Engineering Commons^™

Nanosecond Pulsed Electric Fields Increase Antibiotic Susceptibility In Methicillin-Resistant Staphylococcus Aureus, Alexandra E. Chittams-Miles, Areej Malik, Erin B. Purcell, Claudia Muratori

Bioelectrics Publications

Staphylococcus aureus is the leading cause of skin and soft-tissue infections (SSTIs). SSTIs caused by bacteria resistant to antimicrobials, such as methicillin-resistant S. aureus (MRSA), are increasing in incidence and have led to higher rates of hospitalization. In this study, we measured MRSA inactivation by nanosecond pulsed electric fields (nsPEF), a promising new cell ablation technology. Our results show that treatment with 120 pulses of 600 ns duration (28 kV/cm, 1 Hz), caused modest inactivation, indicating cellular damage. We anticipated that the perturbation created by nsPEF could increase antibiotic efficacy if nsPEF were applied as a co-treatment. To test this …

Reducing Food Scarcity: The Benefits Of Urban Farming, S.A. Claudell, Emilio Mejia

Journal of Nonprofit Innovation

Urban farming can enhance the lives of communities and help reduce food scarcity. This paper presents a conceptual prototype of an efficient urban farming community that can be scaled for a single apartment building or an entire community across all global geoeconomics regions, including densely populated cities and rural, developing towns and communities. When deployed in coordination with smart crop choices, local farm support, and efficient transportation then the result isn’t just sustainability, but also increasing fresh produce accessibility, optimizing nutritional value, eliminating the use of ‘forever chemicals’, reducing transportation costs, and fostering global environmental benefits.

Imagine Doris, who is …

The Discovery, Characterization, And Engineering Of Autolytic Enzymes As Antimicrobials, Jacob M. Furlon

Dartmouth College Ph.D Dissertations

In an age of rising levels of antibiotic resistance, we are quickly running out of tools to address some of the most virulent and widespread infectious bacteria. One group of enzymes that show significant potential for use as next-generation antibiotics are antimicrobial peptidoglycan hydrolases, often referred to as lysins. These enzymes are responsible for the breakdown of peptidoglycan within the bacterial cell wall, and, when exogenously applied, can result in dramatic destabilization of the cell wall leading to rapid lysis of the bacteria. While phage endolysins have been widely investigated as potential antimicrobials, the therapeutic potential of endogenous autolysins from …

Analyzing Pseudomonas Aeruginosa With Bacteriophage Tags Using Photoacoustic Flow Cytometry, Jennifer C. Schinke

Electronic Theses and Dissertations

The number of daily bacterial infections is climbing and the CDC explains that this is due to the antibiotic-resistant threat in the United States. Finding a faster way of bacterial identification is necessary as it currently takes 1-4 days for a medical lab to culture and identify bacteria. Photoacoustic flow cytometry (PAFC) can be used as an alternative method resulting in swift identification within an hour (Edgar, 2019). Pseudomonas aeruginosa, cell line PA01, will be coated in up to a few hundred red dyed phages making it detectible by the photoacoustic flow cytometry system. Bacteriophages (phages) are viruses that …

Thermo-Responsive Antibiotic-Eluting Coatings For Treating Infection Near Orthopedic Implants, Jan Chung Kwan

Electronic Thesis and Dissertation Repository

The clinical effectiveness of orthopedic devices to restore the function of joints has been well established yet there is a lack of development in associated infections. As the demand for orthopedic surgeries continues to rise, infection remains a growing problem and one of the main reasons for revision surgeries. Bacterial contamination of the surgical site followed by adhesion of bacteria onto the surface of orthopedic devices leads to the formation of a biofilm which is a common initiator for infection. As a result, infection in the orthopedic field is commonly defined as orthopedic device-related infections (ODRI). There are limited options …

An Antimicrobial Polydopamine Surface Coating To Reduce Biofouling On Telemetry Tags Used In Marine Conservation Practices, Ariana Smies

Dissertations, Master's Theses and Master's Reports

Satellite telemetry tags are used to track the migration patterns of large cetaceans. These tags penetrate the dermis and remain embedded in the underlying blubber tissue. As the dermis of cetaceans is host to a diverse microbiome, and it is impossible to clean the skin before implanting the devices, the potential for infection is increased when the tags penetrate through the skin. H₂O₂ is a potential antimicrobial agent that, in addition to showing broad-spectrum efficacy against gram-negative and gram-positive bacteria, can promote wound healing outcomes by promoting proliferative factors and peptides that protect against oxidative stress. However, …

3d Printing Of Human Microbiome Constituents To Understand Spatial Relationships And Shape Parameters In Bacteriology, Jacques Izard, Teklu Kuru Gerbaba, Shara R. P. Yumul

Department of Food Science and Technology: Faculty Publications

Effective laboratory and classroom demonstration of microbiome size and shape, diversity, and ecological relationships is hampered by a lack of high-resolution, easy-to-use, readily accessible physical or digital models for use in teaching. Three-dimensional (3D) representations are, overall, more effective in communicating visuospatial information, allowing for a better understanding of concepts not directly observable with the unaided eye. Published morphology descriptions and microscopy images were used as the basis for designing 3D digital models, scaled at 20,000×, using computer-aided design software (CAD) and generating printed models of bacteria on mass-market 3D printers. Sixteen models are presented, including rod-shaped, spiral, flask-like, vibroid, …

Scalable Profiling And Visualization For Characterizing Microbiomes, Camilo Valdes

FIU Electronic Theses and Dissertations

Metagenomics is the study of the combined genetic material found in microbiome samples, and it serves as an instrument for studying microbial communities, their biodiversities, and the relationships to their host environments. Creating, interpreting, and understanding microbial community profiles produced from microbiome samples is a challenging task as it requires large computational resources along with innovative techniques to process and analyze datasets that can contain terabytes of information.

The community profiles are critical because they provide information about what microorganisms are present in the sample, and in what proportions. This is particularly important as many human diseases and environmental disasters …

Effects Of Ambient And Laser Light On Water Evaporation From The Surface Of Polyurethane Swabs Doped With Surfactant, Collin Campbell

Chemical Engineering Undergraduate Honors Theses

Polyurethane swabs are a common instrument for environmental sampling in the food, medical, and forensic fields due to their high recovery of organisms like viruses, spores, and bacteria. For sampling microbes in food and medical facilities, storage of the collected samples occurs under the absence of light to promote growth for more accurate testing. In the forensic fields, microbial growth results in sample contamination so the inhibition of this growth requires the drying of the swabs. This work studies the evaporation rates of water from polyurethane swabs under zero watt incident light, 30 W fluorescent bulb, 50 mW 532 nm …

Reducing Biomass Recalcitrance By Heterologous Expression Of A Bacterial Peroxidase In Tobacco (Nicotiana Benthamiana), Ayalew Ligaba-Osena, Bertrand Hankoua, Kay Dimarco, Robert Pace, Mark Crocker, Jesse Mcatee, Nivedita Nagachar, Ming Tien, Tom L. Richard

Center for Applied Energy Research Faculty and Staff Publications

Commercial scale production of biofuels from lignocellulosic feed stocks has been hampered by the resistance of plant cell walls to enzymatic conversion, primarily owing to lignin. This study investigated whether DypB, the lignin-degrading peroxidase from Rodococcus jostii, depolymerizes lignin and reduces recalcitrance in transgenic tobacco (Nicotiana benthamiana). The protein was targeted to the cytosol or the ER using ER-targeting and retention signal peptides. For each construct, five independent transgenic lines were characterized phenotypically and genotypically. Our findings reveal that expression of DypB in the cytosol and ER does not affect plant development. ER-targeting increased protein accumulation, and …

Graphene Oxide Quantum Dots Covalently Functionalized Pvdf Membrane With Significantly-Enhanced Bactericidal And Antibiofouling Performances, Zhiping Zeng, Dingshan Yu, Ziming He, Jing Liu, Fang-Xing Xiao, Yan Zhang, Rong Wang, Dibakar Bhattacharyya, Timothy Thatt Yang Tan

Chemical and Materials Engineering Faculty Publications

Covalent bonding of graphene oxide quantum dots (GOQDs) onto amino modified polyvinylidene fluoride (PVDF) membrane has generated a new type of nano-carbon functionalized membrane with significantly enhanced antibacterial and antibiofouling properties. A continuous filtration test using E. coli containing feedwater shows that the relative flux drop over GOQDs modified PVDF is 23%, which is significantly lower than those over pristine PVDF (86%) and GO-sheet modified PVDF (62%) after 10 h of filtration. The presence of GOQD coating layer effectively inactivates E. coli and S. aureus cells, and prevents the biofilm formation on the membrane surface, producing excellent antimicrobial activity and …

Inhibition Of Bacterial Growth And Prevention Of Bacterial Adhesion With Localized Nitric Oxide Delivery, Julia Osborne

Dissertations, Master's Theses and Master's Reports

Bacterial infections continue to be a problem at the site of an indwelling medical device, and over the years, various bacterial strains have become more resistant to current antibiotic treatments. Bacterial infection at an indwelling medical device can be dangerous and affect the performance of the medical device which can ultimately lead to the failure of the device due to bacterial resistance to treatment.

Nitric Oxide (NO) has been shown to possess antibacterial properties to prevent and inhibit bacterial growth. NO releasing coatings on indwelling medical devices could provide a reduction in bacterial infections that occur at the device site …

First Proof Of Concept Of Sustainable Metabolite Production From High Solids Fermentation Of Lignocellulosic Biomass Using A Bacterial Co-Culture And Cycling Flush System, Wanying Yao, Sue E. Nokes

Biosystems and Agricultural Engineering Faculty Publications

To improve the lignocellulose conversion for ABE in high solids fermentation, this study explored the feasibility of cycling the process through the cellulolytic or/and solventogenic phases via intermittent flushing of the fermentation media. Five different flushing strategies (varying medium ingredients, inoculum supplement and cycling through phases) were investigated. Flushing regularly throughout the cellulolytic phase is necessary because re-incubation at 65 °C significantly improved glucose availability by at least 6-fold. The solvents accumulation was increased by 4-fold using corn stover (3-fold using miscanthus) over that produced by flushing only through the solventogenic phase. In addition, cycling process was simplified by re-incubating …

Phanerochaete Chrysosporium Pretreatment Of Biomass To Enhance Solvent Production In Subsequent Bacterial Solid-Substrate Cultivation, Wanying Yao, Sue E. Nokes

Biosystems and Agricultural Engineering Faculty Publications

This study investigated pretreatment of corn stover using solid substrate cultivation (SSC) of Phanerochaete chrysosporium (P. chrysosporium) to improve subsequent accessibility to cellulose. Thereafter, Clostridium thermocellum (C. thermocellum) was directly inoculated onto the pretreated biomass to accomplish hydrolysis, followed by solventogenesis by introducing Clostridium beijerinckii (C. beijerinckii).

An enzyme suite containing laccase, lignin peroxidase and manganese peroxidase activity was detected during the cultivation of P. chrysosporium on corn stover within 288 h at an initial moisture content 𝓌_H2O = 80% (mass of water/total mass). Incubation factors, such as substrate moisture content and cultivation …

Development Of Pyrf-Based Genetic System For Targeted Gene Deletion In Clostridium Thermocellum And Creation Of A Pta Mutant, Shital A. Tripathi, Daniel G. Olson, D. Aaron Argyros, Bethany B. Miller, Trisha F. Barrett, Daniel M. Murphy, Jesse D. Mccool, Anne K. Warner, Vineet B. Rajgarhia, Lee R. Lynd, David A. Hogsett, Nicky C. Caiazza

Dartmouth Scholarship

We report development of a genetic system for making targeted gene knockouts in Clostridium thermocellum, a thermophilic anaerobic bacterium that rapidly solubilizes cellulose. A toxic uracil analog, 5-fluoroorotic acid (5-FOA), was used to select for deletion of the pyrF gene. The ΔpyrF strain is a uracil auxotroph that could be restored to a prototroph via ectopic expression of pyrF from a plasmid, providing a positive genetic selection. Furthermore, 5-FOA was used to select against plasmid-expressed pyrF, creating a negative selection for plasmid loss. This technology was used to delete a gene involved in organic acid production, namely pta, which encodes …

Indicator Bacteria Concentrations Of Two Northwest Arkansas Streams In Relation To Flow And Season, Dwayne R. Edwards, Mark S. Coyne, Tommy C. Daniel, P. F. Vendrell, J. F. Murdoch, P. A. Moore Jr.

Biosystems and Agricultural Engineering Faculty Publications

Concentrations of indicator bacteria such as fecal coliform (FC) and fecal streptococcus (FS) are often used to assess the suitability of waters for their intended use(s) and to allocate resources for water quality improvement measures. There is evidence, however, that concentrations of FC and FS can be influenced by variables such as season and flow rate during sampling, which could lead to biased results. The objective of this study was to assess the impacts of season and flow rate on concentrations of FC and FS. Fecal indicator bacteria concentrations were measured for approximately three years at five sites on two …