Chemotaxis in the Green Flagellate Alga Chlamydomonas

Govorunova, Elena G.; Sineshchekov, Oleg A.

doi:10.1007/s10541-005-0176-2

Cited by 31 publications

(26 citation statements)

References 71 publications

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“…Although swimming is widespread among phytoplankton (Horner et al 1997), its ecological importance has typically been considered primarily in relation to photic migration (Kamykowski et al 1998), physical stratification (Erga et al 2003), or sex (Govoronova and Sineshchekov 2005). Our observations indicate that phytoplankton motility and chemotaxis can significantly increase exposure to nutrient patches, imparting a considerable nutrient advantage to chemotactic cells.…”

Section: Exploitation Of Nutrient Patches By Phytoplanktonmentioning

confidence: 83%

Resource Patch Formation and Exploitation throughout the Marine Microbial Food Web

Seymour¹,

Marcos²,

Stocker³

2009

The American Naturalist

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Section: Exploitation Of Nutrient Patches By Phytoplanktonmentioning

confidence: 83%

Resource Patch Formation and Exploitation throughout the Marine Microbial Food Web

Seymour¹,

Marcos²,

Stocker³

2009

The American Naturalist

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“…Considering algal sensory physiology and TRP1's permeability and voltage dependence, it is not unreasonable to speculate that TRP1 channels might function downstream of the sensory input generation (e.g., light-induced Channelrhodopsin activation), contributing to the regeneration of the resting potential after sensory-dependent depolarization. An association between photosensory and chemosensory pathways has been suggested in the past (Govorunova and Sineshchekov, 2005), and there is experimental evidence supporting the idea that the potassium conductance linking these pathways may (A) Instantaneous current protocol for TRP1 (top left). The cell was exposed to a +160-mV depolarizing potential pulse and then pulsed to voltages between 2160 and +160 mV in 20-mV increments (bottom left).…”

Section: Discussionmentioning

confidence: 97%

A Transient Receptor Potential Ion Channel in Chlamydomonas Shares Key Features with Sensory Transduction-Associated TRP Channels in Mammals

et al. 2015

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Sensory modalities are essential for navigating through an ever-changing environment. From insects to mammals, transient receptor potential (TRP) channels are known mediators for cellular sensing. Chlamydomonas reinhardtii is a motile single-celled freshwater green alga that is guided by photosensory, mechanosensory, and chemosensory cues. In this type of alga, sensory input is first detected by membrane receptors located in the cell body and then transduced to the beating cilia by membrane depolarization. Although TRP channels seem to be absent in plants, C. reinhardtii possesses genomic sequences encoding TRP proteins. Here, we describe the cloning and characterization of a C. reinhardtii version of a TRP channel sharing key features present in mammalian TRP channels associated with sensory transduction. In silico sequence-structure analysis unveiled the modular design of TRP channels, and electrophysiological experiments conducted on Human Embryonic Kidney-293T cells expressing the Cr-TRP1 clone showed that many of the core functional features of metazoan TRP channels are present in Cr-TRP1, suggesting that basic TRP channel gating characteristics evolved early in the history of eukaryotes.

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“…For Chlamydomonas U ∼ 50-200 μm·s −1 (10,12) and R ∼ 5 μm. As a green alga, Chlamydomonas feeds on inorganic ions (18) but has also demonstrated chemotaxis toward larger organic biomolecules, e.g., maltose and sucrose (19). Considering that Chlamydomonas can be found in its natural habitat near freezing temperatures, the nutrient diffusivities range from D ∼ 10 −10 to 10 −9 m 2 :s −1 and hence the Péclet number Pe U varies between ∼0.1 and 10.…”

Section: A-dmentioning

confidence: 99%

Optimal feeding and swimming gaits of biflagellated organisms

Tam

Hosoi

2011

Proc. Natl. Acad. Sci. U.S.A.

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Locomotion is widely observed in life at micrometric scales and is exhibited by many eukaryotic unicellular organisms. Motility of such organisms can be achieved through periodic deformations of a tail-like projection called the eukaryotic flagellum. Although the mechanism allowing the flagellum to deform is largely understood, questions related to the functional significance of the observed beating patterns remain unresolved. Here, we focus our attention on the stroke patterns of biflagellated phytoplanktons resembling the green alga Chlamydomonas. Such organisms have been widely observed to beat their flagella in two different ways-a breaststroke and an undulatory stroke-both of which are prototypical of general beating patterns observed in eukaryotes. We develop a general optimization procedure to determine the existence of optimal swimming gaits and investigate their functional significance with respect to locomotion and nutrient uptake. Both the undulatory and the breaststroke represent local optima for efficient swimming. With respect to the generation of feeding currents, we found the breaststroke to be optimal and to enhance nutrient uptake significantly, particularly when the organism is immersed in a gradient of nutrients.optimization | stroke kinematics | low Reynolds number | efficiency T he vast majority of living organisms are found in an astonishing diversity at micrometric scales. Such seemingly simple unicellular organisms interact with their surroundings and exhibit complex dynamic behaviors in order to access resource-rich environments. The ability to locate and take advantage of such favorable environments relies on a rapid chemotactic response (1, 2). In this paper, we investigate the motility of specific microorganisms to address questions related to the functional adaptation, efficiency, and optimization of biolocomotion.A dominant trait shared by many microorganisms is the prevalence of flagella as motility appendages. The structure of the axoneme, which constitutes the core of the eukaryotic flagellum, is extremely well preserved across the eukaryotic domain. This same structure is found to propel sperm cells and, when several of them beat collectively as cilia, to expel mucus from human lungs. The eukaryotic flagellum has a complex internal "9 þ 2" microtubule structure (3), whose elaborate molecular machinery allows the flagellum to induce local bending moments and actively deform its shape. It is noteworthy that these flagella are widely observed to beat in two significantly different ways: undulatory traveling waves that propagate down the flagellum (as exhibited by sperm cells), and so-called "effective recovery" strokes commonly observed in cilia. Because it is possible for organisms to alter and control the waveform along the flagellum, it is of interest to investigate the functional significance of these specific flagellar stroke patterns and their utility with respect to swimming and feeding.Previous investigations of nutrient transport and hydrodynamics around microorganisms (4...

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Chemotaxis in the Green Flagellate Alga Chlamydomonas

Cited by 31 publications

References 71 publications

Resource Patch Formation and Exploitation throughout the Marine Microbial Food Web

Resource Patch Formation and Exploitation throughout the Marine Microbial Food Web

A Transient Receptor Potential Ion Channel in Chlamydomonas Shares Key Features with Sensory Transduction-Associated TRP Channels in Mammals

Optimal feeding and swimming gaits of biflagellated organisms

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