## Abstract Cultures of heatโsynchronized __Tetrahymena pyriformis__, growing in a proteose peptone medium, were subjected to short pulses of the amino acid analogue, __p__โflurophenylalanine, and high hydrostatic pressure. The pulses of these agents were chosen so that, when applied individually,
The effect of helium and of hydrogen at high pressure on the cell division of Tetrahymena pyriformis W.
โ Scribed by A. G. Macdonald
- Publisher
- John Wiley and Sons
- Year
- 1975
- Tongue
- English
- Weight
- 938 KB
- Volume
- 85
- Category
- Article
- ISSN
- 0021-9541
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โฆ Synopsis
Abstract
The rate of cell division of Tetrahymena growing in an observational high pressure vessel was measured at selected pressures of helium, hydrogen and at high hydrostatic pressure. Pressures greater than 100 atm reduced the rate of division, but the gases inhibited division to a lesser degree than pure hydrostatic pressure. Hydrogen's effect was distinguishable from that of hydrostatic pressure at 130 atm or more, while helium's effect appeared at 175 atm. These inert gases probably counteract the action of pressure by stabilising apolar pressureโlabile targets.
๐ SIMILAR VOLUMES
Early cleavage stages of Tetrahymena pyriformis were exposed to 250 atms pressure for periods ranging from 20-200 minutes. Pressure halted cleavage which, in those cells exposed for only a short time, was resumed soon after decompression. Cells exposed to longer periods of pressure treatment failed
Intracellular ribonuclease from the ciliate Tetrahymena pyriform.is GL was purified 10-fold. After preheating for 20 minutes at 100ยฐC of the ribonuclease preparation 80% of its activity was lost. Preheating under the same conditions, however, in the presence of RNA, did not affect the enzyme activit
## Abstract Heatโsynchronized __Tetrahymena pyriformis__ have been subjected to 5โ, 15โ and 30โminute pulses of hydrostatic pressure in the range 100โ300 atm, without being simultaneously subjected to significant heats of compression. The pressureโinduced division delays depend on (1) the level of
## Abstract Warming of exponentially growing __T. pyriformis__ to 34ยฐC results in severe inhibition of nucleotide pool formation. The utilization of the pool for stable RNA synthesis is poorly affected at the high temperature. It thus appears that the synthesis and processing of ribosomal RNA precu