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Studies of Macrostome Formation of Low‐Transforming Tetrahymena vorax. Transformation Enhancers, Generation Time, and Membrane Fluidity 1
Author(s) -
RYALS PHILLIP E.,
SMITHSOMERVILLE HARRIETT E.
Publication year - 1986
Publication title -
the journal of protozoology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.067
H-Index - 77
eISSN - 1550-7408
pISSN - 0022-3921
DOI - 10.1111/j.1550-7408.1986.tb05627.x
Subject(s) - biophysics , chemistry , membrane , membrane fluidity , tetrahymena pyriformis , tetrahymena , fluorescence anisotropy , biochemistry , biology
. Periodically, stocks of Tetrahymena vorax , which normally yield 70–90% macrostomes when subjected to heat shock or other induction methods, become low‐transformers and yield ≥30% macrostomes. The addition to the post‐heat‐shock wash buffer (pH 6.8) of 2.7 × 10 ‐4 M Fe 3+ , 1.6 × 10 ‐5 M Cu 2+ , 1 × 10 ‐4 M retinol palmitate or the adjustment of the buffer to a pH of 4 to 5 boosts transformation significantly over controls in inorganic medium alone. The addition of Fe 2+ or Cu 1+ has a similar, but less pronounced effect on transformation. Ferric ion (2.7 × 10 ‐4 M) will significantly increase transformation in starved non‐heat‐shocked cells, whereas Fe 2+ , copper, retinol palmitate, and hydrogen ion concentration have no effect. The agents that boost transformation appear to act by delaying cell division in pre‐transformants. Membrane fluidity, as inferred by fluorescence polarization measurements of 1,6‐diphenyl‐1,3,5‐hexatriene, is altered in a consistent manner by starvation and heat shock. Enhancing agents, including compounds previously shown to boost heat‐shock‐induced macrostome formation, produce diverse shifts in membrane fluidity. Their effect on transformation of these low‐transforming cells therefore appears to be attributable to some mechanism or mechanisms other than a direct alteration of membrane physical properties.