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The Role of Actin in Hyphal Tip Growth

This thesis investigates whether there are alternative mechanisms of tip growth in invasive and non-invasive hyphae of the fungus Neurospora crassa. The cytoskeleton protein actin is thought to play a pivotal role in hyphal tip growth, performing a multitude of tasks, one of which may be the provision of a resistive force to counter turgor pressure.

An Actin depleted zone (ADZ) was the dominant feature of invasive hyphal tips, which was largely absent from non-invasive hyphae. The Spitzenkörper was slightly larger in invasive hyphae but this size difference alone was thought insufficient to account for the exclusion of filamentous actin (F-actin) from the tip. The actin nucleating protein formin was found at sites where actin nucleation is occurring, while cofilin, a protein that severs F-actin, was found to localise where F-actin disassembly was likely to be occurring. It is suggested that these proteins are likely to play a role in controlling a dynamic cytoskeleton, rearrangements of which are required for the two modes of growth. Invasive hyphae were found to generate a higher turgor than non-invasive hyphae.

These results suggest that the F-actin rearrangements facilitated by cofilin give an ADZ that may play a role in invasive hyphal tip growth; possibly through a reduction of tip resistance; thus enabling the provision of a greater protrusive force by turgor.

Identiferoai:union.ndltd.org:canterbury.ac.nz/oai:ir.canterbury.ac.nz:10092/1910
Date January 2008
CreatorsSuei, Sandy H.Y.
PublisherUniversity of Canterbury. Biological Sciences
Source SetsUniversity of Canterbury
LanguageEnglish
Detected LanguageEnglish
TypeElectronic thesis or dissertation, Text
RightsCopyright Sandy H.Y. Suei, http://library.canterbury.ac.nz/thesis/etheses_copyright.shtml
RelationNZCU

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