The effects of extracellular and intracellular Hop on cell migration processes
- Authors: Contu, Lara
- Date: 2014
- Subjects: Heat shock proteins , Metastasis , Cancer Chemotherapy , Molecular chaperones , Cell migration
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/193961 , vital:45410
- Description: The Hsp70/Hsp90-organising protein (Hop) is a 60 kDa co-chaperone that acts as an adaptor molecule, facilitating the transfer of client proteins between the Hsp70 and Hsp90 chaperone systems. Hop functions both intracellularly and extracellularly and has been implicated in many processes involved in cancer progression, including cell migration and invasion. Little is known about the mechanisms or domains by which extracellular Hop functions. In addition, little is known about the effects of Hop on signalling molecules involved in cell migration and invasion through regulation of actin dynamics. It was hypothesised that both extracellular and intracellular pools of Hop would regulate distinct cell migration processes by activation of cell signalling pathways or direct interactions with signalling intermediates. HS578T cells were treated with recombinant full length and truncated murine Hop proteins (overexpressed and purified in this study) to determine the effects of extracellular Hop and the independent domains on cell migration processes. Additionally, RNA interference (RNAi) techniques were used to determine the effect of Hop knockdown on cell migration related signalling intermediates and cell morphologies. A short hairpin RNA (shRNA) system for the stable knockdown of Hop was developed and used for a number of these studies. Treatment of HS578T cells with the TPR2A2B and TPR1 domains of Hop resulted in a significant decrease in cell migration and caused changes in the actin cytoskeleton and extracellular matrix proteins, gelatin and fibronectin. RhoC immunoprecipitated in a common complex with Hop and Hsp90. Hop knockdown reduced levels of actin and total RhoC, as well as active RhoC. In addition, knockdown of Hop resulted in a reduced migratory phenotype. We interpreted these data to indicate that intracellular Hop played a role in cell migration through regulation of RhoC activity, either through a direct interaction between Hop and RhoC, or an indirect interaction of RhoC with the Hsp90 multichaperone heterocomplex. Taken together, the data suggested that extracellular and intracellular Hop played distinct roles in extracellular and intracellular processes that lead to actin dynamics and cell migration. Understanding the mechanistic role of Hop in these processes is essential as it would aid in assessing the viability of Hop as a potential drug target for the treatment of metastatic cancers. , Thesis (MSc) -- Faculty of Science, Biochemistry, Microbiology and Biotechnology, 2014
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- Date Issued: 2014
An investigation into the biological treatment of platinum refinery effluent using the plant Azolla Filiculoides
- Authors: Marran, Vernon Edward
- Date: 2003
- Subjects: Uncatalogued
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/193453 , vital:45333
- Description: In order to understand the effects of metals contained in effluent and to define effluent quality suitable for safe discharge to natural water streams, it is essential to understand the effects of the interaction of metal ions with plants. The availability of metal ions and their ability to bind to plants are dependent on the chemical speciation of metals and on the biological factors governing the availability of metals within the plant cells. This thesis will address both aspects and thereby propose a combination of an appropriate chemical and biological approach to the investigation of bioaccumulation of the plant Azolla Filiculoides. Laboratory studies have shown that varying concentrations of free metal ions in solution determine efficiency of metal uptake and that metal toxicity can also be detrimental to plant life and efficiency of metal recovery from solution. Many questions however, remain unanswered with regard to the application of a biological treatment for effluent discharge. This thesis includes the determination of metal speciation combined with the study of bioaccumulation of metals in plants and their effects from test- work utilising effluent generated from a Precious Metals Refinery (PMR). Plant species are known to differ widely in their tolerance to metals, however despite an abundant knowledge on molecular, biochemical and physiological effects of metals to plants, only a few general principles have been proposed to guide the prediction of tolerance differences. The properties of protective cellular responses as well as of the molecular target sites are important components in determining the intrinsic tolerance of a particular species to a metal. The role of the whole assembly of cellular ligands in buffering metal ions within the cells will be evaluated. Standard preparation methods combined with use of Inductively Coupled Plasma Emission Spectrophotometer (1CP) used for analytical analysis will be included to reflect analytical data in providing evidence to support a conclusion. The outcome of the test work utilising the aquatic plant Azoila has proven that it can be used as a process step to re-mediate effluent generated from Precious Metal Refining operations. This process offers an alternative to the classical chemical methods widely used in the Precious Metals Refining industry proving economically viable and ensuring environmental sustainability in comparison to the current known methods of effluent treatment. , Thesis (MSc) -- Faculty of Science, Biochemistry, Microbiology and Biotechnology, 2003
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- Date Issued: 2003
An investigation into the biological treatment of platinum refinery effluent
- Authors: Smith, Roland Paul
- Date: 200u
- Subjects: Uncatalogued
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/193464 , vital:45334
- Description: This Review and project will discuss and demonstrate the use made of Biotechnology in the production and reduction of metals. It will look at how and why metal binding takes place, known platinum group metal speciation will be included. Examples of how to improve metal binding efficiency will be discussed by stimulating ligand activity by polarisation. Various biotechnical options available, with emphasis placed on the use of the aquatic fern and algae will be given as examples of biological treatment of heavy metals in particular the aquatic fern Azolla. The method of standard preparation and the use of Inductively Coupled Plasma Emission Spectrophotometer (ICP) used for analytical analysis will be included so that consideration can be given to the collection of analytical data in the provision of evidence to support or provide a conclusion. The outcome of the test work utilising the aquatic plant Azolla has proven that it can be used to remediate platinum refinery effluent. This process can offer an alternative to the classical chemical method normally used, which is economically viable and environmentally friendly in comparison to the common methods of refinery effluent treatment. , Thesis (MSc) -- Faculty of Science, Biochemistry, Microbiology and Biotechnology, 200u
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- Date Issued: 200u