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Development And Evaluation Of Novel Vaccination Strategies For Campylobacter Control In Poultry, Xiang Liu

Masters Theses

Chicken is the primary natural host of Campylobacter, the leading bacterial cause of human enteritis in the US and other developed countries. Thus, mitigation of Campylobacter in chicken using innovative approaches, such as vaccination, will have a significant impact on food safety and public health. Our previous studies have demonstrated that the two outer membrane proteins, CmeC (the essential component of the CmeABC multi-drug efflux pump) and CfrA (a ferric enterobactin receptor), are feasible candidates for immune intervention against Campylobacter. DNA vaccine has appeared to offer various advantages for poultry, particularly when combined with in ovo vaccination. Chitosan-encapsulated …

Gallic Acid-Grafted Chitosan Films As Antioxidant Food Packaging, Ping Guo

Masters Theses

Chitosan is the second most abundant natural polysaccharide in the nature. Due to its biodegradability and film forming ability, chitosan has the potential to be used as an alternative to petroleum-based polymers for food packaging. The presence of a primary amine as well as primary and secondary hydroxyl groups enable chitosan to be chemically modified with various functional groups. Gallic acid (GA) is a natural occurring antioxidant (AOX), which can be grafted to chitosan using by 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC) and N-hydroxysuccinimide (NHS). The first project deals with the effect of ethanol (EtOH) concentration on efficiency of grafting GA onto chitosan. …

Characterization Of Genes And Pathways Controlling Biofilm Formation In Saccharomyces Cerevisiae, Neha Sarode

Doctoral Dissertations

Biofilms are a mode of growth where aggregated cells adhere to a foreign surface and grow as a complex community. Biofilms have found wide utility in commercial industries, however infections caused by biofilms in clinical settings are a major cause of concern. Understanding molecular details of biofilm formation could help in exploitation or elimination efforts.

We utilize Saccharomyces cerevisiae as a model system to study biofilm formation. S. cerevisiae strain belonging to genetic background Σ [sigma] 1278b is capable of forming biofilms, on low density (0.3%) agar media. When grown at 25°[degree] C for 5 days, it develops into an …

Chitosan-Gallic Acid Films As Multifunctional Food Packaging, Stephanie Beth Schreiber

Masters Theses

Chitosan is a good candidate for multifunctional food packaging because of its biocompatibility, biodegradability, antibacterial properties, secondary antioxidant activity, film forming ability, resistance to lipids and because of its structure which is very desirable for grafting various compounds to it. For this research, we took advantage of chitosan’s amino group that has nuceleophilic character at a pH above its pKa, which is 6.3. Gallic acid, a phenolic compound with primary antioxidant properties was grafted to chitosan using 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide and N-hydroxysuccinimide. Grafting was evaluated using FTIR-ATR and ¹H and ¹³CNMR. FTIR showed evidence of grafting on the amino …

Effectiveness Of Different Molecular Weights And Concentrations Of Chitosan On Enteric Viral Surrogates, Robert Hamilton Davis

Masters Theses

Chitosan is known to be antibacterial and antifungal, but information on its effectiveness against foodborne viruses is limited. Enteric viruses are a major concern in food safety, especially human noroviruses which are the leading cause of nonbacterial gastroenteritis. The overall goal of this research was to determine the antiviral effectiveness of chitosan. The specific objectives were to determine the effects of molecular weight (MW) and concentration of chitosan against the cultivable enteric viral surrogates, feline calicivirus (FCV-F9), murine norovirus (MNV-1), and bacteriophages (MS2 and phiX174). Purified chitosans (53, 222, 307, 421, ~1,150kDa) were dissolved in water, 1% acetic acid, or …

Depolymerization Of Chitosan By High-Pressure Homogenization And The Effect On Antimicrobial Properties, Deidra Shannon Lyons

Masters Theses

The focus of this study was to look at relationship between polydispersity caused by high pressure homogenization and molecular weight dependent antimicrobial activity of chitosan. It has been shown that chitosan has antimicrobial activity against bacteria, fungi, and viruses. Chitosan is obtained by partial de-N-acetylation of chitin which, consists of a ß 1-4 copolymer of glucosamine and N-acetylglucosamine residues. In this experiment we compared chitosan of sixteen different molecular weights after being processed through a high pressure homogenizer. Processed chitosan (420 kDa average molecular weight, 30% of acetylation) was dissolved in a 1% (v/v) acetic acid in water to a …

Physical Characteristics And Metal Binding Applications Of Chitosan Films, Joshua B. Jones

Masters Theses

Chitosan films are an excellent media for binding metal ions due to the electrostatic nature of the chitosan molecules. Addition of cross-linking or plasticizing agents alters texture of the films, but their effect on metal-binding capacity has not been fully characterized. The objective of this research was to determine effects of plasticizers and cross-linkers on physical and metal-binding properties of chitosan films and coatings prepared by casting and by spincoating. Chitosan films were prepared using 1% w/w chitosan in 1% acetic acid with or without (control) additives. Plasticizing agents were tetraethylene glycol (TEG) and glycerol while citric acid, ethylenediamine tetraacetic …

Developing Chitosan-Based Biomaterials For Brain Repair And Neuroprosthetics, Zheng Cao

Masters Theses

Chitosan is widely investigated for biomedical applications due to its excellent properties, such as biocompatibility, biodegradability, bioadhesivity, antibacterial, etc. In the field of neural engineering, it has been extensively studied in forms of film and hydrogel, and has been used as scaffolds for nerve regeneration in the peripheral nervous system and spinal cord. One of the main issues in neural engineering is the incapability of neuron to attach on biomaterials. The present study, from a new aspect, aims to take advantage of the bio-adhesive property of chitosan to develop chitosan-based materials for neural engineering, specifically in the fields of brain …

Development And Characterization Of Antimicrobial Food Coatings Based On Chitosan And Essential Oils, Shuang Chi

Masters Theses

The objectives of this research were (1) to evaluate antimicrobial effects of essential oils incorporated in chitosan edible films against Listeria monocytogenes and Escherichia coli O157:H7, (2) to evaluate effectiveness of the films on a meat product, (3) to characterize physical properties of chitosan films enriched with essential oils, and (4) to determine whether the addition of oregano essential oil to bologna can influence consumer liking of the product.

Anise, basil, coriander, and oregano essential oils were tested for antimicrobial activity by paper disc diffusion test with concentration of 1 to 24 ml/disc. Chitosan films incorporated with those essential oils …