Chemosensory behaviour of <i>Tetrahymena</i>

and, Vegn Leick And; Hellung‐Larsen, Per

doi:10.1002/bies.950140113

Cited by 30 publications

(10 citation statements)

References 24 publications

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“…There appear to be molecular interactions between protozoa and bacteria which may employ dissolved cues for chemical-mediated prey selection. Chemicals involved in chemosensory attraction could include proteins, amino acids, and other dissolved inorganic or organic nutrients[19, 20]. Other prey metabolites may prevent grazing, including pyrrolnitrin, 2, 4-diacetylphloroglucinol, hydrogen cyanide, and pyoluteorin[21, 22].…”

Section: Introductionmentioning

confidence: 99%

The dialogue between protozoa and bacteria in a microfluidic device

Gaines

Ludovice

et al. 2019

PLoS ONE

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In nature, protozoa play a major role in controlling bacterial populations. This paper proposes a microfluidic device for the study of protozoa behaviors change due to their chemotactic response in the presence of bacterial cells. A three-channel microfluidic device was designed using a nitrocellulose membrane into which channels were cut using a laser cutter. The membrane was sandwiched between two glass slides; a Euglena suspension was then allowed to flow through the central channel. The two side channels were filled with either, 0.1% peptone as a negative control, or a Listeria suspension respectively. The membrane design prevented direct interaction but allowed Euglena cells to detect Listeria cells as secretions diffused through the nitrocellulose membrane. A significant number of Euglena cells migrated toward the chambers near the bacterial cells, indicating a positive chemotactic response of Euglena toward chemical cues released from Listeria cells. Filtrates collected from Listeria suspension with a series of molecular weight cutoffs (3k, 10k and 100k) were examined in Euglena chemotaxis tests. Euglena cells were attracted to all filtrates collected from the membrane filtration with different molecular weight cutoffs, suggesting small molecules from Listeria might be the chemical cues to attract protozoa. Headspace volatile organic compounds (VOC) released from Listeria were collected, spiked to 0.1% peptone and tested as the chemotactic effectors. It was discovered that the Euglena cells responded quickly to Listeria VOCs including decanal, 3,5- dimethylbenzaldehyde, ethyl acetate, indicating bacterial VOCs were used by Euglena to track the location of bacteria.

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Section: Introductionmentioning

confidence: 99%

The dialogue between protozoa and bacteria in a microfluidic device

Gaines

Ludovice

et al. 2019

PLoS ONE

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“…2 B . The meandering trajectories of the animals as they approach the algae are characteristic of a type of chemotaxis sometimes referred to as stochastic chemotaxis or “chemokinesis,” to differentiate it from another type of chemotaxis in which the organism moves directly toward the attractant (21, 30, 31).…”

Section: Resultsmentioning

confidence: 99%

“…Many eukaryotic cells, including ciliated cells, exhibit chemotaxis (21, 30, 37–39). Information about the cellular mechanisms used for chemotaxis of ciliated cells comes primarily from studies of cells that swim.…”

Section: Discussionmentioning

confidence: 99%

Coherent directed movement toward food modeled in Trichoplax , a ciliated animal lacking a nervous system

Smith

Reese

Govezensky

et al. 2019

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

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Trichoplax adhaerens is a small, ciliated marine animal that glides on surfaces grazing upon algae, which it digests externally. It has no muscles or nervous system and only six cell types, all but two of which are embedded in its epithelium. The epithelial cells are joined by apical adherens junctions; neither tight junctions nor gap junctions are present. Monociliated epithelial cells on the lower surface propel gliding. The cilia beat regularly, but asynchronously, and transiently contact the substrate with each stroke. The animal moves in random directions in the absence of food. We show here that it exhibits chemotaxis, moving preferentially toward algae embedded in a disk of agar. We present a mathematical model to explain how coherent, directional movements could arise from the collective actions of a set of ciliated epithelial cells, each independently sensing and responding to a chemoattractant gradient. The model incorporates realistic values for viscoelastic properties of cells and produces coordinated movements and changes in body shape that resemble the actual movements of the animal. The model demonstrates that an animal can move coherently in search of food without any need for chemical signaling between cells and introduces a different approach to modeling behavior in primitive multicellular organisms.

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“…The swimming activity of Tetrahymena consists of straight runs and turns. The runs provide fast and straight elements of movement, while an increasing number of turns causes more winding in the path and consequently a larger tortuosity of tracks [40,41]. By modulating these swimming elements, Tetrahymena accomplishes its chemotactic responses rather than by orienting and swimming toward or away from a chemical stimulus [39,40].…”

Section: Discussionmentioning

confidence: 99%

“…By modulating these swimming elements, Tetrahymena accomplishes its chemotactic responses rather than by orienting and swimming toward or away from a chemical stimulus [39,40]. Thus, a chemoattractant molecule (e.g., proteose peptone) can induce straight (lower tortuosity) and relatively fast swimming by decreasing the frequency of directional changes, while in the case of a repellent ligand (e.g., citronellol), the number of turns can be increased, and, consequently, the movement of Tetrahymena can become more winding (higher tortuosity) and slow [41].…”

Section: Discussionmentioning

confidence: 99%

Effects of Gonadotropin-Releasing Hormone (GnRH) and Its Analogues on the Physiological Behaviors and Hormone Content of Tetrahymena pyriformis

Lajkó

Pállinger

Kovács

et al. 2019

IJMS

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The unicellular Tetrahymena distinguishes structure-related vertebrate hormones by its chemosensory reactions. In the present work, the selectivity of hormone receptors was evaluated by analyzing the effects of various gonadotropin-releasing hormone (GnRH) analogs (GnRH-I, GnRH-III) as well as truncated (Ac-SHDWKPG-NH2) and dimer derivatives ([GnRH-III(C)]2 and [GnRH-III(CGFLG)]2) of GnRH-III on (i) locomotory behaviors, (ii) cell proliferation, and (iii) intracellular hormone contents of Tetrahymena pyriformis. The migration, intracellular hormone content, and proliferation of Tetrahymena were investigated by microscope-assisted tracking analysis, flow cytometry, and a CASY TT cell counter, respectively. Depending on the length of linker sequence between the two GnRH-III monomers, the GnRH-III dimers had the opposite effect on Tetrahymena migration. [GnRH-III(CGFLG)]2 dimer had a slow, serpentine-like movement, while [GnRH-III(C)]2 dimer had a rather linear swimming pattern. All GnRH-III derivatives significantly induced cell growth after 6 h incubation. Endogenous histamine content was uniformly enhanced by Ac-SHDWKPG-NH2 and GnRH-III dimers, while some differences between the hormonal activities of GnRHs were manifested in their effects on intracellular levels of serotonin and endorphin. The GnRH peptides could directly affect Tetrahymena migration and proliferation in a structure-dependent manner, and they could indirectly regulate these reactions by paracrine/autocrine mechanisms. Present results support the theory that recognition ability and selectivity of mammalian hormone receptors can be deduced from a phylogenetically ancient level like the unicellular Tetrahymena.

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Chemosensory behaviour of Tetrahymena

Cited by 30 publications

References 24 publications

The dialogue between protozoa and bacteria in a microfluidic device

The dialogue between protozoa and bacteria in a microfluidic device

Coherent directed movement toward food modeled in Trichoplax , a ciliated animal lacking a nervous system

Effects of Gonadotropin-Releasing Hormone (GnRH) and Its Analogues on the Physiological Behaviors and Hormone Content of Tetrahymena pyriformis

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