Design of molecular imprinted polymers compatible with aqueous environment.

PubMed

Piletska, Elena V; Guerreiro, Antonio R; Romero-Guerra, Maria; Chianella, Iva; Turner, Anthony P F; Piletsky, Sergey A

2008-01-21

The main problem of poor water compatibility of molecularly imprinted polymers (MIPs) was addressed in examples describing design of synthetic receptors with high affinity for drugs of abuse. An extensive potentiometric titration of 10 popular functional monomers and corresponding imprinted and blank polymers was conducted in order to evaluate the subtleties of functional groups ionisation under aqueous conditions. It was found that polymers prepared using 2-trifluoromethacrylic acid (TFMAA) in combination with toluene as porogen possess superior properties which make them suitable for effective template recognition in water. The potential impact of phase separation during polymerisation on formation of high quality imprints has been discussed. Three drugs of abuse such as cocaine, deoxyephedrine and methadone were used as template models in polymer preparation for the practical validation of obtained results. The polymer testing showed that synthesized molecularly imprinted polymers have high affinity and selectivity for corresponding templates in aqueous environment, with imprinting factors of 2.6 for cocaine and 1.4 for methadone and deoxyephedrine. Corresponding blank polymers were unable to differentiate between analytes, suggesting that imprinting phenomenon was responsible for the recognition properties.

Genotype and phenotype in patients with Prader-Willi syndrome in Taiwan.

PubMed

Lin, Hsiang-Yu; Lin, Shuan-Pei; Chuang, Chih-Kuang; Chen, Ming-Ren; Yen, Jui-Lung; Lee, Yann-Jinn; Huang, Chi-Yu; Tsai, Li-Ping; Niu, Dau-Ming; Chao, Mei-Chyn; Kuo, Pao-Lin

2007-06-01

Several different genetic defects have been found to result in the characteristic phenotypic expression of Prader-Willi syndrome (PWS). We performed a retrospective analysis of 67 cases of molecularly confirmed PWS diagnosed from January 1980 through July 2006 in five medical centres in Taiwan. Clinical manifestations were compared between patients with deletion and those with maternal uniparental disomy (UPD). Deletion was present in 56 (84%), UPD in 10 (15%), and a probable imprinting centre deletion or imprinting defect in 1 (1%). PWS with deletion was more likely than that with UPD to be characterized by hypogonadism (p < 0.001), small hands and feet (p < 0.001), and hypopigmentation (p < 0.002). Both maternal (p = 0.015) and paternal age (p = 0.021) were higher in the UPD group. No other clinical features differed significantly different between the two groups. In contrast to most Western populations with a higher incidence of UPD, this study of PWS in Taiwan shows a higher incidence of deletion. There may be subtle phenotypic differences between the UPD and deletion genotypes, but its not clear that these are important clinically.

Demonstration of a neural circuit critical for imprinting behavior in chicks.

PubMed

Nakamori, Tomoharu; Sato, Katsushige; Atoji, Yasuro; Kanamatsu, Tomoyuki; Tanaka, Kohichi; Ohki-Hamazaki, Hiroko

2010-03-24

Imprinting behavior in birds is elicited by visual and/or auditory cues. It has been demonstrated previously that visual cues are recognized and processed in the visual Wulst (VW), and imprinting memory is stored in the intermediate medial mesopallium (IMM) of the telencephalon. Alteration of neural responses in these two regions according to imprinting has been reported, yet direct evidence of the neural circuit linking these two regions is lacking. Thus, it remains unclear how memory is formed and expressed in this circuit. Here, we present anatomical as well as physiological evidence of the neural circuit connecting the VW and IMM and show that imprinting training during the critical period strengthens and refines this circuit. A functional connection established by imprint training resulted in an imprinting behavior. After the closure of the critical period, training could not activate this circuit nor induce the imprinting behavior. Glutamatergic neurons in the ventroposterior region of the VW, the core region of the hyperpallium densocellulare (HDCo), sent their axons to the periventricular part of the HD, just dorsal and afferent to the IMM. We found that the HDCo is important in imprinting behavior. The refinement and/or enhancement of this neural circuit are attributed to increased activity of HDCo cells, and the activity depended on NR2B-containing NMDA receptors. These findings show a neural connection in the telencephalon in Aves and demonstrate that NR2B function is indispensable for the plasticity of HDCo cells, which are key mediators of imprinting.

Efficient synthesis of molecularly imprinted polymers with bio-recognition sites for the selective separation of bovine hemoglobin.

PubMed

Zhang, Zulei; Li, Lei

2018-06-01

We developed a facile approach to the construction of bio-recognition sites in silica nanoparticles for efficient separation of bovine hemoglobin based on amino-functionalized silica nanoparticles grafting by 3-aminopropyltriethoxylsilane providing hydrogen bonds with bovine hemoglobin through surface molecularly imprinting technology. The resulting amino-functionalized silica surface molecularly imprinted polymers were characterized using scanning electron microscope, transmission electronic microscopy, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and thermogravimetric analysis. Results showed that the as-synthesized imprinted polymers exhibited spherical morphology and favorable thermal stability. The binding adsorption experiments showed that the imprinted polymers can reach equilibrium within 1 h. The Langmuir isotherm and pseudo-second-order kinetic model fitted the adsorption data well. Meanwhile, the imprinted polymers possessed a maximum binding capacity up to 90.3 mg/g and highly selectivity for the recognition of bovine hemoglobin. Moreover, such high binding capacity and selectivity retained after eight cycles, indicating the good stability and reusability of the imprinted polymers. Finally, successful application in the selective recognition of bovine hemoglobin from a real bovine blood sample indicated that the imprinted polymers displayed great potentials in efficient purification and separation of target proteins. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Thermal preparation of lysozyme-imprinted microspheres by using ionic liquid as a stabilizer.

PubMed

Qian, Li-Wei; Hu, Xiao-Ling; Guan, Ping; Gao, Bo; Wang, Dan; Wang, Chao-Li; Li, Ji; Du, Chun-Bao; Song, Wen-Qi

2014-11-01

Thermal preparation of lysozyme-imprinted microspheres was firstly investigated by using biocompatible ionic liquid (IL) as a thermal stabilizer. The imprinted microspheres made with IL could obtain the good recognition ability to template protein, whereas the imprinted polymer synthesized in the absence of it had a similar adsorption capacity to the non-imprinted one. Furthermore, the preparation conditions of imprinted polymers (MIPs) including the content of IL, temperature of polymerization, and types of functional monomers and crosslinkers were systematically analyzed via circular dichroism spectrum and activity assay. The results illustrated that using hydroxyethyl acrylate as the functional monomer, ethylene glycol dimethacrylate as the crosslinker, 5 % IL as the stabilizer, and 75 °C as the reaction temperature could retain the structure of template protein as much as possible. The obtained MIPs showed excellent recognition ability to the template protein with the separation factor and selectivity factor value of 4.30 and 2.21, respectively. Consequently, it is an effective way to accurately imprint and separate template protein by cooperatively using circular dichroism spectroscopy and activity assay during the preparation of protein MIPs. The method of utilizing IL to stabilizing protein at high temperature would offer a good opportunity for various technologies to improve the development of macromolecules imprinting.

Facile and green preparation of novel adsorption materials by combining sol-gel with ion imprinting technology for selective removal of Cu(II) ions from aqueous solution

NASA Astrophysics Data System (ADS)

Ren, Zhongqi; Zhu, Xinyan; Du, Jian; Kong, Delong; Wang, Nian; Wang, Zhuo; Wang, Qi; Liu, Wei; Li, Qunsheng; Zhou, Zhiyong

2018-03-01

A novel green adsorption polymer was prepared by ion imprinted technology in conjunction with sol-gel process under mild conditions for the selective removal of Cu(II) ions from aqueous solution. Effects of preparation conditions on adsorption performance of prepared polymers were studied. The ion-imprinted polymer was prepared using Cu(II) ion as template, N-[3-(2-aminoethylamino) propyl] trimethoxysilane (AAPTMS) as functional monomer and tetraethyl orthosilicate (TEOS) as cross-linker. Water was used as solvent in the whole preparation process. The imprinted and non-imprinted polymers were characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), scanning electron microscope (SEM), atomic force microscope (AFM), Brunauer, Emmett and Teller (BET) and zeta potential. Three-dimensional network structure was formed and functional monomer was successfully cross-linked into the network structure of polymers. Effects of adsorption conditions on adsorption performance of prepared polymers were studied too. The pH value is of great influence on adsorption behavior. Adsorption by ion-imprinted polymer was fast (adsorption equilibrium was reached within 60 min). The adsorption capacity of Cu(II) ion-imprinted polymer was always larger than that of non-imprinted polymer. Pseudo-second-order kinetics model and Freundlich isotherm model fitted well with adsorption data. The maximum adsorption capacity of Cu(II) ion-imprinted polymer was 39.82 mg·g-1. However, the preparation conditions used in this work are much milder than those reported in literatures. The Cu(II) ion-imprinted polymer showed high selectivity and relative selectivity coefficients for Pb(II), Ni(II), Cd(II) and Co(II). In addition, the prepared ion-imprinted polymer could be reused several times without significant loss of adsorption capacity.

The syntheses and characterization of molecularly imprinted polymers for the controlled release of bromhexine.

PubMed

Azodi-Deilami, Saman; Abdouss, Majid; Javanbakht, Mehran

2011-05-01

Imprinted polymers are now being increasingly considered for active biomedical uses such as drug delivery. In this work, the use of molecularly imprinted polymers (MIPs) in designing new drug delivery devices was studied. Imprinted polymers were prepared from methacrylic acid (functional monomer), ethylene glycol dimethacrylate (cross-linker), and bromhexine (as a drug template) using bulk polymerization method. The influence of the template/functional monomer proportion and pH on the achievement of MIPs with pore cavities with a high enough affinity for the drug was investigated. The polymeric devices were further characterized by FT-IR, thermogravimetric analysis, scanning electron microscopy, and binding experiments. The imprinted polymers showed a higher affinity for bromhexine and a slower release rate than the non-imprinted polymers. The controlled release of bromhexine from the prepared imprinted polymers was investigated through in vitro dissolution tests by measuring absorbance at λ (max) of 310 nm by HPLC-UV. The dissolution media employed were hydrochloric acid at the pH level of 3.0 and phosphate buffers, at pH levels of 6.0 and 8.0, maintained at 37.0 and 25.0 ± 0.5 °C. Results from the analyses showed the ability of MIP polymers to control the release of bromhexine In all cases The imprinted polymers showed a higher affinity for bromhexine and a slower release rate than the non-imprinted polymers. At the pH level of 3.0 and at the temperature of 25 °C, slower release of bromhexine imprinted polymer occurred.

Preparation of molecularly imprinted polymers for strychnine by precipitation polymerization and multistep swelling and polymerization and their application for the selective extraction of strychnine from nux-vomica extract powder.

PubMed

Nakamura, Yukari; Matsunaga, Hisami; Haginaka, Jun

2016-04-01

Monodisperse molecularly imprinted polymers for strychnine were prepared by precipitation polymerization and multistep swelling and polymerization, respectively. In precipitation polymerization, methacrylic acid and divinylbenzene were used as a functional monomer and crosslinker, respectively, while in multistep swelling and polymerization, methacrylic acid and ethylene glycol dimethacrylate were used as a functional monomer and crosslinker, respectively. The retention and molecular recognition properties of the molecularly imprinted polymers prepared by both methods for strychnine were evaluated using a mixture of sodium phosphate buffer and acetonitrile as a mobile phase by liquid chromatography. In addition to shape recognition, ionic and hydrophobic interactions could affect the retention of strychnine in low acetonitrile content. Furthermore, molecularly imprinted polymers prepared by both methods could selectively recognize strychnine among solutes tested. The retention factors and imprinting factors of strychnine on the molecularly imprinted polymer prepared by precipitation polymerization were 220 and 58, respectively, using 20 mM sodium phosphate buffer (pH 6.0)/acetonitrile (50:50, v/v) as a mobile phase, and those on the molecularly imprinted polymer prepared by multistep swelling and polymerization were 73 and 4.5. These results indicate that precipitation polymerization is suitable for the preparation of a molecularly imprinted polymer for strychnine. Furthermore, the molecularly imprinted polymer could be successfully applied for selective extraction of strychnine in nux-vomica extract powder. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Molecularly imprinted electrochemical sensing interface based on in-situ-polymerization of amino-functionalized ionic liquid for specific recognition of bovine serum albumin.

PubMed

Wang, Yanying; Han, Miao; Liu, Guishen; Hou, Xiaodong; Huang, Yina; Wu, Kangbing; Li, Chunya

2015-12-15

A molecularly imprinted polymer film was in situ polymerized on a carboxyl functionalized multi-walled carbon nanotubes modified glassy carbon electrode surface under room temperature. This technique provides a promising imprinting approach for protein in an aqueous solution using 3-(3-aminopropyl)-1-vinylimidazolium tetrafluoroborate ionic liquid as functional monomer, N, N'-methylenebisacrylamide as crossing linker, ammonium persulfate and N,N,N',N'-tetramethylethylenediamine as initiator, and bovine serum albumin (BSA) as template. The molecularly imprinted polymerized ionic liquid film shows enhanced accessibility, high specificity and sensitivity towards BSA. Electrochemical sensing performance of the imprinted sensor was thoroughly investigated using K3Fe[CN]6/K4Fe[CN]6 as electroactive probes. Under optimal conditions, the current difference before and after specific recognition of BSA was found linearly related to its concentration in the range from 1.50×10(-9) to 1.50×10(-6) mol L(-1). The detection limit was calculated to be 3.91×10(-10) mol L(-1) (S/N=3). The practical application of the imprinted sensor was demonstrated by determining BSA in liquid milk samples. Copyright © 2015 Elsevier B.V. All rights reserved.

Artificial receptor-functionalized nanoshell: facile preparation, fast separation and specific protein recognition

NASA Astrophysics Data System (ADS)

Ouyang, Ruizhuo; Lei, Jianping; Ju, Huangxian

2010-05-01

This work combined molecular imprinting technology with superparamagnetic nanospheres as the core to prepare artificial receptor-functionalized magnetic nanoparticles for separation of homologous proteins. Using dopamine as a functional monomer, novel surface protein-imprinted superparamagnetic polydopamine (PDA) core-shell nanoparticles were successfully prepared in physiological conditions, which could maintain the natural structure of a protein template and achieved the development of molecularly imprinted polymers (MIPs) from one dimension to zero dimension for efficient recognition towards large biomolecules. The resultant nanoparticles could be used for convenient magnetic separation of homologous proteins with high specificity. The nanoparticles possessed good monodispersibility, uniform surface morphology and high saturation magnetization value. The bound amounts of template proteins measured by both indirect and direct methods were in good agreement. The maximum number of imprinted cavities on the surface of the bovine hemoglobin (Hb)-imprinted nanoshell was 2.21 × 1018 g - 1, which well matched their maximum binding capacity toward bovine Hb. Both the simple method for preparation of MIPs and the magnetic nanospheres showed good application potential in fast separation, effective concentration and selective biosensing of large protein molecules.

Differential regulation of genomic imprinting by TET proteins in embryonic stem cells.

PubMed

Liu, Lizhi; Mao, Shi-Qing; Ray, Chelsea; Zhang, Yu; Bell, Fong T; Ng, Sheau-Fang; Xu, Guo-Liang; Li, Xiajun

2015-09-01

TET proteins have been found to play an important role in active demethylation at CpG sites in mammals. There are some reports implicating their functions in removal of DNA methylation imprint at the imprinted regions in the germline. However, it is not well established whether TET proteins can also be involved in demethylation of DNA methylation imprint in embryonic stem (ES) cells. Here we report that loss of TET proteins caused a significant increase in DNA methylation at the Igf2-H19 imprinted region in ES cells. We also observed a variable increase in DNA methylation at the Peg1 imprinted region in the ES clones devoid of TET proteins, in particular in the differentiated ES cells. By contrast, we did not observe a significant increase of DNA methylation imprint at the Peg3, Snrpn and Dlk1-Dio3 imprinted regions in ES cells lacking TET proteins. Interestingly, loss of TET proteins did not result in a significant increase of DNA methylation imprint at the Igf2-H19 and Peg1 imprinted regions in the embryoid bodies (EB). Therefore, TET proteins seem to be differentially involved in maintaining DNA methylation imprint at a subset of imprinted regions in ES cells and EBs. Copyright © 2015 The Authors. Published by Elsevier B.V. All rights reserved.

An Unbiased Assessment of the Role of Imprinted Genes in an Intergenerational Model of Developmental Programming

PubMed Central

Radford, Elizabeth J.; Isganaitis, Elvira; Jimenez-Chillaron, Josep; Schroeder, Joshua; Molla, Michael; Andrews, Simon; Didier, Nathalie; Charalambous, Marika; McEwen, Kirsten; Marazzi, Giovanna; Sassoon, David; Patti, Mary-Elizabeth; Ferguson-Smith, Anne C.

2012-01-01

Environmental factors during early life are critical for the later metabolic health of the individual and of future progeny. In our obesogenic environment, it is of great socioeconomic importance to investigate the mechanisms that contribute to the risk of metabolic ill health. Imprinted genes, a class of functionally mono-allelic genes critical for early growth and metabolic axis development, have been proposed to be uniquely susceptible to environmental change. Furthermore, it has also been suggested that perturbation of the epigenetic reprogramming of imprinting control regions (ICRs) may play a role in phenotypic heritability following early life insults. Alternatively, the presence of multiple layers of epigenetic regulation may in fact protect imprinted genes from such perturbation. Unbiased investigation of these alternative hypotheses requires assessment of imprinted gene expression in the context of the response of the whole transcriptome to environmental assault. We therefore analyse the role of imprinted genes in multiple tissues in two affected generations of an established murine model of the developmental origins of health and disease using microarrays and quantitative RT–PCR. We demonstrate that, despite the functional mono-allelicism of imprinted genes and their unique mechanisms of epigenetic dosage control, imprinted genes as a class are neither more susceptible nor protected from expression perturbation induced by maternal undernutrition in either the F1 or the F2 generation compared to other genes. Nor do we find any evidence that the epigenetic reprogramming of ICRs in the germline is susceptible to nutritional restriction. However, we propose that those imprinted genes that are affected may play important roles in the foetal response to undernutrition and potentially its long-term sequelae. We suggest that recently described instances of dosage regulation by relaxation of imprinting are rare and likely to be highly regulated. PMID:22511876

Synthesis and characterization of MAA-based molecularly-imprinted polymer (MIP) with D-glucose template

NASA Astrophysics Data System (ADS)

Yanti; Nurhayati, T.; Royani, I.; Widayani; Khairurrijal

2016-08-01

In this study, molecularly-imprinted polymer (MIP) was prepared by using a D-glucose template and a methacrylic acid (MAA) functional monomer. The obtained MIP was characterized using X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy techniques to study the template imprinting results. For comparison, similar characterizations were also carried out for the respective non imprinted polymer (NIP). It was found that the polymer has semicrystalline structure, with crystallinity degree of the unleached- polymer, the NIP, and the MIP is 62.40%, 62.97%, and 63.47%, respectively. XRD patterns showed that the intensity peaks increases as D-glucose content decreases. The FTIR spectra of the MIP indicate the detail interaction of template and functional monomer.

Detection of HIT antibody dependent platelet aggregation using novel surface imprinting approach.

PubMed

Hussain, Munawar; Northoff, Hinnak; Gehring, Frank K

2016-01-15

We present a fast, robust and straightforward spin force assisted surface imprinting approach for activated platelets and demonstrate that Heparin induced thrombocytopenia (HIT) platelet aggregation can be measured by this approach. A critical and challenging step in functional assays for HIT is platelet separation from the healthy donor's platelet-rich plasma (PRP). Our approach using surface imprinted polymer (MIP) for measurements on a quartz crystal microbalance with dissipation (QCM-D) enables monitoring of platelet aggregation directly in PRP thus eliminating the challenge of platelet separation. This is the first report of platelet imprinting. We also provide proof of principle that QCM-D technology can be applied for functional measurements of HIT antibodies. Copyright © 2015 Elsevier B.V. All rights reserved.

A Survey for Novel Imprinted Genes in the Mouse Placenta by mRNA-seq

PubMed Central

Wang, Xu; Soloway, Paul D.; Clark, Andrew G.

2011-01-01

Many questions about the regulation, functional specialization, computational prediction, and evolution of genomic imprinting would be better addressed by having an exhaustive genome-wide catalog of genes that display parent-of-origin differential expression. As a first-pass scan for novel imprinted genes, we performed mRNA-seq experiments on embryonic day 17.5 (E17.5) mouse placenta cDNA samples from reciprocal cross F1 progeny of AKR and PWD mouse strains and quantified the allele-specific expression and the degree of parent-of-origin allelic imbalance. We confirmed the imprinting status of 23 known imprinted genes in the placenta and found that 12 genes reported previously to be imprinted in other tissues are also imprinted in mouse placenta. Through a well-replicated design using an orthogonal allelic-expression technology, we verified 5 novel imprinted genes that were not previously known to be imprinted in mouse (Pde10, Phf17, Phactr2, Zfp64, and Htra3). Our data suggest that most of the strongly imprinted genes have already been identified, at least in the placenta, and that evidence supports perhaps 100 additional weakly imprinted genes. Despite previous appearance that the placenta tends to display an excess of maternally expressed imprinted genes, with the addition of our validated set of placenta-imprinted genes, this maternal bias has disappeared. PMID:21705755

Functional Genomic Approaches for the Study of Fetal/Placental Development in Swine with Special Emphasis on Imprinted Genes

USDA-ARS?s Scientific Manuscript database

The overall focus of this chapter will be the application of functional genomic approaches for the study of the imprinted gene family in swine. While there are varied definitions of “functional genomics” in general they focus on the application of genomic approaches such as DNA microarrays, single n...

Molecular function of microtubule-associated protein 2 for filial imprinting in domestic chicks (Gallus gallus domesticus).

PubMed

Yamaguchi, Shinji; Katagiri, Sachiko; Aoki, Naoya; Iikubo, Eiji; Kitajima, Takaaki; Matsushima, Toshiya; Homma, Koichi J

2011-01-01

RNA interference (RNAi)-mediated gene-silencing can be a tool for elucidating the role of genes in the neural basis of behavioral plasticity. Previously, we reported that exogenous DNA could be successfully delivered into newly-hatched chick brains via electroporation. Here, we used this in vivo gene-transfer technique and showed that transfected microRNA vectors preferentially silence exogenous DNA expression in neuronal cells. Using this system, the up-regulation of microtubule-associated protein 2 (MAP2) accompanying filial imprinting was suppressed in vivo, which impaired the filial imprinting in chicks. In addition, the phosphorylation of MAP2 was found to increase in parallel with filial imprinting, and lithium chloride, an inhibitor of glycogen synthase kinase 3 (GSK3), was found to impair filial imprinting. Our results suggest that the regulation of MAP2 expression and its phosphorylation are required for filial imprinting and may modify microtubule stability, thereby leading to cytoskeletal reorganization during imprinting. This in vivo RNAi-mediated gene-silencing system will facilitate the analysis of gene function in the living chick brain and provides further clues regarding the molecular mechanisms underpinning avian learning. Copyright © 2010 Elsevier Ireland Ltd and the Japan Neuroscience Society. All rights reserved.

Verification of epigenetic inheritance in a unicellular model system: multigenerational effects of hormonal imprinting.

PubMed

Kőhidai, László; Lajkó, Eszter; Pállinger, Eva; Csaba, György

2012-10-01

The unicellular Tetrahymena has receptors for hormones of higher vertebrates, produces these hormones, and their signal pathways are similar. The first encounter with a hormone in higher dose provokes the phenomenon of hormonal imprinting, by which the reaction of the cell is quantitatively modified. This modification is transmitted to the progeny generations. The duration of the single imprinter effect of two representative signal molecules, insulin and 5-HT (5-hydroxytryptamine), in two concentrations (10(-6) and 10(-15) M) were studied. The effects of imprinting were followed in 5 physiological indices: (i) insulin binding, (ii) 5-HT synthesis, (iii) swimming behaviour, (iv) cell growth and (v) chemotaxis in progeny generations 500 and 1000. The result of each index was different from the non-imprinted control functions, growth rate, swimming behaviour and chemotactic activity to insulin being enhanced, while others, e.g. synthesis and chemotactic responsiveness of 5-HT and the binding of insulin were reduced. This means that a function-specific heritable epigenetic change during imprinting occurs, and generally a single encounter with a femtomolar hormone concentration is enough for provoking durable and heritable imprinting in Tetrahymena. The experiments demonstrate the possibility of epigenetic effects at a unicellular level and call attention to the possibility that the character of unicellular organisms has changed through to the present day due to an enormous amount of non-physiological imprinter substances in their environment. The results - together with results obtained earlier in mammals - point to the validity of epigenetic imprinting effects throughout the animal world.

Separation and determination of citrinin in corn using HPLC fluorescence detection assisted by molecularly imprinted solid phase extraction clean-up

USDA-ARS?s Scientific Manuscript database

A liquid chromatography based method to detect citrinin in corn was developed using molecularly imprinted solid phase extraction (MISPE) sample clean-up. Molecularly imprinted polymers were synthesized using 1,4-dihydroxy-2-naphthoic acid as the template and an amine functional monomer. Density func...

Neuronal plasticity and multisensory integration in filial imprinting.

PubMed

Town, Stephen Michael; McCabe, Brian John

2011-03-10

Many organisms sample their environment through multiple sensory systems and the integration of multisensory information enhances learning. However, the mechanisms underlying multisensory memory formation and their similarity to unisensory mechanisms remain unclear. Filial imprinting is one example in which experience is multisensory, and the mechanisms of unisensory neuronal plasticity are well established. We investigated the storage of audiovisual information through experience by comparing the activity of neurons in the intermediate and medial mesopallium of imprinted and naïve domestic chicks (Gallus gallus domesticus) in response to an audiovisual imprinting stimulus and novel object and their auditory and visual components. We find that imprinting enhanced the mean response magnitude of neurons to unisensory but not multisensory stimuli. Furthermore, imprinting enhanced responses to incongruent audiovisual stimuli comprised of mismatched auditory and visual components. Our results suggest that the effects of imprinting on the unisensory and multisensory responsiveness of IMM neurons differ and that IMM neurons may function to detect unexpected deviations from the audiovisual imprinting stimulus.

Neuronal Plasticity and Multisensory Integration in Filial Imprinting

PubMed Central

Town, Stephen Michael; McCabe, Brian John

2011-01-01

Many organisms sample their environment through multiple sensory systems and the integration of multisensory information enhances learning. However, the mechanisms underlying multisensory memory formation and their similarity to unisensory mechanisms remain unclear. Filial imprinting is one example in which experience is multisensory, and the mechanisms of unisensory neuronal plasticity are well established. We investigated the storage of audiovisual information through experience by comparing the activity of neurons in the intermediate and medial mesopallium of imprinted and naïve domestic chicks (Gallus gallus domesticus) in response to an audiovisual imprinting stimulus and novel object and their auditory and visual components. We find that imprinting enhanced the mean response magnitude of neurons to unisensory but not multisensory stimuli. Furthermore, imprinting enhanced responses to incongruent audiovisual stimuli comprised of mismatched auditory and visual components. Our results suggest that the effects of imprinting on the unisensory and multisensory responsiveness of IMM neurons differ and that IMM neurons may function to detect unexpected deviations from the audiovisual imprinting stimulus. PMID:21423770

Sexual dimorphism in parental imprint ontogeny and contribution to embryonic development.

PubMed

Bourc'his, Déborah; Proudhon, Charlotte

2008-01-30

Genomic imprinting refers to the functional non-equivalence of parental genomes in mammals that results from the parent-of-origin allelic expression of a subset of genes. Parent-specific expression is dependent on the germ line acquisition of DNA methylation marks at imprinting control regions (ICRs), coordinated by the DNA-methyltransferase homolog DNMT3L. We discuss here how the gender-specific stages of DNMT3L expression may have influenced the various sexually dimorphic aspects of genomic imprinting: (1) the differential developmental timing of methylation establishment at paternally and maternally imprinted genes in each parental germ line, (2) the differential dependence on DNMT3L of parental methylation imprint establishment, (3) the unequal duration of paternal versus maternal methylation imprints during germ cell development, (4) the biased distribution of methylation-dependent ICRs towards the maternal genome, (5) the different genomic organization of paternal versus maternal ICRs, and finally (6) the overwhelming contribution of maternal germ line imprints to development compared to their paternal counterparts.

Synthesis of molecular imprinting polymers for extraction of gallic acid from urine.

PubMed

Bhawani, Showkat Ahmad; Sen, Tham Soon; Ibrahim, Mohammad Nasir Mohammad

2018-02-21

The molecularly imprinted polymers for gallic acid were synthesized by precipitation polymerization. During the process of synthesis a non-covalent approach was used for the interaction of template and monomer. In the polymerization process, gallic acid was used as a template, acrylic acid as a functional monomer, ethylene glycol dimethacrylate as a cross-linker and 2,2'-azobisisobutyronitrile as an initiator and acetonitrile as a solvent. The synthesized imprinted and non-imprinted polymer particles were characterized by using Fourier-transform infrared spectroscopy and scanning electron microscopy. The rebinding efficiency of synthesized polymer particles was evaluated by batch binding assay. The highly selective imprinted polymer for gallic acid was MIPI1 with a composition (molar ratio) of 1:4:20, template: monomer: cross-linker, respectively. The MIPI1 showed highest binding efficiency (79.50%) as compared to other imprinted and non-imprinted polymers. The highly selective imprinted polymers have successfully extracted about 80% of gallic acid from spiked urine sample.

The parental non-equivalence of imprinting control regions during mammalian development and evolution.

PubMed

Schulz, Reiner; Proudhon, Charlotte; Bestor, Timothy H; Woodfine, Kathryn; Lin, Chyuan-Sheng; Lin, Shau-Ping; Prissette, Marine; Oakey, Rebecca J; Bourc'his, Déborah

2010-11-18

In mammals, imprinted gene expression results from the sex-specific methylation of imprinted control regions (ICRs) in the parental germlines. Imprinting is linked to therian reproduction, that is, the placenta and imprinting emerged at roughly the same time and potentially co-evolved. We assessed the transcriptome-wide and ontology effect of maternally versus paternally methylated ICRs at the developmental stage of setting of the chorioallantoic placenta in the mouse (8.5dpc), using two models of imprinting deficiency including completely imprint-free embryos. Paternal and maternal imprints have a similar quantitative impact on the embryonic transcriptome. However, transcriptional effects of maternal ICRs are qualitatively focused on the fetal-maternal interface, while paternal ICRs weakly affect non-convergent biological processes, with little consequence for viability at 8.5dpc. Moreover, genes regulated by maternal ICRs indirectly influence genes regulated by paternal ICRs, while the reverse is not observed. The functional dominance of maternal imprints over early embryonic development is potentially linked to selection pressures favoring methylation-dependent control of maternal over paternal ICRs. We previously hypothesized that the different methylation histories of ICRs in the maternal versus the paternal germlines may have put paternal ICRs under higher mutational pressure to lose CpGs by deamination. Using comparative genomics of 17 extant mammalian species, we show here that, while ICRs in general have been constrained to maintain more CpGs than non-imprinted sequences, the rate of CpG loss at paternal ICRs has indeed been higher than at maternal ICRs during evolution. In fact, maternal ICRs, which have the characteristics of CpG-rich promoters, have gained CpGs compared to non-imprinted CpG-rich promoters. Thus, the numerical and, during early embryonic development, functional dominance of maternal ICRs can be explained as the consequence of two orthogonal evolutionary forces: pressure to tightly regulate genes affecting the fetal-maternal interface and pressure to avoid the mutagenic environment of the paternal germline.

The Parental Non-Equivalence of Imprinting Control Regions during Mammalian Development and Evolution

PubMed Central

Bestor, Timothy H.; Woodfine, Kathryn; Lin, Chyuan-Sheng; Lin, Shau-Ping; Prissette, Marine; Oakey, Rebecca J.; Bourc'his, Déborah

2010-01-01

In mammals, imprinted gene expression results from the sex-specific methylation of imprinted control regions (ICRs) in the parental germlines. Imprinting is linked to therian reproduction, that is, the placenta and imprinting emerged at roughly the same time and potentially co-evolved. We assessed the transcriptome-wide and ontology effect of maternally versus paternally methylated ICRs at the developmental stage of setting of the chorioallantoic placenta in the mouse (8.5dpc), using two models of imprinting deficiency including completely imprint-free embryos. Paternal and maternal imprints have a similar quantitative impact on the embryonic transcriptome. However, transcriptional effects of maternal ICRs are qualitatively focused on the fetal-maternal interface, while paternal ICRs weakly affect non-convergent biological processes, with little consequence for viability at 8.5dpc. Moreover, genes regulated by maternal ICRs indirectly influence genes regulated by paternal ICRs, while the reverse is not observed. The functional dominance of maternal imprints over early embryonic development is potentially linked to selection pressures favoring methylation-dependent control of maternal over paternal ICRs. We previously hypothesized that the different methylation histories of ICRs in the maternal versus the paternal germlines may have put paternal ICRs under higher mutational pressure to lose CpGs by deamination. Using comparative genomics of 17 extant mammalian species, we show here that, while ICRs in general have been constrained to maintain more CpGs than non-imprinted sequences, the rate of CpG loss at paternal ICRs has indeed been higher than at maternal ICRs during evolution. In fact, maternal ICRs, which have the characteristics of CpG-rich promoters, have gained CpGs compared to non-imprinted CpG-rich promoters. Thus, the numerical and, during early embryonic development, functional dominance of maternal ICRs can be explained as the consequence of two orthogonal evolutionary forces: pressure to tightly regulate genes affecting the fetal-maternal interface and pressure to avoid the mutagenic environment of the paternal germline. PMID:21124941

Molecular Imprinting of Macromolecules for Sensor Applications

PubMed Central

Saylan, Yeşeren; Yilmaz, Fatma; Özgür, Erdoğan; Derazshamshir, Ali; Yavuz, Handan; Denizli, Adil

2017-01-01

Molecular recognition has an important role in numerous living systems. One of the most important molecular recognition methods is molecular imprinting, which allows host compounds to recognize and detect several molecules rapidly, sensitively and selectively. Compared to natural systems, molecular imprinting methods have some important features such as low cost, robustness, high recognition ability and long term durability which allows molecularly imprinted polymers to be used in various biotechnological applications, such as chromatography, drug delivery, nanotechnology, and sensor technology. Sensors are important tools because of their ability to figure out a potentially large number of analytical difficulties in various areas with different macromolecular targets. Proteins, enzymes, nucleic acids, antibodies, viruses and cells are defined as macromolecules that have wide range of functions are very important. Thus, macromolecules detection has gained great attention in concerning the improvement in most of the studies. The applications of macromolecule imprinted sensors will have a spacious exploration according to the low cost, high specificity and stability. In this review, macromolecules for molecularly imprinted sensor applications are structured according to the definition of molecular imprinting methods, developments in macromolecular imprinting methods, macromolecular imprinted sensors, and conclusions and future perspectives. This chapter follows the latter strategies and focuses on the applications of macromolecular imprinted sensors. This allows discussion on how sensor strategy is brought to solve the macromolecules imprinting. PMID:28422082

Molecular Imprinting of Macromolecules for Sensor Applications.

PubMed

Saylan, Yeşeren; Yilmaz, Fatma; Özgür, Erdoğan; Derazshamshir, Ali; Yavuz, Handan; Denizli, Adil

2017-04-19

Molecular recognition has an important role in numerous living systems. One of the most important molecular recognition methods is molecular imprinting, which allows host compounds to recognize and detect several molecules rapidly, sensitively and selectively. Compared to natural systems, molecular imprinting methods have some important features such as low cost, robustness, high recognition ability and long term durability which allows molecularly imprinted polymers to be used in various biotechnological applications, such as chromatography, drug delivery, nanotechnology, and sensor technology. Sensors are important tools because of their ability to figure out a potentially large number of analytical difficulties in various areas with different macromolecular targets. Proteins, enzymes, nucleic acids, antibodies, viruses and cells are defined as macromolecules that have wide range of functions are very important. Thus, macromolecules detection has gained great attention in concerning the improvement in most of the studies. The applications of macromolecule imprinted sensors will have a spacious exploration according to the low cost, high specificity and stability. In this review, macromolecules for molecularly imprinted sensor applications are structured according to the definition of molecular imprinting methods, developments in macromolecular imprinting methods, macromolecular imprinted sensors, and conclusions and future perspectives. This chapter follows the latter strategies and focuses on the applications of macromolecular imprinted sensors. This allows discussion on how sensor strategy is brought to solve the macromolecules imprinting.

Rapid Birth-and-Death Evolution of Imprinted snoRNAs in the Prader-Willi Syndrome Locus: Implications for Neural Development in Euarchontoglires

PubMed Central

Zhang, Yi-Jun; Yang, Jian-Hua; Shi, Qiao-Su; Zheng, Ling-Ling; Liu, Jun; Zhou, Hui; Zhang, Hui; Qu, Liang-Hu

2014-01-01

Imprinted small nucleolar RNAs (snoRNAs) are only found in eutherian genomes and closely related to brain functions. A complex human neurological disease, Prader-Willi syndrome (PWS), is primarily attributed to the deletion of imprinted snoRNAs in chromosome 15q11-q13. Here we investigated the snoRNA repertoires in the PWS locus of 12 mammalian genomes and their evolution processes. A total of 613 imprinted snoRNAs were identified in the PWS homologous loci and the gene number was highly variable across lineages, with a peak in Euarchontoglires. Lineage-specific gene gain and loss events account for most extant genes of the HBII-52 (SNORD115) and the HBII-85 (SNORD116) gene family, and remarkable high gene-birth rates were observed in the primates and the rodents. Meanwhile, rapid sequence substitution occurred only in imprinted snoRNA genes, rather than their flanking sequences or the protein-coding genes located in the same imprinted locus. Strong selective constraints on the functional elements of these imprinted snoRNAs further suggest that they are subjected to birth-and-death evolution. Our data suggest that the regulatory role of HBII-52 on 5-HT2CR pre-mRNA might originate in the Euarchontoglires through adaptive process. We propose that the rapid evolution of PWS-related imprinted snoRNAs has contributed to the neural development of Euarchontoglires. PMID:24945811

Synthesis, characterization and evaluation of uniformly sized core-shell imprinted microspheres for the separation trans-resveratrol from giant knotweed

NASA Astrophysics Data System (ADS)

Zhang, Zhaohui; Liu, Li; Li, Hui; Yao, Shouzhuo

2009-09-01

A novel core-shell molecularly imprinting microspheres (MIMs) with trans-resveratrol as the template molecule; acrylamide (AA) as functional monomer and ethylene glycol dimethacrylate (EGDMA) as cross-linker, was prepared based on SiO 2 microspheres with surface imprinting technique. These core-shell trans-resveratrol imprinted microspheres were characterized by infrared spectra (IR), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), and high performance liquid chromatography (HPLC). The results showed that these core-shell imprinted microspheres, which take on perfect spherical shape with average shell thickness of 150 nm, exhibit especially selective recognition for trans-resveratrol. These imprinted microspheres were applied as solid-phase extraction materials for selective extraction of trans-resveratrol from giant knotweed extracting solution successfully.

Highly selective and efficient imprinted polymers based on carboxyl-functionalized magnetic nanoparticles for the extraction of gallic acid from pomegranate rind.

PubMed

Zhang, Junjie; Li, Benqiang; Yue, Huijuan; Wang, Jing; Zheng, Yuansuo

2018-01-01

With the combined surface imprinting technique and immobilized template strategy, molecularly imprinted magnetic nanoparticles were successfully prepared and coupled with high-performance liquid chromatography to selectively separate and determine gallic acid from the pomegranate rind. On the surface of carboxyl-functionalized magnetic nanospheres, thin imprinting shells were formed using dopamine as monomer and crosslinker. The characteristics, polymerization conditions, and adsorption performances of the resultant nanomaterials were investigated in detail. In addition of good crystallinity, satisfactory magnetism, and uniform morphology of the obtained polymers, they had rapid binding kinetics, high adsorption capacity, and favorable reusability. In the mixed solution of four hydroxybenzoic acids, the prepared nanomaterials have an excellent selectivity to gallic acid with an imprinting factor of as high as 17.5. Therefore, the polymers have great potentials in specific extraction and enrichment of gallic acid from the complex natural resources. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

The sorption properties of polymers with molecular imprints of chlorine-containing pesticides

NASA Astrophysics Data System (ADS)

Popov, S. A.; Dmitrienko, S. G.; Chumichkina, Yu. A.; Zolotov, Yu. A.

2009-04-01

Polymers with molecular imprints of 2,4-dichlorophenoxyacetic acid (2,4-D), 3,6-dichloro-2-methoxybenzoic acid (dicamba), and (RS)-1- p-chlorophenyl-4,4-dimethyl-3-(1H-1,2,4-triazol-1-ylmethyl) pentan-3-ol and the corresponding blank polymers were synthesized using acrylamide as a functional monomer. The specific surface area of the resulting materials was estimated and their sorption properties were studied. It was found that the sorption characteristics of the polymers with molecular imprints of chlorine-containing pesticides depended on the nature of template molecules, functional monomer: template ratio in the polymerization mixture, and nature and content of solvents varied at the synthesis stage. According to the sorption isotherms, the difference in the sorption behavior of molecularly imprinted and blank polymers was observed over a wide range of chlorine-containing pesticide concentrations. The selectivity of the adsorbent with 2,4-D imprints was estimated for the example of structurally related compounds.

Development of carbon dots modified fluorescent molecular imprinted Polymer@Ag/AgCl nanoparticle for hepatocellular carcinoma marker

NASA Astrophysics Data System (ADS)

Karfa, Paramita; Madhuri, Rashmi; Sharma, Prashant K.

2017-05-01

In this work, a sensitive and selective fluorescent molecularly imprinted polymer (MIP) was developed for detection of hepatocellular carcinoma (HCC) biomarker i.e. alpha feto protein (AFP) using Ag/AgCl as platform. Here, the carbon dots and Ag/AgCl nanoparticles were functionalized with vinyl groups and used as functional monomer for synthesis of AFP-imprinted polymer. The imprinted polymer shows a linear range of 3.96 ng mL-1 to 80.0 ng mL-1 with detection limit of 0.42 ng mL-1.The adsorption property of the MIP@Ag/AgCl was studied and shows the high affinity binding towards their target analyte without any cross-reactivity and false-positive or false-negative results.

An ion-imprinted silica-supported organic-inorganic hybrid sorbent prepared by a surface imprinting technique combined with a polysaccharide incorporated sol-gel process for selective separation of cadmium(II) from aqueous solution.

PubMed

Li, Feng; Jiang, Hongquan; Zhang, Shusheng

2007-03-15

Ion-imprinting concept and polysaccharide incorporated sol-gel process were applied to the preparation of a new silica-supported organic-inorganic hybrid sorbent for selective separation of Cd(II) from aqueous solution. In the prepared shell/core composite sorbent, covalently surface coating on the supporting silica gel was achieved by using a Cd(II)-imprinting sol-gel process starting from an inorganic precursor, gamma-glycidoxypropyltrimethoxysiloxane (GPTMS), and a functional biopolymer, chitosan (CS). The sorbent was prepared through self-hydrolysis of GPTMS, self-condensation and co-condensation of silanol groups (Si-OH) from siloxane and silica gel surface, in combination with in situ covalent cross-linking of CS with partial amine shielded by Cd(II) complexation. Extraction of the imprinting molecules left a predetermined arrangement of ligands and tailored binding pockets for Cd(II). The prepared sorbent was characterized by using X-ray energy dispersion spectroscopy (EDX), X-ray diffraction (XRD), and scanning electron microscopy (SEM). Batch experiments were conducted to study the sorption performance by removal of Cd(II) when present singly or in binary system, an aqueous Cd(II) and Zn(II) mixture. The ion-imprinted composite sorbent offered a fast kinetics for the sorption of Cd(II) and the maximum capacity was 1.14mmolg(-1). The uptake capacity of the imprinted sorbent and the selectivity coefficient were much higher than that of the non-imprinted sorbent. The imprinted sorbent exhibited high reusability. The prepared functional sorbent was shown to be promising for the preconcentration of cadmium in environmental and biological samples.

Mammalian-specific genomic functions: Newly acquired traits generated by genomic imprinting and LTR retrotransposon-derived genes in mammals.

PubMed

Kaneko-Ishino, Tomoko; Ishino, Fumitoshi

2015-01-01

Mammals, including human beings, have evolved a unique viviparous reproductive system and a highly developed central nervous system. How did these unique characteristics emerge in mammalian evolution, and what kinds of changes did occur in the mammalian genomes as evolution proceeded? A key conceptual term in approaching these issues is "mammalian-specific genomic functions", a concept covering both mammalian-specific epigenetics and genetics. Genomic imprinting and LTR retrotransposon-derived genes are reviewed as the representative, mammalian-specific genomic functions that are essential not only for the current mammalian developmental system, but also mammalian evolution itself. First, the essential roles of genomic imprinting in mammalian development, especially related to viviparous reproduction via placental function, as well as the emergence of genomic imprinting in mammalian evolution, are discussed. Second, we introduce the novel concept of "mammalian-specific traits generated by mammalian-specific genes from LTR retrotransposons", based on the finding that LTR retrotransposons served as a critical driving force in the mammalian evolution via generating mammalian-specific genes.

Selective enrichment and separation of phosphotyrosine peptides by thermosensitive molecularly imprinted polymers.

PubMed

Yang, Xiaoqing; Xia, Yan

2016-01-01

Novel thermosensitive molecularly imprinted polymers were successfully prepared using the epitope imprinting approach in the presence of the mimic template phenylphosphonic acid, the functional monomer vinylphosphonic acid-Ti(4+) , the temperature-sensitive monomer N-isopropylacrylamide and the crosslinker N,N'-methylenebisacrylamide. The ratio of the template/thermosensitive monomers/crosslinker was optimized, and when the ratio was 2:2:1, the prepared thermosensitive molecularly imprinted polymers had the highest imprinting factor. The synthetic thermosensitive molecularly imprinted polymers were characterized by Fourier transform infrared spectroscopy to reveal the combination and elution processes of the template. Then, the adsorption capacity and thermosensitivity was measured. When the temperature was 28°C, the imprinting factor was the highest. The selectivity and adsorption capacity of the thermosensitive molecularly imprinted polymers for phosphotyrosine peptides from a mixture of three tailor-made peptides were measured by high-performance liquid chromatography. The results showed that the thermosensitive molecularly imprinted polymers have good selectivity for phosphotyrosine peptides. Finally, the imprinted hydrogels were applied to specifically adsorb phosphotyrosine peptides from a sample mixture containing phosphotyrosine and a tryptic digest of β-casein, which demonstrated high selectivity. After four rebinding cycles, 78.9% adsorption efficiency was still retained. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Mechanism of molecular recognition on molecular imprinted monolith by capillary electrochromatography.

PubMed

Liu, Zhao-Sheng; Xu, Yan-Li; Yan, Chao; Gao, Ru-Yu

2005-09-16

The recognition mechanism of molecularly imprinted polymer (MIP) in capillary electrochromatography (CEC) is complicated since it possesses a hybrid process, which comprises the features of chromatographic retention, electrophoretic migration and molecular imprinting. For an understanding of the molecular recognition of MIP in CEC, a monolithic MIP in a capillary with 1,1'-binaphthyl-2,2'-diamine (BNA) imprinting was prepared by in situ copolymerization of imprinted molecule, methacrylic acid and ethylene glycol dimethacrylate in porogenic solvent, a mixture of toluene-isooctane. Strong recognition ability and high column performance (theory plates was 43,000 plates/m) of BNA were achieved on this monolithic MIP in CEC mode. In addition, BNA and its structural analogue, 1,1'-bi-2, 2'-naphthol, differing in functional groups, were used as model compounds to study imprinting effect on the resultant BNA-imprinted monolithic column, a reference column without imprinting of BNA and a open capillary. The effects of organic modifier concentration, pH value of buffer, salt concentration of buffer and column temperature on the retention and recognition of two compounds were investigated. The results showed that the molecular recognition on MIP monolith in CEC mode mainly derived from imprinting cavities on BNA-imprinted polymer other than chromatographic retention and electrophoretic migration.

On the influence of crosslinker on template complexation in molecularly imprinted polymers: a computational study of prepolymerization mixture events with correlations to template-polymer recognition behavior and NMR spectroscopic studies.

PubMed

Shoravi, Siamak; Olsson, Gustaf D; Karlsson, Björn C G; Nicholls, Ian A

2014-06-12

Aspects of the molecular-level basis for the function of ethylene glycol dimethacrylate and trimethylolproprane trimethacrylate crosslinked methacrylic acid copolymers molecularly imprinted with (S)-propranolol have been studied using a series of all-component and all-atom molecular dynamics studies of the corresponding prepolymerization systems. The crosslinking agents were observed to contribute to template complexation, and the results were contrasted with previously reported template-recognition behavior of the corresponding polymers. Differences in the extent to which the two crosslinkers interacted with the functional monomer were identified, and correlations were made to polymer-ligand recognition behavior and the results of nuclear magnetic resonance spectroscopic studies studies. This study demonstrates the importance of considering the functional monomer-crosslinker interaction when designing molecularly imprinted polymers, and highlights the often neglected general contribution of crosslinker to determining the nature of molecularly imprinted polymer-template selectivity.

Molecularly imprinted polymers for separation of various sugars from human urine.

PubMed

Okutucu, Burcu; Onal, Seçil

2011-12-15

Molecularly imprinted polymers were the new, simple and unexpensive materials that can be used in several clinical applications. Phenylboronic acid has been frequently used as functional monomer for the covalent imprinting of diols. In this study, the phenylboronic acid esters of fructose, galactose, glucose and raffinose were synthesized and then used as template analytes. The adsorption capacities of fructose, galactose and glucose-phenylboronic acid imprinted polymers were 75, 10 and 30%, respectively. The batch rebinding studies and Scatchard analysis were done for all sugar imprinted polymer. Glucose is one of the mostly found sugar in the urine. The glucose:phenylboronic acid imprinted polymer was used for the analysis of glucose, fructose, galactose, sucrose, maltose, lactose and raffinose in spiked urine. The selectivity of glucose:phenylboronic acid imprinted polymer to urine monosaccharides was found as nearly 45-55% and to di- and polysaccharides was found as 30-35%, respectively. Copyright © 2011 Elsevier B.V. All rights reserved.

A surface acoustic wave sensor functionalized with a polypyrrole molecularly imprinted polymer for selective dopamine detection.

PubMed

Maouche, Naima; Ktari, Nadia; Bakas, Idriss; Fourati, Najla; Zerrouki, Chouki; Seydou, Mahamadou; Maurel, François; Chehimi, Mohammed Mehdi

2015-11-01

A surface acoustic wave sensor operating at 104 MHz and functionalized with a polypyrrole molecularly imprinted polymer has been designed for selective detection of dopamine (DA). Optimization of pyrrole/DA ratio, polymerization and immersion times permitted to obtain a highly selective sensor, which has a sensitivity of 0.55°/mM (≈ 550 Hz/mM) and a detection limit of ≈ 10 nM. Morphology and related roughness parameters of molecularly imprinted polymer surfaces, before and after extraction of DA, as well as that of the non imprinted polymer were characterized by atomic force microscopy. The developed chemosensor selectively recognized dopamine over the structurally similar compound 4-hydroxyphenethylamine (referred as tyramine), or ascorbic acid,which co-exists with DA in body fluids at a much higher concentration. Selectivity tests were also carried out with dihydroxybenzene, for which an unexpected phase variation of order of 75% of the DA one was observed. Quantum chemical calculations, based on the density functional theory, were carried out to determine the nature of interactions between each analyte and the PPy matrix and the DA imprinted PPy polypyrrole sensing layer in order to account for the important phase variation observed during dihydroxybenzene injection. Copyright © 2015 John Wiley & Sons, Ltd.

Quantitative and functional interrogation of parent-of-origin allelic expression biases in the brain

PubMed Central

Perez, Julio D; Rubinstein, Nimrod D; Fernandez, Daniel E; Santoro, Stephen W; Needleman, Leigh A; Ho-Shing, Olivia; Choi, John J; Zirlinger, Mariela; Chen, Shau-Kwaun; Liu, Jun S; Dulac, Catherine

2015-01-01

The maternal and paternal genomes play different roles in mammalian brains as a result of genomic imprinting, an epigenetic regulation leading to differential expression of the parental alleles of some genes. Here we investigate genomic imprinting in the cerebellum using a newly developed Bayesian statistical model that provides unprecedented transcript-level resolution. We uncover 160 imprinted transcripts, including 41 novel and independently validated imprinted genes. Strikingly, many genes exhibit parentally biased—rather than monoallelic—expression, with different magnitudes according to age, organ, and brain region. Developmental changes in parental bias and overall gene expression are strongly correlated, suggesting combined roles in regulating gene dosage. Finally, brain-specific deletion of the paternal, but not maternal, allele of the paternally-biased Bcl-x, (Bcl2l1) results in loss of specific neuron types, supporting the functional significance of parental biases. These findings reveal the remarkable complexity of genomic imprinting, with important implications for understanding the normal and diseased brain. DOI: http://dx.doi.org/10.7554/eLife.07860.001 PMID:26140685

Molecularly imprinted electrochemical biosensor based on Fe@Au nanoparticles involved in 2-aminoethanethiol functionalized multi-walled carbon nanotubes for sensitive determination of cefexime in human plasma.

PubMed

Yola, Mehmet Lütfi; Eren, Tanju; Atar, Necip

2014-10-15

The molecular imprinting technique depends on the molecular recognition. It is a polymerization method around the target molecule. Hence, this technique creates specific cavities in the cross-linked polymeric matrices. In present study, a sensitive imprinted electrochemical biosensor based on Fe@Au nanoparticles (Fe@AuNPs) involved in 2-aminoethanethiol (2-AET) functionalized multi-walled carbon nanotubes (f-MWCNs) modified glassy carbon (GC) electrode was developed for determination of cefexime (CEF). The results of X-ray photoelectron spectroscopy (XPS) and reflection-absorption infrared spectroscopy (RAIRS) confirmed the formation of the developed surfaces. CEF imprinted film was constructed by cyclic voltammetry (CV) for 9 cycles in the presence of 80 mM pyrrole in phosphate buffer solution (pH 6.0) containing 20mM CEF. The developed electrochemical biosensor was validated according to the International Conference on Harmonisation (ICH) guideline and found to be linear, sensitive, selective, precise and accurate. The linearity range and the detection limit were obtained as 1.0 × 10(-10)-1.0 × 10(-8)M and 2.2 × 10(-11)M, respectively. The developed CEF imprinted sensor was successfully applied to real samples such as human plasma. In addition, the stability and reproducibility of the prepared molecular imprinted electrode were investigated. The excellent long-term stability and reproducibility of the prepared CEF imprinted electrodes make them attractive in electrochemical sensors. Copyright © 2014 Elsevier B.V. All rights reserved.

Formation of protein molecular imprints within Langmuir monolayers: A quartz crystal microbalance study

PubMed Central

Turner, Nicholas W.; Wright, Bryon E.; Hlady, Vladimir; Britt, David W.

2008-01-01

Protein imprinting leading to enhanced rebinding of ferritin to ternary lipid monolayers is demonstrated using a quartz crystal microbalance. Monolayers consisting of cationic dioctadecyldimethylammonium bromide, non-ionic methyl stearate, and poly(ethylene glycol) bearing phospholipids were imprinted with ferritin at the air/water interface of a Langmuir-Blodgett trough and transferred hydrated to hydrophobic substrates for study. This immobilization was shown by fluorescence correlation spectroscopy to significantly hinder any further diffusion of lipids, while rebinding studies demonstrated up to a six-fold increase in ferritin adsorption to imprinted versus control monolayers. A diminished rebinding of ferritin to its imprint was observed through pH reduction to below the protein isoelectric point, demonstrating the electrostatic nature of the interaction. Rebinding to films where imprint pockets remained occupied by the template protein was also minimal. Studies with a smaller acidic protein revealed the importance of the steric influence of poly(ethylene glycol) in forming the protein binding pockets, as albumin-imprinted monolayers showed low binding of ferritin, while ferritin-imprinted monolayers readily accommodated albumin. The controllable structure-function relationship and limitations of this system are discussed with respect to the application of protein imprinting in sensor development as well as fundamental studies of proteins at dynamic interfaces. PMID:17204279

Imprinting modulates processing of visual information in the visual wulst of chicks.

PubMed

Maekawa, Fumihiko; Komine, Okiru; Sato, Katsushige; Kanamatsu, Tomoyuki; Uchimura, Motoaki; Tanaka, Kohichi; Ohki-Hamazaki, Hiroko

2006-11-14

Imprinting behavior is one form of learning and memory in precocial birds. With the aim of elucidating of the neural basis for visual imprinting, we focused on visual information processing. A lesion in the visual wulst, which is similar functionally to the mammalian visual cortex, caused anterograde amnesia in visual imprinting behavior. Since the color of an object was one of the important cues for imprinting, we investigated color information processing in the visual wulst. Intrinsic optical signals from the visual wulst were detected in the early posthatch period and the peak regions of responses to red, green, and blue were spatially organized from the caudal to the nasal regions in dark-reared chicks. This spatial representation of color recognition showed plastic changes, and the response pattern along the antero-posterior axis of the visual wulst altered according to the color the chick was imprinted to. These results indicate that the thalamofugal pathway is critical for learning the imprinting stimulus and that the visual wulst shows learning-related plasticity and may relay processed visual information to indicate the color of the imprint stimulus to the memory storage region, e.g., the intermediate medial mesopallium.

Imprinting modulates processing of visual information in the visual wulst of chicks

PubMed Central

Maekawa, Fumihiko; Komine, Okiru; Sato, Katsushige; Kanamatsu, Tomoyuki; Uchimura, Motoaki; Tanaka, Kohichi; Ohki-Hamazaki, Hiroko

2006-01-01

Background Imprinting behavior is one form of learning and memory in precocial birds. With the aim of elucidating of the neural basis for visual imprinting, we focused on visual information processing. Results A lesion in the visual wulst, which is similar functionally to the mammalian visual cortex, caused anterograde amnesia in visual imprinting behavior. Since the color of an object was one of the important cues for imprinting, we investigated color information processing in the visual wulst. Intrinsic optical signals from the visual wulst were detected in the early posthatch period and the peak regions of responses to red, green, and blue were spatially organized from the caudal to the nasal regions in dark-reared chicks. This spatial representation of color recognition showed plastic changes, and the response pattern along the antero-posterior axis of the visual wulst altered according to the color the chick was imprinted to. Conclusion These results indicate that the thalamofugal pathway is critical for learning the imprinting stimulus and that the visual wulst shows learning-related plasticity and may relay processed visual information to indicate the color of the imprint stimulus to the memory storage region, e.g., the intermediate medial mesopallium. PMID:17101060

Acetic and Acrylic Acid Molecular Imprinted Model Silicone Hydrogel Materials for Ciprofloxacin-HCl Delivery

PubMed Central

Hui, Alex; Sheardown, Heather; Jones, Lyndon

2012-01-01

Contact lenses, as an alternative drug delivery vehicle for the eye compared to eye drops, are desirable due to potential advantages in dosing regimen, bioavailability and patient tolerance/compliance. The challenge has been to engineer and develop these materials to sustain drug delivery to the eye for a long period of time. In this study, model silicone hydrogel materials were created using a molecular imprinting strategy to deliver the antibiotic ciprofloxacin. Acetic and acrylic acid were used as the functional monomers, to interact with the ciprofloxacin template to efficiently create recognition cavities within the final polymerized material. Synthesized materials were loaded with 9.06 mM, 0.10 mM and 0.025 mM solutions of ciprofloxacin, and the release of ciprofloxacin into an artificial tear solution was monitored over time. The materials were shown to release for periods varying from 3 to 14 days, dependent on the loading solution, functional monomer concentration and functional monomer:template ratio, with materials with greater monomer:template ratio (8:1 and 16:1 imprinted) tending to release for longer periods of time. Materials with a lower monomer:template ratio (4:1 imprinted) tended to release comparatively greater amounts of ciprofloxacin into solution, but the release was somewhat shorter. The total amount of drug released from the imprinted materials was sufficient to reach levels relevant to inhibit the growth of common ocular isolates of bacteria. This work is one of the first to demonstrate the feasibility of molecular imprinting in model silicone hydrogel-type materials. PMID:28817033

Molecularly Imprinted Polymers and Highly Porous Materials in Sensing Applications

DTIC Science & Technology

2007-04-01

electrochemical in form. Piletsky and Turner (69) indicate that there are three critical issues to the design of MIP based sensors. These are the...imprinting procedures”, Anal. Bioanal. Chem., 377, 540-549 (2003). 26. O. Y. F. Henry, D. C. Cullen and S. A. Piletsky , “Optical interrogation of...Rouillon, E. V. Piletska, A. Guerreiro, I. Chianella and S. A. Piletsky , “How to find effective functional monomers for effective molecularly imprinted

Novel approach for extraction of quercetin using molecular imprinted membranes

NASA Astrophysics Data System (ADS)

Kamarudin, Siti Fatimah; Ahmad, Mohd Noor; Dzahir, Irfan Hatim Mohamed; Nasir, Azalina Mohamed; Ishak, Noorhidayah; Halim, Nurul Farhanah

2017-12-01

Quercetin imprinted membrane (QIM) was synthesized and applied for the extraction of quercetin. The quercetin imprinted membranes (QIM) were fabricated through a non-covalent approach via surface thermal polymerization. Polyvinylidene fluoride (PVDF) microfiltration membrane was used as a support to improve mechanical stability of the membrane. The thin imprinted layer was formed by copolymerization of acrylamide (AA) as functional monomer and ethylene glycol dimethacrylate (EGDMA) as crosslinker in the presence of quercetin as template in tetrahydrofuran (THF) solution. The Atomic Force Microscopy (AFM) and Field Emission Scanning Electron Microscope (FESEM) were used to visualize the surface of membrane. Batch rebinding and binding kinetic experiments proved that the binding properties of the QIM are higher than non-imprinted membranes (NIM). QIM also have higher selectivity towards quercetin compared to sinensetin and rosmarinic acid.

Exercise-associated DNA methylation change in skeletal muscle and the importance of imprinted genes: a bioinformatics meta-analysis.

PubMed

Brown, William M

2015-12-01

Epigenetics is the study of processes--beyond DNA sequence alteration--producing heritable characteristics. For example, DNA methylation modifies gene expression without altering the nucleotide sequence. A well-studied DNA methylation-based phenomenon is genomic imprinting (ie, genotype-independent parent-of-origin effects). We aimed to elucidate: (1) the effect of exercise on DNA methylation and (2) the role of imprinted genes in skeletal muscle gene networks (ie, gene group functional profiling analyses). Gene ontology (ie, gene product elucidation)/meta-analysis. 26 skeletal muscle and 86 imprinted genes were subjected to g:Profiler ontology analysis. Meta-analysis assessed exercise-associated DNA methylation change. g:Profiler found four muscle gene networks with imprinted loci. Meta-analysis identified 16 articles (387 genes/1580 individuals) associated with exercise. Age, method, sample size, sex and tissue variation could elevate effect size bias. Only skeletal muscle gene networks including imprinted genes were reported. Exercise-associated effect sizes were calculated by gene. Age, method, sample size, sex and tissue variation were moderators. Six imprinted loci (RB1, MEG3, UBE3A, PLAGL1, SGCE, INS) were important for muscle gene networks, while meta-analysis uncovered five exercise-associated imprinted loci (KCNQ1, MEG3, GRB10, L3MBTL1, PLAGL1). DNA methylation decreased with exercise (60% of loci). Exercise-associated DNA methylation change was stronger among older people (ie, age accounted for 30% of the variation). Among older people, genes exhibiting DNA methylation decreases were part of a microRNA-regulated gene network functioning to suppress cancer. Imprinted genes were identified in skeletal muscle gene networks and exercise-associated DNA methylation change. Exercise-associated DNA methylation modification could rewind the 'epigenetic clock' as we age. CRD42014009800. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

Mammalian-specific genomic functions: Newly acquired traits generated by genomic imprinting and LTR retrotransposon-derived genes in mammals

PubMed Central

KANEKO-ISHINO, Tomoko; ISHINO, Fumitoshi

2015-01-01

Mammals, including human beings, have evolved a unique viviparous reproductive system and a highly developed central nervous system. How did these unique characteristics emerge in mammalian evolution, and what kinds of changes did occur in the mammalian genomes as evolution proceeded? A key conceptual term in approaching these issues is “mammalian-specific genomic functions”, a concept covering both mammalian-specific epigenetics and genetics. Genomic imprinting and LTR retrotransposon-derived genes are reviewed as the representative, mammalian-specific genomic functions that are essential not only for the current mammalian developmental system, but also mammalian evolution itself. First, the essential roles of genomic imprinting in mammalian development, especially related to viviparous reproduction via placental function, as well as the emergence of genomic imprinting in mammalian evolution, are discussed. Second, we introduce the novel concept of “mammalian-specific traits generated by mammalian-specific genes from LTR retrotransposons”, based on the finding that LTR retrotransposons served as a critical driving force in the mammalian evolution via generating mammalian-specific genes. PMID:26666304

Molecularly Imprinted Polymers: Present and Future Prospective

PubMed Central

Vasapollo, Giuseppe; Sole, Roberta Del; Mergola, Lucia; Lazzoi, Maria Rosaria; Scardino, Anna; Scorrano, Sonia; Mele, Giuseppe

2011-01-01

Molecular Imprinting Technology (MIT) is a technique to design artificial receptors with a predetermined selectivity and specificity for a given analyte, which can be used as ideal materials in various application fields. Molecularly Imprinted Polymers (MIPs), the polymeric matrices obtained using the imprinting technology, are robust molecular recognition elements able to mimic natural recognition entities, such as antibodies and biological receptors, useful to separate and analyze complicated samples such as biological fluids and environmental samples. The scope of this review is to provide a general overview on MIPs field discussing first general aspects in MIP preparation and then dealing with various application aspects. This review aims to outline the molecularly imprinted process and present a summary of principal application fields of molecularly imprinted polymers, focusing on chemical sensing, separation science, drug delivery and catalysis. Some significant aspects about preparation and application of the molecular imprinting polymers with examples taken from the recent literature will be discussed. Theoretical and experimental parameters for MIPs design in terms of the interaction between template and polymer functionalities will be considered and synthesis methods for the improvement of MIP recognition properties will also be presented. PMID:22016636

Identification of the human homolog of the imprinted mouse Air non-coding RNA

PubMed Central

Yotova, Iveta Y.; Vlatkovic, Irena M.; Pauler, Florian M.; Warczok, Katarzyna E.; Ambros, Peter F.; Oshimura, Mitsuo; Theussl, Hans-Christian; Gessler, Manfred; Wagner, Erwin F.; Barlow, Denise P.

2010-01-01

Genomic imprinting is widely conserved amongst placental mammals. Imprinted expression of IGF2R, however, differs between mice and humans. In mice, Igf2r imprinted expression is seen in all fetal and adult tissues. In humans, adult tissues lack IGF2R imprinted expression, but it is found in fetal tissues and Wilms' tumors where it is polymorphic and only seen in a small proportion of tested samples. Mouse Igf2r imprinted expression is controlled by the Air (Airn) ncRNA whose promoter lies in an intronic maternally-methylated CpG island. The human IGF2R gene carries a homologous intronic maternally-methylated CpG island of unknown function. Here, we use transfection and transgenic studies to show that the human IGF2R intronic CpG island is a ncRNA promoter. We also identify the same ncRNA at the endogenous human locus in 16–40% of Wilms' tumors. Thus, the human IGF2R gene shows evolutionary conservation of key features that control imprinted expression in the mouse. PMID:18789384

Trends in imprint lithography for biological applications.

PubMed

Truskett, Van N; Watts, Michael P C

2006-07-01

Imprint lithography is emerging as an alternative nano-patterning technology to traditional photolithography that permits the fabrication of 2D and 3D structures with <100 nm resolution, patterning and modification of functional materials other than photoresist and is low cost, with operational ease for use in developing bio-devices. Techniques for imprint lithography, categorized as either 'molding and embossing' or 'transfer printing', will be discussed in the context of microarrays for genomics, proteomics and tissue engineering. Specifically, fabrication by nanoimprint lithography (NIL), UV-NIL, step and flash imprint lithography (S-FIL), micromolding by elastomeric stamps and micro- and nano-contact printing will be reviewed.

Separation and purification of thymopentin with molecular imprinting membrane by solid phase extraction disks.

PubMed

Wang, Chaoli; Hu, Xiaoling; Guan, Ping; Wu, Danfeng; Qian, Liwei; Li, Ji; Song, Renyuan

2015-01-01

The synthesis and performance of molecularly imprinted membranes (MIMs) as a solid phase extraction packing materials for the separation and purification of thymopentin from crude samples was described. In order to increase structural selectivity and imprinting efficiency, surface-initiated ATRP and ionic liquid (1-vinyl-3-ethyl acetate imidazolium chloride) were used to prepare molecularly imprinting membranes. The results demonstrated that solid phase extraction disks stuffed by MIMs with ionic liquids as functional monomer demonstrated high isolation and purification of performance to the thymopentin. The molecular recognition of thymopentin was analyzed by using molecular modeling software. Copyright © 2014 Elsevier B.V. All rights reserved.

Natural breaking of the maternal silence at the mouse and human imprinted Prader-Willi locus: A whisper with functional consequences.

PubMed

Matarazzo, Valery; Muscatelli, Françoise

2013-01-01

Genomic imprinting is a normal process of epigenetic regulation leading some autosomal genes to be expressed from one parental allele only, the other parental allele being silenced. The reasons why this mechanism has been selected throughout evolution are not clear; however, expression dosage is critical for imprinted genes. There is a paradox between the fact that genomic imprinting is a robust mechanism controlling the expression of specific genes and the fact that this mechanism is based on epigenetic regulation that, per se, should present some flexibility. The robustness has been well studied, revealing the epigenetic modifications at the imprinted locus, but the flexibility has been poorly investigated.   Prader-Willi syndrome is the best-studied disease involving imprinted genes caused by the absence of expression of paternally inherited alleles of genes located in the human 15q11-q13 region. Until now, the silencing of the maternally inherited alleles was like a dogma. Rieusset et al. showed that in absence of the paternal Ndn allele, in Ndn +m/-p mice, the maternal Ndn allele is expressed at an extremely low level with a high degree of non-genetic heterogeneity. In about 50% of these mutant mice, this stochastic expression reduces birth lethality and severity of the breathing deficiency, correlated with a reduction in the loss of serotonergic neurons. Furthermore, using several mouse models, they reveal a competition between non-imprinted Ndn promoters, which results in monoallelic (paternal or maternal) Ndn expression, suggesting that Ndn monoallelic expression occurs in the absence of imprinting regulation. Importantly, specific expression of the maternal NDN allele is also detected in post-mortem brain samples of PWS individuals. Here, similar expression of the Magel2 maternal allele is reported in Magel2 +m/-p mice, suggesting that this loss of imprinting can be extended to other PWS genes. These data reveal an unexpected epigenetic flexibility of PWS imprinted genes that could be exploited to reactivate the functional but dormant maternal alleles in PWS.

Pervasive polymorphic imprinted methylation in the human placenta

PubMed Central

Hanna, Courtney W.; Peñaherrera, Maria S.; Saadeh, Heba; Andrews, Simon; McFadden, Deborah E.; Kelsey, Gavin; Robinson, Wendy P.

2016-01-01

The maternal and paternal copies of the genome are both required for mammalian development, and this is primarily due to imprinted genes, those that are monoallelically expressed based on parent-of-origin. Typically, this pattern of expression is regulated by differentially methylated regions (DMRs) that are established in the germline and maintained after fertilization. There are a large number of germline DMRs that have not yet been associated with imprinting, and their function in development is unknown. In this study, we developed a genome-wide approach to identify novel imprinted DMRs in the human placenta and investigated the dynamics of these imprinted DMRs during development in somatic and extraembryonic tissues. DNA methylation was evaluated using the Illumina HumanMethylation450 array in 134 human tissue samples, publicly available reduced representation bisulfite sequencing in the human embryo and germ cells, and targeted bisulfite sequencing in term placentas. Forty-three known and 101 novel imprinted DMRs were identified in the human placenta by comparing methylation between diandric and digynic triploid conceptions in addition to female and male gametes. Seventy-two novel DMRs showed a pattern consistent with placental-specific imprinting, and this monoallelic methylation was entirely maternal in origin. Strikingly, these DMRs exhibited polymorphic imprinted methylation between placental samples. These data suggest that imprinting in human development is far more extensive and dynamic than previously reported and that the placenta preferentially maintains maternal germline-derived DNA methylation. PMID:26769960

Chemosensory orientation behavior in juvenile sea turtles.

PubMed

Grassman, M

1993-01-01

It has been widely believed for several decades that hatchling sea turtles imprint to chemical cues characteristic of their natal beach and use this information as part of a repertoire of mechanisms enabling their return to the same beach for mating and nesting. This has proven very difficult to test. Although the imprinting theory is conceptually simple, functionally it is quite complex. This involves not only chemical imprinting of nestlings but growth and migration to habitats where the adults are found, long-term memory of their earlier chemical exposure, reproductive maturation, and homing. A few studies have been conducted to examine these elements of the imprinting theory. Experiments involving the exposure of embryos and hatchlings to chemicals suggest that juvenile turtles 'imprint' to the chemical environment of their nest. This can be termed chemical imprinting. Loggerhead turtles, Caretta caretta, and ridley turtles, Lepidochelys kempi, appear to be attracted to chemicals (morpholine and natural seawater, respectively) to which they were exposed as embryos. The strongest support for chemical imprinting is that six-month-old green turtles, Chelonia mydas, exposed to either morpholine or 2-phenylethanol in the nest and for a period of time after hatching, respond similarly to the chemical to which they were exposed as nestlings. Although chemical imprinting does not 'prove' the imprinting theory of turtle homing, it is a necessary component of the theory not previously examined.

Molecularly imprinted electrochemical sensor based on amine group modified graphene covalently linked electrode for 4-nonylphenol detection.

PubMed

Chen, Hong-Jun; Zhang, Zhao-Hui; Cai, Rong; Chen, Xing; Liu, Yu-Nan; Rao, Wei; Yao, Shou-Zhuo

2013-10-15

In this work, an imprinted electrochemical sensor based on electrochemical reduced graphene covalently modified carbon electrode was developed for the determination of 4-nonylphenol (NP). An amine-terminated functional graphene oxide was covalently modified onto the electrode surface with diazonium salt reactions to improve the stability and reproducibility of the imprinted sensor. The electrochemical properties of each modified electrodes were investigated with differential pulse voltammetry (DPV). The electrochemical characteristic of the imprinted sensor was also investigated using electrochemical impedance spectroscopy (EIS) in detail. The response currents of the imprinted electrode exhibited a linear relationship toward 4-nonylphenol concentration ranging from 1.0 × 10(-11) to 1.0 × 10(-8) gm L(-1) with the detection limit of 3.5 × 10(-12) gm L(-1) (S/N=3). The fabricated electrochemical imprinted sensor was successfully applied to the detection of 4-nonylphenol in rain and lake water samples. Crown Copyright © 2013 Published by Elsevier B.V. All rights reserved.

Synthesis and application of ion-imprinted polymer nanoparticles for the extraction and preconcentration of mercury in water and food samples employing cold vapor atomic absorption spectrometry.

PubMed

Roushani, Mahmoud; Abbasi, Shahryar; Khani, Hossein

2015-09-01

We describe a nanosized Hg(II)-imprinted polymer that was prepared from methacrylic acid as functional monomer, ethyleneglycol dimethacrylate as cross-linker, 2,2'-azobisisobutyronitrile (AIBN) as radical initiator, 2, 2'-di pyrydyl amine as a specific ligand, and Hg (II) as the template ions by precipitation polymerization method in methanol as the progeny solvent. Batch adsorption experiments were carried out as a function of pH, Hg (II) imprinted polymer amount, adsorption and desorption time, volume, and concentration of eluent. The synthesized polymer particles were characterized physically and morphologically by using infrared spectroscopy, thermogravimetric analysis, X-ray diffraction, and scanning electron microscopic techniques. The maximum adsorption capacity of the ion-imprinted and non-imprinted sorbent was 27.96 and 7.89 mg g(-1), respectively. Under optimal conditions, the detection limit for mercury was 0.01 μg L(-1) and the relative standard deviation was 3.2 % (n = 6) at the 1.00 μg L(-1). The procedure was applied to determination of mercury in fish and water samples with satisfactory results.

Effective determination of a pharmaceutical, sulpiride, in river water by online SPE-LC-MS using a molecularly imprinted polymer as a preconcentration medium.

PubMed

Kubo, Takuya; Kuroda, Kenta; Tominaga, Yuichi; Naito, Toyohiro; Sueyoshi, Kenji; Hosoya, Ken; Otsuka, Koji

2014-02-01

We report an effective and a quantitative analysis method for one of pharmaceuticals, sulpiride, in river water by online solid phase extraction (SPE) connected with liquid chromatography-mass spectrometry (LC-MS) using a molecularly imprinted polymer as a preconcentration medium. The polymer prepared with a pseudo template molecule showed the selective retention ability based on the interval recognition of functional groups in sulpiride. Also, the imprinted polymer provided an effective concentration of a trace level of sulpiride in offline SPE with dual washing processes using water and acetonitrile, although another imprinted polymer prepared by an authentic method using sulpiride and methacrylic acid as a template and a functional monomer, respectively, showed the selective adsorption only in organic solvents. Furthermore, we employed the imprinted polymer as the preconcentration column of online SPE-LC-MS and the results supposed that the proposed system allowed the quantitative analysis of sulpiride with high sensitivity and recovery (10ng/L at 96%). Additionally, the determination of sulpiride in real river water without an additional spiking was effectively achieved by the system. Copyright © 2013 Elsevier B.V. All rights reserved.

Magnetorheological Finishing for Imprinting Continuous Phase Plate Structure onto Optical Surfaces

DOE Office of Scientific and Technical Information (OSTI.GOV)

Menapace, J A; Dixit, S N; Genin, F Y

2004-01-05

Magnetorheological finishing (MRF) techniques have been developed to manufacture continuous phase plates (CPP's) and custom phase corrective structures on polished fused silica surfaces. These phase structures are important for laser applications requiring precise manipulation and control of beam-shape, energy distribution, and wavefront profile. The MRF's unique deterministic-sub-aperture polishing characteristics make it possible to imprint complex topographical information onto optical surfaces at spatial scale-lengths approaching 1 mm. In this study, we present the results of experiments and model calculations that explore imprinting two-dimensional sinusoidal structures. Results show how the MRF removal function impacts and limits imprint fidelity and what must bemore » done to arrive at a high quality surface. We also present several examples of this imprinting technology for fabrication of phase correction plates and CPPs for use at high fluences.« less

Neural basis of imprinting behavior in chicks.

PubMed

Nakamori, Tomoharu; Maekawa, Fumihiko; Sato, Katsushige; Tanaka, Kohichi; Ohki-Hamazaki, Hiroko

2013-01-01

Newly hatched chicks memorize the characteristics of the first moving object they encounter, and subsequently show a preference for it. This "imprinting" behavior is an example of infant learning and is elicited by visual and/or auditory cues. Visual information of imprinting stimuli in chicks is first processed in the visual Wulst (VW), a telencephalic area corresponding to the mammalian visual cortex, congregates in the core region of the hyperpallium densocellulare (HDCo) cells, and transmitted to the intermediate medial mesopallium (IMM), a region similar to the mammalian association cortex. The imprinting memory is stored in the IMM, and activities of IMM neurons are altered by imprinting. Imprinting also induces functional and structural plastic changes of neurons in the circuit that links the VW and the IMM. Of these neurons, the activity of the HDCo cells is strongly influenced by imprinting. Expression and modulation of NR2B subunit-containing N-methyl-D-aspartate (NMDA) receptors in the HDCo cells are crucial for plastic changes in this circuit as well as the process of visual imprinting. Thus, elucidation of cellular and molecular mechanisms underlying the plastic changes that occurred in the HDCo cells may provide useful knowledge about infant learning. © 2012 The Authors Development, Growth & Differentiation © 2012 Japanese Society of Developmental Biologists.

Polydopamine-coated magnetic molecularly imprinted polymer for the selective solid-phase extraction of cinnamic acid, ferulic acid and caffeic acid from radix scrophulariae sample.

PubMed

Yin, Yuli; Yan, Liang; Zhang, Zhaohui; Wang, Jing; Luo, Ningjing

2016-04-01

We describe novel cinnamic acid polydopamine-coated magnetic imprinted polymers for the simultaneous selective extraction of cinnamic acid, ferulic acid and caffeic acid from radix scrophulariae sample. The novel magnetic imprinted polymers were synthesized by surface imprinting polymerization using magnetic multi-walled carbon nanotubes as the support material, cinnamic acid as the template and dopamine as the functional monomer. The magnetic imprinted polymers were characterized by transmission electron microscopy, scanning electron microscopy, Fourier transform infrared spectroscopy and vibrating sample magnetometry. The results revealed that the magnetic imprinted polymers had outstanding magnetic properties, high adsorption capacity, selectivity and fast kinetic binding toward cinnamic acid, ferulic acid and caffeic acid. Coupled with high-performance liquid chromatography, the extraction conditions of the magnetic imprinted polymers as a magnetic solid-phase extraction sorbent were investigated in detail. The proposed imprinted magnetic solid phase extraction procedure has been used for the purification and enrichment of cinnamic acid, ferulic acid and caffeic acid successfully from radix scrophulariae extraction sample with recoveries of 92.4-115.0% for cinnamic acid, 89.4-103.0% for ferulic acid and 86.6-96.0% for caffeic acid. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Preparation of molecularly imprinted polymers specific to glycoproteins, glycans and monosaccharides via boronate affinity controllable-oriented surface imprinting.

PubMed

Xing, Rongrong; Wang, Shuangshou; Bie, Zijun; He, Hui; Liu, Zhen

2017-05-01

Molecularly imprinted polymers (MIPs) are materials that are designed to be receptors for a template molecule (e.g., a protein). They are made by polymerizing the polymerizable reagents in the presence of the template; when the template is removed, the material can be used for many applications that would traditionally use antibodies. Thus, MIPs are biomimetic of antibodies and in this capacity have found wide applications, such as sensing, separation and diagnosis. However, many imprinting approaches are uncontrollable, and facile imprinting approaches widely applicable to a large variety of templates remain limited. We developed an approach called boronate affinity controllable-oriented surface imprinting, which allows for easy and efficient preparation of MIPs specific to glycoproteins, glycans and monosaccharides. This approach relies on immobilization of a template (glycoprotein, glycan or monosaccharide) on a boronic-acid-functionalized substrate through boronate affinity interaction, followed by self-polymerization of biocompatible monomer(s) to form an imprinting layer on the substrate with appropriate thickness. Imprinting in this approach is performed in a controllable manner, permitting the thickness of the imprinting layer to be fine-tuned according to the molecular size of the template by adjusting the imprinting time. This not only simplifies the imprinting procedure but also makes the approach widely applicable to a large range of sugar-containing biomolecules. MIPs prepared by this approach exhibit excellent binding properties and can be applied to complex real samples. The MIPs prepared by this protocol have been used in affinity separation, disease diagnosis and bioimaging. The entire protocol, including preparation, property characterization and performance evaluation, takes ∼3-8 d, depending on the type of substrate and template used.

Mesoporous structured MIPs@CDs fluorescence sensor for highly sensitive detection of TNT.

PubMed

Xu, Shoufang; Lu, Hongzhi

2016-11-15

A facile strategy was developed to prepare mesoporous structured molecularly imprinted polymers capped carbon dots (M-MIPs@CDs) fluorescence sensor for highly sensitive and selective determination of TNT. The strategy using amino-CDs directly as "functional monomer" for imprinting simplify the imprinting process and provide well recognition sites accessibility. The as-prepared M-MIPs@CDs sensor, using periodic mesoporous silica as imprinting matrix, and amino-CDs directly as "functional monomer", exhibited excellent selectivity and sensitivity toward TNT with detection limit of 17nM. The recycling process was sustainable for 10 times without obvious efficiency decrease. The feasibility of the developed method in real samples was successfully evaluated through the analysis of TNT in soil and water samples with satisfactory recoveries of 88.6-95.7%. The method proposed in this work was proved to be a convenient and practical way to prepare high sensitive and selective fluorescence MIPs@CDs sensors. Copyright © 2016 Elsevier B.V. All rights reserved.

Genomic imprinting, growth control and the allocation of nutritional resources: consequences for postnatal life.

PubMed

Charalambous, Marika; da Rocha, Simão Teixeira; Ferguson-Smith, Anne C

2007-02-01

Genes subject to genomic imprinting are predominantly expressed from one of the two parental chromosomes, are often clustered in the genome, and their activity and repression are epigenetically regulated. The role of imprinted genes in growth control has been apparent since the discovery of imprinting in the early 1980s. Drawing from studies in the mouse, we propose three distinct classes of imprinted genes - those expressed, imprinted and acting predominantly within the placenta, those with no associated foetal growth effects that act postnatally to regulate metabolic processes, and those expressed in the embryo and placenta that programme the development of organs participating in metabolic processes. Members of this latter class may interact in functional networks regulating the interaction between the mother and the foetus, affecting generalized foetal well-being, growth and organ development; they may also coordinately regulate the development of particular organ systems. The mono-allelic behaviour and sensitivity to changes in regional epigenetic states renders imprinted genes adaptable and vulnerable; in all cases, their perturbed dosage can compromise prenatal and/or postnatal control of nutritional resources. This finding has implications for understanding the relationships between prenatal events and diseases later in life.

Synthesis of molecularly imprinted dye-silica nanocomposites with high selectivity and sensitivity: Fluorescent imprinted sensor for rapid and efficient detection of τ-fluvalinate in vodka.

PubMed

Wang, Yunyun; Wang, Jixiang; Cheng, Rujia; Sun, Lin; Dai, Xiaohui; Yan, Yongsheng

2018-04-01

An imprinted fluorescent sensor was fabricated based on SiO 2 nanoparticles encapsulated with a molecularly imprinted polymer containing allyl fluorescein. High fluorine cypermethirin as template molecules, methyl methacrylate as functional monomer, and allyl fluorescein as optical materials synthesized a core-shell fluorescent molecular imprinted sensor, which showed a high and rapid sensitivity and selectivity for the detection of τ-fluvalinate. The sensor presented appreciable sensitivity with a limit of 13.251 nM, rapid detection that reached to equilibrium within 3 min, great linear relationship in the relevant concentration range from 0 to 150 nM, and excellent selectivity over structural analogues. In addition, the fluorescent sensor demonstrated desirable regeneration ability (eight cycling operations). The molecularly imprinted polymers ensured specificity, while the fluorescent dyes provided the stabile sensitivity. Finally, an effective application of the sensor was implemented by the detection of τ-fluvalinate in real samples from vodka. The molecularly imprinted fluorescent sensor showed a promising potential in environmental monitoring and food safety. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Student award for outstanding research winner in the Ph.D. category for the 2017 society for biomaterials annual meeting and exposition, april 5-8, 2017, Minneapolis, Minnesota: Characterization of protein interactions with molecularly imprinted hydrogels that possess engineered affinity for high isoelectric point biomarkers.

PubMed

Clegg, John R; Zhong, Justin X; Irani, Afshan S; Gu, Joann; Spencer, David S; Peppas, Nicholas A

2017-06-01

Molecularly imprinted polymers (MIPs) with selective affinity for protein biomarkers could find extensive utility as environmentally robust, cost-efficient biomaterials for diagnostic and therapeutic applications. In order to develop recognitive, synthetic biomaterials for prohibitively expensive protein biomarkers, we have developed a molecular imprinting technique that utilizes structurally similar, analogue proteins. Hydrogel microparticles synthesized by molecular imprinting with trypsin, lysozyme, and cytochrome c possessed an increased affinity for alternate high isoelectric point biomarkers both in isolation and plasma-mimicking adsorption conditions. Imprinted and non-imprinted P(MAA-co-AAm-co-DEAEMA) microgels containing PMAO-PEGMA functionalized polycaprolactone nanoparticles were net-anionic, polydisperse, and irregularly shaped. MIPs and control non-imprinted polymers (NIPs) exhibited regions of Freundlich and BET isotherm adsorption behavior in a range of non-competitive protein solutions, where MIPs exhibited enhanced adsorption capacity in the Freundlich isotherm regions. In a competitive condition, imprinting with analogue templates (trypsin, lysozyme) increased the adsorption capacity of microgels for cytochrome c by 162% and 219%, respectively, as compared to a 122% increase provided by traditional bulk imprinting with cytochrome c. Our results suggest that molecular imprinting with analogue protein templates is a viable synthetic strategy for enhancing hydrogel-biomarker affinity and promoting specific protein adsorption behavior in biological fluids. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 1565-1574, 2017. © 2017 Wiley Periodicals, Inc.

Epimutation profiling in Beckwith-Wiedemann syndrome: relationship with assisted reproductive technology

PubMed Central

2013-01-01

Background Beckwith-Wiedemann syndrome (BWS) is a congenital overgrowth disorder associated with abnormalities in 11p15.5 imprinted genes. The most common cause is loss of methylation (epimutation) at the imprinting control centre 2 (IC2/KvDMR1). Most IC2 epimutations occur sporadically but an association with conception after assisted reproductive technologies (ART) has been reported. A subgroup of IC2 epimutation cases also harbour epimutations at other imprinting centres (ICs) outside of 11p15.5. We have investigated the relationship between these multiple epimutation cases (ME+), history of ART and clinical phenotype in a cohort of 187 BWS IC2 epimutation patients. Results Methylation analysis at PLAGL1, MEST and IGF2R ICs demonstrated an over-representation of patients with abnormally low methylation (8.5%, 12% and 6% respectively). At IGF2R some patients (2%) had gain of methylation but this was also detected in controls. Though there were no significant correlations between the methylation index (MIs) at the three ICs tested, a subset of patients appeared to be susceptible to multiple epimutations (ME+) and 21.2% of ME + patients had been conceived by ART compared to 4.5% (P = 0.0033) without additional epimutations. Methylation array profiling (Illumina Goldengate®) of patients and controls (excluding 11p15.5 loci) demonstrated significant differences between patients and controls. No significant associations were found between aspects of the BWS phenotype and individual epimutations but we describe a case presenting with a post-ART BWS-like phenotype in which molecular analysis demonstrated loss of paternal allele methylation at the 11p15.5 IC1 locus (IC1 regulates imprinting of IGF2 and H19). Loss of paternal allele methylation at the IC1 is the molecular finding associated with Silver-Russell syndrome whereas BWS is associated with gain of maternal allele methylation at IC1. Further analysis demonstrated epimutations at PLAGL1 and MEST consistent with the hypothesis that the presence of multiple epimutations may be of clinical relevance. Conclusions These findings suggest that the ME + subgroup of BWS patients are preferentially, but not exclusively, associated with a history of ART and that, though at present, there are no clear epigenotype-phenotype correlations for ME + BWS patients, non-11p15.5 IC epimutations can influence clinical phenotype. PMID:24325814

A molecularly imprinted polymer (MIP)-coated microbeam MEMS sensor for chemical detection

NASA Astrophysics Data System (ADS)

Holthoff, Ellen L.; Li, Lily; Hiller, Tobias; Turner, Kimberly L.

2015-05-01

Recently, microcantilever-based technology has emerged as a viable sensing platform due to its many advantages such as small size, high sensitivity, and low cost. However, microcantilevers lack the inherent ability to selectively identify hazardous chemicals (e.g., explosives, chemical warfare agents). The key to overcoming this challenge is to functionalize the top surface of the microcantilever with a receptor material (e.g., a polymer coating) so that selective binding between the cantilever and analyte of interest takes place. Molecularly imprinted polymers (MIPs) can be utilized as artificial recognition elements for target chemical analytes of interest. Molecular imprinting involves arranging polymerizable functional monomers around a template molecule followed by polymerization and template removal. The selectivity for the target analyte is based on the spatial orientation of the binding site and covalent or noncovalent interactions between the functional monomer and the analyte. In this work, thin films of sol-gel-derived xerogels molecularly imprinted for TNT and dimethyl methylphosphonate (DMMP), a chemical warfare agent stimulant, have demonstrated selectivity and stability in combination with a fixed-fixed beam microelectromechanical systems (MEMS)-based gas sensor. The sensor was characterized by parametric bifurcation noise-based tracking.

[Evolution of genomic imprinting in mammals: what a zoo!].

PubMed

Proudhon, Charlotte; Bourc'his, Déborah

2010-05-01

Genomic imprinting imposes an obligate mode of biparental reproduction in mammals. This phenomenon results from the monoparental expression of a subset of genes. This specific gene regulation mechanism affects viviparous mammals, especially eutherians, but also marsupials to a lesser extent. Oviparous mammals, or monotremes, do not seem to demonstrate monoparental allele expression. This phylogenic confinement suggests that the evolution of the placenta imposed a selective pressure for the emergence of genomic imprinting. This physiological argument is now complemented by recent genomic evidence facilitated by the sequencing of the platypus genome, a rare modern day case of a monotreme. Analysis of the platypus genome in comparison to eutherian genomes shows a chronological and functional coincidence between the appearance of genomic imprinting and transposable element accumulation. The systematic comparative analyses of genomic sequences in different species is essential for the further understanding of genomic imprinting emergence and divergent evolution along mammalian speciation.

Selective extraction of clonazepam from human plasma and urine samples by molecularly imprinted polymeric beads.

PubMed

Panahi, Homayon Ahmad; Mehramizi, Ali; Ghassemi, Somayeh; Moniri, Elham

2014-03-01

A molecularly imprinted polymer (MIP) based on free-radical polymerization was prepared with 1-(N,N-biscarboxymethyl)amino-3-allylglycerol and N,N-dimethylacrylamide as functional monomers, N,N-methylene diacrylamide as the cross-linker, copper ion-clonazepam as the template and 2,2-azobis(2-methylbutyronitrile) as the initiator. The imprinted polymer was characterized by Fourier transform infrared spectroscopy, elemental analysis, thermo-gravimetric analysis, and SEM. The MIP of agglomerated microparticles with multipores was used for SPE. The imprinted polymer sorbent was selective for clonazepam. The optimum pH and sorption capacity were 5 and 0.18 mg/g at 20C, respectively. The profile of the drug uptake by the sorbent reflects good accessibility of the active sites in the imprinted polymer sorbent. The MIP-SPE was the most feasible technique for the extraction of clonazepam with a high recovery from human plasma and urine samples.

Characterization of molecularly imprinted polymers using a new polar solvent titration method.

PubMed

Song, Di; Zhang, Yagang; Geer, Michael F; Shimizu, Ken D

2014-07-01

A new method of characterizing molecularly imprinted polymers (MIPs) was developed and tested, which provides a more accurate means of identifying and measuring the molecular imprinting effect. In the new polar solvent titration method, a series of imprinted and non-imprinted polymers were prepared in solutions containing increasing concentrations of a polar solvent. The polar solvent additives systematically disrupted the templation and monomer aggregation processes in the prepolymerization solutions, and the extent of disruption was captured by the polymerization process. The changes in binding capacity within each series of polymers were measured, providing a quantitative assessment of the templation and monomer aggregation processes in the imprinted and non-imprinted polymers. The new method was tested using three different diphenyl phosphate imprinted polymers made using three different urea functional monomers. Each monomer had varying efficiencies of templation and monomer aggregation. The new MIP characterization method was found to have several advantages. To independently verify the new characterization method, the MIPs were also characterized using traditional binding isotherm analyses. The two methods appeared to give consistent conclusions. First, the polar solvent titration method is less susceptible to false positives in identifying the imprinting effect. Second, the method is able to differentiate and quantify changes in binding capacity, as measured at a fixed guest and polymer concentration, arising from templation or monomer aggregation processes in the prepolymerization solution. Third, the method was also easy to carry out, taking advantage of the ease of preparing MIPs. Copyright © 2014 John Wiley & Sons, Ltd.

Preparation of High-Efficiency Cytochrome c-Imprinted Polymer on the Surface of Magnetic Carbon Nanotubes by Epitope Approach via Metal Chelation and Six-Membered Ring.

PubMed

Qin, Ya-Ping; Li, Dong-Yan; He, Xi-Wen; Li, Wen-You; Zhang, Yu-Kui

2016-04-27

A novel epitope molecularly imprinted polymer on the surface of magnetic carbon nanotubes (MCNTs@EMIP) was successfully fabricated to specifically recognize target protein cytochrome c (Cyt C) with high performance. The peptides sequences corresponding to the surface-exposed C-terminus domains of Cyt C was selected as epitope template molecule, and commercially available zinc acrylate and ethylene glycol dimethacrylate (EGDMA) were employed as functional monomer and cross-linker, respectively, to synthesize MIP via free radical polymerization. The epitope was immobilized via metal chelation and six-membered ring formed between the functional monomer and the hydroxyl and amino groups of the epitope. The resulting MCNTs@EMIP exhibited specific recognition ability toward target Cyt C including more satisfactory imprinting factor (about 11.7) than that of other reported imprinting methods. In addition, the MCNTs@EMIP demonstrated a high adsorption amount (about 780.0 mg g(-1)) and excellent selectivity. Besides, the magnetic property of the support material made the processes easy and highly efficient by assistance of an external magnetic field. High-performance liquid chromatography analysis of Cyt C in bovine blood real sample and protein mixture indicated that the specificity was not affected by other competitive proteins, which forcefully stated that the MCNTs@EMIP had potential to be applied in bioseparation area. In brief, this study provided a new protocol to detect target protein in complex sample via epitope imprinting approach and surface imprinting strategy.

Magnetic deep eutectic solvents molecularly imprinted polymers for the selective recognition and separation of protein.

PubMed

Liu, Yanjin; Wang, Yuzhi; Dai, Qingzhou; Zhou, Yigang

2016-09-14

A novel and facile magnetic deep eutectic solvents (DES) molecularly imprinted polymers (MIPs) for the selective recognition and separation of Bovine hemoglobin (BHb) was prepared. The new-type DES was adopted as the functional monomer which would bring molecular imprinted technology to a new direction. The amounts of DES were optimized. The obtained magnetic DES-MIPs were characterized with fourier transform infrared spectrometry (FT-IR), thermogravimetric analysis (TGA), field emission scanning electron microscope (FESEM), dynamic light scattering (DLS), elemental analysis and vibrating sample magnetometer (VSM). The results suggested that the imprinted polymers were successfully formed and possessed a charming magnetism. The maximum adsorption capability (Qmax) and dissociation constant (KL) were analyzed by Langmuir isotherms (R(2) = 0.9983) and the value were estimated to be 175.44 mg/g and 0.035 mg/mL for the imprinted particles. And the imprinted particles showed a high imprinting factor of 4.77. In addition, the magnetic DES-MIPs presented outstanding recognition specificity and selectivity so that it can be utilized to separate template protein from the mixture of proteins and real samples. Last but not least, the combination of deep eutectic solvents and molecular imprinted technology in this paper provides a new perspective for the recognition and separation of proteins. Copyright © 2016 Elsevier B.V. All rights reserved.

Visualizing Changes in Cdkn1c Expression Links Early-Life Adversity to Imprint Mis-regulation in Adults.

PubMed

Van de Pette, Mathew; Abbas, Allifia; Feytout, Amelie; McNamara, Gráinne; Bruno, Ludovica; To, Wilson K; Dimond, Andrew; Sardini, Alessandro; Webster, Zoe; McGinty, James; Paul, Eleanor J; Ungless, Mark A; French, Paul M W; Withers, Dominic J; Uren, Anthony; Ferguson-Smith, Anne C; Merkenschlager, Matthias; John, Rosalind M; Fisher, Amanda G

2017-01-31

Imprinted genes are regulated according to parental origin and can influence embryonic growth and metabolism and confer disease susceptibility. Here, we designed sensitive allele-specific reporters to non-invasively monitor imprinted Cdkn1c expression in mice and showed that expression was modulated by environmental factors encountered in utero. Acute exposure to chromatin-modifying drugs resulted in de-repression of paternally inherited (silent) Cdkn1c alleles in embryos that was temporary and resolved after birth. In contrast, deprivation of maternal dietary protein in utero provoked permanent de-repression of imprinted Cdkn1c expression that was sustained into adulthood and occurred through a folate-dependent mechanism of DNA methylation loss. Given the function of imprinted genes in regulating behavior and metabolic processes in adults, these results establish imprinting deregulation as a credible mechanism linking early-life adversity to later-life outcomes. Furthermore, Cdkn1c-luciferase mice offer non-invasive tools to identify factors that disrupt epigenetic processes and strategies to limit their long-term impact. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

Quantum-dots-encoded-microbeads based molecularly imprinted polymer.

PubMed

Liu, Yixi; Liu, Le; He, Yonghong; He, Qinghua; Ma, Hui

2016-03-15

Quantum dots encoded microbeads have various advantages such as large surface area, superb optical properties and the ability of multiplexing. Molecularly imprinted polymer that can mimic the natural recognition entities has high affinity and selectivity for the specific analyte. Here, the concept of utilizing the quantum dots encoded microbeads as the supporting material and the polydopamine as the functional monomer to form the core-shell molecular imprinted polymer was proposed for the first time. The resulted imprinted polymer can provide various merits: polymerization can complete in aqueous environment; fabrication procedure is facile and universal; the obvious economic advantage; the thickness of the imprinting layer is highly controllable; polydopamine coating can improve the biocompatibility of the quantum dot encoded microbeads. The rabbit IgG binding and flow cytometer experiment result showed the distinct advantages of this strategy: cost-saving, facile and fast preparation procedure. Most importantly, the ability for the multichannel detection, which makes the imprinted polydopamine modified encoded-beads very attractive in protein pre-concentration, recognition, separation and biosensing. Copyright © 2015 Elsevier B.V. All rights reserved.

Molecularly imprinted polymer for selective extraction of malachite green from seawater and seafood coupled with high-performance liquid chromatographic determination.

PubMed

Lian, Ziru; Wang, Jiangtao

2012-12-01

In this paper, a highly selective sample cleanup procedure combining molecular imprinting technique (MIT) and solid-phase extraction (SPE) was developed for the isolation of malachite green in seawater and seafood samples. The molecularly imprinted polymer (MIP) was prepared using malachite green as the template molecule, methacrylic acid as the functional monomer and ethylene glycol dimethacrylate as the cross-linking monomer. The imprinted polymer and non-imprinted polymer were characterized by scanning electron microscope and static adsorption experiments. The MIP showed a high adsorption capacity and was used as selective sorbent for the SPE of malachite green. An off-line molecularly imprinted solid-phase extraction (MISPE) method followed by high-performance liquid chromatography with diodearray detection for the analysis of malachite green in seawater and seafood samples was also established. Finally, five samples were determined. The results showed that malachite green concentration in one seawater sample was at 1.30 μg L⁻¹ and the RSD (n=3) was 4.15%. Crown Copyright © 2012. Published by Elsevier Ltd. All rights reserved.

Imprinting continuously varying topographical structure onto large-aperture optical surfaces using magnetorheological finishing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Menapace, J A; Davis, P J; Dixit, S

2007-03-07

Over the past four years we have advanced Magnetorheological Finishing (MRF) techniques and tools to imprint complex continuously varying topographical structures onto large-aperture (430 x 430 mm) optical surfaces. These optics, known as continuous phase plates (CPPs), are important for high-power laser applications requiring precise manipulation and control of beam-shape, energy distribution, and wavefront profile. MRF's unique deterministic-sub-aperture polishing characteristics make it possible to imprint complex topographical information onto optical surfaces at spatial scale-lengths approaching 1 mm and surface peak-to-valleys as high as 22 {micro}m. During this discussion, we will present the evolution of the MRF imprinting technology and themore » MRF tools designed to manufacture large-aperture 430 x 430 mm CPPs. Our results will show how the MRF removal function impacts and limits imprint fidelity and what must be done to arrive at a high-quality surface. We also present several examples of this imprinting technology for fabrication of phase correction plates and CPPs for use in high-power laser applications.« less

Vitamin-caused faulty perinatal hormonal imprinting and its consequences in adult age.

PubMed

Csaba, G

2017-09-01

Lipid-soluble vitamins (vitamins A, D, E, and K) are actually hormones (exohormones), as they can be directly bound by hormone receptors or are in connection with molecules, which influence hormone receptors. Vitamin D is a transition between endo- and exohormones and the possibility of similar situation in case of other lipid-soluble hormones is discussed. The perinatal exposition with these "vitamins" can cause faulty perinatal hormonal imprinting with similar consequences as the faulty imprinting by the synthetic endohormones, members of the same hormone family or industrial, communal, or medical endocrine disruptors. The faulty imprinting leads to late (lifelong) consequences with altered hormone binding by receptors, altered sexuality, brain function, immunity, bone development, and fractures, etc. In addition, as hormonal imprinting is an epigenetic process, the effect of a single exposure by fat-soluble vitamins is inherited to the progeny generations. As vitamins are handled differently from hormones; however, perinatal treatments take place frequently and sometimes it is forced, the negative late effect of faulty perinatal vitamin-caused hormonal imprinting must be considered.

Hierarchical templating in deposition of semi-covalently imprinted inverse opal polythiophene film for femtomolar determination of human serum albumin.

PubMed

Dabrowski, Marcin; Cieplak, Maciej; Sharma, Piyush Sindhu; Borowicz, Pawel; Noworyta, Krzysztof; Lisowski, Wojciech; D'Souza, Francis; Kuhn, Alexander; Kutner, Wlodzimierz

2017-08-15

Nanostructured artificial receptor materials with unprecedented hierarchical structure for determination of human serum albumin (HSA) are designed and fabricated. For that purpose a new hierarchical template is prepared. This template allowed for simultaneous structural control of the deposited molecularly imprinted polymer (MIP) film on three length scales. A colloidal crystal templating with optimized electrochemical polymerization of 2,3'-bithiophene enables deposition of an MIP film in the form of an inverse opal. Thickness of the deposited polymer film is precisely controlled with the number of current oscillations during potentiostatic deposition of the imprinted poly(2,3'-bithiophene) film. Prior immobilization of HSA on the colloidal crystal allows formation of molecularly imprinted cavities exclusively on the internal surface of the pores. Furthermore, all binding sites are located on the surface of the imprinted cavities at locations corresponding to positions of functional groups present on the surface of HSA molecules due to prior derivatization of HSA molecules with appropriate functional monomers. This synergistic strategy results in a material with superior recognition performance. Integration of the MIP film as a recognition unit with a sensitive extended-gate field-effect transistor (EG-FET) transducer leads to highly selective HSA determination in the femtomolar concentration range. Copyright © 2017 Elsevier B.V. All rights reserved.

Molecularly Imprinted Microrods via Mesophase Polymerization.

PubMed

Parisi, Ortensia Ilaria; Scrivano, Luca; Candamano, Sebastiano; Ruffo, Mariarosa; Vattimo, Anna Francesca; Spanedda, Maria Vittoria; Puoci, Francesco

2017-12-28

The aim of the present research work was the synthesis of molecularly imprinted polymers (MIPs) with a rod-like geometry via "mesophase polymerization". The ternary lyotropic system consisting of sodium dodecyl sulfate (SDS), water, and decanol was chosen to prepare a hexagonal mesophase to direct the morphology of the synthesized imprinted polymers using theophylline, methacrylic acid, and ethylene glycol dimethacrylate as a drug model template, a functional monomer, and a crosslinker, respectively. The obtained molecularly imprinted microrods (MIMs) were assessed by performing binding experiments and in vitro release studies, and the obtained results highlighted good selective recognition abilities and sustained release properties. In conclusion, the adopted synthetic strategy involving a lyotropic mesophase system allows for the preparation of effective MIPs characterized by a rod-like morphology.

[Revaluation of the concept of developmental abnormality: the importance of faulty perinatal imprinting].

PubMed

Csaba, György

2015-07-12

The classic definition of developmental abnormalities referred to malformations observed at birth. Later the functional teratogenicity was also recognized and accepted, which can be revealed in functional abnormalities caused by harms during the intrauterine development and can be manifested at any time of life. However, the ontogeny is not closed with the birth, because some systems or organs are developing for a long time after it, and can be influenced by different factors. From this aspect the perinatal period is especially important when the mutual adjustment of the receptor-hormone system is taking place and the hormonal imprinting develops. If this is faulty, it influences the hormone binding capacity of receptors that has consequences for life. The faulty hormonal imprinting is functionally teratogen; it provokes a fault up to the level of a malformation and aggravated with its heredity to the progenies. False imprinting is provoked (in animal experiments, proportioning to human doses) by drugs acting at receptor level, as oxytocin, steroid hormone analogues (pregnancy protectors, oral contraceptives, surfactants), vitamin A and D, environmental pollutant endocrine disruptors (benzpyrene, bisphenol A, pesticides, herbicides) and certain soybean components, etc. From this aspect these are functional teratogens, and their evasion in prevention as well as therapy seems to be vital. This means that the concept of developmental abnormality must be broadened, as developmental abnormalities: 1.) can originate not only in the intrauterine period, but also perinatally or even later, 2.) it can be manifested at any time of life, 3.) it can be present in a latent form which can be activated by inner or outer environmental factors, 4.) the faulty hormonal imprinting is a teratogen factor.

Expression at the imprinted dlk1-gtl2 locus is regulated by proneural genes in the developing telencephalon.

PubMed

Seibt, Julie; Armant, Olivier; Le Digarcher, Anne; Castro, Diogo; Ramesh, Vidya; Journot, Laurent; Guillemot, François; Vanderhaeghen, Pierre; Bouschet, Tristan

2012-01-01

Imprinting is an epigenetic mechanism that restrains the expression of about 100 genes to one allele depending on its parental origin. Several imprinted genes are implicated in neurodevelopmental brain disorders, such as autism, Angelman, and Prader-Willi syndromes. However, how expression of these imprinted genes is regulated during neural development is poorly understood. Here, using single and double KO animals for the transcription factors Neurogenin2 (Ngn2) and Achaete-scute homolog 1 (Ascl1), we found that the expression of a specific subset of imprinted genes is controlled by these proneural genes. Using in situ hybridization and quantitative PCR, we determined that five imprinted transcripts situated at the Dlk1-Gtl2 locus (Dlk1, Gtl2, Mirg, Rian, Rtl1) are upregulated in the dorsal telencephalon of Ngn2 KO mice. This suggests that Ngn2 influences the expression of the entire Dlk1-Gtl2 locus, independently of the parental origin of the transcripts. Interestingly 14 other imprinted genes situated at other imprinted loci were not affected by the loss of Ngn2. Finally, using Ngn2/Ascl1 double KO mice, we show that the upregulation of genes at the Dlk1-Gtl2 locus in Ngn2 KO animals requires a functional copy of Ascl1. Our data suggest a complex interplay between proneural genes in the developing forebrain that control the level of expression at the imprinted Dlk1-Gtl2 locus (but not of other imprinted genes). This raises the possibility that the transcripts of this selective locus participate in the biological effects of proneural genes in the developing telencephalon.

Expression at the Imprinted Dlk1-Gtl2 Locus Is Regulated by Proneural Genes in the Developing Telencephalon

PubMed Central

Seibt, Julie; Armant, Olivier; Le Digarcher, Anne; Castro, Diogo; Ramesh, Vidya; Journot, Laurent; Guillemot, François; Vanderhaeghen, Pierre; Bouschet, Tristan

2012-01-01

Imprinting is an epigenetic mechanism that restrains the expression of about 100 genes to one allele depending on its parental origin. Several imprinted genes are implicated in neurodevelopmental brain disorders, such as autism, Angelman, and Prader-Willi syndromes. However, how expression of these imprinted genes is regulated during neural development is poorly understood. Here, using single and double KO animals for the transcription factors Neurogenin2 (Ngn2) and Achaete-scute homolog 1 (Ascl1), we found that the expression of a specific subset of imprinted genes is controlled by these proneural genes. Using in situ hybridization and quantitative PCR, we determined that five imprinted transcripts situated at the Dlk1-Gtl2 locus (Dlk1, Gtl2, Mirg, Rian, Rtl1) are upregulated in the dorsal telencephalon of Ngn2 KO mice. This suggests that Ngn2 influences the expression of the entire Dlk1-Gtl2 locus, independently of the parental origin of the transcripts. Interestingly 14 other imprinted genes situated at other imprinted loci were not affected by the loss of Ngn2. Finally, using Ngn2/Ascl1 double KO mice, we show that the upregulation of genes at the Dlk1-Gtl2 locus in Ngn2 KO animals requires a functional copy of Ascl1. Our data suggest a complex interplay between proneural genes in the developing forebrain that control the level of expression at the imprinted Dlk1-Gtl2 locus (but not of other imprinted genes). This raises the possibility that the transcripts of this selective locus participate in the biological effects of proneural genes in the developing telencephalon. PMID:23139813

Shape recognition of microbial cells by colloidal cell imprints

NASA Astrophysics Data System (ADS)

Borovička, Josef; Stoyanov, Simeon D.; Paunov, Vesselin N.

2013-08-01

We have engineered a class of colloids which can recognize the shape and size of targeted microbial cells and selectively bind to their surfaces. These imprinted colloid particles, which we called ``colloid antibodies'', were fabricated by partial fragmentation of silica shells obtained by templating the targeted microbial cells. We successfully demonstrated the shape and size recognition between such colloidal imprints and matching microbial cells. High percentage of binding events of colloidal imprints with the size matching target particles was achieved. We demonstrated selective binding of colloidal imprints to target microbial cells in a binary mixture of cells of different shapes and sizes, which also resulted in high binding selectivity. We explored the role of the electrostatic interactions between the target cells and their colloid imprints by pre-coating both of them with polyelectrolytes. Selective binding occurred predominantly in the case of opposite surface charges of the colloid cell imprint and the targeted cells. The mechanism of the recognition is based on the amplification of the surface adhesion in the case of shape and size match due to the increased contact area between the target cell and the colloidal imprint. We also tested the selective binding for colloid imprints of particles of fixed shape and varying sizes. The concept of cell recognition by colloid imprints could be used for development of colloid antibodies for shape-selective binding of microbes. Such colloid antibodies could be additionally functionalized with surface groups to enhance their binding efficiency to cells of specific shape and deliver a drug payload directly to their surface or allow them to be manipulated using external fields. They could benefit the pharmaceutical industry in developing selective antimicrobial therapies and formulations.

[Study on the choice of functional monomer before preparation of myclobutanil molecularly imprinted polymer].

PubMed

Gao, Wen-Hui; Liu, Bo; Li, Xing-Feng; Han, Jun-Hua; Jia, Ying-Min

2014-03-01

To prepare myclobutanil molecularly imprinted polymer, a method was established for the choice of the appropriate functional monomer and its dosage. UV spectra was applied to study the combination form, the effect intensity, the optimal concentration ratio and the numbers of binding sites between myclobutanil and methyl acrylic acid (MAA) or acrylamide (AM) functional monomer. The results showed that hydrogen-bonding interaction could be formed between myclobutanil and methyl acrylic acid (MAA) or acrylamide (AM) functional monomer. The pi electron of the triazole ring conjugated double bond in my clobutanil could transit to pi* conjugate antibonding orbital when it absorbed energy. The formation of hydrogen bond could make pi-->pi* absorption band transit. Maximum absorption wavelength produced red shift with the increase in the functional monomer concentration in the system. The research revealed that the optimal concentration ratios between myclobutanil and the two monomers were c(M):c(MAA) = 1:4, c(M):c(AM) = 1:2. Myclobutanil and the both the functional monomers had the bonding ability, and strong bonding force. The prepared molecularly imprinted polymer using AM as a functional monomer had better stability and specificity of recognition for myclobutanil.

Rapid degradation of Congo red by molecularly imprinted polypyrrole-coated magnetic TiO2 nanoparticles in dark at ambient conditions.

PubMed

Wei, Shoutai; Hu, Xiaolei; Liu, Hualong; Wang, Qiang; He, Chiyang

2015-08-30

A novel molecularly imprinted polymer (MIP)-coated magnetic TiO2 nanocomposite was prepared, using methyl orange (MO) as the dummy template and pyrrole as functional monomer, for degradation of Congo red (CR). The nanocomposite was characterized by Fourier transform infrared spectroscopy, thermo-gravimetric analysis, X-ray diffraction, transmission electron microscopy, and vibrating sample magnetometer. The imprinting efficiency of the imprinted nanoparticles was investigated by static binding test, and their degradation ability toward CR was also studied. Moreover, the effects of pH, temperature, dissolved oxygen and oscillation rate on degradation rate of CR were investigated. Results showed that the imprinted nanocomposite had higher adsorption ability for MO compared with the non-imprinted one. Moreover, it could degrade CR rapidly in dark at room temperature and atmospheric pressure and could be recycled easily by a magnet with a good reusability. A degradation mechanism was proposed according to LC-MS analysis of degradation products of CR. The new imprinted nanoparticles showed high catalytic activity at ambient conditions without light illumination and additional chemicals, and therefore, it can be potentially applied to the rapid, "green" and low-cost degradation of CR in industrial printing and dyeing wastewater. Copyright © 2015 Elsevier B.V. All rights reserved.

HPLC imprinted-stationary phase prepared by precipitation polymerisation for the determination of thiabendazole in fruit.

PubMed

Turiel, E; Tadeo, J L; Cormack, P A G; Martin-Esteban, A

2005-12-01

A molecularly imprinted polymer (MIP) tailored for the HPLC determination of the fungicide thiabendazole (TBZ) has been synthesised in one single preparative step by precipitation polymerisation in an acetonitrile/toluene co-solvent, using TBZ as template molecule, methacrylic acid as functional monomer and divinylbenzene-80 as crosslinker. The imprinted polymer particulates obtained were characterised by scanning electron microscopy and nitrogen sorption porosimetry. These analyses showed clearly that spherical polymer particulates (polymer microspheres) with narrow size distributions (average particle diameter approximately 3.5 microm) and well-developed pore structures had been produced. The imprinted microspheres were packed into a stainless steel HPLC column (50 x 4.6 mm id) and evaluated as an imprinted stationary phase. The imprinting effect was demonstrated clearly, i.e., the column was observed to bind TBZ selectively, and the effect of different chromatographic parameters (e.g., temperature, flow-rate and elution solvents) on TBZ retention/elution studied. Under optimised conditions, the TBZ-imprinted column was used for the HPLC-fluorescence (HPLC-F) determination of TBZ directly from orange (both whole fruit and juice), lemon, grape and strawberry extracts at low concentration levels in less than 15 min, without any need for a clean-up step in the analytical protocol.

Recognition of oxytocin by capillary electrochromatography with monolithic tetrapeptide-imprinted polymer used as the stationary phase.

PubMed

Zheng, Chao; Liu, Zhaosheng; Gao, Ruyu; Zhang, Lihua; Zhang, Yukui

2007-07-01

Using YPLG (Tyr-Pro-Leu-Gly), a tetrapeptide, as the template, an imprinted monolithic column was prepared and applied to the selective recognition of oxytocin based on the epitope approach and capillary electrochromatography (CEC). By optimizing the polymerization solution in terms of functional monomer, cross-linking reagent, porogen, and imprinted template via CEC evaluations of synthesized columns, an imprinted monolith with good recognition capacity (the imprinting factors for YPLG and oxytocin were 4.499 and 4.013, respectively) and high column efficiency (theoretical plates for YPLG and oxytocin were 22,995 plates/m and 16,952 plates/m, respectively) was achieved. In addition, the effects of various experimental parameters on the recognition of oxytocin, including the organic modifier content, the buffer concentration, and the pH value, were studied systematically. Furthermore, a mixture of oxytocin and other proteins was analyzed using this monolithic CEC column, and oxytocin was eluted much more slowly than other large biomolecules, which demonstrated the high selective recognition ability of such an imprinted monolith for oxytocin with PLG (Pro-Leu-Gly) as the epitope. Figure Separation of a mixture of oxytocin, BSA, bovine hemoglobin, ovalbumin, and lysozyme on the open column, the blank monolithic column, and the monolithic YPLG-imprinted column.

Metal chelation dual-template epitope imprinting polymer via distillation-precipitation polymerization for recognition of porcine serum albumin.

PubMed

Qin, Ya-Ping; Wang, Hai-Yan; He, Xi-Wen; Li, Wen-You; Zhang, Yu-Kui

2018-08-01

A novel dual-template epitope imprinting polymer coated on magnetic carbon nanotubes (MCNTs@D-EMIP) was successfully prepared for specific recognition of porcine serum albumin (PSA) via dual-template epitope imprinting, metal chelation imprinting and distillation-precipitation polymerization (DPP). C-terminal peptides and N-terminal peptides of PSA were selected as templates simultaneously, and zinc acrylate and ethylene glycol dimethacrylate (EGDMA) were used as functional monomer and cross-linker, respectively. The epitope templates were immobilized by metal chelation and six-membered ring formed with zinc acrylate. Finally, MCNTs@D-EMIP was synthesized by DPP in only 30 min, which was much shorter than those of other polymerization methods. The prepared MCNTs@D-EMIP displayed specific recognition ability toward PSA and its adsorption amount and imprinting factor were 45.05 mg g -1 and 4.50, which were much higher than those of single template epitope imprinting polymers. Besides, high-performance liquid chromatography (HPLC) analysis of PSA in porcine blood serum real sample indicated that the specificity was not affected by other competitive proteins, which forcefully stated that the MCNTs@D-EMIP had potential to be applied in bio-separation area. In addition, the results of cross-reactivity experiment proved that this strategy had generality to prepare dual-template epitope imprinting polymer for recognition of target protein. In summary, this study provided an efficient protocol to recognize target protein in complex sample via dual-template epitope imprinting approach, metal chelation imprinting and distillation-precipitation polymerization. Copyright © 2018 Elsevier B.V. All rights reserved.

Experimental Functional Analysis of Aggression in Children with Angelman Syndrome

ERIC Educational Resources Information Center

Strachan, Rachel; Shaw, Rebecca; Burrow, Caroline; Horsler, Kate; Allen, Debbie; Oliver, Chris

2009-01-01

Background: Kinship theory suggests that genomic imprinting could account for phenotypic behaviors that increase (in the case of Angelman syndrome) or decrease (for Prader-Willi syndrome) the drive to access social resources (adult contact) depending on the imprinting parent-of-origin. Difficult to manage behaviors, such as aggression that is…

Molecular Imprinted Polymer of Methacrylic Acid Functionalised β-Cyclodextrin for Selective Removal of 2,4-Dichlorophenol

PubMed Central

Surikumaran, Hemavathy; Mohamad, Sharifah; Sarih, Norazilawati Muhamad

2014-01-01

This work describes methacrylic acid functionalized β-cyclodextrin (MAA-βCD) as a novel functional monomer in the preparation of molecular imprinted polymer (MIP MAA-βCD) for the selective removal of 2,4-dichlorophenol (2,4-DCP). The polymer was characterized using Fourier Transform Infrared (FTIR) spectroscopy, Brunauer-Emmett-Teller (BET) and Field Emission Scanning Electron Microscopy (FESEM) techniques. The influence of parameters such as solution pH, contact time, temperature and initial concentrations towards removal of 2,4-DCP using MIP MAA-βCD have been evaluated. The imprinted material shows fast kinetics and the optimum pH for removal of 2,4-DCP is pH 7. Compared with the corresponding non-imprinted polymer (NIP MAA-βCD), the MIP MAA-βCD exhibited higher adsorption capacity and outstanding selectivity towards 2,4-DCP. Freundlich isotherm best fitted the adsorption equilibrium data of MIP MAA-βCD and the kinetics followed a pseudo-second-order model. The calculated thermodynamic parameters showed that adsorption of 2,4-DCP was spontaneous and exothermic under the examined conditions. PMID:24727378

The Development of Animal Behavior: From Lorenz to Neural Nets

NASA Astrophysics Data System (ADS)

Bolhuis, Johan J.

In the study of behavioral development both causal and functional approaches have been used, and they often overlap. The concept of ontogenetic adaptations suggests that each developmental phase involves unique adaptations to the environment of the developing animal. The functional concept of optimal outbreeding has led to further experimental evidence and theoretical models concerning the role of sexual imprinting in the evolutionary process of sexual selection. From a causal perspective it has been proposed that behavioral ontogeny involves the development of various kinds of perceptual, motor, and central mechanisms and the formation of connections among them. This framework has been tested for a number of complex behavior systems such as hunger and dustbathing. Imprinting is often seen as a model system for behavioral development in general. Recent advances in imprinting research have been the result of an interdisciplinary effort involving ethology, neuroscience, and experimental psychology, with a continual interplay between these approaches. The imprinting results are consistent with Lorenz' early intuitive suggestions and are also reflected in the architecture of recent neural net models.

Deletion of the Imprinted Gene Grb10 Promotes Hematopoietic Stem Cell Self-Renewal and Regeneration.

PubMed

Yan, Xiao; Himburg, Heather A; Pohl, Katherine; Quarmyne, Mamle; Tran, Evelyn; Zhang, Yurun; Fang, Tiancheng; Kan, Jenny; Chao, Nelson J; Zhao, Liman; Doan, Phuong L; Chute, John P

2016-11-01

Imprinted genes are differentially expressed by adult stem cells, but their functions in regulating adult stem cell fate are incompletely understood. Here we show that growth factor receptor-bound protein 10 (Grb10), an imprinted gene, regulates hematopoietic stem cell (HSC) self-renewal and regeneration. Deletion of the maternal allele of Grb10 in mice (Grb10 m/+ mice) substantially increased HSC long-term repopulating capacity, as compared to that of Grb10 +/+ mice. After total body irradiation (TBI), Grb10 m/+ mice demonstrated accelerated HSC regeneration and hematopoietic reconstitution, as compared to Grb10 +/+ mice. Grb10-deficient HSCs displayed increased proliferation after competitive transplantation or TBI, commensurate with upregulation of CDK4 and Cyclin E. Furthermore, the enhanced HSC regeneration observed in Grb10-deficient mice was dependent on activation of the Akt/mTORC1 pathway. This study reveals a function for the imprinted gene Grb10 in regulating HSC self-renewal and regeneration and suggests that the inhibition of Grb10 can promote hematopoietic regeneration in vivo. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

Biosensor-assisted selection of optimal parameters for designing molecularly imprinted polymers selective to phosmet insecticide.

PubMed

Aftim, Nadin; Istamboulié, Georges; Piletska, Elena; Piletsky, Sergey; Calas-Blanchard, Carole; Noguer, Thierry

2017-11-01

Molecularly imprinted polymers (MIPs) for phosmet insecticide were synthesized by batch polymerization. The affinity of functional monomers to phosmet was tested using an original method involving an electrochemical biosensor based on acetylcholinesterase inhibition. It was demonstrated that association of phosmet with appropriate functional monomers resulted in a decrease of enzyme inhibition. Using this method, it was shown that N,N-methylenebis(acrylamide) displayed the highest interactions with phosmet using DMSO as solvent. These results were in good accordance with those obtained by conventional computational modeling. Molecularly imprinted polymers (MIPs) and non-imprinted polymers (NIPs) were synthesized and adsorption isotherms were studied to describe their interaction with phosmet. Freundlich isotherm was able to fit phosmet adsorption on MIPs with good agreement (R 2 = 0.9). The pre-exponential factor K F determined for MIPs was 1.439mg (1-N) g -1 L N , more that 10 times higher than for NIPs (0.125mg (1-N) g -1 . L N ), indicating an increase of binding sites number and average affinity. Copyright © 2017 Elsevier B.V. All rights reserved.

Molecularly imprinted polymer online solid-phase extraction coupled with high-performance liquid chromatography-UV for the determination of three sulfonamides in pork and chicken.

PubMed

He, Jinxing; Wang, Shuo; Fang, Guozhen; Zhu, Huaping; Zhang, Yan

2008-05-14

A selective imprinted amino-functionalized silica gel sorbent was prepared by combining a surface molecular imprinting technique with a sol-gel process for online solid-phase extraction-HPLC determination of three trace sulfonamides in pork and chicken muscle. The imprinted functionalized silica gel sorbent exhibited selectivity and fast kinetics for the adsorption and desorption of sulfonamides. With a sample loading flow rate of 4 mL min (-1) for 12.5 min, enhancement factors and detection limits for three sulfonamides ( S/ N = 3) were achieved. The precision (RSD) for nine replicate online sorbent extractions of 5 microg L (-1) sulfonamides was less than 4.5%. The sorbent also offered good linearity ( r (2) > 0.99) for online solid-phase extraction of trace levels of sulfonamides. The method was applied to the determination of sulfonamides in pork and chicken muscle samples. The prepared polymer sorbent shows promise for online solid-phase extraction for HPLC determination of trace levels of sulfonamides in pork and chicken samples.

Gas Sensors Based on Molecular Imprinting Technology.

PubMed

Zhang, Yumin; Zhang, Jin; Liu, Qingju

2017-07-04

Molecular imprinting technology (MIT); often described as a method of designing a material to remember a target molecular structure (template); is a technique for the creation of molecularly imprinted polymers (MIPs) with custom-made binding sites complementary to the target molecules in shape; size and functional groups. MIT has been successfully applied to analyze; separate and detect macromolecular organic compounds. Furthermore; it has been increasingly applied in assays of biological macromolecules. Owing to its unique features of structure specificity; predictability; recognition and universal application; there has been exploration of the possible application of MIPs in the field of highly selective gas sensors. In this present study; we outline the recent advances in gas sensors based on MIT; classify and introduce the existing molecularly imprinted gas sensors; summarize their advantages and disadvantages; and analyze further research directions.

Temporal and developmental requirements for the Prader–Willi imprinting center

PubMed Central

DuBose, Amanda J.; Smith, Emily Y.; Johnstone, Karen A.; Resnick, James L.

2012-01-01

Imprinted gene expression associated with Prader–Willi syndrome (PWS) and Angelman syndrome (AS) is controlled by two imprinting centers (ICs), the PWS-IC and the AS-IC. The PWS-IC operates in cis to activate transcription of genes that are expressed exclusively from the paternal allele. We have created a conditional allele of the PWS-IC to investigate its developmental activity. Deletion of the paternal PWS-IC in the embryo before implantation abolishes expression of the paternal-only genes in the neonatal brain. Surprisingly, deletion of the PWS-IC in early brain progenitors does not affect the subsequent imprinted status of PWS/AS genes in the newborn brain. These results indicate that the PWS-IC functions to protect the paternal epigenotype at the epiblast stage of development but is dispensable thereafter. PMID:22331910

Synthesis and application of surface-imprinted activated carbon sorbent for solid-phase extraction and determination of copper (II)

NASA Astrophysics Data System (ADS)

Li, Zhenhua; Li, Jingwen; Wang, Yanbin; Wei, Yajun

2014-01-01

A new Cu(II)-imprinted amino-functionalized activated carbon sorbent was prepared by a surface imprinting technique for selective solid-phase extraction (SPE) of Cu(II) prior to its determination by inductively coupled plasma atomic emission spectrometry (ICP-AES). Experimental conditions for effective adsorption of Cu(II) were optimized with respect to different experimental parameters using static and dynamic procedures in detail. Compared with non-imprinted sorbent, the ion-imprinted sorbent had higher selectivity and adsorption capacity for Cu(II). The maximum static adsorption capacity of the ion-imprinted and non-imprinted sorbent for Cu(II) was 26.71 and 6.86 mg g-1, respectively. The relatively selectivity factor values (αr) of Cu(II)/Zn(II), Cu(II)/Ni(II), Cu(II)/Co(II) and Cu(II)/Pb(II) were 166.16, 50.77, 72.26 and 175.77, respectively, which were greater than 1. Complete elution of the adsorbed Cu(II) from Cu(II)-imprinted sorbent was carried out using 2 mL of 0.1 mol L-1 EDTA solution. The relative standard deviation of the method was 2.4% for eleven replicate determinations. The method was validated for the analysis by two certified reference materials (GBW 08301, GBW 08303), the results obtained is in good agreement with standard values. The developed method was also successfully applied to the determination of trace copper in natural water samples with satisfactory results.

Synthesis and application of surface-imprinted activated carbon sorbent for solid-phase extraction and determination of copper (II).

PubMed

Li, Zhenhua; Li, Jingwen; Wang, Yanbin; Wei, Yajun

2014-01-03

A new Cu(II)-imprinted amino-functionalized activated carbon sorbent was prepared by a surface imprinting technique for selective solid-phase extraction (SPE) of Cu(II) prior to its determination by inductively coupled plasma atomic emission spectrometry (ICP-AES). Experimental conditions for effective adsorption of Cu(II) were optimized with respect to different experimental parameters using static and dynamic procedures in detail. Compared with non-imprinted sorbent, the ion-imprinted sorbent had higher selectivity and adsorption capacity for Cu(II). The maximum static adsorption capacity of the ion-imprinted and non-imprinted sorbent for Cu(II) was 26.71 and 6.86 mg g(-1), respectively. The relatively selectivity factor values (αr) of Cu(II)/Zn(II), Cu(II)/Ni(II), Cu(II)/Co(II) and Cu(II)/Pb(II) were 166.16, 50.77, 72.26 and 175.77, respectively, which were greater than 1. Complete elution of the adsorbed Cu(II) from Cu(II)-imprinted sorbent was carried out using 2 mL of 0.1 mol L(-1) EDTA solution. The relative standard deviation of the method was 2.4% for eleven replicate determinations. The method was validated for the analysis by two certified reference materials (GBW 08301, GBW 08303), the results obtained is in good agreement with standard values. The developed method was also successfully applied to the determination of trace copper in natural water samples with satisfactory results. Copyright © 2013 Elsevier B.V. All rights reserved.

Pyrogallol-imprinted polymers with methyl methacrylate via precipitation polymerization

NASA Astrophysics Data System (ADS)

Mehamod, Faizatul Shimal; Othman, Nor Amira; Bulat, Ku Halim Ku; Suah, Faiz Bukhari Mohd

2018-06-01

Molecular simulation techniques are important to study the understanding of chemical and physical properties of any material. Computational modeling is considered as time reducer in finding the best recipes for Molecularly-Imprinted Polymers (MIPs). In this study, Pyrogallol-imprinted polymers (PIP) and non-imprinted polymers (NIPs) were synthesized via precipitation polymerization using Pyrogallol (Py), methyl methacrylate (MMA), divinylbenzene (DVB) as template, functional monomer and cross-linker, respectively. The recipe was according to the results from computational techniques. The synthesized PIP and NIPs were characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), Brunauer-Emmett-Teller (BET) and UV-visible spectroscopy (UV-vis). Studies on adsorption isotherm showed that PIP and NIPs follow Scatchard isotherm models. Sorption kinetic study found that PIP and NIPs follow pseudo-second order which indicates the rate-limiting step is the surface adsorption. The imprinting factor of PIP was determined by selectivity study and showed the value of k >1, which proved that PIP was selective toward Pyrogallol compared to NIP.

Halloysite-based dopamine-imprinted polymer for selective protein capture.

PubMed

Zhu, Xiaohong; Li, Hui; Liu, Hui; Peng, Wei; Zhong, Shian; Wang, Yan

2016-06-01

We describe a facile, general, and highly efficient approach to obtain polydopamine-coated molecularly imprinted polymer based on halloysite nanotubes for bovine serum albumin. The method combined surface molecular imprinting and one-step immobilized template technique. Hierarchically structured polymer was prepared in physiological conditions adopting dopamine as functional monomer. A thin layer of polydopamine can be coated on the surface of amino-modified halloysite nanotubes by self-polymerization, and the thickness of the imprinted shells can be controlled by the mass ratio of matrix and dopamine. The polymer was characterized by Fourier transform infrared spectrometry, transmission electron microscopy, and thermogravimetric analysis. The prepared material showed high binding capacity (45.4 mg/g) and specific recognition behavior toward the template protein. In addition, stability and regeneration analyses indicated that the imprinted polymer exhibited excellent reusability (relative standard deviation < 9% for batch-to-batch evaluation). Therefore, the developed polymer is effective for protein recognition and separation. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Innovative Design and Performance Evaluation of Bionic Imprinting Toothed Wheel.

PubMed

Zhang, Zhihong; Wang, Xiaoyang; Tong, Jin; Stephen, Carr

2018-01-01

A highly efficient soil-burrowing dung beetle possesses an intricate outer contour curve on its foreleg end-tooth. This study was carried out based on evidence that this special outer contour curve has the potential of reducing soil penetration resistance and could enhance soil-burrowing efficiency. A toothed wheel is a typical agricultural implement for soil imprinting, to increase its working efficiency; the approach of the bionic geometrical structure was utilized to optimize the innovative shape of imprinting toothed wheel. Characteristics in the dung beetle's foreleg end-tooth were extracted and studied by the edge detection technique. Then, this special outer contour curve was modeled by a nine-order polynomial function and used for the innovative design of imprinting the tooth's cutting edge. Both the conventional and bionic teeth were manufactured, and traction tests in a soil bin were conducted. Taking required draft force and volume of imprinted microbasin as the evaluating indexes, operating efficiency and quality of different toothed wheels were compared and investigated. Results indicate that compared with the conventional toothed wheel, a bionic toothed wheel possesses a better forward resistance reduction property against soil and, meanwhile, can enhance the quality of soil imprinting by increasing the volume of the created micro-basin.

Exploiting β-Cyclodextrin in Molecular Imprinting for Achieving Recognition of Benzylparaben in Aqueous Media

PubMed Central

Asman, Saliza; Mohamad, Sharifah; Muhamad Sarih, Norazilawati

2015-01-01

The molecularly imprinted polymer (MIP) based on methacrylic acid functionalized β-cyclodextrin (MAA-β-CD) monomer was synthesized for the purpose of selective recognition of benzylparaben (BzP). The MAA-β-CD monomer was produced by bridging a methacrylic acid (MAA) and β-cyclodextrin (β-CD) using toluene-2,4-diisocyanate (TDI) by reacting the –OH group of MAA and one of the primary –OH groups of β-CD. This monomer comprised of triple interactions that included an inclusion complex, π–π interaction, and hydrogen bonding. To demonstrate β-CD performance in MIPs, two MIPs were prepared; molecularly imprinted polymer-methacrylic acid functionalized β-cyclodextrin, MIP(MAA-β-CD), and molecularly imprinted polymer-methacrylic acid, MIP(MAA); both prepared by a reversible addition fragmentation chain transfer polymerization (RAFT) in the bulk polymerization process. Both MIPs were characterized using the Fourier Transform Infrared Spectroscopy (FTIR), Field Emission Scanning Electron Microscopy (FESEM), and Brunauer-Emmett-Teller (BET). The presence of β-CD not only influenced the morphological structure, it also affected the specific surface area, average pore diameter, and total pore volume of the MIP. The rebinding of the imprinting effect was evaluated in binding experiments, which proved that the β-CD contributed significantly to the enhancement of the recognition affinity and selective adsorption of the MIP. PMID:25667978

Epigenetically regulated imprinted genes and foetal programming.

PubMed

Keverne, Eric B

2010-11-01

Genomic imprinting is a widespread epigenetic phenomenon in mammals and many imprinted genes are expressed in the developing hypothalamus and placenta. The placenta and brain are very different structures with very different roles, but in the pregnant mother they functionally interact coordinating and ensuring the provision of nutrients, timing of parturition and priming of hypothalamus for maternal care and nurturing. This interaction has been evolutionarily fine-tuned to optimise infant survival such that when resources are poor, the mother 'informs' this condition to the foetus producing a thrifty phenotype that is adapted to survive scarce resources after birth.

Imprint switch mutations at Rasgrf1 support conflict hypothesis of imprinting and define a growth control mechanism upstream of IGF1

PubMed Central

Drake, Nadia M.; Park, Yoon Jung; Shirali, Aditya S.; Cleland, Thomas A.

2010-01-01

Rasgrf1 is imprinted and expressed preferentially from the paternal allele in neonatal mouse brain. At weaning, expression becomes biallelic. Using a mouse model, we assayed the effects of perturbing imprinted Rasgrf1 expression in mice with the following imprinted expression patterns: monoallelic paternal (wild type), monoallelic maternal (maternal only), biallelic (both alleles transcribed), and null (neither allele transcribed). All genotypes exhibit biallelic expression around weaning. Consequences of this transient imprinting perturbation are manifested as overall size differences that correspond to the amount of neonatal Rasgrf1 expressed and are persistent, extending into adulthood. Biallelic mice are the largest and overexpress Rasgrf1 relative to wild-type mice, null mice are the smallest and underexpress Rasgrf1 as neonates, and the two monoallelically expressing genotypes are intermediate and indistinguishable from one another, in both size and Rasgrf1 expression level. Importantly, these data support one of the key underlying assumptions of the “conflict hypothesis” that describes the evolution of genomic imprinting in mammals and supposes that equivalent amounts of imprinted gene expression produce equivalent phenotypes, regardless of which parental allele is transcribed. Concordant with the difference in overall body size, we identify differences in IGF-1 levels, both in serum protein and as liver transcript, and identify additional differential expression of components upstream of IGF-1 release in the GH/IGF-1 axis. These data suggest that imprinted Rasgrf1 expression affects GH/IGF-1 axis function, and that the consequences of Rasgrf1 inputs to this axis persist beyond the time period when expression is restricted via epigenetic mechanisms, suggesting that proper neonatal Rasgrf1 expression levels are critical for development. PMID:19513790

Preparation and recognition performance of creatinine-imprinted material prepared with novel surface-imprinting technique.

PubMed

Gao, Baojiao; Li, Yanbin; Zhang, Zhenguo

2010-08-01

By adopting the novel surface molecular imprinting technique put forward by us not long ago, a creatinine molecule-imprinted material with high performance was prepared. The functional macromolecule polymethacrylic acid (PMAA) was first grafted on the surfaces of micron-sized silica gel particles in the manner of "grafting from" using 3-methacryloxypropyltrimethoxysilane (MPS) as intermedia, resulting in the grafted particles PMAA/SiO(2). Subsequently, the molecular imprinting was carried out towards the grafted macromolecule PMAA using creatinine as template and with ethylene glycol diglycidyl ether (EGGE) as crosslinker by right of the intermolecular hydrogen bonding and electrostatic interaction between the grafted PMAA and creatinine molecules. Finally, the creatinine-imprinted material MIP-PMAA/SiO(2) was obtained. The binding character of MIP-PMAA/SiO(2) for creatinine was investigated in depth with both batch and column methods and using N-hydroxysuccinimide and creatine as two contrast substances, whose chemical structures are similar to creatinine to a certain degree. The experimental results show that the surface-imprinted material MIP-PMAA/SiO(2) has excellent binding affinity and high recognition selectivity for creatinine. Before imprinting, PMAA/SiO(2) particles nearly has not recognition selectivity for creatinine, and the selectivity coefficients of PMAA/SiO(2) for creatinine relative to N-hydroxysuccinimide and creatine are only 1.23 and 1.30, respectively. However, after imprinting, the selectivity coefficients of MIP-PMAA/SiO(2) for creatinine in respect to N-hydroxysuccinimide and creatine are remarkably enhanced to 11.64 and 12.87, respectively, displaying the excellent recognition selectivity and binding affinity towards creatinine molecules. Copyright 2010 Elsevier B.V. All rights reserved.

Surface engineering: molecularly imprinted affinity membranes by photograft polymerization

NASA Astrophysics Data System (ADS)

Matuschewski, Heike; Sergeyeva, Tatiana A.; Bendig, Juergen; Piletsky, Sergey A.; Ulbricht, Matthies; Schedler, Uwe

2001-02-01

Commercial polymer microfiltration membranes were surface-modified with a graft copolymer of a functional monomer and a crosslinker in the presence of a template (triazine-herbicide). As result, membranes covered with a thin layer of imprinted polymer (MIP) selective to the template were obtained. The influence of the polymerization conditions on membrane recognition properties was studied by membranes

Surface imprinting on nano-TiO2 as sacrificial material for the preparation of hollow chlorogenic acid imprinted polymer and its recognition behavior

NASA Astrophysics Data System (ADS)

Li, Hui; Li, Gui; Li, Zhiping; Lu, Cuimei; Li, Yanan; Tan, Xianzhou

2013-01-01

Surface imprinting chlorogenic acid (CGA) on nano-TiO2 particles as sacrificial support material was successfully performed by using 4-vinylpyridine (4-VP) as functional monomer to obtain a hollow CGA-imprinted polymer (H-MIP1). Fourier transmission infrared spectrometry (FTIR) and scanning electron microscopy (SEM) were utilized for structurally characterizing the polymers obtained and adsorption dynamics and thermodynamic behavior investigated according to different models. Binding selectivity, adsorption capacity and the reusability for this H-MIP1 were also evaluated. This hollow CGA imprinted polymer shows rapid binding dynamics and higher binding capability toward the template molecules. The pseudo first-order kinetic model was shown best to describe the binding process of CGA on the H-MIP1 and Langmuir isotherm model best to fit the experimental adsorption isotherm data. Through adsorption isotherms at different temperatures, thermodynamic parameter values were obtained. Selectivity coefficients for the H-MIP1 toward the template were 2.209, 3.213, 1.746 and 2.353 relative to CA, VA, PCA and GA, respectively. This H-MIP1 was also indicated with a good imprint effect and a high capability to capture CGA from methanol extract of Eucommia ulmoides (E. ulmoides) leaves. Additionally, a good reusability for this imprinted polymer was exhibited during repeated adsorption-desorption use.

Highly selective coextraction of rhodamine B and dibenzyl phthalate based on high-density dual-template imprinted shells on silica microparticles.

PubMed

Long, Zerong; Xu, Weiwei; Peng, Yumei; Lu, Yi; Luo, Qian; Qiu, Hongdeng

2017-01-01

A simple one-pot approach based on molecularly imprinted polymer shells dispersed on the surface of silica for simultaneous determination of rhodamine B and dibenzyl phthalate (DBzP) has been developed. Highly dense molecularly imprinted polymer shells were formed in the mixture of acetonitrile and toluene by the copolymerization of methacrylic acid and ethylene glycol dimethacrylate, as well as two templates, rhodamine B and dibenzyl phthalate, directed by the vinyl end groups functional monolayer at surface silica microspheres after 3-methacryloxypropyl trimethoxysilane modification. The obtained imprinted polymer shells showed large average pore diameter (102.5 nm) and about 100 nm shell thickness. The imprinted particles also showed high imprinting factor (α RhB = 3.52 and α DBzP = 3.94), rapid binding kinetics, and excellent selective affinity capacity for rhodamine B and dibenzyl phthalate containing another three competitors in mixed solution. Moreover, the imprinted particles coupled with ultra high performance liquid chromatography was successfully applied to simultaneous analysis of rhodamine B and dibenzyl phthalate in two spiked beverage samples with average recoveries in the range of 88.0-93.0% for rhodamine B and 84.0-92.0% for dibenzyl phthalate with the relative standard deviation lower than 5.1%. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Preparation of magnetic molecularly imprinted polymers by atom transfer radical polymerization for the rapid extraction of avermectin from fish samples.

PubMed

You, Xiaoxiao; Gao, Lei; Qin, Dongli; Chen, Ligang

2017-01-01

A novel and highly efficient approach to obtain magnetic molecularly imprinted polymers is described to detect avermectin in fish samples. The magnetic molecularly imprinted polymers were synthesized by surface imprinting polymerization using magnetic multiwalled carbon nanotubes as the support materials, atom transfer radical polymerization as the polymerization method, avermectin as template, acrylamide as functional monomer, and ethylene glycol dimethacrylate as crosslinker. The characteristics of the magnetic molecularly imprinted polymers were assessed by using transmission electron microscopy, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, vibrating sample magnetometry, X-ray diffraction, and thermogravimetric analysis. The binding characteristics of magnetic molecularly imprinted polymers were researched through isothermal adsorption experiment, kinetics adsorption experiment, and the selectivity experiment. Coupled with ultra high performance liquid chromatography and tandem mass spectrometry, the extraction conditions of the magnetic molecularly imprinted polymers as adsorbents for avermectin were investigated in detail. The recovery of avermectin was 84.2-97.0%, and the limit of detection was 0.075 μg/kg. Relative standard deviations of intra- and inter-day precisions were in the range of 1.7-2.9% and 3.4-5.6%, respectively. The results demonstrated that the extraction method not only has high selectivity and accuracy, but also is convenient for the determination of avermectin in fish samples. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Synthesis of novel monomeric graphene quantum dots and corresponding nanocomposite with molecularly imprinted polymer for electrochemical detection of an anticancerous ifosfamide drug.

PubMed

Bali Prasad, Bhim; Kumar, Anil; Singh, Ragini

2017-08-15

This paper reports a typical synthesis of a nanocomposite of functionalized graphene quantum dots and imprinted polymer at the surface of screen-printed carbon electrode using N-acryloyl-4-aminobenzamide, as a functional monomer, and an anticancerous drug, ifosfamide, as a print molecule (test analyte). Herein, graphene quantum dots in nanocomposite practically induced the electrocatalytic activity by lowering the oxidation overpotential of test analyte and thereby amplifying electronic transmission, without any interfacial barrier in between the film and the electrode surface. The differential pulse anodic stripping signal at functionalized graphene quantum dots based imprinted sensor was realized to be about 3- and 7-fold higher as compared to the traditionally made imprinted polymers prepared in the presence and the absence of graphene quantum dots (un-functionalized), respectively. This may be attributed to a pertinent synergism in between the positively charged functionalized graphene quantum dots in the film and the target analyte toward the enhancement of electro-conductivity of the film and thereby the electrode kinetics. In fact, the covalent attachment of graphene quantum dots with N-acryloyl-4-aminobenzamide molecules might exert an extended conjugation at their interface facilitating electro conducting to render the channelized pathways for the electron transport. The proposed sensor is practically applicable to the ultratrace evaluation of ifosfamide in real (biological/pharmaceutical) samples with detection limit as low as 0.11ngmL -1 (S/N=3), without any matrix effect, cross-reactivity, and false-positives. Copyright © 2017 Elsevier B.V. All rights reserved.

Producing superfluid circulation states using phase imprinting

NASA Astrophysics Data System (ADS)

Kumar, Avinash; Dubessy, Romain; Badr, Thomas; De Rossi, Camilla; de Goër de Herve, Mathieu; Longchambon, Laurent; Perrin, Hélène

2018-04-01

We propose a method to prepare states of given quantized circulation in annular Bose-Einstein condensates (BEC) confined in a ring trap using the method of phase imprinting without relying on a two-photon angular momentum transfer. The desired phase profile is imprinted on the atomic wave function using a short light pulse with a tailored intensity pattern generated with a spatial light modulator. We demonstrate the realization of "helicoidal" intensity profiles suitable for this purpose. Due to the diffraction limit, the theoretical steplike intensity profile is not achievable in practice. We investigate the effect of imprinting an intensity profile smoothed by a finite optical resolution onto the annular BEC with a numerical simulation of the time-dependent Gross-Pitaevskii equation. This allows us to optimize the intensity pattern for a given target circulation to compensate for the limited resolution.

Towards developing an efficient sensitive element for trinitrotoluene detection: TiO2 thin films functionalized with molecularly imprinted copolymer films

NASA Astrophysics Data System (ADS)

Lazau, Carmen; Iordache, Tanta-Verona; Florea, Ana-Mihaela; Orha, Corina; Bandas, Cornelia; Radu, Anita-Laura; Sarbu, Andrei; Rotariu, Traian

2016-10-01

In this study, TiO2 films were successfully grown in-situ onto a FTO substrate by a hydrothermal method, using TiCl4 as Ti precursor, and further on functionalized with a 2,4,6-trinitrotoluene-molecularly imprinted polymer (TNT-MIP) film as a preliminary step in developing a trinitrotoluene (TNT) reusable sensor to overcome the international security issues. For investigating the TiO2 film thickness, crystalline structure and morphology, the films were autoclaved at 200 °C at different times. The X-ray diffraction showed that TiO2 films possessed a rutile structure, with no cracks visible by atomic force microscopy (AFM), and the films morphology observed by scanning electron microscopy (SEM) was highly dependent upon the hydrothermal treatment time. Yet, the TiO2 films with a more porous surface were more suitable for TNT-MIP film deposit. Rheology of precursor polymer film solutions, based on poly (acrylonitrile-co-acrylic acid), poly (acrylonitrile-co-methacrylic acid) or poly (acrylonitrile- co-itaconic acid), and the structure and adherence of TNT-MIP films were investigated in order to establish the correct recipe of the MIP. The removal yield of TNT from the imprinted films, the thickness, the porosity and the compatibility with the inorganic TiO2 film were adequate for the poly (acrylonitrile-co-acrylic acid) system with an acrylonitrile: acrylic acid practical ratio of 86.1:13.9 (wt./wt.). Farmore, AFM morphology corroborated with SEM results highlighted the effect of TNT imprinting in the copolymer matrix as the surface of the imprinted layer was quite different from that of the non-imprinted layer.

Retrotransposed genes such as Frat3 in the mouse Chromosome 7C Prader-Willi syndrome region acquire the imprinted status of their insertion site.

PubMed

Chai, J H; Locke, D P; Ohta, T; Greally, J M; Nicholls, R D

2001-11-01

Prader-Willi syndrome (PWS) results from loss of function of a 1.0- to 1.5-Mb domain of imprinted, paternally expressed genes in human Chromosome (Chr) 15q11-q13. The loss of imprinted gene expression in the homologous region in mouse Chr 7C leads to a similar neonatal PWS phenotype. Several protein-coding genes in the human PWS region are intronless, possibly arising by retrotransposition. Here we present evidence for continued acquisition of genes by the mouse PWS region during evolution. Bioinformatic analyses identified a BAC containing four genes, Mkrn3, Magel2, Ndn, Frat3, and the Atp5l-ps1 pseudogene, the latter two genes derived from recent L1-mediated retrotransposition. Analyses of eight overlapping BACs indicate that these genes are clustered within 120 kb in two inbred strains, in the order tel-Atp5l-ps1-Frat3-Mkrn3-Magel2-Ndn-cen. Imprinting analyses show that Frat3 is differentially methylated and expressed solely from the paternal allele in a transgenic mouse model of Angelman syndrome, with no expression from the maternal allele in a mouse model of PWS. Loss of Frat3 expression may, therefore, contribute to the phenotype of mouse models of PWS. The identification of five intronless genes in a small genomic interval suggests that this region is prone to retroposition in germ cells or their zygotic and embryonic cell precursors, and that it allows the subsequent functional expression of these foreign sequences. The recent evolutionary acquisition of genes that adopt the same imprint as older, flanking genes indicates that the newly acquired genes become 'innocent bystanders' of a primary epigenetic signal causing imprinting in the PWS domain.

Deregulation of an imprinted gene network in prostate cancer

PubMed Central

Ribarska, Teodora; Goering, Wolfgang; Droop, Johanna; Bastian, Klaus-Marius; Ingenwerth, Marc; Schulz, Wolfgang A

2014-01-01

Multiple epigenetic alterations contribute to prostate cancer progression by deregulating gene expression. Epigenetic mechanisms, especially differential DNA methylation at imprinting control regions (termed DMRs), normally ensure the exclusive expression of imprinted genes from one specific parental allele. We therefore wondered to which extent imprinted genes become deregulated in prostate cancer and, if so, whether deregulation is due to altered DNA methylation at DMRs. Therefore, we selected presumptive deregulated imprinted genes from a previously conducted in silico analysis and from the literature and analyzed their expression in prostate cancer tissues by qRT-PCR. We found significantly diminished expression of PLAGL1/ZAC1, MEG3, NDN, CDKN1C, IGF2, and H19, while LIT1 was significantly overexpressed. The PPP1R9A gene, which is imprinted in selected tissues only, was strongly overexpressed, but was expressed biallelically in benign and cancerous prostatic tissues. Expression of many of these genes was strongly correlated, suggesting co-regulation, as in an imprinted gene network (IGN) reported in mice. Deregulation of the network genes also correlated with EZH2 and HOXC6 overexpression. Pyrosequencing analysis of all relevant DMRs revealed generally stable DNA methylation between benign and cancerous prostatic tissues, but frequent hypo- and hyper-methylation was observed at the H19 DMR in both benign and cancerous tissues. Re-expression of the ZAC1 transcription factor induced H19, CDKN1C and IGF2, supporting its function as a nodal regulator of the IGN. Our results indicate that a group of imprinted genes are coordinately deregulated in prostate cancers, independently of DNA methylation changes. PMID:24513574

Deregulation of an imprinted gene network in prostate cancer.

PubMed

Ribarska, Teodora; Goering, Wolfgang; Droop, Johanna; Bastian, Klaus-Marius; Ingenwerth, Marc; Schulz, Wolfgang A

2014-05-01

Multiple epigenetic alterations contribute to prostate cancer progression by deregulating gene expression. Epigenetic mechanisms, especially differential DNA methylation at imprinting control regions (termed DMRs), normally ensure the exclusive expression of imprinted genes from one specific parental allele. We therefore wondered to which extent imprinted genes become deregulated in prostate cancer and, if so, whether deregulation is due to altered DNA methylation at DMRs. Therefore, we selected presumptive deregulated imprinted genes from a previously conducted in silico analysis and from the literature and analyzed their expression in prostate cancer tissues by qRT-PCR. We found significantly diminished expression of PLAGL1/ZAC1, MEG3, NDN, CDKN1C, IGF2, and H19, while LIT1 was significantly overexpressed. The PPP1R9A gene, which is imprinted in selected tissues only, was strongly overexpressed, but was expressed biallelically in benign and cancerous prostatic tissues. Expression of many of these genes was strongly correlated, suggesting co-regulation, as in an imprinted gene network (IGN) reported in mice. Deregulation of the network genes also correlated with EZH2 and HOXC6 overexpression. Pyrosequencing analysis of all relevant DMRs revealed generally stable DNA methylation between benign and cancerous prostatic tissues, but frequent hypo- and hyper-methylation was observed at the H19 DMR in both benign and cancerous tissues. Re-expression of the ZAC1 transcription factor induced H19, CDKN1C and IGF2, supporting its function as a nodal regulator of the IGN. Our results indicate that a group of imprinted genes are coordinately deregulated in prostate cancers, independently of DNA methylation changes.

Theoretical investigation on functional monomer and solvent selection for molecular imprinting of tramadol

NASA Astrophysics Data System (ADS)

Fonseca, Matheus C.; Nascimento, Clebio S.; Borges, Keyller B.

2016-02-01

The purpose of this Letter was to study for the first time the interaction process of tramadol (TRM) with distinct functional monomers (FM) in the formation of molecular imprinted polymer (MIP), using density functional theory (DFT) calculations at B3LYP/6-31G(d,p). As result we were able to establish that the best MIP synthesis conditions are obtained with acrylic acid as FM in 1:3 molar ratio and with chloroform as solvent. This condition presented the lowest stabilization energy for the pre-polymerization complexes. Besides, the intermolecular hydrogen bonds found between the template molecule and functional monomers play a primary role to the complex stability.

Characterization of QCM sensor surfaces coated with molecularly imprinted nanoparticles.

PubMed

Reimhult, Kristina; Yoshimatsu, Keiichi; Risveden, Klas; Chen, Si; Ye, Lei; Krozer, Anatol

2008-07-15

Molecularly imprinted polymers (MIPs) are gaining great interest as tailor-made recognition materials for the development of biomimetic sensors. Various approaches have been adopted to interface MIPs with different transducers, including the use of pre-made imprinted particles and the in situ preparation of thin polymer layers directly on transducer surfaces. In this work we functionalized quartz crystal microbalance (QCM) sensor crystals by coating the sensing surfaces with pre-made molecularly imprinted nanoparticles. The nanoparticles were immobilized on the QCM transducers by physical entrapment in a thin poly(ethylene terephthalate) (PET) layer that was spin-coated on the transducer surface. By controlling the deposition conditions, it was possible to gain a high nanoparticle loading in a stable PET layer, allowing the recognition sites in nanoparticles to be easily accessed by the test analytes. In this work, different sensor surfaces were studied by micro-profilometry and atomic force microscopy and the functionality was evaluated using quartz crystal microbalance with dissipation (QCM-D). The molecular recognition capability of the sensors were also confirmed using radioligand binding analysis by testing their response to the presence of the test compounds, (R)- and (S)-propranolol in aqueous buffer.

A study of the influence of different genotypes on the physical and behavioral phenotypes of children and adults ascertained clinically as having PWS.

PubMed

Webb, T; Whittington, J; Clarke, D; Boer, H; Butler, J; Holland, A

2002-10-01

A population-based cohort of people with a clinical diagnosis of Prader-Willi syndrome (PWS) was genetically assessed using molecular diagnostic methods and subsequently divided into the following genetic subtypes involving chromosome 15: 'deletion', 'disomy' and genetically negative (referred to as 'PWS-like'). The physical and behavioral characteristics of the three groups were compared in order to evaluate the unique characteristics of the phenotype resulting from loss of expression of imprinted genes at 15q11q13 (PWS vs. PWS-like cases), the possible effect of either haploid insufficiency of non-imprinted genes (deletion cases), or gain of function of imprinted genes (disomy cases) located within the PWS critical region at 15q11q13. In this study, the main differences between probands with either a deletion or disomy are considered, and the possible involvement of contributing genes discussed. The differences within the PWS group proved difficult to quantify. It would appear that haploid insufficiency or gain of function are more subtle contributors than gender-specific genomic imprinting in the production of the PWS phenotype.

Chiral determination of cinchonine using an electrochemiluminescent sensor with molecularly imprinted membrane on the surfaces of magnetic particles.

PubMed

Yuan, Xingyi; Tan, Yanji; Wei, Xiaoping; Li, Jianping

2017-11-01

A novel molecular imprinting electrochemiluminescence sensor for detecting chiral cinchonine molecules was developed with a molecularly imprinted polymer membrane on the surfaces of magnetic microspheres. Fe 3 O 4 @Au nanoparticles modified with 6-mercapto-beta-cyclodextrin were used as a carrier, cinchonine as a template molecule, methacrylic acid as a functional monomer and N,N'-methylenebisacrylamide as a cross-linking agent. Cinchonine was specifically recognized by the 6-mercapto-beta-cyclodextrin functional molecularly imprinted polymer and detected based on enhancement of the electrochemiluminescence intensity caused by the reaction of tertiary amino structures of cinchonine molecules with Ru(bpy) 3 2+ . Cinchonine concentrations of 1 × 10 -10 to 4 × 10 -7  mol/L showed a good linear relationship with changes of the electrochemiluminescence intensity, and the detection limit of the sensor was 3.13 × 10 -11  mol/L. The sensor has high sensitivity and selectivity, and is easy to renew. It was designed for detecting serum samples, with recovery rates of 98.2% to 107.6%. Copyright © 2017 John Wiley & Sons, Ltd.

Aflatoxin B1 Detection Using a Highly-Sensitive Molecularly-Imprinted Electrochemical Sensor Based on an Electropolymerized Metal Organic Framework

PubMed Central

Jiang, Mengjuan; Braiek, Mohamed; Florea, Anca; Chrouda, Amani; Farre, Carole; Bonhomme, Anne; Bessueille, Francois; Vocanson, Francis; Zhang, Aidong; Jaffrezic-Renault, Nicole

2015-01-01

A sensitive electrochemical molecularly-imprinted sensor was developed for the detection of aflatoxin B1 (AFB1), by electropolymerization of p-aminothiophenol-functionalized gold nanoparticles in the presence of AFB1 as a template molecule. The extraction of the template leads to the formation of cavities that are able to specifically recognize and bind AFB1 through π-π interactions between AFB1 molecules and aniline moities. The performance of the developed sensor for the detection of AFB1 was investigated by linear sweep voltammetry using a hexacyanoferrate/hexacyanoferrite solution as a redox probe, the electron transfer rate increasing when the concentration of AFB1 increases, due to a p-doping effect. The molecularly-imprinted sensor exhibits a broad linear range, between 3.2 fM and 3.2 µM, and a quantification limit of 3 fM. Compared to the non-imprinted sensor, the imprinting factor was found to be 10. Selectivity studies were also performed towards the binding of other aflatoxins and ochratoxin A, proving good selectivity. PMID:26371042

Preparation of diclofenac-imprinted polymer beads for selective molecular separation in water.

PubMed

Zhou, Tongchang; Kamra, Tripta; Ye, Lei

2018-03-01

Molecular imprinting technique is an attractive strategy to prepare materials for target recognition and rapid separation. In this work, a new type of diclofenac (DFC)-imprinted polymer beads was synthesized by Pickering emulsion polymerization using 2-(dimethylamino)ethyl methacrylate as the functional monomer. The selectivity and capacity of the molecularly imprinted polymers (MIPs) were investigated in aqueous solution. Equilibrium binding results show that the MIPs have a high selectivity to bind DFC in a wide range of pH values. Moreover, in liquid chromatography experiment, the imprinted polymer beads were packed into column to investigate the binding selectivity under nonequilibrium conditions. The retention time of DFC on the MIP column is significantly longer than its structural analogues. Also, retention of DFC on the MIP column was significantly longer than on the nonimprinted polymer column under aqueous condition. As the new MIP beads can be used to achieve direct separation of DFC from water, the synthetic method and the affinity beads developed in this work opened new possibilities for removing toxic chemicals from environmental and drinking water. Copyright © 2017 John Wiley & Sons, Ltd.

The Drosophila melanogaster homolog of UBE3A is not imprinted in neurons.

PubMed

Hope, Kevin A; LeDoux, Mark S; Reiter, Lawrence T

2016-09-01

In mammals, expression of UBE3A is epigenetically regulated in neurons and expression is restricted to the maternal copy of UBE3A. A recent report claimed that Drosophila melanogaster UBE3A homolog (Dube3a) is preferentially expressed from the maternal allele in fly brain, inferring an imprinting mechanism. However, complex epigenetic regulatory features of the mammalian imprinting center are not present in Drosophila, and allele specific expression of Dube3a has not been documented. We used behavioral and electrophysiological analysis of the Dube3a loss-of-function allele (Dube3a 15b ) to investigate Dube3a imprinting in fly neurons. We found that motor impairment (climbing ability) and a newly-characterized defect in synaptic transmission are independent of parental inheritance of the Dube3a 15b allele. Furthermore, expression analysis of coding single nucleotide polymorphisms (SNPs) in Dube3a did not reveal allele specific expression differences among reciprocal crosses. These data indicate that Dube3a is neither imprinted nor preferentially expressed from the maternal allele in fly neurons.

Photoresponsive surface molecularly imprinted polymer on ZnO nanorods for uric acid detection in physiological fluids.

PubMed

Tang, Qian; Li, Zai-Yong; Wei, Yu-Bo; Yang, Xia; Liu, Lan-Tao; Gong, Cheng-Bin; Ma, Xue-Bing; Lam, Michael Hon-Wah; Chow, Cheuk-Fai

2016-09-01

A photoresponsive surface molecularly imprinted polymer for uric acid in physiological fluids was fabricated through a facile and effective method using bio-safe and biocompatible ZnO nanorods as a support. The strategy was carried out by introducing double bonds on the surface of the ZnO nanorods with 3-methacryloxypropyltrimethoxysilane. The surface molecularly imprinted polymer on ZnO nanorods was then prepared by surface polymerization using uric acid as template, water-soluble 5-[(4-(methacryloyloxy)phenyl)diazenyl]isophthalic acid as functional monomer, and triethanolamine trimethacryl ester as cross-linker. The surface molecularly imprinted polymer on ZnO nanorods showed good photoresponsive properties, high recognition ability, and fast binding kinetics toward uric acid, with a dissociation constant of 3.22×10(-5)M in aqueous NaH2PO4 buffer at pH=7.0 and a maximal adsorption capacity of 1.45μmolg(-1). Upon alternate irradiation at 365 and 440nm, the surface molecularly imprinted polymer on ZnO nanorods can quantitatively uptake and release uric acid. Copyright © 2016 Elsevier B.V. All rights reserved.

Campanile Near-Field Probes Fabricated by Nanoimprint Lithography on the Facet of an Optical Fiber

DOE PAGES

Calafiore, Giuseppe; Koshelev, Alexander; Darlington, Thomas P.; ...

2017-05-10

One of the major challenges to the widespread adoption of plasmonic and nano-optical devices in real-life applications is the difficulty to mass-fabricate nano-optical antennas in parallel and reproducible fashion, and the capability to precisely place nanoantennas into devices with nanometer-scale precision. In this study, we present a solution to this challenge using the state-of-the-art ultraviolet nanoimprint lithography (UV-NIL) to fabricate functional optical transformers onto the core of an optical fiber in a single step, mimicking the 'campanile' near-field probes. Imprinted probes were fabricated using a custom-built imprinter tool with co-axial alignment capability with sub < 100 nm position accuracy, followedmore » by a metallization step. Scanning electron micrographs confirm high imprint fidelity and precision with a thin residual layer to facilitate efficient optical coupling between the fiber and the imprinted optical transformer. The imprinted optical transformer probe was used in an actual NSOM measurement performing hyperspectral photoluminescence mapping of standard fluorescent beads. The calibration scans confirmed that imprinted probes enable sub-diffraction limited imaging with a spatial resolution consistent with the gap size. This novel nano-fabrication approach promises a low-cost, high-throughput, and reproducible manufacturing of advanced nano-optical devices.« less

Campanile Near-Field Probes Fabricated by Nanoimprint Lithography on the Facet of an Optical Fiber

DOE Office of Scientific and Technical Information (OSTI.GOV)

Calafiore, Giuseppe; Koshelev, Alexander; Darlington, Thomas P.

One of the major challenges to the widespread adoption of plasmonic and nano-optical devices in real-life applications is the difficulty to mass-fabricate nano-optical antennas in parallel and reproducible fashion, and the capability to precisely place nanoantennas into devices with nanometer-scale precision. In this study, we present a solution to this challenge using the state-of-the-art ultraviolet nanoimprint lithography (UV-NIL) to fabricate functional optical transformers onto the core of an optical fiber in a single step, mimicking the 'campanile' near-field probes. Imprinted probes were fabricated using a custom-built imprinter tool with co-axial alignment capability with sub < 100 nm position accuracy, followedmore » by a metallization step. Scanning electron micrographs confirm high imprint fidelity and precision with a thin residual layer to facilitate efficient optical coupling between the fiber and the imprinted optical transformer. The imprinted optical transformer probe was used in an actual NSOM measurement performing hyperspectral photoluminescence mapping of standard fluorescent beads. The calibration scans confirmed that imprinted probes enable sub-diffraction limited imaging with a spatial resolution consistent with the gap size. This novel nano-fabrication approach promises a low-cost, high-throughput, and reproducible manufacturing of advanced nano-optical devices.« less

Innovative Design and Performance Evaluation of Bionic Imprinting Toothed Wheel

PubMed Central

Wang, Xiaoyang; Tong, Jin; Stephen, Carr

2018-01-01

A highly efficient soil-burrowing dung beetle possesses an intricate outer contour curve on its foreleg end-tooth. This study was carried out based on evidence that this special outer contour curve has the potential of reducing soil penetration resistance and could enhance soil-burrowing efficiency. A toothed wheel is a typical agricultural implement for soil imprinting, to increase its working efficiency; the approach of the bionic geometrical structure was utilized to optimize the innovative shape of imprinting toothed wheel. Characteristics in the dung beetle's foreleg end-tooth were extracted and studied by the edge detection technique. Then, this special outer contour curve was modeled by a nine-order polynomial function and used for the innovative design of imprinting the tooth's cutting edge. Both the conventional and bionic teeth were manufactured, and traction tests in a soil bin were conducted. Taking required draft force and volume of imprinted microbasin as the evaluating indexes, operating efficiency and quality of different toothed wheels were compared and investigated. Results indicate that compared with the conventional toothed wheel, a bionic toothed wheel possesses a better forward resistance reduction property against soil and, meanwhile, can enhance the quality of soil imprinting by increasing the volume of the created micro-basin. PMID:29515651

Induced Pluripotent Stem Cells Can Be Used to Model the Genomic Imprinting Disorder Prader-Willi Syndrome*

PubMed Central

Yang, Jiayin; Cai, Jie; Zhang, Ya; Wang, Xianming; Li, Wen; Xu, Jianyong; Li, Feng; Guo, Xiangpeng; Deng, Kang; Zhong, Mei; Chen, Yonglong; Lai, Liangxue; Pei, Duanqing; Esteban, Miguel A.

2010-01-01

The recent discovery of induced pluripotent stem cell (iPSC) technology provides an invaluable tool for creating in vitro representations of human genetic conditions. This is particularly relevant for those diseases that lack adequate animal models or where the species comparison is difficult, e.g. imprinting diseases such as the neurogenetic disorder Prader-Willi syndrome (PWS). However, recent reports have unveiled transcriptional and functional differences between iPSCs and embryonic stem cells that in cases are attributable to imprinting errors. This has suggested that human iPSCs may not be useful to model genetic imprinting diseases. Here, we describe the generation of iPSCs from a patient with PWS bearing a partial translocation of the paternally expressed chromosome 15q11-q13 region to chromosome 4. The resulting iPSCs match all standard criteria of bona fide reprogramming and could be readily differentiated into tissues derived from the three germ layers, including neurons. Moreover, these iPSCs retain a high level of DNA methylation in the imprinting center of the maternal allele and show concomitant reduced expression of the disease-associated small nucleolar RNA HBII-85/SNORD116. These results indicate that iPSCs may be a useful tool to study PWS and perhaps other genetic imprinting diseases as well. PMID:20956530

Molecularly imprinted polymer sensors for detection in the gas, liquid, and vapor phase.

PubMed

Jenkins, Amanda L; Ellzy, Michael W; Buettner, Leonard C

2012-06-01

Fast, reliable, and inexpensive analytical techniques for detection of airborne chemical warfare agents are desperately needed. Recent advances in the field of molecularly imprinted polymers have created synthetic nanomaterials that can sensitively and selectively detect these materials in aqueous environments, but thus far, they have not been demonstrated to work for detection of vapors. The imprinted polymers function by mimicking the function of biological receptors. They can provide high sensitivity and selectivity but, unlike their biological counterparts, maintain excellent thermal and mechanical stability. The traditional imprinted polymer approach is further enhanced in this work by the addition of a luminescent europium that has been introduced into the polymers to provide enhanced chemical affinity as well as a method for signal transduction to indicate the binding event. The europium in these polymers is so sensitive to the bound target; it can distinguish between species differing by a single methyl group. The imprinted polymer technology is fiber optic-based making it inexpensive and easily integratable with commercially available miniature fiber optic spectrometer technologies to provide a shoebox size device. In this work, we will describe efforts to apply these sensors for detection of airborne materials and vapors. Successful application of this technology will provide accurate low level vapor detection of chemical agents or pesticides with little to no false positives. Published 2012. This article is a U.S. Government work and is in the public domain in the USA.

A new deletion refines the boundaries of the murine Prader–Willi syndrome imprinting center

PubMed Central

DuBose, Amanda J.; Smith, Emily Y.; Yang, Thomas P.; Johnstone, Karen A.; Resnick, James L.

2011-01-01

The human chromosomal 15q11–15q13 region is subject to both maternal and paternal genomic imprinting. Absence of paternal gene expression from this region results in Prader–Willi syndrome (PWS), while absence of maternal gene expression leads to Angelman syndrome. Transcription of paternally expressed genes in the region depends upon an imprinting center termed the PWS-IC. Imprinting defects in PWS can be caused by microdeletions and the smallest commonly deleted region indicates that the PWS-IC lies within a region of 4.3 kb. The function and location of the PWS-IC is evolutionarily conserved, but delineation of the PWS-IC in mouse has proven difficult. The first targeted mutation of the PWS-IC, a deletion of 35 kb spanning Snrpn exon 1, exhibited a complete PWS-IC deletion phenotype. Pups inheriting this mutation paternally showed a complete loss of paternal gene expression and died neonatally. A reported deletion of 4.8 kb showed only a reduction in paternal gene expression and incomplete penetrance of neonatal lethality, suggesting that some PWS-IC function had been retained. Here, we report that a 6 kb deletion spanning Snrpn exon 1 exhibits a complete PWS-IC deletion phenotype. Pups inheriting this mutation paternally lack detectable expression of all PWS genes and paternal silencing of Ube3a, exhibit maternal DNA methylation imprints at Ndn and Mkrn3 and suffer failure to thrive leading to a fully penetrant neonatal lethality. PMID:21659337

A new deletion refines the boundaries of the murine Prader-Willi syndrome imprinting center.

PubMed

Dubose, Amanda J; Smith, Emily Y; Yang, Thomas P; Johnstone, Karen A; Resnick, James L

2011-09-01

The human chromosomal 15q11-15q13 region is subject to both maternal and paternal genomic imprinting. Absence of paternal gene expression from this region results in Prader-Willi syndrome (PWS), while absence of maternal gene expression leads to Angelman syndrome. Transcription of paternally expressed genes in the region depends upon an imprinting center termed the PWS-IC. Imprinting defects in PWS can be caused by microdeletions and the smallest commonly deleted region indicates that the PWS-IC lies within a region of 4.3 kb. The function and location of the PWS-IC is evolutionarily conserved, but delineation of the PWS-IC in mouse has proven difficult. The first targeted mutation of the PWS-IC, a deletion of 35 kb spanning Snrpn exon 1, exhibited a complete PWS-IC deletion phenotype. Pups inheriting this mutation paternally showed a complete loss of paternal gene expression and died neonatally. A reported deletion of 4.8 kb showed only a reduction in paternal gene expression and incomplete penetrance of neonatal lethality, suggesting that some PWS-IC function had been retained. Here, we report that a 6 kb deletion spanning Snrpn exon 1 exhibits a complete PWS-IC deletion phenotype. Pups inheriting this mutation paternally lack detectable expression of all PWS genes and paternal silencing of Ube3a, exhibit maternal DNA methylation imprints at Ndn and Mkrn3 and suffer failure to thrive leading to a fully penetrant neonatal lethality.

Controlled release of mitomycin C from PHEMAH-Cu(II) cryogel membranes.

PubMed

Bakhshpour, Monireh; Yavuz, Handan; Denizli, Adil

2018-02-19

Molecular imprinting technique was used for the preparation of antibiotic and anti-neoplastic chemotherapy drug (mitomycin C) imprinted cryogel membranes (MMC-ICM). The membranes were synthezied by using metal ion coordination interactions with N-methacryloyl-(l)-histidine methyl ester (MAH) functional monomer and template molecules (i.e. MMC). The 2-hydroxyethyl methacrylate (HEMA) monomer and methylene bisacrylamide (MBAAm) crosslinker were used for the preparation of mitomycin C imprinted cryogel membranes by radical suspension polymerization technique. The imprinted cryogel membranes were characterized by scanning electron microscopy (SEM), Brunauer-Emmett-Teller (BET), Fourier transform infrared spectroscopy-attenuated total reflectance (FTIR-ATR) and swelling degree measurements. Cytotoxicity of MMC-ICMs was investigated using mouse fibroblast cell line L929. Time-dependent release of MMC was demonstrated within 150 h from cryogel membranes. Cryogels demonstrated very high MMC loading efficiency (70-80%) and sustained MMC release over hours.

Experimental mixture design as a tool for the synthesis of antimicrobial selective molecularly imprinted monodisperse microbeads.

PubMed

Benito-Peña, Elena; Navarro-Villoslada, Fernando; Carrasco, Sergio; Jockusch, Steffen; Ottaviani, M Francesca; Moreno-Bondi, Maria C

2015-05-27

The effect of the cross-linker on the shape and size of molecular imprinted polymer (MIP) beads prepared by precipitation polymerization has been evaluated using a chemometric approach. Molecularly imprinted microspheres for the selective recognition of fluoroquinolone antimicrobials were prepared in a one-step precipitation polymerization procedure using enrofloxacin (ENR) as the template molecule, methacrylic acid as functional monomer, 2-hydroxyethyl methacrylate as hydrophilic comonomer, and acetonitrile as the porogen. The type and amount of cross-linker, namely ethylene glycol dimethacrylate, divinylbenzene or trimethylolpropane trimethacrylate, to obtain monodispersed MIP spherical beads in the micrometer range was optimized using a simplex lattice design. Particle size and morphology were assessed by scanning electron microscopy, dynamic light scattering, and nitrogen adsorption measurements. Electron paramagnetic resonance spectroscopy in conjunction with a nitroxide as spin probe revealed information about the microviscosity and polarity of the binding sites in imprinted and nonimprinted polymer beads.

[Preparation and evaluation of novel mesoporous molecular sieve of baicalin surface molecularly imprinted polymers].

PubMed

Gu, Xia-li; He, Hong-liang; Shi, Li-ying; Gao, Yan-kun; Chen, Li-na

2015-05-01

Taking mesoporous molecular sieve MCM-41 as a substrate, baicalin (BA) as template, acrylamide (AM) as the functional monomer, ethylene glycol dimethacrylate (EGDMA) as a cross-linking agent, ethanol as solvent, under thermal polymerization initiator of azobis isobutyronitrilo (AIBN) , a kind of selective recognition of baicalin surface molecularly imprinted polymer was synthesized. The surface morphologies and characteristics of the MIPs were characterized by infrared spectroscopy (IR) and transmission electron microscope (TEM). The adsorption properties of polymer microsphere for the template were tested by the dynamic adsorption equilibrium experiments and static adsorption equilibrium experiments. The experiment showed that the imprinting process was successfully and the well-ordered one-dimensional pore structure of MCM-41 was still preserved. Furthermore, molecularly imprinted polymers had higher selective ability for BA, then provided a new method for the efficient separation and enrichment of baicalin active ingredients from medicinal plants Scutellaria baicalensis.

Development of ocular drug delivery systems using molecularly imprinted soft contact lenses.

PubMed

Tashakori-Sabzevar, Faezeh; Mohajeri, Seyed Ahmad

2015-05-01

Recently, significant advances have been made in order to optimize drug delivery to ocular tissues. The main problems in ocular drug delivery are poor bioavailability and uncontrollable drug delivery of conventional ophthalmic preparations (e.g. eye drops). Hydrogels have been investigated since 1965 as new ocular drug delivery systems. Increase of hydrogel loading capacity, optimization of drug residence time on the ocular surface and biocompatibility with the eye tissue has been the main focus of previous studies. Molecular imprinting technology provided the opportunity to fulfill the above-mentioned objectives. Molecularly imprinted soft contact lenses (SCLs) have high potentials as novel drug delivery systems for the treatment of eye disorders. This technique is used for the preparation of polymers with specific binding sites for a template molecule. Previous studies indicated that molecular imprinting technology could be successfully applied for the preparation of SCLs as ocular drug delivery systems. Previous research, particularly in vivo studies, demonstrated that molecular imprinting is a versatile and effective method in optimizing the drug release behavior and enhancing the loading capacity of SCLs as new ocular drug delivery systems. This review highlights various potentials of molecularly imprinted contact lenses in enhancing the drug-loading capacity and controlling the drug release, compared to other ocular drug delivery systems. We have also studied the effects of contributing factors such as the type of comonomer, template/functional monomer molar ratio, crosslinker concentration in drug-loading capacity, and the release properties of molecularly imprinted hydrogels.

Gene expression of Dio2 (thyroid hormone converting enzyme) in telencephalon is linked with predisposed biological motion preference in domestic chicks.

PubMed

Takemura, Yuri; Yamaguchi, Shinji; Aoki, Naoya; Miura, Momoko; Homma, Koichi J; Matsushima, Toshiya

2018-04-25

Filial imprinting leads to the formation of social attachment if training is performed during a brief sensitive period after hatching. We found that thyroid hormone (3,5,3'-triiodothyronine, T3) acts as a critical determining factor of the sensitive period in domestic chicks. Imprinting upregulates gene expression of the converting enzyme (Dio2, type 2 iodothyronine deiodinase) in the telencephalon, leading to increased brain T3 content. If systemically applied, T3 facilitates imprinting in aged chicks even after the sensitive period is over. Imprinting is also associated with the rapid development of visual perception. Exposure to motion pictures induces a predisposed preference to Johansson's biological motion (BM), and those individuals with higher BM preference are more easily imprinted. Here, we examined whether Dio2 expression is also linked with BM predisposition. Chicks were trained by a rotating red block, and tested for imprinting (experiment 1) and BM preference (experiment 2). To examine the time courses of behavioural and physiological processes, Dio2 expression in telencephalon was compared among three groups: naïve control chicks, and chicks trained for a short (0.5 h) or long period (2 h). In experiment 1, higher Dio2 expression appeared in the 2-h group than in the 0.5-h/control groups, but it was not correlated with the individual imprinting score. In experiment 2, a significant positive correlation appeared between Dio2 expression and BM preference in 2-h-trained chicks. Memory priming by T3 is therefore functionally linked to BM preference induction, leading to successful imprinting to natural objects even when they are initially exposed to artificial objects. Copyright © 2018 Elsevier B.V. All rights reserved.

Chromium(III)-imprinted silica gel for speciation analysis of chromium in environmental water samples with ICP-MS detection.

PubMed

Zhang, Nan; Suleiman, Jibrin Sabo; He, Man; Hu, Bin

2008-04-15

A new chromium(III)-imprinted 3-(2-aminoethylamino) propyltrimethoxysilane (AAPTS)-functionalized silica gel sorbent was synthesized by a surface imprinting technique and was employed as a selective solid-phase extraction material for speciation analysis of chromium in environmental water samples prior to its determination by inductively coupled plasma mass spectrometry (ICP-MS). The prepared Cr(III)-imprinted silica gel shows the selectivity coefficient of more than 700 for Cr(III) in the presence of Mn(II). The static adsorption capacity of the ion-imprinted and non-imprinted sorbent for Cr(III) were 30.5 mg g(-1) and 13.4 mg g(-1). It was also found that Cr(VI) could be adsorbed at low pH by the prepared imprinted silica gel, and this finding makes it feasible to enrich and determine Cr(VI) at low pH without adding reducing reagents. The imprinted silica gel sorbent offered a fast kinetics for the adsorption and desorption of both chromium species. Under the optimized conditions, the detection limits of 4.43 pg mL(-1) and 8.30 pg mL(-1) with the relative standard deviations (R.S.D.s) of 4.44% and 4.41% (C=0.5 ng mL(-1), n=7) for Cr(III) and Cr(VI) were obtained, respectively. The proposed method was successfully applied to the speciation of trace chromium in environmental water samples. To validate the proposed method, two certified reference materials were analyzed and the determined values were in a good agreement with the certified values. The developed method is rapid, selective, sensitive and applicable for the speciation of trace chromium in environmental water samples.

Synthesis and application of selective adsorbent for pirimicarb pesticides in aqueous media using allyl-β-cyclodextrin based binary functional monomers.

PubMed

He, Chengzijing; Lay, Sovichea; Yu, Haining; Shen, Shengrong

2018-04-01

Binary functional monomers, allyl-β-cyclodextrin (allyl-β-CD) and methacrylic acid (MAA) or allyl-β-CD and acrylonitrile (AN), were exploited in a fabrication of molecularly imprinted polymers (MIPs) for selective recognition and large enrichment of pirimicarb from aqueous media. Special attention was paid to the computational simulation of the imprinting molecular and functional monomers. The morphological characteristics of MIPs made of allyl-β-CD and MAA (M-MAA) were characterised by scanning electron microscopy. The effect of binding capacity of MAA-linked allyl-β-CD MIPs (M-MAA) demonstrated higher efficiency than that of AN-linked allyl-β-CD MIPs (M-AN) when tested in binding specificity. Finally, M-MAA was chosen to run through molecularly imprinted solid-phase extraction (MISPE) to analyse the spiked fresh leafy vegetables of pirimicarb. The present proposed technique is a promising tool for the preparation of the receptors which could recognise pirimicarb pesticide in aqueous media. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

Computer-assisted design and synthesis of molecularly imprinted polymers for selective extraction of acetazolamide from human plasma prior to its voltammetric determination.

PubMed

Khodadadian, Mehdi; Ahmadi, Farhad

2010-06-15

Molecularly imprinted polymers (MIPs) were computationally designed and synthesized for the selective extraction of a carbonic anhydrase inhibitor, i.e. acetazolamide (ACZ), from human plasma. Density functional theory (DFT) calculations were performed to study the intermolecular interactions in the pre-polymerization mixture and to find a suitable functional monomer in MIP preparation. The interaction energies were corrected for the basis set superposition error (BSSE) using the counterpoise (CP) correction. The polymerization solvent was simulated by means of polarizable continuum model (PCM). It was found that acrylamide (AAM) is the best candidate to prepare MIPs. To confirm the results of theoretical calculations, three MIPs were synthesized with different functional monomers and evaluated using Langmuir-Freundlich (LF) isotherm. The results indicated that the most homogeneous MIP with the highest number of binding sites is the MIP prepared by AAM. This polymer was then used as a selective adsorbent to develop a molecularly imprinted solid-phase extraction procedure followed by differential pulse voltammetry (MISPE-DPV) for clean-up and determination of ACZ in human plasma.

Chiral imprinted polymers as enantiospecific coatings of stir bar sorptive extraction devices.

PubMed

Gomez-Caballero, Alberto; Guerreiro, Antonio; Karim, Kal; Piletsky, Sergey; Goicolea, M Aranzazu; Barrio, Ramon J

2011-10-15

This paper reports the design of Molecularly Imprinted Polymers (MIP) with affinity towards (S)-citalopram using computational modeling for the selection of functional monomers and monomer:template ratio. Acrylamide was selected as functional monomer and the final complex functional monomer/template resulted in a 3:1 ratio. The polymer was synthesized by radical polymerization initiated by UV onto magnetic stir-bars in order to obtain a stir bar sorptive extraction (SBSE) device capable of selective enantiomeric recognition. After successful template removal, the parameters affecting the SBSE procedure (sample volume, ionic strength, extraction time and pH) were optimized for the effective rebinding of the target analyte. The resultant chirally imprinted polymer based stir-bar was able to selectively extract (S)-citalopram from a racemic mixture in an aqueous media with high specificity (specificity factor 4) between 25 and 500 μgL(-1). The MIP coated stir-bars can have significance for enantiospecific sample pre-concentration and subsequent analysis without the need for any chiral chromatographic separation. Copyright © 2011 Elsevier B.V. All rights reserved.

Bioimprinted QCM sensors for virus detection-screening of plant sap.

PubMed

Dickert, Franz L; Hayden, Oliver; Bindeus, Roland; Mann, Karl-J; Blaas, Dieter; Waigmann, Elisabeth

2004-04-01

Surface imprinting techniques on polymer-coated quartz-crystal microbalances (QCM) have been used to detect tobacco mosaic viruses (TMV) in aqueous media. Molecularly imprinted polymers (MIP), tailor-made by self organisation of monomers around a template (TMV), were generated directly on the gold electrodes. Imprinted trenches on the polymer surface mimicking the shape and surface functionality of the virus serve as recognition sites for re-adsorption after washing out of the template. The sensors are applicable to TMV detection ranging from 100 ng mL(-1) to 1 mg mL(-1) within minutes. Furthermore, direct measurements without time-consuming sample preparation are possible in complex matrices such as tobacco plant sap.

Oxytetracycline recovery from aqueous media using computationally designed molecularly imprinted polymers.

PubMed

Rodríguez-Dorado, Rosalía; Carro, Antonia M; Chianella, Iva; Karim, Kal; Concheiro, Angel; Lorenzo, Rosa A; Piletsky, Sergey; Alvarez-Lorenzo, Carmen

2016-09-01

Polymers for recovery/removal of the antimicrobial agent oxytetracycline (OTC) from aqueous media were developed with use of computational design and molecular imprinting. 2-Hydroxyethyl methacrylate, 2-acrylamide-2-methylpropane sulfonic acid (AMPS), and mixtures of the two were chosen according to their predicted affinity for OTC and evaluated as functional monomers in molecularly imprinted polymers and nonimprinted polymers. Two levels of AMPS were tested. After bulk polymerization, the polymers were crushed into particles (200-1000 μm). Pressurized liquid extraction was implemented for template removal with a low amount of methanol (less than 20 mL in each extraction) and a few extractions (12-18 for each polymer) in a short period (20 min per extraction). Particle size distribution, microporous structure, and capacity to rebind OTC from aqueous media were evaluated. Adsorption isotherms obtained from OTC solutions (30-110 mg L(-1)) revealed that the polymers prepared with AMPS had the highest affinity for OTC. The uptake capacity depended on the ionic strength as follows: purified water > saline solution (0.9 % NaCl) > seawater (3.5 % NaCl). Polymer particles containing AMPS as a functional monomer showed a remarkable ability to clean water contaminated with OTC. The usefulness of the stationary phase developed for molecularly imprinted solid-phase extraction was also demonstrated. Graphical Abstract Selection of functional monomers by molecular modeling renders polymer networks suitable for removal of pollutants from contaminated aqueous environments, under either dynamic or static conditions.

Virtual imprinting as a tool to design efficient MIPs for photosynthesis-inhibiting herbicides.

PubMed

Breton, Florent; Rouillon, Regis; Piletska, Elena V; Karim, Kal; Guerreiro, Antonio; Chianella, Iva; Piletsky, Sergey A

2007-04-15

Molecular modelling and computational screening were used to identify functional monomers capable of interacting with several different photosynthesis-inhibiting herbicides. The process involved the design of a virtual library of molecular models of functional monomers containing polymerizable residues and residues able to interact with the template through electrostatic, hydrophobic, Van der Waals forces and dipole-dipole interactions. Each of the entries in the virtual library was probed for its possible interactions with molecular models of the template molecules. It was anticipated that the monomers giving the highest binding score would represent good candidates for the preparation of affinity polymers. Strong interactions were computationally determined between acidic functional monomers like methacrylic acid (MAA) or itaconic acid (IA) with triazines, and between vinylimidazole with bentazone and bromoxynil. Nevertheless, weaker interactions were seen with phenylureas. The corresponding blank polymers were prepared using the selected monomers and tested in the solid phase extraction (SPE) of herbicides from chloroform solutions. A good correlation was found between the binding score of the monomers and the affinities of the corresponding polymers. The use of computationally designed blanks can potentially eliminate the need for molecular imprinting, (adding a template to the monomer mixture to create specific binding sites). Data also showed that some monomers have a natural selectivity for some herbicides, which can be further enhanced by imprinting. Thus, in regard to retention on the blank polymer, we can estimate if the resulting imprinted polymer will be effective or not.

Establishment and functions of DNA methylation in the germline

PubMed Central

Stewart, Kathleen R; Veselovska, Lenka; Kelsey, Gavin

2016-01-01

Epigenetic modifications established during gametogenesis regulate transcription and other nuclear processes in gametes, but also have influences in the zygote, embryo and postnatal life. This is best understood for DNA methylation which, established at discrete regions of the oocyte and sperm genomes, governs genomic imprinting. In this review, we describe how imprinting has informed our understanding of de novo DNA methylation mechanisms, highlight how recent genome-wide profiling studies have provided unprecedented insights into establishment of the sperm and oocyte methylomes and consider the fate and function of gametic methylation and other epigenetic modifications after fertilization. PMID:27659720

Survey of Human Systems Integration (HSI) Tools for USCG Acquisitions

DTIC Science & Technology

2009-04-01

an IMPRINT HPM. IMPRINT uses task network modeling to represent human performance. As the name implies, task networks use a flowchart type format...tools; and built-in tutoring support for beginners . A perceptual/motor layer extending ACT-R’s theory of cognition to perception and action is also...chisystems.com B.8 Information and Functional Flow Analysis Description In information flow analysis, a flowchart of the information and decisions

Selection of imprinted nanoparticles by affinity chromatography.

PubMed

Guerreiro, António R; Chianella, Iva; Piletska, Elena; Whitcombe, Michael J; Piletsky, Sergey A

2009-04-15

Soluble molecularly imprinted nanoparticles were synthesised via iniferter initiated polymerisation and separated by size via gel permeation chromatography. Subsequent fractionation of these particles by affinity chromatography allowed the separation of high affinity fractions from the mixture of nanoparticles. Fractions selected this way possess affinity similar to that of natural antibodies (K(d) 6.6x10(-8)) M and were also able to discriminate between related functional analogues of the template.

Preparation and application of epitope magnetic molecularly imprinted polymers for enrichment of sulfonamide antibiotics in water.

PubMed

Hu, Yufeng; Wang, Cheng; Li, Xiangdao; Liu, Lifen

2017-10-01

Sulfonamides, which are widely used synthetic antibiotics, are hydrophilic and stable. They can easily migrate into the environment and aquatic animals, and increase the risk of cancer, drug resistance, and allergic symptoms if consumed by humans. Here, we developed an epitope magnetic imprinting approach to enrich multiple sulfonamide antibiotics from a water sample. Epitope magnetic molecularly imprinted polymers (EMMIPs) were prepared by free-radical polymerization using vinyl-functioned Fe 3 O 4 as a core, sulfanilamide (SA) as a dummy template, methacrylic acid as a functional monomer, and ethylene glycol dimethacrylate as a cross-linker. The performance of the EMMIPs was first evaluated by rebinding SA, and then an adsorption experiment was conducted to assess the extraction of multiple sulfonamide antibiotics containing the SA group. The binding experiments showed that the EMMIPs reached adsorption equilibrium in only 5 min with adsorption of SA at 2040 μg/g, compared with just 462 μg/g for the epitope magnetic non-imprinted polymers. EMMIPs were combined with HPLC for the detection of six sulfonamide antibiotics in surface water samples. The recoveries ranged from 79.3 to 92.4% and the relative standard deviations from 0.9 to 7.3%. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Multi-dimensional single-spin nano-optomechanics with a levitated nanodiamond

NASA Astrophysics Data System (ADS)

Neukirch, Levi P.; von Haartman, Eva; Rosenholm, Jessica M.; Nick Vamivakas, A.

2015-10-01

Considerable advances made in the development of nanomechanical and nano-optomechanical devices have enabled the observation of quantum effects, improved sensitivity to minute forces, and provided avenues to probe fundamental physics at the nanoscale. Concurrently, solid-state quantum emitters with optically accessible spin degrees of freedom have been pursued in applications ranging from quantum information science to nanoscale sensing. Here, we demonstrate a hybrid nano-optomechanical system composed of a nanodiamond (containing a single nitrogen-vacancy centre) that is levitated in an optical dipole trap. The mechanical state of the diamond is controlled by modulation of the optical trapping potential. We demonstrate the ability to imprint the multi-dimensional mechanical motion of the cavity-free mechanical oscillator into the nitrogen-vacancy centre fluorescence and manipulate the mechanical system's intrinsic spin. This result represents the first step towards a hybrid quantum system based on levitating nanoparticles that simultaneously engages optical, phononic and spin degrees of freedom.

Preparation of microspheric Fe(III)-ion imprinted polymer for selective solid phase extraction

NASA Astrophysics Data System (ADS)

Ara, Behisht; Muhammad, Mian; Salman, Muhammad; Ahmad, Raees; Islam, Noor; Zia, Tanveer ul Haq

2018-03-01

In this research work, an Fe(III)-IIP was prepared using methacrylic acid as monomer, divinylbenzene as cross-linker, azobisisobutyronitrile as initiator. The ion imprinted polymer was functionalized with Fe(III)8-hydroxy quinolone complex under thermal conditions by copolymerization with the monomer and the cross-linker. The prepared Fe(III)-ion imprinted polymer (IIP) and non-ion imprinted polymer (Non-IIP) were characterized with fourier transform-infrared spectroscopy, scanning electron microscopic analysis and thermal gravimetric analysis. The polymer showed a good stability to thermal analysis up to a temperature of 500 °C. The size of the polymer obtained was 1 µm, large enough to be filtered easily. At pH 2.5 more affinity was observed with ion imprinted polymer in comparison to non-ion imprinted polymer. For the kinetic study, the most linear and rhythmical relation were seen in pseudo second order. The maximum sorption capacity of Fe(III) ions on Fe(III)-IIP and non-IIP was 170 and 30.0 µmolg-1, respectively. The relative selectivity factor (αr) values of Fe(III)/Fe(II), Fe(III)/Al(III) and Fe(III)/Cr(III) were 151.0, 84.6 and 91.9, respectively. The preconcentration factor was found to be 240. The developed method was successfully applied to the determination of trace Fe in the drinking water.

Improvement of imprinting effect of ionic liquid molecularly imprinted polymers by use of a molecular crowding agent.

PubMed

Jia, Man; Yang, Jian; Sun, Ya Kun; Bai, Xi; Wu, Tao; Liu, Zhao Sheng; Aisa, Haji Akber

2018-01-01

We aimed to improve the imprinting effect of ionic liquid molecularly imprinted polymers (MIPs) by use of a molecular crowding agent. The ionic liquid 1-vinyl-3-ethylimidazolium tetrafluoroborate ([VEIm][BF 4 ]) was used as the functional monomer and aesculetin was used as the template molecule in a crowding environment, which was made up of a tetrahydrofuran solution of polystyrene. The ionic liquid MIPs that were prepared in the crowding environment displayed an enhanced imprinting effect. NMR peak shifts of active hydrogen of aesculetin suggested that interaction between the functional monomer and the template could be increased by the use of a crowding agent in the self-assembly process. The retention and selectivity of aesculetin were affected greatly by high molecular crowding, the amount of high molecular weight crowding agent, and the ratio of [VEIm][BF 4 ] to aesculetin. The optimal MIPs were used as solid-phase extraction sorbents to extract aesculetin from Cichorium glandulosum. A calibration curve was obtained with aesculetin concentrations from 0.0005 to 0.05 mg mL -1 (correlation coefficient R 2 of 0.9999, y = 1519x + 0.0923). The limit of quantification was 0.12 μg mL -1 , and the limit of detection was 0.05 μg mL -1 . The absolute recovery of aesculetin was (80 ± 2)% (n = 3), and the purity of aesculetin was (92 ± 0.5)% (n = 5). As a conclusion, molecular crowding is an effective approach to obtain ionic liquid MIPs with high selectivity even in a polar solvent environment.

Electrochemical Sensor Based on Rh(III) Ion-Imprinted Polymer as a New Modifying Agent for Rhodium Determination.

PubMed

Bai, Huiping; Xiong, Caiyun; Wang, Chunqiong; Liu, Peng; Dong, Su; Cao, Qiue

2018-05-01

A rhodium (III) ion carbon paste electrode (CPE) based on an ion imprinted polymer (IIP) as a new modifying agent has been prepared and studied. Rh(III) ion imprinted polymer was synthesized by copolymerization of acrylamide-Rh(III) complex and ethylene glycol dimethacrylate according to the precipitation polymerization. Acrylamide acted as both functional monomer and complexing agent to create selective coordination sites in a cross-linked polymer. The ion imprinted carbon paste electrode (IIP-CPE) was prepared by mixing rhodium IIP-nanoparticles and graphite powder in n-eicosane as an adhesive and then embedding them in a Teflon tube. Amperometric i-t curve method was applied as the determination technique. Several parameters, including the functional monomer, molar ratio of template, monomer and cross-linking agent, the amounts of IIP, the applied potential, the buffer solution and pH have been studied. According to the results, IIP-CPE showed a considerably higher response in comparison with the electrode embedded with non-imprinted polymer (NIP), indicating the formation of suitable recognition sites in the IIP structure during the polymerization stage. The introduced electrode showed a linear range of 1.00×10-8~3.0×10-5 mol·L-1 and detection limit of 6.0 nmol L-1 (S/N = 3). The IIP-CPE was successfully applied for the trace rhodium determination in catalyst and plant samples with RSD of less than 3.3% (n = 5) and recoveries in the range of 95.5~102.5%.

Probing chromatin structure with nuclease sensitivity assays.

PubMed

Gregory, R I; Khosla, S; Feil, R

2001-01-01

To further our understanding of genomic imprinting it will be essential to identify key control elements, and to investigate their regulation by both epigenetic modifications (such as DNA methylation) and trans-acting factors. So far, sequence elements that regulate parental allele-specific gene expression have been identified in a number of imprinted loci, either because of their differential DNA methylation or through functional studies in transgenic mice (1,2). A systematic search for allele-specific chromatin features constitutes an alternative strategy to identify elements that regulate imprinting. The validity of such an in vivo chromatin approach derives from the fact that in several known imprinting control-elements, a specialized organization of chromatin characterized by nuclease hypersensitivity is present on only one of the two parental chromosome (3). For example, the differentially methylated 5 -portion of the human SNRPN gene-a sequence element that controls imprinting in the Prader-Willi and Angelman syndromes' domain on chromosome 15q11- q13-has strong DNase-I hypersensitive sites on the unmethylated paternal chromosome (4). A differentially methylated region that regulates the imprinting of H19 and that of the neighboring insulin-like growth factor-2 gene on mouse chromosome 7 was also found to have parental chromosome-specific hypersensitive sites (5,6). The precise nature of the allelic nuclease hypersensitivity in these and other imprinted loci remains to be determined in more detail, for example, by applying complementary chromatin methodologies (7,8). However, it is commonly observed that a nuclease hypersensitive site corresponds to a small region where nucleosomes are absent or partially disrupted.

Involvement of nucleotide diphosphate kinase 2 in the reopening of the sensitive period of filial imprinting of domestic chicks (Gallus gallus domesticus).

PubMed

Yamaguchi, Shinji; Aoki, Naoya; Takehara, Akihiko; Mori, Masaru; Kanai, Akio; Matsushima, Toshiya; Homma, Koichi J

2016-01-26

Filial imprinting is a behavior characterized by the sensitive or critical period restricted to the first few days after hatching. Once the sensitive period is closed, it is widely believed that chicks can never be imprinted under natural conditions. Previously, we showed that the exogenous injection of T3 reopened the sensitive period which was already closed. That study suggested that T3 functioned by way of a rapid non-genomic action; however, the molecular mechanism of how T3 reopens the sensitive period remains unknown. Here, we show that the phosphorylation level of nucleotide diphosphate kinase 2 (NDPK2) was upregulated following T3 injection. Pharmacological deprivation of the kinase activity of NDPK hampered the molecular process prerequisite for the reopening of the sensitive period of filial imprinting. Moreover, it is shown that the kinase activity of NDPK2 participates in the priming process by T3 signaling which endows the potential for learning. Our data indicate that NDPK2 plays a crucial role downstream of T3 action and that its phosphorylation is involved in the non-genomic signaling during imprinting. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Angelman syndrome-derived neurons display late onset of paternal UBE3A silencing

PubMed Central

Stanurova, Jana; Neureiter, Anika; Hiber, Michaela; de Oliveira Kessler, Hannah; Stolp, Kristin; Goetzke, Roman; Klein, Diana; Bankfalvi, Agnes; Klump, Hannes; Steenpass, Laura

2016-01-01

Genomic imprinting is an epigenetic phenomenon resulting in parent-of-origin-specific gene expression that is regulated by a differentially methylated region. Gene mutations or failures in the imprinting process lead to the development of imprinting disorders, such as Angelman syndrome. The symptoms of Angelman syndrome are caused by the absence of functional UBE3A protein in neurons of the brain. To create a human neuronal model for Angelman syndrome, we reprogrammed dermal fibroblasts of a patient carrying a defined three-base pair deletion in UBE3A into induced pluripotent stem cells (iPSCs). In these iPSCs, both parental alleles are present, distinguishable by the mutation, and express UBE3A. Detailed characterization of these iPSCs demonstrated their pluripotency and exceptional stability of the differentially methylated region regulating imprinted UBE3A expression. We observed strong induction of SNHG14 and silencing of paternal UBE3A expression only late during neuronal differentiation, in vitro. This new Angelman syndrome iPSC line allows to study imprinted gene regulation on both parental alleles and to dissect molecular pathways affected by the absence of UBE3A protein. PMID:27484051

Coatings of molecularly imprinted polymers based on polyhedral oligomeric silsesquioxane for open tubular capillary electrochromatography.

PubMed

Zhao, Qing-Li; Zhou, Jin; Zhang, Li-Shun; Huang, Yan-Ping; Liu, Zhao-Sheng

2016-05-15

Polyhedral oligomeric silsesquioxane (POSS) was successfully applied, for the first time, to prepare imprinted monolithic coating for capillary electrochromatography. The imprinted monolithic coating was synthesized with a mixture of PSS-(1-Propylmethacrylate)-heptaisobutyl substituted (MA 0702), S-amlodipine (template), methacrylic acid (functional monomer), and 2-methacrylamidopropyl methacrylate (crosslinker), in a porogenic mixture of toluene-isooctane. The influence of synthesis parameters on the imprinting effect and separation performance, including the amount of MA 0702, the ratio of template to monomer, and the ratio of monomer to crosslinker, was investigated. The greatest resolution for enantiomers separation on the imprinted monolithic column prepared with MA 0702 was up to 22.3, about 2 times higher than that prepared in absence of the POSS. Column efficiency on the POSS-based MIP coatings was beyond 30,000 plate m(-1). The comparisons between MIP coating synthesized with the POSS and without the POSS were made in terms of selectivity, column efficiency, and resolution. POSS-based MIP capillaries with naproxen or zopiclone was also prepared and separation of enantiomers can be achieved. Copyright © 2016 Elsevier B.V. All rights reserved.

Computational Optimization and Characterization of Molecularly Imprinted Polymers

NASA Astrophysics Data System (ADS)

Terracina, Jacob J.

Molecularly imprinted polymers (MIPs) are a class of materials containing sites capable of selectively binding to the imprinted target molecule. Computational chemistry techniques were used to study the effect of different fabrication parameters (the monomer-to-target ratios, pre-polymerization solvent, temperature, and pH) on the formation of the MIP binding sites. Imprinted binding sites were built in silico for the purposes of better characterizing the receptor - ligand interactions. Chiefly, the sites were characterized with respect to their selectivities and the heterogeneity between sites. First, a series of two-step molecular mechanics (MM) and quantum mechanics (QM) computational optimizations of monomer -- target systems was used to determine optimal monomer-to-target ratios for the MIPs. Imidazole- and xanthine-derived target molecules were studied. The investigation included both small-scale models (one-target) and larger scale models (five-targets). The optimal ratios differed between the small and larger scales. For the larger models containing multiple targets, binding-site surface area analysis was used to evaluate the heterogeneity of the sites. The more fully surrounded sites had greater binding energies. Molecular docking was then used to measure the selectivities of the QM-optimized binding sites by comparing the binding energies of the imprinted target to that of a structural analogue. Selectivity was also shown to improve as binding sites become more fully encased by the monomers. For internal sites, docking consistently showed selectivity favoring the molecules that had been imprinted via QM geometry optimizations. The computationally imprinted sites were shown to exhibit size-, shape-, and polarity-based selectivity. This represented a novel approach to investigate the selectivity and heterogeneity of imprinted polymer binding sites, by applying the rapid orientation screening of MM docking to the highly accurate QM-optimized geometries. Next, we sought to computationally construct and investigate binding sites for their enantioselectivity. Again, a two-step MM [special characters removed] QM optimization scheme was used to "computationally imprint" chiral molecules. Using docking techniques, the imprinted binding sites were shown to exhibit an enantioselective preference for the imprinted molecule over its enantiomer. Docking of structurally similar chiral molecules showed that the sites computationally imprinted with R- or S-tBOC-tyrosine were able to differentiate between R- and S-forms of other tyrosine derivatives. The cross-enantioselectivity did not hold for chiral molecules that did not share the tyrosine H-bonding functional group orientations. Further analysis of the individual monomer - target interactions within the binding site led us to conclude that H-bonding functional groups that are located immediately next to the target's chiral center, and therefore spatially fixed relative to the chiral center, will have a stronger contribution to the enantioselectivity of the site than those groups separated from the chiral center by two or more rotatable bonds. These models were the first computationally imprinted binding sites to exhibit this enantioselective preference for the imprinted target molecules. Finally, molecular dynamics (MD) was used to quantify H-bonding interactions between target molecules, monomers, and solvents representative of the pre-polymerization matrix. It was found that both target dimerization and solvent interference decrease the number of monomer - target H-bonds present. Systems were optimized via simulated annealing to create binding sites that were then subjected to molecular docking analysis. Docking showed that the presence of solvent had a detrimental effect on the sensitivity and selectivity of the sites, and that solvents with more H-bonding capabilities were more disruptive to the binding properties of the site. Dynamic simulations also showed that increasing the temperature of the solution can significantly decrease the number of H-bonds formed between the targets and monomers. It is believed that the monomer - target complexes formed within the pre-polymerization matrix are translated into the selective binding cavities formed during polymerization. Elucidating the nature of these interactions in silico improves our understanding of MIPs, ultimately allowing for more optimized sensing materials.

Molecularly imprinted polymers for RGD selective recognition and separation.

PubMed

Papaioannou, Emmanuel; Koutsas, Christos; Liakopoulou-Kyriakides, Maria

2009-03-01

Molecularly imprinted polymers that could recognize the tripeptide Arg-Gly-Asp have been produced with the use of two functional monomers and three different cross-linkers, respectively. Methacrylic acid and acrylamide were used as functional monomers and the role of the ethylene glycol dimethacrylate, trimethylpropane trimethacrylate and N,N'-methylene-bisacrylamide as crosslinking monomers, was investigated on their recognition capability. The % net rebinding and the imprinting factor values were obtained, giving for the methacrylic acid-trimethylpropane trimethacrylate polymer the highest values 12.3% and 2.44, respectively. In addition, this polymer presented lower dissociation constant (K(D)) value and the higher B (max)% of theoretical total binding sites than all the other polymers. Rebinding experiments with Lys-Gly-Asp, an analogue of Arg-Gly-Asp, and other different peptides, such as cholecystokinin C-terminal tri- and pentapeptide and gramicidin, further indicated the selectivity of methacrylic acid-trimethylpropane trimethacrylate copolymer for Arg-Gly-Asp giving specific selectivity factor values 1.27, 1.98, 1.31 and 1.67, respectively.

Molecular imprinted polymer functionalized carbon nanotube sensors for detection of saccharides

NASA Astrophysics Data System (ADS)

Badhulika, Sushmee; Mulchandani, Ashok

2015-08-01

In this work, we report the synthesis and fabrication of an enzyme-free sugar sensor based on molecularly imprinted polymer (MIP) on the surface of single walled carbon nanotubes (SWNTs). Electropolymerization of 3-aminophenylboronic acid (3-APBA) in the presence of 10 M d-fructose and fluoride at neutral pH conditions resulted in the formation of a self-doped, molecularly imprinted conducting polymer (MICP) via the formation of a stable anionic boronic ester complex between poly(aniline boronic acid) and d-fructose. Template removal generated binding sites on the polymer matrix that were complementary to d-fructose both in structure, i.e., shape, size, and positioning of functional groups, thus enabling sensing of d-fructose with enhanced affinity and specificity over non-MIP based sensors. Using carbon nanotubes along with MICPs helped to develop an efficient electrochemical sensor by enhancing analyte recognition and signal generation. These sensors could be regenerated and used multiple times unlike conventional affinity based biosensors which suffer from physical and chemical stability.

Regulatory Elements Associated with Paternally-Expressed Genes in the Imprinted Murine Angelman/Prader-Willi Syndrome Domain

PubMed Central

Khadake, Jyoti; Heggestad, Arnold D.; Ma, Xiaojie; Johnstone, Karen A.; Resnick, James L.; Yang, Thomas P.

2013-01-01

The Angelman/Prader-Willi syndrome (AS/PWS) domain contains at least 8 imprinted genes regulated by a bipartite imprinting center (IC) associated with the SNRPN gene. One component of the IC, the PWS-IC, governs the paternal epigenotype and expression of paternal genes. The mechanisms by which imprinting and expression of paternal genes within the AS/PWS domain – such as MKRN3 and NDN – are regulated by the PWS-IC are unclear. The syntenic region in the mouse is organized and imprinted similarly to the human domain with the murine PWS-IC defined by a 6 kb interval within the Snrpn locus that includes the promoter. To identify regulatory elements that may mediate PWS-IC function, we mapped the location and allele-specificity of DNase I hypersensitive (DH) sites within the PWS-IC in brain cells, then identified transcription factor binding sites within a subset of these DH sites. Six major paternal-specific DH sites were detected in the Snrpn gene, five of which map within the 6 kb PWS-IC. We postulate these five DH sites represent functional components of the murine PWS-IC. Analysis of transcription factor binding within multiple DH sites detected nuclear respiratory factors (NRF's) and YY1 specifically on the paternal allele. NRF's and YY1 were also detected in the paternal promoter region of the murine Mrkn3 and Ndn genes. These results suggest that NRF's and YY1 may facilitate PWS-IC function and coordinately regulate expression of paternal genes. The presence of NRF's also suggests a link between transcriptional regulation within the AS/PWS domain and regulation of respiration. 3C analyses indicated Mkrn3 lies in close proximity to the PWS-IC on the paternal chromosome, evidence that the PWS-IC functions by allele-specific interaction with its distal target genes. This could occur by allele-specific co-localization of the PWS-IC and its target genes to transcription factories containing NRF's and YY1. PMID:23390487

MRI screening of kindred at risk of developing paragangliomas: support for genomic imprinting in hereditary glomus tumours.

PubMed Central

van Gils, A. P.; van der Mey, A. G.; Hoogma, R. P.; Sandkuijl, L. A.; Maaswinkel-Mooy, P. D.; Falke, T. H.; Pauwels, E. K.

1992-01-01

Paragangliomas of the head and neck (glomus tumours) can occur in a hereditary pattern and may be hormonally active as well as being associated with paragangliomas elsewhere. A number of these tumours may be present without symptoms. To detect the presence of subclinical paragangliomas we screened 83 members of a family at risk of developing hereditary paragangliomas using whole body MRI and urinary catecholamine testing. In eight previously diagnosed members, eight known glomus tumours of which one functioning, and two unknown glomus tumours and one unknown pheochromocytoma were present. Six unsuspected members showed ten glomus tumours and one pheochromocytoma. It has been suggested that the manifestation of hereditary glomus tumours is determined by the sex of the transmitting parent. There were no tumours in the descendants of female gene carriers. Comparing the likelihood of inheritance with genomic imprinting versus inheritance without genomic imprinting we found an odds ratio of 23375 in favour of genomic imprinting. PMID:1616861

Fluorescence measurements of activity associated with a molecularly imprinted polymer imprinted to dipicolinic acid

NASA Astrophysics Data System (ADS)

Anderson, John; Pestov, Dmitry; Fischer, Robert L.; Webb, Stanley; Tepper, Gary C.

2004-03-01

Steady state and lifetime fluorescence measurements were acquired to measure the binding activity associated with molecularly imprinted polymer (MIP) microparticles imprinted to dipicolinic acid. Dipicolinic acid is a unique compound associated with the sporulation phase of spore-forming bacteria (e.g., genus Bacillus and Clostridium). Vinylic monomers were polymerized in a dimethylformamide solution containing the dipicolinic acid as a template. The resulting MIP was then pulverized and size selected into small microscale particles. Samplers were adapted incorporating the MIP particles within a dialyzer (500 MW). Tests were run on replicate samples of biologically active cultures representing both stationary phase and sporulation post fermentation products in standard media. The permeability of the membrane permitted diffusion of lighter molecular weight constituents from media effluents to enter the dialyzer chamber and contact the MIP. Extractions of the media were measured using steady state and lifetime fluorescence. Results showed dramatic steady state fluorescence changes as a function of excitation, emission and intensity and an estimated lifetime of 5.8 ns.

Determination of ractopamine in pork using a magnetic molecularly imprinted polymer as adsorbent followed by HPLC.

PubMed

Tang, Yiwei; Gao, Jingwen; Liu, Xiuying; Lan, Jianxing; Gao, Xue; Ma, Yong; Li, Min; Li, Jianrong

2016-06-15

A new magnetic molecularly imprinted polymers (MMIPs) for separation and concentration of ractopamine (RAC) were prepared using surface molecular imprinting technique with methacryloyl chloride as functional monomer and RAC as template. The MMIPs were characterized using transmission electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction, and vibrating sample magnetometer. The results of re-binding experiments indicated that the MMIPs had fast adsorption kinetics and could reach binding equilibrium within 20 min, and the adsorption capacity of the MMIPs was 2.87-fold higher than that of the corresponding non-imprinted polymer. The selectivity of the MMIPs was evaluated according to its recognition to RAC and its analogues. The synthesized MMIPs were successfully applied to extraction, followed by high performance liquid chromatography to determine RAC in real food samples. Spiked recoveries ranged from 73.60% to 94.5%, with relative standard deviations of <11.17%. Copyright © 2016 Elsevier Ltd. All rights reserved.

Solvent immersion imprint lithography: A high-performance, semi-automated procedure

PubMed Central

Liyu, D. A.; Canul, A. J.; Vasdekis, A. E.

2017-01-01

We expand upon our recent, fundamental report on solvent immersion imprint lithography (SIIL) and describe a semi-automated and high-performance procedure for prototyping polymer microfluidics and optofluidics. The SIIL procedure minimizes manual intervention through a cost-effective (∼$200) and easy-to-assemble apparatus. We analyze the procedure's performance specifically for Poly (methyl methacrylate) microsystems and report repeatable polymer imprinting, bonding, and 3D functionalization in less than 5 min, down to 8 μm resolutions and 1:1 aspect ratios. In comparison to commercial approaches, the modified SIIL procedure enables substantial cost reductions, a 100-fold reduction in imprinting force requirements, as well as a more than 10-fold increase in bonding strength. We attribute these advantages to the directed polymer dissolution that strictly localizes at the polymer-solvent interface, as uniquely offered by SIIL. The described procedure opens new desktop prototyping opportunities, particularly for non-expert users performing live-cell imaging, flow-through catalysis, and on-chip gas detection. PMID:28798847

New potentiometric sensor based on molecularly imprinted nanoparticles for cocaine detection.

PubMed

Smolinska-Kempisty, K; Ahmad, O Sheej; Guerreiro, A; Karim, K; Piletska, E; Piletsky, S

2017-10-15

Here we present a potentiometric sensor for cocaine detection based on molecularly imprinted polymer nanoparticles (nanoMIPs) produced by the solid-phase imprinting method. The composition of polymers with high affinity for cocaine was optimised using molecular modelling. Four compositions were selected and polymers prepared using two protocols: chemical polymerisation in water and UV-initiated polymerisation in organic solvent. All synthesised nanoparticles had very good affinity to cocaine with dissociation constants between 0.6nM and 5.3nM. Imprinted polymers produced in organic solvent using acrylamide as a functional monomer demonstrated the highest yield and affinity, and so were selected for further sensor development. For this, nanoparticles were incorporated within a PVC matrix which was then used to prepare an ion-selective membrane integrated with a potentiometric transducer. It was demonstrated that the sensor was able to quantify cocaine in blood serum samples in the range of concentrations between 1nM and 1mM. Copyright © 2017 Elsevier B.V. All rights reserved.

Modular Polymer Biosensors by Solvent Immersion Imprint Lithography

DOE Office of Scientific and Technical Information (OSTI.GOV)

Moore, Jayven S.; Xantheas, Sotiris S.; Grate, Jay W.

2016-01-01

We recently demonstrated Solvent Immersion Imprint Lithography (SIIL), a rapid benchtop microsystem prototyping technique, including polymer functionalization, imprinting and bonding. Here, we focus on the realization of planar polymer sensors using SIIL through simple solvent immersion without imprinting. We describe SIIL’s impregnation characteristics, including an inherent mechanism that not only achieves practical doping concentrations, but their unexpected 4-fold enhancement compared to the immersion solution. Subsequently, we developed and characterized optical sensors for detecting molecular O2. To this end, a high dynamic range is reported, including its control through the immersion duration, a manifestation of SIIL’s modularity. Overall, SIIL exhibits themore » potential of improving the operating characteristics of polymer sensors, while significantly accelerating their prototyping, as it requires a few seconds of processing and no need for substrates or dedicated instrumentation. These are critical for O2 sensing as probed by way of example here, as well as any polymer permeable reactant.« less

Prader-Willi syndrome: intellectual abilities and behavioural features by genetic subtype.

PubMed

Milner, Katja M; Craig, Ellen E; Thompson, Russell J; Veltman, Marijcke W M; Thomas, N Simon; Roberts, Sian; Bellamy, Margaret; Curran, Sarah R; Sporikou, Caroline M J; Bolton, Patrick F

2005-10-01

Studies of chromosome 15 abnormality have implicated over-expression of paternally imprinted genes in the 15q11-13 region in the aetiology of autism. To test this hypothesis we compared individuals with Prader-Willi syndrome (PWS) due to uniparental disomy (UPD--where paternally imprinted genes are over-expressed) to individuals with the 15q11-13 deletion form of the syndrome (where paternally imprinted genes are not over-expressed). We also tested reports that PWS cases due to the larger type I (TI) form of deletion show differences to cases with the smaller type II (TII) deletion. Ninety-six individuals with PWS were recruited from genetic centres and the PWS association. Forty-nine individuals were confirmed as having maternal UPD of chromosome 15 and were age and sex matched to 47 individuals with a deletion involving 15q11-13 (32 had the shorter (T II) deletion, and 14 had the longer (TI) deletion). Behavioural assessments were carried out blind to genetic status, using the Autism Diagnostic Observation Schedule (ADOS), the Autism Diagnostic Interview (ADI), the Autism Screening Questionnaire (ASQ), the Children's Yale-Brown Obsessive-Compulsive Scale (CY-BOCS), the Vineland Adaptive Behaviour Scales (VABS), and measurements of intellectual ability, including the Wechsler and Mullen Scales and Raven's Matrices. UPD cases exhibited significantly more autistic-like impairments in reciprocal social interaction on questionnaire, interview and standardised observational measures. Comparison of TI and TII deletion cases revealed few differences, but ability levels tended to be lower in the TI deletion cases. Findings from a large study comparing deletion and UPD forms of Prader-Willi syndrome were consistent with other evidence in indicating that paternally imprinted genes in the 15q11-13 region constitute a genetic risk factor for aspects of autistic symptomatology. These genes may therefore play a role in the aetiology of autism. By contrast with another report, there was no clear-cut relationship between the size of the deletion and the form of cognitive and behavioural phenotype.

Preparation of molecular imprinted microspheres based on inorganic-organic co-functional monomer for miniaturized solid-phase extraction of fluoroquinolones in milk.

PubMed

Wang, Hui; Wang, Ruiling; Han, Yehong

2014-02-15

An inorganic-organic co-functional monomer, methacrylic acid-vinyltriethoxysilan (MAA-VTES) was designed for the synthesis of molecularly imprinted microspheres (MIMs). By virtue of the aqueous suspension polymerization and dummy template (pazufloxacin), the obtained MAA-VTES based MIMs exhibited good recognition and selectivity to fluoroquinolones (FQs), and were successfully applied as selective sorbents of a miniaturized home-made solid phase extraction device for the determination of ofloxacin (OFL), lomefloxacin (LOM) and ciprofloxacin (CIP) in milk samples. Under the optimum conditions of the miniaturized molecularly imprinted solid phase extraction (mini-MISPE) coupled with liquid chromatography-ultraviolet detector (LC-UV), good linearities were obtained for three FQs in a range of 0.2-20.0μgmL(-1) and the average recoveries at three spiked levels were ranged from 87.2% to 106.1% with the relative standard deviation (RSD) less than 5.4%. The presented co-functional monomer based mini-MISPE-LC-UV protocol introduced the rigidity and flexibility of inorganic silicon materials, exhibited excellent extraction performance towards targets, and could be potentially applied to the determination of FQs in milk samples. Copyright © 2013 Elsevier B.V. All rights reserved.

An AP Endonuclease Functions in Active DNA Demethylation and Gene Imprinting in Arabidopsis

PubMed Central

Li, Yan; Córdoba-Cañero, Dolores; Qian, Weiqiang; Zhu, Xiaohong; Tang, Kai; Zhang, Huiming; Ariza, Rafael R.; Roldán-Arjona, Teresa; Zhu, Jian-Kang

2015-01-01

Active DNA demethylation in plants occurs through base excision repair, beginning with removal of methylated cytosine by the ROS1/DME subfamily of 5-methylcytosine DNA glycosylases. Active DNA demethylation in animals requires the DNA glycosylase TDG or MBD4, which functions after oxidation or deamination of 5-methylcytosine, respectively. However, little is known about the steps following DNA glycosylase action in the active DNA demethylation pathways in plants and animals. We show here that the Arabidopsis APE1L protein has apurinic/apyrimidinic endonuclease activities and functions downstream of ROS1 and DME. APE1L and ROS1 interact in vitro and co-localize in vivo. Whole genome bisulfite sequencing of ape1l mutant plants revealed widespread alterations in DNA methylation. We show that the ape1l/zdp double mutant displays embryonic lethality. Notably, the ape1l+/−zdp−/− mutant shows a maternal-effect lethality phenotype. APE1L and the DNA phosphatase ZDP are required for FWA and MEA gene imprinting in the endosperm and are important for seed development. Thus, APE1L is a new component of the active DNA demethylation pathway and, together with ZDP, regulates gene imprinting in Arabidopsis. PMID:25569774

Critical role of the neural pathway from the intermediate medial mesopallium to the intermediate hyperpallium apicale in filial imprinting of domestic chicks (Gallus gallus domesticus).

PubMed

Aoki, N; Yamaguchi, S; Kitajima, T; Takehara, A; Katagiri-Nakagawa, S; Matsui, R; Watanabe, D; Matsushima, T; Homma, K J

2015-11-12

Filial imprinting in precocial birds is a useful model for studying early learning and cognitive development, as it is characterized by a well-defined sensitive or critical period. We recently showed that the thyroid hormone 3,5,3'-triiodothyronine (T3) determines the onset of the sensitive period. Moreover, exogenous injection of T3 into the intermediate medial mesopallium (IMM) region (analogous to the associative cortex in mammals) enables imprinting even on post-hatch day 4 or 6 when the sensitive period has been terminated. However, the neural mechanisms downstream from T3 action in the IMM region remain elusive. Here, we analyzed the functional involvement of the intermediate hyperpallium apicale (IMHA) in T3 action. Bilateral excitotoxic ablation of the IMHA prevented imprinting in newly hatched chicks, and also suppressed the recovery of the sensitive period by systemic intra-venous or localized intra-IMM injection of T3 in day-4 chicks. In contrast to the effect in the IMM, direct injection of T3 into the IMHA did not enable imprinting in day-4 chicks. Moreover, bilateral ablation of IMHA after imprinting training impaired recall. These results suggest that the IMHA is critical for memory acquisition downstream following T3 action in the IMM and further, that it receives and retains information stored in the IMM for recall. Furthermore, both an avian adeno-associated viral construct containing an anterograde tracer (wheat-germ agglutinin) and a retrograde tracer (cholera toxin subunit B) revealed neural connections from the IMM to the IMHA. Taken together, our findings suggest that hierarchical processes from the primary area (IMM) to the secondary area (IMHA) are required for imprinting. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

Effects of endocrine disruptors on imprinted gene expression in the mouse embryo

PubMed Central

Tran, Diana A; Rivas, Guillermo E; Singh, Purnima; Pfeifer, Gerd P

2011-01-01

Environmental endocrine disruptors (EDs) are synthetic chemicals that resemble natural hormones and are known to cause epigenetic perturbations. EDs have profound effects on development and fertility. Imprinted genes had been identified as candidate susceptibility loci to environmental insults because they are functionally haploid, and because the imprints undergo epigenetic resetting between generations. To screen for possible epigenetic perturbations caused by EDs at imprinted loci, we treated pregnant mice daily between 8.5 and 12.5 days post coitum (dpc) with di-(2-ethylhexyl)-phthalate (DEHP), bisphenol A (BPA), vinclozolin (VZ) or control oil vehicle. After isolating RNA from the placenta, yolk sac, amnion, head, body, heart, liver, lung, stomach and intestines of 13.5 dpc embryos we measured the allele-specific expression of 39 imprinted transcripts using multiplex single nucleotide primer extension (SNuPE) assays. In this representative data set we identified only a small number of transcripts that exhibited a substantial relaxation of imprinted expression with statistical significance: Slc22a18 with 10% relaxation in the embryo after BPA treatment; Rtl1as with 11 and 16% relaxation in the lung and placenta, respectively after BPA treatment; and Rtl1 with 12% relaxation in the yolk sac after DEHP treatment. Additionally, the standard deviation of allele-specificity increased in various organs after ED treatment for several transcripts including Igf2r, Rasgrf1, Usp29, Slc38a4 and Xist. Our data suggest that the maintenance of strongly biased monoallelic expression of imprinted genes is generally insensitive to EDs in the 13.5 dpc embryo and extra-embryonic organs, but is not immune to those effects. PMID:21636974

Multiwalled carbon nanotube based molecular imprinted polymer for trace determination of 2,4-dichlorophenoxyaceticacid in natural water samples using a potentiometric method

NASA Astrophysics Data System (ADS)

Anirudhan, Thayyath S.; Alexander, Sheeba

2014-06-01

A novel potentiometric sensor based on ion imprinted polymer inclusion membrane (IPIM) was prepared from the modification of multiwalled carbon nanotube (MWCNT) based molecularly imprinted polymer for the trace determination of the pesticide 2,4-D (2,4-dichlorophenoxyacetic acid) in natural water samples. MWCNTs are initially functionalized with vinyl groups through nitric acid oxidation along with reacting by allylamine. MWCNT based imprinted polymer (MWCNT-MIP) was synthesized by means of methacrylic acid (MAA) as the monomer, trimethylol propane trimethacrylate (TRIM) as the cross linker, α,α‧-azobisisobutyronitrile (AIBN) as the initiator and 2,4-D an organochlorine pesticide molecule as the template. Organized material was characterized by means of FTIR, XRD and SEM analyses. The sensing membrane was developed by the inclusion of 2,4-D imprinted polymer materials in the polyvinyl chloride (PVC) matrix. The optimization of operational parameters normally used such as amount and nature of plasticizers sensing material, pH and response time was conducted. From the non-imprinted (NIPIM) and imprinted polymer inclusion membrane (IPIM) sensors the response behavior of 2,4-D was compared under optimum conditions. The IPIM sensor responds in the range of 1 × 10-9-1 × 10-5 M and the detection limit was found to be 1.2 × 10-9 M. The stability of MWCNT-IPIM sensor was checked by various methods and it is found to be 3 months and it can be reused many times without losing its sensitivity. For the application of sensor experiments with ground and tap water samples were performed.

Determination of a flame retardant hydrolysis product in human urine by SPE and LC-MS. Comparison of molecularly imprinted solid-phase extraction with a mixed-mode anion exchanger.

PubMed

Möller, Kristina; Crescenzi, Carlo; Nilsson, Ulrika

2004-01-01

Diphenyl phosphate is a hydrolysis product and possible metabolite of the flame retardant and plasticiser additive triphenyl phosphate. A molecularly imprinted polymer solid-phase extraction (MISPE) method for extracting diphenyl phosphate from aqueous solutions has been developed and compared with SPE using a commercially available mixed-mode anion exchanger. The imprinted polymer was prepared using 2-vinylpyridine (2-Vpy) as the functional monomer, ethylene glycol dimethacrylate (EGDMA) as the cross-linker, and a structural analogue of the analyte as the template molecule. The imprinted polymer was evaluated for use as a SPE sorbent, in tests with both aqueous standards and spiked urine samples, by comparing recovery and breakthrough data obtained using the imprinted form of the polymer and a non-imprinted form (NIP). Extraction from aqueous solutions resulted in more than 80% recovery. Adsorption by the molecularly imprinted polymer (MIP) was non-selective, but selectivity was achieved by selective desorption in the wash steps. Diphenyl phosphate could also be selectively extracted from urine samples, although the urine matrix reduced the capacity of the MISPE cartridges. Recoveries from urine extraction were higher than 70%. It was important to control pH during sample loading. The MISPE method was found to yield a less complex LC-ESI-MS chromatogram of the urine extracts compared with the mixed-mode anion-exchanger method. An LC-ESI-MS method using a Hypercarb LC column with a graphitised carbon stationary phase was also evaluated for organophosphate diesters. LC-ESI-MS using negative-ion detection in selected ion monitoring (SIM) mode was shown to be linear for diphenyl phosphate in the range 0.08-20 ng microL(-1).

Computational design and fabrication of core-shell magnetic molecularly imprinted polymer for dispersive micro-solid-phase extraction coupled with high-performance liquid chromatography for the determination of rhodamine 6G.

PubMed

Xie, Jin; Xie, Jie; Deng, Jian; Fang, Xiangfang; Zhao, Haiqing; Qian, Duo; Wang, Hongjuan

2016-06-01

A novel core-shell magnetic nano-adsorbent with surface molecularly imprinted polymer coating was fabricated and then applied to dispersive micro-solid-phase extraction followed by determination of rhodamine 6G using high-performance liquid chromatography. The molecularly imprinted polymer coating was prepared by copolymerization of dopamine and m-aminophenylboronic acid (functional monomers), in the presence of rhodamine 6G (template). The selection of the suitable functional monomers was based on the interaction between different monomers and the template using the density functional theory. The ratios of the monomers to template were further optimized by an OA9 (3(4) ) orthogonal array design. The binding performances of the adsorbent were evaluated by static, kinetic, and selective adsorption experiments. The results reveal that the adsorbent possesses remarkable affinity and binding specificity for rhodamine 6G because of the enhanced Lewis acid-base interaction between the B(Ш) embedded in the imprinted cavities and the template. The nano-adsorbent was successfully applied to dispersive micro-solid-phase extraction coupled to high-performance liquid chromatography for the trace determination of rhodamine 6G in samples with a detection limit of 2.7 nmol/L. Spiked recoveries ranged from 93.0-99.1, 89.5-92.7, and 86.9-105% in river water, matrimony vine and paprika samples, respectively, with relative standard deviations of less than 4.3%. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Fabrication of enrofloxacin imprinted organic-inorganic hybrid mesoporous sorbent from nanomagnetic polyhedral oligomeric silsesquioxanes for the selective extraction of fluoroquinolones in milk samples.

PubMed

He, Hai-Bo; Dong, Chen; Li, Bin; Dong, Jun-Ping; Bo, Tian-Yu; Wang, Tian-Lin; Yu, Qiong-Wei; Feng, Yu-Qi

2014-09-26

This paper reports a nanomagnetic polyhedral oligomeric silsesquioxanes (POSS)-directing strategy toward construction of molecularly imprinted hybrid materials for antibiotic residues determination in milk samples. The imprinted polymeric layer was facilely obtained through the copolymerization of active vinyl groups present on the nanomagnetic POSS (Fe3O4@POSS) surface and functional monomer (methacrylic acid) binding with template (enrofloxacin). Herein, the octavinyl POSS acted as not only the building blocks for hybrid rigid architectures but also the cross-linker for the formation of effective recognition sites during the imprinting process. The molecularly imprinted Fe3O4@POSS nanoparticles (Fe3O4@MI-POSS) demonstrated much higher adsorption capacity and selectivity toward enrofloxacin molecules and its analogs than the non-imprinted Fe3O4@POSS (Fe3O4@NI-POSS) materials. The imprinted particles were applied as a selective sorbent in solid-phase extraction focusing upon sample pretreatment in complex matrices prior to chromatographic analysis. The three FQs (ofloxacin, enrofloxacin, danofloxacin) could be selectively extracted from the biological matrix, while the matrix interferences were effectively eliminated simultaneously under the optimum extraction conditions. A simple, rapid and sensitive method based on the Fe3O4@MI-POSS material combined with HPLC-UV detection was then established for the simultaneous determination of three FQs from milk samples. The average recoveries of the three FQs were in the range of 75.6-108.9%. The relative standard deviations of intra- and inter-day ranging from 2.91 to 8.87% and from 3.6 to 11.5%, respectively. The limits of detections (S/N=3) were between 1.76 and 12.42 ng mL(-1). It demonstrates the effectiveness of trace analysis in complicated biological matrices utilizing magnetic separation in combination with molecularly imprinted solid-phase extraction, the rich chemistry of POSS makes it possible to be an ideal platform for generating molecular imprinted hybrid materials is also exhibited. Copyright © 2014 Elsevier B.V. All rights reserved.

Design and development of molecularly imprinted polymers for the selective extraction of deltamethrin in olive oil: An integrated computational-assisted approach.

PubMed

Martins, Nuno; Carreiro, Elisabete P; Locati, Abel; Ramalho, João P Prates; Cabrita, Maria João; Burke, Anthony J; Garcia, Raquel

2015-08-28

This work firstly addresses the design and development of molecularly imprinted systems selective for deltamethrin aiming to provide a suitable sorbent for solid phase (SPE) extraction that will be further used for the implementation of an analytical methodology for the trace analysis of the target pesticide in spiked olive oil samples. To achieve this goal, a preliminary evaluation of the molecular recognition and selectivity of the molecularly imprinted polymers has been performed. In order to investigate the complexity of the mechanistic basis for template selective recognition in these polymeric matrices, the use of a quantum chemical approach has been attempted providing new insights about the mechanisms underlying template recognition, and in particular the crucial role of the crosslinker agent and the solvent used. Thus, DFT calculations corroborate the results obtained by experimental molecular recognition assays enabling one to select the most suitable imprinting system for MISPE extraction technique which encompasses acrylamide as functional monomer and ethylene glycol dimethacrylate as crosslinker. Furthermore, an analytical methodology comprising a sample preparation step based on solid phase extraction has been implemented using this "tailor made" imprinting system as sorbent, for the selective isolation/pre-concentration of deltamethrin from olive oil samples. Molecularly imprinted solid phase extraction (MISPE) methodology was successfully applied for the clean-up of spiked olive oil samples, with recovery rates up to 94%. Copyright © 2015 Elsevier B.V. All rights reserved.

Preparation of silica-supported porous sorbent for heavy metal ions removal in wastewater treatment by organic-inorganic hybridization combined with sucrose and polyethylene glycol imprinting.

PubMed

Li, Feng; Du, Ping; Chen, Wei; Zhang, Shusheng

2007-03-07

A new porous sorbent for wastewater treatment of metal ions was synthesized by covalent grafting of molecularly imprinted organic-inorganic hybrid on silica gel. With sucrose and polyethylene glycol 4000 (PEG 4000) being synergic imprinting molecules, covalent surface coating on silica gel was achieved by using polysaccharide-incorporated sol-gel process starting from the functional biopolymer, chitosan and an inorganic epoxy-precursor, gamma-glycidoxypropyltrimethoxysiloxane (GPTMS) at room temperature. The prepared porous sorbent was characterized by using simultaneous thermogravimetry and differential scanning calorimeter (TG/DSC), scanning electron microscopy (SEM), nitrogen adsorption porosimetry measurement and X-ray diffraction (XRD). Copper ion, Cu(2+), was chosen as the model metal ion to evaluate the effectiveness of the new biosorbent in wastewater treatment. The influence of epoxy-siloxane dose, buffer pH and co-existed ions on Cu(2+) adsorption was assessed through batch experiments. The imprinted composite sorbent offered a fast kinetics for the adsorption of Cu(2+). The uptake capacity of the sorbent imprinted by two pore-building components was higher than those imprinted with only a single component. The dynamic adsorption in column underwent a good elimination of Cu(2+) in treating electric plating wastewater. The prepared composite sorbent exhibited high reusability. Easy preparation of the described porous composite sorbent, absence of organic solvents, cost-effectiveness and high stability make this approach attractive in biosorption.

Molecularly Imprinted Core-Shell CdSe@SiO2/CDs as a Ratiometric Fluorescent Probe for 4-Nitrophenol Sensing

NASA Astrophysics Data System (ADS)

Liu, Mingyue; Gao, Zhao; Yu, Yanjun; Su, Rongxin; Huang, Renliang; Qi, Wei; He, Zhimin

2018-01-01

4-Nitrophenol (4-NP) is a priority pollutant in water and is both carcinogenic and genotoxic to humans and wildlife even at very low concentrations. Thus, we herein fabricated a novel molecularly imprinted core-shell nanohybrid as a ratiometric fluorescent sensor for the highly sensitive and selective detection of 4-NP. This sensor was functioned by the transfer of fluorescence resonance energy between photoluminescent carbon dots (CDs) and 4-NP. This sensor was synthesized by linking organosilane-functionalized CDs to silica-coated CdSe quantum dots (CdSe@SiO2) via Si-O bonds. The nanohybrids were further modified by anchoring a molecularly imprinted polymer (MIP) layer on the ratiometric fluorescent sensor through a facile sol-gel polymerization method. The morphology, chemical structure, and optical properties of the resulting molecularly imprinted dual-emission fluorescent probe were characterized by transmission electron microscopy and spectroscopic analysis. The probe was then applied in the detection of 4-NP and exhibited good linearity between 0.051 and 13.7 μg/mL, in addition to a low detection limit of 0.026 μg/mL. Furthermore, the simplicity, reliability, high selectivity, and high sensitivity of the developed sensor demonstrate that the combination of MIPs and ratiometric fluorescence allows the preparation of excellent fluorescent sensors for the detection of trace or ultra-trace analytes.

The development of a new optical sensor based on the Mn doped ZnS quantum dots modified with the molecularly imprinted polymers for sensitive recognition of florfenicol

NASA Astrophysics Data System (ADS)

Sadeghi, Susan; Jahani, Moslem; Belador, Foroogh

2016-04-01

The Mn doped ZnS quantum dots (Mn:ZnS QDs) capped with the florfenicol molecularly imprinted polymer (Mn:ZnS QDs@MIP) were prepared via the sol-gel surface imprinting approach using 3-aminopropyltriethoxysilane (APTES) as the functional monomer and tetraethoxysilane (TEOS) as the cross-linker for the optosensing of the florfenicol. Transmission electron microscopy (TEM), X-ray diffractometer, IR spectroscopy, UV-Vis absorption spectrophotometry, and spectrofluorometry were used to elucidate the formation, morphology, and identification of the products. To illustrate the usefulness of the new imprinted material, the non-imprinted coated Mn:ZnS QDs (Mn:ZnS QDs@NIP) were synthesized without the presence of the florfenicol. It was revealed that the fluorescence (FL) intensity of the Mn:ZnS QDs@MIP increased with increasing the FF concentration. Under the optimal conditions, changes in the FL intensity in the presence of the target molecule showed a linear response in the concentration range of 30-700 μmol L- 1 with a detection limit of 24 μmol L- 1. The developed method was finally applied successfully to the determination of FF in different meat samples with satisfactory recoveries.

The development of a new optical sensor based on the Mn doped ZnS quantum dots modified with the molecularly imprinted polymers for sensitive recognition of florfenicol.

PubMed

Sadeghi, Susan; Jahani, Moslem; Belador, Foroogh

2016-04-15

The Mn doped ZnS quantum dots (Mn:ZnS QDs) capped with the florfenicol molecularly imprinted polymer (Mn:ZnS QDs@MIP) were prepared via the sol-gel surface imprinting approach using 3-aminopropyltriethoxysilane (APTES) as the functional monomer and tetraethoxysilane (TEOS) as the cross-linker for the optosensing of the florfenicol. Transmission electron microscopy (TEM), X-ray diffractometer, IR spectroscopy, UV-Vis absorption spectrophotometry, and spectrofluorometry were used to elucidate the formation, morphology, and identification of the products. To illustrate the usefulness of the new imprinted material, the non-imprinted coated Mn:ZnS QDs (Mn:ZnS QDs@NIP) were synthesized without the presence of the florfenicol. It was revealed that the fluorescence (FL) intensity of the Mn:ZnS QDs@MIP increased with increasing the FF concentration. Under the optimal conditions, changes in the FL intensity in the presence of the target molecule showed a linear response in the concentration range of 30-700 μmol L(-1) with a detection limit of 24 μmol L(-1). The developed method was finally applied successfully to the determination of FF in different meat samples with satisfactory recoveries. Copyright © 2016 Elsevier B.V. All rights reserved.

Preparation of magnetic imprinted graphene oxide composite for catalytic degradation of Congo red under dark ambient conditions.

PubMed

Yang, Xiaochao; You, Xiaoxiao; Zhang, Bin; Guo, Chuigen; Yu, Chaosheng

2017-10-01

Magnetic imprinted N-doped P25/Fe 3 O 4 -graphene oxide (MIGNT) was prepared with methyl orange as the dummy template and pyrrole as functional monomer for catalytic degradation of Congo red (CR). Hummers method and the hydrothermal method were used to synthesize Fe 3 O 4 -GO and N-doped P25, respectively. The results of adsorption and degradation experiments showed that the adsorption capacity and catalytic degradation ability of the imprinted composite for CR were obviously higher than those of a non-imprinted one. Moreover, the effect factors on degradation efficiency of CR, such as the initial concentration of CR, catalysis time, pH of the solution and temperature, were investigated. The MIGNT was characterized by X-ray diffraction, Fourier transform infrared spectroscopy, transmission electron microscopy, a physical property measurement system and a thermal gravimetric analyzer. The degradation products of CR were detected with high performance liquid chromatography and a mass spectrometer. The MIGNT was a brand-new imprinted composite and had high degradation efficiency for CR under dark ambient conditions. The MIGNT could be recycled conveniently, due to its magnetic property, and could be used as an effective, environmentally friendly and low-cost catalytic degradation material for the treatment of water contaminated by CR.

Zipper-like magnetic molecularly imprinted microspheres for on/off-switchable recognition and extraction of 17β-estradiol from food samples.

PubMed

Zhu, Wenting; Peng, Hailong; Luo, Mei; Yu, Ningxiang; Xiong, Hua; Wang, Ronghui; Li, Yanbin

2018-09-30

Zipper-like on/off-switchable and magnetic molecularly imprinted microspheres (SM-MIMs) were constructed using acrylamide (AAm) and 2-acrylamide-2-methyl propanesulfonic acid (AMPS) as functional monomers for 17β-estradiol (17β-E 2 ) recognition and extraction. The imprinted polymer interactions between poly(AAm) (PAAm) and poly(AMPS) (PAMPS) with on/off-switchable property to temperature, exhibited dissociation at relatively higher temperatures (such as 30 °C) and helped 17β-E 2 enter into imprinted sites, leading to higher binding capability. Conversely, the interpolymer complexes between PAAm and PAMPS formed and blocked 17β-E 2 access to imprinted sites at lower temperature (such as 20 °C). SM-MIMs were used as dispersive solid phase extraction (SPE) adsorbent with HPLC for 17β-E 2 pretreatment and detection in food samples, and low limit detection (2.52 µg L -1 ) and quantification (10.76 µg L -1 ) with higher recovery were obtained. Therefore, SM-MIMs may be a promising adsorbent for 17β-E 2 pretreatment in food samples owing to its advantages of on/off-switchable recognition, eco-friendly elution, and efficient separation. Copyright © 2018. Published by Elsevier Ltd.

Novel hybrid structure silica/CdTe/molecularly imprinted polymer: synthesis, specific recognition, and quantitative fluorescence detection of bovine hemoglobin.

PubMed

Li, Dong-Yan; He, Xi-Wen; Chen, Yang; Li, Wen-You; Zhang, Yu-Kui

2013-12-11

This work presented a novel strategy for the synthesis of the hybrid structure silica/CdTe/molecularly imprinted polymer (Si-NP/CdTe/MIP) to recognize and detect the template bovine hemoglobin (BHb). First, amino-functionalized silica nanoparticles (Si-NP) and carboxyl-terminated CdTe quantum dots (QDs) were assembled into composite nanoparticles (Si-NP/CdTe) using the EDC (1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride) chemistry. Next, Si-NP/CdTe/MIP was synthesized by anchoring molecularly imprinted polymer (MIP) layer on the surface of Si-NP/CdTe through the sol-gel technique and surface imprinting technique. The hybrid structure possessed the selectivity of molecular imprinting technique and the sensitivity of CdTe QDs as well as well-defined morphology. The binding experiment and fluorescence method demonstrated its special recognition performance toward the template BHb. Under the optimized conditions, the fluorescence intensity of the Si-NP/CdTe/MIP decreased linearly with the increase of BHb in the concentration range 0.02-2.1 μM, and the detection limit was 9.4 nM. Moreover, the reusability and reproducibility and the successful applications in practical samples indicated the synthesis of Si-NP/CdTe/MIP provided an alternative solution for special recognition and determination of protein from real samples.

Fabrication of molecularly imprinted polymer microarray on a chip by mid-infrared laser pulse initiated polymerisation.

PubMed

Henry, Olivier Y F; Piletsky, Sergey A; Cullen, David C

2008-07-15

The possibility to assess several functional polymeric materials in parallel in a microchip format could find a wide range of applications in sensing, combinatorial and high-throughput screening. However several factors, inherent to the nature of material polymerisation have limited such development. We here report an innovative fabrication approach for the elaboration of polymer microarrays bearing polymer dots typically 300 microm in diameter fabricated in situ on a glass cover slip via CO(2) laser pulse initiated polymerisation, as well as initial results on the identification of a suitable monomer composition for the molecular imprinting of dansyl-L-phenylalanine as a proof-of-concept example. A combination of methacrylic acid and 2-vinylpyridine showed the largest affinity to dansyl-L-phenylalanine which agreed with the existing literature and the results were further confirmed by HPLC. Finally, a sensor chip bearing both non-imprinted as well as imprinted polymers was also prepared in order to prove the suitability of this fabrication approach for the elaboration of MIP based sensors. The assay consisted in a simple dip-and-read step and the sensing system was able to discriminate between the l and d enantiomers of dansylphenylalanine with an imprinting factor of 1.6.

Modified Au nanoparticles-imprinted sol-gel, multiwall carbon nanotubes pencil graphite electrode used as a sensor for ranitidine determination.

PubMed

Rezaei, B; Lotfi-Forushani, H; Ensafi, A A

2014-04-01

A new, simple, and disposable molecularly imprinted electrochemical sensor for the determination of ranitidine was developed on pencil graphite electrode (PGE) via cyclic voltammetry (CV). The PGEs were coated with MWCNTs containing the carboxylic functional group (f-MWCNTs), imprinted with sol-gel and Au nanoparticle (AuNPs) layers (AuNP/MIP-sol-gel/f-MWCNT/PGE), respectively, to enhance the electrode's electrical transmission and sensitivity. The thin film of molecularly imprinted sol-gel polymers with specific binding sites for ranitidine was cast on modified PGE by electrochemical deposition. The AuNP/MIP-sol-gel/f-MWCNT/PGE thus developed was characterized by electrochemical impedance spectroscopy (EIS) and CV. The interaction between the imprinted sensor and the target molecule was also observed on the electrode by measuring the current response of 5.0mMK3[Fe(CN)6] solution as an electrochemical probe. The pick currents of ranitidine increased linearly with concentration in the ranges of 0.05 to 2.0μM, with a detection limit of (S/N=3) 0.02μM. Finally, the modified electrode was successfully employed to determine ranitidine in human urine samples. Copyright © 2014 Elsevier B.V. All rights reserved.

Boronate affinity-based surface molecularly imprinted polymers using glucose as fragment template for excellent recognition of glucosides.

PubMed

Peng, Mijun; Xiang, Haiyan; Hu, Xin; Shi, Shuyun; Chen, Xiaoqing

2016-11-25

Rapid and efficient extraction of bioactive glycosides from complex natural origins poses a difficult challenge, and then is often inherent bottleneck for their highly utilization. Herein, we propose a strategy to fabricate boronate affinity based surface molecularly imprinted polymers (MIPs) for excellent recognition of glucosides. d-glucose was used as fragment template. Boronic acid, dynamic covalent binding with d-glucose under different pH conditions, was selected as functional monomer to improve specificity. Fe 3 O 4 solid core for surface imprinting using tetraethyl orthosilicate (TEOS) as crosslinker could control imprinted shell thickness for favorable adsorption capacity and satisfactory mass transfer rate, improve hydrophilicity, separate easily by a magnet. Model adsorption studies showed that the resulting MIPs show specific recognition of glucosides. The equilibrium data fitted well to Langmuir equation and the adsorption process could be described by pseudo-second order model. Furthermore, the MIPs were successfully applied for selective extraction of three flavonoid glucosides (daidzin, glycitin, and genistin) from soybean. Results indicated that selective extraction of glucosides from complex aqueous media based on the prepared MIPs is simple, rapid, efficient and specific. Moreover, this method opens up a universal route for imprinting saccharide with cis-diol group for glycosides recognition. Copyright © 2016 Elsevier B.V. All rights reserved.

Molecular dynamics approaches to the design and synthesis of PCB targeting molecularly imprinted polymers: interference to monomer-template interactions in imprinting of 1,2,3-trichlorobenzene.

PubMed

Cleland, Dougal; Olsson, Gustaf D; Karlsson, Björn C G; Nicholls, Ian A; McCluskey, Adam

2014-02-07

The interactions between each component of the pre-polymerisation mixtures used in the synthesis of molecularly imprinted polymers (MIP) specific for 1,2,3,4,5-pentachlorobenzene (1) and 1,2,3-trichlorobenzene (2) were examined in four molecular dynamics simulations. These simulations revealed that the relative frequency of functional monomer-template (FM-T) interactions was consistent with results obtained by the synthesis and evaluation of the actual MIPs. The higher frequency of 1 interaction with trimethylstyrene (TMS; 54.7%) than 1 interaction with pentafluorostyrene (PFS; 44.7%) correlated with a higher imprinting factor (IF) of 2.1 vs. 1.7 for each functional monomer respectively. The higher frequency of PFS interactions with 2 (29.6%) than TMS interactions with 2 (1.9%) also correlated well with the observed differences in IF (3.7) of 2 MIPs imprinted using PFS as the FM than the IF (2.8) of 2 MIPs imprinted using TMS as the FM. The TMS-1 interaction dominated the molecular simulation due to high interaction energies, but the weaker TMS-2 resulted in low interaction maintenance, and thus lower IF values. Examination of the other pre-polymerisation mixture components revealed that the low levels of TMS-2 interaction was, in part, due to interference caused by the cross linker (CL) ethyleneglycol dimethylacrylate (EGDMA) interactions with TMS. The main reason was, however, attributed to MeOH interactions with TMS in both a hydrogen bond and perpendicular configuration. This positioned a MeOH directly above the π-orbital of all TMS for an average of 63.8% of MD2 creating significant interference to π-π stacking interactions between 2 and TMS. These findings are consistent with the deviation from the 'normal' molecularly imprinted polymer synthesis ratio of 1 : 4 : 20 (T : FM : CL) of 20 : 1 : 29 and 15 : 6 : 29 observed with 2 and TMS and PFS respectively. Our molecular dynamics simulations correctly predicted the high level of interference from other MIP synthesis components. The effect on PFS-1 interaction by MeOH was significantly lower and thus this system was not adversely affected.

Paradoxical leanness in the imprinting-centre deletion mouse model for Prader–Willi syndrome

PubMed Central

Golding, David M; Rees, Daniel J; Davies, Jennifer R; Relkovic, Dinko; Furby, Hannah V; Guschina, Irina A; Hopkins, Anna L; Davies, Jeffrey S; Resnick, James L; Isles, Anthony R

2016-01-01

Prader–Willi syndrome (PWS), a neurodevelopmental disorder caused by loss of paternal gene expression from 15q11–q13, is characterised by growth retardation, hyperphagia and obesity. However, as single gene mutation mouse models for this condition display an incomplete spectrum of the PWS phenotype, we have characterised the metabolic impairment in a mouse model for ‘full’ PWS, in which deletion of the imprinting centre (IC) abolishes paternal gene expression from the entire PWS cluster. We show that PWS-ICdel mice displayed postnatal growth retardation, with reduced body weight, hyperghrelinaemia and marked abdominal leanness; proportionate retroperitoneal, epididymal/omental and inguinal white adipose tissue (WAT) weights being reduced by 82%, 84% and 67%, respectively. PWS-ICdel mice also displayed a 48% reduction in proportionate interscapular brown adipose tissue (isBAT) weight with significant ‘beiging’ of abdominal WAT, and a 2°C increase in interscapular surface body temperature. Maintenance of PWS-ICdel mice under thermoneutral conditions (30°C) suppressed the thermogenic activity in PWS-ICdel males, but failed to elevate the abdominal WAT weight, possibly due to a normalisation of caloric intake. Interestingly, PWS-ICdel mice also showed exaggerated food hoarding behaviour with standard and high-fat diets, but despite becoming hyperphagic when switched to a high-fat diet, PWS-ICdel mice failed to gain weight. This evidence indicates that, unlike humans with PWS, loss of paternal gene expression from the PWS cluster in mice results in abdominal leanness. Although reduced subcutaneous insulation may lead to exaggerated heat loss and thermogenesis, abdominal leanness is likely to arise from a reduced lipid storage capacity rather than increased energy utilisation in BAT. PMID:27799465

Paradoxical leanness in the imprinting-centre deletion mouse model for Prader-Willi syndrome.

PubMed

Golding, David M; Rees, Daniel J; Davies, Jennifer R; Relkovic, Dinko; Furby, Hannah V; Guschina, Irina A; Hopkins, Anna L; Davies, Jeffrey S; Resnick, James L; Isles, Anthony R; Wells, Timothy

2017-01-01

Prader-Willi syndrome (PWS), a neurodevelopmental disorder caused by loss of paternal gene expression from 15q11-q13, is characterised by growth retardation, hyperphagia and obesity. However, as single gene mutation mouse models for this condition display an incomplete spectrum of the PWS phenotype, we have characterised the metabolic impairment in a mouse model for 'full' PWS, in which deletion of the imprinting centre (IC) abolishes paternal gene expression from the entire PWS cluster. We show that PWS-IC del mice displayed postnatal growth retardation, with reduced body weight, hyperghrelinaemia and marked abdominal leanness; proportionate retroperitoneal, epididymal/omental and inguinal white adipose tissue (WAT) weights being reduced by 82%, 84% and 67%, respectively. PWS-IC del mice also displayed a 48% reduction in proportionate interscapular brown adipose tissue (isBAT) weight with significant 'beiging' of abdominal WAT, and a 2°C increase in interscapular surface body temperature. Maintenance of PWS-IC del mice under thermoneutral conditions (30°C) suppressed the thermogenic activity in PWS-IC del males, but failed to elevate the abdominal WAT weight, possibly due to a normalisation of caloric intake. Interestingly, PWS-IC del mice also showed exaggerated food hoarding behaviour with standard and high-fat diets, but despite becoming hyperphagic when switched to a high-fat diet, PWS-IC del mice failed to gain weight. This evidence indicates that, unlike humans with PWS, loss of paternal gene expression from the PWS cluster in mice results in abdominal leanness. Although reduced subcutaneous insulation may lead to exaggerated heat loss and thermogenesis, abdominal leanness is likely to arise from a reduced lipid storage capacity rather than increased energy utilisation in BAT. © 2017 The authors.

Removal of carbamazepine and clofibric acid from water using double templates-molecularly imprinted polymers.

PubMed

Dai, Chao-meng; Zhang, Juan; Zhang, Ya-lei; Zhou, Xue-fei; Duan, Yan-ping; Liu, Shu-guang

2013-08-01

A novel double templates-molecularly imprinted polymer (MIP) was prepared by precipitation polymerization using carbamazepine (CBZ) and clofibric acid (CA) as the double templates molecular and 2-vinylpyridine as functional monomer. The equilibrium data of MIP was well described by the Freundlich isotherm model. Two kinetic models were adopted to describe the experimental data, and the pseudo second-order model well-described adsorption of CBZ and CA on the MIP. Adsorption experimental results showed that the MIP had good selectivity and adsorption capacity for CBZ and CA in the presence of competitive compounds compared with non-imprinted polymer, commercial powdered activated carbon, and C18 adsorbents. The feasibility of removing CBZ and CA from water by the MIP was demonstrated using tap water, lake water, and river water.

Preparation of monodisperse curcumin-imprinted polymer by precipitation polymerization and its application for the extraction of curcuminoids from Curcuma longa L.

PubMed

Kitabatake, Tomoko; Tabo, Hiromi; Matsunaga, Hisami; Haginaka, Jun

2013-08-01

A monodisperse molecularly imprinted polymer (MIP) for curcumin was first prepared by precipitation polymerization using methacrylamide (MAM) and 4-vinylpyridine as functional co-monomers, divinylbenzene as a crosslinker, and a mixture of acetonitrile and toluene as a porogen. The use of MAM as the co-monomer resulted in the formation of a monodisperse MIP and non-imprinted polymer (NIP). MIP and NIP, respectively, were monodispersed with a narrow particle size distribution (3.3 ± 0.09 and 3.5 ± 0.10 μm). In addition to shape recognition, hydrophobic and hydrogen-bonding interactions affected the retention and molecular-recognition of curcumin on the MIP. The MIP for curcumin could extract curcuminoids (curcumin, demethoxycurcumin, and bisdemethoxycurcumin) in Curcuma longa L.

Synthesis of molecularly imprinted organic-inorganic hybrid azobenzene materials by sol-gel for radiation induced selective recognition of 2,4-dichlorophenoxyacetic acid

NASA Astrophysics Data System (ADS)

Shuai Jiang, Guang; An Zhong, Shi; Chen, Lan; Blakey, Idriss; Whitaker, Andrew

2011-02-01

A novel photoresponsive functional monomer bearing a siloxane polymerisable group and azobenzene moieties was synthesized. This monomer was then used to prepare photoresponsive molecularly imprinted polymers (MIP), which have specific binding sites for 2,4-dichlorophenoxyacetic acid (2,4-D) through hydrogen bonding moieties. The binding affinity of the imprinted recognition sites was switchable by alternate irradiations with ultraviolet and visible light, suggesting that azobenzene groups located inside the binding sites could be used as chemical sensors and the trans-cis isomerization could regulate the affinity for the 2,4-D. In addition, the concentration of the 2,4-D was able to be quantified by monitoring the trans-to-cis photoisomerization rate constant.

Multiple Nucleosome Positioning Sites Regulate the CTCF-Mediated Insulator Function of the H19 Imprinting Control Region†

PubMed Central

Kanduri, Meena; Kanduri, Chandrasekhar; Mariano, Piero; Vostrov, Alexander A.; Quitschke, Wolfgang; Lobanenkov, Victor; Ohlsson, Rolf

2002-01-01

The 5′ region of the H19 gene harbors a methylation-sensitive chromatin insulator within an imprinting control region (ICR). Insertional mutagenesis in combination with episomal assays identified nucleosome positioning sequences (NPSs) that set the stage for the remarkably precise distribution of the four target sites for the chromatin insulator protein CTCF to nucleosome linker sequences in the H19 ICR. Changing positions of the NPSs resulted in loss of both CTCF target site occupancy and insulator function, suggesting that the NPSs optimize the fidelity of the insulator function. We propose that the NPSs ensure the fidelity of the repressed status of the maternal Igf2 allele during development by constitutively maintaining availability of the CTCF target sites. PMID:11971967

Molecularly imprinted hydrogels as functional active packaging materials.

PubMed

Benito-Peña, Elena; González-Vallejo, Victoria; Rico-Yuste, Alberto; Barbosa-Pereira, Letricia; Cruz, José Manuel; Bilbao, Ainhoa; Alvarez-Lorenzo, Carmen; Moreno-Bondi, María Cruz

2016-01-01

This paper describes the synthesis of novel molecularly imprinted hydrogels (MIHs) for the natural antioxidant ferulic acid (FA), and their application as packaging materials to prevent lipid oxidation of butter. A library of MIHs was synthesized using a synthetic surrogate of FA, 3-(4-hydroxy-3-methoxyphenyl)propionic acid (HFA), as template molecule, ethyleneglycol dimethacrylate (EDMA) as cross-linker, and 1-allylpiperazine (1-ALPP) or 2-(dimethylamino)ethyl methacrylate (DMAEMA), in combination with 2-hydroxyethyl methacrylate (HEMA) as functional monomers, at different molar concentrations. The DMAEMA/HEMA-based MIHs showed the greatest FA loading capacity, while the 1-ALLP/HEMA-based polymers exhibited the highest imprinting effect. During cold storage, FA-loaded MIHs protected butter from oxidation and led to TBARs values that were approximately half those of butter stored without protection and 25% less than those recorded for butter covered with hydrogels without FA, potentially extending the shelf life of butter. Active packaging is a new field of application for MIHs with great potential in the food industry. Copyright © 2015 Elsevier Ltd. All rights reserved.

Molecularly imprinted polymers as the extracted sorbents of clenbuterol ahead of liquid chromatographic determination*

PubMed Central

Lay, Sovichea; Yu, Hai-ning; Hu, Bao-xiang; Shen, Sheng-rong

2016-01-01

A pre-treatment methodology for clenbuterol hydrochloride (CLEN) isolation and enrichment in a complex matrix environment was developed through exploiting molecularly imprinted polymers (MIPs). CLEN-imprinted polymers were synthesized by the combined use of ally-β-cyclodextrin (ally-β-CD) and methacrylic acid (MAA), allyl-β-CD and acrylonitrile (AN), and allyl-β-CD and methyl methacrylate (MMA) as the binary functional monomers. MAA-linked allyl-β-CD MIPs (M-MAA) were characterized by Fourier transform-infrared (FT-IR) spectroscopy and a scanning electron microscope (SEM). Based upon the results, M-MAA polymers generally proved to be an excellent selective extraction compared to its references: AN-linked allyl-β-CD MIPs (M-AN) and MMA-linked allyl-β-CD MIPs (M-MMA). M-MAA polymers were eventually chosen to run through a molecularly imprinted solid-phase extraction (MISPE) micro-column to enrich CLEN residues spiked in pig livers. A high recovery was achieved, ranging from 91.03% to 96.76% with relative standard deviation (RSD) ≤4.45%. PMID:27256680

Synthesis of surface molecular imprinted polymers based on carboxyl-modified silica nanoparticles with the selective detection of dibutyl phthalate from tap water samples

NASA Astrophysics Data System (ADS)

Xu, Wanzhen; Zhang, Xiaoming; Huang, Weihong; Luan, Yu; Yang, Yanfei; Zhu, Maiyong; Yang, Wenming

2017-12-01

In this work, the molecular imprinted polymers were synthesized with the low monomer concentrations for dibutyl phthalate (DBP). The polymers were prepared over carboxyl-modified silica nanoparticle, which used methacrylic acid as the functional monomer, ethylene glycol dimethacrylate as the cross-linker agent and azoisobutyronitrile as the initiator in the process of preparation. Various measures were used to characterize the structure and morphology in order to get the optimal polymer. The characterization results show that the optimal polymer has suitable features for further adsorption process. And adsorption capacity experiments were evaluated to analyze its adsorption performance, through adsorption isotherms/kinetics, selectivity adsorption and desorption and regeneration experiments. These results showed that the molecular imprinted polymers had a short equilibrium time about 60 min and high stability with 88% after six cycles. Furthermore, the molecular imprinted polymers were successfully applied to remove dibutyl phthalate. The concentration range was 5.0-30.0 μmol L-1, and the limit of detection was 0.06 μmol L-1 in tap water samples.

Determination of phenformin hydrochloride using molecular imprinting technology coupled with flow-injection chemiluminescence.

PubMed

Liu, Zhenbo; Jia, Fengyan; Wang, Wenwen; Wang, Cuixia; Liu, Yongming

2012-01-01

A novel method was developed using molecular imprinting technology (MIT) coupled with flow-injection chemiluminescence (FI-CL) for highly sensitive detection of phenformin hydrochloride (PH). The phenformin imprinted polymer was synthesized with methacrylic acid (MAA) as a functional monomer and ethylene glycol dimethacrylate (EGDMA) as a cross-linker. Newly synthesized molecularly imprinted polymer (MIP) particles were packed into a column as a selective recognition element for determination of PH. A CL method for the determination of PH was developed based on the CL reaction of PH with N-bromosuccinimide sensitized by eosin Y in basic media. The optimization of detection conditions was investigated. The CL intensity responded linearly to the concentration of PH in the range 0.09-2.0 µg/mL, with a correlation coefficient of 0.9920. The detection limit was 0.031 µg/mL. The relative standard deviation for the determination of 1.0 µg/mL PH solution was 1.0% (n = 11). The method was applied to the determination of PH in urine samples, with satisfactory results. Copyright © 2011 John Wiley & Sons, Ltd.

Simulation, Theory, and Observations of the Spectrum of the Rayleigh-Taylor Instability due to Laser Imprint of Planar Targets

NASA Astrophysics Data System (ADS)

Keskinen, M. J.; Karasik, Max; Bates, J. W.; Schmitt, A. J.

2006-10-01

A limitation on the efficiency of high gain direct drive inertial confinement fusion is the extent of pellet disruption caused by the Rayleigh-Taylor (RT) instability. The RT instability can be seeded by pellet surface irregularities and/or laser imprint nonuniformities. It is important to characterize the evolution of the RT instability, e.g., the k-spectrum of areal mass. In this paper we study the time-dependent evolution of the spectrum of the Rayleigh-Taylor instability due to laser imprint in planar targets. This is achieved using the NRL FAST hydrodynamic simulation code together with analytical models. It is found that the optically smoothed laser imprint-driven RT spectrum develops into an inverse power law in k-space after several linear growth times. FAST simulation code results are compared with recent NRL Nike KrF laser experimental data. An analytical model, which is a function of Froude and Atwood numbers, is derived for the RT spectrum and favorably compared with both FAST simulation and Nike observations.

Differentiation-dependent Requirement of Tsix long non-coding RNA in Imprinted X-chromosome Inactivation

PubMed Central

Maclary, Emily; Buttigieg, Emily; Hinten, Michael; Gayen, Srimonta; Harris, Clair; Sarkar, Mrinal Kumar; Purushothaman, Sonya; Kalantry, Sundeep

2014-01-01

Imprinted X-inactivation is a paradigm of mammalian transgenerational epigenetic regulation resulting in silencing of genes on the paternally-inherited X-chromosome. The pre-programmed fate of the X-chromosomes is thought to be controlled in cis by the parent-of-origin-specific expression of two long non-coding RNAs, Tsix and Xist, in mice. Exclusive expression of Tsix from the maternal–X has implicated it as the instrument through which the maternal germline prevents inactivation of the maternal–X in the offspring. Here, we show that Tsix is dispensable for inhibiting Xist and X-inactivation in the early embryo and in cultured stem cells of extra-embryonic lineages. Tsix is instead required to prevent Xist expression as trophectodermal progenitor cells differentiate. Despite induction of wild-type Xist RNA and accumulation of histone H3-K27me3, many Tsix-mutant X-chromosomes fail to undergo ectopic X-inactivation. We propose a novel model of lncRNA function in imprinted X-inactivation that may also apply to other genomically imprinted loci. PMID:24979243

Synthesis and application of ion-imprinted polymer nanoparticles for the extraction and preconcentration of zinc ions.

PubMed

Roushani, Mahmoud; Abbasi, Shahryar; Khani, Hossein; Sahraei, Reza

2015-04-15

A new Zinc (II) ion-imprinted polymer (IIPs) nanoparticles was synthesised for the separation and recovery of trace Zn (II) ion from food and water sample. Zn (II) IIP was prepared by copolymerisation of methyl methacrylate (monomer) and ethylene glycol dimethacrylate (cross-linker) in the presence of Zn (II)-N,N'-o-phenylene bis (salicylideneimine) ternary complex wherein Zn (II) ion is the imprint ion and is used to form the imprinted polymer. Moreover, control polymer (NIP) particles were similarly prepared without the zinc (II) ions. The unleached and leached IIP particles were characterised by X-ray diffraction, Fourier transform infra-red spectroscopy and scanning electron microscopy. The preconcentration of Zn(2+) from aqueous solution was studied during rebinding with the leached IIP particles as a function of pH, the weight of the polymer material, the uptake and desorption times, the aqueous phase and the desorption volumes. Flame atomic absorption spectrometry was employed for determination of zinc in aqueous solution. Copyright © 2014 Elsevier Ltd. All rights reserved.

Molecular imprinting solid phase extraction for selective detection of methidathion in olive oil.

PubMed

Bakas, Idriss; Oujji, Najwa Ben; Moczko, Ewa; Istamboulie, Georges; Piletsky, Sergey; Piletska, Elena; Ait-Ichou, Ihya; Ait-Addi, Elhabib; Noguer, Thierry; Rouillon, Régis

2012-07-13

A specific adsorbent for extraction of methidathion from olive oil was developed. The design of the molecularly imprinted polymer (MIP) was based on the results of the computational screening of the library of polymerisable functional monomers. MIP was prepared by thermal polymerisation using N,N'-methylene bisacrylamide (MBAA) as a functional monomer and ethylene glycol dimethacrylate (EGDMA) as a cross-linker. The polymers based on the itaconic acid (IA), methacrylic acid (MAA) and 2-(trifluoromethyl)acryl acid (TFMAA) functional monomers and one control polymer which was made without functional monomers with cross-linker EGDMA were also synthesised and tested. The performance of each polymer was compared using corresponding imprinting factor. As it was predicted by molecular modelling the best results were obtained for the MIP prepared with MBAA. The obtained MIP was optimised in solid-phase extraction coupled with high performance liquid chromatography (MISPE-HPLC-UV) and tested for the rapid screening of methidathion in olive oil. The proposed method allowed the efficient extraction of methidathion for concentrations ranging from 0.1 to 9 mg L(-1) (r(2)=0.996). The limits of detection (LOD) and quantification (LOQ) in olive oil were 0.02 mg L(-1) and 0.1 mg L(-1), respectively. MIPs extraction was much more effective than traditional C18 reverse-phase solid phase extraction. Copyright © 2012 Elsevier B.V. All rights reserved.

Synthesis and characterisation of nano structure lead (II) ion-imprinted polymer as a new sorbent for selective extraction and preconcentration of ultra trace amounts of lead ions from vegetables, rice, and fish samples.

PubMed

Behbahani, Mohammad; Bagheri, Akbar; Taghizadeh, Mohsen; Salarian, Mani; Sadeghi, Omid; Adlnasab, Laleh; Jalali, Kobra

2013-06-01

This paper describes the preparation of new Pb(II)-imprinted polymeric particles using 2-vinylpyridine as a functional monomer, ethylene glycol dimethacrylate as the cross-linker, 2,2'- azobisisobutyronitrile as the initiator, diphenylcarbazone as the ligand, acetonitril as the solvent, and Pb(NO(3))(2) as the template ion, through bulk polymerisation technique. The imprinted lead ions were removed from the polymeric matrix using 5 mL of HCl (2 mol.L(-1)) as the eluting solvent. The lead ion concentration was determined by flame atomic absorption spectrometry. Optimum pH for maximum sorption was obtained at 6.0. Sorption and desorption of Pb(II) ions on the IIP particles were quite fast and achieved fully over 5 min. In the proposed method, the maximum sorbent capacity of the ion-imprinted polymer was calculated to be 75.4 mg g(-1). The preconcentration factor, relative standard deviation, and limit of detection of the method were found to be 245, 2.1%, and 0.42 ng mL(-1), respectively. The prepared ion-imprinted polymer particles have an increased selectivity toward Pb(II) ions over a range of competing metal ions with the same charge and similar ionic radius. This ion-imprinted polymer is an efficient solid phase for extraction and preconcentration of lead ions in complex matrixes. For proving that the proposed method is reliable, a wide range of food samples with different and complex matrixes was used. Copyright © 2012 Elsevier Ltd. All rights reserved.

Preparation of a hollow porous molecularly imprinted polymer using tetrabromobisphenol A as a dummy template and its application as SPE sorbent for determination of bisphenol A in tap water.

PubMed

Li, Jin; Zhang, Xuebin; Liu, Yuxin; Tong, Hongwu; Xu, Yeping; Liu, Shaomin

2013-12-15

In this paper, a highly selective sample cleanup procedure combing dummy molecular imprinting and solid-phase extraction (DMIP-SPE) was developed for the isolation and determination of bisphenol A (BPA) in tap water. The novel hollow porous dummy molecularly imprinted polymer (HPDMIP) was prepared adopting a sacrificial support approach, using tetrabromobisphenol A (TBBPA), whose structure was similar to that of BPA, as the dummy template and mesoporous MCM-48 nanospheres as the support. Owing to a very short distance between the binding sites and the surface, a large surface area and a good steric structure to match its imprint molecules, the maximum adsorption capacities (Qmax) of the dummy-imprinted and non-imprinted sorbents for BPA were as high as 445 and 340 μmol g(-1), respectively, and the adsorption reached about 73% of Qmax in 10 min. Meanwhile, a method was developed for the determination of BPA using HPDMIP as a solid-phase extraction enrichment sorbent coupled with HPLC. Under the optimum experimental conditions, HPDMIP exhibited satisfactory results in the enrichment and determination of BPA in tap water with a recovery rate of 95-105%, and relative standard deviations of below 6%, and it can achieve a limit of detection as low as 3 ng mL(-1). The developed extraction protocol eliminated the effect of template leakage on quantitative analysis and could be applied for the determination of BPA in complicated functional samples. © 2013 Elsevier B.V. All rights reserved.

Synthesis of surface molecular imprinted TiO2/graphene photocatalyst and its highly efficient photocatalytic degradation of target pollutant under visible light irradiation

NASA Astrophysics Data System (ADS)

Lai, Cui; Wang, Man-Man; Zeng, Guang-Ming; Liu, Yun-Guo; Huang, Dan-Lian; Zhang, Chen; Wang, Rong-Zhong; Xu, Piao; Cheng, Min; Huang, Chao; Wu, Hai-Peng; Qin, Lei

2016-12-01

The molecular imprinted TiO2/graphene photocatalyst (MIP-TiO2/GR) was successfully prepared with bisphenol A (BPA) as the template molecule (target pollutant) and o-phenylenediamine (OPDA) as functional monomers by the surface molecular imprinting method. The combination between BPA and OPDA led to the formation of the precursor, and the subsequent polymerization of OPDA initiated by ultraviolet radiation can ensure the realization of MIP-TiO2/GR. The samples were characterized by SEM, EDS, XRD, BET, UV-vis DRS and Zeta potential. In addition, adsorption capacities, adsorption selectivity and visible light photocatalytic performances of MIP-TiO2/GR and non-imprinted TiO2/graphene (NIP-TiO2/GR) were evaluated. Moreover, the effects of pH and initial BPA concentration on removal efficiency of BPA were also investigated. The results showed that MIP-TiO2/GR exhibited better adsorption capacity and adsorption selectivity towards the template molecule compared to NIP-TiO2/GR due to the imprinted cavities on the surface of MIP-TiO2/GR. Moreover, the photocatalytic activity of MIP-TiO2/GR toward the target molecules was stronger than that of NIP-TiO2/GR as a result of large adsorption capacity to target molecules and narrow band gap energy on MIP-TiO2/GR. Therefore, modifying the photocatalyst by the surface molecular imprinting is a promising method to improve the molecule recognition and photocatalytic efficiency of photocatalyst for target pollutant.

The Gpr1/Zdbf2 locus provides new paradigms for transient and dynamic genomic imprinting in mammals

PubMed Central

Duffié, Rachel; Ajjan, Sophie; Greenberg, Maxim V.; Zamudio, Natasha; Escamilla del Arenal, Martin; Iranzo, Julian; Okamoto, Ikuhiro; Barbaux, Sandrine; Fauque, Patricia; Bourc'his, Déborah

2014-01-01

Many loci maintain parent-of-origin DNA methylation only briefly after fertilization during mammalian development: Whether this form of transient genomic imprinting can impact the early embryonic transcriptome or even have life-long consequences on genome regulation and possibly phenotypes is currently unknown. Here, we report a maternal germline differentially methylated region (DMR) at the mouse Gpr1/Zdbf2 (DBF-type zinc finger-containing protein 2) locus, which controls the paternal-specific expression of long isoforms of Zdbf2 (Liz) in the early embryo. This DMR loses parental specificity by gain of DNA methylation at implantation in the embryo but is maintained in extraembryonic tissues. As a consequence of this transient, tissue-specific maternal imprinting, Liz expression is restricted to the pluripotent embryo, extraembryonic tissues, and pluripotent male germ cells. We found that Liz potentially functions as both Zdbf2-coding RNA and cis-regulatory RNA. Importantly, Liz-mediated events allow a switch from maternal to paternal imprinted DNA methylation and from Liz to canonical Zdbf2 promoter use during embryonic differentiation, which are stably maintained through somatic life and conserved in humans. The Gpr1/Zdbf2 locus lacks classical imprinting histone modifications, but analysis of mutant embryonic stem cells reveals fine-tuned regulation of Zdbf2 dosage through DNA and H3K27 methylation interplay. Together, our work underlines the developmental and evolutionary need to ensure proper Liz/Zdbf2 dosage as a driving force for dynamic genomic imprinting at the Gpr1/Zdbf2 locus. PMID:24589776

Surface-modified multifunctional MIP nanoparticles

NASA Astrophysics Data System (ADS)

Moczko, Ewa; Poma, Alessandro; Guerreiro, Antonio; Perez de Vargas Sansalvador, Isabel; Caygill, Sarah; Canfarotta, Francesco; Whitcombe, Michael J.; Piletsky, Sergey

2013-04-01

The synthesis of core-shell molecularly imprinted polymer nanoparticles (MIP NPs) has been performed using a novel solid-phase approach on immobilised templates. The same solid phase also acts as a protective functionality for high affinity binding sites during subsequent derivatisation/shell formation. This procedure allows for the rapid synthesis, controlled separation and purification of high-affinity materials, with each production cycle taking just 2 hours. The aim of this approach is to synthesise uniformly sized imprinted materials at the nanoscale which can be readily grafted with various polymers without affecting their affinity and specificity. For demonstration purposes we grafted anti-melamine MIP NPs with coatings which introduce the following surface characteristics: high polarity (PEG methacrylate); electro-activity (vinylferrocene); fluorescence (eosin acrylate); thiol groups (pentaerythritol tetrakis(3-mercaptopropionate)). The method has broad applicability and can be used to produce multifunctional imprinted nanoparticles with potential for further application in the biosensors, diagnostics and biomedical fields and as an alternative to natural receptors.The synthesis of core-shell molecularly imprinted polymer nanoparticles (MIP NPs) has been performed using a novel solid-phase approach on immobilised templates. The same solid phase also acts as a protective functionality for high affinity binding sites during subsequent derivatisation/shell formation. This procedure allows for the rapid synthesis, controlled separation and purification of high-affinity materials, with each production cycle taking just 2 hours. The aim of this approach is to synthesise uniformly sized imprinted materials at the nanoscale which can be readily grafted with various polymers without affecting their affinity and specificity. For demonstration purposes we grafted anti-melamine MIP NPs with coatings which introduce the following surface characteristics: high polarity (PEG methacrylate); electro-activity (vinylferrocene); fluorescence (eosin acrylate); thiol groups (pentaerythritol tetrakis(3-mercaptopropionate)). The method has broad applicability and can be used to produce multifunctional imprinted nanoparticles with potential for further application in the biosensors, diagnostics and biomedical fields and as an alternative to natural receptors. Electronic supplementary information (ESI) available: Details of the synthesis of eosin O-acrylate monomer and 1H-NMR spectrum of MIP NPs post-derivatised with PEG shell. See DOI: 10.1039/c3nr00354j

The Evolution of Epigenetic Regulators CTCF and BORIS/CTCFL in Amniotes

PubMed Central

Hore, Timothy A.; Deakin, Janine E.; Marshall Graves, Jennifer A.

2008-01-01

CTCF is an essential, ubiquitously expressed DNA-binding protein responsible for insulator function, nuclear architecture, and transcriptional control within vertebrates. The gene CTCF was proposed to have duplicated in early mammals, giving rise to a paralogue called “brother of regulator of imprinted sites” (BORIS or CTCFL) with DNA binding capabilities similar to CTCF, but testis-specific expression in humans and mice. CTCF and BORIS have opposite regulatory effects on human cancer-testis genes, the anti-apoptotic BAG1 gene, the insulin-like growth factor 2/H19 imprint control region (IGF2/H19 ICR), and show mutually exclusive expression in humans and mice, suggesting that they are antagonistic epigenetic regulators. We discovered orthologues of BORIS in at least two reptilian species and found traces of its sequence in the chicken genome, implying that the duplication giving rise to BORIS occurred much earlier than previously thought. We analysed the expression of CTCF and BORIS in a range of amniotes by conventional and quantitative PCR. BORIS, as well as CTCF, was found widely expressed in monotremes (platypus) and reptiles (bearded dragon), suggesting redundancy or cooperation between these genes in a common amniote ancestor. However, we discovered that BORIS expression was gonad-specific in marsupials (tammar wallaby) and eutherians (cattle), implying that a functional change occurred in BORIS during the early evolution of therian mammals. Since therians show imprinting of IGF2 but other vertebrate taxa do not, we speculate that CTCF and BORIS evolved specialised functions along with the evolution of imprinting at this and other loci, coinciding with the restriction of BORIS expression to the germline and potential antagonism with CTCF. PMID:18769711

The evolution of epigenetic regulators CTCF and BORIS/CTCFL in amniotes.

PubMed

Hore, Timothy A; Deakin, Janine E; Marshall Graves, Jennifer A

2008-08-29

CTCF is an essential, ubiquitously expressed DNA-binding protein responsible for insulator function, nuclear architecture, and transcriptional control within vertebrates. The gene CTCF was proposed to have duplicated in early mammals, giving rise to a paralogue called "brother of regulator of imprinted sites" (BORIS or CTCFL) with DNA binding capabilities similar to CTCF, but testis-specific expression in humans and mice. CTCF and BORIS have opposite regulatory effects on human cancer-testis genes, the anti-apoptotic BAG1 gene, the insulin-like growth factor 2/H19 imprint control region (IGF2/H19 ICR), and show mutually exclusive expression in humans and mice, suggesting that they are antagonistic epigenetic regulators. We discovered orthologues of BORIS in at least two reptilian species and found traces of its sequence in the chicken genome, implying that the duplication giving rise to BORIS occurred much earlier than previously thought. We analysed the expression of CTCF and BORIS in a range of amniotes by conventional and quantitative PCR. BORIS, as well as CTCF, was found widely expressed in monotremes (platypus) and reptiles (bearded dragon), suggesting redundancy or cooperation between these genes in a common amniote ancestor. However, we discovered that BORIS expression was gonad-specific in marsupials (tammar wallaby) and eutherians (cattle), implying that a functional change occurred in BORIS during the early evolution of therian mammals. Since therians show imprinting of IGF2 but other vertebrate taxa do not, we speculate that CTCF and BORIS evolved specialised functions along with the evolution of imprinting at this and other loci, coinciding with the restriction of BORIS expression to the germline and potential antagonism with CTCF.

Multiplex polymerase chain reaction on FTA cards vs. flow cytometry for B-lymphocyte clonality.

PubMed

Dictor, Michael; Skogvall, Ingela; Warenholt, Janina; Rambech, Eva

2007-01-01

Two-colour flow cytometry was compared with multiplex PCR with capillary electrophoresis for clonality determination in specific categories of B-cell lymphoma. FTA cards were evaluated for preserving DNA from node imprints and expediting molecular analysis. A single-tube multiplex PCR targeted IGH and lymphoma-specific translocations in DNA extracted from 180 frozen lymphoid tissues and DNA bound to FTA cards from 192 fresh tissues and 137 aspirates. PCR results were compared with flow cytometry in the extracted and aspirated samples. Overall, single-tube multiplex PCR sensitivity was equivalent in the sample groups (intergroup range 79%-91%). False negatives were associated with tumour origin in the follicle centre. Multiplex PCR and flow cytometry were equally sensitive and together detected 98% of B-cell lymphomas. Additional two-tube targeting of IGK suggested an overall molecular sensitivity >90%. False positive (pseudoclonal) single-tube multiplex PCR was associated with necrosis and sparse lymphocytes. Multiplex PCR using template DNA bound to an FTA card effectively detects B-lymphocyte clonality, obviates DNA extraction and refrigeration, and can be used without diminished sensitivity in fine needle aspirates or node imprints as a replacement for or complement to flow cytometry at any point in the diagnostic work-up.

Selective Solid-Phase Extraction of Zinc(II) from Environmental Water Samples Using Ion Imprinted Activated Carbon.

PubMed

Moniri, Elham; Panahi, Homayon Ahmad; Aghdam, Khaledeh; Sharif, Amir Abdollah Mehrdad

2015-01-01

A simple ion imprinted amino-functionalized sorbent was synthesized by coupling activated carbon with iminodiacetic acid, a functional compound for metal chelating, through cyanoric chloride spacer. The resulting sorbent has been characterized using FTIR spectroscopy, elemental analysis, and thermogravimetric analysis and evaluated for the preconcentration and determination of trace Zn(II) in environmental water samples. The optimum pH value for sorption of the metal ion was 6-7.5. The sorption capacity of the functionalized sorbent was 66.6 mg/g. The chelating sorbent can be reused for 10 cycles of sorption-desorption without any significant change in sorption capacity. A recovery of 100% was obtained for the metal ion with 0.5 M nitric acid as the eluent. Compared with nonimprinted polymer particles, the prepared Zn-imprinted sorbent showed high adsorption capacity, significant selectivity, and good site accessibility for Zn(II). Scatchard analysis revealed that the homogeneous binding sites were formed in the polymer. The equilibrium sorption data of Zn(II) by modified resin were analyzed by Langmuir, Freundlich, Temkin, and Redlich-Peterson models. Based on equilibrium adsorption data, the Langmuir, Freundlich, and Temkin constants were determined as 0.139, 12.82, and 2.34, respectively, at 25°C.

Genomic imprinting in Drosophila has properties of both mammalian and insect imprinting.

PubMed

Anaka, Matthew; Lynn, Audra; McGinn, Patrick; Lloyd, Vett K

2009-02-01

Genomic imprinting is a process that marks DNA, causing a change in gene or chromosome behavior, depending on the sex of the transmitting parent. In mammals, most examples of genomic imprinting affect the transcription of individual or small clusters of genes whereas in insects, genomic imprinting tends to silence entire chromosomes. This has been interpreted as evidence of independent evolutionary origins for imprinting. To investigate how these types of imprinting are related, we performed a phenotypic, molecular, and cytological analysis of an imprinted chromosome in Drosophila melanogaster. Analysis of this chromosome reveals that the imprint results in transcriptional silencing. Yet, the domain of transcriptional silencing is very large, extending at least 1.2 Mb and encompassing over 100 genes, and is associated with decreased somatic polytenization of the entire chromosome. We propose that repression of somatic replication in polytenized cells, as a secondary response to the imprint, acts to extend the size of the imprinted domain to an entire chromosome. Thus, imprinting in Drosophila has properties of both typical mammalian and insect imprinting which suggests that genomic imprinting in Drosophila and mammals is not fundamentally different; imprinting is manifest as transcriptional silencing of a few genes or silencing of an entire chromosome depending on secondary processes such as differences in gene density and polytenization.

Magnetic molecularly imprinted polymer for aspirin recognition and controlled release

NASA Astrophysics Data System (ADS)

Kan, Xianwen; Geng, Zhirong; Zhao, Yao; Wang, Zhilin; Zhu, Jun-Jie

2009-04-01

Core-shell structural magnetic molecularly imprinted polymers (magnetic MIPs) with combined properties of molecular recognition and controlled release were prepared and characterized. Magnetic MIPs were synthesized by the co-polymerization of methacrylic acid (MAA) and trimethylolpropane trimethacrylate (TRIM) around aspirin (ASP) at the surface of double-bond-functionalized Fe3O4 nanoparticles in chloroform. The obtained spherical magnetic MIPs with diameters of about 500 nm had obvious superparamagnetism and could be separated quickly by an external magnetic field. Binding experiments were carried out to evaluate the properties of magnetic MIPs and magnetic non-molecularly imprinted polymers (magnetic NIPs). The results demonstrated that the magnetic MIPs had high adsorption capacity and selectivity to ASP. Moreover, release profiles and release rate of ASP from the ASP-loaded magnetic MIPs indicated that the magnetic MIPs also had potential applications in drug controlled release.

The use of differential scanning fluorimetry in the rational design of plastic antibodies for protein targets.

PubMed

Ashley, Jon; Shukor, Yunus; Tothill, Ibtisam E

2016-11-14

The development of molecularly imprinted polymer nanoparticles (MIP-NPs), which specifically bind biomolecules, is of great interest in the area of biosensors, sample purification, therapeutic agents and biotechnology. Polymerisation techniques such as precipitation polymerisation, solid phase synthesis and core shell surface imprinting have allowed for significant improvements to be made in developing MIP-NPs which specifically recognise proteins. However, the development of MIP-NPs for protein templates (targets) still require lengthy optimisation and characterisation using different ratios of monomers in order to control their size, binding affinity and specificity. In this work we successfully demonstrated that differential scanning fluorimetry (DSF) can be used to rapidly determine the optimum imprinting conditions and monomer composition required for MIP-NP design and polymerisation. This is based on the stability of the protein template and shift in apparent melting points (Tm) upon interaction with different functional acrylic monomers. The method allows for the characterisation of molecularly imprinted nanoparticles (MIP-NPs) due to the observed differences in melting point profiles between, protein-MIP-NPs complexes, pre-polymerisation mixtures and non-imprinted nanoparticles (NIP-NPs) without the need for prior purification. The technique is simple, rapid and can be carried out on most quantitative polymerase chain reaction (qPCR) thermal cyclers which have the required filters for SYPRO © orange and could lead to the rapid development of MIPs nanoparticles for proteins.

In situ synthesis of molecularly imprinted nanoparticles in porous support membranes using high-viscosity polymerization solvents.

PubMed

Renkecz, Tibor; László, Krisztina; Horváth, Viola

2012-06-01

There is a growing need in membrane separations for novel membrane materials providing selective retention. Molecularly imprinted polymers (MIPs) are promising candidates for membrane functionalization. In this work, a novel approach is described to prepare composite membrane adsorbers incorporating molecularly imprinted microparticles or nanoparticles into commercially available macroporous filtration membranes. The polymerization is carried out in highly viscous polymerization solvents, and the particles are formed in situ in the pores of the support membrane. MIP particle composite membranes selective for terbutylazine were prepared and characterized by scanning electron microscopy and N₂ porosimetry. By varying the polymerization solvent microparticles or nanoparticles with diameters ranging from several hundred nanometers to 1 µm could be embedded into the support. The permeability of the membranes was in the range of 1000 to 20,000 Lm⁻²  hr⁻¹  bar⁻¹. The imprinted composite membranes showed high MIP/NIP (nonimprinted polymer) selectivity for the template in organic media both in equilibrium-rebinding measurements and in filtration experiments. The solid phase extraction of a mixture of the template, its analogs, and a nonrelated compound demonstrated MIP/NIP selectivity and substance selectivity of the new molecularly imprinted membrane. The synthesis technique offers a potential for the cost-effective production of selective membrane adsorbers with high capacity and high throughput. Copyright © 2012 John Wiley & Sons, Ltd.

Imprinted expression of UBE3A in non-neuronal cells from a Prader–Willi syndrome patient with an atypical deletion

PubMed Central

Martins-Taylor, Kristen; Hsiao, Jack S.; Chen, Pin-Fang; Glatt-Deeley, Heather; De Smith, Adam J.; Blakemore, Alexandra I.F.; Lalande, Marc; Chamberlain, Stormy J.

2014-01-01

Prader–Willi syndrome (PWS) and Angelman syndrome (AS) are two neurodevelopmental disorders most often caused by deletions of the same region of paternally inherited and maternally inherited human chromosome 15q, respectively. AS is a single gene disorder, caused by the loss of function of the ubiquitin ligase E3A (UBE3A) gene, while PWS is still considered a contiguous gene disorder. Rare individuals with PWS who carry atypical microdeletions on chromosome 15q have narrowed the critical region for this disorder to a 108 kb region that includes the SNORD116 snoRNA cluster and the Imprinted in Prader–Willi (IPW) non-coding RNA. Here we report the derivation of induced pluripotent stem cells (iPSCs) from a PWS patient with an atypical microdeletion that spans the PWS critical region. We show that these iPSCs express brain-specific portions of the transcripts driven by the PWS imprinting center, including the UBE3A antisense transcript (UBE3A-ATS). Furthermore, UBE3A expression is imprinted in most of these iPSCs. These data suggest that UBE3A imprinting in neurons only requires UBE3A-ATS expression, and no other neuron-specific factors. These data also suggest that a boundary element lying within the PWS critical region prevents UBE3A-ATS expression in non-neural tissues. PMID:24363065

Matrix molecularly imprinted mesoporous sol-gel sorbent for efficient solid-phase extraction of chloramphenicol from milk.

PubMed

Samanidou, Victoria; Kehagia, Maria; Kabir, Abuzar; Furton, Kenneth G

2016-03-31

Highly selective and efficient chloramphenicol imprinted sol-gel silica based inorganic polymeric sorbent (sol-gel MIP) was synthesized via matrix imprinting approach for the extraction of chloramphenicol in milk. Chloramphenicol was used as the template molecule, 3-aminopropyltriethoxysilane (3-APTES) and triethoxyphenylsilane (TEPS) as the functional precursors, tetramethyl orthosilicate (TMOS) as the cross-linker, isopropanol as the solvent/porogen, and HCl as the sol-gel catalyst. Non-imprinted sol-gel polymer (sol-gel NIP) was synthesized under identical conditions in absence of template molecules for comparison purpose. Both synthesized materials were characterized by Scanning Electron Microscopy (SEM), Fourier Transform Infrared Spectroscopy (FT-IR) and nitrogen adsorption porosimetry, which unambiguously confirmed their significant structural and morphological differences. The synthesized MIP and NIP materials were evaluated as sorbents for molecularly imprinted solid phase extraction (MISPE) of chloramphenicol in milk. The effect of critical extraction parameters (flow rate, elution solvent, sample and eluent volume, selectivity coefficient, retention capacity) was studied in terms of retention and desorption of chloramphenicol. Competition and cross reactivity tests have proved that sol-gel MIP sorbent possesses significantly higher specific retention and enrichment capacity for chloramphenicol compared to its non-imprinted analogue. The maximum imprinting factor (IF) was found as 9.7, whereas the highest adsorption capacity of chloramphenicol by sol-gel MIP was 23 mg/g. The sol-gel MIP was found to be adequately selective towards chloramphenicol to provide the necessary minimum required performance limit (MRPL) of 0.3 μg/kg set forth by European Commission after analysis by LC-MS even without requiring time consuming solvent evaporation and sample reconstitution step, often considered as an integral part in solid phase extraction work-flow. Intra and inter-assay RSD values were less than 13% and accuracy expressed as relative recovery ranged from 85 to 106%. Copyright © 2016 Elsevier B.V. All rights reserved.

Preparation and characterization of molecularly imprinted polymer for di(2-ethylhexyl) phthalate: application to sample clean-up prior to gas chromatographic determination.

PubMed

Shaikh, Huma; Memon, Najma; Khan, Hamayun; Bhanger, M I; Nizamani, S M

2012-07-20

The molecularly imprinted polymer (MIP) selective for di(2-ethylhexyl) phthalate (DEHP) an environmental endocrine disruptor was prepared by suspension polymerization using methacrylamide as functional monomer and N,N'-methylene-bis-acrylamide as cross-linker. The imprinted polymer was employed for solid-phase extraction of DEHP from water samples of environmental importance and characterized by FT-IR and SEM. The adsorption properties of the imprinted polymer were demonstrated by equilibrium rebinding experiments, Pseudo-second-order kinetic model, Sips isotherm and Scatchard analysis. The reusability of MIP was checked for at least six repeated batch adsorption cycles and the results showed almost no deterioration in the adsorption capacity. The competitive recognition studies were performed with DEHP and structurally similar compounds; dimethyl phthalate (DMP), diethyl phthalate (DEP), and dibutyl phthalate (DBP). The imprinting factor (IF) of DEHP was found to be 12.86 which was much higher than the imprinting factors (IF) of other phthalates. A method constituted by molecularly imprinted solid-phase extraction (MISPE) with GC-FID was developed for DEHP analysis in water samples under very simple conditions. Sample loading and desorption conditions were also optimized. The MISPE method's linearity ranged from 0.035 to 3.0 μg ml⁻¹ with r² = 0.9998. Intra-assay, interassay precision and accuracy ranged from 0.0168% to 1.017%, 1.130% to 4.799% and 94.98% to 99.35%, respectively. The LOD and LOQ were found to be 0.011 and 0.035 μg ml⁻¹, respectively. Synthesized MIP was employed in MISPE for cleaning up the spiked river water samples prior to gas chromatographic analysis. The river samples were found to contain DEHP in the range of 1.4 × 10⁻³ to 0.349 μg ml⁻¹. Copyright © 2012 Elsevier B.V. All rights reserved.

Sexual imprinting: what strategies should we expect to see in nature?

PubMed

Chaffee, Dalton W; Griffin, Hayes; Gilman, R Tucker

2013-12-01

Sexual imprinting occurs when juveniles learn mate preferences by observing the phenotypes of other members of their populations, and it is ubiquitous in nature. Imprinting strategies, that is which individuals and phenotypes are observed and how strong preferences become, vary among species. Imprinting can affect trait evolution and the probability of speciation, and different imprinting strategies are expected to have different effects. However, little is known about how and why different imprinting strategies evolve, or which strategies we should expect to see in nature. We used a mathematical model to study how the evolution of sexual imprinting depends on (1) imprinting costs and (2) the sex-specific fitness effects of the phenotype on which individuals imprint. We found that even small fixed costs prevent the evolution of sexual imprinting, but small relative costs do not. When imprinting does evolve, we identified the conditions under which females should evolve to imprint on their fathers, their mothers, or on other members of their populations. Our results provide testable hypotheses for empirical work and help to explain the conditions under which sexual imprinting might evolve to promote speciation. © 2013 The Author(s). Evolution © 2013 The Society for the Study of Evolution.

[Spectroscopic Study of Salbutamol Molecularly Imprinted Polymers].

PubMed

Ren, Hui-peng; Guan, Yu-yu; Dai, Rong-hua; Liu, Guo-yan; Chai, Chun-yan

2016-02-01

In order to solve the problem of on-site rapid detection of salbutamol residues in feed and animal products, and develop a new method of fast detection of salbutamol on the basis of the molecular imprinting technology, this article uses the salbutamol (SAL) working as template molecule, methacrylic acid (MAA) working as functional monomer. On this basis, a new type of core-shell type salbutamol molecularly imprinted polymers were prepared with colloidal gold particles as triggering core. Superficial characteristics of the MIPs and the related compounds were investigated by ultraviolet (UV) spectra and infrared (IR) spectra, Raman spectra, Scanning electron microscopy (SEM) respectively. The results indicated that a stable hydrogen bonding complex has been formed between the carboxyl groups of SAL and MA with a matching ratio of 1:1. The complex can be easily eluted by the reagent containing hydrogen bonding. The chemical binding constant K reaches -0.245 x 10⁶ L² · mol⁻². The possible binding sites of the hydrogen bonding was formed between the hydrogen atoms of -COOH in MA and the oxygen atoms of C==O in SAL. IR and Raman spectrum showed that, compared with MA, a significant red shift of -OH absorption peak was manifested in MIPs, which proved that SAL as template molecule occurred a specific bond between MA. Red shift of stretching vibration absorption peak of C==O was also detected in the un-eluted MIPs and obvious energy loss happened, which demonstrated a possible binding sites is SAL intramolecular of C==O atom of oxygen. If the hydrogen atoms of -COOH in MA wanted to generate hydrogen bond. However, the shapes of absorption peak of other functional groups including C==C, C==O, and -OH were very similar both in MIPs and NIPs. Specific cavities were formed after the template molecules in MIPs were removed. It was proved by the adsorption experiment that the specific sites in these cavities highly match with the chemical and space structure of SAL. Besides, colloidal gold type core-shell molecularly imprinted polymers have looser surface, more cavities in the surface compared with ordinary molecularly imprinted polymers, which increased the effective area of adsorption to target molecules. So it have better performance in adsorption. Based on the principle that these cavities can specificly recognize and combine with target molecule in the test sample, and the excellent ability of colloidal gold core-shell molecularly imprinted polymers, the development of novel methods for fast determination of SAL based on the molecular imprinting technology can be expected in the near future.

Postnatal Survival of Mice with Maternal Duplication of Distal Chromosome 7 Induced by a Igf2/H19 Imprinting Control Region Lacking Insulator Function

PubMed Central

Han, Li; Szabó, Piroska E.; Mann, Jeffrey R.

2010-01-01

The misexpressed imprinted genes causing developmental failure of mouse parthenogenones are poorly defined. To obtain further insight, we investigated misexpressions that could cause the pronounced growth deficiency and death of fetuses with maternal duplication of distal chromosome (Chr) 7 (MatDup.dist7). Their small size could involve inactivity of Igf2, encoding a growth factor, with some contribution by over-expression of Cdkn1c, encoding a negative growth regulator. Mice lacking Igf2 expression are usually viable, and MatDup.dist7 death has been attributed to the misexpression of Cdkn1c or other imprinted genes. To examine the role of misexpressions determined by two maternal copies of the Igf2/H19 imprinting control region (ICR)—a chromatin insulator, we introduced a mutant ICR (ICRΔ) into MatDup.dist7 fetuses. This activated Igf2, with correction of H19 expression and other imprinted transcripts expected. Substantial growth enhancement and full postnatal viability was obtained, demonstrating that the aberrant MatDup.dist7 phenotype is highly dependent on the presence of two unmethylated maternal Igf2/H19 ICRs. Activation of Igf2 is likely the predominant correction that rescued growth and viability. Further experiments involved the introduction of a null allele of Cdkn1c to alleviate its over-expression. Results were not consistent with the possibility that this misexpression alone, or in combination with Igf2 inactivity, mediates MatDup.dist7 death. Rather, a network of misexpressions derived from dist7 is probably involved. Our results are consistent with the idea that reduced expression of IGF2 plays a role in the aetiology of the human imprinting-related growth-deficit disorder, Silver-Russell syndrome. PMID:20062522

Background and survey of bioreplication techniques.

PubMed

Pulsifer, Drew Patrick; Lakhtakia, Akhlesh

2011-09-01

Bioreplication is the direct reproduction of a biological structure in order to realize at least one specific functionality. Current bioreplication techniques include the sol-gel technique, atomic layer deposition, physical vapor deposition, and imprint lithography and casting. The combined use of a focused ion beam and a scanning electron microscope could develop into a bioreplication technique as well. Some of these techniques are more suitable for reproducing surface features, others for bulk three-dimensional structures. Industrial upscaling appears possible only for imprint lithography and casting (which can be replaced by stamping).

A novel composite of SiO2-coated graphene oxide and molecularly imprinted polymers for electrochemical sensing dopamine.

PubMed

Zeng, Yanbo; Zhou, Ying; Kong, Lei; Zhou, Tianshu; Shi, Guoyue

2013-07-15

A novel imprinting route based on graphene oxide (GO) was proposed for preparing a composite of SiO2-coated GO and molecularly imprinted polymers (GO/SiO2-MIPs). In this route, SiO2-coated GO sheets were synthesized in a water-alcohol mixture with sol-gel technique. Prior to polymerization, the vinyl groups were introduced onto the surface of GO/SiO2 through chemical modification with γ-methacryloxypropyl trimethoxysilane (γ-MAPS), which can direct the selective polymerization on the GO/SiO2 surface. Then a novel composite of GO/SiO2-MIPs was successfully obtained by the copolymerization in presence of vinyl groups functionalized GO/SiO2, dopamine (DA), methacrylic acid and ethylene glycol dimethacrylate. The GO/SiO2-MIPs composite was characterized by FTIR, TGA, Raman spectroscopy, SEM and AFM. The properties such as special binding, adsorption dynamics and selective recognition ability using differential pulse voltammetry (DPV) were evaluated. The DPV current response of GO/SiO2-MIPs sensor was nearly 3.2 times that of the non-imprinted polymers (NIPs). In addition, the GO/SiO2-MIPs sensor could recognize DA from its relatively similar molecules of norepinephrine and epinephrine, while the sensors based on GO/SiO2-NIPs and vinyl groups functionalized GO/SiO2 did not have the ability. The GO/SiO2-MIPs sensor had a wide linear range over DA concentration from 5.0 × 10(-8) to 1.6 × 10(-4)M with a detection limit of 3.0 × 10(-8)M (S/N=3). The sensor based on this novel imprinted composite was applied to the determination of DA in injections and human urine samples with satisfactory results. Copyright © 2013 Elsevier B.V. All rights reserved.

Calorie seeking, but not hedonic response, contributes to hyperphagia in a mouse model for Prader-Willi syndrome.

PubMed

Davies, Jennifer R; Humby, Trevor; Dwyer, Dominic M; Garfield, Alastair S; Furby, Hannah; Wilkinson, Lawrence S; Wells, Timothy; Isles, Anthony R

2015-08-01

Prader-Willi syndrome (PWS) is a neurodevelopmental disorder caused by deletion or inactivation of paternally expressed imprinted genes on human chromosome 15q11-q13, the most recognised feature of which is hyperphagia. This is thought to arise as a consequence of abnormalities in both the physiological drive for food and the rewarding properties of food. Although a number of mouse models for PWS exist, the underlying variables dictating maladaptive feeding remain unknown. Here, feeding behaviour in a mouse model in which the imprinting centre (IC) of the syntenic PWS interval has been deleted (PWS(ICdel) mice) is characterised. It is demonstrated that PWS(ICdel) mice show hyperghrelinaemia and increased consumption of food both following overnight fasting and when made more palatable with sucrose. However, hyperphagia in PWS(ICdel) mice was not accompanied by any changes in reactivity to the hedonic properties of palatable food (sucrose or saccharin), as measured by lick-cluster size. Nevertheless, overall consumption by PWS(ICdel) mice for non-caloric saccharin in the licking test was significantly reduced. Combined with converging findings from a continuous reinforcement schedule, these data indicate that PWS(ICdel) mice show a marked heightened sensitivity to the calorific value of food. Overall, these data indicate that any impact of the rewarding properties of food on the hyperphagia seen in PWS(ICdel) mice is driven primarily by calorie content and is unlikely to involve hedonic processes. This has important implications for understanding the neural systems underlying the feeding phenotype of PWS and the contribution of imprinted genes to abnormal feeding behaviour more generally. © 2015 The Authors. European Journal of Neuroscience published by Federation of European Neuroscience Societies and John Wiley & Sons Ltd.

Short interspersed element (SINE) depletion and long interspersed element (LINE) abundance are not features universally required for imprinting.

PubMed

Cowley, Michael; de Burca, Anna; McCole, Ruth B; Chahal, Mandeep; Saadat, Ghazal; Oakey, Rebecca J; Schulz, Reiner

2011-04-20

Genomic imprinting is a form of gene dosage regulation in which a gene is expressed from only one of the alleles, in a manner dependent on the parent of origin. The mechanisms governing imprinted gene expression have been investigated in detail and have greatly contributed to our understanding of genome regulation in general. Both DNA sequence features, such as CpG islands, and epigenetic features, such as DNA methylation and non-coding RNAs, play important roles in achieving imprinted expression. However, the relative importance of these factors varies depending on the locus in question. Defining the minimal features that are absolutely required for imprinting would help us to understand how imprinting has evolved mechanistically. Imprinted retrogenes are a subset of imprinted loci that are relatively simple in their genomic organisation, being distinct from large imprinting clusters, and have the potential to be used as tools to address this question. Here, we compare the repeat element content of imprinted retrogene loci with non-imprinted controls that have a similar locus organisation. We observe no significant differences that are conserved between mouse and human, suggesting that the paucity of SINEs and relative abundance of LINEs at imprinted loci reported by others is not a sequence feature universally required for imprinting.

The landscape of genomic imprinting across diverse adult human tissues

PubMed Central

Baran, Yael; Subramaniam, Meena; Biton, Anne; Tukiainen, Taru; Tsang, Emily K.; Rivas, Manuel A.; Pirinen, Matti; Gutierrez-Arcelus, Maria; Smith, Kevin S.; Kukurba, Kim R.; Zhang, Rui; Eng, Celeste; Torgerson, Dara G.; Urbanek, Cydney; Li, Jin Billy; Rodriguez-Santana, Jose R.; Burchard, Esteban G.; Seibold, Max A.; MacArthur, Daniel G.; Montgomery, Stephen B.; Zaitlen, Noah A.; Lappalainen, Tuuli

2015-01-01

Genomic imprinting is an important regulatory mechanism that silences one of the parental copies of a gene. To systematically characterize this phenomenon, we analyze tissue specificity of imprinting from allelic expression data in 1582 primary tissue samples from 178 individuals from the Genotype-Tissue Expression (GTEx) project. We characterize imprinting in 42 genes, including both novel and previously identified genes. Tissue specificity of imprinting is widespread, and gender-specific effects are revealed in a small number of genes in muscle with stronger imprinting in males. IGF2 shows maternal expression in the brain instead of the canonical paternal expression elsewhere. Imprinting appears to have only a subtle impact on tissue-specific expression levels, with genes lacking a systematic expression difference between tissues with imprinted and biallelic expression. In summary, our systematic characterization of imprinting in adult tissues highlights variation in imprinting between genes, individuals, and tissues. PMID:25953952

Rapid removal of aniline from contaminated water by a novel polymeric adsorbent.

PubMed

Huang, Yunhong; Xu, Yang; He, Qinghua; Cao, Yusheng; Du, Bibai

2014-01-01

Dummy molecularly imprinted polymers (DMIPs) for aniline were synthesized by a thermal polymerization method using acrylamide as a functional monomer, ethylene dimethacrylate as a crosslinker, 2,2-azobisisobutyronitrile as a free radical initiator, acetonitrile as a porogenic solvent, and analogues of aniline, namely sulfadiazine, as the template. The DMIPs that were obtained showed a high affinity to aniline compared to non-imprinted polymers. It was proven that the DMIPs obtained using sulfadiazine as the template were much better than the molecularly imprinted polymers using aniline as the template. The results indicated that the Freundlich model was fit for the adsorption model of DMIP for aniline and the adsorption model of the DMIP for aniline was multilayer adsorption. Furthermore, the results showed that the DMIP synthesized by bulk polymerization could be used as a novel adsorbent for removal of aniline from contaminated water.

Surface-modified multifunctional MIP nanoparticles.

PubMed

Moczko, Ewa; Poma, Alessandro; Guerreiro, Antonio; Perez de Vargas Sansalvador, Isabel; Caygill, Sarah; Canfarotta, Francesco; Whitcombe, Michael J; Piletsky, Sergey

2013-05-07

The synthesis of core-shell molecularly imprinted polymer nanoparticles (MIP NPs) has been performed using a novel solid-phase approach on immobilised templates. The same solid phase also acts as a protective functionality for high affinity binding sites during subsequent derivatisation/shell formation. This procedure allows for the rapid synthesis, controlled separation and purification of high-affinity materials, with each production cycle taking just 2 hours. The aim of this approach is to synthesise uniformly sized imprinted materials at the nanoscale which can be readily grafted with various polymers without affecting their affinity and specificity. For demonstration purposes we grafted anti-melamine MIP NPs with coatings which introduce the following surface characteristics: high polarity (PEG methacrylate); electro-activity (vinylferrocene); fluorescence (eosin acrylate); thiol groups (pentaerythritol tetrakis(3-mercaptopropionate)). The method has broad applicability and can be used to produce multifunctional imprinted nanoparticles with potential for further application in the biosensors, diagnostics and biomedical fields and as an alternative to natural receptors.

Imprint control of BaTiO 3 thin films via chemically induced surface polarization pinning

DOE PAGES

Lee, Hyungwoo; Kim, Tae Heon; Patzner, Jacob J.; ...

2016-02-22

Surface-adsorbed polar molecules can significantly alter the ferroelectric properties of oxide thin films. Thus, fundamental understanding and controlling the effect of surface adsorbates are crucial for the implementation of ferroelectric thin film devices, such as ferroelectric tunnel junctions. Herein, we report an imprint control of BaTiO 3 (BTO) thin films by chemically induced surface polarization pinning in the top few atomic layers of the water-exposed BTO films. Our studies based on synchrotron X-ray scattering and coherent Bragg rod analysis demonstrate that the chemically induced surface polarization is not switchable but reduces the polarization imprint and improves the bistability of ferroelectricmore » phase in BTO tunnel junctions. Here, we conclude that the chemical treatment of ferroelectric thin films with polar molecules may serve as a simple yet powerful strategy to enhance functional properties of ferroelectric tunnel junctions for their practical applications.« less

The polarization modulation and fabrication method of two dimensional silica photonic crystals based on UV nanoimprint lithography and hot imprint

PubMed Central

Guo, Shuai; Niu, Chunhui; Liang, Liang; Chai, Ke; Jia, Yaqing; Zhao, Fangyin; Li, Ya; Zou, Bingsuo; Liu, Ruibin

2016-01-01

Based on a silica sol-gel technique, highly-structurally ordered silica photonic structures were fabricated by UV lithography and hot manual nanoimprint efforts, which makes large-scale fabrication of silica photonic crystals easy and results in low-cost. These photonic structures show perfect periodicity, smooth and flat surfaces and consistent aspect ratios, which are checked by scanning electron microscopy (SEM) and atomic force microscopy (AFM). In addition, glass substrates with imprinted photonic nanostructures show good diffraction performance in both transmission and reflection mode. Furthermore, the reflection efficiency can be enhanced by 5 nm Au nanoparticle coating, which does not affect the original imprint structure. Also the refractive index and dielectric constant of the imprinted silica is close to that of the dielectric layer in nanodevices. In addition, the polarization characteristics of the reflected light can be modulated by stripe nanostructures through changing the incident light angle. The experimental findings match with theoretical results, making silica photonic nanostructures functional integration layers in many optical or optoelectronic devices, such as LED and microlasers to enhance the optical performance and modulate polarization properties in an economical and large-scale way. PMID:27698465

Development of a fiber coating based on molecular sol-gel imprinting technology for selective solid-phase micro extraction of caffeine from human serum and determination by gas chromatography/mass spectrometry.

PubMed

Rajabi Khorrami, Afshin; Rashidpur, Amene

2012-05-21

In this work, a molecular sol-gel imprinting approach has been introduced to produce a fiber coating for selective direct immersion solid-phase microextraction (SPME) of caffeine. The polymerization mixture was composed of vinyl trimethoxysilane and methacrylic acid as vinyl sol-gel precursor and functional monomer, respectively. Caffeine was used as template molecule during polymerization process. The prepared fibers could be coupled directly to gas chromatography/mass spectrometry (GC/MS) and used for trace analysis of caffeine in a complex sample such as human serum. The parameters influencing SPME such as time, temperature and stirring speed were optimized. The prepared coating showed good selectivity towards caffeine in the presence of some structurally related compounds. Also, it offered high imprinting capability in comparison to bare fiber and non-imprinted coating. Linear range for caffeine detection was 1-80 μg mL(-1) and the limit of detection was 0.1 μg mL(-1). The intra-day and inter-day precisions of the peak areas for five replicates were 10 and 16%, respectively. Copyright © 2012 Elsevier B.V. All rights reserved.

Silencing and transcriptional properties of the imprinted Airn ncRNA are independent of the endogenous promoter

PubMed Central

Stricker, Stefan H; Steenpass, Laura; Pauler, Florian M; Santoro, Federica; Latos, Paulina A; Huang, Ru; Koerner, Martha V; Sloane, Mathew A; Warczok, Katarzyna E; Barlow, Denise P

2008-01-01

The Airn macro ncRNA is the master regulator of imprinted expression in the Igf2r imprinted gene cluster where it silences three flanking genes in cis. Airn transcription shows unusual features normally viewed as promoter specific, such as impaired post-transcriptional processing and a macro size. The Airn transcript is 108 kb long, predominantly unspliced and nuclear localized, with only a minority being variably spliced and exported. Here, we show by deletion of the Airn ncRNA promoter and replacement with a constitutive strong or weak promoter that splicing suppression and termination, as well as silencing activity, are maintained by strong Airn expression from an exogenous promoter. This indicates that all functional regions are located within the Airn transcript. DNA methylation of the maternal imprint control element (ICE) restricts Airn expression to the paternal allele and we also show that a strong active promoter is required to maintain the unmethylated state of the paternal ICE. Thus, Airn expression not only induces silencing of flanking mRNA genes but also protects the paternal copy of the ICE from de novo methylation. PMID:19008856

Cholesterol-imprinted macroporous monoliths: Preparation and characterization.

PubMed

Stepanova, Mariia А; Kinziabulatova, Lilia R; Nikitina, Anna A; Korzhikova-Vlakh, Evgenia G; Tennikova, Tatiana B

2017-11-01

The development of sorbents for selective binding of cholesterol, which is a risk factor for cardiovascular disease, has a great importance for analytical science and medicine. In this work, two series of macroporous cholesterol-imprinted monolithic sorbents differing in the composition of functional monomers (methacrylic acid, butyl methacrylate, 2-hydroxyethyl methacrylate and ethylene dimethacrylate), amount of a template (4, 6 and 8 mol%) used for molecular imprinting, as well as mean pore size were synthesized by in situ free-radical process in stainless steel housing of 50 mm × 4.6 mm i.d. All prepared materials were characterized regarding to their hydrodynamic permeability and porous properties, as well as examined by BET and SEM methods. Imprinting factors, apparent dynamic dissociation constants, the maximum binding capacity, the number of theoretical plates and the height equivalent to a theoretical palate of MIP monoliths at different mobile phase flow rates were determined. The separation of a mixture of structural analogues, namely, cholesterol and prednisolone, was demonstrated. Additionally, the possibility of using the developed monoliths for cholesterol solid-phase extraction from simulated biological solution was shown. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

The polarization modulation and fabrication method of two dimensional silica photonic crystals based on UV nanoimprint lithography and hot imprint.

PubMed

Guo, Shuai; Niu, Chunhui; Liang, Liang; Chai, Ke; Jia, Yaqing; Zhao, Fangyin; Li, Ya; Zou, Bingsuo; Liu, Ruibin

2016-10-04

Based on a silica sol-gel technique, highly-structurally ordered silica photonic structures were fabricated by UV lithography and hot manual nanoimprint efforts, which makes large-scale fabrication of silica photonic crystals easy and results in low-cost. These photonic structures show perfect periodicity, smooth and flat surfaces and consistent aspect ratios, which are checked by scanning electron microscopy (SEM) and atomic force microscopy (AFM). In addition, glass substrates with imprinted photonic nanostructures show good diffraction performance in both transmission and reflection mode. Furthermore, the reflection efficiency can be enhanced by 5 nm Au nanoparticle coating, which does not affect the original imprint structure. Also the refractive index and dielectric constant of the imprinted silica is close to that of the dielectric layer in nanodevices. In addition, the polarization characteristics of the reflected light can be modulated by stripe nanostructures through changing the incident light angle. The experimental findings match with theoretical results, making silica photonic nanostructures functional integration layers in many optical or optoelectronic devices, such as LED and microlasers to enhance the optical performance and modulate polarization properties in an economical and large-scale way.

Preparation of molecular imprinted polymers using bi-functional monomer and bi-crosslinker for solid-phase extraction of rutin.

PubMed

Zeng, Huan; Wang, Yuzhi; Liu, Xiaojie; Kong, Jinhuan; Nie, Chan

2012-05-15

Molecular imprinted polymers (MIPs) were prepared using rutin as the template, different reagents as the functional monomer and different reagents as the cross-linker by solution polymerization. Several parameters that would influence the performance of MIPs were investigated including the type of functional monomer (single or double) and cross-linker (single or double), and the molar ratio of the template, the functional monomer and the cross-linker. The optimum synthesis conditions of MIPs were found to be bi-monomers (acrylamide-co-2-vinyl pyridine, 3:1) and bi-crosslinker (ethylene glycol dimethacrylate-co-divinylbenzene, 3:1). The ratio of the template, the functional monomer and the cross-linker was found to be 1:6:20. MIPs synthesized under these conditions were filled into the cartridges as the adsorbents of solid-phase extraction (SPE). A competition test was conducted to authenticate the selectivity and the specificity of molecularly imprinted solid-phase extraction (MISPE) for rutin using the mixture solution of standard rutin and its structural analogs including quercetin, naringenin and kaempferol. Compared with purchased SPE including C(18), silica and PCX, MISPE showed better selectivity and enrichment property for rutin in the extracted solutions of Chinese medicinal plants than any others. The mean recoveries were 85.93% (RSD: 3.04%, n=3) for Saururus chinensis (Lour.) Bail and 88.61% (RSD: 3.36%, n=3) for Flos Sophorae, respectively, which indicated that the optimized rutin-MIPs possess the value of practical application. Copyright © 2012 Elsevier B.V. All rights reserved.

Beckwith-Wiedemann and IMAGe syndromes: two very different diseases caused by mutations on the same gene.

PubMed

Milani, Donatella; Pezzani, Lidia; Tabano, Silvia; Miozzo, Monica

2014-01-01

Genomic imprinting is an epigenetically regulated mechanism leading to parental-origin allele-specific expression. Beckwith-Wiedemann syndrome (BWS) is an imprinting disease related to 11p15.5 genetic and epigenetic alterations, among them loss-of-function CDKN1C mutations. Intriguing is that CDKN1C gain-of-function variations were recently found in patients with IMAGe syndrome (intrauterine growth restriction, metaphyseal dysplasia, congenital adrenal hypoplasia, and genital anomalies). BWS and IMAGe share an imprinted mode of inheritance; familial analysis demonstrated the presence of the phenotype exclusively when the mutant CDKN1C allele is inherited from the mother. Interestingly, both IMAGe and BWS are characterized by growth disturbances, although with opposite clinical phenotypes; IMAGe patients display growth restriction whereas BWS patients display overgrowth. CDKN1C codifies for CDKN1C/KIP2, a nuclear protein and potent tight-binding inhibitor of several cyclin/Cdk complexes, playing a role in maintenance of the nonproliferative state of cells. The mirror phenotype of BWS and IMAGe can be, at least in part, explained by the effect of mutations on protein functions. All the IMAGe-associated mutations are clustered in the proliferating cell nuclear antigen-binding domain of CDKN1C and cause a dramatic increase in the stability of the protein, which probably results in a functional gain of growth inhibition properties. In contrast, BWS mutations are not clustered within a single domain, are loss-of-function, and promote cell proliferation. CDKN1C is an example of allelic heterogeneity associated with opposite syndromes.

Preparation and evaluation of molecularly imprinted polymer for selective recognition and adsorption of gossypol.

PubMed

Zhi, Keke; Wang, Lulu; Zhang, Yagang; Zhang, Xuemin; Zhang, Letao; Liu, Li; Yao, Jun; Xiang, Wei

2018-03-01

Molecularly imprinted polymers (MIPs) were designed and prepared via bulk thermal polymerization with gossypol as the template molecule and dimethylaminoethyl methacrylate as the functional monomer. The morphology and microstructures of MIPs were characterized by scanning electron microscope and Brunauer-Emmett-Teller surface areas. Static adsorption tests were performed to evaluate adsorption behavior of gossypol by the MIPs. It was found that adsorption kinetics and adsorption isotherms data of MIPs for gossypol were fit well with the pseudo-second-order model and Freundlich model, respectively. Scatchard analysis showed that heterogeneous binding sites were formed in the MIPs, including lower-affinity binding sites with the maximum adsorption of 252 mg/g and higher-affinity binding sites with the maximum adsorption of 632 mg/g. Binding studies also revealed that MIPs had favorable selectivity towards gossypol compared with non-imprinted polymers. Furthermore, adsorption capacity of MIPs maintained above 90% after 5 regeneration cycles, indicating MIPs were recyclable and could be used multiple times. These results demonstrated that prepared MIPs could be a promising functional material for selective adsorption of gossypol. Copyright © 2017 John Wiley & Sons, Ltd.

Molecularly Imprinted Polymers with DNA Aptamer Fragments as Macromonomers.

PubMed

Zhang, Zijie; Liu, Juewen

2016-03-01

Molecularly imprinted polymers (MIPs) are produced in the presence of a template molecule. After removing the template, the cavity can selectively rebind the template. MIPs are attractive functional materials with a low cost and high stability, but traditional MIPs often suffer from low binding affinity. This study employs DNA aptamer fragments as macromonomers to improve MIPs. The DNA aptamer for adenosine was first split into two halves, fluorescently labeled, and copolymerized into MIPs. With a fluorescence quenching assay, the importance of imprinting was confirmed. Further studies were carried out using isothermal titration calorimetry (ITC). Compared to the mixture of the free aptamer fragments, their MIPs doubled the binding affinity. Each free aptamer fragment alone cannot bind adenosine, whereas MIPs containing each fragment are effective binders. We further shortened one of the aptamer fragments, and the DNA length was pushed to as short as six nucleotides, yielding MIPs with a dissociation constant of 27 μM adenosine. This study provides a new method for preparing functional MIP materials by combining high-affinity biopolymer fragments with low-cost synthetic monomers, allowing higher binding affinity and providing a method for signaling binding based on DNA chemistry.

Complex multicellular functions at a unicellular eukaryote level: Learning, memory, and immunity.

PubMed

Csaba, György

2017-06-01

According to experimental data, eukaryote unicellulars are able to learn, have immunity and memory. Learning is carried out in a very primitive form, and the memory is not neural but an epigenetic one. However, this epigenetic memory, which is well justified by the presence and manifestation of hormonal imprinting, is strong and permanent in the life of cell and also in its progenies. This memory is epigenetically executed by the alteration and fixation of methylation pattern of genes without changes in base sequences. The immunity of unicellulars is based on self/non-self discrimination, which leads to the destruction of non-self invaders and utilization of them as nourishment (by phagocytosis). The tools of learning, memory, and immunity of unicellulars are uniformly found in plasma membrane receptors, which formed under the effect of dynamic receptor pattern generation, suggested by Koch et al., and this is the basis of hormonal imprinting, by which the encounter between a chemical substance and the cell is specifically memorized. The receptors and imprinting are also used in the later steps of evolution up to mammals (including man) in each mentioned functions. This means that learning, memory, and immunity can be deduced to a unicellular eukaryote level.

Preparation and recognition of surface molecularly imprinted core-shell microbeads for protein in aqueous solutions

NASA Astrophysics Data System (ADS)

Lu, Yan; Yan, Chang-Ling; Gao, Shu-Yan

2009-04-01

In this paper, a surface molecular imprinting technique was reported for preparing core-shell microbeads of protein imprinting, and bovine hemoglobin or bovine serum albumin were used as model proteins for studying the imprinted core-shell microbeads. 3-Aminophenylboronic acid (APBA) was polymerized onto the surface of polystyrene microbead in the presence of the protein templates to create protein-imprinted core-shell microbeads. The various samples were characterized using scanning electron microscopy (SEM), transmission electron microscopy (TEM), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS) and Brunauer-Emmett-Teller (BET) methods. The effect of pH on rebinding of the template hemoglobin, the specific binding and selective recognition were studied for the imprinted microbeads. The results show that the bovine hemoglobin-imprinted core-shell microbeads were successfully created. The shell was a sort of imprinted thin films with porous structure and larger surface areas. The imprinted microbeads have good selectivity for templates and high stability. Due to the recognition sites locating at or closing to the surface, these imprinted microbeads have good property of mass-transport. Unfortunately, the imprint technology was not successfully applied to imprinting bovine serum albumin (BSA).

Density Functional Theory (DFT) Study of Molecularly Imprinted Polymer (MIP) Methacrylic Acid (MAA) with D-Glucose

NASA Astrophysics Data System (ADS)

Wungu, T. D. K.; Marsha, S. E.; Widayani; Suprijadi

2017-07-01

In order to find an alternative biosensor material which enables to detect the glucose level, therefore in this study, the interaction between Methacrylic Acid (MAA) based Molecularly Imprinted Polymer (MIP) with D-Glucose is investigated using the Density Functional Theory (DFT). The aim of this study is to determine whether a molecule of the MAA can be functioned as a bio-sensing of glucose. In this calculation, the Gaussian 09 with B3LYP and 631+G(d) basis sets is used to calculate all electronic properties. It is found that the interaction between a molecule of MAA and a molecule of D-Glucose was observed through the shortened distance between the two molecules. The binding energy of MAA/D-glucose and the Mulliken population analysis are investigated for checking possible interaction. From analysis, the MAA based MIP can be used as a bio-sensing material.

The effects of social rearing on preferences formed during filial imprinting and their neural correlates.

PubMed

Town, Stephen Michael

2011-08-01

Filial imprinting was originally proposed to be an irreversible process by which a young animal forms a preference for an object experienced early in life. The present study examined the effects of experience after imprinting on the stability of preferences of domestic chicks (Gallus gallus domesticus) for an imprinting stimulus by rearing imprinted chicks socially or in isolation. Chicks reared socially or in isolation retained preferences for the imprinting stimulus; however, social rearing weakened the strength of preferences. The responses of neurons within the intermediate and medial mesopallium--a forebrain region necessary for imprinting were also recorded in socially reared and isolated chicks when presented with the visual component of the imprinting stimulus and novel object. Consistent with existing findings, neurons recorded from isolated chicks responded more strongly to the imprinting stimulus than novel object. However, social rearing diminished the disparity between responses to stimuli such that neurons recorded from socially reared chicks responded similarly to the imprinting stimulus and novel object. These findings suggest that social rearing may impair the retention of preferences formed during imprinting through mechanisms involving the IMM.

NEUROBEHAVIORAL TERATOGENICITY OF SARIN IN AN AVIAN MODEL

PubMed Central

Yanai, Joseph; Pinkas, Adi; Seidler, Frederic J.; Ryde, Ian T.; Van der Zee, Eddy A.; Slotkin, Theodore A.

2009-01-01

Nerve gas organophosphates like sarin are likely to be used in urban terrorism, leading to widespread exposures of pregnant women and young children. Here, we established a model for sarin neurobehavioral teratogenicity in the developing chick so as to explore the consequences of apparently subtoxic sarin exposure and the mechanisms underlying synaptic and behavioral deficits. Chicken eggs were injected with sarin (2, 6 and 12 μg/kg) on incubation days 2 and 6, treatments that did not decrease hatching and did not evoke dysmorphology. After hatching the chicks were tested for filial imprinting and neurochemical markers known to be critical for imprinting. Imprinting was reduced at 2 and 6 μg/kg but not at the highest dose. Acetylcholinesterase and choline acetyltransferase were unaffected but sarin reduced the concentration of the high-affinity choline transporter, the rate-limiting factor in acetylcholine utilization. The concentration of PKC isoforms was assessed in the imprinting-related intermediate part of the medial hyperstriatum ventrale, the region most closely associated with cholinergic function in imprinting behavior. Sarin reduced the concentration of all isoforms (α, β, γ) with a similar, biphasic dose-response curve to that seen for behavioral performance, a relationship noted in previous work with organophosphate pesticides. Our results indicate that otherwise subtoxic exposures to sarin produce neurodevelopmental deficits; since we utilized a chick model, which is devoid of maternal confounds that are present in mammalian development, the adverse effects of sarin are mediated directly in the developing organism. PMID:19660543

Effects of an imprinting procedure on cell proliferation in the chick brain.

PubMed

Komissarova, N V; Anokhin, K V

2008-03-01

We report here studies on the effects of an imprinting procedure on cell proliferation in neonatal chicks in brain structures known to undergo plastic changes in imprinting. Proliferating cells were detected immunohistochemically on brain sections by incorporation of pre-training doses of 5-bromodeoxyuridine (BrdU) into DNA; numbers of new cells were counted in the intermediate medial mesopallium, the intermediate arcopallium, the medial part of the mesopallium and the nidopallium, the dorsocaudal nidopallium, the hippocampus, and the parahippocampal region 24 h and seven days after training. The intermediate medial mesopallium showed an increase in the number of BrdU-positive cells 24 h after training. However, at seven days post-training, the number of BrdU-containing cells decreased in the medial nidopallium and mesopallium, in the dorsocaudal nidopallium, and the right intermediate medial mesopallium. Thus, the imprinting procedure had differently directed transient and long-term influences on the genesis of new cells in the chick brain, inducing the appearance of a large number of cells in the parenchyma of the brain one day after training and decreases in the numbers of cells at later time points. This double effect may be associated with the fact that the imprinting procedure simultaneously initiates two brain processes involving the control of cell proliferation - one related to maturation of a species-specific functional system for tracking individuals of the same species and one related to remembering the characteristics of the actual parent.

Fouling Resistant CA/PVA/TiO2 Imprinted Membranes for Selective Recognition and Separation Salicylic Acid from Waste Water

PubMed Central

Yu, Xiaopeng; Mi, Xueyang; He, Zhihui; Meng, Minjia; Li, Hongji; Yan, Yongsheng

2017-01-01

Highly selective cellulose acetate (CA)/poly (vinyl alcohol) (PVA)/titanium dioxide (TiO2) imprinted membranes were synthesized by phase inversion and dip coating technique. The CA blend imprinted membrane was synthesized by phase inversion technique with CA as membrane matrix, polyethyleneimine (PEI) as the functional polymer, and the salicylic acid (SA) as the template molecule. The CA/PVA/TiO2 imprinted membranes were synthesized by dip coating of CA blend imprinted membrane in PVA and different concentration (0.05, 0.1, 0.2, 0.4 wt %) of TiO2 nanoparticles aqueous solution. The SEM analysis showed that the surface morphology of membrane was strongly influenced by the concentration of TiO2 nanoparticles. Compared with CA/PVA-TiO2(0.05, 0.1, 0.2%)-MIM, the CA/PVA-TiO2(0.4%)-MIM possessed higher membrane flux, kinetic equilibrium adsorption amount, binding capacity and better selectivity for SA. It was found that the pseudo-second-order kinetic model was studied to describe the kinetic of CA/PVA-TiO2(0.2%)-MIM judging by multiple regression analysis. Adsorption isotherm analysis indicated that the maximum adsorption capacity for SA were 24.43 mg g−1. Moreover, the selectivity coefficients of CA/PVA-TiO2 (0.2%)-MIM for SA relative to p-hydroxybenzoic acid (p-HB) and methyl salicylate (MS) were 3.87 and 3.55, respectively. PMID:28184369

Polyethyleneimine assisted-two-step polymerization to develop surface imprinted cryogels for lysozyme purification.

PubMed

Erol, Kadir; Köse, Kazım; Uzun, Lokman; Say, Rıdvan; Denizli, Adil

2016-10-01

Surface imprinting strategy is one of the promising approaches to synthesize plastic antibodies while overcoming the problems in the protein imprinting research. In this study, we focused our attentions on developing two-step polymerization to imprint on the bare surface employing polyethyleneimine (PEI) assisted-coordination of template molecules, lysozyme. For this aim, we firstly synthesized poly(2-hydroxyethyl methacrylate-glycidyl methacrylate), poly(HEMA-GMA) cryogels as a bare structure. Then, we immobilized PEI onto the cryogels through the addition reaction between GMA and PEI molecules. After that, we determined the amount of free amine (NH2) groups of PEI molecules, subsequently immobilized methacrylate functionalities onto the half of them and another half was used to chelate Cu(II) ions as a mediator between template, lysozyme and PEI groups. After the characterization of the materials developed by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and the micro-computed tomography (μCT), we optimized the lysozyme adsorption conditions from aqueous solution. Before performing lysozyme purification from chicken egg white, we evaluated the effects of pH, interaction time, the initial lysozyme concentration, temperature and ionic strength on the lysozyme adsorption. Moreover, the selectivity of surface imprinted cryogels was examined against cytochrome c and bovine serum albumin (BSA) as the competitors. Finally, the mathematical modeling, which was applied to describe the adsorption process, showed that the experimental data is very well-fitted to the Langmuir adsorption isotherm. Copyright © 2016 Elsevier B.V. All rights reserved.

Synthesis and characterization of UO(2)(2+)-ion imprinted polymer for selective extraction of UO(2)(2+).

PubMed

Singh, Dhruv K; Mishra, Shraddha

2009-06-30

Ion-imprinted polymers (IIPs) were prepared for uranyl ion (imprint ion) by formation of binary (salicylaldoxime (SALO) or 4-vinylpyridine (VP)) or ternary (salicylaldoxime and 4-vinylpyridine) complex in 2-methoxy ethanol (porogen) following copolymerization with methacrylic acid (MAA) as a functional monomer and ethylene glycol dimethacrylate (EGDMA) as crosslinking monomer using 2,2'-azobisisobutyronitrile as initiator. Control polymers (CPs) were also prepared under identical experimental conditions without using imprint ion. The above synthesized polymers were characterized by surface area measurement, microanalysis and FT-IR analysis techniques. The imprinted polymer formed with ternary complex of UO(2)(2+)-SALO-VP (1:2:2, IIP3) showed quantitative enrichment of uranyl ion from dilute aqueous solution and hence was chosen for detailed studies. The optimal pH for quantitative enrichment is 3.5-6.5. The adsorbed UO(2)(2+) was completely eluted with 10 mL of 1.0 M HCl. The retention capacity of IIP3 was found to be 0.559 mmol g(-1). Further, the distribution ratio and selectivity coefficients of uranium and other selected inorganic ions were also evaluated. Five replicate determinations of 25 microg L(-1) of uranium(VI) gave a mean absorbance of 0.032 with a relative standard deviation of 2.20%. The detection limit corresponding to three times the standard deviation of the blank was found to be 5 microg L(-1). IIP3 was tested for preconcentration of uranium(VI) from ground, river and sea water samples.

Computational design and multivariate optimization of an electrochemical metoprolol sensor based on molecular imprinting in combination with carbon nanotubes.

PubMed

Nezhadali, Azizollah; Mojarrab, Maliheh

2016-06-14

This work describes the development of an electrochemical sensor based on a new molecularly imprinted polymer for detection of metoprolol (MTP) at ultra-trace level. The polypyrrole (PPy) was electrochemically synthesized on the tip of a pencil graphite electrode (PGE) which modified whit functionalized multi-walled carbon nanotubes (MWCNTs). The fabrication process of the sensor was characterized by cyclic voltammetry (CV) and the measurement process was carried out by differential pulse voltammetry (DPV). A computational approach was used to screening functional monomers and polymerization solvent for rational design of molecularly imprinted polymer (MIP). Based on computational results, pyrrole and water were selected as functional monomer and polymerization solvent, respectively. Several significant parameters controlling the performance of the MIP sensor were examined and optimized using multivariate optimization methods such as Plackett-Burman design (PBD) and central composite design (CCD). Under the selected optimal conditions, MIP sensor was showed a linear range from 0.06 to 490 μmol L(-1) MTP, a limit of detection of 2.88 nmol L(-1), a highly reproducible response (RSD 3.9%) and a good selectivity in the presence of structurally related molecules. Furthermore, the applicability of the method was successfully tested with determination of MTP in real samples (tablet, and serum). Copyright © 2016 Elsevier B.V. All rights reserved.

Eggs, embryos and the evolution of imprinting: insights from the platypus genome.

PubMed

Renfree, Marilyn B; Papenfuss, Anthony T; Shaw, Geoff; Pask, Andrew J

2009-01-01

Genomic imprinting is widespread in eutherian and marsupial mammals. Although there have been many hypotheses to explain why genomic imprinting evolved in mammals, few have examined how it arose. The host defence hypothesis suggests that imprinting evolved from existing mechanisms within the cell that act to silence foreign DNA elements that insert into the genome. However, the changes to the mammalian genome that accompanied the evolution of imprinting have been hard to define due to the absence of large-scale genomic resources from all extant classes. The recent release of the platypus genome sequence has provided the first opportunity to make comparisons between prototherian (monotreme, which show no signs of imprinting) and therian (marsupial and eutherian, which have imprinting) mammals. We compared the distribution of repeat elements known to attract epigenetic silencing across the genome from monotremes and therian mammals, particularly focusing on the orthologous imprinted regions. Our analyses show that the platypus has significantly fewer repeats of certain classes in the regions of the genome that have become imprinted in therian mammals. The accumulation of repeats, especially long-terminal repeats and DNA elements, in therian imprinted genes and gene clusters therefore appears to be coincident with, and may have been a potential driving force in, the development of mammalian genomic imprinting. Comparative platypus genome analyses of orthologous imprinted regions have provided strong support for the host defence hypothesis to explain the origin of imprinting.

A 17-billion-solar-mass black hole in a group galaxy with a diffuse core.

PubMed

Thomas, Jens; Ma, Chung-Pei; McConnell, Nicholas J; Greene, Jenny E; Blakeslee, John P; Janish, Ryan

2016-04-21

Quasars are associated with and powered by the accretion of material onto massive black holes; the detection of highly luminous quasars with redshifts greater than z = 6 suggests that black holes of up to ten billion solar masses already existed 13 billion years ago. Two possible present-day 'dormant' descendants of this population of 'active' black holes have been found in the galaxies NGC 3842 and NGC 4889 at the centres of the Leo and Coma galaxy clusters, which together form the central region of the Great Wall--the largest local structure of galaxies. The most luminous quasars, however, are not confined to such high-density regions of the early Universe; yet dormant black holes of this high mass have not yet been found outside of modern-day rich clusters. Here we report observations of the stellar velocity distribution in the galaxy NGC 1600--a relatively isolated elliptical galaxy near the centre of a galaxy group at a distance of 64 megaparsecs from Earth. We use orbit superposition models to determine that the black hole at the centre of NGC 1600 has a mass of 17 billion solar masses. The spatial distribution of stars near the centre of NGC 1600 is rather diffuse. We find that the region of depleted stellar density in the cores of massive elliptical galaxies extends over the same radius as the gravitational sphere of influence of the central black holes, and interpret this as the dynamical imprint of the black holes.

Cost-effective imprinting combining macromolecular crowding and a dummy template for the fast purification of punicalagin from pomegranate husk extract.

PubMed

Sun, Guang-Ying; Wang, Chao; Luo, Yu-Qin; Zhao, Yong-Xin; Yang, Jian; Liu, Zhao-Sheng; Aisa, Haji Akber

2016-05-01

The combination of molecular crowding and virtual imprinting was employed to develop a cost-effective method to prepare molecularly imprinted polymers. By using linear polymer polystyrene as a macromolecular crowding agent, an imprinted polymer recognizable to punicalagin had been successfully synthesized with punicalin as the dummy template. The resulting punicalin-imprinted polymer presented a remarkable selectivity to punicalagin with an imprinting factor of 3.17 even at extremely low consumption of the template (template/monomer ratio of 1:782). In contrast, the imprinted polymer synthesized without crowding agent, did not show any imprinting effect at so low template amount. The imprinted polymers made by combination of molecular crowding and virtual imprinting can be utilized for the fast separation of punicalagin from pomegranate husk extract after optimizing the protocol of solid-phase extraction with the recovery of 85.3 ± 1.2%. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

The landscape of genomic imprinting across diverse adult human tissues.

PubMed

Baran, Yael; Subramaniam, Meena; Biton, Anne; Tukiainen, Taru; Tsang, Emily K; Rivas, Manuel A; Pirinen, Matti; Gutierrez-Arcelus, Maria; Smith, Kevin S; Kukurba, Kim R; Zhang, Rui; Eng, Celeste; Torgerson, Dara G; Urbanek, Cydney; Li, Jin Billy; Rodriguez-Santana, Jose R; Burchard, Esteban G; Seibold, Max A; MacArthur, Daniel G; Montgomery, Stephen B; Zaitlen, Noah A; Lappalainen, Tuuli

2015-07-01

Genomic imprinting is an important regulatory mechanism that silences one of the parental copies of a gene. To systematically characterize this phenomenon, we analyze tissue specificity of imprinting from allelic expression data in 1582 primary tissue samples from 178 individuals from the Genotype-Tissue Expression (GTEx) project. We characterize imprinting in 42 genes, including both novel and previously identified genes. Tissue specificity of imprinting is widespread, and gender-specific effects are revealed in a small number of genes in muscle with stronger imprinting in males. IGF2 shows maternal expression in the brain instead of the canonical paternal expression elsewhere. Imprinting appears to have only a subtle impact on tissue-specific expression levels, with genes lacking a systematic expression difference between tissues with imprinted and biallelic expression. In summary, our systematic characterization of imprinting in adult tissues highlights variation in imprinting between genes, individuals, and tissues. © 2015 Baran et al.; Published by Cold Spring Harbor Laboratory Press.

Global survey of genomic imprinting by transcriptome sequencing.

PubMed

Babak, Tomas; Deveale, Brian; Armour, Christopher; Raymond, Christopher; Cleary, Michele A; van der Kooy, Derek; Johnson, Jason M; Lim, Lee P

2008-11-25

Genomic imprinting restricts gene expression to a paternal or maternal allele. To date, approximately 90 imprinted transcripts have been identified in mouse, of which the majority were detected after intense interrogation of clusters of imprinted genes identified by phenotype-driven assays in mice with uniparental disomies [1]. Here we use selective priming and parallel sequencing to measure allelic bias in whole transcriptomes. By distinguishing parent-of-origin bias from strain-specific bias in embryos derived from a reciprocal cross of mice, we constructed a genome-wide map of imprinted transcription. This map was able to objectively locate over 80% of known imprinted loci and allowed the detection and confirmation of six novel imprinted genes. Even in the intensely studied embryonic day 9.5 developmental stage that we analyzed, more than half of all imprinted single-nucleotide polymorphisms did not overlap previously discovered imprinted transcripts; a large fraction of these represent novel noncoding RNAs within known imprinted loci. For example, a previously unnoticed, maternally expressed antisense transcript was mapped within the Grb10 locus. This study demonstrates the feasibility of using transcriptome sequencing for mapping of imprinted gene expression in physiologically normal animals. Such an approach will allow researchers to study imprinting without restricting themselves to individual loci or specific transcripts.

Multifunctional Nano-engineered Polymer Surfaces with Enhanced Mechanical Resistance and Superhydrophobicity

NASA Astrophysics Data System (ADS)

Hernández, Jaime J.; Monclús, Miguel A.; Navarro-Baena, Iván; Viela, Felipe; Molina-Aldareguia, Jon M.; Rodríguez, Isabel

2017-03-01

This paper presents a multifunctional polymer surface that provides superhydrophobicity and self-cleaning functions together with an enhancement in mechanical and electrical performance. These functionalities are produced by nanoimprinting high aspect ratio pillar arrays on polymeric matrix incorporating functional reinforcing elements. Two distinct matrix-filler systems are investigated specifically, Carbon Nanotube reinforced Polystyrene (CNT-PS) and Reduced Graphene Oxide reinforced Polyvinylidene Difluoride (RGO-PVDF). Mechanical characterization of the topographies by quantitative nanoindentation and nanoscratch tests are performed to evidence a considerable increase in stiffness, Young’s modulus and critical failure load with respect to the pristine polymers. The improvement on the mechanical properties is rationalized in terms of effective dispersion and penetration of the fillers into the imprinted structures as determined by confocal Raman and SEM studies. In addition, an increase in the degree of crystallization for the PVDF-RGO imprinted nanocomposite possibly accounts for the larger enhancement observed. Improvement of the mechanical ruggedness of functional textured surfaces with appropriate fillers will enable the implementation of multifunctional nanotextured materials in real applications.

Phagocytosis imprints heterogeneity in tissue-resident macrophages

PubMed Central

A-Gonzalez, Noelia; Quintana, Juan A.; Mazariegos, Marina; González de la Aleja, Arturo; Nicolás-Ávila, José A.; Crainiciuc, Georgiana; Rothlin, Carla V.; Peinado, Héctor; Castrillo, Antonio

2017-01-01

Tissue-resident macrophages display varying phenotypic and functional properties that are largely specified by their local environment. One of these functions, phagocytosis, mediates the natural disposal of billions of cells, but its mechanisms and consequences within living tissues are poorly defined. Using a parabiosis-based strategy, we identified and isolated macrophages from multiple tissues as they phagocytosed blood-borne cellular material. Phagocytosis was circadianally regulated and mediated by distinct repertoires of receptors, opsonins, and transcription factors in macrophages from each tissue. Although the tissue of residence defined the core signature of macrophages, phagocytosis imprinted a distinct antiinflammatory profile. Phagocytic macrophages expressed CD206, displayed blunted expression of Il1b, and supported tissue homeostasis. Thus, phagocytosis is a source of macrophage heterogeneity that acts together with tissue-derived factors to preserve homeostasis. PMID:28432199

Polarization imprint effects on the photovoltaic effect in Pb(Zr,Ti)O3 thin films

NASA Astrophysics Data System (ADS)

Tan, Zhengwei; Tian, Junjiang; Fan, Zhen; Lu, Zengxing; Zhang, Luyong; Zheng, Dongfeng; Wang, Yadong; Chen, Deyang; Qin, Minghui; Zeng, Min; Lu, Xubing; Gao, Xingsen; Liu, Jun-Ming

2018-04-01

The polarization imprint along with the photovoltaic (PV) effect has been studied in Pt/Pb(Zr0.3Ti0.7)O3/SrRuO3 ferroelectric capacitors. It is shown that the positive DC poling induces the imprint with a downward direction whereas the negative DC poling suppresses the imprint (i.e., rejuvenation). In the polarization up state, the imprinted capacitor exhibits degraded PV properties compared with the rejuvenated one. This may be because the imprint reduces the number of upward domains, thus lowering the driving force for the PV effect. In the polarization down state, however, the rejuvenated capacitor enters the imprinted state spontaneously. This rejuvenation-to-imprint transition can be further aggravated by applying positive voltages and ultraviolet illumination. It is proposed that the domain pinning/depinning, which are associated with the oxygen vacancies and trapped electrons modulated by polarization, voltage, and illumination, may be responsible for the polarization imprint and rejuvenation. Our study therefore sheds light on the correlation between the polarization imprint and the PV effect in the ferroelectrics and also provides some viable suggestions to address the imprint-induced degradation of PV performance.

Molecularly Imprinted Polymers Chitosan-Glutaraldehyde for Monosodium Glutamate

NASA Astrophysics Data System (ADS)

Mulyasuryani, Ani; Haryanto, Edi; Sulistyarti, Hermin; Rumhayati, Barlah

2018-01-01

Chitosan has been used as a functional monomer in the synthesis of molecularly imprinted polymers (MIP) for monosodium glutamate (MSG). MIP is made from a mixture of 5 g chitosan, 50 mg glutaraldehyde and 2 g MSG, MIP is formed as flakes and beads. MIPs are identified by the FTIR spectrum, SEM image and their adsorption capabilities. MIP flakes and beads have no structural differences if they are based on FTIR or SEM spectra, but MIP adsorption capacity of beads higher than flakes. Adsorption capacity of MIP flakes is 548 mg/g and MIP beads 627 mg/g.

Novel deletion of the E3A ubiquitin protein ligase gene detected by multiplex ligation-dependent probe amplification in a patient with Angelman syndrome

PubMed Central

Calì, Francesco; Ragalmuto, Alda; Chiavetta, Valeria; Calabrese, Giuseppe; Fichera, Marco; Vinci, Mirella; Ruggeri, Giuseppa; Schinocca, Pietro; Sturnio, Maurizio; Romano, Salvatore; Elia, Maurizio

2010-01-01

Angelman syndrome (AS) is a severe neurobehavioural disorder caused by failure of expression of the maternal copy of the imprinted domain located on 15q11-q13. There are different mechanisms leading to AS: maternal microdeletion, uniparental disomy, defects in a putative imprinting centre, mutations of the E3 ubiquitin protein ligase (UBE3A) gene. However, some of suspected cases of AS are still scored negative to all the latter mutations. Recently, it has been shown that a proportion of negative cases bear large deletions overlapping one or more exons of the UBE3A gene. These deletions are difficult to detect by conventional gene-scanning methods due to the masking effect by the non-deleted allele. In this study, we have used for the first time multiplex ligation-dependent probe amplification (MLPA) and comparative multiplex dosage analysis (CMDA) to search for large deletions affecting the UBE3A gene. Using this approach, we identified a novel causative deletion involving exon 8 in an affected sibling. Based on our results, we propose the use of MLPA as a fast, accurate and inexpensive test to detect large deletions in the UBE3A gene in a small but significant percentage of AS patients. PMID:21072004

21 CFR 206.10 - Code imprint required.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 4 2010-04-01 2010-04-01 false Code imprint required. 206.10 Section 206.10 Food...: GENERAL IMPRINTING OF SOLID ORAL DOSAGE FORM DRUG PRODUCTS FOR HUMAN USE § 206.10 Code imprint required... imprint that, in conjunction with the product's size, shape, and color, permits the unique identification...

Preparation of clenbuterol imprinted monolithic polymer with hydrophilic outer layers by reversible addition-fragmentation chain transfer radical polymerization and its application in the clenbuterol determination from human serum by on-line solid-phase extraction/HPLC analysis.

PubMed

Li, Xiaobing; Zhou, Man; Turson, Mamat; Lin, Shen; Jiang, Ping; Dong, Xiangchao

2013-05-21

A novel imprinted monolithic material with the ability of protein exclusion was developed for the selective extraction of clenbuterol (CLE) from biological samples by direct injection in the HPLC analysis. The material has an imprinted inner structure and hydrophilic outer layer. The reversible addition-fragmentation chain transfer (RAFT) polymerization was employed in the material preparation by a two-step procedure. In the first step, clenbuterol imprinted monolithic polymer was synthesized by combining the molecular imprinting and the RAFT polymerization techniques. The resulting monolithic polymer has a RAFT chain transfer agent (trithioester groups) in its structure, which was used to graft poly(glycerol mono-methacrylate) [pGMMA] in the second step by post-RAFT polymerization. The hydrophilic pGMMA layers grafted on the surface of the imprinted monolith created barriers for protein diffusion. More than 90% of bovine serum albumin can be excluded from the pGMMA coated monolithic column. Meanwhile the clenbuterol was retained selectively with a large retention factor. The result indicated that the column, denoted as RA-MIM, has both the merits of a molecularly imprinted polymer and restricted access material. By using RA-MIM as the solid-phase extraction pre-column, an on-line column-switching HPLC method for the determination of clenbuterol in human serum has been established and validated. The recoveries of clenbuterol from the serum were 87.3-96.9% in the spiked level 2-1000 ng mL(-1). Both good linearity (R = 0.999) and acceptable reproducibility (RSD < 7.0%) were obtained. The limit of detection and the limit of quantitation were 0.7 ng mL(-1) and 2.0 ng mL(-1) respectively, which is sensitive in terms of UV detection. The results have demonstrated that the RAFT polymerization can be used to synthesize bi-functional monolithic columns by using its living reaction property. The resulting RA-MIM in this research can be used for efficient clenbuterol determination by HPLC from biological samples.

Genomic Imprinting in Mammals

PubMed Central

Barlow, Denise P.

2014-01-01

Genomic imprinting affects a subset of genes in mammals and results in a monoallelic, parental-specific expression pattern. Most of these genes are located in clusters that are regulated through the use of insulators or long noncoding RNAs (lncRNAs). To distinguish the parental alleles, imprinted genes are epigenetically marked in gametes at imprinting control elements through the use of DNA methylation at the very least. Imprinted gene expression is subsequently conferred through lncRNAs, histone modifications, insulators, and higher-order chromatin structure. Such imprints are maintained after fertilization through these mechanisms despite extensive reprogramming of the mammalian genome. Genomic imprinting is an excellent model for understanding mammalian epigenetic regulation. PMID:24492710

Identification of an Imprinted Gene Cluster in the X-Inactivation Center

PubMed Central

Kobayashi, Shin; Totoki, Yasushi; Soma, Miki; Matsumoto, Kazuya; Fujihara, Yoshitaka; Toyoda, Atsushi; Sakaki, Yoshiyuki; Okabe, Masaru; Ishino, Fumitoshi

2013-01-01

Mammalian development is strongly influenced by the epigenetic phenomenon called genomic imprinting, in which either the paternal or the maternal allele of imprinted genes is expressed. Paternally expressed Xist, an imprinted gene, has been considered as a single cis-acting factor to inactivate the paternally inherited X chromosome (Xp) in preimplantation mouse embryos. This means that X-chromosome inactivation also entails gene imprinting at a very early developmental stage. However, the precise mechanism of imprinted X-chromosome inactivation remains unknown and there is little information about imprinted genes on X chromosomes. In this study, we examined whether there are other imprinted genes than Xist expressed from the inactive paternal X chromosome and expressed in female embryos at the preimplantation stage. We focused on small RNAs and compared their expression patterns between sexes by tagging the female X chromosome with green fluorescent protein. As a result, we identified two micro (mi)RNAs–miR-374-5p and miR-421-3p–mapped adjacent to Xist that were predominantly expressed in female blastocysts. Allelic expression analysis revealed that these miRNAs were indeed imprinted and expressed from the Xp. Further analysis of the imprinting status of adjacent locus led to the discovery of a large cluster of imprinted genes expressed from the Xp: Jpx, Ftx and Zcchc13. To our knowledge, this is the first identified cluster of imprinted genes in the cis-acting regulatory region termed the X-inactivation center. This finding may help in understanding the molecular mechanisms regulating imprinted X-chromosome inactivation during early mammalian development. PMID:23940725

Identification of an imprinted gene cluster in the X-inactivation center.

PubMed

Kobayashi, Shin; Totoki, Yasushi; Soma, Miki; Matsumoto, Kazuya; Fujihara, Yoshitaka; Toyoda, Atsushi; Sakaki, Yoshiyuki; Okabe, Masaru; Ishino, Fumitoshi

2013-01-01

Mammalian development is strongly influenced by the epigenetic phenomenon called genomic imprinting, in which either the paternal or the maternal allele of imprinted genes is expressed. Paternally expressed Xist, an imprinted gene, has been considered as a single cis-acting factor to inactivate the paternally inherited X chromosome (Xp) in preimplantation mouse embryos. This means that X-chromosome inactivation also entails gene imprinting at a very early developmental stage. However, the precise mechanism of imprinted X-chromosome inactivation remains unknown and there is little information about imprinted genes on X chromosomes. In this study, we examined whether there are other imprinted genes than Xist expressed from the inactive paternal X chromosome and expressed in female embryos at the preimplantation stage. We focused on small RNAs and compared their expression patterns between sexes by tagging the female X chromosome with green fluorescent protein. As a result, we identified two micro (mi)RNAs-miR-374-5p and miR-421-3p-mapped adjacent to Xist that were predominantly expressed in female blastocysts. Allelic expression analysis revealed that these miRNAs were indeed imprinted and expressed from the Xp. Further analysis of the imprinting status of adjacent locus led to the discovery of a large cluster of imprinted genes expressed from the Xp: Jpx, Ftx and Zcchc13. To our knowledge, this is the first identified cluster of imprinted genes in the cis-acting regulatory region termed the X-inactivation center. This finding may help in understanding the molecular mechanisms regulating imprinted X-chromosome inactivation during early mammalian development.

Synthesis and application of ion-imprinted polymer nanoparticles for the extraction and preconcentration of copper ions in environmental water samples.

PubMed

Roushani, Mahmoud; Abbasi, Shahryar; Khani, Hossein

2015-04-01

Novel Cu(II) ion-imprinted polymers (Cu-IIP) nanoparticles were prepared by using Cu(II) ion-thiosemicarbazide complex as the template molecule and methacrylic acid, ethylene glycol dimethacrylate (EGDMA), and 2,2'azobisisobutyronitrile (AIBN) as the functional monomer, cross-linker, and the radical initiator, respectively. The synthesized polymer nanoparticles were characterized by using infrared spectroscopy (IR), thermo gravimetric analysis (TGA), X-ray diffraction (XRD), and scanning electron microscopic (SEM) techniques. Some parameters such as pH, weight of the polymer, adsorption time, elution time, eluent type, and eluent volume which affect the extraction efficiency of the polymer were studied. In the proposed method, the maximum sorbent capacity of the ion-imprinted polymer was calculated to be 38.8 mg g(-1). The preconcentration factor, relative standard deviation, and limit of detection of the method were found to be 80, 1.7%, and 0.003 μg mL(-1), respectively. The prepared ion-imprinted polymer nanoparticles have an increased selectivity toward Cu(II) ions over a range of competing metal ions with the same charge and similar ionic radius. The method was applied to the determination of ultra trace levels of Cu2+ in environmental water samples with satisfactory results.

Molecularly imprinted polymer cartridges coupled on-line with high performance liquid chromatography for simple and rapid analysis of dextromethorphan in human plasma samples.

PubMed

Moein, Mohammad Mahdi; Javanbakht, Mehran; Akbari-Adergani, Behrouz

2011-04-01

In this paper, a novel method is described for automated determination of dextromethorphan in biological fluids using molecularly imprinted solid-phase extraction (MISPE) as a sample clean-up technique combined with high performance liquid chromatography (HPLC). The water-compatible molecularly imprinted polymers (MIPs) were prepared using methacrylic acid as functional monomer, ethylene glycol dimethacrylate as cross-linker, chloroform as porogen and dextromethorphan as template molecule. These imprinted polymers were used as solid-phase extraction sorbent for the extraction of dextromethorphan from human plasma samples. Various parameters affecting the extraction efficiency of the MIP cartridges were evaluated. The high selectivity of the sorbent coupled to the high performance liquid chromatographic system permitted a simple and rapid analysis of this drug in plasma samples with limits of detection (LOD) and quantification (LOQ) of 0.12 ng/mL and 0.35 ng/mL, respectively. The MIP selectivity was evaluated by analyzing of the dextromethorphan in presence of several substances with similar molecular structures and properties. Results from the HPLC analyses showed that the recoveries of dextromethorphan using MIP cartridges from human plasma samples in the range of 1-50 ng/mL were higher than 87%. Copyright © 2011 Elsevier B.V. All rights reserved.

Synthesis and characterization of core-shell magnetic molecularly imprinted polymers for solid-phase extraction and determination of Rhodamine B in food.

PubMed

Su, Xiaomeng; Li, Xiaoyan; Li, Junjie; Liu, Min; Lei, Fuhou; Tan, Xuecai; Li, Pengfei; Luo, Weiqiang

2015-03-15

Core-shell magnetic molecularly imprinted polymers (MIPs) nanoparticles (NPs), in which a Rhodamine B-imprinted layer was coated on Fe3O4 NPs. were synthesized. First, Fe3O4 NPs were prepared by a coprecipitation method. Then, amino-modified Fe3O4 NPs (Fe3O4@SiO2-NH2) was prepared. Finally, the MIPs were coated on the Fe3O4@SiO2-NH2 surface by the copolymerization with functional monomer, acrylamide, using a cross-linking agent, ethylene glycol dimethacrylate; an initiator, azobisisobutyronitrile and a template molecule, Rhodamine B. The Fe3O4@MIPs were characterized using a scanning electron microscope, Fourier transform infrared spectrometer, vibrating sample magnetometer, and re-binding experiments. The Fe3O4@MIPs showed a fast adsorption equilibrium, a highly improved imprinting capacity, and significant selectivity; they could be used as a solid-phase extraction material and detect illegal addition Rhodamine B in food. A method was developed for the selective isolation and enrichment of Rhodamine B in food samples with recoveries in the range 78.47-101.6% and the relative standard deviation was <2%. Copyright © 2014 Elsevier Ltd. All rights reserved.

Fabrication of a biomimetic adsorbent imprinted with a common specificity determinant for the removal of α- and β-amanitin from plasma.

PubMed

Tan, Lei; He, Rong; Li, Yongxian; Liang, Yong; Li, He; Tang, Youwen

2016-08-12

α-Amanitin and β-amanitin are the main toxins of mushroom poisoning. The application of traditional non-selective adsorbents is not satisfactory in clinical treatment of amanita mushroom poisoning due to lack of specificity adsorption capability of these adsorbents toward amanitin toxins. In the current work, we introduce a novel molecularly imprinted biomimetic adsorbent based on a ligand specificity determinant through surface imprinted strategy. Owing to the expensive price of the amanitin sources, we selected a typical common moiety of α, β-amanitin as specificity determinant to synthesize a template necessary for the preparation of molecularly imprinted polymers (MIPs). Computer simulation was used to initially select acidic methacrylic acid (MAA) and basic 4-vinyl pyridine (4-VP) together as functional monomers. The experiments further demonstrated that the synergistic interaction of MAA and 4-VP played a primary role in the recognition of α, β-amanitin by MIPs. By means of batch and packed-bed column experiment and the hemocompatibility evaluation, the resultant biomimetic adsorbent has been proved to be capable of selectively removing α, β-amanitin and possess good hemocompatibility. This novel adsorbent has great potential to find application in human plasma purification. Copyright © 2016 Elsevier B.V. All rights reserved.

Extended release of high molecular weight hydroxypropyl methylcellulose from molecularly imprinted, extended wear silicone hydrogel contact lenses.

PubMed

White, Charles J; McBride, Matthew K; Pate, Kayla M; Tieppo, Arianna; Byrne, Mark E

2011-08-01

Symptoms of contact lenses induced dry eye (CLIDE) are typically treated through application of macromolecular re-wetting agents via eye drops. Therapeutic soft contact lenses can be formulated to alleviate CLIDE symptoms by slowly releasing comfort agent from the lens. In this paper, we present an extended wear silicone hydrogel contact lens with extended, controllable release of 120 kDa hydroxypropyl methylcellulose (HPMC) using a molecular imprinting strategy. A commercial silicone hydrogel lens was tailored to release approximately 1000 μg of HPMC over a period of up to 60 days in a constant manner at a rate of 16 μg/day under physiological flowrates, releasing over the entire range of continuous wear. Release rates could be significantly varied by the imprinting effect and functional monomer to template ratio (M/T) with M/T values 0, 0.2, 2.8, 3.4 corresponding to HPMC release durations of 10, 13, 23, and 53 days, respectively. Lenses had high optical quality and adequate mechanical properties for contact lens use. This work highlights the potential of imprinting in the design and engineering of silicone hydrogel lenses to release macromolecules for the duration of wear, which may lead to decreased CLIDE symptoms and more comfortable contact lenses. Copyright © 2011 Elsevier Ltd. All rights reserved.

Synthesis of molecularly imprinted polymers by atom transfer radical polymerization for the solid-phase extraction of phthalate esters in edible oil.

PubMed

Chen, Ningning; He, Juan; Wu, Chaojun; Li, Yuanyuan; Suo, An; Wei, Hongliang; He, Lijun; Zhang, Shusheng

2017-03-01

Novel molecularly imprinted polymers of phthalate esters were prepared by atom transfer radical polymerization using methyl methacrylate as functional monomer, cyclohexanone as solvent, cuprous chloride as catalyst, 1-chlorine-1-ethyl benzene as initiator and 2,2-bipyridyl as cross-linker in the mixture of methanol and water (1:1, v/v). The effect of reaction conditions such as monomer ratio and template on the adsorption properties was investigated. The optimum condition was obtained by an orthogonal experiment. The obtained polymers were characterized using scanning electron microscopy. The binding property was studied with both static and dynamic methods. Results showed that the polymers exhibited excellent recognition capacity and outstanding selectivity for ten phthalate esters. Factors affecting the extraction efficiency of the molecularly imprinted solid-phase extraction were systematically investigated. An analytical method based on the molecularly imprinted coupled with gas chromatography and flame ionization detection was successfully developed for the simultaneous determination of ten phthalate esters from edible oil. The method detection limits were 0.10-0.25 μg/mL, and the recoveries of spiked samples were 82.5-101.4% with relative standard deviations of 1.24-5.37% (n = 6). © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Molecularly imprinted polymer cartridges coupled to high performance liquid chromatography (HPLC-UV) for simple and rapid analysis of fenthion in olive oil.

PubMed

Bakas, Idriss; Ben Oujji, Najwa; Istamboulié, Georges; Piletsky, Sergey; Piletska, Elena; Ait-Addi, Elhabib; Ait-Ichou, Ihya; Noguer, Thierry; Rouillon, Régis

2014-07-01

A combination of molecular modelling and a screening of the library of non-imprinted polymers (NIPs) was used to identify acrylamide as a functional monomer with high affinity towards fenthion, organophosphate insecticide, which is frequently used in the treatment of olives. A good correlation was found between the screening tests and modelling of monomer-template interactions performed using a computational approach. Acrylamide-based molecularly imprinted polymer (MIP) and non-imprinted polymer (NIP) were thermally synthesised in dimethyl formamide (porogen) using ethylene glycol dimethacrylate as a cross-linker and 1,1-azo-bis (isobutyronitrile) as an initiator. The chemical and physical properties of the prepared polymers were characterised. The binding of fenthion by the polymers was studied using solvents with different polarities. The developed MIP showed a high selectivity towards fenthion, compared to other organophosphates (dimethoate, methidathion malalthion), and allowed extraction of fenthion from olive oil samples with a recovery rate of about 96%. The extraction of fenthion using MIPs was much more effective than traditional C18 reverse-phase solid phase extraction and allowed to achieve a low detection limit (LOD) (5 µg L(-1)). Copyright © 2014 Elsevier B.V. All rights reserved.

Application of molecular imprinted polymer nanoparticles as a selective solid phase extraction for preconcentration and trace determination of 2,4-dichlorophenoxyacetic acid in the human urine and different water samples.

PubMed

Omidi, Fariborz; Behbahani, Mohammad; Sadeghi Abandansari, Hamid; Sedighi, Alireza; Shahtaheri, Seyed Jamaleddin

2014-01-01

A molecular-imprinted polymer nanoparticles (MIP-NP) for the selective preconcentration of 2,4-dichlorophenoxyacetic acid (2,4-D) is described. It was obtained by precipitation polymerization from methacrylic acid (the functional monomer), ethylene glycol dimethacrylate (the cross-linker), 2,2'-azobisisobutyronitrile (the initiator) and 2,4-D (the template molecule) in acetonitrile solution. The MIP-NPs were characterized by thermogravimetric analysis, and by scanning electron microscopy. Imprinted 2,4-D molecules were removed from the polymeric structure using acetic acid in methanol (15:85 v/v %) as the eluting solvent. The sorption and desorption process occur within 10 min and 15 min, respectively. The maximum sorbent capacity of the molecular imprinted polymer is 89.2 mg g(-1). The relative standard deviation and limit of detection for water samples by introduced selective solid phase extraction were 4.2% and 1.25 μg L(-1), and these data for urine samples were 4.7% and 1.80 μg L(-1), respectively. The method was applied to the determination of 2,4-D in the urine and different water samples.

Determination of Ten Macrolide Drugs in Environmental Water Using Molecularly Imprinted Solid-Phase Extraction Coupled with Liquid Chromatography-Tandem Mass Spectrometry.

PubMed

Song, Xuqin; Zhou, Tong; Li, Jiufeng; Zhang, Meiyu; Xie, Jingmeng; He, Limin

2018-05-14

With the extensive application of antibiotics in livestock, their contamination of the aquatic environment has received more attention. Molecularly imprinted polymer (MIP), as an eco-friendly and durable solid-phase extraction material, has shown great potential for the separation and enrichment of antibiotics in water. This study aims at developing a practical and economical method based on molecularly imprinted solid phase extraction (MISPE) combined with liquid chromatography-tandem mass spectrometry (LC-MS/MS) for simultaneously detecting ten macrolide drugs in different sources of water samples. The MIP was synthesized by bulk polymerization using tylosin as the template and methacrylic acid as the functional monomer. The MIP exhibited a favorable load-bearing capacity for water (>90 mL), which is more than triple that of non-molecularly imprinted polymers (NIP). The mean recoveries of macrolides at four spiked concentration levels (limit of quantification, 40, 100, and 400 ng/L) were 62.6⁻100.9%, with intra-day and inter-day relative standard deviations below 12.6%. The limit of detection and limit of quantification were 1.0⁻15.0 ng/L and 3.0⁻40.0 ng/L, respectively. Finally, the proposed method was successfully applied to the analysis of real water samples.

Enhanced molecular recognition for imprinted monolithic column containing polyhedral oligomeric silsesquioxanes by dendritic effect of mesoporous molecular sieve scaffolds.

PubMed

Yang, Fang-Fang; Li, Zai-Xuan; Xu, Yu-Jing; Huang, Yan-Ping; Liu, Zhao-Sheng

2018-06-07

The dendritic effect of nano mesoporous molecular sieve was first used to enhance molecular recognition of molecularly imprinted polymers (MIPs)-based polyhedral oligomeric silsesquioxanes (POSS). In this study, the MIPs were made using S-naproxen (S-NAP) as template molecule, 4-vinylpyridine (4-VP) as functional monomer, ethylene glycol dimethacrylate as cross-linker, 1-butyl-3-methylimidazoliumtetrafluoroborate ([BMIM]BF 4 )/DMSO as binary porogens, 1-propylmethacrylate-heptaisobutyl substituted as POSS monomer, and mesoporous molecular sieve (Mobil composition of matter No. 41, MCM-41) as dendritic scaffold. The influence of synthesis parameters on the imprinting effect, including the content of POSS monomer and derivatized MCM-41-MPS, the ratio of template to monomer, and the ratio of binary porogens were also investigated, respectively. The morphology of the polymers was characterized by scanning electron microscopy, nitrogen adsorption, and X-ray powder diffraction. The results showed that POSS&MCM-41-MPS MIP had a stronger imprinting effect with an imprinting factor 6.86, which is approximately 2.4, 2.3, and 3 times than that of POSS MIP, MCM-41-MPS MIP, and conventional MIP, respectively. The increase of affinity might be attributed to impediment of the chain motion of polymer due to improved POSS aggregation and the dipole interaction between the POSS units by introduce of MCM-41-MPS as scaffolds. The resulting POSS&MCM-41-MPS MIP was used as adsorbent for the enrichment of S-NAP in solid-phase extraction with a high recovery of 97.65% and the value of RSD was 0.94%.

Molecularly imprinted solid-phase extraction for the selective determination of bromhexine in human serum and urine with high performance liquid chromatography.

PubMed

Javanbakht, Mehran; Namjumanesh, Mohammad Hadi; Akbari-Adergani, Behrouz

2009-11-15

In this work, a novel method is described for the determination of bromhexine in biological fluids using molecularly imprinted solid-phase extraction as the sample cleanup technique combined with high performance liquid chromatography (HPLC). The water-compatible molecularly imprinted polymers (MIPs) were prepared using methacrylic acid as functional monomer, ethylene glycol dimethacrylate as cross-linker, chloroform as porogen and bromhexine as the template molecule. The novel imprinted polymer was used as a solid-phase extraction sorbent for the extraction of bromhexine from human serum and urine. Various parameters affecting the extraction efficiency of the polymer have been evaluated. The optimal conditions for molecularly imprinted solid-phase extraction (MISPE) consisted of conditioning 1 mL methanol and 1 mL of deionized water at neutral pH, loading of 5 mL of the water sample (25 microg L(-1)) at pH 6.0, washing using 2 mL acetonitrile/acetone (1/4, v/v) and elution with 3x 1 mL methanol/acetic acid (10/1, v/v). The MIP selectivity was evaluated by checking several substances with similar molecular structures to that of bromhexine. Results from the HPLC analyses showed that the calibration curve of bromhexine using MIP from human serum and urine is linear in the ranges of 0.5-100 and 1.5-100 microg L(-1) with good precisions (3.3% and 2.8% for 5.0 microg L(-1)), respectively. The recoveries for serum and urine samples were higher than 92%.

A pM leveled photoelectrochemical sensor for microcystin-LR based on surface molecularly imprinted TiO2@CNTs nanostructure.

PubMed

Liu, Meichuan; Ding, Xue; Yang, Qiwei; Wang, Yu; Zhao, Guohua; Yang, Nianjun

2017-06-05

A simple and highly sensitive photoelectrochemical (PEC) sensor towards Microcystin-LR (MC-LR), a kind of typical cyanobacterial toxin in water samples, was developed on a surface molecular imprinted TiO 2 coated multiwalled carbon nanotubes (MI-TiO 2 @CNTs) hybrid nanostructure. It was synthesized using a feasible two-step sol-gel method combining with in situ surface molecular imprinting technique (MIT). With a controllable core-shell tube casing structure, the resultant MI-TiO 2 @CNTs are enhanced greatly in visible-light driven response capacity. In comparison with the traditional TiO 2 (P25) and non-imprinted (NI-)TiO 2 @CNTs, the MI-TiO 2 @CNTs based PEC sensor showed a much higher photoelectric oxidation capacity towards MC-LR. Using this sensor, the determination of MC-LR was doable in a wide linear range from 1.0pM to 3.0nM with a high photocurrent response sensitivity. An outstanding selectivity towards MC-LR was further achieved with this sensor, proven by simultaneously monitoring 100-fold potential co-existing interferences. The superiority of the obtained MC-LR sensor in sensitivity and selectivity is mainly attributed to the high specific surface area and excellent photoelectric activity of TiO 2 @CNTs heterojunction structure, as well as the abundant active recognition sites on its functionalized molecular imprinting surface. A promising PEC analysis platform with high sensitivity and selectivity for MC-LR has thus been provided. Copyright © 2017 Elsevier B.V. All rights reserved.

Molecular imprinting-based separation methods for selective analysis of fluoroquinolones in soils.

PubMed

Turiel, Esther; Martín-Esteban, Antonio; Tadeo, José Luis

2007-11-23

Molecularly imprinted polymers (MIPs) for fluoroquinolone antibiotics (FQs) have been synthesised in one single preparative step by precipitation polymerisation using ciprofloxacin (CIP) as template. Combinations of methacrylic acid (MAA) or 4-vinylpyridine (VP) as functional monomers, ethylene glycol dimethacrylate as crosslinker and dichloromethane, methanol, acetonitrile or toluene as porogens were tested. The experiments carried out by molecularly imprinted solid-phase extraction (MISPE) in cartridges did not allow to detect any imprint effect in the VP-based polymers whereas it was clearly observed in the MAA-based polymers. Among them, the MIP prepared in methanol using MAA as monomer showed the best performance and was chosen for further experiments. The ability of the selected MIP for the selective recognition of other widely used FQs (enoxacin, norfloxacin, danofloxacin and enrofloxacin) and quinolones (Qs) (cinoxacin, flumequine, nalidixic acid and oxolinic acid) was evaluated. The obtained results revealed the high selectivity of the obtained polymer, which was able to distinguish between FQs, that were recognised and retained onto the MIP cartridge, and Qs, which were washed out during loading and washing steps. The MIP was then packed into a stainless steel column (50mmx4.6mm i.d.) and evaluated as chromatography column for screening of FQs in soil samples. The mobile phase composition, flow rate, and the elution profile were then optimised in order to improve peak shape without sacrifying imprinting factor. Finally, under optimised conditions, soil samples spiked with CIP or with a mixture of fluoroquinolones in concentration of 0.5microgg(-1) were successfully analysed by the developed MIP-based procedures.

Rational design of molecularly imprinted polymer: the choice of cross-linker.

PubMed

Muhammad, Turghun; Nur, Zohre; Piletska, Elena V; Yimit, Osmanjan; Piletsky, Sergey A

2012-06-07

The paper describes a rational approach for the selection of cross-linkers during the development of molecularly imprinted polymers (MIPs). As a model system for this research MIPs specific for the drug zidovudine (AZT) were designed and tested. Three cross-linkers trimethylolpropane trimethacrylate (TRIM), ethylene glycol dimethacrylate (EGDMA) and divinylbenzene (DVB) were studied. The analogue of zidovudine (AZT) ester (AZT-ES) was used as a dummy template. The imprinting factors for all of the polymers in the static adsorption experiments were calculated. The data on the AZT adsorption by control polymers (CP), which were prepared with different cross-linkers without a functional monomer, was also analyzed. DVB was found to be more inert towards zidovudine than EGDMA and TRIM, which was confirmed by both molecular modelling and adsorption experiments. It was demonstrated that DVB-based polymers had a higher imprinting factor (I = 1.85) compared with other tested cross-linked polymers. It was suggested that the selection of the cross-linker should be based on the strength of the interaction with the template: the cross-linker which displays lower binding of the template should be preferential because it generates MIPs with lower non-specific binding and a higher imprinting factor, and therefore specificity. Which cross-linker to use for the preparation of any particular MIP can be determined by analysis of the interactions between the cross-linker and template. This could be done either virtually using computational modelling or by template adsorption using a small library of polymers prepared using different cross-linkers.

MeCP2 deficiency in Rett syndrome causes epigenetic aberrations at the PWS/AS imprinting center that affects UBE3A expression.

PubMed

Makedonski, Kirill; Abuhatzira, Liron; Kaufman, Yotam; Razin, Aharon; Shemer, Ruth

2005-04-15

Rett syndrome (RS) is a severe and progressive neurodevelopmental disorder caused by heterozygous mutations in the X-linked methyl CpG binding protein 2 (MeCP2) gene. MeCP2 is a nuclear protein that binds specifically to methylated DNA and functions as a general transcription repressor in the context of chromatin remodeling complexes. RS shares clinical features with those of Angelman syndrome (AS), an imprinting neurodevelopmental disorder. In AS patients, the maternally expressed copy of UBE3A that codes for the ubiquitin protein ligase 3A (E6-AP) is repressed. The similar phenotype of these two syndromes led us to hypothesize that part of the RS phenotype is due to MeCP2-associated silencing of UBE3A. Indeed, UBE3A mRNA and protein are shown here to be significantly reduced in human and mouse MECP2 deficient brains. This reduced UBE3A level was associated with biallelic production of the UBE3A antisense RNA. In addition, MeCP2 deficiency resulted in elevated histone H3 acetylation and H3(K4) methylation and reduced H3(K9) methylation at the PWS/AS imprinting center, with no effect on DNA methylation or SNRPN expression. We conclude, therefore, that MeCP2 deficiency causes epigenetic aberrations at the PWS imprinting center. These changes in histone modifications result in loss of imprinting of the UBE3A antisense gene in the brain, increase in UBE3A antisense RNA level and, consequently reduction in UBE3A production.

Short interspersed transposable elements (SINEs) are excluded from imprinted regions in the human genome.

PubMed

Greally, John M

2002-01-08

To test whether regions undergoing genomic imprinting have unique genomic characteristics, imprinted and nonimprinted human loci were compared for nucleotide and retroelement composition. Maternally and paternally expressed subgroups of imprinted genes were found to differ in terms of guanine and cytosine, CpG, and retroelement content, indicating a segregation into distinct genomic compartments. Imprinted regions have been normally permissive to L1 long interspersed transposable element retroposition during mammalian evolution but universally and significantly lack short interspersed transposable elements (SINEs). The primate-specific Alu SINEs, as well as the more ancient mammalian-wide interspersed repeat SINEs, are found at significantly low densities in imprinted regions. The latter paleogenomic signature indicates that the sequence characteristics of currently imprinted regions existed before the mammalian radiation. Transitions from imprinted to nonimprinted genomic regions in cis are characterized by a sharp inflection in SINE content, demonstrating that this genomic characteristic can help predict the presence and extent of regions undergoing imprinting. During primate evolution, SINE accumulation in imprinted regions occurred at a decreased rate compared with control loci. The constraint on SINE accumulation in imprinted regions may be mediated by an active selection process. This selection could be because of SINEs attracting and spreading methylation, as has been found at other loci. Methylation-induced silencing could lead to deleterious consequences at imprinted loci, where inactivation of one allele is already established, and expression is often essential for embryonic growth and survival.

Short interspersed transposable elements (SINEs) are excluded from imprinted regions in the human genome

PubMed Central

Greally, John M.

2002-01-01

To test whether regions undergoing genomic imprinting have unique genomic characteristics, imprinted and nonimprinted human loci were compared for nucleotide and retroelement composition. Maternally and paternally expressed subgroups of imprinted genes were found to differ in terms of guanine and cytosine, CpG, and retroelement content, indicating a segregation into distinct genomic compartments. Imprinted regions have been normally permissive to L1 long interspersed transposable element retroposition during mammalian evolution but universally and significantly lack short interspersed transposable elements (SINEs). The primate-specific Alu SINEs, as well as the more ancient mammalian-wide interspersed repeat SINEs, are found at significantly low densities in imprinted regions. The latter paleogenomic signature indicates that the sequence characteristics of currently imprinted regions existed before the mammalian radiation. Transitions from imprinted to nonimprinted genomic regions in cis are characterized by a sharp inflection in SINE content, demonstrating that this genomic characteristic can help predict the presence and extent of regions undergoing imprinting. During primate evolution, SINE accumulation in imprinted regions occurred at a decreased rate compared with control loci. The constraint on SINE accumulation in imprinted regions may be mediated by an active selection process. This selection could be because of SINEs attracting and spreading methylation, as has been found at other loci. Methylation-induced silencing could lead to deleterious consequences at imprinted loci, where inactivation of one allele is already established, and expression is often essential for embryonic growth and survival. PMID:11756672

EXTRA-EMBRYONIC-SPECIFIC IMPRINTED EXPRESSION IS RESTRICTED TO DEFINED LINEAGES IN THE POST-IMPLANTATION EMBRYO

PubMed Central

Hudson, Quanah J.; Seidl, Christine I.M.; Kulinski, Tomasz M.; Huang, Ru; Warczok, Katarzyna E.; Bittner, Romana; Bartolomei, Marisa S.; Barlow, Denise P.

2011-01-01

A subset of imprinted genes in the mouse have been reported to show imprinted expression that is restricted to the placenta, a short-lived extra-embryonic organ. Notably these so-called 'placental-specific' imprinted genes are expressed from both parental alleles in embryo and adult tissues. The placenta is an embryonic-derived organ that is closely associated with maternal tissue and as a consequence, maternal contamination can be mistaken for maternal-specific imprinted expression. The complexity of the placenta, which arises from multiple embryonic lineages, poses additional problems in accurately assessing allele-specific repressive epigenetic modifications in genes that also show lineage-specific silencing in this organ. These problems require that extra evidence be obtained to support the imprinted status of genes whose imprinted expression is restricted to the placenta. We show here that the extra-embryonic visceral yolk sac (VYS), a nutritive membrane surrounding the developing embryo, shows a similar 'extra-embryonic-lineage-specific' pattern of imprinted expression. We present an improved enzymatic technique for separating the bilaminar VYS and show that this pattern of imprinted expression is restricted to the endoderm layer. Finally, we show that VYS 'extra-embryonic-lineage-specific' imprinted expression is regulated by DNA methylation in a similar manner as shown for genes showing multi-lineage imprinted expression in extra-embryonic, embryonic and adult tissues. These results show that the VYS is an improved model for studying the epigenetic mechanisms regulating extra-embryonic-lineage-specific imprinted expression. PMID:21354127

Analysis of the platypus genome suggests a transposon origin for mammalian imprinting.

PubMed

Pask, Andrew J; Papenfuss, Anthony T; Ager, Eleanor I; McColl, Kaighin A; Speed, Terence P; Renfree, Marilyn B

2009-01-01

Genomic imprinting is an epigenetic phenomenon that results in monoallelic gene expression. Many hypotheses have been advanced to explain why genomic imprinting evolved in mammals, but few have examined how it arose. The host defence hypothesis suggests that imprinting evolved from existing mechanisms within the cell that act to silence foreign DNA elements that insert into the genome. However, the changes to the mammalian genome that accompanied the evolution of imprinting have been hard to define due to the absence of large scale genomic resources between all extant classes. The recent release of the platypus genome has provided the first opportunity to perform comparisons between prototherian (monotreme; which appear to lack imprinting) and therian (marsupial and eutherian; which have imprinting) mammals. We compared the distribution of repeat elements known to attract epigenetic silencing across the entire genome from monotremes and therian mammals, particularly focusing on the orthologous imprinted regions. There is a significant accumulation of certain repeat elements within imprinted regions of therian mammals compared to the platypus. Our analyses show that the platypus has significantly fewer repeats of certain classes in the regions of the genome that have become imprinted in therian mammals. The accumulation of repeats, especially long terminal repeats and DNA elements, in therian imprinted genes and gene clusters is coincident with, and may have been a potential driving force in, the development of mammalian genomic imprinting. These data provide strong support for the host defence hypothesis.

Analysis of the platypus genome suggests a transposon origin for mammalian imprinting

PubMed Central

Pask, Andrew J; Papenfuss, Anthony T; Ager, Eleanor I; McColl, Kaighin A; Speed, Terence P; Renfree, Marilyn B

2009-01-01

Background Genomic imprinting is an epigenetic phenomenon that results in monoallelic gene expression. Many hypotheses have been advanced to explain why genomic imprinting evolved in mammals, but few have examined how it arose. The host defence hypothesis suggests that imprinting evolved from existing mechanisms within the cell that act to silence foreign DNA elements that insert into the genome. However, the changes to the mammalian genome that accompanied the evolution of imprinting have been hard to define due to the absence of large scale genomic resources between all extant classes. The recent release of the platypus genome has provided the first opportunity to perform comparisons between prototherian (monotreme; which appear to lack imprinting) and therian (marsupial and eutherian; which have imprinting) mammals. Results We compared the distribution of repeat elements known to attract epigenetic silencing across the entire genome from monotremes and therian mammals, particularly focusing on the orthologous imprinted regions. There is a significant accumulation of certain repeat elements within imprinted regions of therian mammals compared to the platypus. Conclusions Our analyses show that the platypus has significantly fewer repeats of certain classes in the regions of the genome that have become imprinted in therian mammals. The accumulation of repeats, especially long terminal repeats and DNA elements, in therian imprinted genes and gene clusters is coincident with, and may have been a potential driving force in, the development of mammalian genomic imprinting. These data provide strong support for the host defence hypothesis. PMID:19121219

Electrochemical sensor based on molecularly imprinted polymer film via sol-gel technology and multi-walled carbon nanotubes-chitosan functional layer for sensitive determination of quinoxaline-2-carboxylic acid.

PubMed

Yang, Yukun; Fang, Guozhen; Liu, Guiyang; Pan, Mingfei; Wang, Xiaomin; Kong, Lingjie; He, Xinlei; Wang, Shuo

2013-09-15

Quinoxaline-2-carboxylic acid (QCA) is difficult to measure since only trace levels are present in commercial meat products. In this study, a rapid, sensitive and selective molecularly imprinted electrochemical sensor for QCA determination was successfully constructed by combination of a novel modified glassy carbon electrode (GCE) and differential pulse voltammetry (DPV). The GCE was fabricated via stepwise modification of multi-walled carbon nanotubes (MWNTs)-chitosan (CS) functional composite and a sol-gel molecularly imprinted polymer (MIP) film on the surface. MWNTs-CS composite was used to enhance the electron transfer rate and expand electrode surface area, and consequently amplify QCA reduction electrochemical response. The imprinted mechanism and experimental parameters affecting the performance of MIP film were discussed in detail. The resulting MIP/sol-gel/MWNTs-CS/GCE was characterized using various electrochemical methods involving cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and DPV. The sensor using MIP/sol-gel/MWNTs-CS/GCE as working electrode showed a linear current response to the target QCA concentration in the wide range from 2.0×10(-6) to 1.0×10(-3)molL(-1) with a low detection limit of 4.4×10(-7)molL(-1) (S/N=3). The established sensor with excellent reproductivity and stability was applied to evaluate commercial pork products. At five concentration levels, the recoveries and standard deviations were calculated as 93.5-98.6% and 1.7-3.3%, respectively, suggesting the proposed sensor is promising for the accurate quantification of QCA at trace levels in meat samples. Copyright © 2013 Elsevier B.V. All rights reserved.

A highly selective electrochemical sensor based on molecularly imprinted polypyrrole-modified gold electrode for the determination of glyphosate in cucumber and tap water.

PubMed

Zhang, Chao; She, Yongxin; Li, Tengfei; Zhao, Fengnian; Jin, Maojun; Guo, Yirong; Zheng, Lufei; Wang, Shanshan; Jin, Fen; Shao, Hua; Liu, Haijin; Wang, Jing

2017-12-01

An electrochemical sensor based on molecularly imprinted polypyrrole (MIPPy) was developed for selective and sensitive detection of the herbicide glyphosate (Gly) in cucumber and tap water samples. The sensor was prepared via synthesis of molecularly imprinted polymers on a gold electrode in the presence of Gly as the template molecule and pyrrole as the functional monomer by cyclic voltammetry (CV). The sensor preparation conditions including the ratio of template to functional monomers, number of CV cycles in the electropolymerization process, the method of template removal, incubation time, and pH were optimized. Under the optimal experimental conditions, the DPV peak currents of hexacyanoferrate/hexacyanoferrite changed linearly with Gly concentration in the range from 5 to 800 ng mL -1 , with a detection limit of 0.27 ng mL -1 (S/N = 3). The sensor was used to detect the concentration of Gly in cucumber and tap water samples, with recoveries ranging from 72.70 to 98.96%. The proposed sensor showed excellent selectivity, good stability and reversibility, and could detect the Gly in real samples rapidly and sensitively. Graphical abstract Schematic illustration of the experimental procedure to detect Gly using the MIPPy electrode.

Evidence of Olfactory Imprinting at an Early Life Stage in Pink Salmon (Oncorhynchus gorbuscha)

PubMed Central

Bett, Nolan N.; Hinch, Scott G.; Dittman, Andrew H.; Yun, Sang-Seon

2016-01-01

Pacific salmon (Oncorhynchus spp.) navigate towards spawning grounds using olfactory cues they imprinted on as juveniles. The timing at which imprinting occurs has been studied extensively, and there is strong evidence that salmon imprint on their natal water during the parr-smolt transformation (PST). Researchers have noted, however, that the life histories of some species of Pacific salmon could necessitate imprinting prior to the PST. Juvenile pink salmon (O. gorbuscha) spend less time in fresh water than any other species of Pacific salmon, and presumably must imprint on their natal water at a very young age. The time at which imprinting occurs in this species, however, has not been experimentally tested. We exposed juvenile pink salmon as alevins to phenethyl alcohol (PEA) or control water, reared these fish to adulthood, and then tested their behavioural responses to PEA to determine whether the fish successfully imprinted. We found that pink salmon exposed to PEA as alevins were attracted to the chemical as adults, suggesting that imprinting can occur during this stage. Our finding provides some of the first evidence to support the long-standing belief that imprinting can occur in pink salmon prior to the PST. PMID:27827382

Evidence of Olfactory Imprinting at an Early Life Stage in Pink Salmon (Oncorhynchus gorbuscha).

PubMed

Bett, Nolan N; Hinch, Scott G; Dittman, Andrew H; Yun, Sang-Seon

2016-11-09

Pacific salmon (Oncorhynchus spp.) navigate towards spawning grounds using olfactory cues they imprinted on as juveniles. The timing at which imprinting occurs has been studied extensively, and there is strong evidence that salmon imprint on their natal water during the parr-smolt transformation (PST). Researchers have noted, however, that the life histories of some species of Pacific salmon could necessitate imprinting prior to the PST. Juvenile pink salmon (O. gorbuscha) spend less time in fresh water than any other species of Pacific salmon, and presumably must imprint on their natal water at a very young age. The time at which imprinting occurs in this species, however, has not been experimentally tested. We exposed juvenile pink salmon as alevins to phenethyl alcohol (PEA) or control water, reared these fish to adulthood, and then tested their behavioural responses to PEA to determine whether the fish successfully imprinted. We found that pink salmon exposed to PEA as alevins were attracted to the chemical as adults, suggesting that imprinting can occur during this stage. Our finding provides some of the first evidence to support the long-standing belief that imprinting can occur in pink salmon prior to the PST.

Genome-wide histone state profiling of fibroblasts from the opossum, Monodelphis domestica, identifies the first marsupial-specific imprinted gene

PubMed Central

2014-01-01

Background Imprinted genes have been extensively documented in eutherian mammals and found to exhibit significant interspecific variation in the suites of genes that are imprinted and in their regulation between tissues and developmental stages. Much less is known about imprinted loci in metatherian (marsupial) mammals, wherein studies have been limited to a small number of genes previously known to be imprinted in eutherians. We describe the first ab initio search for imprinted marsupial genes, in fibroblasts from the opossum, Monodelphis domestica, based on a genome-wide ChIP-seq strategy to identify promoters that are simultaneously marked by mutually exclusive, transcriptionally opposing histone modifications. Results We identified a novel imprinted gene (Meis1) and two additional monoallelically expressed genes, one of which (Cstb) showed allele-specific, but non-imprinted expression. Imprinted vs. allele-specific expression could not be resolved for the third monoallelically expressed gene (Rpl17). Transcriptionally opposing histone modifications H3K4me3, H3K9Ac, and H3K9me3 were found at the promoters of all three genes, but differential DNA methylation was not detected at CpG islands at any of these promoters. Conclusions In generating the first genome-wide histone modification profiles for a marsupial, we identified the first gene that is imprinted in a marsupial but not in eutherian mammals. This outcome demonstrates the practicality of an ab initio discovery strategy and implicates histone modification, but not differential DNA methylation, as a conserved mechanism for marking imprinted genes in all therian mammals. Our findings suggest that marsupials use multiple epigenetic mechanisms for imprinting and support the concept that lineage-specific selective forces can produce sets of imprinted genes that differ between metatherian and eutherian lines. PMID:24484454

Early imprinting in wild and game-farm mallards (Anas platyrhynchos): genotype and arousal

USGS Publications Warehouse

Cheng, K.M.; Shoffner, R.N.; Phillips, R.E.; Shapiro, L.J.

1979-01-01

Early imprinting was studied under laboratory conditions in five lines of mallards (Anas platyrhynchos) with different degrees of wildness obtained through pedigreed breeding. Data were analyzed by the least squares method. Wild ducklings imprinted better than game-farm (domesticated) ducklings, and heterosis was demonstrated to exist in imprinting traits. Nonadditive genetic variations and genotype-environmental interactions are discussed as possible causes for the heterosis observed. Differences in imprinting between genetic lines are attributed, at least partly, to differences in arousal level during the ducklings' first exposure to the imprinting stimulus.

Molecularly Imprinted Polymers for Ochratoxin A Extraction and Analysis

PubMed Central

Yu, Jorn C. C.; Lai, Edward P. C.

2010-01-01

Molecularly imprinted polymers (MIPs) are considered as polymeric materials that mimic the functionality of antibodies. MIPs have been utilized for a wide variety of applications in chromatography, solid phase extraction, immunoassays, and sensor recognition. In this article, recent advances of MIPs for the extraction and analysis of ochratoxins are discussed. Selection of functional monomers to bind ochratoxin A (OTA) with high affinities, optimization of extraction procedures, and limitations of MIPs are compared from different reports. The most relevant examples in the literature are described to clearly show how useful these materials are. Strategies on MIP preparation and schemes of analytical methods are also reviewed in order to suggest the next step that would make better use of MIPs in the field of ochratoxin research. The review ends by outlining the remaining issues and impediments. PMID:22069649

A nanocomposite optosensor containing carboxylic functionalized multiwall carbon nanotubes and quantum dots incorporated into a molecularly imprinted polymer for highly selective and sensitive detection of ciprofloxacin.

PubMed

Yuphintharakun, Naphat; Nurerk, Piyaluk; Chullasat, Kochaporn; Kanatharana, Proespichaya; Davis, Frank; Sooksawat, Dhassida; Bunkoed, Opas

2018-08-05

A nanocomposite optosensor consisting of carboxylic acid functionalized multiwall carbon nanotubes and CdTe quantum dots embedded inside a molecularly imprinted polymer (COOH@MWCNT-MIP-QDs) was developed for trace ciprofloxacin detection. The COOH@MWCNT-MIP-QDs were synthesized through a facile sol-gel process using ciprofloxacin as a template molecule, 3-aminopropylethoxysilane as a functional monomer and tetraethoxysilane as a cross-linker at a molar ratio of 1:8:20. The synthesized nanocomposite optosensor had high sensitivity, excellent specificity and high binding affinity to ciprofloxacin. Under optimal conditions, the fluorescence intensity of the optosensor decreased in a linear fashion with the concentration of ciprofloxacin and two linear dynamic ranges were obtained, 0.10-1.0 μg L -1 and 1.0-100.0 μg L -1 with a very low limit of detection of 0.066 μg L -1 . The imprinting factors of the two linear range were 17.67 and 4.28, respectively. The developed nanocomposite fluorescence probe was applied towards the determination of ciprofloxacin levels in chicken muscle and milk samples with satisfactory recoveries being obtained in the range of 82.6 to 98.4%. The results were also in good agreement with a HPLC method which indicates that the optosensor can be used as a sensitive, selective and rapid method to detect ciprofloxacin in chicken and milk samples. Copyright © 2018 Elsevier B.V. All rights reserved.

Imprints of magnetic power and helicity spectra on radio polarimetry statistics

NASA Astrophysics Data System (ADS)

Junklewitz, H.; Enßlin, T. A.

2011-06-01

The statistical properties of turbulent magnetic fields in radio-synchrotron sources should be imprinted on the statistics of polarimetric observables. In search of these imprints, i.e. characteristic modifications of the polarimetry statistics caused by magnetic field properties, we calculate correlation and cross-correlation functions from a set of observables that contain total intensity I, polarized intensity P, and Faraday depth φ. The correlation functions are evaluated for all combinations of observables up to fourth order in magnetic field B. We derive these analytically as far as possible and from first principles using only some basic assumptions, such as Gaussian statistics for the underlying magnetic field in the observed region and statistical homogeneity. We further assume some simplifications to reduce the complexity of the calculations, because for a start we were interested in a proof of concept. Using this statistical approach, we show that it is possible to gain information about the helical part of the magnetic power spectrum via the correlation functions < P(kperp) φ(k'_{perp)φ(k''perp)>B} and < I(kperp) φ(k'_{perp)φ(k''perp)>B}. Using this insight, we construct an easy-to-use test for helicity called LITMUS (Local Inference Test for Magnetic fields which Uncovers heliceS), which gives a spectrally integrated measure of helicity. For now, all calculations are given in a Faraday-free case, but set up so that Faraday rotational effects can be included later.

Expanding Cancer Detection Using Molecular Imprinting for a Novel Point-of-Care Diagnostic Device

NASA Astrophysics Data System (ADS)

Yu, Yingjie; Rafailovich, Miriam; Wang, Yantian; Kang, Yeona; Zhang, Lingxi; Rigas, Basil; Division of Gastroenterology, School of Medicine Team

2013-03-01

We propose the use of a potentiometric biosensor that incorporates the efficient and specific molecular imprinting (MI) method with a self-assembled monolayer (SAM). We first tested the biosensor using carcinoembryonic antigen, CEA, a biomarker associated with pancreatic cancer. No change in detection efficiency was observed, indicating that the sensor is able to discriminate for the template analyte even in concentrated solution of similar substances. In addition, we use biosensor to discriminate normal fibrinogen and damaged fibrinogen, which is critical for the detection of bleeding disorder. Computer simulations of the protein structure were performed in order to estimate the changes in morphology and determine the sensitivity of the biosensor to conformational changes in the proteins. We found that even small changes in PH can generate rotation of the surface functional groups. Yet, the results show that only when the detection and imprinting conditions are similar, robust signals occurs. Hence we concluded that both morphology and surface chemistry play a role in the recognition.

Expanding Cancer Detection Using Molecular Imprinting for a Novel Point-of-Care Diagnostic Device

NASA Astrophysics Data System (ADS)

Yu, Yingjie; Rafailovich, Miriam; Wang, Yantian; Ranjbaran, Alina; Wang, Tom; Nam, David

2012-02-01

We propose the use of a potentiometric biosensor that incorporates the efficient and specific molecular imprinting (MI) method with a self-assembled monolayer (SAM). We first tested the biosensor using carcinoembryonic antigen, CEA, a biomarker associated with pancreatic cancer. No change in detection efficiency was observed when detection was performed in the presence of 100% serum albumin, indicating that the sensor is able to discriminate for the template analyte even in concentrated solution of similar substances. Computer simulations of the protein structure were performed in order to estimate the changes in morphology and determine the sensitivity of the biosensor to conformational changes in the proteins. We found that even small changes in PH can generate rotation of the surface functional groups, without significant change in the morphology. Yet, the results show that only when the detection and imprinting conditions are similar, robust signals occurs. Hence we concluded that both morphology and surface chemistry play a role in the recognition.

Synthesis and application of ion imprinting polymer coated magnetic multi-walled carbon nanotubes for selective adsorption of nickel ion

NASA Astrophysics Data System (ADS)

He, Junnan; Shang, Hongzhou; Zhang, Xing; Sun, Xiaoran

2018-01-01

A novel nickel ion imprinted polymers (IIPs) based on multi-walled carbon nanotubes (MWCNTs) were synthesized inverse emulsion system, using chitosan(CS) and acrylic acid as the functional monomers, Ni (II) as the template, and N' N-methylene bis-acrylamide as the cross-linker. The chemical structure and morphological feature of the IIPs were characterized by scanning electron microscopy (SEM), Thermogravimetry (TG), X-ray diffraction (XRD), and Fourier transform infrared spectrometer (FTIR). The studies indicated that the gel layer was well grafted on the surface of MWCNTs. Studies on the adsorption ability of the IIPs, by atomic absorption spectrophotometry, demonstrated that IIPs possessed excellent adsorption and selective ability towards Ni (II), fitting to pseudo second-order kinetic isotherms and with a maximum capacity of 19.86 mg/g, and selectivity factor of 13.09 and 4.42. The electrochemical performance of ion imprinting carbon paste electrode (CPE/IIPs) was characterized by Cyclic voltammetry (CV). Studies have shown that CPE/IIPs showed excellent electrochemical performance.

Imprinted and X-linked non-coding RNAs as potential regulators of human placental function

PubMed Central

Buckberry, Sam; Bianco-Miotto, Tina; Roberts, Claire T

2014-01-01

Pregnancy outcome is inextricably linked to placental development, which is strictly controlled temporally and spatially through mechanisms that are only partially understood. However, increasing evidence suggests non-coding RNAs (ncRNAs) direct and regulate a considerable number of biological processes and therefore may constitute a previously hidden layer of regulatory information in the placenta. Many ncRNAs, including both microRNAs and long non-coding transcripts, show almost exclusive or predominant expression in the placenta compared with other somatic tissues and display altered expression patterns in placentas from complicated pregnancies. In this review, we explore the results of recent genome-scale and single gene expression studies using human placental tissue, but include studies in the mouse where human data are lacking. Our review focuses on the ncRNAs epigenetically regulated through genomic imprinting or X-chromosome inactivation and includes recent evidence surrounding the H19 lincRNA, the imprinted C19MC cluster microRNAs, and X-linked miRNAs associated with pregnancy complications. PMID:24081302

A study of a new TSM bio-mimetic sensor using a molecularly imprinted polymer coating and its application for the determination of nicotine in human serum and urine.

PubMed

Tan, Y; Yin, J; Liang, C; Peng, H; Nie, L; Yao, S

2001-03-01

A new bio-mimetic quartz crystal thickness-shear-mode (TSM) sensor, using an imprinted polymer coating as the sensitive material, has been fabricated and applied to the determination of nicotine (NIC) in human serum and urine. The molecularly imprinted polymer (MIP) was synthesized using NIC as the template molecule and methacrylic acid (MAA) as the functional monomer. The sensor showed high selectivity and a sensitive response to NIC in aqueous system. The linear response range of the sensor was between 5.0 x 10(-8) and 1.0 x 10(-4) M with a detection limit of 2.5 x 10(-8) M. The viscoelasticity of the coating in the air and in liquid has been studied by the impedance spectrum. The MIP sensor was stable and exhibited effective reproducibility. Satisfactory results were achieved in the detection of the real samples.

Water-compatible molecularly imprinted polymers for efficient direct injection on-line solid-phase extraction of ropivacaine and bupivacaine from human plasma.

PubMed

Cobb, Zoe; Sellergren, Börje; Andersson, Lars I

2007-12-01

Two novel molecularly imprinted polymers (MIPs) selected from a combinatorial library of bupivacaine imprinted polymers were used for selective on-line solid-phase extraction of bupivacaine and ropivacaine from human plasma. The MIPs were prepared using methacrylic acid as the functional monomer, ethylene glycol dimethacrylate as the cross-linking monomer and in addition hydroxyethylmethacrylate to render the polymer surface hydrophilic. The novel MIPs showed high selectivity for the analytes and required fewer and lower concentrations of additives to suppress non-specific adsorption compared with a conventional MIP. This enabled the development of an on-line system for direct extraction of buffered plasma. Selective extraction was achieved without the use of time-consuming solvent switch steps, and transfer of the analytes from the MIP column to the analytical column was carried out under aqueous conditions fully compatible with reversed-phase LC gradient separation of analyte and internal standard. The MIPs showed excellent aqueous compatibility and yielded extractions with acceptable recovery and high selectivity.

Sensitive determination of citrinin based on molecular imprinted electrochemical sensor

NASA Astrophysics Data System (ADS)

Atar, Necip; Yola, Mehmet Lütfi; Eren, Tanju

2016-01-01

In this report, a novel molecular imprinted voltammetric sensor based on glassy carbon electrode (GCE) modified with platinum nanoparticles (PtNPs) involved in a polyoxometalate (H3PW12O40, POM) functionalized reduced graphene oxide (rGO) was prepared for the determination of citrinin (CIT). The developed surfaces were characterized by using scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD) method. CIT imprinted GCE was prepared via electropolymerization process of 80.0 mM pyrrole as monomer in the presence of phosphate buffer solution (pH 6.0) containing 20.0 mM CIT. The linearity range and the detection limit of the developed method were calculated as 1.0 × 10-12-1.0 × 10-10 M and 2.0 × 10-13 M, respectively. In addition, the voltammetric sensor was applied to rye samples. The stability and selectivity of the voltammetric sensor were also reported.

Determination of L-phenylalanine on-line based on molecularly imprinted polymeric microspheres and flow injection chemiluminescence

NASA Astrophysics Data System (ADS)

Qiu, Huamin; Xi, Yulei; Lu, Fuguang; Fan, Lulu; Luo, Chuannan

2012-02-01

A novel molecular imprinting-chemiluminescence (MIP-CL) sensor for the determination of L-phenylalanine (Phe) using molecularly imprinted polymer (MIP) as recognition element is reported. The Phe-MIP was synthesized using acrylamide (AM) as functional monomer and ethylene glycol dimethacrylate (EGDMA) as cross-linker, 2,2-azobisisobutyronitrile (AIBN) as initiator and the polymers' properties were characterized. Then the synthesized MIP was employed as recognition element by packing into flow cell to establish a novel flow injection CL sensor. The CL intensity responded linearly to the concentration of Phe in the range 1.3 × 10 -6 to 5.44 × 10 -4 mol/L with a detection limit of 6.23 × 10 -7 mol/L (3 σ), which is lower than that of conventional methods. The sensor is reusable and has a great improvement in sensitivity and selectivity for CL analysis. As a result, the new MIP-CL sensor had been successfully applied to the determination of Phe in samples.

Surface-modified multifunctional MIP nanoparticles

PubMed Central

Moczko, Ewa; Poma, Alessandro; Guerreiro, Antonio; de Vargas Sansalvador, Isabel Perez; Caygill, Sarah; Canfarotta, Francesco; Whitcombe, Michael J.; Piletsky, Sergey

2015-01-01

The synthesis of core-shell molecularly imprinted polymer nanoparticles (MIP NPs) has been performed using a novel solid-phase approach on immobilised templates. The same solid phase also acts as protective functionality for high affinity binding sites during subsequent derivatisation/shell formation. This procedure allows for the rapid synthesis, controlled separation and purification of high-affinity materials, with each production cycle taking just 2 hours. The aim of this approach is to synthesise uniformly-sized imprinted materials at the nanoscale which can be readily grafted with various polymers without affecting their affinity and specificity. For demonstration purposes we grafted anti-melamine MIP NPs with coatings which introduce the following surface characteristics: high polarity (PEG methacrylate); electro-activity (vinyl ferrocene); fluorescence (eosin acrylate); thiol groups (pentaerythritol tetrakis(3-mercaptopropionate)). The method has broad applicability and can be used to produce multifunctional imprinted nanoparticles with potential for further application in the biosensors, diagnostics and biomedical fields and as an alternative to natural receptors. PMID:23503559

Computational and experimental investigation of molecular imprinted polymers for selective extraction of dimethoate and its metabolite omethoate from olive oil.

PubMed

Bakas, Idriss; Oujji, Najwa Ben; Moczko, Ewa; Istamboulie, Georges; Piletsky, Sergey; Piletska, Elena; Ait-Addi, Elhabib; Ait-Ichou, Ihya; Noguer, Thierry; Rouillon, Régis

2013-01-25

This work presents the development of molecularly imprinted polymers (MIPs) for the selective extraction of dimethoate from olive oil. Computational simulations allowed selecting itaconic acid as the monomer showing the highest affinity towards dimethoate. Experimental validation confirmed modelling predictions and showed that the polymer based on IA as functional monomer and omethoate as template molecule displays the highest selectivity for the structurally similar pesticides dimethoate, omethoate and monocrotophos. Molecularly imprinted solid phase extraction (MISPE) method was developed and applied to the clean-up of olive oil extracts. It was found that the most suitable solvents for loading, washing and elution step were respectively hexane, hexane-dichloromethane (85:15%) and methanol. The developed MIPSE was successfully applied to extraction of dimethoate from olive oil, with recovery rates up to 94%. The limits of detection and quantification of the described method were respectively 0.012 and 0.05 μg g(-1). Copyright © 2012 Elsevier B.V. All rights reserved.

Development of molecularly imprinted polymers to block quorum sensing and inhibit bacterial biofilm formation.

PubMed

Ma, Luyao; Feng, Shaolong; de la Fuente-Nunez, Cesar; Hancock, Robert E W; Lu, Xiaonan

2018-05-16

Bacterial biofilms are responsible for most clinical infections and show increased antimicrobial resistance. In this study, molecularly imprinted polymers (MIPs) were developed to specifically capture prototypical quorum sensing autoinducers [i.e., N-(3-oxododecanoyl)-L-homoserine lactone (3-oxo-C12AHL)], interrupt quorum sensing, and subsequently inhibit biofilm formation of Pseudomonas aeruginosa, an important human nosocomial pathogen. The synthesis of MIPs was optimized by considering the amount and type of the functional monomers itaconic acid (IA) and 2-hydroxyethyl methacrylate (HEMA). IA-based MIPs showed high adsorption affinity towards 3-oxo-C12AHL with an imprinting factor of 1.68. Compared to IA-based MIPs, the adsorption capacity of HEMA-based MIPs was improved 5-fold. HEMA-based MIPs significantly reduced biofilm formation (by ~65%), while biofilm suppression by IA-based MIPs was neutralized due to increased bacterial attachment. The developed MIPs represent promising alternative biofilm intervention agents that can be applied to surfaces relevant to clinical settings and food processing equipment.

New molecular imprinted voltammetric sensor for determination of ochratoxin A.

PubMed

Yola, Mehmet Lütfi; Gupta, Vinod Kumar; Atar, Necip

2016-04-01

In this report, a novel molecular imprinted voltammetric sensor based on silver nanoparticles (AgNPs) involved in a polyoxometalate (H3PW12O40, POM) functionalized reduced graphene oxide (rGO) modified glassy carbon electrode (GCE) was presented for determination of ochrattoxin A (OCH). The developed surfaces were characterized using scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD) method. OCH imprinted GCE was prepared via electropolymerization process of 100mM phenol as monomer in the presence of phosphate buffer solution (pH6.0) containing 25 mM OCH. The linearity range and the detection limit of the method were calculated as 5.0 × 10(-11) - 1.5 × 10(-9)M and 1.6 × 10(-11) M, respectively. The voltammetric sensor was applied to grape juice and wine samples with good selectivity and recovery. The stability of the voltammetric sensor was also reported. Copyright © 2015 Elsevier B.V. All rights reserved.

Molecular Dynamics Simulation Study of the Selectivity of a Silica Polymer for Ibuprofen

PubMed Central

Concu, Riccardo; Cordeiro, M. Natalia D. S.

2016-01-01

In the past few years, the sol-gel polycondensation technique has been increasingly employed with great success as an alternative approach to the preparation of molecularly imprinted materials (MIMs). The main aim of this study was to study, through a series of molecular dynamics (MD) simulations, the selectivity of an imprinted silica xerogel towards a new template—the (±)-2-(P-Isobutylphenyl) propionic acid (Ibuprofen, IBU). We have previously demonstrated the affinity of this silica xerogel toward a similar molecule. In the present study, we simulated the imprinting process occurring in a sol-gel mixture using the Optimized Potentials for Liquid Simulations-All Atom (OPLS-AA) force field, in order to evaluate the selectivity of this xerogel for a template molecule. In addition, for the first time, we have developed and verified a new parameterisation for the Ibuprofen® based on the OPLS-AA framework. To evaluate the selectivity of the polymer, we have employed both the radial distribution functions, interaction energies and cluster analyses. PMID:27399685

Molecular Dynamics Simulation Study of the Selectivity of a Silica Polymer for Ibuprofen.

PubMed

Concu, Riccardo; Cordeiro, M Natalia D S

2016-07-07

In the past few years, the sol-gel polycondensation technique has been increasingly employed with great success as an alternative approach to the preparation of molecularly imprinted materials (MIMs). The main aim of this study was to study, through a series of molecular dynamics (MD) simulations, the selectivity of an imprinted silica xerogel towards a new template-the (±)-2-(P-Isobutylphenyl) propionic acid (Ibuprofen, IBU). We have previously demonstrated the affinity of this silica xerogel toward a similar molecule. In the present study, we simulated the imprinting process occurring in a sol-gel mixture using the Optimized Potentials for Liquid Simulations-All Atom (OPLS-AA) force field, in order to evaluate the selectivity of this xerogel for a template molecule. In addition, for the first time, we have developed and verified a new parameterisation for the Ibuprofen(®) based on the OPLS-AA framework. To evaluate the selectivity of the polymer, we have employed both the radial distribution functions, interaction energies and cluster analyses.

LncRNA/DNA binding analysis reveals losses and gains and lineage specificity of genomic imprinting in mammals.

PubMed

Liu, Haihua; Shang, Xiaoxiao; Zhu, Hao

2017-05-15

Genomic imprinting is regulated by lncRNAs and is important for embryogenesis, physiology and behaviour in mammals. Aberrant imprinting causes diseases and disorders. Experimental studies have examined genomic imprinting primarily in humans and mice, thus leaving some fundamental issues poorly addressed. The cost of experimentally examining imprinted genes in many tissues in diverse species makes computational analysis of lncRNAs' DNA binding sites valuable. We performed lncRNA/DNA binding analysis in imprinting clusters from multiple mammalian clades and discovered the following: (i) lncRNAs and imprinting sites show significant losses and gains and distinct lineage-specificity; (ii) binding of lncRNAs to promoters of imprinted genes may occur widely throughout the genome; (iii) a considerable number of imprinting sites occur in only evolutionarily more derived species; and (iv) multiple lncRNAs may bind to the same imprinting sites, and some lncRNAs have multiple DNA binding motifs. These results suggest that the occurrence of abundant lncRNAs in mammalian genomes makes genomic imprinting a mechanism of adaptive evolution at the epigenome level. The data and program are available at the database LongMan at lncRNA.smu.edu.cn. zhuhao@smu.edu.cn. Supplementary data are available at Bioinformatics online. © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com

Pharmacological extension of the sensitive period for imprinting in Gallus domesticus.

PubMed

Parsons, C H; Rogers, L J

1997-12-01

Precocial animals, such as the chick, exhibit a form of learning termed filial imprinting. The chick's sensitive period for filial imprinting is restricted to the first few days after hatching. The neural mechanism that terminates the sensitive period is not fully understood. It is thought to be an experience-dependent event because once a chick has imprinted, it will not readily imprint on another stimulus. However, even dark-reared chicks eventually lose the ability to imprint, which suggests that the ending of the sensitive period may not be entirely experience-dependent. The present study investigates factors that may contribute to the ending of the sensitive period. In our experiments, dark-reared chicks were unable to imprint after Day 2 posthatching, but chicks treated 10 h after hatching with an intramuscular injection of the noncompetitive N-methyl-D-aspartate (NMDA) receptor antagonist ketamine (55 mg/kg) and the alpha2-adrenoceptor agonist xylazine (6 mg/kg) (KX) imprinted on a stuffed hen 8 days after hatching. Similarly treated chicks did not imprint on a red and black box, although the box was an effective imprinting stimulus for Day 2 chicks. Chicks treated with KX at 20 or 40 h posthatching or on Day 4 or 7 as well as controls treated with pyrogen-free saline were unable to imprint on Day 8.

Potential roles for transposable elements in creating imprinted expression.

PubMed

Anderson, Sarah N; Springer, Nathan M

2018-04-01

Changes in gene expression can have profound effects on phenotype. Nature has provided many complex patterns of gene regulation such as imprinting. Imprinted genes exhibit differences in the expression of the maternal and paternal alleles, even though they reside in the same nucleus with access to the same trans-acting factors. Significant attention has been focused on the potential reasons that imprinted expression could be beneficial and stabilized by selection. However, less attention has focused on understanding how imprinted expression might arise or decay. We discuss the evidence for frequent turnover of imprinted expression based on evolutionary analyses in plants and the potential role for transposable elements (TEs) in creating imprinted expression patterns. Copyright © 2018 Elsevier Ltd. All rights reserved.

Imprinting can cause a maladaptive preference for infectious conspecifics.

PubMed

Stephenson, Jessica F; Reynolds, Michael

2016-04-01

Recognizing and associating with specific individuals, such as conspecifics or kin, brings many benefits. One mechanism underlying such recognition is imprinting: the long-term memory of cues encountered during development. Typically, juveniles imprint on cues of nearby individuals and may later associate with phenotypes matching their 'recognition template'. However, phenotype matching could lead to maladaptive social decisions if, for instance, individuals imprint on the cues of conspecifics infected with directly transmitted diseases. To investigate the role of imprinting in the sensory ecology of disease transmission, we exposed juvenile guppies,Poecilia reticulata, to the cues of healthy conspecifics, or to those experiencing disease caused by the directly transmitted parasite Gyrodactylus turnbulli In a dichotomous choice test, adult 'disease-imprinted' guppies preferred to associate with the chemical cues of G. turnbulli-infected conspecifics, whereas 'healthy-imprinted' guppies preferred to associate with cues of uninfected conspecifics. These responses were only observed when stimulus fish were in late infection, suggesting imprinted fish responded to cues of disease, but not of infection alone. We discuss how maladaptive imprinting may promote disease transmission in natural populations of a social host. © 2016 The Author(s).

Role of imprint cytology in intra operative diagnosis of thyroid lesions.

PubMed

Anila, K R; Krishna, G

2014-07-01

Intra-operative imprint cytology is an important diagnostic modality in the diagnosis of thyroid lesions. A correct intra-operative diagnosis helps eliminate the need for second surgery. To study diagnostic accuracy of imprint cytology and to compare the imprint cytology results with that of the corresponding paraffin section diagnosis in thyroidectomy cases. This is a prospective study of 84 patients who have undergone thyroidectomies over a period of one year at the Department of Surgery, Thiruvananthapuram, Kerala, India. The intraoperative imprint cytology smears were stained by Papanicolaou method. The imprint cytology interpretation was later compared with the paraffin section diagnosis. Of the 84 patients using haematoxylin and eosin stained histopathology sections as the gold standard, the diagnostic sensitivity of imprint cytology was 75% and specificity was 100%. Positive predictive value was 100%. Negative predictive value was 98.74%. Imprint cytology has high sensitivity and specificity in diagnosing lesions of the thyroid. The problems faced were in diagnosing follicular carcinomas and differentiating low grade lymphoma from lymphocytic thyroiditis. Imprint cytology is a simple, reliable diagnostic technique. It has high sensitivity and specificity in intra-operative diagnosis of lesions of thyroid. In spite of the advent of newer diagnostic modalities like frozen sections, imprint cytology still holds its unique position in the current perspective.

Sexual imprinting on ecologically divergent traits leads to sexual isolation in sticklebacks

PubMed Central

Kozak, Genevieve M.; Head, Megan L.; Boughman, Janette W.

2011-01-01

During sexual imprinting, offspring learn parental phenotypes and then select mates who are similar to their parents. Imprinting has been thought to contribute to the process of speciation in only a few rare cases; this is despite imprinting's potential to generate assortative mating and solve the problem of recombination in ecological speciation. If offspring imprint on parental traits under divergent selection, these traits will then be involved in both adaptation and mate preference. Such ‘magic traits’ easily generate sexual isolation and facilitate speciation. In this study, we show that imprinting occurs in two ecologically divergent stickleback species (benthics and limnetics: Gasterosteus spp.). Cross-fostered females preferred mates of their foster father's species. Furthermore, imprinting is essential for sexual isolation between species; isolation was reduced when females were raised without fathers. Daughters imprinted on father odour and colour during a critical period early in development. These traits have diverged between the species owing to differences in ecology. Therefore, we provide the first evidence that imprinting links ecological adaptation to sexual isolation between species. Our results suggest that imprinting may facilitate the evolution of sexual isolation during ecological speciation, may be especially important in cases of rapid diversification, and thus play an integral role in the generation of biodiversity. PMID:21270044

Sexual imprinting on ecologically divergent traits leads to sexual isolation in sticklebacks.

PubMed

Kozak, Genevieve M; Head, Megan L; Boughman, Janette W

2011-09-07

During sexual imprinting, offspring learn parental phenotypes and then select mates who are similar to their parents. Imprinting has been thought to contribute to the process of speciation in only a few rare cases; this is despite imprinting's potential to generate assortative mating and solve the problem of recombination in ecological speciation. If offspring imprint on parental traits under divergent selection, these traits will then be involved in both adaptation and mate preference. Such 'magic traits' easily generate sexual isolation and facilitate speciation. In this study, we show that imprinting occurs in two ecologically divergent stickleback species (benthics and limnetics: Gasterosteus spp.). Cross-fostered females preferred mates of their foster father's species. Furthermore, imprinting is essential for sexual isolation between species; isolation was reduced when females were raised without fathers. Daughters imprinted on father odour and colour during a critical period early in development. These traits have diverged between the species owing to differences in ecology. Therefore, we provide the first evidence that imprinting links ecological adaptation to sexual isolation between species. Our results suggest that imprinting may facilitate the evolution of sexual isolation during ecological speciation, may be especially important in cases of rapid diversification, and thus play an integral role in the generation of biodiversity.

NMDA receptor antagonists extend the sensitive period for imprinting.

PubMed

Parsons, C H; Rogers, L J

2000-03-01

Filial imprinting in the domestic chick occurs during a sensitive period of development. The exact timing of this period can vary according to the methods used to measure imprinting. Using our imprinting paradigm, we have shown that normal, dark-reared chicks lose the ability to imprint after the second day post-hatching. Further, we reported that chicks treated 10 h after hatching with a mixture of the noncompetitive NMDA receptor antagonist ketamine (55 mg/kg) and the alpha(2)-adrenergic receptor agonist xylazine (6 mg/kg) were able to imprint on day 8 after hatching, whereas controls treated with saline did not imprint. We now show that the effect of the ketamine-xylazine mixture can be mimicked by treating chicks with ketamine alone or with another noncompetitive NMDA receptor antagonist, MK-801 (5 mg/kg). Treating chicks with a single dose of ketamine (55 mg/kg) or with a single dose of xylazine (6 mg/kg) failed to produce the effect on the sensitive period. However, prolonging the action of ketamine by treating chicks with two doses of ketamine (at 10 and 12 h after hatching) did allow imprinting on day 8. In contrast, prolonging the action of xylazine had no effect on the sensitive period for imprinting. Chicks treated with MK-801 were also able to imprint on day 8. Thus, we have evidence that the NMDA receptor system is involved in the mechanisms that control the sensitive period for imprinting.

Social Functioning and Adjustment in Chinese Children: The Imprint of Historical Time

ERIC Educational Resources Information Center

Chen, Xinyin; Cen, Guozhen; Li, Dan; He, Yunfeng

2005-01-01

This study examined, in 3 cohorts (1990, 1998, and 2002) of elementary school children (M age10 years), relations between social functioning and adjustment in different phases of the societal transition in China. Data were obtained from multiple sources. The results indicate that sociability-cooperation was associated with peer acceptance and…

Seed development and genomic imprinting in plants.

PubMed

Köhler, Claudia; Grossniklaus, Ueli

2005-01-01

Genomic imprinting refers to an epigenetic phenomenon where the activity of an allele depends on its parental origin. Imprinting at individual genes has only been described in mammals and seed plants. We will discuss the role imprinted genes play in seed development and compare the situation in plants with that in mammals. Interestingly, many imprinted genes appear to control cell proliferation and growth in both groups of organisms although imprinting in plants may also be involved in the cellular differentiation of the two pairs of gametes involved in double fertilization. DNA methylation plays some role in the control of parent-of-origin-specific expression in both mammals and plants. Thus, although imprinting evolved independently in mammals and plants, there are striking similarities at the phenotypic and possibly also mechanistic level.

Dissecting genomic imprinting and genetic conflict from a game theory prospective. Comment on: ;Epigenetic game theory: How to compute the epigenetic control of maternal-to-zygotic transition; by Qian Wang et al.

NASA Astrophysics Data System (ADS)

Cui, Yuehua; Yang, Haitao

2017-03-01

Epigenetics typically refers to changes in the structure of a chromosome that affect gene activity and expression. Genomic imprinting is a special type of epigenetic phenomenon in which the expression of an allele depends on its parental origin. When an allele inherited from the mother (or father) is imprinted (i.e., silent), it is termed as maternal (or paternal) imprinting. Imprinting is often resulted from DNA methylation and tends to cluster together in the genome [1]. It has been shown to play a key role in many genetic disorders in humans [2]. Imprinting is heritable and undergoes a reprogramming process in gametes before and after fertilization [1]. Sometimes the reprogramming process is not reversible, leading to the loss of imprinting [3]. Although efforts have been made to experimentally or computationally infer imprinting genes, the underlying molecular mechanism that leads to unbalanced allelic expression is still largely unknown.

Loss of the imprinted snoRNA mbii-52 leads to increased 5htr2c pre-RNA editing and altered 5HT2CR-mediated behaviour.

PubMed

Doe, Christine M; Relkovic, Dinko; Garfield, Alastair S; Dalley, Jeffrey W; Theobald, David E H; Humby, Trevor; Wilkinson, Lawrence S; Isles, Anthony R

2009-06-15

The Prader-Willi syndrome (PWS) genetic interval contains several brain-expressed small nucleolar (sno)RNA species that are subject to genomic imprinting. In vitro studies have shown that one of these snoRNA molecules, h/mbii-52, negatively regulates editing and alternative splicing of the serotonin 2C receptor (5htr2c) pre-RNA. However, the functional consequences of loss of h/mbii-52 and subsequent increased post-transcriptional modification of 5htr2c are unknown. 5HT2CRs are important in controlling aspects of cognition and the cessation of feeding, and disruption of their function may underlie some of the psychiatric and feeding abnormalities seen in PWS. In a mouse model for PWS lacking expression of mbii-52 (PWS-IC+/-), we show an increase in editing, but not alternative splicing, of the 5htr2c pre-RNA. This change in post-transcriptional modification is associated with alterations in a number of 5HT2CR-related behaviours, including impulsive responding, locomotor activity and reactivity to palatable foodstuffs. In a non-5HT2CR-related behaviour, marble burying, loss of mbii-52 was without effect. The specificity of the behavioural effects to changes in 5HT2CR function was further confirmed using drug challenges. These data illustrate, for the first time, the physiological consequences of altered RNA editing of 5htr2c linked to mbii-52 loss that may underlie specific aspects of the complex PWS phenotype and point to an important functional role for this imprinted snoRNA.

Development of a Molecularly Imprinted Polymer-Based Sensor for the Electrochemical Determination of Triacetone Triperoxide (TATP)

PubMed Central

Mamo, Samuel Kassahun; Gonzalez-Rodriguez, Jose

2014-01-01

The explosive triacetone triperoxide (TATP), which can be prepared from commercially readily available reagents following an easy synthetic procedure, is one of the most common components of improvised explosive devices (IEDs). Molecularly-imprinted polymer (MIP) electrochemical sensors have proved useful for the determination of different compounds in different matrices with the required sensitivity and selectivity. In this work, a highly sensitive and selective molecularly imprinted polymer with electrochemical capabilities for the determination of TATP has been developed. The molecular imprinting has been performed via electropolymerisation onto a glassy carbon electrode surface by cyclic voltammetry from a solution of pyrrole functional monomer, TATP template and LiClO4. Differential Pulse Voltammetry of TATP, with LiClO4 as supporting electrolyte, was performed in a potential range of −2.0 V to +1.0 V (vs. Ag/AgCl). Three-factor two-level factorial design was used to optimise the monomer concentration at 0.1 mol·L−1, template concentration at 100 mmol·L−1 and the number of cyclic voltammetry scan cycles to 10. The molecularly imprinted polymer-modified glassy carbon electrode demonstrated good performance at low concentrations for a linear range of 82–44,300 μg·L−1 and a correlation coefficient of r2 = 0.996. The limits of detection (LoD) and quantification (LoQ) achieved were 26.9 μg·L−1 and 81.6 μg·L−1, respectively. The sensor demonstrated very good repeatability with precision values (n = 6, expressed as %RSD) of 1.098% and 0.55% for 1108 and 2216 μg·L−1, respectively. It also proved selective for TATP in the presence of other explosive substances such as PETN, RDX, HMX, and TNT. PMID:25490589

Elevated expression of brain-derived neurotrophic factor facilitates visual imprinting in chicks.

PubMed

Suzuki, Keiko; Maekawa, Fumihiko; Suzuki, Shingo; Nakamori, Tomoharu; Sugiyama, Hayato; Kanamatsu, Tomoyuki; Tanaka, Kohichi; Ohki-Hamazaki, Hiroko

2012-12-01

With the aim of elucidating the neural mechanisms of early learning, we studied the role of brain-derived neurotrophic factor (BDNF) in visual imprinting in birds. The telencephalic neural circuit connecting the visual Wulst and intermediate medial mesopallium is critical for imprinting, and the core region of the hyperpallium densocellulare (HDCo), situated at the center of this circuit, has a key role in regulating the activity of the circuit. We found that the number of BDNF mRNA-positive cells in the HDCo was elevated during the critical period, particularly at its onset, on the day of hatching (P0). After imprinting training on P1, BDNF mRNA-positive cells in the HDCo increased in number, and tyrosine phosphorylation of TrkB was observed. BDNF infusion into the HDCo at P1 induced imprinting, even with a weak training protocol that does not normally induce imprinting. In contrast, K252a, an antagonist of Trk, inhibited imprinting. Injection of BDNF at P7, after the critical period, did not elicit imprinting. These results suggest that BDNF promotes the induction of imprinting through TrkB exclusively during the critical period. © 2012 The Authors Journal of Neurochemistry © 2012 International Society for Neurochemistry.

Effects of imprint training procedure at birth on the reactions of foals at age six months.

PubMed

Williams, J L; Friend, T H; Collins, M N; Toscano, M J; Sisto-Burt, A; Nevill, C H

2003-03-01

While imprint training procedures have been promoted in popular magazines, they have received limited scientific investigation. To determine the effects of a neonatal imprint training procedure on 6-month-old foals and to determine if any one session had a greater effect than others. Foals (n = 131) were divided into the following treatments: no imprint training, imprint training at birth, 12, 24 and 48 h after birth or imprint training only at birth, 12, 24, 48, or 72 h after birth. Foals then received minimal human handling until they were tested at 6 months. During training, time to complete exposure to the stimulus was significant for only 2 of 6 stimuli. Percentage change in baseline heart rate was significant for only 2 of 10 stimuli. These 4 effects were randomly spread across treatments. Neither the number of imprint training sessions (0, 1, or 4) nor the timing of imprint training sessions (none, birth, 12, 24, 48, or 72 h after birth) influenced the foal's behaviour at 6 months of age. In this study, imprint training did not result in better behaved, less reactive foals.

Smart coumarin-tagged imprinted polymers for the rapid detection of tamoxifen.

PubMed

Ray, Judith V; Mirata, Fosca; Pérollier, Celine; Arotcarena, Michel; Bayoudh, Sami; Resmini, Marina

2016-03-01

A signalling molecularly imprinted polymer was synthesised for easy detection of tamoxifen and its metabolites. 6-Vinylcoumarin-4-carboxylic acid (VCC) was synthesised from 4-bromophenol to give a fluorescent monomer, designed to switch off upon binding of tamoxifen. Clomiphene, a chlorinated analogue, was used as the template for the imprinting, and its ability to quench the coumarin fluorescence when used in a 1:1 ratio was demonstrated. Tamoxifen and 4-hydroxytamoxifen were also shown to quench coumarin fluorescence. Imprinted and non-imprinted polymers were synthesised using VCC, methacrylic acid as a backbone monomer and ethylene glycol dimethacrylate as cross-linker, and were ground and sieved to particle sizes ranging between 45 and 25 μm. Rebinding experiments demonstrate that the imprinted polymer shows very strong affinity for both clomiphene and tamoxifen, while the non-imprinted polymer shows negligible rebinding. The fluorescence of the imprinted polymer is quenched by clomiphene, tamoxifen and 4-hydroxytamoxifen. The switch off in fluorescence of the imprinted polymer under these conditions could also be detected under a UV lamp with the naked eye, making this matrix suitable for applications when coupled with a sample preparation system.

Copy number rather than epigenetic alterations are the major dictator of imprinted methylation in tumors.

PubMed

Martin-Trujillo, Alex; Vidal, Enrique; Monteagudo-Sa Nchez, Ana; Sanchez-Delgado, Marta; Moran, Sebastian; Hernandez Mora, Jose Ramon; Heyn, Holger; Guitart, Miriam; Esteller, Manel; Monk, David

2017-09-07

It has been postulated that imprinting aberrations are common in tumors. To understand the role of imprinting in cancer, we have characterized copy-number and methylation in over 280 cancer cell lines and confirm our observations in primary tumors. Imprinted differentially methylated regions (DMRs) regulate parent-of-origin monoallelic expression of neighboring transcripts in cis. Unlike single-copy CpG islands that may be prone to hypermethylation, imprinted DMRs can either loose or gain methylation during tumorigenesis. Here, we show that methylation profiles at imprinted DMRs often not represent genuine epigenetic changes but simply the accumulation of underlying copy-number aberrations (CNAs), which is independent of the genome methylation state inferred from cancer susceptible loci. Our results reveal that CNAs also influence allelic expression as loci with copy-number neutral loss-of-heterozygosity or amplifications may be expressed from the appropriate parental chromosomes, which is indicative of maintained imprinting, although not observed as a single expression foci by RNA FISH.Altered genomic imprinting is frequently reported in cancer. Here, the authors analyze copy number and methylation in cancer cell lines and primary tumors to show that imprinted methylation profiles represent the accumulation of copy number alteration, rather than epigenetic alterations.

Microgravity

NASA Image and Video Library

1997-01-12

1 mm histone octamer crystal grown on STS-81. A very dynamic structure which functions in many aspects of gene regulation from control of gene activity to the more subtle mechanisms of genetic imprinting. Principle Investigator is Dan Carter of New Century Pharmaceuticals.

The amino-terminal structure of human fragile X mental retardation protein obtained using precipitant-immobilized imprinted polymers

NASA Astrophysics Data System (ADS)

Hu, Yufeng; Chen, Zhenhang; Fu, Yanjun; He, Qingzhong; Jiang, Lun; Zheng, Jiangge; Gao, Yina; Mei, Pinchao; Chen, Zhongzhou; Ren, Xueqin

2015-03-01

Flexibility is an intrinsic property of proteins and essential for their biological functions. However, because of structural flexibility, obtaining high-quality crystals of proteins with heterogeneous conformations remain challenging. Here, we show a novel approach to immobilize traditional precipitants onto molecularly imprinted polymers (MIPs) to facilitate protein crystallization, especially for flexible proteins. By applying this method, high-quality crystals of the flexible N-terminus of human fragile X mental retardation protein are obtained, whose absence causes the most common inherited mental retardation. A novel KH domain and an intermolecular disulfide bond are discovered, and several types of dimers are found in solution, thus providing insights into the function of this protein. Furthermore, the precipitant-immobilized MIPs (piMIPs) successfully facilitate flexible protein crystal formation for five model proteins with increased diffraction resolution. This highlights the potential of piMIPs for the crystallization of flexible proteins.

Physiological mechanisms of imprinting and homing migration in Pacific salmon Oncorhynchus spp.

PubMed

Ueda, H

2012-07-01

After several years of feeding at sea, salmonids have an amazing ability to migrate long distances from the open ocean to their natal stream to spawn. Three different research approaches from behavioural to molecular biological studies have been used to elucidate the physiological mechanisms underpinning salmonid imprinting and homing migration. The study was based on four anadromous Pacific salmon Oncorhynchus spp., pink salmon Oncorhynchus gorbuscha, chum salmon Oncorhynchus keta, sockeye salmon Oncorhynchus nerka and masu salmon Oncorhynchus masou, migrating from the North Pacific Ocean to the coast of Hokkaido, Japan, as well as lacustrine O. nerka and O. masou in Lake Toya, Hokkaido, where the lake serves as the model oceanic system. Behavioural studies using biotelemetry techniques showed swimming profiles from the Bering Sea to the coast of Hokkaido in O. keta as well as homing behaviours of lacustrine O. nerka and O. masou in Lake Toya. Endocrinological studies on hormone profiles in the brain-pituitary-gonad axis of O. keta, and lacustrine O. nerka identified the hormonal changes during homing migration. Neurophysiological studies revealed crucial roles of olfactory functions on imprinting and homing during downstream and upstream migration, respectively. These findings are discussed in relation to the physiological mechanisms of imprinting and homing migration in anadromous and lacustrine salmonids. © 2012 The Author. Journal of Fish Biology © 2012 The Fisheries Society of the British Isles.

Implementation of molecularly imprinted polymer beads for surface enhanced Raman detection.

PubMed

Kamra, Tripta; Zhou, Tongchang; Montelius, Lars; Schnadt, Joachim; Ye, Lei

2015-01-01

Molecularly imprinted polymers (MIPs) have a predesigned molecular recognition capability that can be used to build robust chemical sensors. MIP-based chemical sensors allow label-free detection and are particularly interesting due to their simple operation. In this work we report the use of thiol-terminated MIP microspheres to construct surfaces for detection of a model organic analyte, nicotine, by surface enhanced Raman scattering (SERS). The nicotine-imprinted microspheres are synthesized by RAFT precipitation polymerization and converted into thiol-terminated microspheres through aminolysis. The thiol groups on the MIP surface allow the microspheres to be immobilized on a gold-coated substrate. Three different strategies are investigated to achieve surface enhanced Raman scattering in the vicinity of the imprinted sites: (1) direct sputtering of gold nanoparticles, (2) immobilization of gold colloids through the MIP's thiol groups, and (3) trapping of the MIP microspheres in a patterned SERS substrate. For the first time we show that large MIP microspheres can be turned into selective SERS surfaces through the three different approaches of assembly. The MIP-based sensing surfaces are used to detect nicotine to demonstrate the proof of concept. As synthesis and surface functionalization of MIP microspheres and nanoparticles are well established, the methods reported in this work are handy and efficient for constructing label-free chemical sensors, in particular for those based on SERS detection.

Fabrication and evaluation of magnetic/hollow double-shelled imprinted sorbents formed by Pickering emulsion polymerization.

PubMed

Pan, Jianming; Li, Linzi; Hang, Hui; Wu, Runrun; Dai, Xiaohui; Shi, Weidong; Yan, Yongsheng

2013-06-25

Magnetic/hollow double-shelled imprinted polymers (MH-MIPs) were synthesized by Pickering emulsion polymerization. In this method, attapulgite (ATP) particles were used as stabilizers to establish a stable oil-in-water emulsion, and a few hydrophilic Fe3O4 nanoparticles were allowed to be magnetic separation carriers. The imprinting system was fabricated by radical polymerization in the presence of the functional and polymeric monomers in the oil phase. The results of characterization indicated that MH-MIPs exhibited magnetic sensitivity (Ms = 4.76 emu g(-1)), thermal stability (especially below 200 °C), and hollow structure and were composed of exterior ATP shells and interior imprinted polymers shells. Then MH-MIPs were evaluated as sorbents for the selective binding of λ-cyhalothrin as a result of their magnetism, enhanced mechanical strength, hydrophilic surface, and recognition ability. The kinetic properties of MH-MIPs were well described by the pseudo-second-order equation, indicating that the chemical process could be the rate-limiting step in the adsorption process for λ-cyhalothrin. The equilibrium adsorption capacity of MH-MIPs was 60.06 μmol g(-1) at 25 °C, and the Langmuir isotherm model gave a better fit to the experimental data, indicating the monolayer molecular adsorption for λ-cyhalothrin. The selective recognition experiments also demonstrated the high affinity and selectivity of MH-MIIPs toward λ-cyhalothrin over fenvalerate and diethyl phthalate.

Selective extraction of bisphenol A from water by one-monomer molecularly imprinted magnetic nanoparticles.

PubMed

Lin, Zhenkun; Zhang, Yanfang; Su, Yu; Qi, Jinxia; Jia, Yinhang; Huang, Changjiang; Dong, Qiaoxiang

2018-01-15

One-monomer molecularly imprinted magnetic nanoparticles were prepared as adsorbents for selective extraction of bisphenol A from water in this study. A single bi-functional monomer was adopted for preparation of the molecularly imprinted polymer, avoiding the tedious trial-and-error optimizations as traditional strategy. Moreover, bisphenol F was used as the dummy template for bisphenol A to avoid the interference from residual template molecules. These nanoparticles showed not only large adsorption capacity and good selectivity to the bisphenol A but also outstanding magnetic response performance. Furthermore, they were successfully used as magnetic solid-phase extraction adsorbents of bisphenol A from various water samples, including tap water, river water, and seawater. The developed method was found to be much more efficient, convenient, and economical for selective extraction of bisphenol A compared with the traditional solid-phase extraction. Separation of these nanoparticles can be easily achieved with an external magnetic field, and the optimized adsorption time was only 15 min. The recoveries of bisphenol A in different water samples ranged from 85.38 to 93.75%, with relative standard deviation lower than 7.47%. These results showed that one-monomer molecularly imprinted magnetic nanoparticles had the potential to be popular adsorbents for selective extraction of pollutants from water. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Molecularly imprinted polymers coated on multi-walled carbon nanotubes through a simple indirect method for the determination of 2,4-dichlorophenoxyacetic acid in environmental water

NASA Astrophysics Data System (ADS)

Yang, Weijie; Jiao, Feipeng; Zhou, Lei; Chen, Xiaoqing; Jiang, Xinyu

2013-11-01

A new and facile method was presented to graft molecularly imprinted polymers (MIPs) on carbon nanotubes (CNTs) for 2,4-dichlorophenoxyacetic acid (2,4-D) analysis. In brief, CNTs were firstly coated with a layer of vinyl group modified silica, followed by a common precipitation polymerization with 2,4-D as the template, ethylene glycol dimethacrylate (EGDMA) as the crosslinker and 2,2-azobisisobutyronitrile (AIBN) as the initiator. The imprinted effects obtained by using different monomers were investigated, and the results showed that acrylamide (AM) and styrene as mixed monomers was the best choice. This functionalized material was characterized by Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM) and thermogravimetry (TG), which demonstrated a successful polymerization reaction on CNTs with MIPs grafting ratio of about 80%. The results of static adsorption experiments indicated the imprinted material possessed fast kinetics and good selectivity for 2,4-D molecules. A corresponding analytical method was developed and demonstrated to be applicable for the determination of 2,4-D in environmental water. The recoveries were in the range from 74.6% to 81.2% with relative standard deviation below 7.0%. To be emphasized, the method for MIPs coating proposed herein also provides a significant reference for other radical polymerization reactions based on CNTs.

Strategies of molecular imprinting-based fluorescence sensors for chemical and biological analysis.

PubMed

Yang, Qian; Li, Jinhua; Wang, Xiaoyan; Peng, Hailong; Xiong, Hua; Chen, Lingxin

2018-07-30

One pressing concern today is to construct sensors that can withstand various disturbances for highly selective and sensitive detecting trace analytes in complicated samples. Molecularly imprinted polymers (MIPs) with tailor-made binding sites are preferred to be recognition elements in sensors for effective targets detection, and fluorescence measurement assists in highly sensitive detection and user-friendly control. Accordingly, molecular imprinting-based fluorescence sensors (MI-FL sensors) have attracted great research interest in many fields such as chemical and biological analysis. Herein, we comprehensively review the recent advances in MI-FL sensors construction and applications, giving insights on sensing principles and signal transduction mechanisms, focusing on general construction strategies for intrinsically fluorescent or nonfluorescent analytes and improvement strategies in sensing performance, particularly in sensitivity. Construction strategies are well overviewed, mainly including the traditional indirect methods of competitive binding against pre-bound fluorescent indicators, employment of fluorescent functional monomers and embedding of fluorescence substances, and novel rational designs of hierarchical architecture (core-shell/hollow and mesoporous structures), post-imprinting modification, and ratiometric fluorescence detection. Furthermore, MI-FL sensor based microdevices are discussed, involving micromotors, test strips and microfluidics, which are more portable for rapid point-of-care detection and in-field diagnosing. Finally, the current challenges and future perspectives of MI-FL sensors are proposed. Copyright © 2018 Elsevier B.V. All rights reserved.

Determination of fusaric acid in maize using molecularly imprinted SPE clean-up

USDA-ARS?s Scientific Manuscript database

A new liquid chromatography method to detect fusaric acid in maize is reported based on molecularly imprinted polymer solid phase extraction clean-up (MISPE) using mimic-templated molecularly-imprinted polymers. Picolinic acid was used as a toxin analog for imprinting polymers during a thermolytic s...

Rational computational design for the development of andrographolide molecularly imprinted polymer

NASA Astrophysics Data System (ADS)

Krishnan, Hemavathi; Islam, K. M. Shafiqul; Hamzah, Zainab; Ahmad, Mohd Noor

2017-10-01

Andrographolide is a popular medicinal compound derived from Andrographis Paniculata (AP). Molecularly Imprint Polymer (MIP) is a "Lock and Key" approach, where MIP is the lock and Andrographolide is the key which fits to the MIP lock by both physically and chemically. MIP will be used as selective extraction tool to enrich Andrographolide bioactive compound. Pre-polymerization step is crucial to design MIP. This work investigates molecular interactions and the Gibbs free binding energies on the development of MIP. The structure of Andrographolide (template) and functional monomers were drawn in HyperChem 8.0.10. A hybrid quantum chemical model was used with a few functional monomers. Possible conformations of template and functional monomer as 1:n (n < 4) were designed and simulated to geometrically optimize the complex to the lowest energy in gas phase. The Gibbs free binding energies of each conformation were calculated using semi-empirical PM3 simulation method. Results proved that functional monomers that contain carboxylic group shows higher binding energy compared to those with amine functional group. Itaconic acid (IA) chosen as the best functional monomer at optimum ratio (1:3) of template: monomer to prepare andrographolide MIP. This study demonstrates the importance of studying intermolecular interaction among template, functional monomer and template-monomer ratio in developing MIP.

"Two-dimensional" molecularly imprinted solid-phase extraction coupled with crystallization and high performance liquid chromatography for fast semi-preparative purification of tannins from pomegranate husk extract.

PubMed

Sun, Guangying; Liu, Yanfang; Ahat, Hasanjan; Shen, Aijin; Liang, Xinmiao; Xue, Xingya; Luo, Yuqin; Yang, Jian; Liu, Zhao-Sheng; Aisa, Haji Akber

2017-07-07

In this study, "two dimensional" molecularly imprinted solid-phase extraction (2D-MIP-SPE) of semi-preparative grade was constructed to fast purify ellagitannins in pomegranate husk extract with the help of crystallization and reverse-phase liquid chromatgoraphy (RPLC). Ellagic acid and punicalagin imprinted polymers were synthesized in batch mode and two semi-preparative MIP-SPE columns were individually packed. After investigaing "functional complementation", 2D-MIP-SPE was constructed using ellagic acid MIP and punicalagin MIP-SPE as the first and second dimension, respectively. Then, pomegranate husk extract was fast divided into four fractions individually enriching in ellagic acid, granatin A, punicalagin and ellagic acid glucoside by 2D-MIP-SPE. With the aid of crystallization and RPLC, ellagic acid (13.5mg) and punicalagin (53.4mg) were fast obtained in 30min. Ellagic acid glucoside was purified to the purity near 100% with a recovery of 86.1%. Granatin A (92%) was directly obtained by 2D-MIP-SPE with the recovery of 81.8%. All above indicated that 2D-MIP-SPE was highly efficient in natural product purification. The concept of "functional complementation" was expected to be a useful tool in the construction of 2D-MIP-SPE. Copyright © 2017 Elsevier B.V. All rights reserved.

Computational Aided-Molecular Imprinted Polymer Design for Solid Phase Extraction of Metaproterenol from Plasma and Determination by Voltammetry Using Modified Carbon Nanotube Electrode

PubMed Central

Ahmadi, Farhad; Karamian, Ehsan

2014-01-01

A molecular imprinted polymer (MIP) was computationally designed and synthesized for the selective extraction of metaproterenol (MTP), from human plasma. In this regards semi empirical MP3 and mechanical quantum (DFT) calculations were used to find a suitable functional monomers. On the basis of computational and experimental results, acrylic acid (AA) and DMSO:MeOH (90:10 %V/V) were found to be the best choices of functional monomer and polymerization solvents, respectively. This polymer was then used as a selective sorbent to develop a molecularly imprinted solid-phase extraction (MISPE) procedure followed by differential pulse voltammetry by using modified carbon nanotube electrode. The analysis was performed in phosphate buffer, pH 7.0. Peak currents were measured at +0.67 V versus Ag/AgCl. The linear calibration range was 0.026–8.0 μg mL-1 with a limit of detection 0.01 μg mL-1. The relative standard deviation at 0.5 μg mL-1 was 4.76% (n=5). The mean recoveries of 5 μg mL-1 MTP from plasma was 92.2% (n=5). The data of MISPE-DPV were compared with the MISPE-HPLC-UV. Although, the MISPE-DPV was more sensitive but both techniques have similar accuracy and precision. PMID:25237337

Synthesis of a specific monolithic column with artificial recognition sites for L-glutamic acid via cryo-crosslinking of imprinted nanoparticles.

PubMed

Göktürk, Ilgım; Üzek, Recep; Uzun, Lokman; Denizli, Adil

2016-06-01

In this study, a new molecular imprinting (MIP)-based monolithic cryogel column was prepared using chemically crosslinked molecularly imprinted nanoparticles, to achieve a simplified chromatographic separation (SPE) for a model compound, L-glutamic acid (L-Glu). Cryogelation through crosslinking of imprinted nanoparticles forms stable monolithic cryogel columns. This technique reduces the leakage of nanoparticles and increases the surface area, while protecting the structural features of the cryogel for stable and efficient recognition of the template molecule. A non-imprinted monolithic cryogel column (NIP) was also prepared, using non-imprinted nanoparticles produced without the addition of L-Glu during polymerization. The molecularly imprinted monolithic cryogel column (MIP) indicates apparent recognition selectivity and a good adsorption capacity compared to the NIP. Also, we have achieved a significant increase in the adsorption capacity, using the advantage of high surface area of the nanoparticles.

[Werkgartner's muzzle imprint mark--a literature study].

PubMed

Geserick, Gunther; Vendura, Klaus; Wirth, Ingo

2009-01-01

Since Werkgartner described and correctly interpreted the muzzle imprint mark around the gunshot entrance wound in 1922, this finding has been generally accepted as a sign of a contact shot. In further studies, it could finally be clarified that the muzzle imprint mark is caused by the expansive power of the powder gases with pressure on and abrasion of the skin at the muzzle (weapon imprint). Its shape depends on the firearm, the ammunition and the anatomical conditions, but does not require a bullet. Examinations under a magnifying glass microscope and histological investigations can complete the macroscopic findings. Occasionally, the muzzle imprint mark requires a certain "drying period" in order to become clearly visible. In rare cases, muzzle imprint marks also form on textiles perforated by the projectile. Characteristically shaped muzzled imprint marks can provide clues to the type of the firearm and its position at the time of discharge.

Current Progress of Nanomaterials in Molecularly Imprinted Electrochemical Sensing.

PubMed

Zhong, Chunju; Yang, Bin; Jiang, Xinxin; Li, Jianping

2018-01-02

Nanomaterials have received much attention during the past decade because of their excellent optical, electronic, and catalytic properties. Nanomaterials possess high chemical reactivity, also high surface energy. Thus, provide a stable immobilization platform for biomolecules, while preserving their reactivity. Due to the conductive and catalytic properties, nanomaterials can also enhance the sensitivity of molecularly imprinted electrochemical sensors by amplifying the electrode surface, increasing the electron transfer, and catalyzing the electrochemical reactions. Molecularly imprinted polymers that contain specific molecular recognition sites can be designed for a particular target analyte. Incorporating nanomaterials into molecularly imprinted polymers is important because nanomaterials can improve the response signal, increase the sensitivity, and decrease the detection limit of the sensors. This study describes the classification of nanomaterials in molecularly imprinted polymers, their analytical properties, and their applications in the electrochemical sensors. The progress of the research on nanomaterials in molecularly imprinted polymers and the application of nanomaterials in molecularly imprinted polymers is also reviewed.

77 FR 64775 - New Mailing Standards for Domestic Mailing Services Products

Federal Register 2010, 2011, 2012, 2013, 2014

2012-10-23

... imprint to report identical weight pieces on PS Form 3606, Certificate of Bulk Mailing. For January 2013... by permit imprint to also pay for the fees by permit imprint. Delivery Confirmation We would revise... to the old Confirm service. Picture Permit Imprint Indicia Effective June 24, 2012, the Postal...

Influence of hydrogen bond accepting ability of anions on the adsorption performance of ionic liquid surface molecularly imprinted polymers.

PubMed

Zhu, Guifen; Gao, Xia; Wang, Xiaolong; Wang, Jianji; Fan, Jing

2018-01-12

To illuminate the influence mechanism of anionic structure of ionic liquids (ILs) on the adsorption performance of surface molecularly imprinted polymers (MIPs), in this work, six newly designed MIPs were prepared on the surface of amino-poly(styrene-divinylbenzene) particles by using imidazolium ILs with the same cation [C 4 mim] + but different anions (Cl, CH 3 SO 3 , PF 6 , BF 4 , C 4 F 7 O 2 , C 4 F 9 SO 3 ) as template molecules, methacrylic acid as functional monomer, and ethylene dimethacrylate as cross-linker. The resulting MIP materials were characterized by IR and SEM, and the influence of hydrogen bond accepting ability of anions on the adsorption performance of the MIPs for the ILs was investigated in acetonitrile. It was found that adsorption capacity of the MIPs towards the ILs decreased in the order MIP [C4mim][Cl]  > MIP [C4mim][C4F7O2]  ≥ MIP [C4mim][BF4] and MIP [C4mim][CH3SO3]  > MIP [C4mim][C4F9SO3]  > MIP [C4mim][PF6] , which is in good agreement with the ability of anions of the ILs to form hydrogen bonds. Ultraviolet, 1 H-NMR and 35 Cl-NMR spectroscopy was then used to study the interactions of anions of the ILs with the functional monomer. It was found that the hydrogen bond interaction between anions of the ILs and acidic proton of the functional monomer was the main driving force for the high adsorption selectivity of the imprinted polymers, and the stronger hydrogen bond interaction indicates higher binding capacity and higher selectivity of the polymers towards the ILs. It was also verified that the ILs with stronger hydrogen bond accepting ability of anions could be selectively extracted by the corresponding IL-MIPs. These results may provide new insight into the recognition mechanism of MIPs for ILs, and are also useful for the rational design of this new class of imprinting materials. Copyright © 2017 Elsevier B.V. All rights reserved.

The evolution of genomic imprinting: theories, predictions and empirical tests

PubMed Central

Patten, M M; Ross, L; Curley, J P; Queller, D C; Bonduriansky, R; Wolf, J B

2014-01-01

The epigenetic phenomenon of genomic imprinting has motivated the development of numerous theories for its evolutionary origins and genomic distribution. In this review, we examine the three theories that have best withstood theoretical and empirical scrutiny. These are: Haig and colleagues' kinship theory; Day and Bonduriansky's sexual antagonism theory; and Wolf and Hager's maternal–offspring coadaptation theory. These theories have fundamentally different perspectives on the adaptive significance of imprinting. The kinship theory views imprinting as a mechanism to change gene dosage, with imprinting evolving because of the differential effect that gene dosage has on the fitness of matrilineal and patrilineal relatives. The sexual antagonism and maternal–offspring coadaptation theories view genomic imprinting as a mechanism to modify the resemblance of an individual to its two parents, with imprinting evolving to increase the probability of expressing the fitter of the two alleles at a locus. In an effort to stimulate further empirical work on the topic, we carefully detail the logic and assumptions of all three theories, clarify the specific predictions of each and suggest tests to discriminate between these alternative theories for why particular genes are imprinted. PMID:24755983

Defect reduction of patterned media templates and disks

NASA Astrophysics Data System (ADS)

Luo, Kang; Ha, Steven; Fretwell, John; Ramos, Rick; Ye, Zhengmao; Schmid, Gerard; LaBrake, Dwayne; Resnick, Douglas J.; Sreenivasan, S. V.

2010-05-01

Imprint lithography has been shown to be an effective technique for the replication of nano-scale features. Acceptance of imprint lithography for manufacturing will require a demonstration of defect levels commensurate with cost-effective device production. This work summarizes the results of defect inspections of hard disks patterned using Jet and Flash Imprint Lithography (J-FILTM). Inspections were performed with optical based automated inspection tools. For the hard drive market, it is important to understand the defectivity of both the template and the imprinted disk. This work presents a methodology for automated pattern inspection and defect classification for imprint-patterned media. Candela CS20 and 6120 tools from KLA-Tencor map the optical properties of the disk surface, producing highresolution grayscale images of surface reflectivity and scattered light. Defects that have been identified in this manner are further characterized according to the morphology. The imprint process was tested after optimizing both the disk cleaning and adhesion layers processes that precede imprinting. An extended imprint run was performed and both the defect types and trends are reported.

Molecularly Imprinted Polymer of Colocynthin, An Effective Tool for Quality Control of Citrullus colocynthis Extracts.

PubMed

Farid, Ramezani; Mahnaz, Khanavi; Ardekani Mohammad Reza, Shams; Börje, Sellergren; Mahdieh, Eftekhari; Hossein, Rastegar; Maryam, Shekarchi

2017-01-01

Different parts of Colocynth, Citrullus colocynthis (L.) Schrad., are used in traditional phytotherapy and homeopathy. In our new approach, a molecularly imprinted polymer was synthesized to absorb colocynthin, the major plant marker, and its capability was evaluated using HPLC-UV. A new method was considered to achieve optimal conditions. FT-infrared, N2 adsorption porosimetry, fluorescent and scanning electron microscopy and thermo gravimetric profile of the polymers were studied. The imprinted polymer was applied as molecularly imprinted solid phase extraction sorbent to enrich colocynthin from colocynth oil extract, a traditional medicine dosage form. The imprinted polymer showed high capacity and affinity toward colocynthin. Physical assessments demonstrated no major differences between imprinted and nonimprinted polymers. The imprinted polymer was able to absorb colocynthin more efficiently than non-imprinted and control simple solvent extraction from the real sample. In conclusion, this polymer is capable of being applied as a promising adsorbent for analysis of colocynth traditional medicine products. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Preparation of mixed molecularly imprinted polymer magnetic nanoparticles and its application in separation of Chinese traditional medicine

NASA Astrophysics Data System (ADS)

Xie, Yihui; Ma, Yajuan; Bai, Wenting; Zhu, Xiaofang; Liu, Min; Huang, Liping

2017-08-01

A mixed imprinted polymer which can rapidly adsorb all flavonoids from raspberry extract was prepared and recycled. The hybrid molecular surface imprinted polymers were prepared by using quercetin as the template molecule and Fe3O4 magnetic nanospheres as the carrier. The molecular imprinting polymer was prepared by using the "initial template molecule, molecularly imprinted polymer, mixed template molecule, molecularly imprint ted polymers (MIPS)". The adsorption performance and durability of the hybrid molecularly imprinted polymers were investigated by using the fingerprints of the ethyl acetate fraction of raspberry as an index. The adsorption of flavonoids from raspberry extract, lindenoside, cis-lindenin, quercetin, kaempferol and other flavonoids was completely adsorbed by mixed molecular-imprinted polymer, and the other components were basically adsorbed. When Mix-IMPs were repeatedly used 10 times, the fingerprints showed that the content and content of flavonoids were basically the same. The experimental results show that Mix-IMPs has good adsorption performance, can be recycled and used for rapid enrichment of flavonoids in raspberry.

Molecularly imprinted titania nanoparticles for selective recognition and assay of uric acid

NASA Astrophysics Data System (ADS)

Mujahid, Adnan; Khan, Aimen Idrees; Afzal, Adeel; Hussain, Tajamal; Raza, Muhammad Hamid; Shah, Asma Tufail; uz Zaman, Waheed

2015-06-01

Molecularly imprinted titania nanoparticles are su ccessfully synthesized by sol-gel method for the selective recognition of uric acid. Atomic force microscopy is used to study the morphology of uric acid imprinted titania nanoparticles with diameter in the range of 100-150 nm. Scanning electron microscopy images of thick titania layer indicate the formation of fine network of titania nanoparticles with uniform distribution. Molecular imprinting of uric acid as well as its subsequent washing is confirmed by Fourier transformation infrared spectroscopy measurements. Uric acid rebinding studies reveal the recognition capability of imprinted particles in the range of 0.01-0.095 mmol, which is applicable in monitoring normal to elevated levels of uric acid in human blood. The optical shift (signal) of imprinted particles is six times higher in comparison with non-imprinted particles for the same concentration of uric acid. Imprinted titania particles have shown substantially reduced binding affinity toward interfering and structurally related substances, e.g. ascorbic acid and guanine. These results suggest the possible application of titania nanoparticles in uric acid recognition and quantification in blood serum.

Imprinting Disorders and Assisted Reproductive Technology

PubMed Central

Owen, Carter M.; Segars, James H.

2009-01-01

Worldwide use of assisted reproductive technology (ART) accounts for an estimated 1 to 3% of births. Since 2002, a series of reports have suggested an increased risk of imprinting disorders (Beckwith-Wiedemann syndrome and Angelman syndrome) in children conceived by ART. Definitive conclusions are difficult to substantiate due to the rarity of imprinting disorders and the variability in ART protocols. Despite these limitations, there is biological plausibility for alteration in nongenomic inheritance caused by ART. Animal studies have shown that ART procedures can alter normal imprinting, specifically DNA methylation patterns. Collectively, studies suggest an association between ART and loss of maternal methylation. More recent reports examined a possible association between ART and global hypomethylation of DNA. Three other imprinting disorders (Silver-Russell syndrome, maternal hypomethylation syndrome, and retinoblastoma) have also been implicated, but there is insufficient evidence to establish an association of these syndromes with ART. Based on current evidence, the absolute risk of imprinting disorders after ART remains small and does not warrant routine screening. Large prospective studies are needed to better understand the risks associated with imprinting disorders, imprinting defects, and ART. PMID:19711252

Imprinted gene expression in fetal growth and development.

PubMed

Lambertini, L; Marsit, C J; Sharma, P; Maccani, M; Ma, Y; Hu, J; Chen, J

2012-06-01

Experimental studies showed that genomic imprinting is fundamental in fetoplacental development by timely regulating the expression of the imprinted genes to overlook a set of events determining placenta implantation, growth and embryogenesis. We examined the expression profile of 22 imprinted genes which have been linked to pregnancy abnormalities that may ultimately influence childhood development. The study was conducted in a subset of 106 placenta samples, overrepresented with small and large for gestational age cases, from the Rhode Island Child Health Study. We investigated associations between imprinted gene expression and three fetal development parameters: newborn head circumference, birth weight, and size for gestational age. Results from our investigation show that the maternally imprinted/paternally expressed gene ZNF331 inversely associates with each parameter to drive smaller fetal size, while paternally imprinted/maternally expressed gene SLC22A18 directly associates with the newborn head circumference promoting growth. Multidimensional Scaling analysis revealed two clusters within the 22 imprinted genes which are independently associated with fetoplacental development. Our data suggest that cluster 1 genes work by assuring cell growth and tissue development, while cluster 2 genes act by coordinating these processes. Results from this epidemiologic study offer solid support for the key role of imprinting in fetoplacental development. Copyright © 2012 Elsevier Ltd. All rights reserved.

Controlled Vectorial Electron Transfer and Photoelectrochemical Applications of Layered Relay/Photosensitizer-Imprinted Au Nanoparticle Architectures on Electrodes.

PubMed

Metzger, Tzuriel S; Tel-Vered, Ran; Willner, Itamar

2016-03-23

Two configurations of molecularly imprinted bis-aniline-bridged Au nanoparticles (NPs) for the specific binding of the electron acceptor N,N'-dimethyl-4,4'-bipyridinium (MV(2+) ) and for the photosensitizer Zn(II)-protoporphyrin IX (Zn(II)-PP-IX) are assembled on electrodes, and the photoelectrochemical features of the two configurations are discussed. Configuration I includes the MV(2+) -imprinted Au NPs matrix as a base layer, on which the Zn(II)-PP-IX-imprinted Au NPs layer is deposited, while configuration II consists of a bilayer corresponding to the reversed imprinting order. Irradiation of the two electrodes in the presence of a benzoquinone/benzohydroquinone redox probe yields photocurrents of unique features: (i) Whereas configuration I yields an anodic photocurrent, the photocurrent generated by configuration II is cathodic. (ii) The photocurrents obtained upon irradiation of the imprinted electrodes are substantially higher as compared to the nonimprinted surfaces. The high photocurrents generated by the imprinted Au NPs-modified electrodes are attributed to the effective loading of the imprinted matrices with the MV(2+) and Zn(II)-PP-IX units and to the effective charge separation proceeding in the systems. The directional anodic/cathodic photocurrents are rationalized in terms of vectorial electron transfer processes dictated by the imprinting order and by the redox potentials of the photosensitizer/electron acceptor units associated with the imprinted sites in the two configurations. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Surface Imprints: Advantageous Application of Ready2use Materials for Bacterial Quartz-Crystal Microbalance Sensors.

PubMed

Poller, Anna-Maria; Spieker, Eva; Lieberzeit, Peter A; Preininger, Claudia

2017-01-11

Four different materials (two ab initio synthesized polyurethanes; ready-to-use: Epon1002F and poly(vinyl alcohol)/N-methyl-4(4'-formylstyryl)pyridinium methosulfate acetal) for the generation of Escherichia coli surface imprints are compared in this work. The use of commercially available, ready-to-use materials instead of self-synthesized polymers represents an innovative and convenient way of molecular imprint fabrication. This was herein investigated for large, biological templates. Fully synthesized imprint materials (polyurethanes) were developed and optimized regarding their OH excess and the use of catalyst in the polymerization reaction. No to low OH excess (0-10%) and a noncatalyzed synthesis were determined to be superior for the imprinting of the Gram-negative bacteria. Imprints were characterized using atomic force microscopy, with Epon1002F yielding the most distinguished imprints, along with a smooth surface. The imprints were afterward tested as plastic antibody coatings in a mass-sensitive quartz-crystal microbalance measurement. Dilutions of E. coli suspensions, down to a limit of detection of 1.4 × 10 7 CFU/mL, were successfully measured. Best results were obtained with Epon1002F and self-synthesized, stoichiometric polyurethane. Since ready-to-use Epon1002F was superior in terms of signal intensities and sensitivity, it can advantageously replace self-synthesized polymers for the generation of imprinted sensor surfaces. Easy day-to-day reproducibility and further shortening of imprint fabrication time are other advantages of employing the ready-to-use material instead of conventionally synthesized polymers.

Characterization of the differentially methylated region of the Impact gene that exhibits Glires-specific imprinting.

PubMed

Okamura, Kohji; Wintle, Richard F; Scherer, Stephen W

2008-01-01

Imprinted genes are exclusively expressed from one of the two parental alleles in a parent-of-origin-specific manner. In mammals, nearly 100 genes are documented to be imprinted. To understand the mechanism behind this gene regulation and to identify novel imprinted genes, common features of DNA sequences have been analyzed; however, the general features required for genomic imprinting have not yet been identified, possibly due to variability in underlying molecular mechanisms from locus to locus. We performed a thorough comparative genomic analysis of a single locus, Impact, which is imprinted only in Glires (rodents and lagomorphs). The fact that Glires and primates diverged from each other as recent as 70 million years ago makes comparisons between imprinted and non-imprinted orthologues relatively reliable. In species from the Glires clade, Impact bears a differentially methylated region, whereby the maternal allele is hypermethylated. Analysis of this region demonstrated that imprinting was not associated with the presence of direct tandem repeats nor with CpG dinucleotide density. In contrast, a CpG periodicity of 8 bp was observed in this region in species of the Glires clade compared to those of carnivores, artiodactyls, and primates. We show that tandem repeats are dispensable, establishment of the differentially methylated region does not rely on G+C content and CpG density, and the CpG periodicity of 8 bp is meaningful to the imprinting. This interval has recently been reported to be optimal for de novo methylation by the Dnmt3a-Dnmt3L complex, suggesting its importance in the establishment of imprinting in Impact and other genes.

Role of imprint/exfoliative cytology in ulcerated skin neoplasms.

PubMed

Ramakrishnaiah, Vishnu Prasad Nelamangala; Babu, Ravindra; Pai, Dinker; Verma, Surendra Kumar

2013-12-01

Imprint cytology is a method of studying cells by taking an imprint from the cut surface of a wedge biopsy specimen or from the resected margins of a surgical specimen. It is rapid, simple and fairly accurate. Exfoliative cytology is an offshoot from the imprint cytology where in cells obtained from the surface of ulcers, either by scrape or brush, are analyzed for the presence of malignant cells. We undertook this study to see the role of imprint/exfoliative cytology in the diagnosis of ulcerated skin neoplasm and to check the adequacy of resected margins intra-operatively. This was a prospective investigative study conducted from September 2003 to July 2005. All patients presenting to surgical clinic with ulcerated skin and soft tissue tumours were included in the study. A wedge biopsy obtained from the ulcer and imprint smears were taken from the cut surface. Exfoliative cytology was analyzed from the surface smears. Wedge biopsy specimen was sent for histopathological (HPE) examination. The cytology and HPE were analyzed by a separate pathologist. Imprint cytology was also used to check the adequacy of resected margins in case of wide excision. This was compared with final HPE. Total of 107 patients was included in the present study and 474 imprint smears were done, with an average of 4.43 slides per lesion. Out of 59 wide excision samples, 132 imprint smears were prepared for assessing resected margins accounting for an average of 2.24 slides per each excised lesion. On combining imprint cytology with exfoliative cytology the overall sensitivity, specificity and positive predictive value were 90.38 %, 100 % and 90.38 % respectively. Only one out of 59 cases had a positive resected margin which was not picked by imprint cytology. Imprint cytology can be used for rapid and accurate diagnosis of various skin malignancies. It can also be used to check the adequacy of the resected margin intraoperatively.

Selectivity mapping of the binding sites of (E)-resveratrol imprinted polymers using structurally diverse polyphenolic compounds present in Pinot noir grape skins.

PubMed

Hashim, Shima N N S; Schwarz, Lachlan J; Danylec, Basil; Potdar, Mahesh K; Boysen, Reinhard I; Hearn, Milton T W

2016-12-01

This investigation describes a general procedure for the selectivity mapping of molecularly imprinted polymers, using (E)-resveratrol-imprinted polymers as the exemplar, and polyphenolic compounds present in Pinot noir grape skin extracts as the test compounds. The procedure is based on the analysis of samples generated before and after solid-phase extraction of (E)-resveratrol and other polyphenols contained within the Pinot noir grape skins using (E)-resveratrol-imprinted polymers. Capillary reversed-phase high-performance liquid chromatography (RP-HPLC) and electrospray ionisation tandem mass spectrometry (ESI MS/MS) was then employed for compound analysis and identification. Under optimised solid-phase extraction conditions, the (E)-resveratrol-imprinted polymer showed high binding affinity and selectivity towards (E)-resveratrol, whilst no resveratrol was bound by the corresponding non-imprinted polymer. In addition, quercetin-3-O-glucuronide and a dimer of catechin-methyl-5-furfuraldehyde, which share some structural features with (E)-resveratrol, were also bound by the (E)-resveratrol-imprinted polymer. Polyphenols that were non-specifically retained by both the imprinted and non-imprinted polymer were (+)-catechin, a B-type procyanidin and (-)-epicatechin. The compounds that did not bind to the (E)-resveratrol molecularly imprinted polymer had at least one of the following molecular characteristics in comparison to the (E)-resveratrol template: (i) different spatial arrangements of their phenolic hydroxyl groups, (ii) less than three or more than four phenolic hydroxyl groups, or (iii) contained a bulky substituent moiety. The results show that capillary RP-HPLC in conjunction with ESI MS/MS represent very useful techniques for mapping the selectivity of the binding sites of imprinted polymer. Moreover, this procedure permits performance monitoring of the characteristics of molecularly imprinted polymers intended for solid-phase extraction of bioactive and nutraceutical molecules from diverse agricultural waste sources. Copyright © 2016 Elsevier B.V. All rights reserved.

Polymorphic Imprinting of SLC38A4 Gene in Bovine Placenta.

PubMed

Xu, Da; Zhang, Cui; Li, Junliang; Wang, Guannan; Chen, Weina; Li, Dongjie; Li, Shijie

2018-05-21

Imprinted genes are characterized by monoallelic expression that is dependent on parental origin. Comparative analysis of imprinted genes between species is a powerful tool for understanding the biological significance of genomic imprinting. The slc38a4 gene encodes a neutral amino acid transporter and is identified as imprinted in mice. In this study, the imprinting status of SLC38A4 was assessed in bovine adult tissues and placenta using a polymorphism-based approach. Results indicate that SLC38A4 is not imprinted in eight adult bovine tissues including heart, liver, spleen, lung, kidney, muscle, fat, and brain. It was interesting to note that SLC38A4 showed polymorphic status in five heterogeneous placentas, with three exhibiting paternal monoallelic expression and two exhibiting biallelic expression. Monoallelic expression of imprinted genes is generally associated with allele-specific differentially methylation regions (DMRs) of CpG islands (CGIs)-encompassed promoter; therefore, the DNA methylation statuses of three CGIs in the SLC38A4 promoter and exon 1 region were tested in three placentas (two exhibiting paternal monoallelic and one showing biallelic expression of SLC38A4) and their corresponding paternal sperms. Unexpectedly, extreme hypomethylation (< 3%) of the DNA was observed in all the three detected placentas and their corresponding paternal sperms. The absence of DMR in bovine SLC38A4 promoter region implied that DNA methylation of these three CGIs does not directly or indirectly affect the polymorphic imprinting of SLC38A4 in bovine placenta. This suggested other epigenetic features other than DNA methylation are needed in regulating the imprinting of bovine SLC38A4, which is different from that of mouse with respect to a DMR existence at the mouse's slc38a4 promoter region. Although further work is needed, this first characterization of polymorphic imprinting status of SLC38A4 in cattle placenta provides valuable information on investigating the genomic imprinting phenomenon itself.

The development of 8 inch roll-to-plate nanoimprint lithography (8-R2P-NIL) system

NASA Astrophysics Data System (ADS)

Lee, Lai Seng; Mohamed, Khairudin; Ooi, Su Guan

2017-07-01

Growth in semiconductor and integrated circuit industry was observed in the past decennium of years for industrial technology which followed Moore's law. The line width of nanostructure to be exposed was influenced by the essential technology of photolithography. Thus, it is crucial to have a low cost and high throughput manufacturing process for nanostructures. Nanoimprint Lithography technique invented by Stephen Y. Chou was considered as major nanolithography process to be used in future integrated circuit and integrated optics. The drawbacks of high imprint pressure, high imprint temperature, air bubbles formation, resist sticking to mold and low throughput of thermal nanoimprint lithography on silicon wafer have yet to be solved. Thus, the objectives of this work is to develop a high throughput, low imprint force, room temperature UV assisted 8 inch roll to plate nanoimprint lithography system capable of imprinting nanostructures on 200 mm silicon wafer using roller imprint with flexible mold. A piece of resist spin coated silicon wafer was placed onto vacuum chuck drives forward by a stepper motor. A quartz roller wrapped with a piece of transparent flexible mold was used as imprint roller. The imprinted nanostructures were cured by 10 W, 365 nm UV LED which situated inside the quartz roller. Heat generated by UV LED was dissipated by micro heat pipe. The flexible mold detaches from imprinted nanostructures in a 'line peeling' pattern and imprint pressure was measured by ultra-thin force sensors. This system has imprinting speed capability ranging from 0.19 mm/s to 5.65 mm/s, equivalent to imprinting capability of 3 to 20 pieces of 8 inch wafers per hour. Speed synchronization between imprint roller and vacuum chuck was achieved by controlling pulse rate supplied to stepper motor which drive the vacuum chuck. The speed different ranging from 2 nm/s to 98 nm/s is achievable. Vacuum chuck height was controlled by stepper motor with displacement of 5 nm/step.

A new accurate pill recognition system using imprint information

NASA Astrophysics Data System (ADS)

Chen, Zhiyuan; Kamata, Sei-ichiro

2013-12-01

Great achievements in modern medicine benefit human beings. Also, it has brought about an explosive growth of pharmaceuticals that current in the market. In daily life, pharmaceuticals sometimes confuse people when they are found unlabeled. In this paper, we propose an automatic pill recognition technique to solve this problem. It functions mainly based on the imprint feature of the pills, which is extracted by proposed MSWT (modified stroke width transform) and described by WSC (weighted shape context). Experiments show that our proposed pill recognition method can reach an accurate rate up to 92.03% within top 5 ranks when trying to classify more than 10 thousand query pill images into around 2000 categories.

Loss of imprinting at the Dlk1-Gtl2 locus caused by insertional mutagenesis in the Gtl2 5' region

PubMed Central

Steshina, Ekaterina Y; Carr, Michael S; Glick, Elena A; Yevtodiyenko, Aleksey; Appelbe, Oliver K; Schmidt, Jennifer V

2006-01-01

Background The Dlk1 and Gtl2 genes define a region of mouse chromosome 12 that is subject to genomic imprinting, the parental allele-specific expression of a gene. Although imprinted genes play important roles in growth and development, the mechanisms by which imprinting is established and maintained are poorly understood. Differentially methylated regions (DMRs), which carry methylation on only one parental allele, are involved in imprinting control at many loci. The Dlk1-Gtl2 region contains three known DMRs, the Dlk1 DMR in the 3' region of Dlk1, the intergenic DMR 15 kb upstream of Gtl2, and the Gtl2 DMR at the Gtl2 promoter. Three mouse models are analyzed here that provide new information about the regulation of Dlk1-Gtl2 imprinting. Results A previously existing insertional mutation (Gtl2lacZ), and a targeted deletion in which the Gtl2 upstream region was replaced by a Neo cassette (Gtl2Δ5'Neo), display partial lethality and dwarfism upon paternal inheritance. Molecular characterization shows that both mutations cause loss of imprinting and changes in expression of the Dlk1, Gtl2 and Meg8/Rian genes. Dlk1 levels are decreased upon paternal inheritance of either mutation, suggesting Dlk1 may be causative for the lethality and dwarfism. Loss of imprinting on the paternal chromosome in both Gtl2lacZ and Gtl2Δ5'Neo mice is accompanied by the loss of paternal-specific Gtl2 DMR methylation, while maternal loss of imprinting suggests a previously unknown regulatory role for the maternal Gtl2 DMR. Unexpectedly, when the Neo gene is excised, Gtl2Δ5' animals are of normal size, imprinting is unchanged and the Gtl2 DMR is properly methylated. The exogenous DNA sequences integrated upstream of Gtl2 are therefore responsible for the growth and imprinting effects. Conclusion These data provide further evidence for the coregulation of the imprinted Dlk1 and Gtl2 genes, and support a role for Dlk1 as an important neonatal growth factor. The ability of the Gtl2lacZ and Gtl2Δ5'Neo mutations to cause long-range changes in imprinting and gene expression suggest that regional imprinting regulatory elements may lie in proximity to the integration site. PMID:17014736

Using IMPRINT to Guide Experimental Design with Simulated Task Environments

DTIC Science & Technology

2015-06-18

USING IMPRINT TO GUIDE EXPERIMENTAL DESIGN OF SIMULATED TASK ENVIRONMENTS THESIS Gregory...ENG-MS-15-J-052 USING IMPRINT TO GUIDE EXPERIMENTAL DESIGN WITH SIMULATED TASK ENVIRONMENTS THESIS Presented to the Faculty Department...Civilian, USAF June 2015 DISTRIBUTION STATEMENT A. APPROVED FOR PUBLIC RELEASE; DISTRIBUTION UNLIMITED. AFIT-ENG-MS-15-J-052 USING IMPRINT

21 CFR 330.3 - Imprinting of solid oral dosage form drug products.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 5 2010-04-01 2010-04-01 false Imprinting of solid oral dosage form drug products... AS SAFE AND EFFECTIVE AND NOT MISBRANDED General Provisions § 330.3 Imprinting of solid oral dosage form drug products. A requirement to imprint an identification code on solid oral dosage form drug...

77 FR 50932 - Electronic Transmission of Customs Data-Outbound International Letter-Post Items

Federal Register 2010, 2011, 2012, 2013, 2014

2012-08-23

... mailpieces bearing a customs declaration form when the items are paid with a permit imprint. DATES: Effective...[supreg] items bearing a permit imprint at a business mail entry unit (BMEU) since the information... Imprint--General [Revise 243.3 to read as follows:] Mailers may use a permit imprint for mailing identical...

77 FR 64768 - International Mailing Services: Proposed Product and Price Changes

Federal Register 2010, 2011, 2012, 2013, 2014

2012-10-23

... flexibility for mailers who pay for postage with a permit imprint, to now pay the fee using the same permit imprint account. Previously, the only option to pay the fee was for mailers to apply ordinary stamps, meter imprints, or PC Postage[supreg] imprints to PS Form 3877, Firm Mailing Book for Accountable Mail...

21 CFR 330.3 - Imprinting of solid oral dosage form drug products.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 5 2011-04-01 2011-04-01 false Imprinting of solid oral dosage form drug products... AS SAFE AND EFFECTIVE AND NOT MISBRANDED General Provisions § 330.3 Imprinting of solid oral dosage form drug products. A requirement to imprint an identification code on solid oral dosage form drug...

Analysis of alternariol and alternariol monomethyl ether in foodstuffs by molecularly imprinted solid-phase extraction and ultra-high-performance liquid chromatography tandem mass spectrometry.

PubMed

Rico-Yuste, A; Walravens, J; Urraca, J L; Abou-Hany, R A G; Descalzo, A B; Orellana, G; Rychlik, M; De Saeger, S; Moreno-Bondi, M C

2018-03-15

Molecularly imprinted porous polymer microspheres selective to Alternaria mycotoxins, alternariol (AOH) and alternariol monomethyl ether (AME), were synthesized and applied to the extraction of both mycotoxins in food samples. The polymer was prepared using 4-vinylpiridine (VIPY) and methacrylamide (MAM) as functional monomers, ethylene glycol dimethacrylate (EDMA) as cross-linker and 3,8,9-trihydroxy-6H-dibenzo[b,d]pyran-6-one (S2) as AOH surrogate template. A molecularly imprinted solid phase extraction (MISPE) method has been optimized for the selective isolation of the mycotoxins from aqueous samples coupled to HPLC with fluorescence (λ ex =258nm; λ em =440nm) or MS/MS analysis. The MISPE method was validated by UPLC-MS/MS for the determination of AOH and AME in tomato juice and sesame oil based on the European Commission Decision 2002/657/EC. Method performance was satisfactory with recoveries from 92.5% to 106.2% and limits of quantification within the 1.1-2.8µgkg -1 range in both samples. Copyright © 2017 Elsevier Ltd. All rights reserved.

Magnetic molecularly imprinted polymer for the selective extraction of quercetagetin from Calendula officinalis extract.

PubMed

Ma, Run-Tian; Shi, Yan-Ping

2015-03-01

A new magnetic molecularly imprinted polymers (MMIPs) for quercetagetin was prepared by surface molecular imprinting method using super paramagnetic core-shell nanoparticle as the supporter. Acrylamide as the functional monomer, ethyleneglycol dimethacrylate as the crosslinker and acetonitrile as the porogen were applied in the preparation process. Fourier transform infrared spectrometer (FT-IR), X-ray diffraction (XRD) and Vibrating sample magnetometer (VSM) were applied to characterize the MMIPs, and High performance liquid chromatography (HPLC) was utilized to analyze the target analytes. The selectivity of quercetagetin MMIPs was evaluated according to their recognition to template and its analogues. Excellent binding for quercetagetin was observed in MMIPs adsorption experiment, and the adsorption isotherm models analysis showed that the homogeneous binding sites were distributed on the surface of the MMIPs. The MMIPs were employed as adsorbents in solid phase extraction for the determination of quercetagetin in Calendula officinalis extracts. Furthermore, this method is fast, simple and could fulfill the determination and extraction of quercetagetin from herbal extract. Copyright © 2014 Elsevier B.V. All rights reserved.

Synthesis of a molecularly imprinted polymer for the selective recognition of carmoisine (Azorubin E122) from pomegranate juice.

PubMed

Ghasempour, Zahra; Alizadeh-Khaledabad, Mohammad; Vardast, Mohammad-Reza; Rezazad-Bari, Mahmoud

2017-02-01

Since natural pigments are lost during the processing of beverages such as pomegranate juice, carmoisine, as an adulterant, is often added into the pure juice to improve color characteristics. In this study, molecularly imprinted polymers, as an adsorbent of carmoisine, were synthesized using acrylamide, methacrylic acid, and 4-vinylpyridine as functional monomers and then they were evaluated in terms of the separation and detection of carmoisine. Experiments on the batch adsorption of carmoisine 10 ppm stock solution revealed a better binding capacity for the 4-vinylpyridine-based polymer in comparison to methacrylic acid and acrylamide polymers. The complexation of carmoisine with the 4-vinylpyridine-based polymer was confirmed by Fourier transform infrared spectroscopy. The synthesized polymer exerted a high thermal degradation point and average diameter of polymer particles were obtained to be 0.2 μm by dynamic light scattering analysis. This work showed that detection of pomegranate juice adulteration with carmoisine is not necessarily difficult, time consuming or expensive with selective separation techniques such as molecularly imprinted polymers. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Molecular Imprinting Technology in Quartz Crystal Microbalance (QCM) Sensors.

PubMed

Emir Diltemiz, Sibel; Keçili, Rüstem; Ersöz, Arzu; Say, Rıdvan

2017-02-24

Molecularly imprinted polymers (MIPs) as artificial antibodies have received considerable scientific attention in the past years in the field of (bio)sensors since they have unique features that distinguish them from natural antibodies such as robustness, multiple binding sites, low cost, facile preparation and high stability under extreme operation conditions (higher pH and temperature values, etc.). On the other hand, the Quartz Crystal Microbalance (QCM) is an analytical tool based on the measurement of small mass changes on the sensor surface. QCM sensors are practical and convenient monitoring tools because of their specificity, sensitivity, high accuracy, stability and reproducibility. QCM devices are highly suitable for converting the recognition process achieved using MIP-based memories into a sensor signal. Therefore, the combination of a QCM and MIPs as synthetic receptors enhances the sensitivity through MIP process-based multiplexed binding sites using size, 3D-shape and chemical function having molecular memories of the prepared sensor system toward the target compound to be detected. This review aims to highlight and summarize the recent progress and studies in the field of (bio)sensor systems based on QCMs combined with molecular imprinting technology.

Imprinting high-gradient topographical structures onto optical surfaces using magnetorheological finishing: manufacturing corrective optical elements for high-power laser applications.

PubMed

Menapace, Joseph A; Ehrmann, Paul E; Bayramian, Andrew J; Bullington, Amber; Di Nicola, Jean-Michel G; Haefner, Constantin; Jarboe, Jeffrey; Marshall, Christopher; Schaffers, Kathleen I; Smith, Cal

2016-07-01

Corrective optical elements form an important part of high-precision optical systems. We have developed a method to manufacture high-gradient corrective optical elements for high-power laser systems using deterministic magnetorheological finishing (MRF) imprinting technology. Several process factors need to be considered for polishing ultraprecise topographical structures onto optical surfaces using MRF. They include proper selection of MRF removal function and wheel sizes, detailed MRF tool and interferometry alignment, and optimized MRF polishing schedules. Dependable interferometry also is a key factor in high-gradient component manufacture. A wavefront attenuating cell, which enables reliable measurement of gradients beyond what is attainable using conventional interferometry, is discussed. The results of MRF imprinting a 23 μm deep structure containing gradients over 1.6 μm / mm onto a fused-silica window are presented as an example of the technique's capabilities. This high-gradient element serves as a thermal correction plate in the high-repetition-rate advanced petawatt laser system currently being built at Lawrence Livermore National Laboratory.

Imprinting high-gradient topographical structures onto optical surfaces using magnetorheological finishing: Manufacturing corrective optical elements for high-power laser applications

DOE PAGES

Menapace, Joseph A.; Ehrmann, Paul E.; Bayramian, Andrew J.; ...

2016-03-15

Corrective optical elements form an important part of high-precision optical systems. We have developed a method to manufacture high-gradient corrective optical elements for high-power laser systems using deterministic magnetorheological finishing (MRF) imprinting technology. Several process factors need to be considered for polishing ultraprecise topographical structures onto optical surfaces using MRF. They include proper selection of MRF removal function and wheel sizes, detailed MRF tool and interferometry alignment, and optimized MRF polishing schedules. Dependable interferometry also is a key factor in high-gradient component manufacture. A wavefront attenuating cell, which enables reliable measurement of gradients beyond what is attainable using conventional interferometry,more » is discussed. The results of MRF imprinting a 23 μm deep structure containing gradients over 1.6 μm / mm onto a fused-silica window are presented as an example of the technique’s capabilities. As a result, this high-gradient element serves as a thermal correction plate in the high-repetition-rate advanced petawatt laser system currently being built at Lawrence Livermore National Laboratory.« less

Preparation and adsorption behavior of berberine hydrochloride imprinted polymers by using silica gel as sacrificed support material

NASA Astrophysics Data System (ADS)

Li, Hui; Li, Yuzhuo; Li, Zhiping; Peng, Xiyang; Li, Yanan; Li, Gui; Tan, Xianzhou; Chen, Gongxi

2012-03-01

Preparation of berberine hydrochloride (B-Cl) imprinted polymers (MIPs) based on surface imprinting technique with silica gel as sacrificial support material was performed successfully by using B-Cl as template, methacrylic acid (MAA) and ethylene glycol dimethacrylate (EGDMA) as functional monomer and cross-linker, respectively. The prepared polymers were characterized by Fourier transmission infrared spectrometry (FTIR) and scanning electron microscopy (SEM). Adsorption behavior of the MIPs for the template and its structural analogues was investigated. Sites distribution on the surface of MIPs was explored by using different isotherm adsorption models and thermodynamic parameters for the adsorption of B-Cl on the MIPs determined. Sample application and reusability for the MIPs was also evaluated. Results indicated the strong adsorption and high selectivity of the MIPs for B-Cl. Saturated adsorption capacity reached 27.2 μmol g-1 and the selectivity coefficient of the MIPs for B-Cl relative to jatrorrhizine hydrochloride (J-Cl) and palmatine palmatus hydrochloride (P-Cl) are 3.70 and 6.03, respectively. In addition, the MIPs were shown with good reusability and selectively retention ability in sample application.

Molecularly Imprinted Polymer Enables High-Efficiency Recognition and Trapping Lithium Polysulfides for Stable Lithium Sulfur Battery.

PubMed

Liu, Jie; Qian, Tao; Wang, Mengfan; Liu, Xuejun; Xu, Na; You, Yizhou; Yan, Chenglin

2017-08-09

Using molecularly imprinted polymer to recognize various target molecules emerges as a fascinating research field. Herein, we applied this strategy for the first time to efficiently recognize and trap long-chain polysulfides (Li 2 S x , x = 6-8) in lithium sulfur battery to minimize the polysulfide shuttling between anode and cathode, which enables us to achieve remarkable electrochemical performance including a high specific capacity of 1262 mAh g -1 at 0.2 C and superior capacity retention of over 82.5% after 400 cycles at 1 C. The outstanding performance is attributed to the significantly reduced concentration of long-chain polysulfides in electrolyte as evidenced by in situ UV/vis spectroscopy and Li 2 S nucleation tests, which were further confirmed by density functional theory calculations. The molecular imprinting is demonstrated as a promising approach to effectively prevent the free diffusion of long-chain polysulfides, providing a new avenue to efficiently recognize and trap lithium polysulfides for high-performance lithium sulfur battery with greatly suppressed shuttle effect.

Preparation and characterisation of core-shell CNTs@MIPs nanocomposites and selective removal of estrone from water samples.

PubMed

Gao, Ruixia; Su, Xiaoqian; He, Xiwen; Chen, Langxing; Zhang, Yukui

2011-01-15

This paper reports the preparation of carbon nanotubes (CNTs) functionalized with molecularly imprinted polymers (MIPs) for advanced removal of estrone. CNTs@Est-MIPs nanocomposites with a well-defined core-shell structure were obtained using a semi-covalent imprinting strategy, which employed a thermally reversible covalent bond at the surface of silica-coated CNTs for a large-scale production. The morphology and structure of the products were characterised by transmission electron microscopy and Fourier transform infrared spectroscopy. The adsorption properties were demonstrated by equilibrium rebinding experiments and Scatchard analysis. The results demonstrate that the imprinted nanocomposites possess favourable selectivity, high capacity and fast kinetics for template molecule uptake, yielding an adsorption capacity of 113.5 μmol/g. The synthetic process is quite simple, and the different batches of synthesized CNTs@Est-MIPs nanocomposites showed good reproducibility in template binding. The feasibility of removing estrogenic compounds from environmental water using the CNTs@Est-MIPs nanocomposites was demonstrated using water samples spiked with estrone. Copyright © 2010 Elsevier B.V. All rights reserved.

Molecularly imprinted solid-phase extraction for the determination of ten macrolide drugs residues in animal muscles by liquid chromatography-tandem mass spectrometry.

PubMed

Song, Xuqin; Zhou, Tong; Liu, Qingying; Zhang, Meiyu; Meng, Chenying; Li, Jiufeng; He, Limin

2016-10-01

A simple and sensitive method based on molecularly imprinted solid-phase extraction coupled with liquid chromatography-tandem mass spectrometry was developed for the determination of the residues of ten macrolide drugs in swine, cattle and chicken muscles samples. The molecularly imprinted polymers (MIPs) were synthesized using tylosin as a template and methacrylic acid as a functional monomer. Samples were extracted with sodium borate buffer solution and ethyl acetate, and purified by the MIP cartridge. The results showed that the cartridge exhibited good recognition performance for macrolides, and better purification effect than the traditional solid-phase extraction cartridges. Recoveries of analytes at three spiking levels 1, 5 and 20μgkg(-1) ranged from 60.7% to 100.3% with the relative standard deviations less than 14%. The limits of detection of the method were between 0.1 and 0.4μgkg(-1). The method is useful for the routine monitoring of the residues of macrolide drugs in animal muscles. Copyright © 2016 Elsevier Ltd. All rights reserved.

Preparation of Palladium(II) Ion-Imprinted Polymeric Nanospheres and Its Removal of Palladium(II) from Aqueous Solution

NASA Astrophysics Data System (ADS)

Tao, Hu-Chun; Gu, Yi-Han; Liu, Wei; Huang, Shuai-Bin; Cheng, Ling; Zhang, Li-Juan; Zhu, Li-Li; Wang, Yong

2017-11-01

Three kinds of functional monomers, 4-vinylpridine(4-VP), 2-(allylthio)nicotinic acid(ANA), and 2-Acetamidoacrylic acid(AAA), were used to synthetize palladium(II) ion-imprinted polymeric nanospheres (Pd(II) IIPs) via precipitation-polymerization method in order to study the effects of different functional monomers on the adsorption properties of ion-imprinted materials. The results of UV spectra in order to study the interaction between template ion PdCl4 2- and functional monomers showed that there were great differences in structure after the template reacted with three functional monomers, 4-VP and ANA caused a large structural change, while AAA basically did not change. Further results on the adsorption performance of Pd(II) IIPs on Pd(II) confirmed 4-VP was the most promising candidate for the synthesis of Pd(II) IIPs with an adsorption capacity of 5.042 mg/g as compared with ANA and AAA. The influence of operating parameters on Pd(II) IIP's performance on Pd(II) adsorption was investigated. There was an increase in the adsorption capacity of Pd(II) IIPs at higher pH, temperature, and initial concentration of Pd(II). The results of multi-metal competitive adsorption experiments showed that Pd(II) IIPs had selectivity for Pd(II). An adsorption equilibrium could be reached at 180 min. Kinetic analysis showed that the adsorption test data fitted best to the pseudo-second order kinetic model, and the theoretical equilibrium adsorption capacity was about 5.085 mg/g. The adsorption isotherms of Pd(II) by Pd(II) IIPs agreed well with the Freundlich equation, suggesting a favorable adsorption reaction under optimal conditions. These results showed that Pd(II) IIPs have potential application in the removal of Pd(II) from aqueous solutions and may provide some information for the selection of functional monomers in the preparation of Pd(II) IIPs.

Microgravity

NASA Image and Video Library

1997-01-12

This is a large 2 mm crystal of histone octamer, grown on STS-81. A very dynamic structure which functions in many aspects of gene regulation from control of gene activity to the more subtle mechanisms of genetic imprinting. Principle Investigator is Dan Carter of New Century Pharmaceuticals.

The effects of early post-hatching changes of imprinting object on the pattern of monocular/unihemispheric sleep of domestic chicks.

PubMed

Bobbo, Daniela; Vallortigara, Giorgio; Mascetti, Gian Gastone

2006-06-03

The pattern of monocular/unihemispheric sleep (Mo-Un sleep) was studied behaviourally in male and female chicks after early post-hatching changes of the imprinting object. Chicks were reared with an imprinting object on day 1 post-hatching which was removed or changed on day 2. On day 1, time spent in binocular sleep (both eyes closed) was similar in male and female chicks, though the number of episodes was lower in females than in males. There was no eye-closure bias in the pattern of Mo-Un sleep (one eye shut and the other open) in chicks of both sexes. On day 2, chicks subjected to the removal of imprinting object showed less time and number of episodes of binocular sleep than control chicks and chicks subjected to changes of imprinting object. There was no eye-closure bias in control chicks whilst a significant bias for more right Mo-Un sleep was recorded in chicks after removal and changes of imprinting object of both sexes. It is suggested that the removal or changes of imprinting object would cause a decrease of binocular sleep and trigger processes associated to secondary imprinting involving the left hemisphere. The bias for more right Mo-Un sleep (right eye-closure) could be the by-product of consolidation processes of secondary imprinting memories in the left hemisphere and/or of more left eye-opening as a result of periodical awakening of right hemisphere to control the environment after a stressful condition such as the removal or change of imprinting object.

Experimental evaluation of imprinting and the role innate preference plays in habitat selection in a coral reef fish.

PubMed

Dixson, Danielle L; Jones, Geoffrey P; Munday, Philip L; Planes, Serge; Pratchett, Morgan S; Thorrold, Simon R

2014-01-01

When facing decisions about where to live, juveniles have a strong tendency to choose habitats similar to where their parents successfully bred. Developing larval fishes can imprint on the chemical cues from their natal habitat. However, to demonstrate that imprinting is ecologically important, it must be shown that settlers respond and distinguish among different imprinted cues, and use imprinting for decisions in natural environments. In addition, the potential role innate preferences play compared to imprinted choices also needs to be examined. As environmental variability increases due to anthropogenic causes these two recognition mechanisms, innate and imprinting, could provide conflicting information. Here we used laboratory rearing and chemical choice experiments to test imprinting in larval anemonefish (Amphiprion percula). Individuals exposed to a variety of benthic habitat or novel olfactory cues as larvae either developed a preference for (spent >50% of their time in the cue) or increased their attraction to (increased preference but did not spend >50% of their time in the cue) the cue when re-exposed as settlers. Results indicate not only the capacity for imprinting but also the ability to adjust innate preferences after early exposure to a chemical cue. To test ecological relevance in the natural system, recruits were collected from anemones and related to their parents, using genetic parentage analysis, providing information on the natal anemone species and the species chosen at settlement. Results demonstrated that recruits did not preferentially return to their natal species, conflicting with laboratory results indicating the importance imprinting might have in habitat recognition.

Intraoperative analysis of sentinel lymph nodes by imprint cytology for cancer of the breast.

PubMed

Shiver, Stephen A; Creager, Andrew J; Geisinger, Kim; Perrier, Nancy D; Shen, Perry; Levine, Edward A

2002-11-01

The utilization of lymphatic mapping techniques for breast carcinoma has made intraoperative evaluation of sentinel lymph nodes (SLN) attractive, because axillary lymph node dissection can be performed during the initial surgery if the SLN is positive. The optimal technique for rapid SLN assessment has not been determined. Both frozen sectioning and imprint cytology are used for rapid intraoperative SLN evaluation. A retrospective review of the intraoperative imprint cytology results of 133 SLN mapping procedures from 132 breast carcinoma patients was performed. SLN were evaluated intraoperatively by bisecting the lymph node and making imprints of each cut surface. Imprints were stained with hematoxylin and eosin (H&E) and Diff-Quik. Permanent sections were evaluated with up to four H&E stained levels and cytokeratin immunohistochemistry. Imprint cytology results were compared with final histologic results. Sensitivity and specificity of imprint cytology were 56% and 100%, respectively, producing a 100% positive predictive value and 88% negative predictive value. Imprint cytology was significantly more sensitive for macrometastasis than micrometastasis 87% versus 22% (P = 0.00007). Of 13 total false negatives, 11 were found to be due to sampling error and 2 due to errors in intraoperative interpretation. Both intraoperative interpretation errors involved a diagnosis of lobular breast carcinoma. The sensitivity and specificity of imprint cytology are similar to that of frozen section evaluation. Imprint cytology is therefore a viable alternative to frozen sectioning when intraoperative evaluation is required. If SLN micrometastasis is used to determine the need for further lymphadenectomy, more sensitive intraoperative methods will be needed to avoid a second operation.

Self-oriented nanoparticles for site-selective immunoglobulin G recognition via epitope imprinting approach.

PubMed

Çorman, Mehmet Emin; Armutcu, Canan; Uzun, Lokman; Say, Rıdvan; Denizli, Adil

2014-11-01

Molecular imprinting is a polymerization technique that provides synthetic analogs for template molecules. Molecularly imprinted polymers (MIPs) have gained much attention due to their unique properties such as selectivity and specificity for target molecules. In this study, we focused on the development of polymeric materials with molecular recognition ability, so molecular imprinting was combined with miniemulsion polymerization to synthesize self-orienting nanoparticles through the use of an epitope imprinting approach. Thus, L-lysine imprinted nanoparticles (LMIP) were synthesized via miniemulsion polymerization technique. Immunoglobulin G (IgG) was then bound to the cavities that specifically formed for L-lysine molecules that are typically found at the C-terminus of the Fc region of antibody molecules. The resulting nanoparticles makes it possible to minimize the nonspecific interaction between monomer and template molecules. In addition, the orientation of the entire IgG molecule was controlled, and random imprinting of the IgG was prevented. The optimum conditions were determined for IgG recognition using the imprinted nanoparticles. The selectivity of the nanoparticles against IgG molecules was also evaluated using albumin and hemoglobin as competitor molecules. In order to show the self-orientation capability of imprinted nanoparticles, human serum albumin (HSA) adsorption onto both the plain nanoparticles and immobilized nanoparticles by anti-human serum albumin antibody (anti-HSA antibody) was also carried out. Due to anti-HSA antibody immobilization on the imprinted nanoparticles, the adsorption capability of nanoparticles against HSA molecules vigorously enhanced. It is proved that the oriented immobilization of antibodies was appropriately succeeded. Copyright © 2014 Elsevier B.V. All rights reserved.

Loss of insulin-like growth factor II imprinting is a hallmark associated with enhanced chemo/radiotherapy resistance in cancer stem cells.

PubMed

Zhao, Xin; Liu, Xiaoliang; Wang, Guanjun; Wen, Xue; Zhang, Xiaoying; Hoffman, Andrew R; Li, Wei; Hu, Ji-Fan; Cui, Jiuwei

2016-08-09

Insulin-like growth factor II (IGF2) is maternally imprinted in most tissues, but the epigenetic regulation of the gene in cancer stem cells (CSCs) has not been defined. To study the epigenetic mechanisms underlying self-renewal, we isolated CSCs and non-CSCs from colon cancer (HT29, HRT18, HCT116), hepatoma (Hep3B), breast cancer (MCF7) and prostate cancer (ASPC) cell lines. In HT29 and HRT18 cells that show loss of IGF2 imprinting (LOI), IGF2 was biallelically expressed in the isolated CSCs. Surprisingly, we also found loss of IGF2 imprinting in CSCs derived from cell lines HCT116 and ASPC that overall demonstrate maintenance of IGF2 imprinting. Using chromatin conformation capture (3C), we found that intrachromosomal looping between the IGF2 promoters and the imprinting control region (ICR) was abrogated in CSCs, in parallel with loss of IGF2 imprinting in these CSCs. Loss of imprinting led to increased IGF2 expression in CSCs, which have a higher rate of colony formation and greater resistance to chemotherapy and radiotherapy in vitro. These studies demonstrate that IGF2 LOI is a common feature in CSCs, even when the stem cells are derived from a cell line in which the general population of cells maintain IGF2 imprinting. This finding suggests that aberrant IGF2 imprinting may be an intrinsic epigenetic control mechanism that enhances stemness, self-renewal and chemo/radiotherapy resistance in cancer stem cells.

New generation ion-imprinted nanocarrier for removal of Cr(VI) from wastewater

NASA Astrophysics Data System (ADS)

Uygun, Murat; Feyzioğlu, Esra; Özçalışkan, Emir; Caka, Müşerref; Ergen, Aygen; Akgöl, Sinan; Denizli, Adil

2013-08-01

The purpose of this study was to prepare a novel ion-imprinted nanoparticle to remove Cr(VI) ions from waste water. For this, Cr(VI) ions were complexed with 2-methacryloylamido histidine (MAH) and then Cr(VI)-imprinted poly(HEMAH) nanoparticles were synthesized by surfactant-free emulsion polymerization technique. The templates, Cr(VI) ions, were removed from the nanoparticles using 0.1 M of HNO3 solution. The specific surface area of the Cr(VI)-imprinted poly(HEMAH) nanoparticles was found to be 1,397.85 m2/g, and the particle size was calculated as 155.3 nm. These Cr(VI)-imprinted nanoparticles were used for the adsorption/desorption of Cr(VI) ions from its aqueous solutions. The effects of initial Cr(VI) concentration and medium pH on the Cr(VI) adsorption capacity were also studied. The maximum adsorbed amount of Cr(VI) on the imprinted nanoparticles was found to be 3,830.58 mg/g nanoparticle in pH 4.0. In order to investigate the selectivity of the imprinted nanoparticle, adsorption studies were repeated using Cr(III) ions. The selectivity results demonstrated that Cr(VI)-imprinted poly(HEMAH) nanoparticles showed high affinity for the Cr(VI) ions than Cr(III). The Cr(VI)-imprinted nanoparticles were used several times without decreasing their Cr(VI) adsorption capacities.

Optimization of Shipboard Manning Levels Using Imprint Pro Forces Module

DTIC Science & Technology

2015-09-01

NPS-OR-15-008 NAVAL POSTGRADUATE SCHOOL MONTEREY, CALIFORNIA OPTIMIZATION OF SHIPBOARD MANNING LEVELS USING IMPRINT PRO...Optimization of Shipboard Manning Levels Using IMPRINT Pro Forces Module 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER...ABSTRACT The Improved Performance Research Integration Tool ( IMPRINT ) is a dynamic, stochastic, discrete-event modeling tool used to develop a model

Effect of equation of state on laser imprinting by comparing diamond and polystyrene foils

NASA Astrophysics Data System (ADS)

Kato, H.; Shigemori, K.; Nagatomo, H.; Nakai, M.; Sakaiya, T.; Ueda, T.; Terasaki, H.; Hironaka, Y.; Shimizu, K.; Azechi, H.

2018-03-01

We present herein a comprehensive study of how the equation of state affects laser imprinting by nonuniform laser irradiation of an inertial fusion target. It has been suggested that a stiffer and denser material would reduce laser imprinting based on the equation of motion with pressure perturbation. We examine the detailed temporal evolution of the imprint amplitude by using the two-dimensional radiation hydrodynamic simulation PINOCO-2D for diamond, which is a candidate stiff-ablator material for inertial fusion targets. The simulated laser imprinting amplitude is compared with experimental measurements of areal-density perturbations obtained by using face-on x-ray backlighting for diamond and polystyrene (PS) (the latter as a reference). The experimental results are well reproduced by the results of the PINOCO-2D simulation, which indicates that the imprinting amplitude due to nonuniform irradiation (average intensity, 4.0 × 1012 to 5.0 × 1013) differs by a factor of two to three between diamond and PS. The difference in laser imprinting is mainly related to the material density and compressibility. These parameters are key factors that determine the laser imprinting amplitude.

Transcriptome-wide investigation of genomic imprinting in chicken.

PubMed

Frésard, Laure; Leroux, Sophie; Servin, Bertrand; Gourichon, David; Dehais, Patrice; Cristobal, Magali San; Marsaud, Nathalie; Vignoles, Florence; Bed'hom, Bertrand; Coville, Jean-Luc; Hormozdiari, Farhad; Beaumont, Catherine; Zerjal, Tatiana; Vignal, Alain; Morisson, Mireille; Lagarrigue, Sandrine; Pitel, Frédérique

2014-04-01

Genomic imprinting is an epigenetic mechanism by which alleles of some specific genes are expressed in a parent-of-origin manner. It has been observed in mammals and marsupials, but not in birds. Until now, only a few genes orthologous to mammalian imprinted ones have been analyzed in chicken and did not demonstrate any evidence of imprinting in this species. However, several published observations such as imprinted-like QTL in poultry or reciprocal effects keep the question open. Our main objective was thus to screen the entire chicken genome for parental-allele-specific differential expression on whole embryonic transcriptomes, using high-throughput sequencing. To identify the parental origin of each observed haplotype, two chicken experimental populations were used, as inbred and as genetically distant as possible. Two families were produced from two reciprocal crosses. Transcripts from 20 embryos were sequenced using NGS technology, producing ∼200 Gb of sequences. This allowed the detection of 79 potentially imprinted SNPs, through an analysis method that we validated by detecting imprinting from mouse data already published. However, out of 23 candidates tested by pyrosequencing, none could be confirmed. These results come together, without a priori, with previous statements and phylogenetic considerations assessing the absence of genomic imprinting in chicken.

Thyroid hormone determines the start of the sensitive period of imprinting and primes later learning.

PubMed

Yamaguchi, Shinji; Aoki, Naoya; Kitajima, Takaaki; Iikubo, Eiji; Katagiri, Sachiko; Matsushima, Toshiya; Homma, Koichi J

2012-01-01

Filial imprinting in precocial birds is the process of forming a social attachment during a sensitive or critical period, restricted to the first few days after hatching. Imprinting is considered to be part of early learning to aid the survival of juveniles by securing maternal care. Here we show that the thyroid hormone 3,5,3'-triiodothyronine (T(3)) determines the start of the sensitive period. Imprinting training in chicks causes rapid inflow of T(3), converted from circulating plasma thyroxine by Dio2, type 2 iodothyronine deiodinase, in brain vascular endothelial cells. The T(3) thus initiates and extends the sensitive period to last more than 1 week via non-genomic mechanisms and primes subsequent learning. Even in non-imprinted chicks whose sensitive period has ended, exogenous T(3) enables imprinting. Our findings indicate that T(3) determines the start of the sensitive period for imprinting and has a critical role in later learning.

Thyroid hormone determines the start of the sensitive period of imprinting and primes later learning

PubMed Central

Yamaguchi, Shinji; Aoki, Naoya; Kitajima, Takaaki; Iikubo, Eiji; Katagiri, Sachiko; Matsushima, Toshiya; Homma, Koichi J.

2012-01-01

Filial imprinting in precocial birds is the process of forming a social attachment during a sensitive or critical period, restricted to the first few days after hatching. Imprinting is considered to be part of early learning to aid the survival of juveniles by securing maternal care. Here we show that the thyroid hormone 3,5,3′-triiodothyronine (T3) determines the start of the sensitive period. Imprinting training in chicks causes rapid inflow of T3, converted from circulating plasma thyroxine by Dio2, type 2 iodothyronine deiodinase, in brain vascular endothelial cells. The T3 thus initiates and extends the sensitive period to last more than 1 week via non-genomic mechanisms and primes subsequent learning. Even in non-imprinted chicks whose sensitive period has ended, exogenous T3 enables imprinting. Our findings indicate that T3 determines the start of the sensitive period for imprinting and has a critical role in later learning. PMID:23011135

Cell-Imprinted Substrates Modulate Differentiation, Redifferentiation, and Transdifferentiation.

PubMed

Bonakdar, Shahin; Mahmoudi, Morteza; Montazeri, Leila; Taghipoor, Mojtaba; Bertsch, Arnaud; Shokrgozar, Mohammad Ali; Sharifi, Shahriar; Majidi, Mohammad; Mashinchian, Omid; Hamrang Sekachaei, Mohammad; Zolfaghari, Pegah; Renaud, Philippe

2016-06-08

Differentiation of stem cells into mature cells through the use of physical approaches is of great interest. Here, we prepared smart nanoenvironments by cell-imprinted substrates based on chondrocytes, tenocytes, and semifibroblasts as templates and demonstrated their potential for differentiation, redifferentiation, and transdifferentiation. Analysis of shape and upregulation/downregulation of specific genes of stem cells, which were seeded on these cell-imprinted substrates, confirmed that imprinted substrates have the capability to induce specific shapes and molecular characteristics of the cell types that were used as templates for cell-imprinting. Interestingly, immunofluorescent staining of a specific protein in chondrocytes (i.e., collagen type II) confirmed that adipose-derived stem cells, semifibroblasts, and tenocytes can acquire the chondrocyte phenotype after a 14 day culture on chondrocyte-imprinted substrates. In summary, we propose that common polystyrene tissue culture plates can be replaced by this imprinting technique as an effective and promising way to regulate any cell phenotype in vitro with significant potential applications in regenerative medicine and cell-based therapies.

Preparation and application of hollow molecularly imprinted polymers with a super-high selectivity to the template protein.

PubMed

Chen, Yang; He, Xi-Wen; Mao, Jie; Li, Wen-You; Zhang, Yu-Kui

2013-10-01

Protein-imprinted polymers with hollow cores that have a super-high imprinting factor were prepared by etching the core of the surface-imprinted polymers that used silica particles as the support. Lysozyme as template was modified onto the surface of silica particles by a covalent method, and after polymerization and the removal of template molecules, channels through the polymer layer were formed, which allowed a single-protein molecule to come into the hollow core and attach to the binding sites inside the polymer layer. The adsorption experiments demonstrated that the hollow imprinted polymers had an extremely high binding capacity and selectivity, and thus a super-high imprinting factor was obtained. The as-prepared imprinted polymers were used to separate the template lysozyme from egg white successfully, indicating its high selectivity and potential application in the field of separation of protein from real samples. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Identification and resolution of artifacts in the interpretation of imprinted gene expression.

PubMed

Proudhon, Charlotte; Bourc'his, Déborah

2010-12-01

Genomic imprinting refers to genes that are epigenetically programmed in the germline to express exclusively or preferentially one allele in a parent-of-origin manner. Expression-based genome-wide screening for the identification of imprinted genes has failed to uncover a significant number of new imprinted genes, probably because of the high tissue- and developmental-stage specificity of imprinted gene expression. A very large number of technical and biological artifacts can also lead to the erroneous evidence of imprinted gene expression. In this article, we focus on three common sources of potential confounding effects: (i) random monoallelic expression in monoclonal cell populations, (ii) genetically determined monoallelic expression and (iii) contamination or infiltration of embryonic tissues with maternal material. This last situation specifically applies to genes that occur as maternally expressed in the placenta. Beside the use of reciprocal crosses that are instrumental to confirm the parental specificity of expression, we provide additional methods for the detection and elimination of these situations that can be misinterpreted as cases of imprinted expression.

Preparation and characterization of erythromycin molecularly imprinted polymers based on distillation-precipitation polymerization.

PubMed

Liu, Jiang; Li, Le; Tang, Hui; Zhao, Feilang; Ye, Bang-Ce; Li, Yingchun; Yao, Jun

2015-09-01

Erythromycin-imprinted polymers with excellent recognition properties were prepared by an innovative strategy called distillation-precipitation polymerization. The interaction between erythromycin and methacrylic acid was studied by ultraviolet absorption spectroscopy, and the as-prepared materials were characterized by Fourier-transform infrared spectroscopy and scanning electron microscopy. Moreover, their binding performances were evaluated in detail by static, kinetic and selective sorption tests. It was found that the molecularly imprinted polymers afforded good morphology, monodispersity, and high adsorption capacity when the fraction of the monomers was 7 vol% in the whole reaction system, and the adsorption data for imprinted polymers correlated well with the Langmuir model. The maximum capacity of the imprinted and the non-imprinted polymers for adsorbing erythromycin is 44.03 and 19.95 mg/g, respectively. The kinetic studies revealed that the adsorption process fitted a pseudo-second-order kinetic model. Furthermore, the imprinted polymers display higher affinity toward erythromycin, compared with its analogue roxithromycin. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Dopamine-imprinted monolithic column for capillary electrochromatography.

PubMed

Aşır, Süleyman; Sarı, Duygu; Derazshamshir, Ali; Yılmaz, Fatma; Şarkaya, Koray; Denizli, Adil

2017-11-01

A dopamine-imprinted monolithic column was prepared and used in capillary electrochromatography as stationary phase for the first time. Dopamine was selectively separated from aqueous solution containing the competitor molecule norepinephrine, which is similar in size and shape to the template molecule. Morphology of the dopamine-imprinted column was observed by scanning electron microscopy. The influence of the organic solvent content of mobile phase, applied pressure and pH of the mobile phase on the recognition of dopamine by the imprinted monolithic column has been evaluated, and the imprinting effect in the dopamine-imprinted monolithic polymer was verified. Developed dopamine-imprinted monolithic column resulted in excellent separation of dopamine from structurally related competitor molecule, norepinephrine. Separation was achieved in a short period of 10 min, with the electrophoretic mobility of 5.81 × 10 -5  m 2 V -1 s -1 at pH 5.0 and 500 mbar pressure. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Schedules of electric shock presentation in the behavioral control of imprinted ducklings.

PubMed

Barrett, J E

1972-09-01

The behavioral effects of various schedules of electric shock presentation were investigated during and after the imprinting of Peking ducklings to moving stimuli. The behavior of following a moving imprinted stimulus was differentially controlled by a multiple schedule of punishment and avoidance that respectively suppressed and maintained following behavior. Pole-pecking, reinforced by presentations of the imprinted stimulus, was suppressed by response-produced shock (punishment); various schedules of response-independent shock and delayed punishment had an overall minimal effect. The delivery of response-independent shock in the presence of one of two stimuli, both during and after imprinting, resulted in a marked reduction in choice of the stimulus paired with shock. The experiments provide no support for a differentiation of imprinting from learning on the basis of the behavioral effects of aversive stimuli. Instead, as is the case with other organisms, the schedule under which shock is delivered to imprinted ducklings appears to be an important determinant of the temporal patterning of subsequent behavior.

Comparative analysis of isodisomic and heterodisomic segments in cases with maternal uniparental disomy 14 suggests more than one imprinted region.

PubMed

Kotzot, D

2001-09-01

The results of molecular investigations of 21 cases with complete or segmental maternal uniparental disomy (UPD) 14 published in the literature were compared with respect to isodisomic and heterodisomic segments. The aim of the study was to find hints toward imprinted regions other than the recently defined imprinted segment 14q32. Three regions with no isodisomic molecular marker were found. The most distal of these regions located on 14q32.12 and 14q32.13 supports the hypothesis of genomic imprinting as the cause of the maternal UPD 14 phenotype by synteny to the maternally imprinted region on mouse distal chromosome 12 and correlation with the recently defined imprinting cluster on human chromosome 14q32. The other two heterodisomic areas located on 14q11.2-->14q12 and 14q21.1-->14q31.2 are hints toward one or more additional regions of genomic imprinting on human chromosome 14.

Lung dendritic cells imprint T cell lung homing and promote lung immunity through the chemokine receptor CCR4

PubMed Central

Strassner, James P.

2013-01-01

T cell trafficking into the lung is critical for lung immunity, but the mechanisms that mediate T cell lung homing are not well understood. Here, we show that lung dendritic cells (DCs) imprint T cell lung homing, as lung DC–activated T cells traffic more efficiently into the lung in response to inhaled antigen and at homeostasis compared with T cells activated by DCs from other tissues. Consequently, lung DC–imprinted T cells protect against influenza more effectively than do gut and skin DC–imprinted T cells. Lung DCs imprint the expression of CCR4 on T cells, and CCR4 contributes to T cell lung imprinting. Lung DC–activated, CCR4-deficient T cells fail to traffic into the lung as efficiently and to protect against influenza as effectively as lung DC–activated, CCR4-sufficient T cells. Thus, lung DCs imprint T cell lung homing and promote lung immunity in part through CCR4. PMID:23960189

Nicotine molecularly imprinted polymer: synergy of coordination and hydrogen bonding.

PubMed

Huynh, Tan-Phat; B K C, Chandra; Sosnowska, Marta; Sobczak, Janusz W; Nesterov, Vladimir N; D'Souza, Francis; Kutner, Wlodzimierz

2015-02-15

Two new bis(2,2'-bithienyl)methane derivatives, one with the zinc phthalocyanine substituent (ZnPc-S16) and the other with the 2-hydroxyethyl substituent (EtOH-S4), were synthesized to serve as functional monomers for biomimetic recognition of nicotine (Nic) by molecular imprinting. Formation of a pre-polymerization complex of the Nic template with ZnPc-S16 and EtOH-S4 was confirmed by both the high negative Gibbs free energy gain, ΔG = -115.95 kJ/mol, calculated using the density functional theory at the B3LYP/3-21G* level, and the high stability constant, Ks = 4.67 × 10(5) M(-1), determined by UV-vis titration in chloroform. A solution of this complex was used to deposit a Nic-templated molecularly imprinted polymer (MIP-Nic) film on an Au electrode of a quartz crystal resonator of EQCM by potentiodynamic electropolymerization. The imprinting factor was as high as ~9.9. Complexation of the Nic molecules by the MIP cavities was monitored with X-ray photoelectron spectroscopy (XPS), as manifested by a negative shift of the binding energy of the Zn 2p3/2 electron of ZnPc-S16 after Nic templating. For sensing applications, simultaneous chronoamperometry (CA) and piezoelectric microgravimetry (PM) measurements were performed under flow-injection analysis conditions. The limit of detection of the CA and PM chemosensing was as low as 40 and 12 µM, respectively. Among them, the CA chemosensing was more selective to the cotinine and myosmine interferences due to the 1.10 V vs. Ag/AgCl discriminating potential of nicotine electro-oxidation applied. Differences in selectivity to the analyte and interferences were interpreted by modeling complexation of Nic and, separately, each of the interferences with a "frozen" MIP-Nic molecular cavity. Copyright © 2014 Elsevier B.V. All rights reserved.

Molecularly Imprinted Sol-Gel-Based QCM Sensor Arrays for the Detection and Recognition of Volatile Aldehydes.

PubMed

Liu, Chuanjun; Wyszynski, Bartosz; Yatabe, Rui; Hayashi, Kenshi; Toko, Kiyoshi

2017-02-16

The detection and recognition of metabolically derived aldehydes, which have been identified as important products of oxidative stress and biomarkers of cancers; are considered as an effective approach for early cancer detection as well as health status monitoring. Quartz crystal microbalance (QCM) sensor arrays based on molecularly imprinted sol-gel (MISG) materials were developed in this work for highly sensitive detection and highly selective recognition of typical aldehyde vapors including hexanal (HAL); nonanal (NAL) and bezaldehyde (BAL). The MISGs were prepared by a sol-gel procedure using two matrix precursors: tetraethyl orthosilicate (TEOS) and tetrabutoxytitanium (TBOT). Aminopropyltriethoxysilane (APT); diethylaminopropyltrimethoxysilane (EAP) and trimethoxy-phenylsilane (TMP) were added as functional monomers to adjust the imprinting effect of the matrix. Hexanoic acid (HA); nonanoic acid (NA) and benzoic acid (BA) were used as psuedotemplates in view of their analogous structure to the target molecules as well as the strong hydrogen-bonding interaction with the matrix. Totally 13 types of MISGs with different components were prepared and coated on QCM electrodes by spin coating. Their sensing characters towards the three aldehyde vapors with different concentrations were investigated qualitatively. The results demonstrated that the response of individual sensors to each target strongly depended on the matrix precursors; functional monomers and template molecules. An optimization of the 13 MISG materials was carried out based on statistical analysis such as principle component analysis (PCA); multivariate analysis of covariance (MANCOVA) and hierarchical cluster analysis (HCA). The optimized sensor array consisting of five channels showed a high discrimination ability on the aldehyde vapors; which was confirmed by quantitative comparison with a randomly selected array. It was suggested that both the molecularly imprinting (MIP) effect and the matrix effect contributed to the sensitivity and selectivity of the optimized sensor array. The developed MISGs were expected to be promising materials for the detection and recognition of volatile aldehydes contained in exhaled breath or human body odor.

Molecularly Imprinted Sol-Gel-Based QCM Sensor Arrays for the Detection and Recognition of Volatile Aldehydes

PubMed Central

Liu, Chuanjun; Wyszynski, Bartosz; Yatabe, Rui; Hayashi, Kenshi; Toko, Kiyoshi

2017-01-01

The detection and recognition of metabolically derived aldehydes, which have been identified as important products of oxidative stress and biomarkers of cancers; are considered as an effective approach for early cancer detection as well as health status monitoring. Quartz crystal microbalance (QCM) sensor arrays based on molecularly imprinted sol-gel (MISG) materials were developed in this work for highly sensitive detection and highly selective recognition of typical aldehyde vapors including hexanal (HAL); nonanal (NAL) and bezaldehyde (BAL). The MISGs were prepared by a sol-gel procedure using two matrix precursors: tetraethyl orthosilicate (TEOS) and tetrabutoxytitanium (TBOT). Aminopropyltriethoxysilane (APT); diethylaminopropyltrimethoxysilane (EAP) and trimethoxy-phenylsilane (TMP) were added as functional monomers to adjust the imprinting effect of the matrix. Hexanoic acid (HA); nonanoic acid (NA) and benzoic acid (BA) were used as psuedotemplates in view of their analogous structure to the target molecules as well as the strong hydrogen-bonding interaction with the matrix. Totally 13 types of MISGs with different components were prepared and coated on QCM electrodes by spin coating. Their sensing characters towards the three aldehyde vapors with different concentrations were investigated qualitatively. The results demonstrated that the response of individual sensors to each target strongly depended on the matrix precursors; functional monomers and template molecules. An optimization of the 13 MISG materials was carried out based on statistical analysis such as principle component analysis (PCA); multivariate analysis of covariance (MANCOVA) and hierarchical cluster analysis (HCA). The optimized sensor array consisting of five channels showed a high discrimination ability on the aldehyde vapors; which was confirmed by quantitative comparison with a randomly selected array. It was suggested that both the molecularly imprinting (MIP) effect and the matrix effect contributed to the sensitivity and selectivity of the optimized sensor array. The developed MISGs were expected to be promising materials for the detection and recognition of volatile aldehydes contained in exhaled breath or human body odor. PMID:28212347

Adsorption Behavior of Selective Recognition Functionalized Biochar to Cd(II) in Wastewater

PubMed Central

Zhang, Shiqiu; Yang, Xue; Liu, Le; Ju, Meiting; Zheng, Kui

2018-01-01

Biochar is an excellent absorbent for most heavy metal ions and organic pollutants with high specific surface area, strong aperture structure, high stability, higher cation exchange capacity and rich surface functional groups. To improve the selective adsorption capacity of biochar to designated heavy metal ions, biochar prepared by agricultural waste is modified via Ionic-Imprinted Technique. Fourier transform infrared (FT-IR) spectra analysis and X-ray photoelectron spectroscopy (XPS) analysis of imprinted biochar (IB) indicate that 3-Mercaptopropyltrimethoxysilane is grafted on biochar surface through Si–O–Si bonds. The results of adsorption experiments indicate that the suitable pH range is about 3.0–8.0, the dosage is 2.0 g·L−1, and the adsorption equilibrium is reached within 960 min. In addition, the data match pseudo-second-order kinetic model and Langmuir model well. The computation results of adsorption thermodynamics and stoichiometric displacement theory of adsorption (SDT-A) prove that the adsorption process is spontaneous and endothermic. Finally, IB possesses a higher selectivity adsorption to Cd(II) and a better reuse capacity. The functionalized biochar could solidify designated ions stably. PMID:29443954

Towards Phosphate Detection in Hydroponics Using Molecularly Imprinted Polymer Sensors.

PubMed

Storer, Christopher S; Coldrick, Zachary; Tate, Daniel J; Donoghue, Jack Marsden; Grieve, Bruce

2018-02-10

An interdigitated electrode sensor was designed and microfabricated for measuring the changes in the capacitance of three phosphate selective molecularly imprinted polymer (MIP) formulations, in order to provide hydroponics users with a portable nutrient sensing tool. The MIPs investigated were synthesised using different combinations of the functional monomers methacrylic acid (MAA) and N -allylthiourea, against the template molecules diphenyl phosphate, triethyl phosphate, and trimethyl phosphate. A cross-interference study between phosphate, nitrate, and sulfate was carried out for the MIP materials using an inductance, capacitance, and resistance (LCR) meter. Capacitance measurements were taken by applying an alternating current (AC) with a potential difference of 1 V root mean square (RMS) at a frequency of 1 kHz. The cross-interference study demonstrated a strong binding preference to phosphate over the other nutrient salts tested for each formulation. The size of template molecule and length of the functional monomer side groups also determined that a short chain functional monomer in combination with a template containing large R-groups produced the optimal binding site conditions when synthesising a phosphate selective MIP.

Towards Phosphate Detection in Hydroponics Using Molecularly Imprinted Polymer Sensors

PubMed Central

Storer, Christopher S.; Coldrick, Zachary; Donoghue, Jack Marsden

2018-01-01

An interdigitated electrode sensor was designed and microfabricated for measuring the changes in the capacitance of three phosphate selective molecularly imprinted polymer (MIP) formulations, in order to provide hydroponics users with a portable nutrient sensing tool. The MIPs investigated were synthesised using different combinations of the functional monomers methacrylic acid (MAA) and N-allylthiourea, against the template molecules diphenyl phosphate, triethyl phosphate, and trimethyl phosphate. A cross-interference study between phosphate, nitrate, and sulfate was carried out for the MIP materials using an inductance, capacitance, and resistance (LCR) meter. Capacitance measurements were taken by applying an alternating current (AC) with a potential difference of 1 V root mean square (RMS) at a frequency of 1 kHz. The cross-interference study demonstrated a strong binding preference to phosphate over the other nutrient salts tested for each formulation. The size of template molecule and length of the functional monomer side groups also determined that a short chain functional monomer in combination with a template containing large R-groups produced the optimal binding site conditions when synthesising a phosphate selective MIP. PMID:29439386

Fabrication of an electrochemical sensor based on computationally designed molecularly imprinted polymer for the determination of mesalamine in real samples.

PubMed

Torkashvand, M; Gholivand, M B; Taherkhani, F

2015-10-01

A novel electrochemical sensor based on mesalamine molecularly imprinted polymer (MIP) film on a glassy carbon electrode was fabricated. Density functional theory (DFT) in gas and solution phases was developed to study the intermolecular interactions in the pre-polymerization mixture and to find the suitable functional monomers in MIP preparation. On the basis of computational results, o-phenylenediamine (OP), gallic acid (GA) and p-aminobenzoic acid (ABA) were selected as functional monomers. The MIP film was cast on glassy carbon electrode by electropolymerization of solution containing ternary monomers and then followed by Ag dendrites (AgDs) with nanobranch deposition. The surface feature of the modified electrode (AgDs/MIP/GCE) was characterized by scanning electron microscopy (SEM) and electrochemical impedance spectroscopy (EIS). Under the optimal experimental conditions, the peak current was proportional to the concentration of mesalamine ranging from 0.05 to 100 μM, with the detection limit of 0.015 μM. The proposed sensor was applied successfully for mesalamine determination in real samples. Copyright © 2015 Elsevier B.V. All rights reserved.

Imprinting, latchment and displacement: a mini review of early instinctual behaviour in newborn infants influencing breastfeeding success.

PubMed

Mobbs, Elsie J; Mobbs, George A; Mobbs, Anthony E D

2016-01-01

Instinctive behaviours have evolved favouring the mother-infant dyad based on fundamental processes of neurological development, including oral tactile imprinting and latchment. Latchment is the first stage of emotional development based on the successful achievement of biological imprinting. The mechanisms underpinning imprinting are identified and the evolutionary benefits discussed. It is proposed that the oral tactile imprint to the breast is a keystone for optimal latchment and breastfeeding, promoting evolutionary success. ©2015 The Authors. Acta Paediatrica published by John Wiley & Sons Ltd on behalf of Foundation Acta Paediatrica.

Abnormal sudomotor function in the hypomelanotic macules of tuberous sclerosis complex.

PubMed

Chudnow, R S; Wolfe, G I; Sparagana, S P; Delgado, M R; Batchelor, L; Roach, E S

2000-08-01

To investigate the integrity of sympathetic innervation in the hypomelanotic macules of tuberous sclerosis complex, we studied sudomotor function in nine patients with tuberous sclerosis complex. Postganglionic sudomotor function was assessed using the Silastic imprint test in nine patients with tuberous sclerosis complex who have at least one hypomelanotic macule greater than 2 cm in diameter. Sweating was induced by iontophoresis with 0.5% pilocarpine nitrate and sweat droplets were counted under a microscope using a 1 x 1 cm grid. Silastic imprint testing of an analogous skin area contralateral to the hypomelanotic macule was measured as a control. Sweat volume quantitation using sweat collectors was performed in five of the subjects. The sweat volume collected from the hypomelanotic macule was reduced compared to the control skin in four of the five subjects. Sweat droplet counts from the hypomelanotic macule were significantly reduced in only one of nine subjects. These data suggest that, although there is no difference in the number of functioning sweat glands in most hypomelanotic macules, the sweat glands produce less sweat (ie, decreased sweat volume) than in normal skin. We hypothesize that focal abnormalities of sympathetic innervation might be responsible for the hypomelanotic macules of tuberous sclerosis complex.

Disturbed Placental Imprinting in Preeclampsia Leads to Altered Expression of DLX5, a Human-Specific Early Trophoblast Marker

PubMed Central

Zadora, Julianna; Singh, Manvendra; Herse, Florian; Przybyl, Lukasz; Haase, Nadine; Golic, Michaela; Yung, Hong Wa; Huppertz, Berthold; Cartwright, Judith E.; Whitley, Guy; Johnsen, Guro M.; Levi, Giovanni; Isbruch, Annette; Schulz, Herbert; Luft, Friedrich C.; Müller, Dominik N.; Staff, Anne Cathrine

2017-01-01

Background: Preeclampsia is a complex and common human-specific pregnancy syndrome associated with placental pathology. The human specificity provides both intellectual and methodological challenges, lacking a robust model system. Given the role of imprinted genes in human placentation and the vulnerability of imprinted genes to loss of imprinting changes, there has been extensive speculation, but no robust evidence, that imprinted genes are involved in preeclampsia. Our study aims to investigate whether disturbed imprinting contributes to preeclampsia. Methods: We first aimed to confirm that preeclampsia is a disease of the placenta by generating and analyzing genome-wide molecular data on well-characterized patient material. We performed high-throughput transcriptome analyses of multiple placenta samples from healthy controls and patients with preeclampsia. Next, we identified differentially expressed genes in preeclamptic placentas and intersected them with the list of human imprinted genes. We used bioinformatics/statistical analyses to confirm association between imprinting and preeclampsia and to predict biological processes affected in preeclampsia. Validation included epigenetic and cellular assays. In terms of human specificity, we established an in vitro invasion-differentiation trophoblast model. Our comparative phylogenetic analysis involved single-cell transcriptome data of human, macaque, and mouse preimplantation embryogenesis. Results: We found disturbed placental imprinting in preeclampsia and revealed potential candidates, including GATA3 and DLX5, with poorly explored imprinted status and no prior association with preeclampsia. As a result of loss of imprinting, DLX5 was upregulated in 69% of preeclamptic placentas. Levels of DLX5 correlated with classic preeclampsia markers. DLX5 is expressed in human but not in murine trophoblast. The DLX5high phenotype resulted in reduced proliferation, increased metabolism, and endoplasmic reticulum stress-response activation in trophoblasts in vitro. The transcriptional profile of such cells mimics the transcriptome of preeclamptic placentas. Pan-mammalian comparative analysis identified DLX5 as part of the human-specific regulatory network of trophoblast differentiation. Conclusions: Our analysis provides evidence of a true association among disturbed imprinting, gene expression, and preeclampsia. As a result of disturbed imprinting, the upregulated DLX5 affects trophoblast proliferation. Our in vitro model might fill a vital niche in preeclampsia research. Human-specific regulatory circuitry of DLX5 might help explain certain aspects of preeclampsia. PMID:28904069

Disturbed Placental Imprinting in Preeclampsia Leads to Altered Expression of DLX5, a Human-Specific Early Trophoblast Marker.

PubMed

Zadora, Julianna; Singh, Manvendra; Herse, Florian; Przybyl, Lukasz; Haase, Nadine; Golic, Michaela; Yung, Hong Wa; Huppertz, Berthold; Cartwright, Judith E; Whitley, Guy; Johnsen, Guro M; Levi, Giovanni; Isbruch, Annette; Schulz, Herbert; Luft, Friedrich C; Müller, Dominik N; Staff, Anne Cathrine; Hurst, Laurence D; Dechend, Ralf; Izsvák, Zsuzsanna

2017-11-07

Preeclampsia is a complex and common human-specific pregnancy syndrome associated with placental pathology. The human specificity provides both intellectual and methodological challenges, lacking a robust model system. Given the role of imprinted genes in human placentation and the vulnerability of imprinted genes to loss of imprinting changes, there has been extensive speculation, but no robust evidence, that imprinted genes are involved in preeclampsia. Our study aims to investigate whether disturbed imprinting contributes to preeclampsia. We first aimed to confirm that preeclampsia is a disease of the placenta by generating and analyzing genome-wide molecular data on well-characterized patient material. We performed high-throughput transcriptome analyses of multiple placenta samples from healthy controls and patients with preeclampsia. Next, we identified differentially expressed genes in preeclamptic placentas and intersected them with the list of human imprinted genes. We used bioinformatics/statistical analyses to confirm association between imprinting and preeclampsia and to predict biological processes affected in preeclampsia. Validation included epigenetic and cellular assays. In terms of human specificity, we established an in vitro invasion-differentiation trophoblast model. Our comparative phylogenetic analysis involved single-cell transcriptome data of human, macaque, and mouse preimplantation embryogenesis. We found disturbed placental imprinting in preeclampsia and revealed potential candidates, including GATA3 and DLX5 , with poorly explored imprinted status and no prior association with preeclampsia. As a result of loss of imprinting, DLX5 was upregulated in 69% of preeclamptic placentas. Levels of DLX5 correlated with classic preeclampsia markers. DLX5 is expressed in human but not in murine trophoblast. The DLX5 high phenotype resulted in reduced proliferation, increased metabolism, and endoplasmic reticulum stress-response activation in trophoblasts in vitro. The transcriptional profile of such cells mimics the transcriptome of preeclamptic placentas. Pan-mammalian comparative analysis identified DLX5 as part of the human-specific regulatory network of trophoblast differentiation. Our analysis provides evidence of a true association among disturbed imprinting, gene expression, and preeclampsia. As a result of disturbed imprinting, the upregulated DLX5 affects trophoblast proliferation. Our in vitro model might fill a vital niche in preeclampsia research. Human-specific regulatory circuitry of DLX5 might help explain certain aspects of preeclampsia. © 2017 The Authors.

Haloperidol impairs auditory filial imprinting and modulates monoaminergic neurotransmission in an imprinting-relevant forebrain area of the domestic chick.

PubMed

Gruss, M; Bock, J; Braun, K

2003-11-01

In vivo microdialysis and behavioural studies in the domestic chick have shown that glutamatergic as well as monoaminergic neurotransmission in the medio-rostral neostriatum/hyperstriatum ventrale (MNH) is altered after auditory filial imprinting. In the present study, using pharmaco-behavioural and in vivo microdialysis approaches, the role of dopaminergic neurotransmission in this juvenile learning event was further evaluated. The results revealed that: (i) the systemic application of the potent dopamine receptor antagonist haloperidol (7.5 mg/kg) strongly impairs auditory filial imprinting; (ii) systemic haloperidol induces a tetrodotoxin-sensitive increase of extracellular levels of the dopamine metabolite, homovanillic acid, in the MNH, whereas the levels of glutamate, taurine and the serotonin metabolite, 5-hydroxyindole-3-acetic acid, remain unchanged; (iii) haloperidol (0.01, 0.1, 1 mm) infused locally into the MNH increases glutamate, taurine and 5- hydroxyindole-3-acetic acid levels in a dose-dependent manner, whereas homovanillic acid levels remain unchanged; (iv) systemic haloperidol infusion reinforces the N-methyl-d-aspartate receptor-mediated inhibitory modulation of the dopaminergic neurotransmission within the MNH. These results indicate that the modulation of dopaminergic function and its interaction with other neurotransmitter systems in a higher associative forebrain region of the juvenile avian brain displays similar neurochemical characteristics as the adult mammalian prefrontal cortex. Furthermore, we were able to show that the pharmacological manipulation of monoaminergic regulatory mechanisms interferes with learning and memory formation, events which in a similar fashion might occur in young or adult mammals.

Design, fabrication and evaluation of intelligent sulfone-selective polybenzimidazole nanofibers.

PubMed

Ogunlaja, Adeniyi S; du Sautoy, Carol; Torto, Nelson; Tshentu, Zenixole R

2014-08-01

Molecularly imprinted polybenzimidazole nanofibers fabricated for the adsorption of oxidized organosulfur compounds are presented. The imprinted polymers exhibited better selectivity for their target model sulfone-containing compounds with adsorption capacities of 28.5±0.4mg g(-1), 29.8±2.2mg g(-1) and 20.1±1.4mg g(-1) observed for benzothiophene sulfone (BTO2), dibenzothiophene sulfone (DBTO2) and 4,6-dimethyldibenzothiophene sulfone (4,6-DMDBTO2) respectively. Molecular modeling based upon the density functional theory (DFT) indicated that hydrogen bond interactions may take place between sulfone oxygen groups with NH groups of the PBI. Further DFT also confirmed the feasibility of π-π interactions between the benzimidazole rings and the aromatic sulfone compounds. The adsorption mode followed the Freundlich (multi-layered) adsorption isotherm which indicated possible sulfone-sulfone interactions. A home-made pressurized hot water extraction (PHWE) system was employed for the extraction/desorption of sulfone compounds within imprinted nanofibers at 1mL min(-1), 150°C and 30 bar. PHWE used a green solvent (water) and achieved better extraction yields compared to the Soxhlet extraction process. The application of molecularly imprinted polybenzimidazole (PBI) nanofibers displayed excellent sulfur removal, with sulfur in fuel after adsorption falling below the determined limit of detection (LOD), which is 2.4mg L(-1)S, and with a sulfur adsorption capacity of 5.3±0.4mg g(-1) observed for application in the fuel matrix. Copyright © 2014 Elsevier B.V. All rights reserved.

Preparation, characterization and adsorption study of o-cresol molecularly imprinted grafted silica gel sorbent synthesized by sol-gel polymerization

NASA Astrophysics Data System (ADS)

Zinalibdin, Mohamad Raizul; Jaafar, Jafariah; Majid, Zaiton Abdul; Sanagi, Mohd Marsin

2017-11-01

In this study, a new composite core-shell of o-cresol molecularly imprinted polymer grafted silica gel (MIP@SiO2) was prepared via sol-gel polymerization. It was synthesized using o-cresol as the template molecule, 3-propyl(metacrylate)trimethoxysilane (3-PMTMOS) as the functional monomer, tetraethoxysilane (TEOS) as the cross-linker and ethanol as the porogenic solvent in the surface of silica gel. The non-imprinted polymer-grafted silica gel (NIP@SiO2) was prepared with the same technique but without template molecule. This analyte was selected as a template due to the fact that it is one of toluene metabolites. The characterization of MIP@SiO2 and NIP@SiO2 were observed by N2 adsorption analysis and Field emission scanning electron microscopy-energy dispersive x-ray (FESEM-EDX). The MIP@SiO2 and NIP@SiO2 were employed as an adsorbent for the extraction of o-cresol, a metabolite in urine sample for the monitoring of occupational toluene exposure in workers. Based on the results of the adsorption study, the MIP prepared using 0.5 mmol 3-(propylmethacrylate)trimethoxysilane), 10 mL of ethanol, 4 mmol TEOS,0.05 mmol o-cresol, 0.1g silica gel and 1mL of 0.01 mol/L acetic acid was found the adsorption capacity (0.9920 mg g-1) and imprint factor (5.21).

Qualification of a precise and easy-to-handle sweat casting imprint method for the prediction and quantification of anti-perspirant efficacy.

PubMed

Keyhani, R; Scheede, S; Thielecke, I; Wenck, H; Schmucker, R; Schreiner, V; Ennen, J; Herpens, A

2009-06-01

A time- and cost-effective sweat casting method using the forearm as test site to assess the efficacy of several anti-perspirant formulations with a low number of test subjects has been evaluated and qualified. The imprint sweat casting method is based on a 2-component silcone-imprint technique to measure the efficacy of more than eight products in parallel with the same test subject. In studies using aluminum chlorohydrate (ACH) formulations as test anti-perspirants, a clear-cut correlation could be demonstrated between sweat gland activities measured by the imprint method and gravimetric measurement of sweat gland activities. Concentration-dependent inhibition of sweat gland activity could be observed with the imprint technique up to an ACH concentration of 15%, and all formulations containing 2% ACH or above resulted in statistically significant reduction of sweat gland activity (P < 0.001) when compared with untreated control areas. Furthermore, the SDs of individual studies using the imprint technique were in a range of +/-20% of sweat gland activity, which can be regarded rather low for in vivo measurements of a complex process like sweat secretion. A group-wise comparison between the measurements of anti-perspirant activity as determined by the imprint protocol and the Food and Drug Administration (FDA) Guideline compliant gravimetric hot-room protocol revealed that the test results for anti-perspirant activity obtained with the imprint protocol are similar to those obtained with the hot-room protocol. Moreover, the data generated with the imprint protocol have a high predictive value for the outcome of a later guideline-compliant hot-room test. As the imprint casting method tends to be a little more sensitive for formulations with low anti-perspirant activity, and seems to be associated with less interassay variability than the standard gravimetric hot-room test, the imprint casting method may select products which later fail to pass the standard gravimetric hot-room test. Meanwhile the imprint sweat casting has proven to be a robust method useful to support efficacy-oriented product development. Therefore, in later stages of utilization it might even evolve into an efficient claim substantiation tool.

Does imprint cytology improve the accuracy of transrectal prostate needle biopsy?

PubMed

Sayar, Hamide; Bulut, Burak Besir; Bahar, Abdulkadir Yasir; Bahar, Mustafa Remzi; Seringec, Nurten; Resim, Sefa; Çıralık, Harun

2015-02-01

To evaluate the accuracy of imprint cytology of core needle biopsy specimens in the diagnosis of prostate cancer. Between December 24, 2011 and May 9, 2013, patients with an abnormal DRE and/or serum PSA level of >2.5 ng/mL underwent transrectal prostate needle biopsy. Samples with positive imprint cytology but negative initial histologic exam underwent repeat sectioning and histological examination. 1,262 transrectal prostate needle biopsy specimens were evaluated from 100 patients. Malignant imprint cytology was found in 236 specimens (18.7%), 197 (15.6%) of which were confirmed by histologic examination, giving an initial 3.1% (n = 39) rate of discrepant results by imprint cytology. Upon repeat sectioning and histologic examination of these 39 biopsy samples, 14 (1.1% of the original specimens) were then diagnosed as malignant, 3 (0.2%) as atypical small acinar proliferation (ASAP), and 5 (0.4%) as high-grade prostatic intraepithelial neoplasia (HGPIN). Overall, 964 (76.4%) specimens were negative for malignancy by imprint cytology. Seven (0.6%) specimens were benign by cytology but malignant cells were found on histological evaluation. On imprint cytology examination, nonmalignant but abnormal findings were seen in 62 specimens (4.9%). These were all due to benign processes. After reexamination, the accuracy, sensitivity, specificity, positive predictive value, negative predictive value, false-positive rate, false-negative rate of imprint preparations were 98.1, 96.9, 98.4, 92.8, 99.3, 1.6, 3.1%, respectively. Imprint cytology is valuable tool for evaluating TRUS-guided core needle biopsy specimens from the prostate. Use of imprint cytology in combination with histopathology increases diagnostic accuracy when compared with histopathologic assessment alone. © 2014 Wiley Periodicals, Inc.

DDC and COBL, flanking the imprinted GRB10 gene on 7p12, are biallelically expressed.

PubMed

Hitchins, Megan P; Bentley, Louise; Monk, David; Beechey, Colin; Peters, Jo; Kelsey, Gavin; Ishino, Fumitoshi; Preece, Michael A; Stanier, Philip; Moore, Gudrun E

2002-12-01

Maternal duplication of human 7p11.2-p13 has been associated with Silver-Russell syndrome (SRS) in two familial cases. GRB10 is the only imprinted gene identified within this region to date. GRB10 demonstrates an intricate tissue- and isoform-specific imprinting profile in humans, with paternal expression in fetal brain and maternal expression of one isoform in skeletal muscle. The mouse homolog is maternally transcribed. The GRB10 protein is a potent growth inhibitor and represents a candidate for SRS, which is characterized by pre- and postnatal growth retardation and a spectrum of additional dysmorphic features. Since imprinted genes tend to be grouped in clusters, we investigated the imprinting status of the dopa-decarboxylase gene (DDC) and the Cordon-bleu gene (COBL) which flank GRB10 within the 7p11.2-p13 SRS duplicated region. Although both genes were found to replicate asynchronously, suggestive of imprinting, SNP expression analyses showed that neither gene was imprinted in multiple human fetal tissues. The mouse homologues, Ddc and Cobl, which map to the homologous imprinted region on proximal Chr 11, were also biallelically expressed in mice with uniparental maternal or paternal inheritance of this region. With the intent of using mouse Grb10 as an imprinted control, biallelic expression was consistently observed in fetal, postnatal, and adult brain of these mice, in contrast to the maternal-specific transcription previously demonstrated in brain in inter-specific F1 progeny. This may be a further example of over-expression of maternally derived transcripts in inter-specific mouse crosses. GRB10 remains the only imprinted gene identified within 7p11.2-p13.

Imprint cytology on microcalcifications excised by vacuum-assisted breast biopsy: a rapid preliminary diagnosis.

PubMed

Fotou, Maria; Oikonomou, Vassiliki; Zagouri, Flora; Sergentanis, Theodoros N; Nonni, Afroditi; Athanassiadou, Pauline; Drouveli, Theodora; Atsouris, Efstratios; Kotzia, Evagelia; Zografos, George C

2007-04-03

To evaluate imprint cytology in the context of specimens with microcalcifications derived from Vacuum-Assisted Breast Biopsy (VABB). A total of 93 women with microcalcifications BI-RADS 3 and 4 underwent VABB and imprint samples were examined. VABB was performed on Fischer's table using 11-gauge Mammotome vacuum probes. A mammogram of the cores after the procedure confirmed the excision of microcalcifications. For the application of imprint cytology, the cores with microcalcifications confirmed by mammogram were gently rolled against glass microscope slides and thus imprint smears were made. For rapid preliminary diagnosis Diff-Quick stain, modified Papanicolaou stain and May Grunwald Giemsa were used. Afterwards, the core was dipped into a CytoRich Red Collection fluid for a few seconds in order to obtain samples with the use of the specimen wash. After the completion of cytological procedures, the core was prepared for routine histological study. The pathologist was blind to the preliminary cytological results. The cytological and pathological diagnoses were comparatively evaluated. According to the pathological examination, 73 lesions were benign, 15 lesions were carcinomas (12 ductal carcinomas in situ, 3 invasive ductal carcinomas), and 5 lesions were precursor: 3 cases of atypical ductal hyperplasia (ADH) and 2 cases of lobular neoplasia (LN). The observed sensitivity and specificity of the cytological imprints for cancer were 100% (one-sided, 97.5% CI: 78.2%-100%). Only one case of ADH could be detected by imprint cytology. Neither of the two LN cases was detected by the imprints. The imprints were uninformative in 11 out of 93 cases (11.8%). There was no uninformative case among women with malignancy. Imprint cytology provides a rapid, accurate preliminary diagnosis in a few minutes. This method might contribute to the diagnosis of early breast cancer and possibly attenuates patients' anxiety.

Evaluation of Prismo imprint.

DOT National Transportation Integrated Search

2009-05-01

The purpose of this research project is to evaluate the constructability and performance of Prismo Imprint synthetic overlays (manufacturer later changed to Ennis Paint, Inc.). Imprint is being evaluated as an alternative to brick pavers. This produc...

Genes Downregulated in Endometriosis Are Located Near the Known Imprinting Genes

PubMed Central

Higashiura, Yumi; Koike, Natsuki; Akasaka, Juria; Uekuri, Chiharu; Iwai, Kana; Niiro, Emiko; Morioka, Sachiko; Yamada, Yuki

2014-01-01

There is now accumulating evidence that endometriosis is a disease associated with an epigenetic disorder. Genomic imprinting is an epigenetic phenomenon known to regulate DNA methylation of either maternal or paternal alleles. We hypothesize that hypermethylated endometriosis-associated genes may be enriched at imprinted gene loci. We sought to determine whether downregulated genes associated with endometriosis susceptibility are associated with chromosomal location of the known paternally and maternally expressed imprinting genes. Gene information has been gathered from National Center for Biotechnology Information database geneimprint.com. Several researchers have identified specific loci with strong DNA methylation in eutopic endometrium and ectopic lesion with endometriosis. Of the 29 hypermethylated genes in endometriosis, 19 genes were located near 45 known imprinted foci. There may be an association of the genomic location between genes specifically downregulated in endometriosis and epigenetically imprinted genes. PMID:24615936

Triazine herbicide imprinted monolithic column for capillary electrochromatography.

PubMed

Aşır, Süleyman; Derazshamshir, Ali; Yılmaz, Fatma; Denizli, Adil

2015-12-01

Trietazine was selectively separated from aqueous solution containing the competitor molecule cyanazine, which is similar in size and shape to the template molecule. Structural features of the molecularly imprinted column were figured out by SEM. The influence of the mobile-phase composition, applied electrical field, and pH of the mobile phase on the recognition of trietazine by the imprinted monolithic polymer has been evaluated, and the imprint effect in the trietazine-imprinted monolithic polymer was demonstrated by an imprinting factor. The optimized monolithic column resulted in separation of trietazine from a structurally related competitor molecule, cyanazine. In addition, fast separation was obtained within 6 min by applying higher electrical field, with the electrophoretic mobility of 2.97 × 10(-8) m(2) V(-1) s(-1) at pH 11.0. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

[Parental genome imprinting].

PubMed

Babinet, C

1993-01-01

Genetical as well as experimental embryology methods have permitted, in recent years, to uncover a very important feature of mammalian embryonic development: it has been shown that female and male genomic complements are differentially imprinted in such a way that contribution of both a maternally and a paternally derived genome are absolutely necessary for the embryo to complete its normal development. Differential genomic imprinting seems therefore to impose some new and essential kind of information to the one already contained in the genomic sequences. The differential imprinting should be imposed on the genetic material during gametogenesis and persist throughout somatic development after fertilization. It should then be erased in the germ cell line and be established again in sperm and egg genomes. The recent discovery of several mouse genes which are imprinted should permit to address the question of the molecular mechanisms of imprinting.

Histopathology-like categories based on endometrial imprint cytology in dysfunctional uterine bleeding.

PubMed

Baxi, Seema N; Panchal, Nirav S

2015-01-01

Cytology of the endometrium is an underused technique in diagnostic pathology. It has been used in the past for endometrial hyperplasia and carcinoma. Only few studies have used cytology in the diagnosis of dysfunctional uterine bleeding (DUB). Endometrial imprint cytology has been rarely used except for application of immunocytochemistry in diagnosis of endometrial carcinoma. The present study was conducted to evaluate whether it is possible to assign histopathology-like diagnosis by imprint cytology and also to evaluate its usefulness in the assessment of patients of dysfunctional uterine bleeding of low clinical suspicion. Imprint smears were made from 93 curettage materials during a study of DUB. Blinded analysis of imprint smears was performed by using McKenzie's criteria and some criteria devised for the requirements of this study. Results of cytology were correlated with histopathology. Statistical analysis was carried out by GraphpadInStat Demo. Majority of the patterns classifiable in histopathology could also be classified in this study on imprint cytology. The overall sensitivity and specificity of cytology in the detection of endometrial patterns in DUB patients were 91.23% and 83.87%, respectively, although the sensitivities and specificities differ according to the phase of endometrium. Histopathology-like categories can be assigned on imprint smears in the diagnosis of DUB. Endometrial imprint cytology can be helpful in centers where histopathology laboratories are not available and even in well-established institutes. It is possible to improve the sensitivity and specificity with better imprinting techniques.

Preparation, Characterization and Application of a Molecularly Imprinted Polymer for Selective Recognition of Sulpiride

PubMed Central

Zhang, Wei; She, Xuhui; Wang, Liping; Fan, Huajun; Zhou, Qing; Huang, Xiaowen; Tang, James Z.

2017-01-01

A novel molecular imprinting polymer (MIP) was prepared by bulk polymerization using sulpiride as the template molecule, itaconic acid (ITA) as the functional monomer and ethylene glycol dimethacrylate (EGDMA) as the crosslinker. The formation of the MIP was determined as the molar ratio of sulpiride-ITA-EGDMA of 1:4:15 by single-factor experiments. The MIP showed good adsorption property with imprinting factor α of 5.36 and maximum adsorption capacity of 61.13 μmol/g, and was characterized by scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FT-IR) and surface area analysis. With the structural analogs (amisulpride, tiapride, lidocaine and cisapride) and small molecules containing a mono-functional group (p-toluenesulfonamide, formamide and 1-methylpyrrolidine) as substrates, static adsorption, kinetic adsorption, and rebinding experiments were also performed to investigate the selective adsorption ability, kinetic characteristic, and recognition mechanism of the MIP. A serial study suggested that the highly selective recognition ability of the MIP mainly depended on binding sites provided by N-functional groups of amide and amine. Moreover, the MIP as solid-phase extractant was successfully applied to extraction of sulpiride from the mixed solution (consisted of p-toluenesulfonamide, sulfamethoxazole, sulfanilamide, p-nitroaniline, acetanilide and trimethoprim) and serum sample, and extraction recoveries ranged from 81.57% to 86.63%. The tentative tests of drug release in stimulated intestinal fluid (pH 6.8) demonstrated that the tablet with the MIP–sulpiride could obviously inhibit sulpiride release rate. Thus, ITA-based MIP is an efficient and promising alternative to solid-phase adsorbent for extraction of sulpiride and removal of interferences in biosample analysis, and could be used as a potential carrier for controlled drug release. PMID:28772831

Physical Selectivity of Molecularly Imprinted polymers evaluated through free volume size distributions derived from Positron Lifetime Spectroscopy

NASA Astrophysics Data System (ADS)

Pasang, T.; Ranganathaiah, C.

2015-06-01

The technique of imprinting molecules of various sizes in a stable structure of polymer matrix has derived multitudes of applications. Once the template molecule is extracted from the polymer matrix, it leaves behind a cavity which is physically (size and shape) and chemically (functional binding site) compatible to the particular template molecule. Positron Annihilation Lifetime Spectroscopy (PALS) is a well known technique to measure cavity sizes precisely in the nanoscale and is not being used in the field of MIPs effectively. This method is capable of measuring nanopores and hence suitable to understand the physical selectivity of the MIPs better. With this idea in mind, we have prepared molecular imprinted polymers (MIPs) with methacrylicacid (MAA) as monomer and EGDMA as cross linker in different molar ratio for three different size template molecules, viz. 4-Chlorophenol (4CP)(2.29 Å), 2-Nephthol (2NP) (3.36 Å) and Phenolphthalein (PP) (4.47Å). FTIR and the dye chemical reactions are used to confirm the complete extraction of the template molecules from the polymer matrix. The free volume size and its distribution have been derived from the measured o-Ps lifetime spectra. Based on the free volume distribution analysis, the percentage of functional cavities for the three template molecules are determined. Percentage of functional binding cavities for 4-CP molecules has been found out to be 70.2% and the rest are native cavities. Similarly for 2NP it is 81.5% and nearly 100% for PP. Therefore, PALS method proves to be very precise and accurate for determining the physical selectivity of MIPs.

Preparation of imprinted cryogel cartridge for chiral separation of l-phenylalanine.

PubMed

Akgönüllü, Semra; Yavuz, Handan; Denizli, Adil

2017-06-01

l-Phe-imprinted cryogel cartridge was prepared for the chiral separation of l-Phe. N-Methacryloyl l-phenylalanine (MAPA) was used as a functional monomer for complexing with l-Phe. The selectivity of the membranes was investigated by using d-Phe, l-Trp, and d-Trp as competitor molecules. The PHEMAPA-l-Trp membranes were 6.4, 4.3, and 5.5 times more selective for l-Phe than d-Phe, l-Trp, and d-Trp, respectively. The PHEMAPA-l-Phe cryogel cartridge was incorporated into the fast protein liquid chromatography (FPLC) equipment and was able to separate D,l-Phe racemic mixture efficiently. The PHEMAPA-l-Phe membranes were shown to be reusable many times without significant loss of the adsorption capacity.

A Molecularly Imprinted Polymer (MIP)-Coated Microbeam MEMS Sensor for Chemical Detection

DTIC Science & Technology

2015-09-01

ARL-RP-0536 ● SEP 2015 US Army Research Laboratory A Molecularly Imprinted Polymer (MIP)- Coated Microbeam MEMS Sensor for...ARL-RP-0536 ● SEP 2015 US Army Research Laboratory A Molecularly Imprinted Polymer (MIP)- Coated Microbeam MEMS Sensor for Chemical...TITLE AND SUBTITLE A Molecularly Imprinted Polymer (MIP)-Coated Microbeam MEMS Sensor for Chemical Detection 5a. CONTRACT NUMBER 5b. GRANT NUMBER

Preparation of l-phenylalanine-imprinted solid-phase extraction sorbent by Pickering emulsion polymerization and the selective enrichment of l-phenylalanine from human urine.

PubMed

Li, Ji; Hu, Xiaoling; Guan, Ping; Zhang, Xiaoyan; Qian, Liwei; Zhang, Nan; Du, Chunbao; Song, Renyuan

2016-05-01

A novel l-phenylalanine molecularly imprinted solid-phase extraction sorbent was synthesized by the combination of Pickering emulsion polymerization and ion-pair dummy template imprinting. Compared to other polymerization methods, the molecularly imprinted polymers thus prepared exhibit a high specific surface, large pore diameter, and appropriate particle size. The key parameters for solid-phase extraction were optimized, and the result indicated that the molecularly imprinted polymer thus prepared exhibits a good recovery of 98.9% for l-phenylalanine. Under the optimized conditions of the procedure, an analytical method for l-phenylalanine was well established. By comparing the performance of the molecularly imprinted polymer and a commercial reverse-phase silica gel, the obtained molecularly imprinted polymer as an solid-phase extraction sorbent is more suitable, exhibiting high precision (relative standard deviation 3.2%, n = 4) and a low limit of detection (60.0 ± 1.9 nmol·L(-1) ) for the isolation of l-phenylalanine. Based on these results, the combination of the Pickering emulsion polymerization and ion-pair dummy template imprinting is effective for preparing selective solid-phase extraction sorbents for the separation of amino acids and organic acids from complex biological samples. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Transcriptome-wide investigation of genomic imprinting in chicken

PubMed Central

Frésard, Laure; Leroux, Sophie; Servin, Bertrand; Gourichon, David; Dehais, Patrice; Cristobal, Magali San; Marsaud, Nathalie; Vignoles, Florence; Bed'hom, Bertrand; Coville, Jean-Luc; Hormozdiari, Farhad; Beaumont, Catherine; Zerjal, Tatiana; Vignal, Alain; Morisson, Mireille; Lagarrigue, Sandrine; Pitel, Frédérique

2014-01-01

Genomic imprinting is an epigenetic mechanism by which alleles of some specific genes are expressed in a parent-of-origin manner. It has been observed in mammals and marsupials, but not in birds. Until now, only a few genes orthologous to mammalian imprinted ones have been analyzed in chicken and did not demonstrate any evidence of imprinting in this species. However, several published observations such as imprinted-like QTL in poultry or reciprocal effects keep the question open. Our main objective was thus to screen the entire chicken genome for parental-allele-specific differential expression on whole embryonic transcriptomes, using high-throughput sequencing. To identify the parental origin of each observed haplotype, two chicken experimental populations were used, as inbred and as genetically distant as possible. Two families were produced from two reciprocal crosses. Transcripts from 20 embryos were sequenced using NGS technology, producing ∼200 Gb of sequences. This allowed the detection of 79 potentially imprinted SNPs, through an analysis method that we validated by detecting imprinting from mouse data already published. However, out of 23 candidates tested by pyrosequencing, none could be confirmed. These results come together, without a priori, with previous statements and phylogenetic considerations assessing the absence of genomic imprinting in chicken. PMID:24452801

The "silent" imprint of musical training.

PubMed

Klein, Carina; Liem, Franziskus; Hänggi, Jürgen; Elmer, Stefan; Jäncke, Lutz

2016-02-01

Playing a musical instrument at a professional level is a complex multimodal task requiring information integration between different brain regions supporting auditory, somatosensory, motor, and cognitive functions. These kinds of task-specific activations are known to have a profound influence on both the functional and structural architecture of the human brain. However, until now, it is widely unknown whether this specific imprint of musical practice can still be detected during rest when no musical instrument is used. Therefore, we applied high-density electroencephalography and evaluated whole-brain functional connectivity as well as small-world topologies (i.e., node degree) during resting state in a sample of 15 professional musicians and 15 nonmusicians. As expected, musicians demonstrate increased intra- and interhemispheric functional connectivity between those brain regions that are typically involved in music perception and production, such as the auditory, the sensorimotor, and prefrontal cortex as well as Broca's area. In addition, mean connectivity within this specific network was positively related to musical skill and the total number of training hours. Thus, we conclude that musical training distinctively shapes intrinsic functional network characteristics in such a manner that its signature can still be detected during a task-free condition. Hum Brain Mapp 37:536-546, 2016. © 2015 Wiley Periodicals, Inc. © 2015 Wiley Periodicals, Inc.

Cultural relativism: maintenance of genomic imprints in pluripotent stem cell culture systems.

PubMed

Greenberg, Maxim Vc; Bourc'his, Déborah

2015-04-01

Pluripotent stem cells (PSCs) in culture have become a widely used model for studying events occurring during mammalian development; they also present an exciting avenue for therapeutics. However, compared to their in vivo counterparts, cultured PSC derivatives have unique properties, and it is well established that their epigenome is sensitive to medium composition. Here we review the specific effects on genomic imprints in various PSC types and culture systems. Imprinted gene regulation is developmentally important, and imprinting defects have been associated with several human diseases. Therefore, imprint abnormalities in PSCs may have considerable consequences for downstream applications. Copyright © 2015 Elsevier Ltd. All rights reserved.

Poly(1-vinylimidazole) functionalized magnetic ion imprinted polymer for fast and selective extraction of trace gold in geological, environmental and biological samples followed by graphite furnace atomic absorption spectrometry detection

NASA Astrophysics Data System (ADS)

Zhao, Bingshan; He, Man; Chen, Beibei; Xu, Hongrun; Hu, Bin

2018-05-01

In this study, poly(1-vinylimidazole) functionalized gold ion imprinted polymer coated magnetic nanoparticles (MNPs@PVIM-Au-IIP) were prepared and characterized. The adsorption behaviors of the prepared MNPs@PVIM-Au-IIP toward gold ions (Au(III)) were studied, it was found that MNPs@PVIM-Au-IIP has good selectivity, high adsorption capacity (185.4 mg g-1) and fast adsorption kinetic for Au(III). Based on it, a new method of ion imprinted magnetic solid phase extraction (II-MSPE) coupled with graphite furnace atomic absorption spectrometry (GFAAS) detection was proposed for the analysis of trace Au(III) in real samples with complicated matrix. Factors affecting MSPE including sample pH, desorption reagent, elution concentration and volume, elution time, sample volume and adsorption time were optimized. With high enrichment factor of 100-fold, the detection limit of the proposed method is 7.9 ng L-1 for Au(III) with the relative standard deviation of 7.4% (c = 50 ng L-1, n = 7). In order to validate the accuracy of the proposed method, the Certified Reference Material of GBW07293 geological sample (platinpalladium ore) was analyzed, and the determined value was in good agreement with the certified value. The proposed II-MSPE-GFAAS method is simple, fast, selective, sensitive and has been successfully applied in the determination of trace Au in ore, sediment, environmental water and human urine samples with satisfactory results.

Detection of Bisphenol A in aqueous medium by screen printed carbon electrodes incorporating electrochemical molecularly imprinted polymers.

PubMed

Ekomo, Vitalys Mba; Branger, Catherine; Bikanga, Raphaël; Florea, Ana-Mihaela; Istamboulie, Georges; Calas-Blanchard, Carole; Noguer, Thierry; Sarbu, Andrei; Brisset, Hugues

2018-07-30

Electrochemical molecularly imprinted polymers (e-MIPs) were for the first time introduced in screen-printed carbon electrodes (SPCE) as the sensing element for the detection of an organic pollutant. To play this sensing role, a redox tracer was incorporated inside the binding cavities of a cross-linked MIP, as a functional monomer during the synthesis step. Ferrocenylmethyl methacrylate was used for this purpose. It was associated with 4-vinylpyridine as a co-functional monomer and ethylene glycol dimethacrylate as cross-linker for the recognition of the endocrine disruptor, Bisphenol A (BPA), as a target. Microbeads of e-MIP and e-NIP (corresponding non-imprinted polymer) were obtained via precipitation polymerization in acetonitrile. The presence of ferrocene inside the polymers was assessed via FTIR and elemental analysis and the polymers microstructure was characterized by SEM and nitrogen adsorption/desorption experiments. Binding isotherms and batch selectivity experiments evidenced the presence of binding cavities inside the e-MIP and its high affinity for BPA compared to carbamazepine and ketoprofen. e-MIP (and e-NIP) microbeads were then incorporated in a graphite-hydroxyethylcellulose composite paste to prepare SPCE. Electrochemical properties of e-MIP-SPCE revealed a high sensitivity in the presence of BPA in aqueous medium compared to e-NIP-SPCE with a limit of detection (LOD) of 0.06 nM. Selectivity towards carbamazepine and ketoprofen was also observed with the e-MIP-SPCE. Copyright © 2018 Elsevier B.V. All rights reserved.

Does current reporting of lung function by the UK cystic fibrosis registry allow a fair comparison of adult centres?

PubMed

Nightingale, Julia Anne; Osmond, Clive

2017-09-01

Outcome data for UK cystic fibrosis centres are publicly available in an annual report, which ranks centres by median FEV 1 % predicted. We wished to assess whether there are differences in lung function outcomes between adult centres that might imply differing standards of care. UK Registry data from 4761 subjects at 34 anonymised adult centres were used to calculate mean FEV 1 % and rate of change of lung function for 2007-13. These measures were used to rank centres and compare outcomes. There are minor differences between centres for mean FEV 1 % for some years of the study and for rate of change of lung function over the study period. However, rankings are critically dependent on the outcome measure chosen and centre variation becomes negligible once patient population characteristics are taken into account. We have demonstrated that the ranking of centres is biased and any apparent difference in respiratory outcomes is unlikely to be related to differing standards of care between centres. Copyright © 2017 European Cystic Fibrosis Society. Published by Elsevier B.V. All rights reserved.

Imprinting can cause a maladaptive preference for infectious conspecifics

PubMed Central

2016-01-01

Recognizing and associating with specific individuals, such as conspecifics or kin, brings many benefits. One mechanism underlying such recognition is imprinting: the long-term memory of cues encountered during development. Typically, juveniles imprint on cues of nearby individuals and may later associate with phenotypes matching their ‘recognition template’. However, phenotype matching could lead to maladaptive social decisions if, for instance, individuals imprint on the cues of conspecifics infected with directly transmitted diseases. To investigate the role of imprinting in the sensory ecology of disease transmission, we exposed juvenile guppies, Poecilia reticulata, to the cues of healthy conspecifics, or to those experiencing disease caused by the directly transmitted parasite Gyrodactylus turnbulli. In a dichotomous choice test, adult ‘disease-imprinted’ guppies preferred to associate with the chemical cues of G. turnbulli-infected conspecifics, whereas ‘healthy-imprinted’ guppies preferred to associate with cues of uninfected conspecifics. These responses were only observed when stimulus fish were in late infection, suggesting imprinted fish responded to cues of disease, but not of infection alone. We discuss how maladaptive imprinting may promote disease transmission in natural populations of a social host. PMID:27072405

Molecularly Imprinted Intelligent Scaffolds for Tissue Engineering Applications.

PubMed

Neves, Mariana I; Wechsler, Marissa E; Gomes, Manuela E; Reis, Rui L; Granja, Pedro L; Peppas, Nicholas A

2017-02-01

The development of molecularly imprinted polymers (MIPs) using biocompatible production methods enables the possibility to further exploit this technology for biomedical applications. Tissue engineering (TE) approaches use the knowledge of the wound healing process to design scaffolds capable of modulating cell behavior and promote tissue regeneration. Biomacromolecules bear great interest for TE, together with the established recognition of the extracellular matrix, as an important source of signals to cells, both promoting cell-cell and cell-matrix interactions during the healing process. This review focuses on exploring the potential of protein molecular imprinting to create bioactive scaffolds with molecular recognition for TE applications based on the most recent approaches in the field of molecular imprinting of macromolecules. Considerations regarding essential components of molecular imprinting technology will be addressed for TE purposes. Molecular imprinting of biocompatible hydrogels, namely based on natural polymers, is also reviewed here. Hydrogel scaffolds with molecular memory show great promise for regenerative therapies. The first molecular imprinting studies analyzing cell adhesion report promising results with potential applications for cell culture systems, or biomaterials for implantation with the capability for cell recruitment by selectively adsorbing desired molecules.

Identification and resolution of artifacts in the interpretation of imprinted gene expression

PubMed Central

Proudhon, Charlotte

2010-01-01

Genomic imprinting refers to genes that are epigenetically programmed in the germline to express exclusively or preferentially one allele in a parent-of-origin manner. Expression-based genome-wide screening for the identification of imprinted genes has failed to uncover a significant number of new imprinted genes, probably because of the high tissue- and developmental-stage specificity of imprinted gene expression. A very large number of technical and biological artifacts can also lead to the erroneous evidence of imprinted gene expression. In this article, we focus on three common sources of potential confounding effects: (i) random monoallelic expression in monoclonal cell populations, (ii) genetically determined monoallelic expression and (iii) contamination or infiltration of embryonic tissues with maternal material. This last situation specifically applies to genes that occur as maternally expressed in the placenta. Beside the use of reciprocal crosses that are instrumental to confirm the parental specificity of expression, we provide additional methods for the detection and elimination of these situations that can be misinterpreted as cases of imprinted expression. PMID:20829207

Synthesis of magnetic molecularly imprinted polymers with excellent biocompatibility for the selective separation and inhibition of testosterone in prostate cancer cells.

PubMed

Tang, Xiaoshuang; Li, Feng; Jia, Jing; Yang, Chao; Liu, Wei; Jin, Ben; Wang, Xinyang; Gao, Ruixia; He, Dalin; Guo, Peng

2017-01-01

Androgen plays an important role in the progression of prostate cancer. In the present study, novel magnetic molecularly imprinted polymers (MMIPs) with good biocompatibility were produced for the selective separation and inhibition of testosterone in prostate cancer cells. MMIPs were prepared by using magnetic nanospheres, gelatin, and testosterone as the supporting materials, functional monomer, and the template molecule, respectively. The characterization of the resultant products was investigated by transmission electron microscopy, X-ray diffraction, and vibrating sample magnetometry. To test whether MMIPs can remove testosterone in biologic samples, human LNCaP (androgen-dependent) and C4-2 (androgen-independent) prostate cancer cells were selected as cell models. The translocation of androgen receptor (AR) was detected by immunofluorescence assay, and the expression of PSA mRNA was detected by real-time quantitative polymerase chain reaction analysis. Cell flow cytometry analysis was performed to detect cell cycle arrest. The synthesized nanomaterials (MMIPs) possessed high crystallinity, satisfactory superparamagnetic properties, and uniform imprinted shell, and exhibited high adsorption capacity, fast kinetics, and high selectivity for testosterone. Moreover, the obtained imprinted nanomaterials could selectively enrich and detect testosterone in the LNCaP cell samples as a solid-phase extractant coupled with high-performance liquid chromatography. In addition, the MMIPs could freely enter prostate cancer cells and suppress the translocation of AR into the cell nucleus. We further found that MMIPs inhibited upregulation of AR downstream target genes in LNCaP and C4-2 cells; also, MMIPs inhibited cell growth and induced obvious cell cycle arrest in androgen-dependent LNCaP cells, but had no obvious effect on androgen-independent C4-2 cells. Our results indicate that the obtained imprinted nanomaterials can specifically and effectively bind testosterone and recover it from prostate cancer cells. Moreover, the MMIPs can freely enter prostate cancer cells and block the activation of testosterone-AR pathway. Thus, the MMIPs may be a new option for antiandrogen therapy in prostate cancer.

Influence of Size and Shape of Silica Supports on the Sol⁻Gel Surface Molecularly Imprinted Polymers for Selective Adsorption of Gossypol.

PubMed

Zhi, Keke; Wang, Lulu; Zhang, Yagang; Jiang, Yingfang; Zhang, Letao; Yasin, Akram

2018-05-11

The influence of various silica gel supports with different shapes and sizes on the recognition properties of surface molecular imprinted polymers (MIPs) was investigated. MIPs for selective recognition and adsorption of gossypol were synthesized via the sol⁻gel process with a surface imprinting technique on silica gel substrates. 3-aminopropyltriethoxysilane (APTES) and tetraethoxysilane (TEOS) were chosen as the functional monomer and the cross-linker. The morphology and structure of the gossypol-MIPs were characterized using Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), and a standard Brunauer⁻Emett⁻Teller (BET) analysis. Results indicated that the surface imprinted polymer layer facilitated the removal and rebinding of the template, and thus, achieved fast binding kinetics. Compared with the MIPs prepared on irregularly shaped silica with a broad particle size distribution, the MIPs using regularly-shaped silica of uniform size showed higher imprinting factor (IF), and the MIP made with a relatively larger sized (60 μm) spherical silica, demonstrated higher adsorption capacity compared to the MIPs made with smaller sized, spherical silica. The MIP prepared with 60 μm spherically shaped silica, featured a fast adsorption kinetic of 10 min, and a saturated adsorption capacity of 204 mg·g −1 . The gossypol-MIP had higher selectivity (IF = 2.20) for gossypol over its structurally-similar analogs ellagic acid (IF = 1.13) and quercetin (IF = 1.20). The adsorption data of the MIP correlated well with the pseudo-second-order kinetic model and the Freundlich isotherm model, which implied that chemical adsorption dominated, and that multilayer adsorption occurred. Furthermore, the MIP exhibited an excellent regeneration performance, and the adsorption capacity of the MIP for gossypol only decreased by 6% after six reused cycles, indicating good application potential for selective adsorption of gossypol.

Influence of the Prader-Willi syndrome imprinting center on the DNA methylation landscape in the mouse brain

PubMed Central

Brant, Jason O; Riva, Alberto; Resnick, James L; Yang, Thomas P

2014-01-01

Reduced representation bisulfite sequencing (RRBS) was used to analyze DNA methylation patterns across the mouse brain genome in mice carrying a deletion of the Prader-Willi syndrome imprinting center (PWS-IC) on either the maternally- or paternally-inherited chromosome. Within the ∼3.7 Mb imprinted Angelman/Prader-Willi syndrome (AS/PWS) domain, 254 CpG sites were interrogated for changes in methylation due to PWS-IC deletion. Paternally-inherited deletion of the PWS-IC increased methylation levels ∼2-fold at each CpG site (compared to wild-type controls) at differentially methylated regions (DMRs) associated with 5′ CpG island promoters of paternally-expressed genes; these methylation changes extended, to a variable degree, into the adjacent CpG island shores. Maternal PWS-IC deletion yielded little or no changes in methylation at these DMRs, and methylation of CpG sites outside of promoter DMRs also was unchanged upon maternal or paternal PWS-IC deletion. Using stringent ascertainment criteria, ∼750,000 additional CpG sites were also interrogated across the entire mouse genome. This analysis identified 26 loci outside of the imprinted AS/PWS domain showing altered DNA methylation levels of ≥25% upon PWS-IC deletion. Curiously, altered methylation at 9 of these loci was a consequence of maternal PWS-IC deletion (maternal PWS-IC deletion by itself is not known to be associated with a phenotype in either humans or mice), and 10 of these loci exhibited the same changes in methylation irrespective of the parental origin of the PWS-IC deletion. These results suggest that the PWS-IC may affect DNA methylation at these loci by directly interacting with them, or may affect methylation at these loci through indirect downstream effects due to PWS-IC deletion. They further suggest the PWS-IC may have a previously uncharacterized function outside of the imprinted AS/PWS domain. PMID:25482058

Influence of the Prader-Willi syndrome imprinting center on the DNA methylation landscape in the mouse brain.

PubMed

Brant, Jason O; Riva, Alberto; Resnick, James L; Yang, Thomas P

2014-11-01

Reduced representation bisulfite sequencing (RRBS) was used to analyze DNA methylation patterns across the mouse brain genome in mice carrying a deletion of the Prader-Willi syndrome imprinting center (PWS-IC) on either the maternally- or paternally-inherited chromosome. Within the ~3.7 Mb imprinted Angelman/Prader-Willi syndrome (AS/PWS) domain, 254 CpG sites were interrogated for changes in methylation due to PWS-IC deletion. Paternally-inherited deletion of the PWS-IC increased methylation levels ~2-fold at each CpG site (compared to wild-type controls) at differentially methylated regions (DMRs) associated with 5' CpG island promoters of paternally-expressed genes; these methylation changes extended, to a variable degree, into the adjacent CpG island shores. Maternal PWS-IC deletion yielded little or no changes in methylation at these DMRs, and methylation of CpG sites outside of promoter DMRs also was unchanged upon maternal or paternal PWS-IC deletion. Using stringent ascertainment criteria, ~750,000 additional CpG sites were also interrogated across the entire mouse genome. This analysis identified 26 loci outside of the imprinted AS/PWS domain showing altered DNA methylation levels of ≥25% upon PWS-IC deletion. Curiously, altered methylation at 9 of these loci was a consequence of maternal PWS-IC deletion (maternal PWS-IC deletion by itself is not known to be associated with a phenotype in either humans or mice), and 10 of these loci exhibited the same changes in methylation irrespective of the parental origin of the PWS-IC deletion. These results suggest that the PWS-IC may affect DNA methylation at these loci by directly interacting with them, or may affect methylation at these loci through indirect downstream effects due to PWS-IC deletion. They further suggest the PWS-IC may have a previously uncharacterized function outside of the imprinted AS/PWS domain.

Ftx is dispensable for imprinted X-chromosome inactivation in preimplantation mouse embryos

PubMed Central

Soma, Miki; Fujihara, Yoshitaka; Okabe, Masaru; Ishino, Fumitoshi; Kobayashi, Shin

2014-01-01

X-chromosome inactivation (XCI) equalizes gene expression between the sexes by inactivating one of the two X chromosomes in female mammals. Xist has been considered as a major cis-acting factor that inactivates the paternally derived X chromosome (Xp) in preimplantation mouse embryos (imprinted XCI). Ftx has been proposed as a positive regulator of Xist. However, the physiological role of Ftx in female animals has never been studied. We recently reported that Ftx is located in the cis-acting regulatory region of the imprinted XCI and expressed from the inactive Xp, suggesting a role in the imprinted XCI mechanism. Here we examined the effects on imprinted XCI using targeted deletion of Ftx. Disruption of Ftx did not affect the survival of female embryos or expression of Xist and other X-linked genes in the preimplantation female embryos. Our results indicate that Ftx is dispensable for imprinted XCI in preimplantation embryos. PMID:24899465

Ftx is dispensable for imprinted X-chromosome inactivation in preimplantation mouse embryos.

PubMed

Soma, Miki; Fujihara, Yoshitaka; Okabe, Masaru; Ishino, Fumitoshi; Kobayashi, Shin

2014-06-05

X-chromosome inactivation (XCI) equalizes gene expression between the sexes by inactivating one of the two X chromosomes in female mammals. Xist has been considered as a major cis-acting factor that inactivates the paternally derived X chromosome (Xp) in preimplantation mouse embryos (imprinted XCI). Ftx has been proposed as a positive regulator of Xist. However, the physiological role of Ftx in female animals has never been studied. We recently reported that Ftx is located in the cis-acting regulatory region of the imprinted XCI and expressed from the inactive Xp, suggesting a role in the imprinted XCI mechanism. Here we examined the effects on imprinted XCI using targeted deletion of Ftx. Disruption of Ftx did not affect the survival of female embryos or expression of Xist and other X-linked genes in the preimplantation female embryos. Our results indicate that Ftx is dispensable for imprinted XCI in preimplantation embryos.

Pollen-imprinted polyurethanes for QCM allergen sensors.

PubMed

Jenik, Michael; Seifner, Alexandra; Lieberzeit, Peter; Dickert, Franz L

2009-05-01

Molecularly imprinted polymers for detecting plant pollen were designed as artificial recognition materials for quartz crystal microbalances in the gaseous phase. Imprints of birch (diameter, 25 mum) and nettle (diameter, 15 mum) pollen can be generated by polydimethylsiloxane stamping technique as proven by atomic force microscopy. If pollen grains are able to access the cavities and thus are incorporated, the resulting sensors display Sauerbrey-like negative frequency shifts. Non-Sauerbrey behaviour can be observed as soon as pollen is prevented from entering the selective hollows: this results in grain mobility on the electrode surface leading to frequency increases. Access to the cavities is determined by the diameter ratio between pollen grains and imprints as can be revealed during cross-selectivity measurements of nettle and birch pollen imprinted layers. When the amount of pollen grains on the electrode surface exceeds the number of available imprints, the excess particles move freely, resulting in positive, non-Sauerbrey frequency shifts.

Molecularly Imprinted Nanomaterials for Sensor Applications

PubMed Central

Irshad, Muhammad; Iqbal, Naseer; Mujahid, Adnan; Afzal, Adeel; Hussain, Tajamal; Sharif, Ahsan; Ahmad, Ejaz; Athar, Muhammad Makshoof

2013-01-01

Molecular imprinting is a well-established technology to mimic antibody-antigen interaction in a synthetic platform. Molecularly imprinted polymers and nanomaterials usually possess outstanding recognition capabilities. Imprinted nanostructured materials are characterized by their small sizes, large reactive surface area and, most importantly, with rapid and specific analysis of analytes due to the formation of template driven recognition cavities within the matrix. The excellent recognition and selectivity offered by this class of materials towards a target analyte have found applications in many areas, such as separation science, analysis of organic pollutants in water, environmental analysis of trace gases, chemical or biological sensors, biochemical assays, fabricating artificial receptors, nanotechnology, etc. We present here a concise overview and recent developments in nanostructured imprinted materials with respect to various sensor systems, e.g., electrochemical, optical and mass sensitive, etc. Finally, in light of recent studies, we conclude the article with future perspectives and foreseen applications of imprinted nanomaterials in chemical sensors. PMID:28348356

Synthesis and characterization of oxytetracycline imprinted magnetic polymer for application in food

NASA Astrophysics Data System (ADS)

Aggarwal, Sneha; Rajput, Yudhishthir Singh; Singh, Gulab; Sharma, Rajan

2016-02-01

Magnetic imprinted polymer was prepared by polymerization of methacrylate and ethyleneglycoldimethacrylate in the presence of oxytetracycline on the surface of iron magnetite. Selectivity of prepared polymer was calculated from ratio of partition coefficient of oxytetracycline for imprinted and non- imprinted polymer in water, acetonitrile, methanol and at different pH in aqueous buffer. pH of solvent exhibited pronounced effect on selectivity. Selectivity at pH 7.0, 6.0 and 5.0 was 36.0, 2.25 and 1.61 fold higher than at pH 4.0. Imprinted polymer was not selective for oxytetracycline in methanol. However, selectivity in water and acetonitrile was 19.42 and 2.86, respectively. Oxytetracycline did bind to imprinted polymer in water or aqueous buffer (pH 7.0) and could be eluted with methanol. Prepared polymer extracted 75-80 % oxytetracycline from water, honey and egg white.

A path planning method used in fluid jet polishing eliminating lightweight mirror imprinting effect

NASA Astrophysics Data System (ADS)

Li, Wenzong; Fan, Bin; Shi, Chunyan; Wang, Jia; Zhuo, Bin

2014-08-01

With the development of space technology, the design of optical system tends to large aperture lightweight mirror with high dimension-thickness ratio. However, when the lightweight mirror PV value is less than λ/10 , the surface will show wavy imprinting effect obviously. Imprinting effect introduced by head-tool pressure has become a technological barrier in high-precision lightweight mirror manufacturing. Fluid jet polishing can exclude outside pressure. Presently, machining tracks often used are grating type path, screw type path and pseudo-random path. On the edge of imprinting error, the speed of adjacent path points changes too fast, which causes the machine hard to reflect quickly, brings about new path error, and increases the polishing time due to superfluous path. This paper presents a new planning path method to eliminate imprinting effect. Simulation results show that the path of the improved grating path can better eliminate imprinting effect compared to the general path.

Genomic imprinting and dermatological disease.

PubMed

Millington, G W M

2006-09-01

Imprinting is the process whereby genetic alleles responsible for a phenotype are derived from one parent only. It is an epigenetic phenomenon resulting from DNA methylation or modification of protruding histones. When imprinted genes are disrupted, syndromes with characteristic patterns of inheritance and multisystem phenotype occur. Those detailed in this article have some quite characteristic cutaneous features and patterns of inheritance. These diseases include Beckwith-Wiedmann, Silver-Russell, Prader-Willi, McCune-Albright and Angelman syndromes, Albright's hereditary osteodystrophy, and progressive osseous heteroplasia. In the case of Von Hippel-Lindau syndrome, hypomelanosis of Ito and dermatopathia pigmentosa reticularis, imprinting may play a part in the inheritance. With neurofibromatosis type 1, a nonimprinted condition, the expression of the phenotype could be affected by interaction with imprinted gene loci. Imprinted genes could also play a part in the polygenetic inheritance of more common diseases also, as atopic eczema and psoriasis may have predominantly maternal and paternal modes of transmission, respectively.

Acylated-naproxen as the surface-active template in the preparation of micro- and nanospherical imprinted xerogels by emulsion techniques.

PubMed

Ornelas, Mariana; Azenha, Manuel; Araújo, Maria João; Marques, Eduardo F; Dias-Cabral, A C; Pereira, Carlos; Silva, A Fernando

2016-03-11

A strategy based on water-in-oil emulsion for the dispersion of a sol-gel mixture into small droplets was employed with the view of the production of naproxen-imprinted micro- and nanospheres. The procedure, aiming at a surface imprinting process, comprised the synthesis of a naproxen-derived surfactant. The imprinting process occurred at the interface of the emulsions or microemulsions, by the migration of the NAP-surfactant head into the sol-gel drops to leave surficial imprints due mainly to ion-pair interaction with a cationic group contained within the growing sol-gel network. The surface-imprinted microspheric particles exhibited a log-normal size distribution with geometric mean diameter of 3.1μm. A mesoporous texture was found from measurements of the specific surface area (206m(2)/g) and pore diameter (Dp 2nm). Evaluation of the microspheres as packed HPLC stationary phases resulted in the determination of the selectivity factor against ibuprofen (α=2.1), demonstrating the successful imprinting. Chromatographic efficiency, evaluated by the number of theoretical plates (222platescm(-3)), emerged as an outstanding feature among the set of all relatable formats produced before, an advantage intrinsic to the location of the imprinted sites on the surface. The material presented a capacity of 3.2μmolg(-1). Additionally, exploratory work conducted on their nanoscale counterparts resulted in the production of nanospheres in the size order of 10nm providing good indications of a successful imprinting process. Copyright © 2016 Elsevier B.V. All rights reserved.

Evaluation of Allelic Expression of Imprinted Genes in Adult Human Blood

PubMed Central

Frost, Jennifer M.; Monk, Dave; Stojilkovic-Mikic, Taita; Woodfine, Kathryn; Chitty, Lyn S.; Murrell, Adele; Stanier, Philip; Moore, Gudrun E.

2010-01-01

Background Imprinted genes are expressed from only one allele in a parent-of-origin dependent manner. Loss of imprinted (LOI) expression can result in a variety of human disorders and is frequently reported in cancer. Biallelic expression of imprinted genes in adult blood has been suggested as a useful biomarker and is currently being investigated in colorectal cancer. In general, the expression profiles of imprinted genes are well characterised during human and mouse fetal development, but not in human adults. Methodology/Principal Findings We investigated quantitative expression of 36 imprinted genes in adult human peripheral blood leukocytes obtained from healthy individuals. Allelic expression was also investigated in B and T lymphocytes and myeloid cells. We found that 21 genes were essentially undetectable in adult blood. Only six genes were demonstrably monoallelic, and most importantly, we found that nine genes were either biallelic or showed variable expression in different individuals. Separated leukocyte populations showed the same expression patterns as whole blood. Differential methylation at each of the imprinting control loci analysed was maintained, including regions that contained biallelically expressed genes. This suggests in some cases methylation has become uncoupled from its role in regulating gene expression. Conclusions/Significance We conclude that only a limited set of imprinted genes, including IGF2 and SNRPN, may be useful for LOI cancer biomarker studies. In addition, blood is not a good tissue to use for the discovery of new imprinted genes. Finally, lymphocyte DNA methylation status in the adult may not always be a reliable indicator of monoallelic gene expression. PMID:21042416

Imprinting of molecular recognition sites combined with π-donor-acceptor interactions using bis-aniline-crosslinked Au-CdSe/ZnS nanoparticles array on electrodes: Development of electrochemiluminescence sensor for the ultrasensitive and selective detection of 2-methyl-4-chlorophenoxyacetic acid.

PubMed

Yang, Yukun; Fang, Guozhen; Wang, Xiaomin; Liu, Guiyang; Wang, Shuo

2016-03-15

A novel strategy is reported for the fabrication of bis-aniline-crosslinked Au nanoparticles (NPs)-CdSe/ZnS quantum dots (QDs) array composite by facil one-step co-electropolymerization of thioaniline-functionalized AuNPs and thioaniline-functionalized CdSe/ZnS QDs onto thioaniline-functionalized Au elctrodes (AuE). Stable and enhanced cathodic electrochemiluminescence (ECL) of CdSe/ZnS QDs is observed on the modified electrode in neutral solution, suggesting promising applications in ECL sensing. An advanced ECL sensor is explored for detection of 2-methyl-4-chlorophenoxyacetic acid (MCPA) which quenches the ECL signal through electron-transfer pathway. The sensitive determination of MCPA with limit of detection (LOD) of 2.2 nmolL(-1) (S/N=3) is achieved by π-donor-acceptor interactions between MCPA and the bis-aniline bridging units. Impressively, the imprinting of molecular recognition sites into the bis-aniline-crosslinked AuNPs-CdSe/ZnS QDs array yields a functionalized electrode with an extremely sensitive response to MCPA in a linear range of 10 pmolL(-1)-50 μmolL(-1) with a LOD of 4.3 pmolL(-1 ()S/N=3). The proposed ECL sensor with high sensitivity, good selectivity, reproducibility and stability has been successfully applied for the determination of MCPA in real samples with satisfactory recoveries. In this study, ECL sensor combined the merits of QDs-ECL and molecularly imprinting technology is reported for the first time. The developed ECL sensor holds great promise for the fabrication of QDs-based ECL sensors with improved sensitivity and furthermore opens the door to wide applications of QDs-based ECL in food safety and environmental monitoring. Copyright © 2015 Elsevier B.V. All rights reserved.

From 3D to 2D: A Review of the Molecular Imprinting of Proteins

PubMed Central

Turner, Nicholas W.; Jeans, Christopher W.; Brain, Keith R.; Allender, Christopher J.; Hlady, Vladimir; Britt, David W.

2008-01-01

Molecular imprinting is a generic technology that allows for the introduction of sites of specific molecular affinity into otherwise homogeneous polymeric matrices. Commonly this technique has been shown to be effective when targeting small molecules of molecular weight <1500, while extending the technique to larger molecules such as proteins has proven difficult. A number of key inherent problems in protein imprinting have been identified, including permanent entrapment, poor mass transfer, denaturation, and heterogeneity in binding pocket affinity, which have been addressed using a variety of approaches. This review focuses on protein imprinting in its various forms, ranging from conventional bulk techniques to novel thin film and monolayer surface imprinting approaches. PMID:17137293

From 3D to 2D: a review of the molecular imprinting of proteins.

PubMed

Turner, Nicholas W; Jeans, Christopher W; Brain, Keith R; Allender, Christopher J; Hlady, Vladimir; Britt, David W

2006-01-01

Molecular imprinting is a generic technology that allows for the introduction of sites of specific molecular affinity into otherwise homogeneous polymeric matrices. Commonly this technique has been shown to be effective when targeting small molecules of molecular weight <1500, while extending the technique to larger molecules such as proteins has proven difficult. A number of key inherent problems in protein imprinting have been identified, including permanent entrapment, poor mass transfer, denaturation, and heterogeneity in binding pocket affinity, which have been addressed using a variety of approaches. This review focuses on protein imprinting in its various forms, ranging from conventional bulk techniques to novel thin film and monolayer surface imprinting approaches.

Acoustic imprinting leads to differential 2-deoxy-D-glucose uptake in the chick forebrain.

PubMed Central

Maier, V; Scheich, H

1983-01-01

This report describes experiments in which successful acoustic imprinting correlates with differential uptake of D-2-deoxy[14C]glucose in particular forebrain areas that are not considered primarily auditory. Newly hatched guinea chicks (Numida meleagris meleagris) were imprinted by playing 1.8-kHz or 2.5-kHz tone bursts for prolonged periods. Those chicks were considered to be imprinted who approached the imprinting stimulus (emitted from a loudspeaker) and preferred it over a new stimulus in a simultaneous discrimination test. In the 2-deoxy-D-glucose experiment all chicks, imprinted and naive, were exposed to 1.8-kHz tone bursts for 1 hr. As shown by the autoradiographic analysis of the brains, neurons in the 1.8-kHz isofrequency plane of the auditory "cortex" (field L) were activated in all chicks, whether imprinted or not. However, in the most rostral forebrain striking differences were found. Imprinted chicks showed an increased 2-deoxy-D-glucose uptake in three areas, as compared to naive chicks: (i) the lateral neostriatum and hyperstriatum ventrale, (ii) a medial magnocellular field (medial neostriatum/hyperstriatum ventrale), and (iii) the most dorsal layers of the hyperstriatum. Based on these findings we conclude that these areas are involved in the processing of auditory stimuli once they have become meaningful by experience. Images PMID:6574519

[Neurobiology of imprinting].

PubMed

Ohki-Hamazaki, Hiroko

2012-06-01

Imprinting is an example of learning and memory acquisition in infancy. In the case of precocial birds, such as geese, ducks, and chickens, the baby birds learn the characteristics of the first moving object that they see within a critical period, and they imprint on it and follow it around. We analyzed the neural basis of this behavior in order to understand the neural mechanism of learning and memory in infancy. Information pertaining to a visual imprinting stimulus is recognized and processed in the visual Wulst, a region that corresponds to the mammalian visual cortex. It is then transmitted to the posterior region of the telencephalon, followed by the core region of the hyperpallium densocellulare (HDCo), periventricular region of the hyperpallium densocellulare (HDPe), and finally, the intermediate medial mesopallium (IMM), a region similar to the mammalian association cortex. Memory is stored in the IMM. After imprint training, plastic changes are observed in the visual Wulst as well as in the neurons of this circuit. HDCo cells, located at the center of this circuit, express N-methyl-D-aspartate (NMDA) receptors containing the NMDA receptor (NR) 2B subunit; the expression of this receptor increased after the imprint training. Inhibition of this receptor in the cells of the HDCo region leads to failure of imprinting and inactivation of this circuit. Thus, NMDA receptors bearing the NR2B subunit play a critical role in plastic changes in this circuit and in induction of imprinting.

Molecularly imprinted polymeric stir bar: Preparation and application for the determination of naftopidil in plasma and urine samples.

PubMed

Peng, Jun; Xiao, Deli; He, Hua; Zhao, Hongyan; Wang, Cuixia; Shi, Tian; Shi, Kexin

2016-01-01

In this study, molecularly imprinting technology and stir bar absorption technology were combined to develop a microextraction approach based on a molecularly imprinted polymeric stir bar. The molecularly imprinted polymer stir bar has a high performance, is specific, economical, and simple to prepare. The obtained naftopidil-imprinted polymer-coated bars could simultaneously agitate and adsorb naftopidil in the sample solution. The ratio of template/monomer/cross-linker and conditions of template removal were optimized to prepare a stir bar with highly efficient adsorption. Fourier transform infrared spectroscopy, scanning electron microscopy, selectivity, and extraction capacity experiments showed that the molecularly imprinted polymer stir bar was prepared successfully. To utilize the molecularly imprinted polymer stir bar for the determination of naftopidil in complex body fluid matrices, the extraction time, stirring speed, eluent, and elution time were optimized. The limits of detection of naftopidil in plasma and urine sample were 7.5 and 4.0 ng/mL, respectively, and the recoveries were in the range of 90-112%. The within-run precision and between-run precision were acceptable (relative standard deviation <7%). These data demonstrated that the molecularly imprinted polymeric stir bar based microextraction with high-performance liquid chromatography was a convenient, rapid, efficient, and specific method for the precise determination of trace naftopidil in clinical analysis. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Epigenetic effects of methoxychlor and vinclozolin on male gametes.

PubMed

Paoloni-Giacobino, Ariane

2014-01-01

Imprinting is an epigenetic form of gene regulation that mediates a parent-of-origin-dependent expression of the alleles of a number of genes. Imprinting, which occurs at specific sites within or surrounding the gene, called differentially methylated domains, consists in a methylation of CpGs. The appropriate transmission of genomics imprints is essential for the control of embryonic development and fetal growth. A number of endocrine disruptors (EDs) affect male reproductive tract development and spermatogenesis. It was postulated that the genetic effects of EDs might be induced by alterations in gene imprinting. We tested two EDs: methoxychlor and vinclozolin. Their administration during gestation induced in the offspring a decrease in sperm counts and significant modifications in the methylation pattern of a selection of paternally and maternally expressed canonical imprinted genes. The observation that imprinting was largely untouched in somatic cells suggests that EDs exert their damaging effects via the process of reprogramming that is unique to gamete development. Interestingly, the effects were transgenerational, although disappearing gradually from F1 to F3. A systematic analysis showed a heterogeneity in the CpG sensitivity to EDs. We propose that the deleterious effects of EDs on the male reproductive system are mediated by imprinting defects in the sperm. The reported effects of EDs on human male spermatogenesis might be mediated by analogous imprinting alterations. © 2014 Elsevier Inc. All rights reserved.

Surface-imprinted microspheres prepared by a template-oriented method for the chiral separation of amlodipine.

PubMed

Lai, Shenzhi; Ouyang, Xiaoli; Cai, Changqun; Xu, Wensheng; Chen, Chunyan; Chen, Xiaoming

2017-05-01

The surface imprinting technique has been developed to overcome the mass-transfer difficulty, but the utilization ratio of template molecules in the imprinting procedure still remains a challengeable task to be improved. In this work, specifically designed surface-imprinted microspheres were prepared by a template-oriented method for enantioseparation of amlodipine besylate. Submicron mesoporous silica microspheres were surface-modified with double bonds, followed by polymerizing methacrylic acid to generate carboxyl modified mesoporous silica microspheres (PMAA@SiO 2 ). Afterwards, PMAA@SiO 2 was densely adsorbed with (S)-amlodipine molecules to immobilize template molecules through multiple hydrogen bonding interactions. Then surface molecular imprinting was carried out by cross-linking the carboxyl group of PMAA@SiO 2 with ethylene glycol diglycidyl ether. The surface-imprinted microspheres showed fast binding kinetics of only 20 min for equilibrium adsorption, and the saturation adsorption capacity reached 137 mg/g. The imprinted materials displayed appreciable chiral separation ability when used as column chromatography for enantioseparation of amlodipine from amlodipine besylate, and the enantiomeric excess of (S)-amlodipine reached 13.8% with only 2.3 cm column length by no extra chiral additives. Besides, the imprinted materials exhibited excellent reusability, and this allows the potential application for amplification production of amlodipine enantiomer. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Defect reduction for semiconductor memory applications using jet and flash imprint lithography

NASA Astrophysics Data System (ADS)

Ye, Zhengmao; Luo, Kang; Lu, Xiaoming; Fletcher, Brian; Liu, Weijun; Xu, Frank; LaBrake, Dwayne; Resnick, Douglas J.; Sreenivasan, S. V.

2012-07-01

Acceptance of imprint lithography for manufacturing will require demonstration that it can attain defect levels commensurate with the defect specifications of high-end memory devices. Defects occurring during imprinting can generally be broken into two categories; random defects and repeating defects. Examples of random defects include fluid phase imprint defects, such as bubbles, and solid phase imprint defects, such as line collapse. Examples of repeater defects include mask fabrication defects and particle induced defects. Previous studies indicated that soft particles cause nonrepeating defects. Hard particles, on the other hand, can cause either permanent resist plugging or mask damage. In a previous study, two specific defect types were examined; random nonfill defects occurring during the resist filling process and repeater defects caused by interactions with particles on the substrate. We attempted to identify the different types of imprint defect types using a mask with line/space patterns at dimensions as small as 26 nm. An Imprio 500 twenty-wafer per hour development tool was used to study the various defect types. The imprint defect density was reduced nearly four orders of magnitude, down to ˜4/cm2 in a period of two years following the availability of low defect imprint masks at 26-nm half-pitch. This reduction was achieved by identifying the root cause of various defects and then taking the appropriate corrective action.

A needle extraction utilizing a molecularly imprinted-sol-gel xerogel for on-line microextraction of the lung cancer biomarker bilirubin from plasma and urine samples.

PubMed

Moein, Mohammad Mahdi; Jabbar, Dunia; Colmsjö, Anders; Abdel-Rehim, Mohamed

2014-10-31

In the present work, a needle trap utilizing a molecularly imprinted sol-gel xerogel was prepared for the on-line microextraction of bilirubin from plasma and urine samples. Each prepared needle could be used for approximately one hundred extractions before it was discarded. Imprinted and non-imprinted sol-gel xerogel were applied for the extraction of bilirubin from plasma and urine samples. The produced molecularly imprinted sol-gel xerogel polymer showed high binding capacity and fast adsorption/desorption kinetics for bilirubin in plasma and urine samples. The adsorption capacity of molecularly imprinted sol-gel xerogel polymer was approximately 60% higher than that of non-imprinted polymer. The effect of the conditioning, washing and elution solvents, pH, extraction time, adsorption capacity and imprinting factor were investigated. The limit of detection and the lower limit of quantification were set to 1.6 and 5nmolL(-1), respectively using plasma or urine samples. The standard calibration curves were obtained within the concentration range of 5-1000nmolL(-1) in both plasma and urine samples. The coefficients of determination values (R(2)) were ≥0.998 for all runs. The extraction recovery was approximately 80% for BR in the human plasma and urine samples. Copyright © 2014 Elsevier B.V. All rights reserved.

Culture of preimplantation mouse embryos affects fetal development and the expression of imprinted genes.

PubMed

Khosla, S; Dean, W; Brown, D; Reik, W; Feil, R

2001-03-01

Culture of preimplantation mammalian embryos and cells can influence their subsequent growth and differentiation. Previously, we reported that culture of mouse embryonic stem cells is associated with deregulation of genomic imprinting and affects the potential for these cells to develop into normal fetuses. The purpose of our current study was to determine whether culture of preimplantation mouse embryos in a chemically defined medium (M16) with or without fetal calf serum (FCS) can affect their subsequent development and imprinted gene expression. Only one third of the blastocysts that had been cultured from two-cell embryos in M16 medium complemented with FCS developed into viable Day 14 fetuses after transfer into recipients. These M16 + FCS fetuses were reduced in weight as compared with controls and M16 fetuses and had decreased expression of the imprinted H19 and insulin-like growth factor 2 genes associated with a gain of DNA methylation at an imprinting control region upstream of H19. They also displayed increased expression of the imprinted gene Grb10. The growth factor receptor binding gene Grb7, in contrast, was strongly reduced in its expression in most of the M16 + FCS fetuses. No alterations were detected for the imprinted gene MEST: Preimplantation culture in the presence of serum can influence the regulation of multiple growth-related imprinted genes, thus leading to aberrant fetal growth and development.

Molecularly imprinted solid-phase extraction combined with high performance liquid chromatography for analysis of phenolic compounds from environmental water samples.

PubMed

Feng, Qin-Zhong; Zhao, Li-Xia; Yan, Wei; Lin, Jin-Ming; Zheng, Zhi-Xia

2009-08-15

The molecularly imprinted bulk polymer with 2,4,6-trichlorophenol (2,4,6-TCP) as the template molecule and methylacrylic acid (MAA), ethylene glycol dimethacrylate (EGDMA) as functional monomer and the crosslinker, respectively, has been prepared and applied to the molecularly imprinted solid-phase extraction (MISPE) procedure for selective preconcentration of phenolic compounds from environmental water samples. Various parameters affecting the extraction efficiency of the polymer have been evaluated to optimize the selective preconcentration of the phenolic compounds from aqueous samples. The characteristics of the MISPE method were validated by HPLC. The recoveries ranged between 90% and 98% (RSD: 0.9-2.3%, n=3) for tap water, between 85% and 105% (RSD: 2.6-4.9%, n=3) for river water, between 78% and 98% (RSD: 2.6-5.4%, n=3) for sewage water fortified with 0.4 mg L(-1) of phenol, 4-chlorophenol (4-CP), 2,4-dichlorophenol (2,4-DCP), pentachlorophenol (PCP). It was demonstrated that this MISPE-HPLC method could be applied to direct preconcentration and determination of phenolic compounds in environmental water samples.

Enhancing the Activity of Peptide-Based Artificial Hydrolase with Catalytic Ser/His/Asp Triad and Molecular Imprinting.

PubMed

Wang, Mengfan; Lv, Yuqi; Liu, Xiaojing; Qi, Wei; Su, Rongxin; He, Zhimin

2016-06-08

In this study, an artificial hydrolase was developed by combining the catalytic Ser/His/Asp triad with N-fluorenylmethoxycarbonyl diphenylalanine (Fmoc-FF), followed by coassembly of the peptides into nanofibers (CoA-HSD). The peptide-based nanofibers provide an ideal supramolecular framework to support the functional groups. Compared with the self-assembled catalytic nanofibers (SA-H), which contain only the catalytic histidine residue, the highest activity of CoA-HSD occurs when histidine, serine, and aspartate residues are at a ratio of 40:1:1. This indicates that the well-ordered nanofiber structure and the synergistic effects of serine and aspartate residues contribute to the enhancement in activity. Additionally, for the first time, molecular imprinting was applied to further enhance the activity of the peptide-based artificial enzyme (CoA-HSD). p-NPA was used as the molecular template to arrange the catalytic Ser/His/Asp triad residues in the proper orientation. As a result, the activity of imprinted coassembled CoA-HSD nanofibers is 7.86 times greater than that of nonimprinted CoA-HSD and 13.48 times that of SA-H.

Molecularly imprinted solid-phase extraction for determination of tilmicosin in feed using high performance liquid chromatography.

PubMed

Zheng, Yaqiu; Liu, Yahong; Guo, Hongbin; He, Limin; Fang, Binghu; Zeng, Zhenling

2011-04-01

A simple, sensitive and reproducible molecularly imprinted solid-phase extraction (MISPE) coupled with high performance liquid chromatographic method was developed for monitoring tilmicosin in feeds. The polymers were prepared using tylosin as mimic template molecule, methacrylic acid as functional monomer and ethylene glycol dimethacrylate as cross-linking monomer, and chloroform as a solvent by bulk polymerization. Under the optimum MISPE conditions, the novel polymer sorbent can selectively extract and enrich tilmicosin from variety of feeds. The MISPE cartridge was better than non-imprinted, C(18) and HLB cartridges in terms of both recovery and precision. Mean recoveries of tilmicosin from five kinds of feeds spiked at 1, 10 and 50 mg kg(-1) ranged from 76.9% to 95.6%, with intra-day and inter-day relative standard deviation less than 7.6%. The linearity was ranged from 1.0 to 100 mg L(-1) for matrix standard solution (r=0.9990). The limit of detection was approximately 0.35 mg kg(-1) and the limit of quantification was approximately 0.98 mg kg(-1). There was cleaner chromatogram by using MISPE than C(18) and HLB SPE. Copyright © 2011 Elsevier B.V. All rights reserved.

Boronic acid based imprinted electrochemical sensor for rutin recognition and detection.

PubMed

Wang, Chunlei; Wang, Qi; Zhong, Min; Kan, Xianwen

2016-10-21

Multi-walled carbon nanotubes (MWNTs) and boronic acid based molecular imprinting polymer (MIP) were successively modified on a glassy carbon electrode surface to fabricate a novel electrochemical sensor for rutin recognition and detection. 3-Aminophenylboronic acid (APBA) was chosen as a monomer for the electropolymerization of MIP film in the presence of rutin. In addition to the imprinted cavities in MIP film to complement the template molecule in shape and functional groups, the high affinity between the boronic acid group of APBA and vicinal diols of rutin also enhanced the selectivity of the sensor, which made the sensor display a good selectivity to rutin. Moreover, the modified MWNTs improved the sensitivity of the sensor for rutin detection. The mole ratios of rutin and APBA, electropolymerized scan cycles and rates, and pH value of the detection solution were optimized. Under optimal conditions, the sensor was used to detect rutin in a linear range from 4.0 × 10 -7 to 1.0 × 10 -5 mol L -1 with a detection limit of 1.1 × 10 -7 mol L -1 . The sensor has also been applied to assay rutin in tablets with satisfactory results.

Deletions and epimutations affecting the human 14q32.2 imprinted region in individuals with paternal and maternal upd(14)-like phenotypes.

PubMed

Kagami, Masayo; Sekita, Yoichi; Nishimura, Gen; Irie, Masahito; Kato, Fumiko; Okada, Michiyo; Yamamori, Shunji; Kishimoto, Hiroshi; Nakayama, Masahiro; Tanaka, Yukichi; Matsuoka, Kentarou; Takahashi, Tsutomu; Noguchi, Mika; Tanaka, Yoko; Masumoto, Kouji; Utsunomiya, Takeshi; Kouzan, Hiroko; Komatsu, Yumiko; Ohashi, Hirofumi; Kurosawa, Kenji; Kosaki, Kenjirou; Ferguson-Smith, Anne C; Ishino, Fumitoshi; Ogata, Tsutomu

2008-02-01

Human chromosome 14q32.2 carries a cluster of imprinted genes including paternally expressed genes (PEGs) such as DLK1 and RTL1 and maternally expressed genes (MEGs) such as MEG3 (also known as GTL2), RTL1as (RTL1 antisense) and MEG8 (refs. 1,2), together with the intergenic differentially methylated region (IG-DMR) and the MEG3-DMR. Consistent with this, paternal and maternal uniparental disomy for chromosome 14 (upd(14)pat and upd(14)mat) cause distinct phenotypes. We studied eight individuals (cases 1-8) with a upd(14)pat-like phenotype and three individuals (cases 9-11) with a upd(14)mat-like phenotype in the absence of upd(14) and identified various deletions and epimutations affecting the imprinted region. The results, together with recent mouse data, imply that the IG-DMR has an important cis-acting regulatory function on the maternally inherited chromosome and that excessive RTL1 expression and decreased DLK1 and RTL1 expression are relevant to upd(14)pat-like and upd(14)mat-like phenotypes, respectively.

Molecular Imprinting Technology in Quartz Crystal Microbalance (QCM) Sensors

PubMed Central

Emir Diltemiz, Sibel; Keçili, Rüstem; Ersöz, Arzu; Say, Rıdvan

2017-01-01

Molecularly imprinted polymers (MIPs) as artificial antibodies have received considerable scientific attention in the past years in the field of (bio)sensors since they have unique features that distinguish them from natural antibodies such as robustness, multiple binding sites, low cost, facile preparation and high stability under extreme operation conditions (higher pH and temperature values, etc.). On the other hand, the Quartz Crystal Microbalance (QCM) is an analytical tool based on the measurement of small mass changes on the sensor surface. QCM sensors are practical and convenient monitoring tools because of their specificity, sensitivity, high accuracy, stability and reproducibility. QCM devices are highly suitable for converting the recognition process achieved using MIP-based memories into a sensor signal. Therefore, the combination of a QCM and MIPs as synthetic receptors enhances the sensitivity through MIP process-based multiplexed binding sites using size, 3D-shape and chemical function having molecular memories of the prepared sensor system toward the target compound to be detected. This review aims to highlight and summarize the recent progress and studies in the field of (bio)sensor systems based on QCMs combined with molecular imprinting technology. PMID:28245588

Preparation of bio-based keratin-derived magnetic molecularly imprinted polymer nanoparticles for the facile and selective separation of bisphenol A from water.

PubMed

Hassanzadeh, Marjan; Ghaemy, Mousa

2018-02-21

In this study, new bio-based magnetic molecularly imprinted polymer nanoparticles (∼23 nm) were synthesized from keratin extracted from chicken feathers and methacrylate-functionalized Fe 3 O 4 nanoparticles for its potential application in separation and removal of bisphenol A from water. The prepared magnetic molecularly imprinted polymer was characterized by Fourier-transform infrared spectroscopy, field-emission scanning electron microscopy, thermogravimetric analysis, alternative gradient field magnetometry, and energy-dispersive X-ray spectroscopy. The sorption of bisphenol A was investigated by changing the influencing factors such as pH, immersion time, Fe 3 O 4 nanoparticles dosage, and the initial concentration of bisphenol A. Results illustrated that sorption was very fast and efficient (Q m  = 600 mg/g) having a removal efficiency of ∼98% in 40 min of immersion. The adsorption process showed better conformity with the Weber-Morris kinetics and the Freundlich isotherm model. The selectivity of bisphenol A by adsorbent was checked in the presence of hydroquinone, phenol, tetrabromobisphenol, and 4,4'-biphenol as interferences. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

48 CFR 31.205-1 - Public relations and advertising costs.

Code of Federal Regulations, 2010 CFR

2010-10-01

... Organizations 31.205-1 Public relations and advertising costs. (a) Public relations means all functions and... public relations and advertising costs include the following: (1) All public relations and advertising..., imprinted clothing, buttons, and other mementos provided to customers or the public. (7) Costs of...

Electropolymerized molecularly imprinted polypyrrole film for sensing of clofibric acid.

PubMed

Schweiger, Bianca; Kim, Jungtae; Kim, Young Jun; Ulbricht, Mathias

2015-02-26

Piezoelectric quartz crystals and analogous gold substrates were electrochemically coated with molecularly imprinted polypyrrole films for pulsed amperometric detection (PAD) of clofibric acid, a metabolite of clofibrate. Cyclic voltammetry data obtained during polymerization and deposited weight estimations revealed a decrease of the polymerization rate with increasing clofibric acid concentration. XPS measurements indicated that clofibric acid could be removed after imprinting with an aqueous ethanol solution, which was further optimized by using PAD. Zeta potential and contact angle measurements revealed differences between molecularly imprinted (MIP) and non-imprinted polymer (NIP) layers. Binding experiments with clofibric acid and other substances showed a pronounced selectivity of the MIP for clofibric acid vs. carbamazepine, but the response of MIP and NIP to 2,4-dichlorophenoxyacetic acid was higher than that for clofibric acid. A smooth surface, revealed by AFM measurements, with roughness of 6-8 nm for imprinted and non-imprinted layers, might be a reason for an excessively low density of specific binding sites for clofibric acid. Furthermore, the decreased polymerization rate in the presence of clofibric acid might not result in well-defined polymer structures, which could be the reason for the lower sensitivity.

Electropolymerized Molecularly Imprinted Polypyrrole Film for Sensing of Clofibric Acid

PubMed Central

Schweiger, Bianca; Kim, Jungtae; Kim, Young Jun; Ulbricht, Mathias

2015-01-01

Piezoelectric quartz crystals and analogous gold substrates were electrochemically coated with molecularly imprinted polypyrrole films for pulsed amperometric detection (PAD) of clofibric acid, a metabolite of clofibrate. Cyclic voltammetry data obtained during polymerization and deposited weight estimations revealed a decrease of the polymerization rate with increasing clofibric acid concentration. XPS measurements indicated that clofibric acid could be removed after imprinting with an aqueous ethanol solution, which was further optimized by using PAD. Zeta potential and contact angle measurements revealed differences between molecularly imprinted (MIP) and non-imprinted polymer (NIP) layers. Binding experiments with clofibric acid and other substances showed a pronounced selectivity of the MIP for clofibric acid vs. carbamazepine, but the response of MIP and NIP to 2,4-dichlorophenoxyacetic acid was higher than that for clofibric acid. A smooth surface, revealed by AFM measurements, with roughness of 6–8 nm for imprinted and non-imprinted layers, might be a reason for an excessively low density of specific binding sites for clofibric acid. Furthermore, the decreased polymerization rate in the presence of clofibric acid might not result in well-defined polymer structures, which could be the reason for the lower sensitivity. PMID:25730487

Molecularly imprinted polymer based quartz crystal microbalance sensor system for sensitive and label-free detection of synthetic cannabinoids in urine.

PubMed

Battal, Dilek; Akgönüllü, Semra; Yalcin, M Serkan; Yavuz, Handan; Denizli, Adil

2018-07-15

Herein, we prepared a novel quartz crystal microbalance (QCM) sensor for synthetic cannabinoids (JWH-073, JWH-073 butanoic acid, JWH-018 and JWH-018 pentanoic acid,) detection. Firstly, the synthetic cannabinoid (SCs) imprinted (MIP) and non-imprinted (NIP) nanoparticles were synthesized by mini-emulsion polymerization system. The SCs-imprinted nanoparticles were first characterized by SEM, TEM, zeta-size and FTIR-ATR analysis and then were dropped onto the gold QCM surface. The SCs-imprinted QCM sensor was characterized by an ellipsometer, contact angle, and AFM. The limit of detection was found as 0.3, 0.45, 0.4, 0.2 pg/mL JWH-018, JWH-073, JWH-018 pentanoic acid and JWH-073 butanoic acid, respectively. The selectivity of the SCs-imprinted QCM sensor was shown by using JWH-018, JWH-018 pentanoic acid, JWH-073 and JWH-073 butanoic acid. According to the results, the SCs-imprinted QCM sensors show highly selective and sensitive in a broad range of synthetic cannabinoid concentrations (0.0005-1.0 ng/mL) in both aqueous and synthetic urine solutions. Copyright © 2018 Elsevier B.V. All rights reserved.

One-by-one imprinting in two eccentric layers of hollow core-shells: Sequential electroanalysis of anti-HIV drugs.

PubMed

Singh, Kislay; Jaiswal, Swadha; Singh, Richa; Fatma, Sana; Prasad, Bhim Bali

2018-07-15

Double layered one-by-one imprinted hollow core-shells@ pencil graphite electrode was fabricated for sequential sensing of anti-HIV drugs. For this, two eccentric layers were developed on the surface of vinylated silica nanospheres to obtain double layered one-by-one imprinted solid core-shells. This yielded hollow core-shells on treatment with hydrofluoric acid. The modified hollow core-shells (single layered dual imprinted) evolved competitive diffusion of probe/analyte molecules. However, the corresponding double layered one-by-one imprinted hollow core-shells (outer layer imprinted with Zidovudine, and inner layer with Lamivudine) were found relatively better owing to their bilateral diffusions into molecular cavities, without any competition. The entire work is based on differential pulse anodic stripping voltammetry at double layered one-by-one imprinted hollow core-shells. This resulted in indirect detection of electro inactive targets with limits of detection as low as 0.91 and 0.12 (aqueous sample), 0.94 and 0.13 (blood serum), and 0.99 and 0.20 ng mL -1 (pharmaceutics) for lamivudine and zidovudine, respectively in anti-HIV drug combination. Copyright © 2018 Elsevier B.V. All rights reserved.

A reporter model to visualize imprinting stability at the Dlk1 locus during mouse development and in pluripotent cells.

PubMed

Swanzey, Emily; Stadtfeld, Matthias

2016-11-15

Genomic imprinting results in the monoallelic expression of genes that encode important regulators of growth and proliferation. Dysregulation of imprinted genes, such as those within the Dlk1-Dio3 locus, is associated with developmental syndromes and specific diseases. Our ability to interrogate causes of imprinting instability has been hindered by the absence of suitable model systems. Here, we describe a Dlk1 knock-in reporter mouse that enables single-cell visualization of allele-specific expression and prospective isolation of cells, simultaneously. We show that this 'imprinting reporter mouse' can be used to detect tissue-specific Dlk1 expression patterns in developing embryos. We also apply this system to pluripotent cell culture and demonstrate that it faithfully indicates DNA methylation changes induced upon cellular reprogramming. Finally, the reporter system reveals the role of elevated oxygen levels in eroding imprinted Dlk1 expression during prolonged culture and in vitro differentiation. The possibility to study allele-specific expression in different contexts makes our reporter system a useful tool to dissect the regulation of genomic imprinting in normal development and disease. © 2016. Published by The Company of Biologists Ltd.

Synthesis of caffeic acid molecularly imprinted polymer microspheres and high-performance liquid chromatography evaluation of their sorption properties.

PubMed

Valero-Navarro, Angel; Gómez-Romero, María; Fernández-Sánchez, Jorge F; Cormack, Peter A G; Segura-Carretero, Antonio; Fernández-Gutiérrez, Alberto

2011-10-14

In the current work, a molecularly imprinted polymer (MIP) has been synthesised and used to enable the extraction of a naturally-occurring antioxidant from complex media. More specifically, we describe the first example of a caffeic acid (CA) MIP which has been synthesised in the form of well-defined polymer microspheres, and its use for the extraction of CA from fruit juice sample. The CA MIP was synthesised by precipitation polymerisation using 4-vinylpyridine as functional monomer, divinylbenzene-80 as crosslinker and acetonitrile:toluene (75/25, v/v) as porogen. The particle sizing and morphological characterisation of the polymers was carried out by means of scanning electron microscopy (narrow particle size distribution; ∼5 and 1.5 μm particle diameters for the MIP and NIP [non-imprinted polymer], respectively) and nitrogen sorption porosimetry (specific surface areas of 340 and 350 m(2)g(-1), and specific pore volumes of 0.17 and 0.19 cm(3)g(-1) for the MIP and NIP, respectively). The polymers were evaluated further by batch rebinding experiments, and from the derived isotherms their binding capacity and binding strength were determined (number of binding sites (N(K))=0.6 and 0.3 mmol g(-1) for the MIP and NIP, respectively, and apparent average adsorption constant (K(N))=10.0 and 1.6L mmol(-1) for the MIP and NIP, respectively). To evaluate the molecular recognition character of the MIP it was packed into a stainless steel column (50 mm × 4.6 mm i.d.) and evaluated as an HPLC-stationary phase. The mobile phase composition, flow rate, and the elution profile were then optimised in order to improve the peak shape without negatively affecting the imprinting factor (IF). Very interesting, promising properties were revealed. The imprinting factor (IF) under the optimised conditions was 11.9. Finally, when the imprinted LC column was used for the selective recognition of CA over eight related compounds, very good selectivity was obtained. This outcome enabled the direct extraction of CA in commercial apple juice samples with recoveries in excess of 81% and, rather significantly, without any need for a clean-up step prior to the extraction. Copyright © 2011 Elsevier B.V. All rights reserved.

Molecularly imprinted phloroglucinol-formaldehyde-melamine resin prepared in a deep eutectic solvent for selective recognition of clorprenaline and bambuterol in urine.

PubMed

Liang, Shiru; Yan, Hongyuan; Cao, Jiankun; Han, Yehong; Shen, Shigang; Bai, Ligai

2017-01-25

A new molecularly imprinted phloroglucinol-formaldehyde-melamine resin (MIPFMR) was synthesized in a deep eutectic solvent (DES) using phenylephrine as a dummy template. The MIPFMR was used as a solid phase extraction (SPE) sorbent for the selective isolation and recognition of clorprenaline (CLP) and bambuterol (BAM) in urine. Phloroglucinol and melamine were used as double functional monomers that introduced abundant hydrophilic groups (such as hydroxyl groups, imino groups, and ether linkages) into the MIPFMR, making it compatible with aqueous solvents. In addition, the formation of DES by combining the quaternary ammonium salt of choline chloride with ethylene glycol as a hydrogen bond donor was an environmentally safe alternative to toxic organic solvents such as chloroform and dimethylsulfoxide that are typically used in the preparation of most molecularly imprinted polymers (MIPs). Moreover, MIPFMR-based SPE of CLP and BAM in urine resulted in higher recoveries and purer extracts than those obtained by using other SPE materials (e.g., SCX, C 18 , HLB, and non-imprinted phloroglucinol-formaldehyde-melamine resin (NIPFMR)). The optimized MIPFMR-SPE-HPLC-UV method had good linearity (r 2  ≥ 0.9996) ranging from 15.0 to 3000.0 ng mL -1 for CLP and BAM, and the recoveries at three spiked levels ranged from 91.7% to 100.1% with RSDs ≤7.6%. The novel MIPFMR-SPE-HPLC-UV method is simple, selective, and accurate, and can be used for the determination of CLP and BAM in urine samples. Copyright © 2016 Elsevier B.V. All rights reserved.

Microcontact imprinted quartz crystal microbalance nanosensor for protein C recognition.

PubMed

Bakhshpour, Monireh; Özgür, Erdoğan; Bereli, Nilay; Denizli, Adil

2017-03-01

Detection of protein C (PC) in human serum was performed by quartz crystal microbalance (QCM) based on molecular imprinting technique (MIP). The high-resolution and mass-sensitive QCM based sensor was integrated with high sensitivity and selectivity of the MIP technique. The PC microcontact imprinted (PC-μCIP) nanofilm was prepared on the glass surface. Then, the PC-μCIP/QCM sensor was prepared with 2-hydroxyethyl methacrylate (HEMA), ethylene glycol dimethacrylate (EGDMA) and N-methacryloyl l-histidine methylester (MAH) as the functional monomer with copper(II) ions. The polymerization was performed under UV light (100W and 365nm) for 20-25min under nitrogen atmosphere. The characterization studies of QCM sensor were done by observation using atomic force microscopy (AFM), contact angle measurements, ellipsometry and fourier transform infrared spectroscopy (FTIR). Detection of PC was investigated in a concentration range of 0.1-30μg/mL. Selectivity of PC-μCIP and PC non-imprinted/QCM (PC-non-μCIP) sensors for PC determination was investigated by using proteins namely hemoglobin (Hb), human serum albumin (HSA) and fibrinogen solutions. QCM sensor was also used for detection of PC molecules in aqueous solutions and human plasma. The detection limit was determined as 0.01μg/mL for PC analysis. The PC-μCIP/QCM sensor was used for five consecutive adsorption-desorption cycles. According to the results, the PC-μCIP/QCM sensor had obtained high selectivity and sensitivity for detection of PC molecules. Copyright © 2016 Elsevier B.V. All rights reserved.

Mechanisms of activation of the paternally expressed genes by the Prader-Willi imprinting center in the Prader-Willi/Angelman syndromes domains

PubMed Central

Rabinovitz, Shiri; Kaufman, Yotam; Ludwig, Guy; Razin, Aharon; Shemer, Ruth

2012-01-01

The Prader-Willi syndrome/Angelman syndrome (PWS/AS) imprinted domain is regulated by a bipartite imprinting control center (IC) composed of a sequence around the SNRPN promoter (PWS-IC) and a 880-bp sequence located 35 kb upstream (AS-IC). The AS-IC imprint is established during gametogenesis and confers repression upon PWS-IC on the maternal allele. Mutation at PWS-IC on the paternal allele leads to gene silencing across the entire PWS/AS domain. This silencing implies that PWS-IC functions on the paternal allele as a bidirectional activator. Here we examine the mechanism by which PWS-IC activates the paternally expressed genes (PEGs) using transgenes that include the PWS-IC sequence in the presence or absence of AS-IC and NDN, an upstream PEG, as an experimental model. We demonstrate that PWS-IC is in fact an activator of NDN. This activation requires an unmethylated PWS-IC in the gametes and during early embryogenesis. PWS-IC is dispensable later in development. Interestingly, a similar activation of a nonimprinted gene (APOA1) was observed, implying that PWS-IC is a universal activator. To decipher the mechanism by which PWS-IC confers activation of remote genes, we performed methylated DNA immunoprecipitation (MeDIP) array analysis on lymphoblast cell lines that revealed dispersed, rather than continued differential methylation. However, chromatin conformation capture (3c) experiments revealed a physical interaction between PWS-IC and the PEGs, suggesting that activation of PEGs may require their proximity to PWS-IC. PMID:22529396

Preparation of a surface-grafted imprinted ceramic membrane for selective separation of molybdate anion from water solutions.

PubMed

Zeng, Jianxian; Dong, Zhihui; Zhang, Zhe; Liu, Yuan

2017-07-05

A surface-grafted imprinted ceramic membrane (IIP-PVI/CM) for recognizing molybdate (Mo(VI)) anion was prepared by surface-initiated graft-polymerization. Firstly, raw alumina ceramic membrane (CM) was deposited with SiO 2 active layer by situ hydrolysis deposition method. Subsequently, γ-methacryloxy propyl trimethoxyl silane (MPS) was used as a coupling agent to introduce double bonds onto the SiO 2 layer (MPS-CM). Then, 1-vinylimidazole (VI) was employed as a functional monomer to graft-polymerization onto the MPS-CM (PVI-CM). During the graft-polymerization, the influence factors of grafting degree of PVI were investigated in detail. Under optimum conditions (monomer concentration 20wt%, temperature 70°C, initiator amount 1.1wt% and reaction time 8h), the grafting degree of 20.39g/100g was obtained. Further, Mo(VI) anion was used as a template to imprint in the PVI-CM by employing 1,6-dibromohexane as a cross-linking agent, and then Mo(VI) was removed, obtaining the IIP-PVI/CM with many imprinted cavities for Mo(VI). Thereafter, static adsorption and dynamic separation properties of IIP-PVI/CM for Mo(VI) were studied. Results indicate that IIP-PVI/CM shows a specific selectivity for Mo(VI) with the adsorption capacity of 0.69mmol/100g, and the selectivity coefficient of IIP-PVI/CM is 7.48 for molybdate to tungstate anions. During the dynamic separation, IIP-PVI/CM has also good selectivity for separation of Mo(VI) and W(VI) anions. Copyright © 2017 Elsevier B.V. All rights reserved.

76 FR 30542 - Adult Signature Services

Federal Register 2010, 2011, 2012, 2013, 2014

2011-05-26

...[supreg]. USPS[supreg]-approved PC Postage[supreg] (registered end- users only). Permit imprint, if the.... Permit imprint, if the customer electronically submits postage statements and mailing documentation. d... mailpieces (not bearing a permit imprint) with Adult Signature at a Post Office lobby drop, collection box...

Mycotoxin analysis using imprinted materials technology: Recent developments

USDA-ARS?s Scientific Manuscript database

Molecular imprinting technology is an attractive, cost effective, and robust alternative to address the limitations of highly selective natural receptors, such as antibodies and aptamers. The field of molecular imprinting has seen a recent surge in growth with several commercially available products...

Preliminary evidence of a neurophysiological basis for individual discrimination in filial imprinting.

PubMed

Town, Stephen Michael

2011-12-01

Filial imprinting involves a predisposition for biologically important stimuli and a learning process directing preferences towards a particular stimulus. Learning underlies discrimination between imprinted and unfamiliar individuals and depends upon the IMM (intermediate and medial mesopallium). Here, IMM neurons responded differentially to familiar and unfamiliar conspecifics following socialization and the neurophysiological effects of social experience differed between hemispheres. Such findings may provide a neurophysiological basis for individual discrimination in imprinting. Copyright © 2011 Elsevier B.V. All rights reserved.

Quantification of the memory imprint effect for a charged particle environment

NASA Technical Reports Server (NTRS)

Bhuva, B. L.; Johnson, R. L., Jr.; Gyurcsik, R. S.; Kerns, S. E.; Fernald, K. W.

1987-01-01

The effects of total accumulated dose on the single-event vulnerability of NMOS resistive-load SRAMs are investigated. The bias-dependent shifts in device parameters can imprint the memory state present during exposure or erase the imprinted state. Analysis of these effects is presented along with an analytic model developed for the quantification of these effects. The results indicate that the imprint effect is dominated by the difference in the threshold voltage of the n-channel devices.

Molecular biology. Mothers setting boundaries.

PubMed

Thorvaldsen, J L; Bartolomei, M S

2000-06-23

Certain genes are only expressed at one allele, a phenomenon called imprinting. Although it is well established that one allele of certain imprinted genes is silenced through methylation, this does not appear to be the case for all imprinted genes. In a thoughtful Perspective, Thorvaldsen and Bartolomei discuss new findings showing that insertion of insulator elements (boundary regions) between the promoter of a gene and its enhancer (a sequence that boosts gene expression) may be another way in which genes are silenced during imprinting.

Clinical features associated with copy number variations of the 14q32 imprinted gene cluster.

PubMed

Rosenfeld, Jill A; Fox, Joyce E; Descartes, Maria; Brewer, Fallon; Stroud, Tracy; Gorski, Jerome L; Upton, Sheila J; Moeschler, John B; Monteleone, Berrin; Neill, Nicholas J; Lamb, Allen N; Ballif, Blake C; Shaffer, Lisa G; Ravnan, J Britt

2015-02-01

Uniparental disomy (UPD) for imprinted chromosomes can cause abnormal phenotypes due to absent or overexpression of imprinted genes. UPD(14)pat causes a unique constellation of features including thoracic skeletal anomalies, polyhydramnios, placentomegaly, and limited survival; its hypothesized cause is overexpression of paternally expressed RTL1, due to absent regulatory effects of maternally expressed RTL1as. UPD(14)mat causes a milder condition with hypotonia, growth failure, and precocious puberty; its hypothesized cause is absence of paternally expressed DLK1. To more clearly establish how gains and losses of imprinted genes can cause disease, we report six individuals with copy number variations of the imprinted 14q32 region identified through clinical microarray-based comparative genomic hybridization. Three individuals presented with UPD(14)mat-like phenotypes (Temple syndrome) and had apparently de novo deletions spanning the imprinted region, including DLK1. One of these deletions was shown to be on the paternal chromosome. Two individuals with UPD(14)pat-like phenotypes had 122-154kb deletions on their maternal chromosomes that included RTL1as but not the differentially methylated regions that regulate imprinted gene expression, providing further support for RTL1 overexpression as a cause for the UPD(14)pat phenotype. The sixth individual is tetrasomic for a 1.7Mb segment, including the imprinted region, and presents with intellectual disability and seizures but lacks significant phenotypic overlap with either UPD(14) syndrome. Therefore, the 14q32 imprinted region is dosage sensitive, with deletions of different critical regions causing UPD(14)mat- and UPD(14)pat-like phenotypes, while copy gains are likely insufficient to recapitulate these phenotypes.

Genome-wide methylation analysis in Silver-Russell syndrome patients

PubMed Central

Böhm, S; Frost, JM; Puszyk, W; Abu-Amero, S; Stanier, P; Schulz, R; Moore, GE; Oakey, RJ

2015-01-01

Silver-Russell Syndrome (SRS) is a clinically heterogeneous disorder characterised by severe in utero growth restriction and poor postnatal growth, body asymmetry, irregular craniofacial features and several additional minor malformations. The aetiology of SRS is complex and current evidence strongly implicates imprinted genes. Approximately half of all patients exhibit DNA hypomethylation at the H19/IGF2 imprinted domain, and around 10% have maternal uniparental disomy of chromosome 7. We measured DNA methylation in 18 SRS patients at >485,000 CpG sites using DNA methylation microarrays. Using a novel bioinformatics methodology specifically designed to identify subsets of patients with a shared epimutation, we analysed methylation changes genome-wide as well as at known imprinted regions to identify SRS-associated epimutations. Our analysis identifies epimutations at the previously characterised domains of H19/IGF2 and at imprinted regions on chromosome 7, providing proof of principle that our methodology can detect DNA methylation changes at imprinted loci. In addition we discovered two novel epimutations associated with SRS and located at imprinted loci previously linked to relevant mouse and human phenotypes. We identify RB1 as an additional imprinted locus associated with SRS, with a region near the RB1 DMR hypermethylated in 13/18 (~70 %) patients. We also report 6/18 (~33 %) patients were hypermethylated at a CpG island near the ANKRD11 gene. We do not observe consistent cooccurrence of epimutations at multiple imprinted loci in single SRS individuals. SRS is clinically heterogeneous and the absence of multiple imprinted loci epimutations reflects the heterogeneity at the molecular level. Further stratification of SRS patients by molecular phenotypes might aid the identification of disease causes. PMID:25563730

Examination of Global Methylation and Targeted Imprinted Genes in Prader-Willi Syndrome.

PubMed

Manzardo, A M; Butler, M G

2016-01-01

Methylation changes observed in Prader-Willi syndrome (PWS) may impact global methylation as well as regional methylation status of imprinted genes on chromosome 15 (in cis) or other imprinted obesity-related genes on other chromosomes (in trans) leading to differential effects on gene expression impacting obesity phenotype unique to (PWS). Characterize the global methylation profiles and methylation status for select imprinted genes associated with obesity phenotype in a well-characterized imprinted, obesity-related syndrome (PWS) relative to a cohort of obese and non-obese individuals. Global methylation was assayed using two methodologies: 1) enriched LINE-1 repeat sequences by EpigenDx and 2) ELISA-based immunoassay method sensitive to genomic 5-methylcytosine by Epigentek. Target gene methylation patterns at selected candidate obesity gene loci were determined using methylation-specific PCR. Study participants were recruited as part of an ongoing research program on obesity-related genomics and Prader-Willi syndrome. Individuals with non-syndromic obesity (N=26), leanness (N=26) and PWS (N=39). A detailed characterization of the imprinting status of select target genes within the critical PWS 15q11-q13 genomic region showed enhanced cis but not trans methylation of imprinted genes. No significant differences in global methylation were found between non-syndromic obese, PWS or non-obese controls. None. Percentage methylation and the methylation index. The methylation abnormality in PWS due to errors of genomic imprinting effects both upstream and downstream effectors in the 15q11-q13 region showing enhanced cis but not trans methylation of imprinted genes. Obesity in our subject cohorts did not appear to impact global methylation levels using the described methodology.

Examination of Global Methylation and Targeted Imprinted Genes in Prader-Willi Syndrome

PubMed Central

Manzardo, AM; Butler, MG

2016-01-01

Context Methylation changes observed in Prader-Willi syndrome (PWS) may impact global methylation as well as regional methylation status of imprinted genes on chromosome 15 (in cis) or other imprinted obesity-related genes on other chromosomes (in trans) leading to differential effects on gene expression impacting obesity phenotype unique to (PWS). Objective Characterize the global methylation profiles and methylation status for select imprinted genes associated with obesity phenotype in a well-characterized imprinted, obesity-related syndrome (PWS) relative to a cohort of obese and non-obese individuals. Design Global methylation was assayed using two methodologies: 1) enriched LINE-1 repeat sequences by EpigenDx and 2) ELISA-based immunoassay method sensitive to genomic 5-methylcytosine by Epigentek. Target gene methylation patterns at selected candidate obesity gene loci were determined using methylation-specific PCR. Setting Study participants were recruited as part of an ongoing research program on obesity-related genomics and Prader-Willi syndrome. Participants Individuals with non-syndromic obesity (N=26), leanness (N=26) and PWS (N=39). Results A detailed characterization of the imprinting status of select target genes within the critical PWS 15q11-q13 genomic region showed enhanced cis but not trans methylation of imprinted genes. No significant differences in global methylation were found between non-syndromic obese, PWS or non-obese controls. Intervention None. Main outcome measures Percentage methylation and the methylation index. Conclusion The methylation abnormality in PWS due to errors of genomic imprinting effects both upstream and downstream effectors in the 15q11-q13 region showing enhanced cis but not trans methylation of imprinted genes. Obesity in our subject cohorts did not appear to impact global methylation levels using the described methodology. PMID:28111641

Population-genetic models of sex-limited genomic imprinting.

PubMed

Kelly, S Thomas; Spencer, Hamish G

2017-06-01

Genomic imprinting is a form of epigenetic modification involving parent-of-origin-dependent gene expression, usually the inactivation of one gene copy in some tissues, at least, for some part of the diploid life cycle. Occurring at a number of loci in mammals and flowering plants, this mode of non-Mendelian expression can be viewed more generally as parentally-specific differential gene expression. The effects of natural selection on genetic variation at imprinted loci have previously been examined in a several population-genetic models. Here we expand the existing one-locus, two-allele population-genetic models of viability selection with genomic imprinting to include sex-limited imprinting, i.e., imprinted expression occurring only in one sex, and differential viability between the sexes. We first consider models of complete inactivation of either parental allele and these models are subsequently generalized to incorporate differential expression. Stable polymorphic equilibrium was possible without heterozygote advantage as observed in some prior models of imprinting in both sexes. In contrast to these latter models, in the sex-limited case it was critical whether the paternally inherited or maternally inherited allele was inactivated. The parental origin of inactivated alleles had a different impact on how the population responded to the different selection pressures between the sexes. Under the same fitness parameters, imprinting in the other sex altered the number of possible equilibrium states and their stability. When the parental origin of imprinted alleles and the sex in which they are inactive differ, an allele cannot be inactivated in consecutive generations. The system dynamics became more complex with more equilibrium points emerging. Our results show that selection can interact with epigenetic factors to maintain genetic variation in previously unanticipated ways. Copyright © 2017 Elsevier Inc. All rights reserved.