+publisher:"University of Guelph" +contributor:("Dutcher, John")

University of Guelph

1. Kelly, Corey. Effect of Antimicrobial Agents on MinD Protein Oscillations in Escherichia coli.

Degree: MS, Department of Physics, 2011, University of Guelph

URL: https://atrium.lib.uoguelph.ca/xmlui/handle/10214/3135

► The Min protein system regulates cell division in the bacterium Escherichia coli. The protein MinD undergoes a pole-to-pole oscillation, antagonizing formation of the division septum… (more)

▼ The Min protein system regulates cell division in the bacterium Escherichia coli. The protein MinD undergoes a pole-to-pole oscillation, antagonizing formation of the division septum at the cell poles, thereby confining the septum formation to the mid-cell. The MinD oscillation period is 40 s at room temperature in healthy cells, but has been shown to be sensitive to stress on the cell. By fluorescently labeling MinD with green fluorescent protein (GFP), we are able to measure the MinD oscillation period as an in situ metric of cell viability using high resolution total internal reflection fluorescence (TIRF) microscopy. We have made several improvements to the method by which we measure and analyse the MinD oscillation period. A microscopy flow cell was designed and constructed and it provides temperature control and stability to a precision of 0.05 °C in addition to allowing controlled addition of bacterial cells and reagents of interest to the imaging region of the flow cell. This flow cell enabled us to make a precise measurement of the temperature dependence of the MinD oscillation period, for which we observed an Arrhenius dependence with an activation energy of 11.8 kcal/mol. We developed a centroid-tracking method, performed in a custom MATLAB program, to extract the values of the MinD oscillation periods from our time series of TIRF microscopy images. We measured the effect on the MinD oscillation period of exposure to the cationic antimicrobial peptide polymyxin B (PMB) and the related compound polymyxin B nonapeptide (PMBN), which does not have antimicrobial activity. Exposure to PMB resulted in a 60% increase in the average MinD oscillation period tau, whereas exposure to PMBN resulted in an 20% decrease in tau. After exposure to PMB and PMBN, we measured the Arrhenius temperature dependence of the MinD temperature dependence and calculated the associated activation energy Ea. We found that exposure to PMB resulted in a 40% increase in Ea, whereas exposure to PMBN did not significantly change the value of Ea. These results indicate that careful measurements of the MinD oscillation can yield information that can be helpful in evaluating the mechanism of action of antimicrobial compounds. Advisors/Committee Members: Dutcher, John (advisor).

Subjects/Keywords: e coli; antimicrobial agents; polymyxin b; total internal reflection microscopy; tirf; min protein

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APA (6^th Edition):

Kelly, C. (2011). Effect of Antimicrobial Agents on MinD Protein Oscillations in Escherichia coli. (Masters Thesis). University of Guelph. Retrieved from https://atrium.lib.uoguelph.ca/xmlui/handle/10214/3135

Chicago Manual of Style (16^th Edition):

Kelly, Corey. “Effect of Antimicrobial Agents on MinD Protein Oscillations in Escherichia coli.” 2011. Masters Thesis, University of Guelph. Accessed January 19, 2021. https://atrium.lib.uoguelph.ca/xmlui/handle/10214/3135.

MLA Handbook (7^th Edition):

Kelly, Corey. “Effect of Antimicrobial Agents on MinD Protein Oscillations in Escherichia coli.” 2011. Web. 19 Jan 2021.

Vancouver:

Kelly C. Effect of Antimicrobial Agents on MinD Protein Oscillations in Escherichia coli. [Internet] [Masters thesis]. University of Guelph; 2011. [cited 2021 Jan 19]. Available from: https://atrium.lib.uoguelph.ca/xmlui/handle/10214/3135.

Council of Science Editors:

Kelly C. Effect of Antimicrobial Agents on MinD Protein Oscillations in Escherichia coli. [Masters Thesis]. University of Guelph; 2011. Available from: https://atrium.lib.uoguelph.ca/xmlui/handle/10214/3135

University of Guelph

2. Paulin, Hilary. Pattern Recognition in Single Molecule Force Spectroscopy Data.

Degree: MS, Department of Physics, 2013, University of Guelph

URL: https://atrium.lib.uoguelph.ca/xmlui/handle/10214/7466

► We have developed an analytical technique for single molecule force spectroscopy (SMFS) data that avoids filtering prior to analysis and performs pattern recognition to identify… (more)

Subjects/Keywords: biophysics; single molecule biophysics; single molecule force spectroscopy; alpha-lactalbumin; bacteriorhodopsin; pattern recognition; hierarchical clustering; clustering; force spectroscopy; protein adsorption; protein structure; surface curvature; atomic force microscopy

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APA (6^th Edition):

Paulin, H. (2013). Pattern Recognition in Single Molecule Force Spectroscopy Data. (Masters Thesis). University of Guelph. Retrieved from https://atrium.lib.uoguelph.ca/xmlui/handle/10214/7466

Chicago Manual of Style (16^th Edition):

Paulin, Hilary. “Pattern Recognition in Single Molecule Force Spectroscopy Data.” 2013. Masters Thesis, University of Guelph. Accessed January 19, 2021. https://atrium.lib.uoguelph.ca/xmlui/handle/10214/7466.

MLA Handbook (7^th Edition):

Paulin, Hilary. “Pattern Recognition in Single Molecule Force Spectroscopy Data.” 2013. Web. 19 Jan 2021.

Vancouver:

Paulin H. Pattern Recognition in Single Molecule Force Spectroscopy Data. [Internet] [Masters thesis]. University of Guelph; 2013. [cited 2021 Jan 19]. Available from: https://atrium.lib.uoguelph.ca/xmlui/handle/10214/7466.

Council of Science Editors:

Paulin H. Pattern Recognition in Single Molecule Force Spectroscopy Data. [Masters Thesis]. University of Guelph; 2013. Available from: https://atrium.lib.uoguelph.ca/xmlui/handle/10214/7466

University of Guelph

3. Moscaritolo, Robert Frank. Quantifying Bacterial Crowd Surfing in Pseudomonas aeruginosa.

Degree: MS, Department of Physics, 2013, University of Guelph

URL: https://atrium.lib.uoguelph.ca/xmlui/handle/10214/7489

► Type IV pili (T4P) are adhesive protein filaments that can be extended and retracted by certain classes of Gram-negative bacteria. The motion of bacteria on… (more)

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APA (6^th Edition):

Moscaritolo, R. F. (2013). Quantifying Bacterial Crowd Surfing in Pseudomonas aeruginosa. (Masters Thesis). University of Guelph. Retrieved from https://atrium.lib.uoguelph.ca/xmlui/handle/10214/7489

Chicago Manual of Style (16^th Edition):

Moscaritolo, Robert Frank. “Quantifying Bacterial Crowd Surfing in Pseudomonas aeruginosa.” 2013. Masters Thesis, University of Guelph. Accessed January 19, 2021. https://atrium.lib.uoguelph.ca/xmlui/handle/10214/7489.

MLA Handbook (7^th Edition):

Moscaritolo, Robert Frank. “Quantifying Bacterial Crowd Surfing in Pseudomonas aeruginosa.” 2013. Web. 19 Jan 2021.

Vancouver:

Moscaritolo RF. Quantifying Bacterial Crowd Surfing in Pseudomonas aeruginosa. [Internet] [Masters thesis]. University of Guelph; 2013. [cited 2021 Jan 19]. Available from: https://atrium.lib.uoguelph.ca/xmlui/handle/10214/7489.

Council of Science Editors:

Moscaritolo RF. Quantifying Bacterial Crowd Surfing in Pseudomonas aeruginosa. [Masters Thesis]. University of Guelph; 2013. Available from: https://atrium.lib.uoguelph.ca/xmlui/handle/10214/7489

University of Guelph

4. Lu, Shun. Atomic Force Microscopy Measurements of Type IV Pili and the Nanomechanical Response of Bacteria to Cationic Antimicrobial Peptides.

Degree: PhD, Department of Physics, 2014, University of Guelph

URL: https://atrium.lib.uoguelph.ca/xmlui/handle/10214/7797

► We have used an AFM-based creep deformation technique to measure changes to the viscoelastic properties of individual Pseudomonas aeruginosa PAO1 cells after exposure to two… (more)

▼ We have used an AFM-based creep deformation technique to measure changes to the viscoelastic properties of individual Pseudomonas aeruginosa PAO1 cells after exposure to two cationic peptides: polymyxin B (PMB), and polymyxin B nonapeptide (PMBN), which are structurally-related compounds. These measurements provide a distinctive signature for the loss of integrity of the bacterial cell envelope following exposure to the peptides. Measurements performed before and after sufficiently long exposure to the peptides, as well as time-resolved measurements following the introduction of the peptides, revealed large changes to the viscoelastic parameters that we can attribute to different components of the bacterial cells. Differences between the results for exposure to the two peptides are consistent with the difference between their membrane permeabilizing effects. Large differences were also observed for exposure to high and low concentrations of PMB. These measurements provide new, unique insight into the kinetics and mechanism of action of antimicrobial peptides on bacterial cells. We also applied AFM as a single molecule force microscopy (SMFM) to study the mechanical properties of type IV pili (T4P) filaments on P. aeruginosa bacterial cells as polar appendages. Force-separation curves, obtained during retraction of AFM tip away from underlying surfaces, show two different behaviours: stretching T4P with a fixed contact point (described by the Worm-like chain (WLC) model) and a forced desorption of T4P filaments off the underlying surfaces (indicated by a force plateau). The results can provide valuable insights on questions difficult to answer in previous studies. We showed that T4P filaments can bind to surfaces with multiple adhesins distributed along the pili instead of a single adhesin located at the distal end. Moreover, different rupture forces on gold and mica surfaces suggest that the breakage in force curves is due to the failure of adhesion between the pili filaments and underlying surfaces. A more accurate persistence length of 1.4 nm was measured for type IV pili filament, using a 600 nm colloidal probe to reduce AFM tip height effect in force curves. Our study can shed new light on bacterial pili adhesion mechanism and its role to sustain external forces in flows. Advisors/Committee Members: Dutcher, John (advisor).

Subjects/Keywords: Bacteria; Viscoelasticity; Cationic Antimicrobial Peptide; Type IV Pili; Atomic Force Microscopy

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APA (6^th Edition):

Lu, S. (2014). Atomic Force Microscopy Measurements of Type IV Pili and the Nanomechanical Response of Bacteria to Cationic Antimicrobial Peptides. (Doctoral Dissertation). University of Guelph. Retrieved from https://atrium.lib.uoguelph.ca/xmlui/handle/10214/7797

Chicago Manual of Style (16^th Edition):

Lu, Shun. “Atomic Force Microscopy Measurements of Type IV Pili and the Nanomechanical Response of Bacteria to Cationic Antimicrobial Peptides.” 2014. Doctoral Dissertation, University of Guelph. Accessed January 19, 2021. https://atrium.lib.uoguelph.ca/xmlui/handle/10214/7797.

MLA Handbook (7^th Edition):

Lu, Shun. “Atomic Force Microscopy Measurements of Type IV Pili and the Nanomechanical Response of Bacteria to Cationic Antimicrobial Peptides.” 2014. Web. 19 Jan 2021.

Vancouver:

Lu S. Atomic Force Microscopy Measurements of Type IV Pili and the Nanomechanical Response of Bacteria to Cationic Antimicrobial Peptides. [Internet] [Doctoral dissertation]. University of Guelph; 2014. [cited 2021 Jan 19]. Available from: https://atrium.lib.uoguelph.ca/xmlui/handle/10214/7797.

Council of Science Editors:

Lu S. Atomic Force Microscopy Measurements of Type IV Pili and the Nanomechanical Response of Bacteria to Cationic Antimicrobial Peptides. [Doctoral Dissertation]. University of Guelph; 2014. Available from: https://atrium.lib.uoguelph.ca/xmlui/handle/10214/7797

University of Guelph

5. Parg, Richard. Nanomechanical Measurements of Viscoelastic Properties of Bacterial Cells: Effect of Antimicrobial Peptides and Challenges Associated with Measurements in Buffer.

Degree: MS, Department of Physics, 2016, University of Guelph

URL: https://atrium.lib.uoguelph.ca/xmlui/handle/10214/9585

► The effectiveness of antimicrobial compounds can be easily screened; however, their mechanism of action is much more difficult to determine. Many compounds act by compromising… (more)

Subjects/Keywords: Atomic Force Microscopy; Bacteria; Pseudomonas aeruginosa; Antibiotics; Polymyxin; Force Spectroscopy; Creep Deformation; Viscoelasticity

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APA (6^th Edition):

Parg, R. (2016). Nanomechanical Measurements of Viscoelastic Properties of Bacterial Cells: Effect of Antimicrobial Peptides and Challenges Associated with Measurements in Buffer. (Masters Thesis). University of Guelph. Retrieved from https://atrium.lib.uoguelph.ca/xmlui/handle/10214/9585

Chicago Manual of Style (16^th Edition):

Parg, Richard. “Nanomechanical Measurements of Viscoelastic Properties of Bacterial Cells: Effect of Antimicrobial Peptides and Challenges Associated with Measurements in Buffer.” 2016. Masters Thesis, University of Guelph. Accessed January 19, 2021. https://atrium.lib.uoguelph.ca/xmlui/handle/10214/9585.

MLA Handbook (7^th Edition):

Parg, Richard. “Nanomechanical Measurements of Viscoelastic Properties of Bacterial Cells: Effect of Antimicrobial Peptides and Challenges Associated with Measurements in Buffer.” 2016. Web. 19 Jan 2021.

Vancouver:

Parg R. Nanomechanical Measurements of Viscoelastic Properties of Bacterial Cells: Effect of Antimicrobial Peptides and Challenges Associated with Measurements in Buffer. [Internet] [Masters thesis]. University of Guelph; 2016. [cited 2021 Jan 19]. Available from: https://atrium.lib.uoguelph.ca/xmlui/handle/10214/9585.

Council of Science Editors:

Parg R. Nanomechanical Measurements of Viscoelastic Properties of Bacterial Cells: Effect of Antimicrobial Peptides and Challenges Associated with Measurements in Buffer. [Masters Thesis]. University of Guelph; 2016. Available from: https://atrium.lib.uoguelph.ca/xmlui/handle/10214/9585

University of Guelph

6. Shamana, Hurmiz. Rheology of Aqueous Dispersions of Phytoglycogen Nanoparticles.

Degree: MS, Department of Physics, 2017, University of Guelph

URL: https://atrium.lib.uoguelph.ca/xmlui/handle/10214/11514

► Phytoglycogen nanoparticles are a promising, new nanomaterial with many applications in the personal care, food and pharmaceutical industries. These applications rely on exceptional properties that… (more)

Subjects/Keywords: Physics; Nanoparticles; Rheology; Phytoglycogen; Viscosity; Storage Modulus; Loss Modulus; Colloids; Colloidal Dispersions; Hard Sphere Colloids; Soft Sphere Colloids; Volume Fraction

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APA (6^th Edition):

Shamana, H. (2017). Rheology of Aqueous Dispersions of Phytoglycogen Nanoparticles. (Masters Thesis). University of Guelph. Retrieved from https://atrium.lib.uoguelph.ca/xmlui/handle/10214/11514

Chicago Manual of Style (16^th Edition):

Shamana, Hurmiz. “Rheology of Aqueous Dispersions of Phytoglycogen Nanoparticles.” 2017. Masters Thesis, University of Guelph. Accessed January 19, 2021. https://atrium.lib.uoguelph.ca/xmlui/handle/10214/11514.

MLA Handbook (7^th Edition):

Shamana, Hurmiz. “Rheology of Aqueous Dispersions of Phytoglycogen Nanoparticles.” 2017. Web. 19 Jan 2021.

Vancouver:

Shamana H. Rheology of Aqueous Dispersions of Phytoglycogen Nanoparticles. [Internet] [Masters thesis]. University of Guelph; 2017. [cited 2021 Jan 19]. Available from: https://atrium.lib.uoguelph.ca/xmlui/handle/10214/11514.

Council of Science Editors:

Shamana H. Rheology of Aqueous Dispersions of Phytoglycogen Nanoparticles. [Masters Thesis]. University of Guelph; 2017. Available from: https://atrium.lib.uoguelph.ca/xmlui/handle/10214/11514

University of Guelph

7. Sampson, Joshua. Synthesis of Gold Nanoparticles via Laser Ablation in the Presence of Phytoglycogen.

Degree: MS, Department of Physics, 2019, University of Guelph

URL: https://atrium.lib.uoguelph.ca/xmlui/handle/10214/17674

► Phytoglycogen is a naturally occurring glucose-based polymer that has promising applications in personal care, nutrition, and biomedicine. Gold nanoparticles were generated using two-step laser ablation… (more)

Subjects/Keywords: gold nanoparticles; laser ablation; phytoglycogen; 4-nitrophenol reduction; catalysis; PLAL

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APA (6^th Edition):

Sampson, J. (2019). Synthesis of Gold Nanoparticles via Laser Ablation in the Presence of Phytoglycogen. (Masters Thesis). University of Guelph. Retrieved from https://atrium.lib.uoguelph.ca/xmlui/handle/10214/17674

Chicago Manual of Style (16^th Edition):

Sampson, Joshua. “Synthesis of Gold Nanoparticles via Laser Ablation in the Presence of Phytoglycogen.” 2019. Masters Thesis, University of Guelph. Accessed January 19, 2021. https://atrium.lib.uoguelph.ca/xmlui/handle/10214/17674.

MLA Handbook (7^th Edition):

Sampson, Joshua. “Synthesis of Gold Nanoparticles via Laser Ablation in the Presence of Phytoglycogen.” 2019. Web. 19 Jan 2021.

Vancouver:

Sampson J. Synthesis of Gold Nanoparticles via Laser Ablation in the Presence of Phytoglycogen. [Internet] [Masters thesis]. University of Guelph; 2019. [cited 2021 Jan 19]. Available from: https://atrium.lib.uoguelph.ca/xmlui/handle/10214/17674.

Council of Science Editors:

Sampson J. Synthesis of Gold Nanoparticles via Laser Ablation in the Presence of Phytoglycogen. [Masters Thesis]. University of Guelph; 2019. Available from: https://atrium.lib.uoguelph.ca/xmlui/handle/10214/17674

University of Guelph

8. Hiles, Melanie. Classifying Formulations and Tracking Accelerated Aging of Crosslinked Polyethylene Pipes by Applying Machine Learning Concepts to Infrared Spectra.

Degree: MS, Department of Physics, 2019, University of Guelph

URL: https://atrium.lib.uoguelph.ca/xmlui/handle/10214/21204

► Crosslinked polyethylene (PEX-a) pipes are emerging as promising replacements for traditional metal or concrete pipes used for water, gas, and sewage transport. However, PEX-a is… (more)

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APA (6^th Edition):

Hiles, M. (2019). Classifying Formulations and Tracking Accelerated Aging of Crosslinked Polyethylene Pipes by Applying Machine Learning Concepts to Infrared Spectra. (Masters Thesis). University of Guelph. Retrieved from https://atrium.lib.uoguelph.ca/xmlui/handle/10214/21204

Chicago Manual of Style (16^th Edition):

Hiles, Melanie. “Classifying Formulations and Tracking Accelerated Aging of Crosslinked Polyethylene Pipes by Applying Machine Learning Concepts to Infrared Spectra.” 2019. Masters Thesis, University of Guelph. Accessed January 19, 2021. https://atrium.lib.uoguelph.ca/xmlui/handle/10214/21204.

MLA Handbook (7^th Edition):

Hiles, Melanie. “Classifying Formulations and Tracking Accelerated Aging of Crosslinked Polyethylene Pipes by Applying Machine Learning Concepts to Infrared Spectra.” 2019. Web. 19 Jan 2021.

Vancouver:

Hiles M. Classifying Formulations and Tracking Accelerated Aging of Crosslinked Polyethylene Pipes by Applying Machine Learning Concepts to Infrared Spectra. [Internet] [Masters thesis]. University of Guelph; 2019. [cited 2021 Jan 19]. Available from: https://atrium.lib.uoguelph.ca/xmlui/handle/10214/21204.

Council of Science Editors:

Hiles M. Classifying Formulations and Tracking Accelerated Aging of Crosslinked Polyethylene Pipes by Applying Machine Learning Concepts to Infrared Spectra. [Masters Thesis]. University of Guelph; 2019. Available from: https://atrium.lib.uoguelph.ca/xmlui/handle/10214/21204

University of Guelph

9. Shelton, Erin. Quantifying Bacterial Motion in Twitching Colonies and the Effect of the Agar-Glass Interface on Bacterial Twitching Motility.

Degree: PhD, Department of Physics, 2020, University of Guelph

URL: https://atrium.lib.uoguelph.ca/xmlui/handle/10214/21215

► We have used bright-field optical microscopy, together with a custom-built, temperature- and humidity-controlled environmental chamber, to study the growth of colonies of Pseudomonas aeruginosa PAO1… (more)

▼ We have used bright-field optical microscopy, together with a custom-built, temperature- and humidity-controlled environmental chamber, to study the growth of colonies of Pseudomonas aeruginosa PAO1 due to twitching motility driven by type IV pili. The advancing front of colonies consisted of finger-like protrusions (fingers) containing many bacterial cells, with the cells within the expanding colony moving within a lattice-like pattern. We studied the expansion of twitching colonies at the interface between agar and glass for a range of agar concentrations 1.0 % w/v < C < 1.9% w/v, and we interpreted the microscopy results by characterizing the adhesion and local agar concentration at the interface using micropipette deflection and Attenuated Total Reflectance–Fourier Transform Infrared (ATR–FTIR) spectroscopy. To analyze the collective morphology and dynamics of the fingers, we used a combination of custom particle image velocimetry and Fourier analysis techniques. For agar concentrations below C ≤ 1.5% w/v, the average finger width and the density of the lattice region increased with increasing C, whereas the average edge speed remained constant. We observed a transition at C ~ 1.6% w/v in which the average edge speed dropped significantly while the average finger width remained constant. For C> 1.7% w/v, all measured quantities remained constant and the colonies were visually indistinguishable. We attribute this transition to a corresponding increase in the agar-glass adhesion that occurred because of an enhanced local concentration of agarose helices at the agar-glass interface at large agar concentrations. During the outward expansion of fingers along the interface, cells can vertically displace the agar to form multilayered regions. We observed a transition from monolayer to stable multilayer coverage within fingers at C = 1.5% w/v. We studied this transition by characterizing multilayer formation and dissolution, and transient and stable multilayer regions within fingers. We observed that a minimum finger width was required for multilayer stability, and we described the dependence of multilayer lifetime on finger width using a simple nucleation model. Advisors/Committee Members: Dutcher, John (advisor).

Subjects/Keywords: twitching motility; bacterial collective motion; agar-glass adhesion; pseudomonas aeruginosa; micropipette deflection; collective motion

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APA (6^th Edition):

Shelton, E. (2020). Quantifying Bacterial Motion in Twitching Colonies and the Effect of the Agar-Glass Interface on Bacterial Twitching Motility. (Doctoral Dissertation). University of Guelph. Retrieved from https://atrium.lib.uoguelph.ca/xmlui/handle/10214/21215

Chicago Manual of Style (16^th Edition):

Shelton, Erin. “Quantifying Bacterial Motion in Twitching Colonies and the Effect of the Agar-Glass Interface on Bacterial Twitching Motility.” 2020. Doctoral Dissertation, University of Guelph. Accessed January 19, 2021. https://atrium.lib.uoguelph.ca/xmlui/handle/10214/21215.

MLA Handbook (7^th Edition):

Shelton, Erin. “Quantifying Bacterial Motion in Twitching Colonies and the Effect of the Agar-Glass Interface on Bacterial Twitching Motility.” 2020. Web. 19 Jan 2021.

Vancouver:

Shelton E. Quantifying Bacterial Motion in Twitching Colonies and the Effect of the Agar-Glass Interface on Bacterial Twitching Motility. [Internet] [Doctoral dissertation]. University of Guelph; 2020. [cited 2021 Jan 19]. Available from: https://atrium.lib.uoguelph.ca/xmlui/handle/10214/21215.

Council of Science Editors:

Shelton E. Quantifying Bacterial Motion in Twitching Colonies and the Effect of the Agar-Glass Interface on Bacterial Twitching Motility. [Doctoral Dissertation]. University of Guelph; 2020. Available from: https://atrium.lib.uoguelph.ca/xmlui/handle/10214/21215

10. Reiter, Kyle. Analysis of Enzymatic Degradation of Cellulose Microfibrils by Quantitative Surface Plasmon Resonance Imaging.

Degree: MS, Department of Physics, 2012, University of Guelph

URL: https://atrium.lib.uoguelph.ca/xmlui/handle/10214/4895

► Cellulose is the most plentiful biopolymer on the planet, and as such, is a large potential energy source. Converting cellulose into ethanol first requires the… (more)

▼ Cellulose is the most plentiful biopolymer on the planet, and as such, is a large potential energy source. Converting cellulose into ethanol first requires the disruption of the crystallinity of cellulose fibers and subsequent hydrolysis into glucose. The glucose can then be fermented, producing ethanol. The conversion of cellulose fibers to glucose is an energy intensive and costly step, which is a barrier to industrial production of cellulosic ethanol. The use of enzymes to facilitate this conversion is a promising approach. In the present study, the action of individual enzymes and combinations of enzymes from the Hypocrea jecorina secretome on bacterial cellulose fibers has been studied, to better understand their individual and synergistic action. I have used a custom Surface Plasmon Resonance imaging (SPRi) device to measure changes in the thickness of cellulose fiber coverage of a thioglucose-functionalized gold substrate upon exposure to enzymes. The cellulose fibers were deposited using a Langmuir-Blodgett technique, resulting in non-uniform cellulose coverage of the substrate. By defining local Regions of Interest (ROIs) of the cellulose-covered gold film, and by measuring the SPR curves at elevated temperature for the ROIs as a function of time, we are able to determine the rate and extent of degradation of the cellulose fibers within individual ROIs. We have fit the change in SPR angle over time after exposure to enzyme to an exponential decay function that allows us to determine the average time constant of action of these enzymes on the deposited cellulose fibers. We have used the above procedure to measure the average time constants of action and the average degradation fraction (the change in average thickness divided by the initial average thickness) of cellulose fibers exposed to CBH-1, CBH-2, and EG-1, as well as combinations of these enzymes. We have measured an increase in the average degradation fraction and a decrease in the average time constants of action for cellulose fibers exposed to 23 μg/mL CBH-2 compared to fibers exposed to the same concentration of CBH-1. Additionally, for concurrent exposure of CBH-1 and EG-1 (with individual concentrations of 23 μg/mL), as well as concurrent introduction of CBH-1, CBH-2 and EG-1, we observed increases in the average degradation fraction and decreases in average time constants relative to the values measured for the individual enzymes. These measurements allow us to determine the relative activity of these enzymes and they demonstrate cooperativity and complementarity of action of the different enzymes. Advisors/Committee Members: Dutcher, John (advisor).

Subjects/Keywords: Cellulose; biofuel; endoglucanase; cellobiohydrolase; Surface Plasmon Resonance

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APA (6^th Edition):

Reiter, K. (2012). Analysis of Enzymatic Degradation of Cellulose Microfibrils by Quantitative Surface Plasmon Resonance Imaging. (Masters Thesis). University of Guelph. Retrieved from https://atrium.lib.uoguelph.ca/xmlui/handle/10214/4895

Chicago Manual of Style (16^th Edition):

Reiter, Kyle. “Analysis of Enzymatic Degradation of Cellulose Microfibrils by Quantitative Surface Plasmon Resonance Imaging.” 2012. Masters Thesis, University of Guelph. Accessed January 19, 2021. https://atrium.lib.uoguelph.ca/xmlui/handle/10214/4895.

MLA Handbook (7^th Edition):

Reiter, Kyle. “Analysis of Enzymatic Degradation of Cellulose Microfibrils by Quantitative Surface Plasmon Resonance Imaging.” 2012. Web. 19 Jan 2021.

Vancouver:

Reiter K. Analysis of Enzymatic Degradation of Cellulose Microfibrils by Quantitative Surface Plasmon Resonance Imaging. [Internet] [Masters thesis]. University of Guelph; 2012. [cited 2021 Jan 19]. Available from: https://atrium.lib.uoguelph.ca/xmlui/handle/10214/4895.

Council of Science Editors:

Reiter K. Analysis of Enzymatic Degradation of Cellulose Microfibrils by Quantitative Surface Plasmon Resonance Imaging. [Masters Thesis]. University of Guelph; 2012. Available from: https://atrium.lib.uoguelph.ca/xmlui/handle/10214/4895

11. Atkinson, John. Structure and Dynamics of Aqueous Dispersions of Highly-Branched Monodisperse Phytoglycogen Nanoparticles.

Degree: MS, Department of Physics, 2015, University of Guelph

URL: https://atrium.lib.uoguelph.ca/xmlui/handle/10214/9127

► Phytoglycogen is a natural monodisperse polysaccharide nanoparticle isolated from sweet corn. The particles are highly hydrophilic resulting in high water retention, low viscosity, and extraordinary… (more)

Subjects/Keywords: Colloid; Polysaccharide Nanoparticles; Dendrimer; Hydration Water

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APA (6^th Edition):

Atkinson, J. (2015). Structure and Dynamics of Aqueous Dispersions of Highly-Branched Monodisperse Phytoglycogen Nanoparticles. (Masters Thesis). University of Guelph. Retrieved from https://atrium.lib.uoguelph.ca/xmlui/handle/10214/9127

Chicago Manual of Style (16^th Edition):

Atkinson, John. “Structure and Dynamics of Aqueous Dispersions of Highly-Branched Monodisperse Phytoglycogen Nanoparticles.” 2015. Masters Thesis, University of Guelph. Accessed January 19, 2021. https://atrium.lib.uoguelph.ca/xmlui/handle/10214/9127.

MLA Handbook (7^th Edition):

Atkinson, John. “Structure and Dynamics of Aqueous Dispersions of Highly-Branched Monodisperse Phytoglycogen Nanoparticles.” 2015. Web. 19 Jan 2021.

Vancouver:

Atkinson J. Structure and Dynamics of Aqueous Dispersions of Highly-Branched Monodisperse Phytoglycogen Nanoparticles. [Internet] [Masters thesis]. University of Guelph; 2015. [cited 2021 Jan 19]. Available from: https://atrium.lib.uoguelph.ca/xmlui/handle/10214/9127.

Council of Science Editors:

Atkinson J. Structure and Dynamics of Aqueous Dispersions of Highly-Branched Monodisperse Phytoglycogen Nanoparticles. [Masters Thesis]. University of Guelph; 2015. Available from: https://atrium.lib.uoguelph.ca/xmlui/handle/10214/9127

12. Shelton, Erin. Quantifying Spatiotemporal Patterns in the Expansion of Twitching Bacterial Colonies.

Degree: MS, Department of Physics, 2015, University of Guelph

URL: https://atrium.lib.uoguelph.ca/xmlui/handle/10214/9166

► Type IV pili (T4P) are protein filaments used by certain Gram-negative bacteria for a mode of surface motility called twitching. We have developed experimental and… (more)

Subjects/Keywords: collective motion; bacterial twitching motility; type iv pili; agar stiffness

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APA (6^th Edition):

Shelton, E. (2015). Quantifying Spatiotemporal Patterns in the Expansion of Twitching Bacterial Colonies. (Masters Thesis). University of Guelph. Retrieved from https://atrium.lib.uoguelph.ca/xmlui/handle/10214/9166

Chicago Manual of Style (16^th Edition):

Shelton, Erin. “Quantifying Spatiotemporal Patterns in the Expansion of Twitching Bacterial Colonies.” 2015. Masters Thesis, University of Guelph. Accessed January 19, 2021. https://atrium.lib.uoguelph.ca/xmlui/handle/10214/9166.

MLA Handbook (7^th Edition):

Shelton, Erin. “Quantifying Spatiotemporal Patterns in the Expansion of Twitching Bacterial Colonies.” 2015. Web. 19 Jan 2021.

Vancouver:

Shelton E. Quantifying Spatiotemporal Patterns in the Expansion of Twitching Bacterial Colonies. [Internet] [Masters thesis]. University of Guelph; 2015. [cited 2021 Jan 19]. Available from: https://atrium.lib.uoguelph.ca/xmlui/handle/10214/9166.

Council of Science Editors:

Shelton E. Quantifying Spatiotemporal Patterns in the Expansion of Twitching Bacterial Colonies. [Masters Thesis]. University of Guelph; 2015. Available from: https://atrium.lib.uoguelph.ca/xmlui/handle/10214/9166

13. Mogyoros, Joshua. Flexibility of bacterial type IV pili determined using atomic force microscopy.

Degree: MS, Department of Physics, 2016, University of Guelph

URL: https://atrium.lib.uoguelph.ca/xmlui/handle/10214/10129

► Type IV pili (T4P) are very thin protein filaments extended and retracted from the surface of certain Gram-negative bacteria. T4P play a major role in… (more)

Subjects/Keywords: type IV pili; Pseudomonas aeruginosa; atomic force microscopy; force spectroscopy; polymer physics; biophysics; persistence length; bacteria; physics; biology; biological physics; bacteria; pili; pilus; flexibility; T4P; single cell force spectroscopy; AFM; SCFS; P. aeruginosa; TIRF; total internal reflection fluorescence; worm-like chain model; WLC

…Electron Microscope in the Nanoscience Laboratory at the University of Guelph (Figure 2.5…

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APA (6^th Edition):

Mogyoros, J. (2016). Flexibility of bacterial type IV pili determined using atomic force microscopy. (Masters Thesis). University of Guelph. Retrieved from https://atrium.lib.uoguelph.ca/xmlui/handle/10214/10129

Chicago Manual of Style (16^th Edition):

Mogyoros, Joshua. “Flexibility of bacterial type IV pili determined using atomic force microscopy.” 2016. Masters Thesis, University of Guelph. Accessed January 19, 2021. https://atrium.lib.uoguelph.ca/xmlui/handle/10214/10129.

MLA Handbook (7^th Edition):

Mogyoros, Joshua. “Flexibility of bacterial type IV pili determined using atomic force microscopy.” 2016. Web. 19 Jan 2021.

Vancouver:

Mogyoros J. Flexibility of bacterial type IV pili determined using atomic force microscopy. [Internet] [Masters thesis]. University of Guelph; 2016. [cited 2021 Jan 19]. Available from: https://atrium.lib.uoguelph.ca/xmlui/handle/10214/10129.

Council of Science Editors:

Mogyoros J. Flexibility of bacterial type IV pili determined using atomic force microscopy. [Masters Thesis]. University of Guelph; 2016. Available from: https://atrium.lib.uoguelph.ca/xmlui/handle/10214/10129

14. Charlesworth, Kathleen. The Creation of a Phytoglycogen-Functionalized SPR Sensor Surface and the Binding of Concanavalin A to Phytoglycogen.

Degree: MS, Department of Physics, 2019, University of Guelph

URL: https://atrium.lib.uoguelph.ca/xmlui/handle/10214/16929

► Phytoglycogen is a glucose polymer that occurs naturally in the form of highly branched, compact nanoparticles. Because of their tree-like or dendrimeric structure, phytoglycogen nanoparticles… (more)

Subjects/Keywords: physics; biophysics; surface plasmon resonance; concanavalin A; phytoglycogen; association constant; polymer; bioactive

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APA (6^th Edition):

Charlesworth, K. (2019). The Creation of a Phytoglycogen-Functionalized SPR Sensor Surface and the Binding of Concanavalin A to Phytoglycogen. (Masters Thesis). University of Guelph. Retrieved from https://atrium.lib.uoguelph.ca/xmlui/handle/10214/16929

Chicago Manual of Style (16^th Edition):

Charlesworth, Kathleen. “The Creation of a Phytoglycogen-Functionalized SPR Sensor Surface and the Binding of Concanavalin A to Phytoglycogen.” 2019. Masters Thesis, University of Guelph. Accessed January 19, 2021. https://atrium.lib.uoguelph.ca/xmlui/handle/10214/16929.

MLA Handbook (7^th Edition):

Charlesworth, Kathleen. “The Creation of a Phytoglycogen-Functionalized SPR Sensor Surface and the Binding of Concanavalin A to Phytoglycogen.” 2019. Web. 19 Jan 2021.

Vancouver:

Charlesworth K. The Creation of a Phytoglycogen-Functionalized SPR Sensor Surface and the Binding of Concanavalin A to Phytoglycogen. [Internet] [Masters thesis]. University of Guelph; 2019. [cited 2021 Jan 19]. Available from: https://atrium.lib.uoguelph.ca/xmlui/handle/10214/16929.

Council of Science Editors:

Charlesworth K. The Creation of a Phytoglycogen-Functionalized SPR Sensor Surface and the Binding of Concanavalin A to Phytoglycogen. [Masters Thesis]. University of Guelph; 2019. Available from: https://atrium.lib.uoguelph.ca/xmlui/handle/10214/16929

15. Rahman, Luna. The Role of Intrinsically Disordered Thellungiella salsuginea dehydrins TsDHN-1 and TsDHN-2 in Stabilization of Membranes and Cytoskeletal Actin Filaments.

Degree: PhD, Department of Molecular and Cellular Biology, 2012, University of Guelph

URL: https://atrium.lib.uoguelph.ca/xmlui/handle/10214/3624

► The group 2 late embryogenesis abundant (LEA) proteins, also known as the dehydrins, are intrinsically disordered proteins that are expressed in plants experiencing extreme environmental… (more)

▼ The group 2 late embryogenesis abundant (LEA) proteins, also known as the dehydrins, are intrinsically disordered proteins that are expressed in plants experiencing extreme environmental conditions such as drought or low temperature. In this work, we study the potential roles that dehydrins may have in stabilizing membranes and actin microfilaments during cold stress. We have cloned and expressed in E. coli two dehydrins from Thellungiella salsuginea, denoted TsDHN-1 (acidic) and TsDHN-2 (basic). These proteins were expressed as SUMO-fusion proteins for in vitro phosphorylation by casein kinase II (CKII), and for structural analysis by CD and Fourier transform infrared (FTIR) spectroscopy. We show using transmission-FTIR spectroscopy that ordered secondary structure is induced and stabilized in these proteins by association with large unilamellar vesicles emulating the lipid compositions of plant plasma and organellar membranes. The increase in secondary structure by membrane association is further facilitated by the presence of Zn2+. Lipid composition and temperature have synergistic effects on the secondary structure. Our single molecule force spectroscopy studies also suggest tertiary folding of both TsDHN-1 and TsDHN-2 induced by association with lipids. From Langmuir-Blodgett monolayer compression studies, and from topographic studies using atomic force microscopy at variable temperature, we conclude that TsDHN-1 stabilizes the membrane at lower temperatures. Finally, we show that the conformations of TsDHN-1 and TsDHN-2 are affected by pH, interactions with cations and membranes, and phosphorylation. Actin assembly by these dehydrins was assessed by sedimentation assays, and viewed by transmission electron and atomic force microscopy. Phosphorylation enabled both dehydrins to polymerize actin filaments, a phenomenon that may occur in the cytosols of plant cells undergoing environmental stress. These results support the hypothesis that dehydrins stabilize plant organellar membranes and/or the cytoskeleton in conditions of stress, and further that phosphorylation may be an important feature of this stabilization. Advisors/Committee Members: Harauz, George (advisor), Dutcher, John (advisor).

Subjects/Keywords: dehydrins; late embryogenesis abundant (LEA); cold tolerance; Drought tolerance; intrinsically disordered protein (IDP); induced folding; Poly-proline type II; CD spectroscopy; FTIR spectroscopy; ATR-FTIR spectroscopy; peripheral membrane protein; Langmuir-Blodgett monolayers; supported lipid bilayers; atomic force microscopy; single molecule force spectroscopy; phosphorylation; actin polymerization

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

APA (6^th Edition):

Rahman, L. (2012). The Role of Intrinsically Disordered Thellungiella salsuginea dehydrins TsDHN-1 and TsDHN-2 in Stabilization of Membranes and Cytoskeletal Actin Filaments. (Doctoral Dissertation). University of Guelph. Retrieved from https://atrium.lib.uoguelph.ca/xmlui/handle/10214/3624

Chicago Manual of Style (16^th Edition):

Rahman, Luna. “The Role of Intrinsically Disordered Thellungiella salsuginea dehydrins TsDHN-1 and TsDHN-2 in Stabilization of Membranes and Cytoskeletal Actin Filaments.” 2012. Doctoral Dissertation, University of Guelph. Accessed January 19, 2021. https://atrium.lib.uoguelph.ca/xmlui/handle/10214/3624.

MLA Handbook (7^th Edition):

Rahman, Luna. “The Role of Intrinsically Disordered Thellungiella salsuginea dehydrins TsDHN-1 and TsDHN-2 in Stabilization of Membranes and Cytoskeletal Actin Filaments.” 2012. Web. 19 Jan 2021.

Vancouver:

Rahman L. The Role of Intrinsically Disordered Thellungiella salsuginea dehydrins TsDHN-1 and TsDHN-2 in Stabilization of Membranes and Cytoskeletal Actin Filaments. [Internet] [Doctoral dissertation]. University of Guelph; 2012. [cited 2021 Jan 19]. Available from: https://atrium.lib.uoguelph.ca/xmlui/handle/10214/3624.

Council of Science Editors:

Rahman L. The Role of Intrinsically Disordered Thellungiella salsuginea dehydrins TsDHN-1 and TsDHN-2 in Stabilization of Membranes and Cytoskeletal Actin Filaments. [Doctoral Dissertation]. University of Guelph; 2012. Available from: https://atrium.lib.uoguelph.ca/xmlui/handle/10214/3624

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