Removal Of Lipids Research Articles

Optimized method for the extraction of contaminant-free IgY antibodies from egg yolk using PEG 6000

Hens are oviparous vertebrates and produce IgY antibodies, which is the main type of immunoglobulin in the egg yolk, and high concentrations can be obtained by using a simple method that does not require sophisticated equipment and reagents. The Polyethylene Glycol 6000 method allows the removal of lipids and the precipitation of IgY in two days with an approximated purity of around 80%, however during the original protocol other contaminant proteins can be precipitated. To overcome the issue of contamination with other proteins and extraction time, we optimized the previously method described by Pauly et al. (2011) by adding some changes that improved the aforementioned problems.• Our protocol is customized by the addition of one more filtration step or one more step with PEG 6000 at 3.5% to avoid the contamination with lipids.• Additionally, the changes in the type of agitation, centrifugation and the skip of dialysis make the method more accessible for all the laboratories.• In summary, these modifications serve to enhance the purity, reduce the time for IgY extraction from egg yolk and make it more accessible for every basic research laboratory.

The effects of removing endogenous proteins, β-glucan and lipids on the surface microstructure, water migration and glucose diffusion in vitro of starch in highland barley flour

The effects of removing non-starch components on the surface microstructure, water migration and glucose diffusion rate of highland barley starch (HBS) were systematically studied to reveal the models that affect the digestibility of HBS. The results of scanning electron micrographs, confocal laser scanning microscopy, polarization cross and particle size distribution showed that there were two particle size ranges in highland barley flour, large (73.99–591.90 μm) and small (<73.99 μm). Partial β-glucan and proteins form a compact and continuous matrix on the surface of HBS granules; lipids can partly be adsorbed on the surface of HBS granules, while other lipids, proteins and β-glucan are scattered around HBS granules. After the removal of non-starch components, the ratio of large particles decreased and the starch granules were more exposed, especially proteins and β-glucan. The results of low-field nuclear magnetic resonance investigation showed that the water migration rate was accelerated after the removal of β-glucan, and partial free water was transformed into weakly bound water, while the opposite effect was observed for the removal of proteins and lipids. The glucose diffusion rate in vitro was unchanged after the removal of lipids, while the removal of β-glucan significantly accelerated the diffusion of glucose in vitro. This study reveals that the effective models of HBS inhibited by non-starch components is the compact matrix mainly formed by proteins and β-glucan on the surface of HBS granules. Additionally, the rate of glucose diffusion across the small intestinal wall could be considered as one of the means of constructing slowly digestible starch.

Fundamentals of Membrane Lipid Replacement: A Natural Medicine Approach to Repairing Cellular Membranes and Reducing Fatigue, Pain, and Other Symptoms While Restoring Function in Chronic Illnesses and Aging.

Membrane Lipid Replacement (MLR) uses natural membrane lipid supplements to safely replace damaged, oxidized lipids in membranes in order to restore membrane function, decrease symptoms and improve health. Oral MLR supplements contain mixtures of cell membrane glycerolphospholipids, fatty acids, and other lipids, and can be used to replace and remove damaged cellular and intracellular membrane lipids. Membrane injury, caused mainly by oxidative damage, occurs in essentially all chronic and acute medical conditions, including cancer and degenerative diseases, and in normal processes, such as aging and development. After ingestion, the protected MLR glycerolphospholipids and other lipids are dispersed, absorbed, and internalized in the small intestines, where they can be partitioned into circulating lipoproteins, globules, liposomes, micelles, membranes, and other carriers and transported in the lymphatics and blood circulation to tissues and cellular sites where they are taken in by cells and partitioned into various cellular membranes. Once inside cells, the glycerolphospholipids and other lipids are transferred to various intracellular membranes by lipid carriers, globules, liposomes, chylomicrons, or by direct membrane–membrane interactions. The entire process appears to be driven by ‘bulk flow’ or mass action principles, where surplus concentrations of replacement lipids can stimulate the natural exchange and removal of damaged membrane lipids while the replacement lipids undergo further enzymatic alterations. Clinical studies have demonstrated the advantages of MLR in restoring membrane and organelle function and reducing fatigue, pain, and other symptoms in chronic illness and aging patients.

Methods to reduce lipemic interference in clinical chemistry tests: a systematic review and recommendations.

Lipemia is the presence of abnormally high lipoprotein concentrations in serum or plasma samples that can interfere with laboratory testing. There is little guidance available from manufacturers or professional bodies on processing lipemic samples to produce clinically acceptable results. This systematic review summarizes existing literature on the effectiveness of lipid removal techniques in reducing interference in clinical chemistry tests. A PubMed search using terms relating to lipid removal from human samples for clinical chemistry tests produced 1,558 studies published between January 2010 and July 2021. 15 articles met the criteria for further analyses. A total of 66 analytes were investigated amongst the 15 studies, which showed highly heterogenous study designs. High-speed centrifugation was consistently effective for 13 analytes: albumin, alkaline phosphatase (ALP), alanine aminotransferase (ALT), aspartate aminotransferase (AST), total bilirubin, creatine kinase (CK), creatinine (Jaffe method), gamma-glutamyl transferase (GGT), glucose (hexokinase-based method), lactate dehydrogenase (LDH), phosphate, potassium, and urea. Lipid-clearing agents were uniformly effective for seven analytes: ALT, AST, total bilirubin, CK, creatinine (Jaffe method), lipase, and urea. Mixed results were reported for the remaining analytes. For some analytes, high-speed centrifugation and/or lipid-clearing agents can be used in place of ultracentrifugation. Harmonized protocols and acceptability criteria are required to allow pooled data analysis and interpretation of different lipemic interference studies.

Reduced Washing Cycle for Sustainable Mackerel (Rastrelliger kanagurta) Surimi Production: Evaluation of Bio-Physico-Chemical, Rheological, and Gel-Forming Properties.

Although dark muscle is currently the most important obstacle in marketing high-quality Indian mackerel (Rastrelliger kanagurta) surimi, reducing washing remains a challenge for long-term surimi production from this species. Herein, the impact of washing cycles (one (W1), two (W2), and three (W3) cycles) with a 1:3 mince to water ratio on the bio-physico-chemical properties, rheology, and gelling ability of mackerel surimi was evaluated. The yield, Ca2+-ATPase activity, TCA-soluble peptide, and myoglobin contents of surimi decreased as the number of washing cycles increased, while lipid removal, reactive SH content, and surface hydrophobicity of surimi increased. Surimi generated by W2 and W3 provided the same rheological patterns and Fourier-transform infrared spectroscopy (FTIR) spectra as unwashed mince, with the highest gel strength and whiteness, as well as the lowest expressible drip, thiobarbituric acid reactive substances (TBARS), and fishy odor. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) demonstrated the presence of polymerized proteins stabilized by disulfide and other interactions. Using a scanning electron microscope, several concentrated dense areas and distributed pores generated by myofibrillar proteins gel networks were found. Surimi from W2 and W3 appeared to be of similar overall quality, however W2 had a larger yield. As a result of the evaluation of bio-physico-chemical, rheological, and gel-forming capabilities, as well as product yield, W2 may be the best option for producing high-quality surimi from Indian mackerel in a sustainable manner.

Sodium Cholate-Based Active Delipidation for Rapid and Efficient Clearing and Immunostaining of Deep Biological Samples.

Recent surges of optical clearing provided anatomical maps to understand structure-function relationships at organ scale. Detergent-mediated lipid removal enhances optical clearing and allows efficient penetration of antibodies inside tissues, and sodium dodecyl sulfate (SDS) is the most common choice for this purpose. SDS, however, forms large micelles and has a low critical micelle concentration (CMC). Theoretically, detergents that form smaller micelles and higher CMC should perform better but these have remained mostly unexplored. Here, SCARF, a sodium cholate (SC)-based active delipidation method, is developed for better clearing and immunolabeling of thick tissues or whole organs. It is found that SC has superior properties to SDS as a detergent but has serious problems; precipitation and browning. These limitations are overcome by using the ion-conductive film to confine SC while enabling high conductivity. SCARF renders orders of magnitude faster tissue transparency than the SDS-based method, while excellently preserving the endogenous fluorescence, and enables much efficient penetration of a range of antibodies, thus revealing structural details of various organs including sturdy post-mortem human brain tissues at the cellular resolution. Thus, SCARF represents a robust and superior alternative to the SDS-based clearing methods and is expected to facilitate the 3D morphological mapping of various organs.

Rheological and thermal properties of oat flours and starch affected by oat lipids

Understanding how oat lipids affect the functional properties of oat flour and starch is of great importance for development of oat product. In this work, rheological and thermal properties of oat flours and starch affected by oat lipids were investigated. The peak viscosity of oat flour and starch increased as lipid content decreased. Dynamic rheological measurements showed that the storage modulus of oat flour increased, whereas that of oat starch decreased as the lipid content decreased. The gel strength of oat flour and starch increased with decreasing in lipid content. Differential scanning calorimetry results suggested that any decrease in non-starch lipid content had little influence on the properties and the formation of amylose-lipid complexes in oat flour and starch during gelatinization and retrogradation. The removal of non-starch lipids from oats increased the peak viscosity and retrogradation behavior of oat flour and starch.

Use of egg yolk to imitate meat aroma

Egg yolk contains abundant meat precursors, but its odor is quite different from meat aroma. In this study, the lipids in egg yolk were partly removed by acetone or totally removed by chloroform/methanol, and lutein was removed simultaneously by the solvents. Then, the samples were heated, and the volatiles and aroma profiles were analyzed. The results showed that chicken meat aroma and meat aroma were imitated successfully through the removal of neutral lipids and lutein (acetone-treated) and total lipids and lutein (chloroform/methanol-treated) egg yolk samples, respectively. Finally, additional lutein and tert-butylhydroquinone were employed for validating the inhibiting effects of lutein on lipid oxidation and Maillard reaction, and the results demonstrated that it was lutein rather than lipids or their degradation products that determined the flavor formation. These findings push forward the mechanisms for the formation of meat flavor and provide insights for future manufacturing of meat aroma.

Cyclodextrins increase membrane tension and are universal activators of mechanosensitive channels

The bacterial mechanosensitive channel of small conductance (MscS) has been extensively studied to understand how mechanical forces are converted into the conformational changes that underlie mechanosensitive (MS) channel gating. We showed that lipid removal by β-cyclodextrin can mimic membrane tension. Here, we show that all cyclodextrins (CDs) can activate reconstituted Escherichia coli MscS, that MscS activation by CDs depends on CD-mediated lipid removal, and that the CD amount required to gate MscS scales with the channel's sensitivity to membrane tension. Importantly, cholesterol-loaded CDs do not activate MscS. CD-mediated lipid removal ultimately causes MscS desensitization, which we show is affected by the lipid environment. While many MS channels respond to membrane forces, generalized by the "force-from-lipids" principle, their different molecular architectures suggest that they use unique ways to convert mechanical forces into conformational changes. To test whether CDs can also be used to activate other MS channels, we chose to investigate the mechanosensitive channel of large conductance (MscL) and demonstrate that CDs can also activate this structurally unrelated channel. Since CDs can open the least tension-sensitive MS channel, MscL, they should be able to open any MS channel that responds to membrane tension. Thus, CDs emerge as a universal tool for the structural and functional characterization of unrelated MS channels.

Lipid reduction to improve clarification and filterability during primary recovery of intracellular products in yeast lysates using exogenous lipase

AbstractBACKGROUNDThe yeast Pichia pastoris is a popular host organism for production of a range of biological products, several of which are intracellular. The disruption of yeast cells by homogenization also releases large quantities of lipids, which can foul the downstream membranes and chromatography matrices used for purification. This work examines lipid removal from yeast cells following homogenization by enzymatic degradation and its impact on the performance of the subsequent centrifugation and filtration.RESULTSLipase treatment of cell homogenate at 37 °C for 2 h, followed by clarification using a scaled‐down mimic of disc stack centrifugation, resulted in a 6.5‐fold improvement in solids removal when compared to untreated feed material. The lipase‐treated and untreated materials that had undergone initial centrifugation were then tested for filtration performance by passing the material through a 0.45 μm polyethylene sulfone membrane under constant flux. A 50% increase in throughput was observed in comparison to the untreated material.CONCLUSIONThese proof‐of‐concept data suggest enzymatic digestion of lipids, analogous to the widely performed DNA reduction using nucleases, could be a valuable process improvement strategy. © 2021 The Authors. Journal of Chemical Technology and Biotechnology published by John Wiley &amp; Sons Ltd on behalf of Society of Chemical Industry (SCI).

Accelerated clearing and molecular labeling of biological tissues using magnetohydrodynamic force

Techniques used to clear biological tissue for fluorescence microscopy are essential to connect anatomical principles at levels ranging from subcellular to the whole animal. Here we report a simple and straightforward approach to efficiently render opaque tissue samples transparent and show that this approach can be modified to rapidly label intact tissue samples with antibodies for large volume fluorescence microscopy. This strategy applies a magnetohydrodynamic (MHD) force to accelerate the removal of lipids from tissue samples at least as large as an intact adult mouse brain. We also show that MHD force can be used to accelerate antibody penetration into tissue samples. This strategy complements a growing array of tools that enable high-resolution 3-dimensional anatomical analyses in intact tissues using fluorescence microscopy. MHD-accelerated clearing is simple, fast, reliable, inexpensive, provides good thermal regulation, and is compatible with existing strategies for high-quality fluorescence microscopy of intact tissues.

Simultaneous Determination of Polychlorinated Biphenyl 101 (PCB101) and Its Hydroxylated, Methoxylated and Methyl Sulfonated Metabolites in Aquatic Organisms by Solid-Phase Extraction (SPE) and Gas Chromatography–Microelectron Capture Detection (GC-μECD)

Polychlorinated biphenyls (PCBs), a group of persistent organic pollutants, are ubiquitous in the environment. The concentrations of PCBs and their metabolites are crucial to understand their impact on the environment. Here, a simultaneous method is reported to determine PCB101 and its hydroxylated, methoxylated and methyl sulfonated metabolites in aquatic organisms by gas chromatography–microelectron capture detection (GC-μECD). Several operational parameters, including the extraction solvent, volume of concentrated sulfuric acid for lipid removal, elution procedure, and solid-phase extraction (SPE) eluent volume, were optimized for the analytes in the muscle tissue of carp (Carassius auratus). Under the optimum conditions, the linearity of the method was from 2.5 to 100 ng/mL with correlation coefficients (R 2) > 0.9961. The limit of detection was 2.00 μg/kg, and the limit of quantitation was equal to 5.00 μg/kg. The spiked recoveries of the targets in carp muscles were from 84.4% to 104%, and the relative standard deviation (RSD) was from 4.02% to 8.75%. The developed method was successfully applied to different aquatic samples. The precursor and metabolites were simultaneously detected in aquatic products. The metabolites of PCBs were present in marine samples collected from the East China Sea. For the first time, the methoxylated metabolite of PCB101 was identified in aquatic organisms. The results provide support for further study on the environmental properties and biological transmission of PCBs.

Method for fast lipid reconstruction and removal processing in 1 H MRSI of the brain.

To develop a new rapid spatial filtering method for lipid removal, fast lipid reconstruction and removal processing (FLIP), which selectively isolates and removes interfering lipid signals from outside the brain in a full-FOV 2D MRSI and whole-brain 3D echo planar spectroscopic imaging (EPSI). FLIP uses regularized least-squares regression based on spatial prior information from MRI to selectively remove lipid signals originating from the scalp and measure the brain metabolite signals with minimum cross contamination. FLIP is a noniterative approach, thus allowing a rapid processing speed, and uses only spatial information without any spectral priors. The performance of FLIP was compared with the Papoulis-Gerchberg algorithm (PGA), Hankel singular value decomposition (HSVD), and fast image reconstruction with L2 regularization (L2). FLIP in both 2D and 3D MRSI resulted in consistent metabolite quantification in a greater number of voxels with less concentration variation than other algorithms, demonstrating effective and robust lipid-removal performance. The percentage of voxels that met quality criteria with FLIP, PGA, HSVD, and L2 processing were 90%, 57%, 29%, and 42% in 2D MRSI, and 80%, 75%, 76%, and 74% in 3D EPSI, respectively. The quantification results of full-FOV MRSI using FLIP were comparable to those of volume-localized MRSI, while allowing significantly increased spatial coverage. FLIP performed the fastest in 2D MRSI. FLIP is a new lipid-removal algorithm that promises fast and effective lipid removal with improved volume coverage in MRSI.

Lipid bilayer degradation induced by SARS-CoV-2 spike protein as revealed by neutron reflectometry

SARS-CoV-2 spike proteins are responsible for the membrane fusion event, which allows the virus to enter the host cell and cause infection. This process starts with the binding of the spike extramembrane domain to the angiotensin-converting enzyme 2 (ACE2), a membrane receptor highly abundant in the lungs. In this study, the extramembrane domain of SARS-CoV-2 Spike (sSpike) was injected on model membranes formed by supported lipid bilayers in presence and absence of the soluble part of receptor ACE2 (sACE2), and the structural features were studied at sub-nanometer level by neutron reflection. In all cases the presence of the protein produced a remarkable degradation of the lipid bilayer. Indeed, both for membranes from synthetic and natural lipids, a significant reduction of the surface coverage was observed. Quartz crystal microbalance measurements showed that lipid extraction starts immediately after sSpike protein injection. All measurements indicate that the presence of proteins induces the removal of membrane lipids, both in the presence and in the absence of ACE2, suggesting that sSpike molecules strongly associate with lipids, and strip them away from the bilayer, via a non-specific interaction. A cooperative effect of sACE2 and sSpike on lipid extraction was also observed.

Determination of 6 biogenic amines in food using high-performance liquid chromatography-tandem mass spectrometry without derivatization

A rapid and simple method for the determination of 6 biogenic amines (BAs) in food was established on HPLC-MS /MS without derivatization. Samples were extracted with 5% perchloric acid and cleaned with n-hexane for lipid removal. The analytes were separated on Waters XBridge® HILIC (150 mm × 2.1 mm, 3.5 µm) and analyzed with multiple-reaction monitoring (MRM) mode after positive electrospray ionization on HPLC-MS/MS. Good linearity with high correlation coefficient was obtained between 10-1000 µg/L for cadaverine (CAD), putrescine (PUT), tyramine (TYR) and 2-phenylethylamine (2-PHE) and between 1-100 µg/L for histamine (HIS) and tryptamine (TRY), with the detection limits of the method ranging from 0.1 mg/kg for HIS and TRY, and 1.0 mg/kg for CAD, PUT, TYR and 2-PHE, which are under the residue limit of Chinese regulation. Spiking experiments demonstrated good recoveries between 70.2-114.6%, with relative standard deviations (RSDs) between 0.44-13.01%. This method was validated for BAs determination in liquor, fermented meat products, vegetable products, soybean products, dairy products, seafood and its derived products. These results promise high feasibility for BAs monitoring in various food with easy-to-operate and fast sample preparation process, stable analysis on HPLC-MS/MS without derivatization.

Measuring impacts of microplastic treatments via image recognition on immobilised particles below 100\u2009\u03bcm

The treatment of samples for microplastic (MP) analysis requires purification steps that sufficiently reduce the non-MP content while preserving the targeted particles integrity. Besides their macromolecular structure this also encompasses their in situ numbers and sizes. However, any step of sample manipulation will come at a cost: particle loss, fragmentation, coagulation or degradation may lead to distorted results, predominantly in the smaller fraction of the MP size range. Therefore, the evaluation of MP resistivity against applied methods such as chemical digestions is a vital criterion for obtaining meaningful results on MP content of a sample. We developed a framework to test the applicability of MP purification methods and apply it to four protocols commonly used to prepare environmental samples for MP particle identification. The approach was designed for MP particles being too small to be handled manually (i.e. 10–70 μm). The evaluation consists of a two-tiered assay: a simple particle suspension approach is used to confirm a post-treatment qualitative recognisability of the target polymers by the analysis method of choice (here Raman and FTIR). In a following quantitative part, immobilised particles are used to evaluate the preservation of particle numbers and areas after the treatment on an individual particle level. A Python image analysis package was written that identifies, matches and measures particles on pairs of pre- and post-treatment images, and is available as open source software. Our results show that the chemical digestions using hydrogen peroxide, cooled Fenton’s and a combined alkaline / oxidative treatment using potassium hydroxide and sodium hypochlorite are suitable methods for preparing MP samples for a microspectroscopic analyses. Also acidic sodium polytungstate solution used for MP density separations and a pentane based protocol for lipid removal were found applicable for small sized MP. Certain degradative effects were found when acrylonitrile butadiene styrene is exposed to acidic treatments, as well as for MP from acrylate and epoxy based paint resins in strong oxidative regimes. Several paint resins tested here were spectroscopically not identifiable by polymer attributed bands even before treatment, indicating that these materials might slip through analyses of environmental samples and consequently being underreported. We conclude that evaluating chemical treatment procedures on MP < 100 μm is feasible, despite limitations of the current methodology which we discuss. Our results provide more certainty on the tested methods for MP studies specifically targeting small sizes and should be extended for more protocols used in MP laboratory practises.

Evaluation of real-time qPCR-based methods to detect the DNA of the three protozoan parasites Cryptosporidium parvum, Giardia duodenalis and Toxoplasma gondii in the tissue and hemolymph of blue mussels (M. edulis)

The protozoan parasites Cryptosporidium spp., Giardia duodenalis and Toxoplasma gondii can be transmitted to humans through shellfish consumption. No standardized methods are available for their detection in these foods, and the performance of the applied methods are rarely described in occurrence studies. Through spiking experiments, we characterized different performance criteria (e.g. sensitivity, estimated limit of detection (eLD95METH), parasite DNA recovery rates (DNA-RR)) of real-time qPCR based-methods for the detection of the three protozoa in mussel's tissues and hemolymph. Digestion of mussels tissues by trypsin instead of pepsin and the use of large buffer volumes was the most efficient for processing 50g-sample. Trypsin digestion followed by lipids removal and DNA extraction by thermal shocks and a BOOM-based technique performed poorly (e.g. eLD95METH from 30 to >3000 parasites/g). But trypsin digestion and direct DNA extraction by bead-beating and FastPrep homogenizer achieved higher performance (e.g. eLD95METH: 4–400 parasites/g, DNA-RR: 19–80%). Direct DNA recovery from concentrated hemolymph, by thermal shocks and cell lysis products removal was not efficient to sensitively detect the protozoa (e.g. eLD95METH: 10–1000 parasites/ml, DNA-RR ≤ 24%). The bead-beating DNA extraction based method is a rapid and simple approach to sensitively detect the three protozoa in mussels using tissues, that can be standardized to different food matrices. However, quantification in mussels remains an issue.

Abstract 2751: Secreted fatty acids from head and neck cancer cell lines mediate M2-like macrophage polarization

Abstract Head and neck cancers (HNC) can persist despite infiltration of immune cells into the tumor microenvironment. One mechanism that may contribute to failed immune clearance of tumors stems from the conditioning of tumor infiltrating macrophages into a cell type that supports tumor survival rather than a cell with pro-inflammatory characteristics. To understand mechanisms that lead to conditioning of macrophages by tumors, we assessed the effects of HNC cell lines on macrophage maturation. Macrophages were matured by incubating purified human monocytes for 3-4 days in medium alone or in medium supplemented with supernatants from HNC cell lines (FADU and SCC9) or a human leukemia monocytic cell line (THP-1). Macrophages were recovered and examined by flow cytometry for markers of maturation (CD14, CD68), activation (HLA-DR, CD86, and IL-15R), scavenger receptor (CD36), toll-like receptor (TLR4), M2 marker (CD206), immune checkpoint (PD-L1) and intracellular chemokine expression (IP-10). Relative to unconditioned macrophages or cells exposed to THP-1 supernatants, cells incubated with FADU or SCC9 supernatants displayed enhanced survival, downregulation of cell surface HLA-DR, CD86, IL-15R, CD36 and intracellular IP-10 expression. In contrast, the expression of PD-L1, CD14, and CD206 were increased by HNC cell line supernatants. To assess function, matured macrophages were stimulated overnight with the TLR4 agonist, LPS. Induction of macrophage activation was measured by increased expression of HLA-DR and IL-15R. Despite sustained the expression of TLR4 and CD14, macrophages matured in HNC supernatants failed to upregulate HLA-DR and IL-15R expression when stimulated with the canonical TLR4 agonist, LPS. These phenotypic and functional changes were accompanied by a decrease in intracellular phospho-p38 expression and a robust induction of WIP-1 phosphatase. Next, we considered the hypothesis that fatty acids released from tumors might contribute to these phenotypes. To test this, we added Etomoxir, an inhibitor of fatty acid oxidation, into cell cultures during exposure to tumor supernatants. The addition of Etomoxir reversed a number of these phenotypic changes induced by tumor supernatants with the exception of PD-L1 induction. Moreover, depletion of fatty acids from tumor supernatants with lipid removal agent, mitigated the effects of supernatants on macrophage maturation. Additionally, we found that macrophages incubated with either palmitic acid or oleic acid for 3-4 days developed similar phenotypes as cells incubated in tumor supernatants. Together, our data suggest that fatty acids are both necessary in tumor supernatants and sufficient on their own to mediate maturation of macrophages into a cell type with limited pro-inflammatory characteristics (M2-like). Approaches that modify the expression or effects of fatty acids in tumor microenvironment may be useful in HNC. Citation Format: Marwah M. Albakri, Stanley C. Huang, Hammad Tashkandi, Scott F. Sieg. Secreted fatty acids from head and neck cancer cell lines mediate M2-like macrophage polarization [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 2751.

Effect of protein denaturation and lipid removal on rice physicochemical properties

The physicochemical properties of rice are influenced by their chemical components and their interactions. It has been demonstrated that the interactions among rice chemical components are enhanced by protein denaturation (PD) via heat treatment and by lipid removal (LR) via solvent extraction. The objective of this study was to investigate the impacts of PD, LR, and their combined treatments on the gelatinization and pasting properties, swelling power, and water solubility of four brown rice flours. Rice protein was denatured under a vacuum at 100 °C, and rice lipid was removed via hexane for varying times. The combined treatments were done in two ways, PD followed by LR (PD-LR), and LR followed by PD (LR-PD). The results showed that PD increased gelatinization temperatures, while LR decreased gelatinization temperatures. Both PD and LR reduced pasting and swelling properties; however, PD resulted in a greater decrease than LR. Polar lipids are proposed to serve as bridges to link denatured proteins and starch granules in the combined treatments, resulting in greater decreases in the pasting and swelling properties than the individual treatments. The results obtained in this study demonstrate the importance of starch-lipid-protein interactions on the physicochemical properties of brown rice flour.

A simple extraction method with no lipid removal for the determination of aflatoxins in almonds by liquid chromatography tandem-mass spectrometry (LC-MS/MS)

ABSTRACT The present study describes a simple and rapid method for the determination of aflatoxins in almonds using liquid chromatography-tandem mass spectrometry (LC-MS/MS). Aflatoxins were extracted using a modified QuEChERS method with little sample preparation, excluding the use of laborious purification procedures. Extracts were frozen overnight to separate the majority of lipids. The method was successfully validated for almonds. Linearity was demonstrated in the range 0.125–20 µg/kg. Limits of quantification (LOQ) ranged from 0.34 to 0.5 μg/kg. Matrix effect was not significant for the aflatoxins. Satisfactory recoveries were obtained at spike levels below 1 μg/kg and between 1 and 10 μg/kg. Relative standard deviations (RSDs) of repeatability and reproducibility were below 15%. The method was successfully tested with two proficiency tests in almond powder and peanut paste, with acceptable z-scores (−2 ≤ z ≤ 2). Only one of 11 local almond samples contained detectable aflatoxins, at concentrations below the maximum permitted level.