Synchronization of Tetrahymena cell division by multiple hypoxic shocks

Rooney, David; Eiler, John J.

doi:10.1016/0014-4827(67)90336-9

Cited by 17 publications

(6 citation statements)

References 2 publications

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“…The finding that before the first synchronized division the respiration rate per cell was somewhat greater after hypoxic synchronization and much greater after hyperthermic synchronization than in exponential phase culture is consistent with the previous findings (25) nized division and much greater before the first hyperthermically synchronized division than in exponential phase culture. In the first few minutes after the last hypoxic shock, respiration rate per cell and cell volume (25) are only slightly greater than in an unsynchronized culture .…”

Section: Respiration After Synchronizationsupporting

confidence: 91%

“…The programs of intermittent hypoxia and intermittent hyperthermia and their application to Tetrahymena cultures have been previously described in detail (26), as has the preparation of the culture medium (25,26) . Briefly, Tetrahymena pyriformis GL cells in exponential phase at a population density between 30 and 40 thousand cells/ml in a proteosepeptone, liver-extract medium were synchronized with either five 20-min 34 °C periods alternated with four 40-min 28 °C periods or seven 45-min exposures to 0.15% (by volume) oxygen alternated with 45min exposures to air at 29 °C .…”

Section: Synchronizing Division With Hypoxic and Hyperthermie Shocksmentioning

confidence: 99%

“…Measurement of respiration rate of Tetrahymena cells during hypoxic shock was not undertaken because account was taken of the difficulty of maintaining in the Warburg flask the conditions of surface/volume, agitation, and oxygen concentration which exist in the large flask (26) during hypoxic shock . Therefore, hypoxia was assumed to considerably reduce respiration rate on the basis of three findings .…”

Section: Hypoxic and Hyperthermic Shocksmentioning

confidence: 99%

“…With the intention of employing the alternate procedure approach to studies of protozoan cell division, we have developed an additional technique for synchronizing Tetrahymena cells, i .e. the utilizing of intermittent hypoxia (25) applied with an automatic apparatus (26) . It was our intention to carry out studies of the biochemical patterns which accompany the division of Tetrahymena synchronized by two alternate procedures, periodic elevations of temperature and periodic reductions of oxygen concentration .…”

Section: Introductionmentioning

confidence: 99%

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EFFECTS OF DIVISION-SYNCHRONIZING HYPOXIC AND HYPERTHERMIC SHOCKS UPON TETRAHYMENA RESPIRATION AND INTRACELLULAR ATP CONCENTRATION

Rooney

Eiler

1969

The Journal of Cell Biology

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The division of Tetrahymena pyriformis GL cells was synchronized with either seven hypoxic or five hyperthermic (heat) shocks. Hyperthermic shocks of 34°C produced no reduction in respiration rate and only a 19 % decline in intracellular ATP concentration . Hypoxic shocks of 0 .15% ambient oxygen concentration depressed intracellular ATP concentration 50% . It therefore appears that hypoxic shock, but not hyperthermic shock, reverses progress of Tetrahymena toward fission by reducing ATP concentration through a reduction of the rate of oxidative phosphorylation . After the first synchronized division, whether synchronized by intermittent hypoxia or hyperthermia, total respiration rate increased exponentially at the same rate of increase as total respiration rate in an exponentially growing (log phase) Tetrahymena cell culture . Before the first synchronized division, the total respiration rate increased exponentially but more slowly than after completion of the first synchronized division . The pattern of increase of total respiration during division synchronized by either procedure was different than the pattern of increase of total respiration of synchronous cells observed by Zeuthen .

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Section: Respiration After Synchronizationsupporting

confidence: 91%

Section: Synchronizing Division With Hypoxic and Hyperthermie Shocksmentioning

confidence: 99%

Section: Hypoxic and Hyperthermic Shocksmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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EFFECTS OF DIVISION-SYNCHRONIZING HYPOXIC AND HYPERTHERMIC SHOCKS UPON TETRAHYMENA RESPIRATION AND INTRACELLULAR ATP CONCENTRATION

Rooney

Eiler

1969

The Journal of Cell Biology

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“…This suggests that a different factor is responsible for the cessation of cell division in these cultures. It is known that anaerobiosis inhibits cell division (Rasmussen 1963;Rooney and Eiler 1967). The relationship between oxygen depletion and cessation of growth in axenic batch cultures has been discussed by Levy (1973).…”

Section: Discussionmentioning

confidence: 99%

Morphological changes during the growth cycle of axenic and monoxenic Tetrahymena pyriformis

Taylor¹,

Gates²,

Berger³

1976

Can. J. Zool.

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Morphometric data were collected from Tetrahymena pyriformis (WH-14, syngen I, mating type II) grown in two different media, one axenic and one monoxenic (with Serratia marcescens), at various times during the growth cycle. Stationary phase cells differed morphometrically from exponential phase cells in different ways in the two media. It is proposed that, in the monoxenic medium, division stopped because the food resource was depleted, while in the axenic medium division was blocked before food limitation occurred.Cells in the two culture media showed consistent morphological differences during exponential phase, the axenic cells being larger (length and width), but having smaller (in length) mouths. Significant differences between cells in replicate experiments were frequently observed.

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The relationship of protein synthesis to cell division and oral development in synchronized Tetrahymena pyriformis GL‐C: An analysis employing cycloheximide

Frankel¹

1969

Journal Cellular Physiology

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The effects of cycloheximide on synchronized Tetrahymena pyriformis strain GL-C were investigated at concentrations ranging from 0.01 to 10 pg/ml.The initial inhibition of protein synthesis was nearly total (> 85% ) at 1 pg/ml and above, partial (SO-SO%) at 0.2 to 0.05pg/ml, and slight (< 30%) at O.O2pg/ml.Eventual recovery of protein synthesis to a rate approaching that of the controls took place at concentrations of lpg/ml and less. When the drug was added before a "transition point" at 55 minutes after the end of the synchronizing treatment (EST), cell division was blocked by 10 pg/ml, and delayed at concentrations of 1 pg/ml or less. The duration of delay was related to the degree of initial inhibition, and to the time required for recovery of protein synthesis; it also depended on the time after EST at which the drug was added. At a given concentration, maximum division delay was observed just prior to the "transition point;" this maximum delay was correlated with resorption of differentiating oral primordia, followed by the appearance of new primordia. The lesser delays observed at earlier times were correlated with temporary blockage of development of primordia in the "stomatogenic field" stage. Resumption of oral primordium development was, in both cases, temporally correlated with a substantial recovery of protein synthesis. After the "transition point," cell division, and completion of oral development, was delayed slightly at the lower concentrations, and more substantially at 1 and 10,ug/ml, with some division-arrest at the latter concentration. Except for the recovery phenomenon, the developmental responses elicited by cycloheximide were similar to those observed earlier with puromycin.The bearing of these findings on the mechanism of synchronization in Tetruhymenu is considered in the Discussion.Studies employing two antagonists of protein synthesis, p-fluorophenylalanine and puromycin, have provided evidence that concurrent protein synthesis is necessary to support preparation for cell division (Rasmussen and Zeuthen, '62) and oral development (Frankel, '62, '67b) in strain GL of the ciliate Tetrahymena pyriformis. The earlier studies, utilizing brief doses of p-fluorophenylalanine, demonstrated that treatment prior to a certain stage could bring about a "set-back" of cell division (Rasmussen and Zeuthen, '62) with attendant arrest or resorption of the developing oral primordium (Frankel, '62); after this stage (which is known as the "physiological transition point" or "stabilization point") the inhibitor had no effect. A later study with puromycin (Frankel, '67b) yielded generally similar results; however, it also revealed that a high concentration of the inhibitor, which caused J. CELL. PHYSIOL., 74: 135-148.

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Synchronization of Tetrahymena cell division by multiple hypoxic shocks

Cited by 17 publications

References 2 publications

EFFECTS OF DIVISION-SYNCHRONIZING HYPOXIC AND HYPERTHERMIC SHOCKS UPON TETRAHYMENA RESPIRATION AND INTRACELLULAR ATP CONCENTRATION

EFFECTS OF DIVISION-SYNCHRONIZING HYPOXIC AND HYPERTHERMIC SHOCKS UPON TETRAHYMENA RESPIRATION AND INTRACELLULAR ATP CONCENTRATION

Morphological changes during the growth cycle of axenic and monoxenic Tetrahymena pyriformis

The relationship of protein synthesis to cell division and oral development in synchronized Tetrahymena pyriformis GL‐C: An analysis employing cycloheximide

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