000212517 001__ 212517
000212517 005__ 20181203024021.0
000212517 0247_ $$2doi$$a10.1073/pnas.1422922112
000212517 022__ $$a0027-8424
000212517 02470 $$2ISI$$a000355832200073
000212517 037__ $$aARTICLE
000212517 245__ $$aGeneralized receptor law governs phototaxis in the phytoplankton Euglena gracilis
000212517 260__ $$aWashington$$bNatl Acad Sciences$$c2015
000212517 269__ $$a2015
000212517 300__ $$a6
000212517 336__ $$aJournal Articles
000212517 520__ $$aPhototaxis, the process through which motile organisms direct their swimming toward or away from light, is implicated in key ecological phenomena (including algal blooms and diel vertical migration) that shape the distribution, diversity, and productivity of phytoplankton and thus energy transfer to higher trophic levels in aquatic ecosystems. Phototaxis also finds important applications in biofuel reactors and microbiopropellers and is argued to serve as a benchmark for the study of biological invasions in heterogeneous environments owing to the ease of generating stochastic light fields. Despite its ecological and technological relevance, an experimentally tested, general theoretical model of phototaxis seems unavailable to date. Here, we present accurate measurements of the behavior of the alga Euglena gracilis when exposed to controlled light fields. Analysis of E. gracilis' phototactic accumulation dynamics over a broad range of light intensities proves that the classic Keller-Segel mathematical framework for taxis provides an accurate description of both positive and negative phototaxis only when phototactic sensitivity is modeled by a generalized "receptor law," a specific nonlinear response function to light intensity that drives algae toward beneficial light conditions and away from harmful ones. The proposed phototactic model captures the temporal dynamics of both cells' accumulation toward light sources and their dispersion upon light cessation. The model could thus be of use in integrating models of vertical phytoplankton migrations inmarine and freshwater ecosystems, and in the design of bioreactors.
000212517 6531_ $$aphototactic potential
000212517 6531_ $$aphotoresponse
000212517 6531_ $$asensory system
000212517 6531_ $$aphotoaccumulation
000212517 6531_ $$amicrobial motility
000212517 700__ $$0245835$$aGiometto, Andrea$$g217715$$uEcole Polytech Fed Lausanne, Sch Architecture Civil & Environm Engn, Lab Ecohydrol, CH-1015 Lausanne, Switzerland
000212517 700__ $$aAltermatt, Florian$$uEawag Swiss Fed Inst Aquat Sci & Technol, Dept Aquat Ecol, CH-8600 Dubendorf, Switzerland
000212517 700__ $$aMaritan, Amos$$uUniv Padua, Dipartimento Fis & Astron, I-35131 Padua, Italy
000212517 700__ $$aStocker, Roman$$uMIT, Dept Civil & Environm Engn, Ralph M Parsons Lab, Cambridge, MA 02139 USA
000212517 700__ $$0240022$$aRinaldo, Andrea$$g182281$$uEcole Polytech Fed Lausanne, Sch Architecture Civil & Environm Engn, Lab Ecohydrol, CH-1015 Lausanne, Switzerland
000212517 773__ $$j112$$k22$$q7045-7050$$tProceedings Of The National Academy Of Sciences Of The United States Of America
000212517 909C0 $$0252014$$pECHO$$xU10273
000212517 909CO $$ooai:infoscience.tind.io:212517$$particle$$pENAC
000212517 917Z8 $$x106284
000212517 937__ $$aEPFL-ARTICLE-212517
000212517 973__ $$aEPFL$$rREVIEWED$$sPUBLISHED
000212517 980__ $$aARTICLE