Characterization of nanoparticles in silicon dioxide food additive.

Silicon dioxide (SiO), in its amorphous form, is an approved direct food additive in the United States and has been used as an anticaking agent in powdered food products and as a stabilizer in the production of beer. While SiO has been used in food for many years, there is limited information regarding its particle size and size distribution. In recent years, the use of SiO food additive has raised attention because of the possible presence of nanoparticles.

The Utility of Genomic and Transcriptomic Data in the Construction of Proxy Protein Sequence Databases for Unsequenced Tree Nuts.

As the apparent incidence of tree nut allergies rises, the development of MS methods that accurately identify tree nuts in food is critical. However, analyses are limited by few available tree nut protein sequences. We assess the utility of translated genomic and transcriptomic data for library construction with , walnut, as a model.

Screening of Processed Foods for Transgenic Proteins from Genetically Engineered Plants Using Targeted Mass Spectrometry.

Screening of food products for the presence of material from genetically engineered (GE) plants is typically done using deoxyribonucleic acid (DNA)-based methods to detect the presence of transgenic DNA. In this study, we have demonstrated the feasibility of using targeted mass spectrometry (MS) to detect a protein expressed by transgenic DNA to confirm the presence of GE plant material in processed foods. Scheduled parallel reaction monitoring (sPRM) was used to detect the enzyme, 5-enolpyruvulshikimate-3-phosphate synthase, from .

Influences of simulated gastrointestinal environment on physicochemical properties of gold nanoparticles and their implications on intestinal epithelial permeability.

Gold nanoparticles (Au NPs) hold great promise in food, industrial and biomedical applications due to their unique physicochemical properties. However, influences of the gastrointestinal tract (GIT), a likely route for Au NPs administration, on the physicochemical properties of Au NPs has been rarely evaluated. Here, we investigated the influence of GIT fluids on the physicochemical properties of Au NPs (5, 50, and 100 nm) and their implications on intestinal epithelial permeability .

Ferroxidase-like and antibacterial activity of PtCu alloy nanoparticles.

Many metal nanoparticles are reported to have intrinsic enzyme-like activities and offer great potential in chemical and biomedical applications. In this study, PtCu alloy nanoparticles (NPs), synthesized through hydrothermal treatment of Cu and Pt in an aqueous solution, were evaluated for ferroxidase-like and antibacterial activity. Electron spin resonance (ESR) spectroscopy and colorimetric methods were used to demonstrate that PtCu NPs exhibited strong ferroxidase-like activity in a weakly acidic environment and that this activity was not affected by the presence of most other ions, except silver.

Optimized chemical coverage and data quality for non-targeted screening applications using liquid chromatography/high-resolution mass spectrometry.

Non-targeted small molecule screening methods are used to analyze samples for potential compounds of interest without focusing on specific molecular species. There is great interest in these methods for metabolomic, environmental, forensic, and food safety applications, among others, to determine compounds that are responsible for a particular disease state or the presence of a harmful compound. In order for non-targeted analyses to become standardized and routine, best practices for sample preparation, data collection, and data analysis must be determined.

Identification of Salmonella Taxon-Specific Peptide Markers to the Serovar Level by Mass Spectrometry.

We present an LC-MS/MS pipeline to identify taxon-specific tryptic peptide markers for the identification of Salmonella at the genus, species, subspecies, and serovar levels of specificity. Salmonella enterica subsp. enterica serovars Typhimurium and its four closest relatives, Saintpaul, Heidelberg, Paratyphi B, and Muenchen, were evaluated.

Platinum nanoparticles: an avenue for enhancing the release of nitric oxide from S-nitroso-N-acetylpenicillamine and S-nitrosoglutathione.

Nitric oxide (NO) is an endogenous bioregulator with established roles in diverse fields. The difficulty in the modulation of NO release is still a significant obstacle to achieving successful clinical applications. We report herein our initial work using electron spin resonance (ESR) spectroscopy to detect NO generated from S-nitroso-N-acetylpenicillamine (SNAP) and S-nitrosoglutathione (GSNO) donors catalyzed by platinum nanoparticles (Pt NPs, 3 nm) under physiological conditions.

Effects of noble metal nanoparticles on the hydroxyl radical scavenging ability of dietary antioxidants.

Noble metal nanoparticles (NPs) have been widely used in many consumer products. Their effects on the antioxidant activity of commercial dietary supplements have not been well evaluated. In this study, we examined the effects of gold (Au NPs), silver (Ag NPs), platinum (Pt NPs), and palladium (Pd NPs) on the hydroxyl radical (·OH) scavenging ability of three dietary supplements vitamin C (L-ascorbic acid, AA), (-)-epigallocatechin gallate (EGCG), and gallic acid (GA).

Bactericidal Effects of Silver Nanoparticles on Lactobacilli and the Underlying Mechanism.

While the antibacterial properties of silver nanoparticles (AgNPs) have been demonstrated across a spectrum of bacterial pathogens, the effects of AgNPs on the beneficial bacteria are less clear. To address this issue, we compared the antibacterial activity of AgNPs against two beneficial lactobacilli ( Lactobacillus delbrueckii subsp. bulgaricus and Lactobacillus casei) and two common opportunistic pathogens ( Escherichia coli and Staphylococcus aureus).

Analysis of Gluten in a Wheat-Gluten-Incurred Sorghum Beer Brewed in the Presence of Proline Endopeptidase by LC/MS/MS.

Most gluten-reduced beers are produced using an enzyme called proline endopeptidase (PEP), which proteolyzes the gluten by cleaving at proline residues. However, the gluten content of beers brewed in the presence of PEP cannot be verified since current analytical methods are not able to accurately quantitate gluten in fermented foods. In this work, mass spectrometry was used to qualitatively characterize the gluten in a wheat-gluten-incurred sorghum model beer brewed with and without the addition of PEP.

Exploring the activities of ruthenium nanomaterials as reactive oxygen species scavengers.

Research on noble metal nanoparticles (NPs) able to scavenge reactive oxygen species (ROS) has undergone a tremendous growth recently. However, the interactions between ruthenium nanoparticles (Ru NPs) and ROS have never been systematically explored thus far. This research focused on the decomposition of hydrogen peroxide (HO), scavenging of hydroxyl radicals (OH), superoxide radical (O), singlet oxygen (O), 2,2'-azino-bis(3-ethylbenzenothiazoline- 6-sulfonic acid ion (ABTS), and 1,1-diphenyl-2-picrylhydrazyl radical (DPPH) in the presence of commercial Ru NPs using the electron spin resonance technique.

Effects of P25 TiO Nanoparticles on the Free Radical-Scavenging Ability of Antioxidants upon Their Exposure to Simulated Sunlight.

Although nanosized ingredients, including TiO nanoparticles (NPs), can be found in a wide range of consumer products, little is known about the effects these particles have on other active compounds in product matrices. These NPs can interact with reactive oxygen species (ROS), potentially disrupting or canceling the benefits expected from antioxidants. We used electron spin resonance spectrometry to assess changes in the antioxidant capacities of six dietary antioxidants (ascorbic acid, α-tocopherol, glutathione, cysteine, epicatechin, and epicatechin gallate) during exposure to P25 TiO and/or simulated sunlight.

Nontargeted Screening of Food Matrices: Development of a Chemometric Software Strategy To Identify Unknowns in Liquid Chromatography-Mass Spectrometry Data.

The ability to identify contaminants or adulterants in diverse, complex sample matrixes is necessary in food safety. Thus, nontargeted screening approaches must be implemented to detect and identify unexpected, unknown hazardous compounds that may be present. Molecular formulas can be generated for detected compounds from high-resolution mass spectrometry data, but analysis can be lengthy when thousands of compounds are detected in a single sample.

Rapid and sensitive detection of cholera toxin using gold nanoparticle-based simple colorimetric and dynamic light scattering assay.

Herein, a rapid and simple gold nanoparticle based colorimetric and dynamic light scattering (DLS) assay for the sensitive detection of cholera toxin has been developed. The developed assay is based on the distance dependent properties of gold nanoparticles which cause aggregation of antibody-conjugated gold nanoparticles in the presence of cholera toxin resulting discernible color change. This aggregation induced color change caused a red shift in the plasmon band of nanoparticles which was measured by UV-Vis spectroscopy.

Non-targeted screening approaches for contaminants and adulterants in food using liquid chromatography hyphenated to high resolution mass spectrometry.

The majority of analytical methods for food safety monitor the presence of a specific compound or defined set of compounds. Non-targeted screening methods are complementary to these approaches by detecting and identifying unexpected compounds present in food matrices that may be harmful to public health. However, the development and implementation of generalized non-targeted screening workflows are particularly challenging, especially for food matrices due to inherent sample complexity and diversity and a large analyte concentration range.

Identification and Structural Characterization of Naturally-Occurring Broad-Spectrum Cyclic Antibiotics Isolated from Paenibacillus.

The rise of antimicrobial resistance necessitates the discovery and/or production of novel antibiotics. Isolated strains of Paenibacillus alvei were previously shown to exhibit antimicrobial activity against a number of pathogens, such as E. coli, Salmonella, and methicillin-resistant Staphylococcus aureus (MRSA).

Mass accuracy and isotopic abundance measurements for HR-MS instrumentation: capabilities for non-targeted analyses.

The development of automated non-targeted workflows for small molecule analyses is highly desirable in many areas of research and diagnostics. Sufficient mass and chromatographic resolution is necessary for the detectability of compounds and subsequent componentization and interpretation of ions. The mass accuracy and relative isotopic abundance are critical in correct molecular formulae generation for unknown compounds.

Draft Genome Sequences of Two O104:H21 Escherichia coli Isolates Causing Hemorrhagic Colitis during a 1994 Montana Outbreak Provide Insight into Their Pathogenicity.

We sequenced the genomes of two strains of O104:H21 enterohemorrhagic Escherichia coli (EHEC) isolated during an outbreak of hemorrhagic colitis in Montana in 1994. These strains carried a plasmid that contains several virulence genes not present in pO157. The genome sequences will improve phylogenetic analysis of other non-O157 E.

Purification and characterization of neurotoxin complex from a dual toxin gene containing Clostridium Botulinum Strain PS-5.

Botulinum neurotoxins are produced as a toxin complex (TC) which consists of neurotoxin (NT) and neurotoxin associated proteins. The characterization of NT in its native state is an essential step for developing diagnostics and therapeutic countermeasures against botulism. The presence of NT genes was validated by PCR amplification of toxin specific fragments from genomic DNA of Clostridium botulinum strain PS-5 which indicated the presence of both serotype A and B genes on PS-5 genome.

A robust high-throughput sample preparation and liquid chromatography/tandem mass spectrometry method for the quantitation of β-lyase metabolites of sulfur mustard as 1,1'-sulfonylbis-[2-(methylthio)ethane] in human urine.

Rationale: Sulfur mustard (HD) is a major chemical warfare agent threat to humans. Since World War I, several incidents of human exposure to sulfur mustard have been reported. In order to assist health professionals during an exposure event and support biological monitoring, a rapid analytical method is required to measure the exposure of humans to HD.

The chromatographic role in high resolution mass spectrometry for non-targeted analysis.

Resolution improvements in time-of-flight instrumentation and the emergence of the Orbitrap mass spectrometer have researchers using high resolution mass spectrometry to determine elemental compositions and performing screening methods based on the full-scan data from these instruments. This work is focused on examining instrument performance of both a QTOF and a bench-top Orbitrap. In this study, the impact of chromatographic resolution on mass measurement accuracy, mass measurement precision, and ion suppression is examined at a fundamental level.

High-throughput sample preparation and simultaneous column regeneration liquid chromatography-tandem mass spectrometry method for determination of nitrogen mustard metabolites in human urine.

Nitrogen mustards (NMs) are known to have DNA alkylation and strong vesicant properties. Their availability to terrorist organizations makes them a potential choice for chemical attacks on civilian populations. After an exposure, it is difficult to measure NMs directly because of their rapid metabolism in the human body.