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1.
Membranes (Basel) ; 14(6)2024 Jun 03.
Article in English | MEDLINE | ID: mdl-38921495

ABSTRACT

This study investigated the use of chicken egg white (CEW) waste immobilized on weak acidic nanofiber membranes for removing the anionic acid orange 7 (AO7) dye in batch and continuous flow modes. Different experiments were conducted to evaluate the effectiveness of CEW-modified nanofiber membranes for AO7 removal, focusing on CEW immobilization conditions, adsorption kinetics, and thermodynamics. The CEW-modified nanofiber membrane (namely NM-COOH-CEW) exhibited a maximum AO7 adsorption capacity of 589.11 mg/g within approximately 30 min. The Freundlich isotherm model best represented the equilibrium adsorption data, while the adsorption kinetics followed a pseudo-second-order rate model. Breakthrough curve analysis using the Thomas model and the bed depth service time (BDST) model showed that the BDST model accurately described the curve, with an error percentage under 5%. To investigate AO7 elution efficiency, different concentrations of organic solvents or salts were tested as eluents. The NM-COOH-CEW nanofiber membrane exhibited promising performance as an effective adsorbent for removing AO7 dye from contaminated water.

2.
Updates Surg ; 2024 Jun 05.
Article in English | MEDLINE | ID: mdl-38839724

ABSTRACT

The current study aimed to investigate whether previous abdominal surgery (PAS) could affect the outcomes of colorectal cancer (CRC) surgery. We conducted the search strategy in three databases (PubMed, Embase, and the Cochrane Library) from inception to May 26, 2022. The short-term and long-term outcomes were compared between the PAS group and the non-PAS group. Odds ratios (ORs) and 95% confidence intervals (CIs) were pooled up. Stata (V.16.0) software was used for data analysis. We included 34,827 patients from 14 studies in the current study. After pooling up all the data, we found that there were higher proportions of overall complications (OR = 1.12, I2 = 4.65%, 95% CI 1.03 to 1.23, P = 0.01), ileus (OR = 1.96, I2 = 59.74%, 95% CI 1.12 to 3.44, P = 0.02) and mortality (OR = 1.26, I2 = 0.00%, 95% CI 1.11 to 1.42, P = 0.00) in the PAS group than the non-PAS group. Patients with a history of PAS had higher risks of overall complications and death following CRC surgery. However, it did not appear to significantly affect the short-term outcomes apart from ileus. Surgeons should raise awareness of patients with a history of PAS, and take steps to reduce postoperative complications and mortality.

3.
Nucleic Acids Res ; 52(12): 6811-6829, 2024 Jul 08.
Article in English | MEDLINE | ID: mdl-38676947

ABSTRACT

Protein arginine methyltransferase CARM1 has been shown to methylate a large number of non-histone proteins, and play important roles in gene transcriptional activation, cell cycle progress, and tumorigenesis. However, the critical substrates through which CARM1 exerts its functions remain to be fully characterized. Here, we reported that CARM1 directly interacts with the GATAD2A/2B subunit in the nucleosome remodeling and deacetylase (NuRD) complex, expanding the activities of NuRD to include protein arginine methylation. CARM1 and NuRD bind and activate a large cohort of genes with implications in cell cycle control to facilitate the G1 to S phase transition. This gene activation process requires CARM1 to hypermethylate GATAD2A/2B at a cluster of arginines, which is critical for the recruitment of the NuRD complex. The clinical significance of this gene activation mechanism is underscored by the high expression of CARM1 and NuRD in breast cancers, and the fact that knockdown CARM1 and NuRD inhibits cancer cell growth in vitro and tumorigenesis in vivo. Targeting CARM1-mediated GATAD2A/2B methylation with CARM1 specific inhibitors potently inhibit breast cancer cell growth in vitro and tumorigenesis in vivo. These findings reveal a gene activation program that requires arginine methylation established by CARM1 on a key chromatin remodeler, and targeting such methylation might represent a promising therapeutic avenue in the clinic.


Subject(s)
Breast Neoplasms , Chromatin Assembly and Disassembly , Gene Expression Regulation, Neoplastic , Mi-2 Nucleosome Remodeling and Deacetylase Complex , Protein-Arginine N-Methyltransferases , Mi-2 Nucleosome Remodeling and Deacetylase Complex/metabolism , Mi-2 Nucleosome Remodeling and Deacetylase Complex/genetics , Protein-Arginine N-Methyltransferases/genetics , Protein-Arginine N-Methyltransferases/metabolism , Breast Neoplasms/genetics , Breast Neoplasms/pathology , Breast Neoplasms/metabolism , Humans , Female , Animals , Cell Line, Tumor , Cell Cycle/genetics , Mice , Methylation , Arginine/metabolism , Carcinogenesis/genetics , Transcriptional Activation
4.
Cell Rep ; 42(11): 113385, 2023 11 28.
Article in English | MEDLINE | ID: mdl-37938975

ABSTRACT

PRMT1 plays a vital role in breast tumorigenesis; however, the underlying molecular mechanisms remain incompletely understood. Herein, we show that PRMT1 plays a critical role in RNA alternative splicing, with a preference for exon inclusion. PRMT1 methylome profiling identifies that PRMT1 methylates the splicing factor SRSF1, which is critical for SRSF1 phosphorylation, SRSF1 binding with RNA, and exon inclusion. In breast tumors, PRMT1 overexpression is associated with increased SRSF1 arginine methylation and aberrant exon inclusion, which are critical for breast cancer cell growth. In addition, we identify a selective PRMT1 inhibitor, iPRMT1, which potently inhibits PRMT1-mediated SRSF1 methylation, exon inclusion, and breast cancer cell growth. Combination treatment with iPRMT1 and inhibitors targeting SRSF1 phosphorylation exhibits an additive effect of suppressing breast cancer cell growth. In conclusion, our study dissects a mechanism underlying PRMT1-mediated RNA alternative splicing. Thus, PRMT1 has great potential as a therapeutic target in breast cancer treatment.


Subject(s)
Alternative Splicing , Breast Neoplasms , Humans , Female , Methylation , Alternative Splicing/genetics , Cell Transformation, Neoplastic/genetics , RNA/metabolism , Breast Neoplasms/genetics , Exons/genetics , Serine-Arginine Splicing Factors/genetics , Serine-Arginine Splicing Factors/metabolism , Protein-Arginine N-Methyltransferases/genetics , Protein-Arginine N-Methyltransferases/metabolism , Repressor Proteins/genetics , Repressor Proteins/metabolism
5.
Sci Total Environ ; 822: 153304, 2022 May 20.
Article in English | MEDLINE | ID: mdl-35090923

ABSTRACT

Basalt-derived soils are widespread worldwide. Such soils contain high levels of heavy metals like chromium (Cr), which is a serious environmental concern. However, little is known regarding the enrichment and speciation of Cr during the basalt weathering process. Therefore, two basalt-derived soil profiles (Nitisol and Ferralsol) in the Leizhou Peninsula, south tropical China, were investigated to explore the redistribution and transformation of Cr during basalt weathering. All profiles could be divided into three layers: rocks, saprolites, and soils. The Nitisol and Ferralsol profiles exhibited strong (kaolinization) and extreme (laterization) degrees of weathering, respectively. Results showed that Cr concentrations in the saprolites (234 to 315 mg·kg-1) were higher than those in basalt rocks (139 to 159 mg·kg-1), indicating that Cr was enriched with the continuous loss of Si and other mobile macro-elements. While high levels of Cr were also enriched in the soils (178 to 430 mg·kg-1) accompanied with Fe. However, in the upper soils of the Ferralsol profile, the acidity and organic matter could promote the leaching of Cr. Geochemical fractions and EPMA mapping showed that chromite and olivine were the main Cr-bearing minerals in basalt, but Fe-oxides (e.g., goethite and hematite) contained the highest portion of Cr in weathered saprolites and soils. The availability of Cr in the soil was extremely low due to the high stability of Cr bound to Fe-oxides. However, the decreasing contents of Cr bound to Fe-oxides in the upper soils of the Ferralsol profile indicated that Cr could also be released during Fe leaching. In conclusion, the weathering of basalt can lead to the enrichment of Cr in Fe-(hydro)oxides, which are the main controlling minerals for Cr mobility in basalt-derived soils. Further research is needed to evaluate the effect of Fe-(hydro)oxide formation and dissolution on the release of soil Cr.


Subject(s)
Chromium , Soil Pollutants , China , Chromium/analysis , Environmental Monitoring , Silicates , Soil/chemistry , Soil Pollutants/analysis
6.
Int J Biol Macromol ; 185: 761-772, 2021 Aug 31.
Article in English | MEDLINE | ID: mdl-34216668

ABSTRACT

Cylinder-shaped NaY zeolite was used as an adsorbent for eradicating both heavy metal ions (Cu2+, Zn2+, Ni2+, and Co2+) and proteins from the waste streams. As a pseudo-metal ion affinity adsorbent, NaY zeolite was used in the capture of heavy metal ions in the first stage. The amount (molar basis) of metal ions adsorbed onto NaY zeolite decreased in the order of Cu2+ > Zn2+ > Co2+ > Ni2+. Bovine serum albumin (BSA) was utilized as a model of proteins used in the waste adsorption process by NaY zeolite. The adsorption capacities of NaY zeolite and Cu/NaY zeolite for BSA were 14.90 mg BSA/g zeolite and 84.61 mg BSA/g zeolite, respectively. Moreover, Cu/NaY zeolite was highly stable in the solutions made of 2 M NaCl, 500 mM imidazole or 125 mM EDTA solutions. These conditions indicated that the minimal probability of secondary contamination caused by metal ions and soluble proteins in the waste stream. This study demonstrates the potential of Cu/NaY zeolite complex as an efficient pseudo-metal chelate adsorbent that could remove metal ions and water-soluble proteins from wastewater concurrently.


Subject(s)
Metals, Heavy/analysis , Serum Albumin, Bovine/analysis , Water Pollutants, Chemical/analysis , Zeolites/chemistry , Adsorption , Chelating Agents , Hydrogen-Ion Concentration , Wastewater/chemistry
7.
Food Chem ; 358: 129914, 2021 Oct 01.
Article in English | MEDLINE | ID: mdl-34000689

ABSTRACT

A high-performance polyacid ion exchange (IEX) nanofiber membrane was used in membrane chromatography for the recovery of lysozyme from chicken egg white (CEW). The polyacid IEX nanofiber membrane (P-BrA) was prepared by the functionalization of polyacrylonitrile (PAN) nanofiber membrane with ethylene diamine (EDA) and bromoacetic acid (BrA). The adsorption performance of P-BrA was evaluated under various operating conditions using Pall filter holder. The results showed that optimal conditions of IEX membrane chromatography for lysozyme adsorption were 10% (w/v) of CEW, pH 9 and 0.1 mL/min. The purification factor and yield of lysozyme were 402 and 91%, respectively. The adsorption process was further scaled up to a larger loading volume, and the purification performance was found to be consistent. Furthermore, the regeneration of IEX nanofiber membrane was achieved under mild conditions. The adsorption process was repeated for five times and the adsorption capacity of adsorber was found to be unaffected.


Subject(s)
Chromatography, Ion Exchange/instrumentation , Chromatography, Ion Exchange/methods , Egg White/chemistry , Membranes, Artificial , Muramidase/isolation & purification , Acetates/chemistry , Acrylic Resins/chemistry , Adsorption , Animals , Chickens , Ethylenediamines/chemistry , Hydrogen-Ion Concentration , Muramidase/chemistry , Nanofibers/chemistry
8.
Carbohydr Polym ; 262: 117910, 2021 Jun 15.
Article in English | MEDLINE | ID: mdl-33838797

ABSTRACT

N-[(2-hydroxyl-3-trimethylammonium) propyl] chitosan chloride (HTCC), which is a type of chitosan derivative with quaternary ammonium groups, possesses a higher antibacterial activity as compared to the pristine chitosan. The nanofiber membranes made of HTCC are attractive for applications demanding for antibacterial function. However, the hydrophilic nature of HTCC makes it unsuitable for electrospinning of nanofibers. Hence, biodegradable polyvinyl alcohol (PVA) was proposed as an additive to improve the electrospinnability of HTCC. In this work, PVA/HTCC nanofiber membrane was crosslinked with the blocked diisocyanate (BI) to enhance the stability of nanofiber membrane in water. Microbiological assessments showed that the PVA/HTCC/BI nanofiber membranes possessed a good antibacterial efficacy (∼100 %) against E. coli. Moreover, the biocompatibility of PVA/HTCC/BI nanofiber membrane was proven by the cytotoxicity test on mouse fibroblasts. These promising results indicated that the PVA/HTCC/BI nanofiber membrane can be a promising material for food packaging and as a potential wound dressing for skin regeneration.


Subject(s)
Anti-Bacterial Agents/pharmacology , Chitosan/chemistry , Isocyanates/chemistry , Nanofibers/chemistry , Polyvinyl Alcohol/chemistry , Animals , Anti-Bacterial Agents/chemistry , Bandages , Cell Line , Chitosan/analogs & derivatives , Cross-Linking Reagents/chemistry , Escherichia coli/drug effects , Food Packaging/methods , Hydrophobic and Hydrophilic Interactions , Mice , Quaternary Ammonium Compounds/chemistry
9.
Nat Commun ; 12(1): 1946, 2021 03 29.
Article in English | MEDLINE | ID: mdl-33782401

ABSTRACT

Numerous substrates have been identified for Type I and II arginine methyltransferases (PRMTs). However, the full substrate spectrum of the only type III PRMT, PRMT7, and its connection to type I and II PRMT substrates remains unknown. Here, we use mass spectrometry to reveal features of PRMT7-regulated methylation. We find that PRMT7 predominantly methylates a glycine and arginine motif; multiple PRMT7-regulated arginine methylation sites are close to phosphorylations sites; methylation sites and proximal sequences are vulnerable to cancer mutations; and methylation is enriched in proteins associated with spliceosome and RNA-related pathways. We show that PRMT4/5/7-mediated arginine methylation regulates hnRNPA1 binding to RNA and several alternative splicing events. In breast, colorectal and prostate cancer cells, PRMT4/5/7 are upregulated and associated with high levels of hnRNPA1 arginine methylation and aberrant alternative splicing. Pharmacological inhibition of PRMT4/5/7 suppresses cancer cell growth and their co-inhibition shows synergistic effects, suggesting them as targets for cancer therapy.


Subject(s)
Breast Neoplasms/genetics , Colorectal Neoplasms/genetics , Heterogeneous Nuclear Ribonucleoprotein A1/genetics , Prostatic Neoplasms/genetics , Protein-Arginine N-Methyltransferases/genetics , Alternative Splicing , Amino Acid Sequence , Arginine/metabolism , Breast Neoplasms/metabolism , Breast Neoplasms/pathology , Cell Cycle/drug effects , Cell Cycle/genetics , Cell Line, Tumor , Colorectal Neoplasms/metabolism , Colorectal Neoplasms/pathology , Enzyme Inhibitors/pharmacology , Female , Gene Expression Profiling , Gene Expression Regulation, Neoplastic , HEK293 Cells , Heterogeneous Nuclear Ribonucleoprotein A1/antagonists & inhibitors , Heterogeneous Nuclear Ribonucleoprotein A1/metabolism , Humans , Male , Methylation/drug effects , Prostatic Neoplasms/metabolism , Prostatic Neoplasms/pathology , Protein Binding , Protein Processing, Post-Translational , Protein-Arginine N-Methyltransferases/antagonists & inhibitors , Protein-Arginine N-Methyltransferases/metabolism , RNA, Small Interfering/genetics , RNA, Small Interfering/metabolism , Spliceosomes/drug effects , Spliceosomes/genetics , Spliceosomes/metabolism , Substrate Specificity
10.
Int J Biol Macromol ; 181: 508-520, 2021 Jun 30.
Article in English | MEDLINE | ID: mdl-33775766

ABSTRACT

This study aimed to develop a novel electrospun polyacrylonitrile (PAN) nanofiber membrane with the enhanced antibacterial property. The PAN nanofiber membrane was first subjected to alkaline hydrolysis treatment, and the treated membrane was subsequently grafted with chitosan (CS) to obtain a CS-modified nanofiber membrane (P-COOH-CS). The modified membrane was then coupled with different dye molecules to form P-COOH-CS-Dye membranes. Lastly, poly(hexamethylene biguanide) hydrochloride (PHMB) was immobilized on the modified membrane to produce P-COOH-CS-Dye-PHMB. Physical characterization studies were conducted on all the synthesized nanofiber membranes. The antibacterial efficacies of nanofiber membranes prepared under different synthesis conditions were evaluated systematically. Under the optimum synthesis conditions, P-COOH-CS-Dye-PHMB was highly effective in disinfecting a high concentration of Escherichia coli, with an antibacterial efficacy of approximately 100%. Additionally, the P-COOH-CS-Dye-PHMB exhibited an outstanding wash durability as its antibacterial efficacy was only reduced in the range of 5%-7% even after 5 repeated cycles of treatment. Overall, the experimental results of this study suggested that the P-COOH-CS-Dye-PHMB is a promising antibacterial nanofiber membrane that can be adopted in the food, pharmaceutical, and textile industries.


Subject(s)
Anti-Bacterial Agents/pharmacology , Biguanides/pharmacology , Chitosan/chemistry , Coloring Agents/chemistry , Membranes, Artificial , Nanofibers/chemistry , Anti-Bacterial Agents/chemical synthesis , Anti-Bacterial Agents/chemistry , Biguanides/chemical synthesis , Biguanides/chemistry , Escherichia coli/drug effects , Hydrogen-Ion Concentration , Kinetics , Microbial Sensitivity Tests , Spectroscopy, Fourier Transform Infrared
11.
J Phys Condens Matter ; 33(10): 105701, 2021 Mar 10.
Article in English | MEDLINE | ID: mdl-33232942

ABSTRACT

The quantum anomalous Hall effect (QAHE), carrying dissipationless chiral edge states, occurs without any magnetic field. Two main strategies were proposed to host QAHE: the magnetic topological insulator thin films and graphene systems. Only the former one was realized in experiment at low temperature. In this paper, by dealing with the two-dimensional electron gas with an anti-dot lattice, a realistic platform is proposed to host the QAHE with both Chern number [Formula: see text] and [Formula: see text]. Based on the calculation of the Berry curvature integral and spacial wave function, the topological nature of the QAH edge states is well demonstrated. In the QAH region, the conductance shows quantized plateaus and their values are robust against Anderson disorder. In addition, we have also studied the effects of the size and shape of the anti-dot lattice on QAHE and they provide extra manners to adjust the system parameters. Taking the advantages of the well developed micro-manufacture technique in semiconductors, the proposal is experimentally accessible in micro-scale.

12.
Food Chem ; 338: 128144, 2021 Feb 15.
Article in English | MEDLINE | ID: mdl-33092004

ABSTRACT

A weak ion-exchange membrane (P-COOH) was synthesized by alkaline hydrolysis of a polyacrylonitrile nanofiber membrane prepared by electrospinning process. The P-COOH membrane was characterized for its physical properties and its application for purification of lysozyme from chicken egg white was investigated. The lysozyme adsorption efficiency of the P-COOH membrane operating in a stirred cell contactor (Millipore, Model 8010) was evaluated. The effects of key parameters such as the feed concentration, the rotating speed, the flow rate of feed and the operating pressure were studied. The results showed successful purification of lysozyme with a high recovery yield of 98% and a purification factor of 63 in a single step. The purification strategy was scaled-up to the higher feedstock loading volume of 32.7 and 70 mL using stirred cell contactors of Model 8050 and 8200, respectively. The scale-up processes achieved similar purification results, proving linear scalability of the purification technique adopted.


Subject(s)
Chemical Fractionation/instrumentation , Egg White , Membranes, Artificial , Muramidase/isolation & purification , Nanofibers/chemistry , Acrylic Resins/chemistry , Adsorption , Animals , Ion Exchange , Muramidase/chemistry
13.
Chemosphere ; 270: 128615, 2021 May.
Article in English | MEDLINE | ID: mdl-33077189

ABSTRACT

This work studied the potential of using eggshell (ES) (200-300 µm) waste as adsorbent for sequential removal of heavy metals, soluble microbial products, and dye wastes. In this study, among soluble microbial products, chicken egg white (CEW) proteins were selected as simulated contaminants. ES was applied to capture heavy metal ions (e.g., Cu2+ and Zn2+) and the formed eggshell metal (ES-M) complex was use to absorb soluble microbial products (e.g., soluble proteins), followed by subsequent removal of dyes from aqueous solutions using ES-M-CEW adsorbent. The experimental conditions for the adsorption of CEW proteins by ES-M include shaking rate, adsorption pH, isothermal and kinetic studies. The maximum protein adsorption by ES-Zn and ES-Cu were 175.67 and 153.65 mg/g, respectively. Optimal removal efficiencies of the ES-M-CEW particles for Acid Orange (AO7) and Toluidine blue (TBO) dyes were at pH 2 and 12, respectively, achieving performance of 75.38 and 114.18 mg/g, respectively. The removal of TBO dye by ES-M-CEW adsorbent was equilibrated at 5 min. The results showed that low cost and simple preparation of the modified ES particles are feasible for treating various wastewaters.


Subject(s)
Metals, Heavy , Water Pollutants, Chemical , Adsorption , Animals , Coloring Agents , Egg Shell/chemistry , Hydrogen-Ion Concentration , Kinetics , Water Pollutants, Chemical/analysis
14.
Food Chem ; 343: 128543, 2021 May 01.
Article in English | MEDLINE | ID: mdl-33187742

ABSTRACT

Lysozyme from crude chicken egg white (CEW) feedstock was successfully purified using a stirred fluidized bed adsorption system ion exchange chromatography where STREAMLINE SP and SP-XL high density adsorbents were selected as the adsorption carrier. The thermodynamic and kinetic studies were carried out to understand the characteristics of lysozyme adsorption by adsorbents under various conditions, including adsorption pH, temperature, lysozyme concentration and salt concentrations. Results showed that SP and SP-XL adsorbents achieved optimum lysozyme adsorption at pH 9 with capacity of ~139.77 and ~251.26 mg/mL, respectively. The optimal conditions obtained from batch studies were directly employed to operate in SFBA process. For SP-XL adsorbent, the recovery yield and purification factor of lysozyme were 93.78% and ~40 folds, respectively. For SP adsorbent, lysozyme can be eluted ~100% with purification factor of ~26 folds. These two adsorbents are highly suitable for use in direct recovery of lysozyme from crude CEW.


Subject(s)
Chromatography, Ion Exchange/methods , Egg White/chemistry , Muramidase/isolation & purification , Adsorption , Animals , Chickens , Kinetics , Muramidase/chemistry , Temperature
15.
Int J Biol Macromol ; 165(Pt A): 1410-1421, 2020 Dec 15.
Article in English | MEDLINE | ID: mdl-33045299

ABSTRACT

Electrospinning technology was applied for the preparation of polyacrylonitrile (PAN) nanofiber membrane in this work. After hot pressing, alkaline hydrolysis and neutralization treatment, a weak acid cation exchange membrane (P-COOH) was prepared. By the covalent coupling reaction between the acidic membrane and aminomethane sulfonic acid (AMSA), a strong acidic nanofiber membrane (P-SO3H) was obtained. The surface morphology, chemical structure, and thermal stability of the prepared ion exchange membranes were analyzed via SEM, FTIR and TGA. Analytical results showed that the membranes were prepared successfully and thermally stable. The ion exchange membrane (IEX) was conducted with the newly designed membrane reactor, and different operating conditions affecting the adsorption efficiency of Toluidine Blue dye (TBO) were investigated by dynamic flow process. The results showed that dynamic binding capacity (DBC) of weak and strong IEX membranes for TBO dye was ~170 mg/g in a dynamic flow process. Simultaneously, the ion exchange membranes were also used for purifying lysozyme from chicken egg white (CEW). Results illustrated that the recovery yield and purification factor of lysozyme were 93.43% and 29.23 times (P-COOH); 90.72% and 36.22 times (P-SO3H), respectively. It was revealed that two type ion exchange membranes were very suitable as an adsorber for use in dye waste treatment and lysozyme purification process. P-SO3H strong ion-exchange membrane was more effective either removal of TBO dye or purification of lysozyme. The ion exchange membranes not only effectively purified lysozyme from CEW solution, but also effectively removed dye from wastewater.


Subject(s)
Amsacrine/chemistry , Coloring Agents/chemistry , Muramidase/chemistry , Nanofibers/chemistry , Acrylic Resins/chemistry , Adsorption/drug effects , Cations/chemistry , Coloring Agents/isolation & purification , Ion Exchange , Membranes, Artificial , Muramidase/isolation & purification
16.
Int J Biol Macromol ; 164: 4455-4465, 2020 Dec 01.
Article in English | MEDLINE | ID: mdl-32937154

ABSTRACT

A stirred fluidized bed (SFB) ion exchange chromatography was successfully applied in the direct recovery of recombinant enhanced green fluorescent protein (EGFP) from the unclarified Escherichia coli homogenate. Optimal conditions for both adsorption and elution processes were determined from the packed-bed adsorption systems conducted at a small scale using the clarified cell homogenate. The maximal adsorption capacity and dissociation constant for EGFP-adsorbent complex were found to be 6.3 mg/mL and 1.3 × 10-3 mg/mL, respectively. In an optimal elution of EGFP with 0.2 M of NaCl solution (pH 9) and at 200 cm/h, the recovery percent of the EGFP was approximately 93%. The performances of SFB chromatography for direct recovery of EGFP was also evaluated under different loading volumes (50-200 mL) of crude cell homogenate. The single-step purification of EGFP by SFB recorded in a high yield (95-98%) and a satisfactory purification factor (~3 folds) of EGFP from the cell homogenate at 200 rpm of rotating speed.


Subject(s)
Chromatography, Ion Exchange/methods , Escherichia coli/chemistry , Green Fluorescent Proteins/isolation & purification , Recombinant Proteins/isolation & purification , Adsorption , Chromatography, Ion Exchange/instrumentation , Equipment Design , Ethanolamines
17.
Int J Biol Macromol ; 162: 1711-1724, 2020 Nov 01.
Article in English | MEDLINE | ID: mdl-32805284

ABSTRACT

Adsorption of lysozyme on the dye-affinity nanofiber membranes was investigated in batch and dynamic modes. The membrane matrix was made of electrospun polyacrylonitrile nanofibers that were grafted with ethylene diamine (EDA) and/or chitosan (CS) for the coupling of Reactive Blue 49 dye. The physicochemical properties of these dye-immobilized nanofiber membranes (P-EDA-Dye and P-CS-Dye) were characterized microscopically, spectroscopically and thermogravimetrically. The capacities of lysozyme adsorption by the dye-affinity nanofiber membranes were evaluated under various conditions, namely pH, dye immobilized density, and loading flow rate. The adsorption of lysozyme to the dye-affinity nanofiber membranes was well fitted by Langmuir isotherm and pseudo-second kinetic models. P-CS-Dye nanofiber membrane had a better performance in the dynamic adsorption of lysozyme from complex chicken egg white solution. It was observed that after five cycles of adsorption-desorption, the dye-affinity nanofiber membrane did not show a significant loss in its capacity for lysozyme adsorption. The robustness as well as high dynamic adsorption capability of P-CS-Dye nanofiber membrane are promising for the efficient recovery of lysozyme from complex feedstock via nanofiber membrane chromatography.


Subject(s)
Chitosan/chemistry , Chromatography, Affinity , Egg White/chemistry , Ethylenediamines/chemistry , Muramidase/chemistry , Nanofibers/chemistry , Adsorption , Animals , Chickens , Coloring Agents/chemistry , Hydrogen-Ion Concentration , Kinetics , Membranes, Artificial
18.
Food Chem ; 327: 127038, 2020 Oct 15.
Article in English | MEDLINE | ID: mdl-32447136

ABSTRACT

Polyacrylonitrile nanofiber membrane functionalized with tris(hydroxymethyl)aminomethane (P-Tris) was used in affinity membrane chromatography for lysozyme adsorption. The effects of pH and protein concentration on lysozyme adsorption were investigated. Based on Langmuir model, the adsorption capacity of P-Tris nanofiber membrane was estimated to be 345.83 mg/g. For the operation of dynamic membrane chromatography with three-layer P-Tris nanofiber membranes, the optimal operating conditions were at pH 9, 1.0 mL/min of feed flow rate, and 2 mg/mL of feed concentration. Chicken egg white (CEW) was applied as the crude feedstock of lysozyme in the optimized dynamic membrane chromatography. The percent recovery and purification factor of lysozyme obtained from the chromatography were 93.28% and 103.98 folds, respectively. Our findings demonstrated the effectiveness of P-Tris affinity nanofiber membrane for the recovery of lysozyme from complex CEW solution.


Subject(s)
Chromatography, Affinity/methods , Egg White/chemistry , Muramidase/isolation & purification , Nanofibers/chemistry , Tromethamine/chemistry , Adsorption , Membranes, Artificial , Muramidase/chemistry
19.
Int J Biol Macromol ; 154: 844-854, 2020 Jul 01.
Article in English | MEDLINE | ID: mdl-32194127

ABSTRACT

In this study, polyacrylonitrile (PAN) nanofiber membrane was prepared by an electrospinning technique. After alkaline hydrolysis, the ion-exchange nanofiber membrane (P-COOH) was grafted with chitosan molecules to form a chitosan-modified nanofiber membrane (P-COOH-CS). Poly(hexamethylene biguanide) (PHMB) was then covalently immobilized on P-COOH and P-COOH-CS to form P-COOH-PHMB and P-COOH-CS-PHMB, respectively. The nanofiber membranes were subjected to various surface analyses as well as to the evaluations of antibacterial activity against Escherichia coli. The optimal modification conditions for P-COOH-CS-PHMB were attained by water-soluble chitosan at 50 kDa of molecular weight, coupling pH at 7, and 0.05% (w/w) of PHMB. Within 10 min of treatment, the antibacterial rate was close to 100%. Under the similar conditions of antibacterial treatment, the P-COOH-CS-PHMB exhibited a better antibacterial efficacy than the P-COOH-PHMB. When the number of bacterial cells was increased by 2000 folds, both types of nanofiber membranes still maintained the antibacterial rate close to 100%. After five cycles of repeated antibacterial treatment, the antibacterial efficacy of P-COOH-PHMB was 96%, which was higher than that of P-COOH-CS-PHMB (83%). The experimental results revealed that the PHMB-modified nanofiber membranes can be suitably applied in water treatment such as water disinfection and biofouling control.


Subject(s)
Anti-Bacterial Agents , Biguanides/chemistry , Chitosan/chemistry , Nanofibers/chemistry , Anti-Bacterial Agents/chemistry , Anti-Bacterial Agents/pharmacology , Escherichia coli/drug effects , Membranes, Artificial , Water Purification
20.
Theranostics ; 10(8): 3451-3473, 2020.
Article in English | MEDLINE | ID: mdl-32206101

ABSTRACT

While protein arginine methyltransferases (PRMTs) and PRMT-catalyzed protein methylation have been well-known to be involved in a myriad of biological processes, their functions and the underlying molecular mechanisms in cancers, particularly in estrogen receptor alpha (ERα)-positive breast cancers, remain incompletely understood. Here we focused on investigating PRMT4 (also called coactivator associated arginine methyltransferase 1, CARM1) in ERα-positive breast cancers due to its high expression and the associated poor prognosis. Methods: ChIP-seq and RNA-seq were employed to identify the chromatin-binding landscape and transcriptional targets of CARM1, respectively, in the presence of estrogen in ERα-positive MCF7 breast cancer cells. High-resolution mass spectrometry analysis of enriched peptides from anti-monomethyl- and anti-asymmetric dimethyl-arginine antibodies in SILAC labeled wild-type and CARM1 knockout cells were performed to globally map CARM1 methylation substrates. Cell viability was measured by MTS and colony formation assay, and cell cycle was measured by FACS analysis. Cell migration and invasion capacities were examined by wound-healing and trans-well assay, respectively. Xenograft assay was used to analyze tumor growth in vivo. Results: CARM1 was found to be predominantly and specifically recruited to ERα-bound active enhancers and essential for the transcriptional activation of cognate estrogen-induced genes in response to estrogen treatment. Global mapping of CARM1 substrates revealed that CARM1 methylated a large cohort of proteins with diverse biological functions, including regulation of intracellular estrogen receptor-mediated signaling, chromatin organization and chromatin remodeling. A large number of CARM1 substrates were found to be exclusively hypermethylated by CARM1 on a cluster of arginine residues. Exemplified by MED12, hypermethylation of these proteins by CARM1 served as a molecular beacon for recruiting coactivator protein, tudor-domain-containing protein 3 (TDRD3), to CARM1-bound active enhancers to activate estrogen/ERα-target genes. In consistent with its critical role in estrogen/ERα-induced gene transcriptional activation, CARM1 was found to promote cell proliferation of ERα-positive breast cancer cells in vitro and tumor growth in mice. Conclusions: our study uncovered a "hypermethylation" strategy utilized by enhancer-bound CARM1 in gene transcriptional regulation, and suggested that CARM1 can server as a therapeutic target for breast cancer treatment.


Subject(s)
Breast Neoplasms/metabolism , Enhancer Elements, Genetic , Estrogen Receptor alpha/metabolism , Gene Expression Regulation, Neoplastic , Protein-Arginine N-Methyltransferases/metabolism , Animals , Arginine/metabolism , Breast Neoplasms/genetics , Cell Proliferation , Cell Transformation, Neoplastic , Chromatin Immunoprecipitation Sequencing , Estrogens/metabolism , Female , Gene Knockout Techniques , Humans , MCF-7 Cells , Mediator Complex/metabolism , Methylation , Mice , Mice, Inbred BALB C , Mice, Nude , Protein Binding , Protein-Arginine N-Methyltransferases/genetics , Proteins/metabolism , RNA-Seq , Transcriptional Activation , Xenograft Model Antitumor Assays
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