subject:(oligomer formation)

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University of Waterloo

1. You, Zehou. Enhanced Diffusion in Latex Films Induced by Oligomers and Characterized by Pyrene Excimer Fluorescence.

Degree: 2019, University of Waterloo

► Pyrene excimer fluorescence (PEF) was used to investigate the effects that the presence of low molecular weight oligo(n-butyl methacrylate) (OBMA) have on the diffusion of… (more)

▼ Pyrene excimer fluorescence (PEF) was used to investigate the effects that the presence of low molecular weight oligo(n-butyl methacrylate) (OBMA) have on the diffusion of high molecular weight poly(n-butyl methacrylate) (PBMA) in latex films. In this project, a high molecular weight PBMA latex labeled with 1.9 mol% pyrene (Py-PBMA, Mw = 410 kg/mol, PDI = 2.0) was mixed with nine non-fluorescent latex particles which needed to be prepared. Among these nine particles, two unlabeled latexes (Mw = 360 kg/mol, PDI = 1.8 and Mw = 420 kg/mol, PDI = 1.9) were prepared without oligomers. Their molecular weight distribution (MWD) was slightly different from that of Py-PBMA. Four latex dispersions that incorporated four different weight fractions of an OBMA with an Mn of 3.0 kg/mol were prepared from a PBMA seed latex, whose MWD (Mw = 350 kg/mol, PDI = 1.9) was close to one of the unlabeled latex particles prepared without OBMA. Three more latex dispersions with three weight fractions of OBMAs with an Mn of 5.0 kg/mol were prepared from a PBMA seed latex, whose MWD (Mw = 460 kg/mol, PDI = 2.4) was similar to the other unlabeled latex polymerized without OBMA. Several blends of latex particles constituted of 5 wt% of Py-PBMA and 95 wt% of the non-fluorescent PBMA latex with or without oligomers were prepared and latex films were cast from these mixtures. The films were annealed at different temperatures and the fluorescence spectra of the films were acquired as a function of annealing time. They were analyzed to retrieve the fraction of mixing (fm), representing the molar fraction of Py-PBMA chains having diffused out of the Py-PBMA latex. In turn, the diffusion coefficients reflecting the diffusion of the polymer chains during film annealing were calculated from the fm values at each temperature and for different annealing times. Diffusion of the Py-PBMA chains was much enhanced upon mixing the Py-PBMA latex with the PBMA latex that contained a larger weight fraction of a same OBMA or a shorter OBMA at a same weight fraction. Master curves of the diffusion coefficient as a function of fm could be generated by determining the shift factors (aT). A plot of Ln(aT)-vs-1/T yielded the activation energy for the diffusion of the Py-PBMA chains, which was found to equal 163 ± 9 kJ/mol, regardless of the OBMA content or chain length. The efficiency (β) of OBMA as a plasticizer was determined as a function of oligomer length using the Fujita-Doolittle model. In addition, the temperature dependence of the efficiency was studied. The results showed that the plasticizer efficiency of the 3.0 kg/mol oligomer was larger than that of the 5.0 kg/mol at all temperatures studied, but that the difference in plasticizer efficiency between the two oligomers decreased for decreasing temperatures. The higher plasticizer efficiency of the 3.0 kg/mol oligomer was confirmed from a plot of Tg as a function of oligomer weight fraction, showing that Tg decreased more markedly with the 3.0 rather than the 5.0 kg/mol oligomer. In summary, this…

Subjects/Keywords: Pyrene; latex; film formation; oligomer; plasticizer

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APA (6^th Edition):

You, Z. (2019). Enhanced Diffusion in Latex Films Induced by Oligomers and Characterized by Pyrene Excimer Fluorescence. (Thesis). University of Waterloo. Retrieved from http://hdl.handle.net/10012/15145

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

You, Zehou. “Enhanced Diffusion in Latex Films Induced by Oligomers and Characterized by Pyrene Excimer Fluorescence.” 2019. Thesis, University of Waterloo. Accessed January 18, 2021. http://hdl.handle.net/10012/15145.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

You, Zehou. “Enhanced Diffusion in Latex Films Induced by Oligomers and Characterized by Pyrene Excimer Fluorescence.” 2019. Web. 18 Jan 2021.

Vancouver:

You Z. Enhanced Diffusion in Latex Films Induced by Oligomers and Characterized by Pyrene Excimer Fluorescence. [Internet] [Thesis]. University of Waterloo; 2019. [cited 2021 Jan 18]. Available from: http://hdl.handle.net/10012/15145.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

You Z. Enhanced Diffusion in Latex Films Induced by Oligomers and Characterized by Pyrene Excimer Fluorescence. [Thesis]. University of Waterloo; 2019. Available from: http://hdl.handle.net/10012/15145

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

University of Michigan

2. Liu, Chenghua. Protein interactions ofhsp27.

Degree: PhD, Pure Sciences, 1999, University of Michigan

URL: http://hdl.handle.net/2027.42/131712

► Heat shock protein (hsp) 27 is a member of the small heat shock protein family. The amount of hsp27 in cells correlates with the ability… (more)

▼ Heat shock protein (hsp) 27 is a member of the small heat shock protein family. The amount of hsp27 in cells correlates with the ability of cells to survive toxic or stressful conditions. The protective effect of hsp27 is believed to occur as a result of hsp27 stabilizing microfilaments, assisting in re-folding of denatured proteins, or by modulating the redox status of cells. Hsp27 exists in cells as oligomers and its activities have been shown to depend on the size of oligomers. Observations have also suggested that hsp27 may interact with other proteins. Thus, how hsp27 forms oligomers is a subject of interest to biologists. This thesis project has focused on the protein-protein interactions of hsp27, both with itself and with other proteins. Using the yeast two-hybrid system, I have shown that hsp27 binds to itself via a 30-amino acid region within the conserved domain shared by the small hsp family. Interaction of hsp27 with itself or with another small hsp, alphaB-crystallin, does not require the N-terminal half or the C-terminal tail of hsp27. These results indicate that hsp27 forms dimers from which larger oligomers then assemble. To identify others proteins with which hsp27 interacts, the yeast two-hybrid system was also used to screen a cDNA library prepared from rat Sertoli cells. A novel hsp27 binding protein was identified from the Sertoli cell library and has been named PASS1 (protein associated with small stress proteins 1). PASS1 was confirmed to bind to hsp27 by GST pull-down assay and by co-immunoprecipitation, primarily via a 100-amino acid region near its N-terminal terminus. PASS1 was demonstrated by Northern hybridization and Western blot to be expressed most abundantly in Sertoli cells and in kidney. Expression of PASS1 in cultured cells was shown to inhibit the ability of hsp27 to protect the cells from heat shock. This result indicates that PASS1 is unlikely a component of the cell protective mechanism of hsp27 and suggests that PASS1 may affect the oligomer structure of hsp27 by its binding to hsp27 and thus may have regulatory effects on hsp27 in vivo. Advisors/Committee Members: Welsh, Michael J. (advisor).

Subjects/Keywords: Formation; Hsp27; Ofhsp27; Oligomer; Oligomers; Protein Interactions

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Liu, C. (1999). Protein interactions ofhsp27. (Doctoral Dissertation). University of Michigan. Retrieved from http://hdl.handle.net/2027.42/131712

Chicago Manual of Style (16^th Edition):

Liu, Chenghua. “Protein interactions ofhsp27.” 1999. Doctoral Dissertation, University of Michigan. Accessed January 18, 2021. http://hdl.handle.net/2027.42/131712.

MLA Handbook (7^th Edition):

Liu, Chenghua. “Protein interactions ofhsp27.” 1999. Web. 18 Jan 2021.

Vancouver:

Liu C. Protein interactions ofhsp27. [Internet] [Doctoral dissertation]. University of Michigan; 1999. [cited 2021 Jan 18]. Available from: http://hdl.handle.net/2027.42/131712.

Council of Science Editors:

Liu C. Protein interactions ofhsp27. [Doctoral Dissertation]. University of Michigan; 1999. Available from: http://hdl.handle.net/2027.42/131712

Universitat de Valencia

3. Khorramnejad, Ayda. Structural and functional diversity of Bacillus thuringiensis toxins on animal, plant and microbial cells .

Degree: 2018, Universitat de Valencia

URL: http://hdl.handle.net/10550/68267

► Debido a los efectos nocivos de los insecticidas químicos en los ecosistemas y sobre los organismos beneficiosos, la implementación de agentes de control biológico ha… (more)

▼ Debido a los efectos nocivos de los insecticidas químicos en los ecosistemas y sobre los organismos beneficiosos, la implementación de agentes de control biológico ha recibido considerable atención. Entre los agentes de control biológico, se ha dedicado gran interés a los entomopatógenos, debido a su potencial para controlar plagas agrícolas y domésticas, vectores de enfermedades humanas y animales, sin introducir material no degradable en el medio ambiente. Bacillus thuringiensis (Bt) es el agente de control microbiano comercial más utilizado en la actualidad, con efectividad contra diferentes especies de insectos plaga. Las cepas de Bt producen cristales paraesporales proteináceos durante la fase de esporulación del crecimiento bacteriano llamados proteínas δ-endotoxina o Cry (de cristal). Además, esta bacteria, durante la fase de crecimiento vegetativo, produce otro tipo de proteínas insecticidas, como son las Cry1I, Vip y Sip. Las proteínas Cry1I no forman parte del cristal Bt, pero también se denominan "Cry" porque comparten una estructura de 3 dominios con la mayoría de las proteínas cristalinas. Las proteínas insecticidas Cry de Bt son altamente selectivas, no tóxicas para los vertebrados y rápidamente degradables. Debido a estas características, Bt ha ganado una gran importancia en el control de plagas de insectos agrícolas y muchos estudios se han centrado, en el pasado y presente, en el aislamiento y la caracterización de nuevas cepas que puedan conducir a encontrar nuevas toxinas con un espectro de actividad más amplio y mayor toxicidad insecticida. Objectivos La importancia de Bt en el control biologico de plagas, hizo que esta tesis tuviese los siguientes objetivos: - - Caracterización de nuevos aislados de Bt iraníes - - Expresión, aislamiento y purificación de nuevas proteínas insecticidas (Cry1Ia) - - Evaluación de la actividad insecticida y citotóxica de las toxinas Cry1Ia - - Estudio de la oligomerización en el modo de acción de las proteínas Cry1Ia - - Evaluación de la actividad antimicrobiana de las cepas Bt. - Determinación de los efectos bioquímicos de las cepas de Bt en células vegetales De acuerdo con estos objetivos, la tesis se ha dividido en seis partes principales que corresponden a cada uno de ellos. Materiales y Métodos Los materiales y métodos generales utilizados en este trabajo se describen a continuación. Las metodologías específicas utilizadas para alcanzar cada uno de los seis objetivos principales de esta tesis, se describirán posteriormente, bajo el título de cada uno de ellos. - Cepas bacterianas En este estudio se utilizaron un total de 130 cepas de Bt iraníes, del stock de Bt del Biological Control Laboratory (Universidad de Teherán). Además, las cepas B. thuringiensis HD1 (HD1S2005, proporcionada por Valent Bioscience, Inc., Libertyville, IL, EE. UU.) y B. thuringiensis subesp thuringiensis HD2 (Berliner, obtenida del Bacillus Genetic Stock Centre, BGSC, Universidad Estatal de Ohio, Ohio, EE. UU.), se usaron como cepas de referencia. Las cepas DHα5 y BL21… Advisors/Committee Members: Talaei-Hassanloui, Reza (advisor).

Subjects/Keywords: Bacillus thuringiensis; insect cell line; LC-MS/MS; Cry1Ia proteins; oligomer formation; anti-microbial activity; plant biochemical response; PCR screening

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Khorramnejad, A. (2018). Structural and functional diversity of Bacillus thuringiensis toxins on animal, plant and microbial cells . (Doctoral Dissertation). Universitat de Valencia. Retrieved from http://hdl.handle.net/10550/68267

Chicago Manual of Style (16^th Edition):

Khorramnejad, Ayda. “Structural and functional diversity of Bacillus thuringiensis toxins on animal, plant and microbial cells .” 2018. Doctoral Dissertation, Universitat de Valencia. Accessed January 18, 2021. http://hdl.handle.net/10550/68267.

MLA Handbook (7^th Edition):

Khorramnejad, Ayda. “Structural and functional diversity of Bacillus thuringiensis toxins on animal, plant and microbial cells .” 2018. Web. 18 Jan 2021.

Vancouver:

Khorramnejad A. Structural and functional diversity of Bacillus thuringiensis toxins on animal, plant and microbial cells . [Internet] [Doctoral dissertation]. Universitat de Valencia; 2018. [cited 2021 Jan 18]. Available from: http://hdl.handle.net/10550/68267.

Council of Science Editors:

Khorramnejad A. Structural and functional diversity of Bacillus thuringiensis toxins on animal, plant and microbial cells . [Doctoral Dissertation]. Universitat de Valencia; 2018. Available from: http://hdl.handle.net/10550/68267

Miami University

4. New, Christopher Paul. Analysis of Tha4 Function and Organization in Chloroplast Twin Arginine Transport.

Degree: PhD, Cell, Molecular and Structural Biology (CMSB), 2020, Miami University

URL: http://rave.ohiolink.edu/etdc/view?acc_num=miami1586878527570538

► The chloroplast Twin Arginine Translocase (cpTAT) system transports fully folded proteins across the thylakoid membrane in plant cells using only energy derived from the proton… (more)

▼ The chloroplast Twin Arginine Translocase (cpTAT) system transports fully folded proteins across the thylakoid membrane in plant cells using only energy derived from the proton motive force (PMF). Three membrane bound component proteins: cpTatC, Hcf106, and Tha4 function together in a transient manner to accomplish transport. However, clear mechanistic details of this process remain elusive such as how cpTAT utilizes energy stored in the PMF or how the individual component proteins interact during each step of transport. In addition, prior structural characterization of (cp)TAT proteins used truncated versions of the components. This dissertation describes work to develop methods to purify full-length Hcf106 for biophysical characterization. Additionally, this dissertation details the work to determine the function of a membrane embedded glutamate in the Tha4 transmembrane helix (TMH).A series of purification trials were carried out to isolate Hcf106 fused to maltose binding protein (MBP) by the recognition sequence of tobacco etch virus protease (TEVp). Fusion protein and protease were expressed in and purified from E. coli using affinity chromatography. Multiple parameters and additives were tested during optimization of TEVp proteolysis reactions with MBP-Hcf106. TEVp and free MBP were separated from un-cleaved MBP-Hcf106 and free Hcf106 by affinity and size exclusion chromatography. Although TEVp and free MBP were removed after an optimized proteolysis reaction, free Hcf106 showed its recalcitrant nature through resistance of separation from un-cleaved MBP-Hcf106 by size exclusion chromatography in several detergent and buffer conditions.To better understand the role of the membrane embedded Tha4 glutamate 10 (E10), Tha4 variants with glutamate to alanine (E10A) or glutamate to aspartate (E10D) substitutions were used to complement loss of cpTAT function in thylakoid membranes. Sequential glutamate substitutions in the TMH of Tha4 variant E10A were unable to restore transport while aspartate substitutions were mildly able to complement loss of function. Furthermore, organization between three structural regions in Tha4 E10/A/D variants was determined by disulfide crosslinking during various transport conditions. Tha4 E10/A/D variant oligomer formation was enhanced in the presence of functional precursor with and without PMF present. An increase in TMH hydrophobicity by alanine substitution was shown to increase Tha4 stability in isolated thylakoid membranes and to promote tighter packing interactions between adjacent Tha4 monomers. The interaction data was then used to develop a model of how Tha4 E10/A/D variant tetramers pack and reorganize in the presence of precursor. Advisors/Committee Members: Dabney-Smith, Carole (Advisor), Page, Rick (Committee Chair).

Subjects/Keywords: Biochemistry; Cellular Biology; Plant Biology; Molecular Biology; chloroplast twin arginine transport; protein transport; cpTAT; TAT; Tha4; Hcf106; protein purification; maltose binding protein affinity chromatography; oligomer formation; complementation; transmembrane domain hydrophobicity

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

New, C. P. (2020). Analysis of Tha4 Function and Organization in Chloroplast Twin Arginine Transport. (Doctoral Dissertation). Miami University. Retrieved from http://rave.ohiolink.edu/etdc/view?acc_num=miami1586878527570538

Chicago Manual of Style (16^th Edition):

New, Christopher Paul. “Analysis of Tha4 Function and Organization in Chloroplast Twin Arginine Transport.” 2020. Doctoral Dissertation, Miami University. Accessed January 18, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=miami1586878527570538.

MLA Handbook (7^th Edition):

New, Christopher Paul. “Analysis of Tha4 Function and Organization in Chloroplast Twin Arginine Transport.” 2020. Web. 18 Jan 2021.

Vancouver:

New CP. Analysis of Tha4 Function and Organization in Chloroplast Twin Arginine Transport. [Internet] [Doctoral dissertation]. Miami University; 2020. [cited 2021 Jan 18]. Available from: http://rave.ohiolink.edu/etdc/view?acc_num=miami1586878527570538.

Council of Science Editors:

New CP. Analysis of Tha4 Function and Organization in Chloroplast Twin Arginine Transport. [Doctoral Dissertation]. Miami University; 2020. Available from: http://rave.ohiolink.edu/etdc/view?acc_num=miami1586878527570538

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