Cell Signaling Among Bacteria (Campbell Biology)
Scientists think that signaling mechanisms first evolved in ancient prokaryotes and single-celled eukaryotes like yeasts and then were adopted for new uses by their multicellular descendants. Cell signaling is also critical among prokaryotes. For example, bacterial cells secrete molecules that can be detected by other bacterial cells. Sensing the concentration of such signaling molecules allows bacteria to monitor their own local cell density, a phenomenon called quorum sensing. Quorum sensing allows bacterial populations to coordinate their behaviors in activities that require a given number of cells acting synchronously. One example is formation of a biofilm, an aggregation of bacterial cells adhered to a surface. The cells in the biofilm often derive nutrition from the surface they are on. You have probably encountered biofilms many times, perhaps without realizing it. The slimy coating on a fallen log or on leaves lying on a forest path, and even the film on your teeth each morning, are examples of bacterial biofilms. In fact, toothbrushing and flossing disrupt biofilms that would otherwise cause cavities and gum disease.– What is the ability to detect and to respond to cell population density by gene regulation?
Soil-dwelling bacteria called myxobacteria (“slime bacteria”) use chemical signals to share information about nutrient availability. When food is scarce, starving cells secrete a signaling molecule that stimulates neighboring cells to aggregate. The cells form a structure called a fruiting body that produces spores, thick-walled cells capable of surviving until the environment improves. The myxobacteria shown in the picture are the species Myxococcus xanthus.– What bacteria aggregate into fruiting bodies, a process long-thought to be mediated by chemotaxis but now considered to be a function of a form of contact-mediated signaling?
Urry, Lisa A.. Campbell Biology. Pearson Education. Kindle Edition. https://www.pearson.com/us/higher-education/series/Campbell-Biology-Series/2244849.html
Date Published: December 5, 2013 Publisher: Public Library of Science Author(s): Matthias Jeschke, Stephan Baumgärtner, Stefan Legewie, Jason M. Haugh Abstract: Cells reliably sense environmental changes despite internal and external fluctuations, but the mechanisms underlying robustness remain unclear. We analyzed how fluctuations in signaling protein concentrations give rise to cell-to-cell variability in protein kinase signaling … Continue reading
Date Published: May 7, 2015 Publisher: Public Library of Science Author(s): Jianfeng Xu, Yueheng Lan, Ying Xu. http://doi.org/10.1371/journal.pone.0125886 Abstract: Despite much effort, identification of modular structures and study of their organizing and functional roles remain a formidable challenge in molecular systems biology, which, however, is essential in reaching a systematic understanding of large-scale cell regulation … Continue reading
Research Article: Cell Membrane Disruption Stimulates NO/PKG Signaling and Potentiates Cell Membrane Repair in Neighboring Cells
Date Published: August 7, 2012 Publisher: Public Library of Science Author(s): Tatsuru Togo, Paul McNeil. http://doi.org/10.1371/journal.pone.0042885 Abstract: Resealing of a disrupted plasma membrane at the micron-diameter range requires Ca2+-regulated exocytosis. Repeated membrane disruptions reseal more quickly than the initial wound, and this potentiation of membrane resealing persists for at least 24 hours after the initial wound. … Continue reading
Research Article: Cell-to-Cell Signaling Influences the Fate of Prostate Cancer Stem Cells and Their Potential to Generate More Aggressive Tumors
Date Published: February 6, 2012 Publisher: Public Library of Science Author(s): Luisa Salvatori, Francesca Caporuscio, Alessandra Verdina, Giuseppe Starace, Stefania Crispi, Maria Rita Nicotra, Andrea Russo, Raffaele Adolfo Calogero, Emanuela Morgante, Pier Giorgio Natali, Matteo Antonio Russo, Elisa Petrangeli, Alfredo Fusco. http://doi.org/10.1371/journal.pone.0031467 Abstract: An increasing number of malignancies has been shown to be initiated and propelled … Continue reading