Membrane surface properties of lymphocytes of normal (DBA/2) and autoimmune (NZB/NZW)F1 mice: effects of L-canavanine and a proposed mechanism for diet-induced autoimmune disease

1986 ◽  
Vol 64 (9) ◽  
pp. 1189-1196 ◽  
Author(s):  
Pamela E. Prete
Keyword(s):  
New Zealand ◽  
B Cells ◽  
Membrane Surface ◽  
Surface Membrane ◽  
Countercurrent Distribution ◽  
Membrane Properties ◽  
Phase System ◽  
Two Phase ◽  
The Right

Partitioning cells in a dextran polyethylene glycol aqueous two-phase system (countercurrent distribution, CCD) is a sensitive method for learning about cell surface membrane properties and for subfractionating cell populations. In this study, we subjected lymphocytes from normal DBA/2 mice and autoimmune F1 New Zealand black/New Zealand white ((NZB/NZW)F1) mice to countercurrent distribution and found that T cells partition to the right and B cells partition to the left of the CCD curve. We found no difference between the CCD patterns of normal and autoimmune mice. When the murine lymphocytes were exposed to a cationic dietary amino acid (L-canavanine) in vitro, L-canavanine selectively affected the CCD pattern of autoimmune B cells, reflecting an alteration in surface membrane properties. We separated these lymphocytes with altered surface membrane properties by CCD. Impaired B-cell immune responses associated with L-canavanine were isolated to this lymphocyte fraction. This study provides the first evidence that alterations in the charged surface membrane properties are associated with abnormal (auto) immune response.

Ultrasonic-Assisted Aqueous Two-Phase Extraction Combined with Macroporous Resin Enrichment of Lignans from Flaxseed Meal and Their Antioxidant Activities

2021 ◽  
Author(s):  
Zhizhou Zhang ◽  
Yongchao Zhang ◽  
Yichao Wu ◽  
Yongxiang Xu ◽  
Yuanyuan Jiang ◽  
...  
Keyword(s):  
Antioxidant Activities ◽  
Phase System ◽  
Extraction Temperature ◽  
Macroporous Resin ◽  
Two Phase ◽  
Solid Ratio ◽  
Flaxseed Meal ◽  
Extraction And Purification ◽  
Ultrasonic Assisted

Abstract Background Secoisolariciresinol di glucoside (SDG) is a natural antioxidant generally extracted from flaxseed, which is one of the most important oil crops in China, the by-product of the flaxseed oil, i.e., flaxseed meal, still contains a lot of lignans. However, flaxseed meal is generally treated as waste, resulting in a huge waste of resources. Objective To establish an efficient and convenient method for extraction and purification of lignans from flaxseed meal. Methods First, we used response surface methodology (RSM) to optimize the extraction conditions of the ultrasonic-assisted aqueous two-phase system (UAATPS), and we obtained the purified extracts by macroporous resin purification (MRP). Second, the antioxidant ability of the extracts was studied in vitro. Results The best extraction conditions obtained were as follows: 9.0 wt% sodium hydroxide, 30.0 wt% isopropanol, extraction time 39 min, liquid-to-solid ratio of 52.0 mL/g, ultrasonic wave 560 W, and extraction temperature 40 °C. Under the optimal conditions, the purity of crude extracts (SDG-APTS-C) reached 21.5%. The desorption conditions of MRP were as follows: eluting 3 BV with ultrapure water, and then eluting with 25% ethanol at 2 BV/h to collect eluents. The purified extracts (SDG-ATPS-P) had a purity quotient of 73.9%, 52.4% higher than that of SDG-ATPS-C. Additionally, experiments conducted in this paper revealed that SDG-ATPS-C and SDG-ATPS-P could effectively remove DPPH, ABTS, and hydroxyl free radicals in vitro. Conclusions The method was validated for extracting SDG from flaxseed meal, thus achieving the reuse of flaxseed meal. Highlights This research provides some references for the application of UAATPS combined with MRP in natural products.

A Device for Countercurrent Distribution of Particles by an Aqueous Polymer Two-Phase System

1978 ◽  
Vol 13 (9) ◽  
pp. 745-752 ◽  
Author(s):  
Hiroyuki Nakazawa ◽  
Takenori Tanimura ◽  
Zenzo Tamura
Keyword(s):  
Countercurrent Distribution ◽  
Phase System ◽  
Two Phase ◽  
Aqueous Polymer

scholarly journals The enterocyte microvillus is a vesicle-generating organelle

2009 ◽  
Vol 185 (7) ◽  
pp. 1285-1298 ◽  
Author(s):  
Russell E. McConnell ◽  
James N. Higginbotham ◽  
David A. Shifrin ◽  
David L. Tabb ◽  
Robert J. Coffey ◽  
...  
Keyword(s):  
Brush Border ◽  
Membrane Surface ◽  
Intestinal Lumen ◽  
Intestinal Alkaline Phosphatase ◽  
Brush Border Enzymes ◽  
Membrane Surface Area ◽  
Catalytically Active ◽  
The Right

For decades, enterocyte brush border microvilli have been viewed as passive cytoskeletal scaffolds that serve to increase apical membrane surface area. However, recent studies revealed that in the in vitro context of isolated brush borders, myosin-1a (myo1a) powers the sliding of microvillar membrane along core actin bundles. This activity also leads to the shedding of small vesicles from microvillar tips, suggesting that microvilli may function as vesicle-generating organelles in vivo. In this study, we present data in support of this hypothesis, showing that enterocyte microvilli release unilamellar vesicles into the intestinal lumen; these vesicles retain the right side out orientation of microvillar membrane, contain catalytically active brush border enzymes, and are specifically enriched in intestinal alkaline phosphatase. Moreover, myo1a knockout mice demonstrate striking perturbations in vesicle production, clearly implicating this motor in the in vivo regulation of this novel activity. In combination, these data show that microvilli function as vesicle-generating organelles, which enable enterocytes to deploy catalytic activities into the intestinal lumen.

scholarly journals Preparation, Characterization, and Optimization of an In Vitro C30 Carotenoid Pathway

2005 ◽  
Vol 71 (11) ◽  
pp. 6578-6583 ◽  
Author(s):  
Bosung Ku ◽  
Jae-Cheol Jeong ◽  
Benjamin N. Mijts ◽  
Claudia Schmidt-Dannert ◽  
Jonathan S. Dordick
Keyword(s):  
Phase System ◽  
Reaction Conditions ◽  
Two Phase ◽  
Gene Encoding ◽  
In Situ Extraction ◽  
Steady State Kinetics ◽  
Wide Range ◽  
Carotenoid Synthesis

ABSTRACT The ispA gene encoding farnesyl pyrophosphate (FPP) synthase from Escherichia coli and the crtM gene encoding 4,4′-diapophytoene (DAP) synthase from Staphylococcus aureus were overexpressed and purified for use in vitro. Steady-state kinetics for FPP synthase and DAP synthase, individually and in sequence, were determined under optimized reaction conditions. For the two-step reaction, the DAP product was unstable in aqueous buffer; however, in situ extraction using an aqueous-organic two-phase system resulted in a 100% conversion of isopentenyl pyrophosphate and dimethylallyl pyrophosphate into DAP. This aqueous-organic two-phase system is the first demonstration of an in vitro carotenoid synthesis pathway performed with in situ extraction, which enables quantitative conversions. This approach, if extended to a wide range of isoprenoid-based pathways, could lead to the synthesis of novel carotenoids and their derivatives.

scholarly journals Silver Nanoparticles and Polyphenol Inclusion Compounds Composites for Phytophthora cinnamomi Mycelial Growth Inhibition

Antibiotics ◽  
2018 ◽  
Vol 7 (3) ◽  
pp. 76 ◽  
Author(s):  
Petruta Matei ◽  
Jesús Martín-Gil ◽  
Beatrice Michaela Iacomi ◽  
Eduardo Pérez-Lebeña ◽  
María Barrio-Arredondo ◽  
...  
Keyword(s):  
Silver Nanoparticles ◽  
Growth Inhibition ◽  
Inclusion Compounds ◽  
Mycelial Growth ◽  
Water Solubility ◽  
Phytophthora Cinnamomi ◽  
Deep Eutectic Solvent ◽  
Phase System ◽  
Two Phase

Phytophthora cinnamomi, responsible for “root rot” or “dieback” plant disease, causes a significant amount of economic and environmental impact. In this work, the fungicide action of nanocomposites based on silver nanoparticles and polyphenol inclusion compounds, which feature enhanced bioavailability and water solubility, was assayed for the control of this soil-borne water mold. Inclusion compounds were prepared by an aqueous two-phase system separation method through extraction, either in an hydroalcoholic solution with chitosan oligomers (COS) or in a choline chloride:urea:glycerol deep eutectic solvent (DES). The new inclusion compounds were synthesized from stevioside and various polyphenols (gallic acid, silymarin, ferulic acid and curcumin), in a [6:1] ratio in the COS medium and in a [3:1] ratio in the DES medium, respectively. Their in vitro response against Phytophthora cinnamomi isolate MYC43 (at concentrations of 125, 250 and 500 µg·mL−1) was tested, which found a significant mycelial growth inhibition, particularly high for the composites prepared using DES. Therefore, these nanocomposites hold promise as an alternative to fosetyl-Al and metalaxyl conventional systemic fungicides.

Surface changes of ram spermatozoa by adsorption of homologous and heterologous seminal plasma proteins revealed by partition in an aqueous two-phase system

1997 ◽  
Vol 9 (4) ◽  
pp. 381 ◽  
Author(s):  
M. Ollero ◽  
N. García-López ◽  
R. Pérez-Pé ◽  
J. A. Cebrián-Pérez ◽  
T. Muiño-Blanco
Keyword(s):  
Cell Viability ◽  
Seminal Plasma ◽  
Plasma Proteins ◽  
Surface Proteins ◽  
Live Cells ◽  
Tween 20 ◽  
Phase System ◽  
Two Phase ◽  
Seminal Plasma Proteins ◽  
The Right

Ram spermatozoa freed from seminal plasma by a dextran ‘swim-up’ procedure were incubated with Tween 20 and fractionated into motile (PEG-rich) and stationary (dextran-rich) fractions by centrifugal countercurrent distribution (CCCD) in an aqueous dextran–Ficoll– polyethylene glycol (PEG) two-phase system. Increasing concentrations of Tween 20 resulted in greater amounts of extracted protein and lower cell viability. Addition of bull seminal plasma increased the proportion of live cells, whereas ram seminal plasma increased the proportion of stationary cells. Proteins isolated from each type of seminal plasma restored the CCCD profile of treated spermatozoa to the right, this effect being reduced when proteins were thermally denatured. Bovine serum albumin induced a slight displacement to the left. No restoration of profile was achieved when ram spermatozoa were exposed to proteins from bull seminal plasma in the presence of protein-free ram seminal plasma. Adsorption of seminal plasma proteins by spermatozoa previously stripped of surface proteins by exposure to detergent reversed the detergent effect on motility. The findings are consistent with the concept that ram seminal plasma contains a factor that interferes with protein adsorption on the cell surface and prevents the protective effect of seminal plasma proteins on maintenance of cell viability

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