scholarly journals Ion-Imprinted Polypropylene Fibers Fabricated by the Plasma-Mediated Grafting Strategy for Efficient and Selective Adsorption of Cr(VI)

Polymers ◽  
2019 ◽  
Vol 11 (9) ◽  
pp. 1508 ◽  
Author(s):  
Zhengwei Luo ◽  
Jiahuan Xu ◽  
Dongmei Zhu ◽  
Dan Wang ◽  
Jianjian Xu ◽  
...  
Keyword(s):  
Time Pressure ◽  
Discharge Plasma ◽  
Selective Adsorption ◽  
Polypropylene Fibers ◽  
Adsorption Selectivity ◽  
Plasma Irradiation ◽  
Ion Imprinted ◽  
The Stability ◽  
Kinetics Of

To improve the adsorption selectivity towards hexavalent chromium anion (Cr(VI)), surface Cr(VI)-imprinted polypropylene (PP) fibers were fabricated by the plasma-mediated grafting strategy. Hence, a non-thermal Rradio frequency discharge plasma irradiation followed by a gaseous phase grafting was used to load acrylic acid (AA) onto PP fibers, which was afterwards amidated with triethylenetetramine and subjected to imprinting with a Cr(VI) template. The plasma irradiation conditions, i.e., gas species, output power, pressure, and time, were optimized and then the influence of grafting time, pressure, and temperature on the grafting degree of AA was investigated. Scanning electron microscopy and Fourier transform infrared spectroscopy were used for the characterization of pristine and modified fibers and to confirm the synthesis success. The hydrophilicity of modified fibers was greatly improved compared with pristine PP fibers. The adsorption thermodynamics and kinetics of Cr(VI) were investigated, as well as the elution efficiency and reusability. The prepared imprinted fibers showed superior adsorption selectivity to Cr(VI) compared with non-imprinted fibers. Finally, the stability of the imprinted fibers against the oxidation ability of Cr(VI) is discussed.

Preparation and Recognition Performance of Molecularly Imprinted Polymers for Cadmium with Surface-Imprinting Technique

2013 ◽  
Vol 807-809 ◽  
pp. 461-465 ◽  
Author(s):  
Dao Bo Zhou ◽  
En Qi Liu ◽  
Shang Long Chen ◽  
Shi Rong Tang
Keyword(s):  
Adsorption Capacity ◽  
Selective Adsorption ◽  
Recognition Performance ◽  
Kinetic Curve ◽  
Maximum Adsorption Capacity ◽  
Surface Imprinting Technique ◽  
Molecular Imprinting Technology ◽  
Ion Imprinted ◽  
Kinetics Of ◽  
Silica Gel Particles

A new Cd (II) ion-imprinted polymer (Cd (II)-IIP), which can be used for selective adsorption of Cd (II) from aqueous solutions, was successfully prepared based on silica gel particles with the help of surface molecular imprinting technology. The adsorption kinetic curve, adsorption isotherm and selective adsorption were measured by static method. The adsorption kinetics of IIPs for Cd (II) reached the equilibrium at about 10 min. The maximum adsorption capacity was 29.36 mg/g, and the IIPs had much higher adsorption quantity than NIPs. Competitive adsorption studies showed that Cd (II)-IIP offers the advantages of selectivity toward targeted Cd (II) compared with NIP in the presence other metal ions. The results showed that the IIPs possessed good specific adsorption capacity and selectivity for Cd (II).

scholarly journals Characterization of the Global Stabilizing Substitution A77V and Its Role in the Evolution of CTX-M β-Lactamases

2015 ◽  
Vol 59 (11) ◽  
pp. 6741-6748 ◽  
Author(s):  
Meha P. Patel ◽  
Bartlomiej G. Fryszczyn ◽  
Timothy Palzkill
Keyword(s):  
Antibiotic Resistance ◽  
Adaptive Mutation ◽  
Common Mechanism ◽  
Antibiotic Hydrolysis ◽  
The Stability ◽  
Kinetics Of ◽  
M 14

ABSTRACTThe widespread use of oxyimino-cephalosporin antibiotics drives the evolution of the CTX-M family of β-lactamases that hydrolyze these drugs and confer antibiotic resistance. Clinically isolated CTX-M enzymes carrying the P167S or D240G active site-associated adaptive mutation have a broadened substrate profile that includes the oxyimino-cephalosporin antibiotic ceftazidime. The D240G substitution is known to reduce the stability of CTX-M-14 β-lactamase, and the P167S substitution is shown here to also destabilize the enzyme. Proteins are marginally stable entities, and second-site mutations that stabilize the enzyme can offset a loss in stability caused by mutations that enhance enzyme activity. Therefore, the evolution of antibiotic resistance enzymes can be dependent on the acquisition of stabilizing mutations. The A77V substitution is present in CTX-M extended-spectrum β-lactamases (ESBLs) from a number of clinical isolates, suggesting that it may be important in the evolution of antibiotic resistance in this family of β-lactamases. In this study, the effects of the A77V substitution in the CTX-M-14 model enzyme were characterized with regard to the kinetic parameters for antibiotic hydrolysis as well as enzyme expression levelsin vivoand protein stabilityin vitro. The A77V substitution has little effect on the kinetics of oxyimino-cephalosporin hydrolysis, but it stabilizes the CTX-M enzyme and compensates for the loss of stability resulting from the P167S and D240G mutations. The acquisition of global stabilizing mutations, such as A77V, is an important feature in β-lactamase evolution and a common mechanism in protein evolution.

Synthesis and characterization of surface ion-imprinted polymer based on SiO2-coated graphene oxide for selective adsorption of uranium(vi)

RSC Advances ◽  
2015 ◽  
Vol 5 (83) ◽  
pp. 67662-67668 ◽  
Author(s):  
Hu Meng ◽  
Zheng Li ◽  
Fuyin Ma ◽  
Xiaoning Wang ◽  
Wei Zhou ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Selective Adsorption ◽  
Synthesis And Characterization ◽  
Ion Imprinted Polymer ◽  
Imprinted Polymer ◽  
Ion Imprinted

A novel surface ion-imprinted polymer based on graphene oxide was synthesized for the selective adsorption of U(vi).

scholarly journals Functional Characterization of an Anthocyanin Dimalonyltransferase in Maize

Molecules ◽  
2021 ◽  
Vol 26 (7) ◽  
pp. 2020
Author(s):  
Michael Paulsmeyer ◽  
John Juvik
Keyword(s):  
Substrate Specificity ◽  
Structure Function ◽  
Functional Characterization ◽  
Malonyl Coa ◽  
Natural Colorants ◽  
Acylated Anthocyanins ◽  
The Stability ◽  
Kinetics Of ◽  
Insight Into

Anthocyanins are pigments with appealing hues that are currently being used as sources of natural colorants. The interaction of acylation on the stability of anthocyanin molecules has long been known. Maize is an abundant source of malonylglucoside and dimalonylglucoside anthocyanins. The enzyme Aat1 is an anthocyanin acyltransferase known to synthesize the majority of acylated anthocyanins in maize. In this paper, we characterize the substrate specificity and reaction kinetics of Aat1. It was found that Aat1 has anthocyanin 3-O-glucoside dimalonyltransferase activity and is only the second enzyme of this type characterized to this date. Our results indicate that Aat1 can utilize malonyl-CoA; succinyl-CoA and every anthocyanin 3-O-glucoside tested. Results of this study provide insight into the structure–function relations of dimalonyltransferases and give a unique insight into the activity of monocot anthocyanin acyltransferases.

scholarly journals Development and Characterization of a Gene Expression Reporter System for Clostridium acetobutylicumATCC 824

1999 ◽  
Vol 65 (9) ◽  
pp. 3793-3799 ◽  
Author(s):  
Seshu B. Tummala ◽  
Neil E. Welker ◽  
Eleftherios T. Papoutsakis
Keyword(s):  
Gene Expression ◽  
Reporter Gene ◽  
Time Course ◽  
Specific Activity ◽  
Reporter System ◽  
Inhibit Protein Synthesis ◽  
Acetoacetate Decarboxylase ◽  
The Stability ◽  
Kinetics Of

ABSTRACT A gene expression reporter system (pHT3) for Clostridium acetobutylicum ATCC 824 was developed by using thelacZ gene from Thermoanaerobacterium thermosulfurogenes EM1 as the reporter gene. In order to test the reporter system, promoters of three key metabolic pathway genes,ptb (coding for phosphotransbutyrylase), thl(coding for thiolase), and adc (coding for acetoacetate decarboxylase), were cloned upstream of the reporter gene in pHT3 in order to construct vectors pHT4, pHT5, and pHTA, respectively. Detection of β-galactosidase activity in time course studies performed with strains ATCC 824(pHT4), ATCC 824(pHT5), and ATCC 824(pHTA) demonstrated that the reporter gene produced a functional β-galactosidase in C. acetobutylicum. In addition, time course studies revealed differences in the β-galactosidase specific activity profiles of strains ATCC 824(pHT4), ATCC 824(pHT5), and ATCC 824(pHTA), suggesting that the reporter system developed in this study is able to effectively distinguish between different promoters. The stability of the β-galactosidase produced by the reporter gene was also examined with strains ATCC 824(pHT4) and ATCC 824(pHT5) by using chloramphenicol treatment to inhibit protein synthesis. The data indicated that the β-galactosidase produced by the lacZgene from T. thermosulfurogenes EM1 was stable in the exponential phase of growth. In pH-controlled fermentations of ATCC 824(pHT4), the kinetics of β-galactosidase formation from theptb promoter and phosphotransbutyrylase formation from its own autologous promoter were found to be similar.

scholarly journals Synthesis and Characterization of Ion-Imprinted Polymer for Selective Adsorption of Zinc Ions in Aqueous media

2017 ◽  
Vol 29 (6) ◽  
pp. 1229-1234 ◽  
Author(s):  
G. Zuhra Memon ◽  
Sumera Sarwar ◽  
F. Memon ◽  
Muhammad Qasim Samejo ◽  
A.G.M. Vasandani
Keyword(s):  
Selective Adsorption ◽  
Aqueous Media ◽  
Synthesis And Characterization ◽  
Zinc Ions ◽  
Ion Imprinted Polymer ◽  
Imprinted Polymer ◽  
Ion Imprinted
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