Imprinting at the KBTBD6 locus involves species-specific m ternal methylation and monoallelic expression in livestock animals

Background The primary differentially methylated regions(DMRs) which are maternally hypermethylated serve as imprinting control regions(ICRs) that drive monoallelic gene expression, and these ICRs have been investigated due to their implications in mammalian development. Although a subset of genes has been identified as imprinted, in-depth comparative approach needs to be developed for identification of species-specific imprinted genes. Here, we examined DNA methylation status and allelic expression at the KBTBD6 locus across species and tissues and explored potential mechanisms of imprinting.Results Using whole-genome bisulfite sequencing and RNA-sequencing on parthenogenetic and normal porcine embryos, we identified a maternally hypermethylated DMR between the embryos at the KBTBD6 promoter Cp G island and paternal monoallelic expression of KBTBD6. Also, in analyzed domesticated mammals but not in humans, non-human primates and mice, the KBTBD6 promoter Cp G islands were methylated in oocytes and/or allelically methyl-ated in tissues, and monoallelic KBTBD6 expression was observed, indicating livestock-specific imprinting. Further analysis revealed that these Cp G islands were embedded within transcripts in porcine and bovine oocytes which coexisted with an active transcription mark and DNA methylation, implying the presence of transcription-dependent imprinting.Conclusions In this study, our comparative approach revealed an imprinted expression of the KBTBD6 gene in domesticated mammals, but not in humans, non-human primates, and mice which implicates species-specific evolution of genomic imprinting.

Ionically Imprinting-Based Copper(Ⅱ)Label-Free Detection for Preventing Hearing Loss

Copper is a microelement with important physiological functions in the body.However,the excess copper ion(Cu^(2+))may cause severe health problems,such as hair cell apoptosis and the resultant hearing loss.Therefore,the assay of Cu^(2+)is important.We integrate ionic imprinting technology(IIT)and structurally colored hydrogel beads to prepare chitosan-based ionically imprinted hydrogel beads(IIHBs)as a low-cost and high-specificity platform for Cu^(2+)detection.The IIHBs have a macroporous microstructure,uniform size,vivid structural color,and magnetic responsiveness.When incubated in solution,IIHBs recognize Cu^(2+)and exhibit a reflective peak change,thereby achieving label-free detection.In addition,benefiting from the IIT,the IIHBs display good specificity and selectivity and have an imprinting factor of 19.14 at 100μmol·L^(-1).These features indicated that the developed IIHBs are promising candidates for Cu^(2+)detection,particularly for the prevention of hearing loss.

Plant Genomic Imprinting and Its Effect on Seed Development

Genomic imprinting is the epigenetic phenomenon by which certain genes are expressed in a parent-of-origin-specific manner, and was first discovered in mammalian embryos. Recent studies have shown that it also occurs in developing plant seeds, and is now becoming a hot topic of biology of plant seed development. According to the previous studies on imprinted genes, imprinting mechanism and their roles in plant seed development, the current progress of genomic imprinting in plant seed development was summarized and possible strategies were proposed to deal with the problems, which could provide helpful information for further research.

Maternal imprinting of the neonatal microbiota colonization in intrauterine growth restricted piglets:a review

Early colonization of intestinal microbiota during the neonatal stage plays an important role on the development of intestinal immune system and nutrients absorption of the host.Compared to the normal birth weight(NBW)piglets,intrauterine growth restricted(IUGR)piglets have a different intestinal microbiota during their early life,which is related to maternal imprinting on intestinal microbial succession during gestation,at birth and via suckling.Imbalanced allocation of limited nutrients among fetuses during gestation could be one of the main causes for impaired intestinal development and microbiota colonization in neonatal IUGR piglets.In this review,we summarized the potential impact of maternal imprinting on the colonization of the intestinal microbiota in IUGR piglets,including maternal undernutrition,imbalanced allocation of nutrients among fetuses,as well as vertical microbial transmission from mother to offspring during gestation and lactation.At the same time,we give information about the current maternal nutritional strategies(mainly breastfeeding,probiotics and prebiotics)to help colonization of the advantageous intestinal microbiota for IUGR piglets.

Genome-wide identification of imprinted genes in pigs and their different imprinting status compared with other mammals

DEAR EDITOR,Genomic imprinting often results in parent-of-origin specific differential expression of maternally and paternally inherited alleles and plays an essential role in mammalian development and growth.Mammalian genomic imprinting has primarily been studied in mice and humans,with only limited information available for pigs.To systematically characterize this phenomenon and evaluate imprinting status between different species,we investigated imprinted genes on a genome-wide scale in pig brain tissues.

Characterization of the imprinting and expression patterns of ZAG2 in maize endosperm and embryo

ZAG2 has been identified as a maternally expressed imprinted gene in maize endosperm.Our study revealed that paternally inherited ZAG2 alleles were imprinted in maize endosperm and embryo at 14 days after pollination(DAP), and consistently imprinted in endosperm at 10, 12, 16, 18, 20, 22, 24, 26, and 28 DAP in reciprocal crosses between B73 and Mo17. ZAG2 alleles were also imprinted in reciprocal crosses between Zheng 58 and Chang7-2 and between Huang C and 178. ZAG2 alleles exhibited differential imprinting in hybrids of 178 × Huang C and B73 × Mo17, while in other hybrids ZAG2 alleles exhibited binary imprinting. The tissue-specific expression pattern of ZAG2 showed that ZAG2 was expressed at a high level in immature ears, suggesting that ZAG2 plays important roles in not only kernel but ear development.

Enantiomeric Resolution on L-Carnitine Selective Polymers Prepared by Molecular Imprinting

L-carnitine selective polymers were prepared by molecular imprinting using methacrylic acid as the functional monomer. The acid function of the monomer is expected to form hydrogen bond and ionic interactions with the amine function of the target molecule L-carnitine. The imprinted polymers were used as stationary phases in high-performance liquid chromatography (HPLC). It was shown that L-carnitine imprinted polymer exhibited a higher affinity to its template molecule, while the non-imprinted polymer had no affinity to the compounds tested. Racemic carnitine hydrochloride was efficiently resolved on the L-carnitine imprinted polymer, and the separation factor is 1.9.

Genomic Imprinting—The Story of the Other Half and the Conflicts of Silencing

G-enomic imprinting is an epigenetic mechanism that produces functional differences between the paternal and mammal genomes and plays an essential role in mammalian development and growth. There are a number of genes in our genomes that are subject to genomic imprinting where one parent＇s copy of the gene is expressed while the other is silent. Silencing of one allele predetermines that any function ascribed to that gene are now dependant on the single active copy. Possession of only a single active allele can lead to deleterious health consequences in humans. If imprinted genes are crucial in mammalian development, one would also expect mutations in these genes to cause diseases. Since imprinting is an epigenetic mechanism, mistakes in maintaining epigenetic mark also cause imprinting disorders. Here we in this review focus on the current understanding of this unique genetic mechanism more than two decades after the first description of the imprinting phenomenon was given by McGrath and Solter. Although the possible molecular mechanisms by which imprinting is imposed and maintained are being identified, we have a long way to go in understanding the molecular mechanisms that regulate the expression of these oddly behaving genes, the function of imprinting and the evolution. Post genomic technologies might ultimately lead to a better understanding of the ＇imprinting effects＇.

Adsorption and degradation of norfloxacin by a novel molecular imprinting magnetic Fenton-like catalyst

In this study,a novel magnetically separable adsorbent,molecular imprinting magnetic γ-Fe_2O_3/crosslinked chitosan composites(MIPs),were prepared by a microemulsion process.Adsorption and Fenton-like oxidative degradation of a model pharmaceutical pollutant norfloxacin(NOR) by using MIPs were investigated.Various characterization methods were used to study the properties of MIPs,and it is suggested that the hydroxyl groups are the main adsorption sites for NOR.MIPs present better selective adsorption for NOR than its reference antibiotic sulfadiazine.The NOR adsorption data can be well fitted by Langmuir isotherm model and pseudosecond-order kinetic model.The optimum pH range for NOR adsorption is 7-10.In addition,the MIP-catalyzed Fenton-like system(MIPs/H_2O_2) exhibits remarkably faster removal rate for NOR than the case of γ-Fe_2O_3/H_2O_2.The result indicates that MIPs will be a good functional material in decontamination of pharmaceutical wastewaters since MIPs can be magnetically recycled after the treatment.

Molecular Imprinting Fibrous Membranes of Poly(acrylonitrile-co-acrylic acid) Prepared by Electrospinning

IntroductionOver the past few decades, molecular imprinting has been described as a technology for preparing ＂molecular doors＂ which can be matched to ＂template keys＂. It has been found to be a simple and effective approach to introduce specific recognition sites into synthetic polymers, namely, to create molecular imprinting polymers Remarkable features such as stability, ease of preparation and low cost, have made molecular imprinting polymers particularly attractive in chemical sensors, catalysis, drug delivery, and dedicated separations. Practical applications of molecular imprinting polymers require accessible sites, fast mass transfer, and quick binding. However, present techniques used to prepare molecular imprinting polymers most often result in materials exhibiting a high affinity and selectivity but a low capacity and poor site accessibility for the target molecules. It is also very difficult to remove the imprinted molecules located in these molecular imprinting polymers because the highly cross-linked structures do not allow the templates to move freely. To some extent, combining molecular imprinting technology with membrane separation and surface imprinting can overcome the shortcomings, such as mass transfer limitations and non-quantitative recovery of the template molecules seen for imprinted materials fabricated by conventional bulk methods. In that ease, it appears to us that molecular imprinting polymers with high surface area to volume ratios are particularly desirable for largescale applications. Eleetrospun nano and ultrafine fibrous membranes are the most suitable materials due to advantages such as： （1） large specific surfaces, providing relatively high imprinting sites per unit mass; （2） fine porous structures, resulting in the accessibility of imprinting sites and low diffusion resistance necessary for high efficiency; and （3） easy recoverability from practical operation or applicability for continuous usages. Therefore, in this work, we prepared a unique kind of imprinted material--molecularly imprinted fibrous membranes of poly （ acrylonitrile-co-acrylic acid） fabricated by means of an electrospinning process.

Polyacrylamide hydrogels with phenylboronic acid moieties for the imprinting of proteins

In this letter,N-acryloyl-3-aminophenylboronic acid（AAPBA） was synthesized and then examined as a new functional monomer for protein imprinting.It was allowed to be copolymerized with acrylamide to produce hemoglobin- or lysozyme-imprinted hydrogels.In template rebinding tests,the imprinted gels showed significant increase in the specific binding with the increase of the AAPBA amounts in the prepolymerization recipes.These results indicate that AAPBA may be a useful functional monomer for its moderate interactions with protein molecules.

Making High Selective Molecule Imprinting Polymer (MIP) In Polar Solvent

Acrylamide was used as functional monomer to make high chiral selective molecule imprinting polymers against N-alpha-protected amino acid in polar solvent. The factor, which influence the efficiency of the polymer and the mechanism of chiral recognition were investigated.

Molecular Imprinting of (R)-(+)-α-Methylbenzylamine for Chiral Stationary Phase

A new type of molecular imprinting stationary phase was prepared by using R- (+)-α -methylbenzy lamine as the print molecule. Experiments of high performance liquid chromatography show that the new stationary phase has high enantio-selectivity and discriminates (R, S) -(± )- α -methylbenzylamine successful ly with α value of 1. 67

Different Imprinting Status of IGF-2 in Epithelial Ov arian Tumors

To explore whether the imprinting status of IGF 2 in the malignant epithelial ovarian tumors is different from that in benign tumors, the target sequences (DNA and RNA) which contain a polymorphism site for ApaI restriction endonuclease digestion were amplified with PCR and RT PCR methods. Then the PCR/RT PCR products were digested by ApaI. The IGF 2 transcriptional pattern came out from the results of endonucleases digestion. Among the 36 cases of benign epithelial ovarian tumors, 20 were heterozygous for ApaI locus and all showed genomic imprinting. While in the malignant group, 22 were heterozygous for ApaI locus but six were found to lose imprinting. Significant differences existed between the two groups ( P <0.05). Loss of imprinting of IGF 2 may serve as a marker for differentiating the malignant ovarian cancers from the benign ones. In a new field of molecular genetics, our research provides an experimental basis for genetic diagnosis and treatment of the ovarian cancers.

Molecular Imprinting Technique and Its Application in Food Industry

As a novel technique, molecular imprinting technique are attracting more and more attention in recent years, due to its specific recognition function to im- printed molecules. This paper firstly introduced this technique from its history, princi- ple, classification and methods, and then reviewed the application in food industry, and presented possible future research orientations.

Computer Simulation and Experimental Investigations of Phenobarbital Molecular Imprinting System

The interaction process between the phenobarbital（PHN） and acrylamide（AM） was studied using the M062X/6-31G（d,p） method. The PHN and AM were used as the template and functional monomer,respectively. The molecular electrostatic potential（MEP） was simulated for predicting the reactive sites. The atoms in molecules theory helped to reveal the imprinting mechanism and optimize the molar ratios for PHN and AM. The molecular imprinted polymers（MIPs） containing PHN were synthesized through the precipitation polymerization. The diameter range of the obtained MIPs was from 150 to 390 nm. According to the computational results,MIPs with the molar ratio of PHN and AM equal to 1：6 showed high selective adsorption for PHN. The apparent maximum adsorption quantity（Q_（max）） of MIPs toward PHN was 7.9 mg/g,and the Qmax of nonimprinted polymer microspheres（NIPs） was 3.2 mg/g. Herein,the studies can provide theoretical and experimental references for the controllable fabrication of MIPs.

Imprinting, methylation, and expression characterization of the maize ETHYLENE-INSENSITIVE 2-like gene

The endosperm plays essential roles in embryogenesis and seed germination and provides abundant resources for human food and industrial products. Identification of genes regulating the development of the endosperm and elucidation of their functions is of great importance for maize genetics and breeding. This study showed that the genespecific imprinted gene, ETHYLENE-INSENSITIVE 2-like(EIN2-like), is maternally expressed in both endosperm and embryo. The maternally expressed pattern was maintained throughout later seed developmental stages. Bisulfite sequencing using DNA obtained from hybrid endosperm tissues showed that the upstream regions of the alleles of EIN2-like were highly methylated at symmetrical sites(CG and CHG). A differentially methylated region in the upstream part of the maternal allele of EIN2-like was identified and found to be hypomethylated. Expression analysis showed that EIN2-like was highly expressed in the maize endosperm as well as at different stages of cell differentiation(8–12 days after pollination) in the hybrid endosperm. These results suggest that the maternally expressed gene EIN2-like may play crucial roles in the regulation of seed development.

Modeling of Microimprinting of Bulk Metallic Glasses

A finite element analysis （FEA） model has been developed to analyze microimprinting of bulk metallic glasses （BMG） near the glass transition temperature （Tg）. The results reveal an approximately universal imprinting response for BMG, independent of surface feature length scale. The scale-independent nature of BMG imprinting derives from the flow characteristics of BMG in the temperature range above Tg. It also shows that the lubrication condition has a mild influence on BMG imprinting in the temperature range above Tg.

Pattern imprinting in deep sub-micron static random access memories induced by total dose irradiation

Pattem imprinting in deep sub-micron static random access memories （SRAMs） during total dose irradiation is inves- tigated in detail. As the dose accumulates, the data pattern of memory cells loading during irradiation is gradually imprinted on their background data pattern. We build a relationship between the memory cell＇s static noise margin （SNM） and the background data, and study the influence of irradiation on the probability density function of ASNM, which is the difference between two data sides＇ SNMs, to discuss the reason for pattern imprinting. Finally, we demonstrate that, for micron and deep sub-micron devices, the mechanism of pattern imprinting is the bias-dependent threshold shift of the transistor, but for a deep sub-micron device the shift results from charge trapping in the shallow trench isolation （STI） oxide rather than from the gate oxide of the micron-device.

Simulation and Preparation of Molecular Imprinting System with Atrazine as Template

In this work, atrazine functions as a template molecule, and trifluoromethacrylic acid （TFMAA）, methacrylic acid （MAA）, methyl methacrylate （MMA）, and acrylamide （AM） serve as functional monomers, respectively. By using density functional theory （DFT）, the computational approach was carried out to simulate the self-assembly system of template and functional monomer. The geometry optimization, action sites, binding energies, and molecular imprinting mechanism of complexes with different functional monomers in different proportions were predicted. The simulation results showed that atrazine and the functional monomers interacted through hydrogen bond. Among the 4 functional monomers, the imprinted complex formed by TFMAA and atrazine with a ratio of （1：6） has the lowest binding energy and the best imprinting effect. Then, the microspheres of molecularly imprinted polymer （MIPs） were prepared by precipitating polymerization using atrazine as the template molecule and TFMAA as the functional monomer. The microspheres were observed by scanning electron microscopy （SEM）. The results showed that atrazine MIP microspheres had average particle size of 400 nm, which was greater than the non-imprinted polymeric microspheres （NIPs）. Dynamic adsorption experiments of MIPs showed that the adsorption reaction reached balance after 200 min. Analysis of the Scatchard plot revealed that the binding sites of MIPs to atrazine were equal class under the studied concentration range. The dissociation constant （Kd） and apparent maximum adsorption quantity （Qmax） of MIPs were 3.6×10^-5 mol/L and 4.83μmol/g, respectively. The study of selective adsorption between atrazine and metribuzin showed that imprinted microspheres had high selectivity for the template molecule atrazine.