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Description
Alzheimer's Disease (AD) is the sixth leading cause of death in the United States and the most common form of dementia. Its cause remains unknown, but it is known to involve two hallmark pathologies: Amyloid Beta plaques and neurofibrillary tangles (NFTs). Several proteins have been implicated in the formation of

Alzheimer's Disease (AD) is the sixth leading cause of death in the United States and the most common form of dementia. Its cause remains unknown, but it is known to involve two hallmark pathologies: Amyloid Beta plaques and neurofibrillary tangles (NFTs). Several proteins have been implicated in the formation of neurofibrillary tangles, including Tau and S100B. S100B is a dimeric protein that is typically found bound to Ca(II) or Zn(II). These experiments relate to the involvement of S100B in Alzheimer's Disease-related processes and the results suggest that future research of S100B is warranted. Zn(II)-S100B was found to increase the rate at which tau assembled into paired helical filaments, as well as affect the rate at which tubulin polymerized into microtubules and the morphology of SH-SY5Y neuroblastoma cells after 72 hours of incubation. Zn(II)-S100B also increased the firing rate of hippocampal neurons after 36 hours of incubation. Together, these results suggest several possibilities: Zn(II)-S100B may be a key part of the formation of paired helical filaments (PHFs) that subsequently form NFTs. Zn(II)-S100B may also be competing with tau to bind tubulin, which could lead to an instability of microtubules and subsequent cell death. This finding aligns with the neurodegeneration that is commonly seen in AD and which could be a result of this microtubule instability. Ultimately, these results suggest that S100B is likely involved in several AD-related processes, and if the goal is to find an efficient and effective therapeutic target for AD, the relationship between S100B, particularly Zn(II)-S100B, and tau needs to be further studied.
ContributorsNaegele, Hayley (Author) / Mcgregor, Wade C (Thesis advisor) / Baluch, Debra (Committee member) / Francisco, Wilson (Committee member) / Arizona State University (Publisher)
Created2013
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Description
The intracellular motility seen in the cytoplasm of angiosperm plant pollen tubes is known as reverse fountain cytoplasmic streaming (i.e., cyclosis). This effect occurs when organelles move anterograde along the cortex of the cell and retrograde down the center of the cell. The result is a displacement of cytoplasmic volume

The intracellular motility seen in the cytoplasm of angiosperm plant pollen tubes is known as reverse fountain cytoplasmic streaming (i.e., cyclosis). This effect occurs when organelles move anterograde along the cortex of the cell and retrograde down the center of the cell. The result is a displacement of cytoplasmic volume causing a cyclic motion of organelles and bulk liquid. Visually, the organelles appear to be traveling in a backwards fountain hence the name. The use of light microscopy bioimaging in this study has documented reverse fountain cytoplasmic streaming for the first time in fungal hyphae of Rhizopus oryzae and other members in the order Mucorales (Mucoromycota). This is a unique characteristic of the mucoralean fungi, with other fungal phyla (e.g., Ascomycota, Basidiomycota) exhibiting unidirectional cytoplasmic behavior that lacks rhythmic streaming (i.e., sleeve-like streaming). The mechanism of reverse fountain cytoplasmic streaming in filamentous fungi is currently unknown. However, in angiosperm plant pollen tubes it’s correlated with the arrangement and activity of the actin cytoskeleton. Thus, the current work assumes that filamentous actin and associated proteins are directly involved with the cytoplasmic behavior in Mucorales hyphae. From an evolutionary perspective, fungi in the Mucorales may have developed reverse fountain cytoplasmic streaming as a method to transport various organelles over long and short distances. In addition, the mechanism is likely to facilitate driving of polarized hyphal growth.
ContributorsShange, Phakade Mdima (Author) / Roberson, Robert W. (Thesis advisor) / Gile, Gillian (Committee member) / Baluch, Debra (Committee member) / Arizona State University (Publisher)
Created2020