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Fig. 5. Cycloheximide does not affect bristle growth but does promote premature
bundle breakdown. (a) A group of same-age thoraces (dissected from a single
cohort of pupae 36 hours after puparium formation) were divided into two
groups and cultured in the presence or in the absence (control) of 1 µM
cycloheximide for 5 hours. Bristle lengths were measured from confocal images
of phalloidin-stained microchaetes. Bristle length was unaffected when
cultured in cycloheximide. (b) A group of same-age thoraces (dissected from a
single cohort of pupae 42 hours after puparium formation) were divided into
two groups and cultured in the presence or in the absence (control) of 1 µM
cycloheximide for two hours. Actin bundles were imaged by confocal microscopy
and evaluated by the criteria illustrated in
Fig. 1. A total of 56 bristles
were examined and the percentages of bristles exhibiting tapering modules or
bundle ghosts characteristic of depolymerizing bundles are presented. Of
interest here is that cycloheximide promotes the breakdown of modules usually
seen in older bristles (e.g., Fig.
1).