chemotaxes toward bacteria during growth-phase in a process to locate nutrient sources. Using Dictyostelium as a model, we have developed a system that is able to quantify chemotaxis to very high sensitivity. Here, Dictyostelium can detect various chemoattractants at concentrations <1 nM. Given this exceedingly sensitive signal response, Dictyostelium will migrate directionally toward live gram positive and gram negative bacteria, in a highly quantifiable manner, and dependent upon bacterially-secreted chemoattractants. Additionally, we have developed a real-time, quantitative assay for phagocytosis of live gram positive and gram negative bacteria. To extend the analyses of endocytic functions, we further modified the system to quantify cellular uptake via macropinocytosis of smaller (<100 kDa) molecules. These various approaches provide novel means to dissect potential for identification of novel chemoattractants and mechanistic factors that are essential for chemotaxis, phagocytosis, and/or macropinocytosis and for more detailed understanding in host-pathogen interactive defenses. Frontiers Media S.A. 2018-03-02 /pmc/articles/PMC5840232/ /pubmed/29552545 http://dx.doi.org/10.3389/fcimb.2018.00062 Text en Copyright © 2018 Meena and Kimmel. http://creativecommons.org/licenses/by/4.0/ This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
spellingShingle Microbiology
Meena, Netra P.
Kimmel, Alan R.
Quantification of Live Bacterial Sensing for Chemotaxis and Phagocytosis and of Macropinocytosis
title Quantification of Live Bacterial Sensing for Chemotaxis and Phagocytosis and of Macropinocytosis
title_full Quantification of Live Bacterial Sensing for Chemotaxis and Phagocytosis and of Macropinocytosis
title_fullStr Quantification of Live Bacterial Sensing for Chemotaxis and Phagocytosis and of Macropinocytosis
title_full_unstemmed Quantification of Live Bacterial Sensing for Chemotaxis and Phagocytosis and of Macropinocytosis
title_short Quantification of Live Bacterial Sensing for Chemotaxis and Phagocytosis and of Macropinocytosis
title_sort quantification of live bacterial sensing for chemotaxis and phagocytosis and of macropinocytosis
topic Microbiology
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5840232/
https://www.ncbi.nlm.nih.gov/pubmed/29552545
http://dx.doi.org/10.3389/fcimb.2018.00062
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