Synchronized Temporal-spatial Analysis via Microscopy and Phoshoproteomics (STAMP) of Quiescence.

Tightly coordinated cell cycle regulation is essential for homeostasis. G 0 , or quiescence, is especially crucial for cells to respond to extracellular stimuli. Little is known about the mechanisms that establish the G 0 program, though the primary cilium (a key signaling hub formed only in G 0 ) is the most widely recognized marker. The study of ciliogenesis is challenging due to its small size, relative to the cell body. To address this gap in our understanding, we developed STAMP (Spatio-Temporal Analysis via Microscopy and Proteomics) to temporally map the changes in cellular landscape occurring in G 0 and ciliogenesis. Using synchronized RPE cells, we used fixed and live cell imaging combined with phosphoproteomics to uncover new signals and order them in these processes, which also allows further, more targeted, analyses (e.g., using genetic and pharmacological perturbations). We propose that STAMP is broadly applicable for studying temporal-spatial signaling processes and the underlying mechanisms in various biological contexts and cell types.

Selective adsorption of 2,4-dinitrophenol on molecularly imprinted nanocomposites of mesoporous silica SBA-15/polyaniline.

Surface imprinting and adoption of a nano-sized physical form are two effective approaches to overcome the template transfer difficulty within molecularly imprinted polymers (MIPs). This work is an attempt to conquer the problem of template transfer difficulty within MIPs by using a nano-reactor as a substrate for the reaction between the monomer and the template. Negatively charged hexagonal nano-channels of SBA-15 can act as a support for attachment of positively charged aniline monomers and the 2,4-dinitrophenol (2,4-DNP) template. The imprinted and non-imprinted SBA-15/polyaniline nanocomposites were characterized by Fourier transform infrared (FT-IR), transmission electron microscopy (TEM), scanning electron microscopy (SEM) and nitrogen adsorption-desorption isotherms. The results showed that the synthesized polymer possessed a highly ordered mesoporous structure. The distribution coefficient values of 2,4-DNP, K(d (2,4-DNP)), were estimated as 301.4 ± 2.3 and 101.2 ± 1.0 mL g(-1) for imprinted and non-imprinted polymers (NIP), respectively. The MIP-solid-phase extraction (SPE) process was optimized by evaluating the type of washing solvent and the composition and volume of the eluting solvent. The prepared MIP was used as a selective sorbent for SPE of 2,4-DNP in the presence of phenolic compounds in tap and sea water. The experimental results indicated that the MIP-SPE and NIP-SPE column yielded recoveries higher than 96% and 38%, respectively. The R.S.D. values were also lower than 3.2% and 4.6% for MIP-SPE and NIP-SPE, respectively.

Murine xenograft bioreactors for human immunopeptidome discovery.

The study of peptides presented by MHC class I and class II molecules is limited by the need for relatively large cell numbers, especially when studying post-translationally modified or otherwise rare peptide species. To overcome this problem, we pose the hypothesis that human cells grown as xenografts in immunodeficient mice should produce equivalent immunopeptidomes as cultured cells. Comparing human cell lines grown either in vitro or as murine xenografts, we show that the immunopeptidome is substantially preserved. Numerous features are shared across both sample types, including peptides and proteins featured, length distributions, and HLA-binding motifs. Peptides well-represented in both groups were from more abundant proteins, or those with stronger predicted HLA binding affinities. Samples grown in vivo also recapitulated a similar phospho-immunopeptidome, with common sequences being those found at high copy number on the cell surface. These data indicate that xenografts are indeed a viable methodology for the production of cells for immunopeptidomic discovery.

Electrochemically prepared solid-phase microextraction coatings--a review.

During the last decade, electrochemically prepared coatings have gained widespread acceptance for solid-phase microextraction (SPME) applications. The current review classified these coatings as electropolymerized conductive polymers (CPs), electrodeposited metal oxides, electrophoretically deposited carbon nanotubes (CNTs) and anodized metals. These electrochemical methods resulted in easily controlled and reproducible SPME coatings with inherent characteristics such as biocompatibility, thermal stability and porous structure. The objective of this review is to provide a concise overview of recent developments in the electrochemically prepared SPME coatings and their analytical applications.

Design and synthesis of molecularly imprinted polypyrrole based on nanoreactor SBA-15 for recognition of ascorbic acid.

Molecular imprinting is an attractive technique for preparing mimics of natural and biological receptors. Nevertheless, molecular imprinting for aqueous systems remains a challenge due to the hydrogen bonding between templates and functional monomers destroyed in the bulk water. The hydrogen bonding between templates and monomers are the most crucial factor governing recognition, particularly in non-covalent molecularly imprinted polymers. Using mesoporous materials for molecular imprinting is an effective approach to overcome this barrier and to remove the limitations of the traditional molecularly imprinted polymers which include incomplete template removal, small binding capacity, slow mass transfer, and irregular materials shape. Here, SBA-15 was used as a mesoporous silica material for synthesis of molecularly imprinted polypyrrole. The pyrrole monomers and template molecules were immobilized onto the SBA-15 hexagonal channels, and then polymerization occurred. The resulting nanocomposites were characterized by Fourier transform infrared (FT-IR) analysis, scanning electron microscopy (SEM) and transmission electron microscopy (TEM) methods. In batch rebinding tests, the imprinted nanocomposites reached saturated adsorption within 100min and exhibited significant specific recognition toward the ascorbic acid (AA) with high adsorption capacity (83.7mg g(-1)). To further illustrate the recognition property of the imprinted nanocomposites, binary competitive and non-competitive adsorption experiments were performed with ascorbic acid, dopamine, paracetamol and epinephrine. The imprinting factors for these compounds in non-competitive adsorption experiments were 3.2, 1.5, 1.4 and 1.3, respectively. The results showed that the imprinted nanocomposites exhibited significant adsorption selectivity for the ascorbic acid against the related compounds.

Magnetic molecularly imprinted nanoparticles based on grafting polymerization for selective detection of 4-nitrophenol in aqueous samples.

In this study, an analytical procedure for the selective extraction and detection of 4-nitrophenol (4-NP) was investigated by using of molecularly imprinted polymer on the surface of magnetic nanoparticles (MNPs). The magnetic nanoparticles were modified by tetraethyl orthosilicate (TEOS) and 3-methacryloxypropyl trimethoxysilane (MPTS) before imprinting. The magnetic molecularly imprinted polymer (MMIP) was polymerized at the surface of modified MNPs by using of methacrylic acid (MAA) as functional monomer, 4-NP as template and ethylene glycol dimethacrylate (EGDMA) as cross-linker. Experimental design by the Taguchi method was used for the optimization of synthesis procedure of imprinted polymer. The resulting MMIP showed high adsorption capacity, proper selectivity and fast kinetic binding for the template molecule. It was characterized by Fourier transform infrared (FT-IR) analysis, scanning electron microscopy (SEM) and transmission electron microscopy (TEM) methods. The maximum adsorption capacity of MMIP was obtained as 57.8mgg(-1) and it took about 2h to achieve the equilibrium state. The adsorption curve of MMIP was also fitted with the Freundlich isotherm equation. The assay exhibited a linear range of 25-1000µgL(-1) for 4-NP with the correlation coefficient (R(2)) of 0.995. The method was also examined for the analysis of 4-NPs in seawater. For recovery evaluation, the seawater samples were spiked at two concentration levels of 50 and 100µgL(-1) of 4-NPs and the recovery values were in the range of 79.3-99.8%. The relative standard deviations (RSD) for the recoveries were less than 5.2%.