Download Abstract Ferullo

Dan Ferullo
Abstract
1-29-04
The role for CheY in the rotational direction of the flagellar motor has been
further characterized (doesn’t say very much-could you leave this sentence out?).
Previous studies have proposed a model in which ligand release or synthesis of a
molecule is necessary for CheY to influence flagella. Our findings suggest a new model
in which the clockwise rotation of flagella does not require the involvement of either the
chemotactic components of the methylation system or the presence of the major
chemoattractant receptors. We have devised a system in which production of CheY
through the use of a promoter on an expression plasmid construct allows for levels of
transcription in Escherichia Coli to be adjustable. Revise sentence Various expression
levels of cheY were observed in both wild type and mutant cells that contained a deletion
plasmid ??? for other chemotactic gene products. Specifically, overproduction and
endogenous levels of CheY in both wild type and mutant cells exhibited either a shift
from a counter-clockwise rotation to a clockwise rotation. This, in effect, corresponds to
an increase in tumbling frequency in free-swimming bacteria. The results suggest that
CheY interacts with a detector on the flagellar motor, potentially through another
chemotaxis-specific gene product, to promote a clockwise rotation in flagella. (There is a
jump in the sequence of logic from the deletion of the other genes in the che pathway to
this last statement. You need to fill in the missing step.)