Characteristics of dividing and non-dividing Tetrahymena cells at different physiological states

Hellung‐Larsen, Per; Lyhne, Inger; Andersen, Anders P.; Koppelhus, Uffe

doi:10.1016/s0932-4739(11)80272-5

Cited by 16 publications

(5 citation statements)

References 18 publications

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“…Thus, the survival of a cell is not related to a certain phase of the cell cycle. This conclusion was also obtained in experiments using cells from different physiological states, such as starving cells, hypoxic cells, and upshifted cells (Hellung-Larsen et al, 1993) (data not shown).…”

Section: Resultssupporting

confidence: 67%

Surface mediated death of unconditionedTetrahymena cells: Effect of physical parameters, growth factors, hormones, and surfactants

et al. 1996

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A new form of cell death has been observed. The death occurs at liquid-air interfaces when Tetrahymena cells are grown in a chemically defined medium (CDM) at low inocula. The cells die by lysis at the liquid-air interface (medium surface), which they reach due to negative gravitaxis as well as positive aerotaxis. When the cells are grown in a closed compartment, with no liquid-air interface, the death is not observed, and the cells proliferate. Cloning of cells in CDM is thus possible. The addition of effectors such as NGF (10(-11) M), EGF (10(-10) M), PDGF (10(-10) M), and insulin (10(-7) M) to cells in CDM prevents the surface mediated death. Since detergents/surfactants like SDS (7 x 10(-5) M), NP-40 (2 x 10(-5) M), Tween 80 (10(-4))% w/v), Pluronic F-68 (10(-7) M), and the biosurfactant surfactin (10(-6) M) have the same effect, we suggest that the effectors act by stimulating the cells to exudate surfactant(s) of their own. Furthermore, lyzed cells and exudates from living cells (pre-conditioned medium) prevent the death. In conditions with liquid-air interfaces, certain physical parameters are of great importance for the survival of cells at low inocula. The parameters are the distance to the surface, the temperature, and the inoculum. By increasing the height of the medium, lowering the temperature, and increasing the inoculum of the culture, the survival can be greatly enhanced. There is no evidence for programmed cell death (PCD) or apoptosis.

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Section: Resultssupporting

confidence: 67%

Surface mediated death of unconditionedTetrahymena cells: Effect of physical parameters, growth factors, hormones, and surfactants

et al. 1996

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“…We assumed that the pH of the medium would be affected if the starvation medium had no buffer capacity. Initially, we used 10 mM Hepes-KOH, pH 7.4 (Hepes) for the starvation medium because we recently found that long-term starved cells survive better in Hepes than in 10 mA/ Tris-HCl, pH 7.4 (Tris) (Hellung-Larsen et al 1993). As shown in Table I, pH was 7.4 after starvation 2cm Figure 2.…”

Section: Influence Of Starvation Mediummentioning

confidence: 99%

“…This also seems to indicate that there is no direct relationship between the ATP pools of the cells and their ability to maintain their swimming speed. For comparison, the swimming speeds of exponentially growing cells in culture are between 0.5 and 0.6 mm s ' (Hellung-Larsen et al. 1993).…”

Section: Influence Of Oxygen Saturation Of the Stan'ation Mediummentioning

confidence: 99%

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Physiological Parameters Affecting the Chemosensory Response of Tetrahymena

Koppelhus

Hellung‐Larsen²,

Leick³

1994

The Biological Bulletin

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We have investigated the significance of a number of physiological parameters in the preparation of cells for experiments on chemokinesis in Tetrahymena. The study comprises (1) growth state of the cells, (2) composition of the starvation medium, (3) concentration of cells during starvation, (4) oxygen saturation of the starvation medium, (5) temperature during starvation, and (6) starvation period. By controlling the physiological state of the cells, we significantly improved the reproducibility of the results obtained in assays for chemokinesis in Tetrahymena. In short, cells optimal for chemokinesis at an assay temperature of 28 degrees C should be starved from the exponential growth phase in a concentration below 2 x 10(5) cells ml-1 for 10-20 h. The surface-to-volume ratio of the starvation medium--water or Hepes buffer--should be about 5 cm-1 (or more) to ensure more than 95% oxygen saturation of the starvation medium. Maximal chemosensory responses were obtained if the cells were starved at 21 degrees C. The chemokinetic potential of the cells decreased significantly, as did the levels of the ratio of ATP to ADP, if cells were starved at higher temperatures. A tentative correlation between the ATP level in the cells and the chemosensory potential of the cells has been found. We suggest that chemokinesis is a constant quality of Tetrahymena, because we found no sign that prolonged starvation or other changes applied to the cells produced an up-regulation of the chemosensory response. Apparently, starvation is obligatory only to remove the growth medium (which is itself a very potent attractant), thereby making the cells sensitive to the chemoattractants.

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“…It is commonly known that a gradual decrease in swimming speed occurs as a result of Tetrahymena starvation [ 55 ]. Our analysis clearly showed that most of the locomotor activities were significantly reduced in the starvation condition ( Figure 4 ).…”

Section: Discussionmentioning

confidence: 99%

Establishing a High-Throughput Locomotion Tracking Method for Multiple Biological Assessments in Tetrahymena

Suryanto

Vasquez

Roldan

et al. 2022

Cells

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Protozoa are eukaryotic, unicellular microorganisms that have an important ecological role, are easy to handle, and grow rapidly, which makes them suitable for ecotoxicity assessment. Previous methods for locomotion tracking in protozoa are largely based on software with the drawback of high cost and/or low operation throughput. This study aimed to develop an automated pipeline to measure the locomotion activity of the ciliated protozoan Tetrahymena thermophila using a machine learning-based software, TRex, to conduct tracking. Behavioral endpoints, including the total distance, velocity, burst movement, angular velocity, meandering, and rotation movement, were derived from the coordinates of individual cells. To validate the utility, we measured the locomotor activity in either the knockout mutant of the dynein subunit DYH7 or under starvation. Significant reduction of locomotion and alteration of behavior was detected in either the dynein mutant or in the starvation condition. We also analyzed how Tetrahymena locomotion was affected by the exposure to copper sulfate and showed that our method indeed can be used to conduct a toxicity assessment in a high-throughput manner. Finally, we performed a principal component analysis and hierarchy clustering to demonstrate that our analysis could potentially differentiate altered behaviors affected by different factors. Taken together, this study offers a robust methodology for Tetrahymena locomotion tracking in a high-throughput manner for the first time.

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Characteristics of dividing and non-dividing Tetrahymena cells at different physiological states

Cited by 16 publications

References 18 publications

Surface mediated death of unconditionedTetrahymena cells: Effect of physical parameters, growth factors, hormones, and surfactants

Surface mediated death of unconditionedTetrahymena cells: Effect of physical parameters, growth factors, hormones, and surfactants

Physiological Parameters Affecting the Chemosensory Response of Tetrahymena

Establishing a High-Throughput Locomotion Tracking Method for Multiple Biological Assessments in Tetrahymena

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