Identification of Polymethylene-Interrupted Polyunsaturated Fatty Acids (PMI-PUFA) by Solvent-Mediated Covalent Adduct Chemical Ionization Triple Quadrupole Tandem Mass Spectrometry.

Pine nuts and other edible gymnosperm seeds contain unusual, bioactive polymethylene-interrupted polyunsaturated fatty acids (PMI-PUFAs), a subset of nonmethylene-interrupted PUFA with (-CH2-)n≥2 intervening between double bonds. Conventional methods for structure elucidation of PMI-PUFAs require special derivatization risking rearrangement artifacts. Here we introduce a facile solvent-mediated (SM) covalent adduct chemical ionization (CACI) system modified with a triple quadrupole MS, which distinguishes PMI-PUFAs from their analogues in direct methyl ester form. The prominent Δ5 desaturated PMI-PUFAs exhibit characteristic fragmentation at C6-7 to yield ω diagnostic ions and share their fragmentation pattern with normal methylene interrupted PUFAs for the α diagnostic ion. H• transfer upon CID dissociation of PMI-PUFAs was found to be dependent on the relative position of isolated lone double bonds and cleavage points. Ginkgo and five species of pine nuts were characterized for their unique Δ5 fatty acid profile, without the need for chemical standards.

Tyrosine-derived polymeric surfactant nanospheres insert cholesterol in cell membranes.

HYPOTHESIS: The design of biodegradable tyrosine-derived polymeric surfactants (TyPS) through the use of calculated thermodynamic parameters could lead to phospholipid membrane surface modifiers capable of controlling cellular properties such as viability. Delivery of cholesterol by TyPS nanospheres into membrane phospholipid domains could provide further controlled modulation of membrane physical and biological properties. EXPERIMENT: Calculated Hansen solubility parameters (∂T) and hydrophile:lipophile balances (HLB) were applied to design and synthesize a small family of diblock and triblock TyPS with different hydrophobic blocks and PEG hydrophilic blocks. Self-assembled TyPS/cholesterol nanospheres were prepared in aqueous media via co-precipitation. Cholesterol loading and Langmuir film balance surface pressures of phospholipid monolayers were obtained. TyPS and TyPS/cholesterol nanosphere effects on human dermal cell viability were evaluated by cell culture using poly(ethylene glycol) (PEG) and Poloxamer 188 as controls. FINDINGS: Stable TyPS nanospheres incorporated between 1% and 5% cholesterol. Triblock TyPS formed nanosphere with dimensions significantly smaller than diblock TyPS nanospheres. In accord calculated thermodynamic parameters, cholesterol binding increased with increasing TyPS hydrophobicity. TyPS inserted into phospholipid monolayer films in a manner consistent with their thermodynamic properties and TyPS/cholesterol nanospheres delivered cholesterol into the films. Triblock TyPS/cholesterol nanospheres increased human dermal cell viability, which was indicative of potentially beneficial TyPS effects on cell membrane surface properties.

Case report: analysis of an ultra-high-molecular-weight polyethylene acetabular cup retrieval at 41 years.

A polyethylene cup explanted after 41 years was examined using several analytical techniques to determine whether there was a material cause for the extremely low wear observed. Neither the amount of polyethylene oxidation nor crystallinity appeared to be a factor.

Potentially High Value Conjugated Linolenic Acids (CLnA) in Melon Seed Waste.

Conjugated linolenic acids (CLnAs) are natural phytochemicals with known and potential bioactivities in mammals. Established CLnA sources are limited to a few common fruit seeds, notably pomegranate seeds and cherry pits, and the search for alternatives is impeded in part by cumbersome methods for reliable measurement. We investigated CLnA contents in lower value fruit seeds with a recently available facile mass spectrometry method, solvent-mediated chemical ionization, enabling and quantitative analysis. We report for the first time the detection of CLnAs in cantaloupe and honeydew seeds at levels of 2 mg CLnA/g seed kernel. Based on the combined waste stream for these muskmelons of about 1.4 billion pounds in the USA annually, we estimate that the available CLnAs amount to 37.5 tons, similar to cherry pits. Our results suggest the potentially enhanced economic value of a specific class of bioactives that may be extracted from discarded food processing waste.

Isobaric tags for relative and absolute quantitation-based proteome analysis of Vietnamese colorectal carcinoma tissues.

CONTEXT: Colorectal cancer (CRC) is one of the most common malignancies and one of the leading causes of cancer death worldwide. Establishing early detection methods or markers of CRC is central to improve the survival rate of CRC patients. Nowadays, new molecular tools have been developed to acquire further knowledge on tumor progression. AIMS: Comparative proteomics analysis of Vietnamese colorectal carcinoma in different stages was performed to gain an insight into the molecular events taking place in CRC and metastasis. SUBJECTS AND METHODS: In this study, the comparative protein expression analysis of ten paired CRC and its corresponding noncancerous tissue samples was performed using the combination of isobaric tags for relative and absolute quantitation labeling and mass spectrometry (MS). The data obtained were further analyzed with Ingenuity Pathways Analysis (IPA) system. RESULTS: Based on the MS/MS spectra analyzed by ProteinPilot software, 684 proteins were identified, out of which 215 were observed to be differentially expressed in at least 1 sample pair. Individual protein expression and variation have been identified for each patient. IPA system demonstrated cytoskeletal signaling as the top-ranked functional pathway network associated with the oncogenic function. CONCLUSIONS: Our study supplemented the understanding about proteome of Vietnamese CRC patients and identified statistically protein expression differences among samples assisting in finding effective biomarkers for CRC diagnostics.

iTRAQ-based proteome analysis of fluoroquinolone-resistant Staphylococcus aureus.

OBJECTIVES: The aim of this study was to compare global protein expression changes during fluoroquinolone (FQ) exposure of Staphylococcus aureus. METHODS: Total protein extracts of wild-type S. aureus ATCC 29213 and six multidrug-resistant (MDR) strains derived from the wild-type under different FQ exposures were analysed using the 8-plex isobaric tag for relative and absolute quantitation (iTRAQ) method combined with LC-MS/MS analysis. Differentially expressed proteins were searched for their Gene Ontology (GO) annotation (UniProt database) and protein-protein interaction network (STRING v.10.0). recA expression was determined by real-time quantitative reverse transcription PCR (qRT-PCR) analysis. RESULTS: Overall, 582 unique proteins were identified at a confidence level of >95% (unused cut-off >1.3). After strict filtering for proteins with significant expression changes in comparison with the wild-type S. aureus ATCC 29213, 147 unique proteins were identified. GO searching showed that development of FQ resistance was associated with altered expression of various proteins involved in the SOS response (RecA), antibiotic resistance (MgrA), pathogenesis (uncharacterised leukocidin-like proteins 1 and 2, immunoglobulin-binding protein Sbi, triosephosphate isomerase, enolase, EsxA, SaeR, SarA, MgrA) and the stress response (alkyl hydroperoxide reductase subunit C, ClpB, ClpC, ClpL, ClpX, HslU, l-lactate dehydrogenase 1 and 2, SAV1710). Network analysis of antibiotic resistance-related proteins identified three major protein clusters involved in metabolic pathways, aminoacyl-tRNA biosynthesis and ribosome structure. qRT-PCR results were consistent with the proteomics data. CONCLUSIONS: Development of resistance to multiple drugs, including FQs, under drug exposure mostly involves upregulation of SOS and stress response proteins.

Multiphase blends from poly(L-lactide) and poly(methyl mathacrylate).

Melt processing of poly(L-lactide) (PLLA) and poly(methyl methacrylate) (PMMA) was conducted over a targeted range of compositions with PLLAs of 118 and 316 kDa in molecular mass to identify morphologies and the phase relationships in these blends. These blends are of interest for use in biomaterials and the morphologies are critical for tissue-engineering studies where biodegradability, pore connectivity and surface texture control tissue viability and adhesion. Simple extrusion of the two polymers produced multiphase blends with an average domain size near 25 microm. Scanning electron microscopy and dynamic mechanical analysis demonstrated that these blends are immiscible, at least in a metastable sense, and regions of co-continuous structures were identified. Such co-continuous, which occurred generally in accordance with rheology prediction models, exhibit a fine interconnected structure that appears effective for fabricating certain biomaterials. A broad and unexpected transition appears in these blends, as measured by modulated differential scanning calorimetry between 70 and 100 degrees C, which may be the glass transition temperature of an alloy phase. The magnitude of this transition is greatest in the fine-structured co-continuous composition region of blends, suggesting the presence of a complex or other derivative of the two primary phases.