A new photolabeling probe for efficient enrichment and deep profiling of cell surface membrane proteome by mass spectrometry

The cell surface membrane proteome is a class of proteins encoded by ~25% of all protein-coding genes in living organisms and plays a key role in mediating communication between the cells and their surrounding environment. However, most cell surface membrane proteins(CSMPs) are naturally expressed at very low levels compared with intracellular proteins. The difficulties in their purification with high specificity further hinder the understanding of their structure and function. In this study, we developed a new photolabeling probe to achieve efficient tagging and facile enrichment of the CSMPs. The probe is composed of a lipid tail for cell surface localization, a polyethylene glycol(PEG) spacer for increased water solubility, two 4-(N-maleimido)benzophenone(MBP) groups for UV-active tagging of the CSMPs, and a biotin tag for subsequent isolation. Application of this photolabeling probe resulted in the successful enrichment and identification of 3098 annotated CSMPs in HT22 cells with close to 70% selectivity. The proposed photolabeling probe and enrichment strategy were demonstrated to be a powerful method for deep cell surface proteome profiling, representing one of the largest groups of current drug targets.

Sutureless amniotic membrane transplantation following excision of ocular surface neoplasia

【正】Dear Sir,S uccess of surgical management of conjunctival neoplasias primarily depends on the complete excision of the mass and eradication of tumor cells from the ocular surface[1-3].Especially in cases that extensive resections are required,primary closure may not be feasible;so ocular surface reconstruction can be a challenging problem for the surgeons.For conjunctival tissue defects different surgical

Severe prelenticular membrane formation on the surface of a hydrophilic acrylic intraocular lens after cataract surgery in an eye with an Ahmed valve implant

【正】Dear Sir,Iam Yong-Sun Ahn,from the Department of Ophthalmology of St.Vincent Hospital of Suwon,Kyungki-do,South Korea.Cataracts are a common problem in eyes with a glaucoma drainage device(GDD),because tube shunt surgery increases the incidence and progression of cataracts[1].An Ahmed valve,the most commonly inserted GDD,is composed of a silicone tube connected to a flat plate sewn to the sclera,and aqueous humor flows from the

Amniotic membrane transplantation with topical interferon alfa-2b after excision of ocular surface squamous neoplasia

To evaluate the outcome of amniotic membrane transplantation（AMT） after tumor excision followed by topical interferon alfa-2 b（IFNα2 b） drops for primary ocular surface squamous neoplasia（OSSN）. Twelve eyes of 12 patients with a mean age of 66±10 y were included. The average followup was 23±10 mo. All 12 patients had limbal involvement. Smooth ocular surface and transparent cornea were achieved in all cases. No sign of inflammation, neovascularization, symblepharon or recurrence was noted at the last follow-up. We conclude that AMT with topical IFNα2 b drops restores a healthy ocular surface in OSSN without recurrence.

THE SURFACE STATE OF MACROPHAGE MEMBRANE UNDER THE ACTION OF Ca^(2+) AND Con A.

The effects of Ca2+ and Con A on the membrane surface of macrophage were studied by STM. Higher peaks correspond to the membrane proteins which were aggregated. Some band-like and lower furrows were expressed in the domain of membrane lipids.

Innovative hydrophobic/hydrophilic perfluoropolyether(PFPE)/polyvinylidene fluoride(PVDF)composite membrane for vacuum membrane distillation

Though membrane distillation(MD)has gained more and more attention in the field of desalination,the wetting phenomenon was still a non-negligible problem.In this work,a method combined dip-coating and UV in situ polymerization for preparing hydrophobic/hydrophilic perfluoropolyether(PFPE)/polyvinylidene fluoride composite membranes.This composite membrane consisted of a top thin hydrophobic coating layer and hydrophilic substrate membrane.In terms of anti-wetting properties,contact angle and liquid entry pressure of all composite membranes(except for those based on 0.45μm)exceeded 160°and 0.3 MPa,respectively.In particular,the desalination performance was tested in vacuum membrane distillation tests by feeding 3.5%(mass)saline solution(NaCl)at 60℃.The composite membranes with larger support pore size and lower PFPE content had higher membrane distillation flux.And for stability tests(testing the 0.22μm membrane coated by 5%(mass)PFPE),the highest MD flux29.08 kg·m^(-2)·h^(-1) and stable salt rejection(over 99.99%)during the period.Except that,the effects of coating material concentration and pore sizes of substrate membrane were also investigated for surface morphology and topography,porosity,mechanical strength and pore size characteristics.This work provided a simple and effective alternative to prepare excellent hydrophobic composite membranes for MD applications.

Atomic layer deposition of Al_2O_3 on porous polypropylene hollow fibers for enhanced membrane performances

Porous polypropylene hollow fiber(PPHF) membranes are widely used in liquid purification. However, the hydrophobicity of polypropylene(PP) has limited its applications in water treatment. Herein, we demonstrate that, for the first time, atomic layer deposition(ALD) is an effective strategy to conveniently upgrade the filtration performances of PPHF membranes. The chemical and morphological changes of the deposited PPHF membranes are characterized by spectral, compositional, microscopic characterizations and protein adsorption measurements. Al_2O_3 is distributed along the cross section of the PP hollow fibers, with decreasing concentration from the outer surface to the inner surface. The pore size of the outer surface can be easily turned by altering the ALD cycles. Interestingly, the hollow fibers become much more ductile after deposition as their elongation at break is increased more than six times after deposition with 100 cycles. The deposited membranes show simultaneously enhanced water permeance and retention after deposition with moderate ALD cycle numbers.For instance, after 50 ALD cycles a 17% increase in water permeance and one-fold increase in BSA rejection are observed. Moreover, the PP membranes exhibit improved fouling-resistance after ALD deposition.

Investigation on the Antitumor Activity of Organotin Compound

Changes in the surface structure of cell membrane and the contents of membrane pro- teins and nuclear DNA of human gastric cancer (BGC-823) cells treated with organotin compound (Et_2SnCl_2phen) were studied with a scanning electron microscope (SEM),a scanning tunneling,micro- scope (STM),and a cytofluorophotometer.It was found that Et_2SnCl_2Phen not only inhibited the cell growth but also remarkably changed the surface structure of the membrane of cancer cells.The surface of Et_2SnCl_2phen treated cancer cells was relatively smooth and showed fewer microvilli under SEM. STM images showed an uneven and loose distribution of the surface of the cell.In comparison with the untreated cancer cells,there was an evident decrease in the content of membrane proteins and nuclear DNA in Et_2SnCl_2phen treated cells.

Fluorite Ce_(0.8)Sm_(0.2)O_(2-δ) porous layer coating to enhance the oxygen permeation behavior of a BaCo_(0.7)Fe_(0.2)Nb_(0.1)O_(3-δ) mixed conductor

Fluorite Ce0.8Sm0.2O2-δ（SDC） nanopowder with a crystallite size of 15 nm was synthesized by a co-precipitation method. An SDC porous layer was coated onto a BaCo0.7Fe0.2Nb0.1O3-δ（BCFN） mixed conductor to improve its oxygen transport behavior. The results show that the SDC-coated BCFN membrane exhibits a remarkably higher oxygen permeation flux（JO2） than the uncoated BCFN in the partial oxidation of coke oven gas（COG）. The maximum JO2 value of the SDC-coated BCFN is 18.28 mL ·min^-1·cm^-2 under a COG/air flux of 177 mL ·min^-1/353 mL ·min^-1 at 875℃ when the thickness of the BCFN membrane is 1 mm; this JO2 value is 23% higher than that of the uncoated BCFN membrane. This enhancement is likely because of the higher oxygen ionic conductivity of SDC, which supplies oxygen vacancies and accelerates oxygen exchange on the membrane/coating layer/gas three-phase boundary.

High Q reflection filter using a gradient-index membrane with a grating surface

High Q reflection filter using a gradient-index(GI) membrane with a grating surface is proposed. The thickness of GI membrane is very small comparing with the traditional multilayer reflection filter or the GI reflection filter, and the GI membrane can also break the restriction of the resonant excitation condition of the conventional guided-mode resonance(GMR) filter. High Q filtering features can be maintained even on the high-index substrate. The grating thickness of the GI membrane filter can be used to select the resonance wavelength with different quality factors(QFs), the reflection peak is blue-shifted, and the QF is decreased from 554.4 to 207.8 as the grating thickness is increased from 50 nm to 150 nm. The gradient coefficient of the GI membrane filter can be used to tailor the number of the reflection channels. The resonant excitations of high order waveguide modes confined in the GI membrane are responsible for the high Q filtering properties with multiple channels.

Torsional wave in a circular micro-tube with clogging attached to the inner surface

In the present paper, we study the torsional wave propagation along a micro-tube with clog- ging attached to its inner surface. The clogging accumulated on the inner surface of the tube is modeled as an ＂elastic membrane＂ which is described by the so-called surface elasticity. A power-series solution is particularly developed for the lowest order of wave propagation. The dispersion diagram of the lowest-order wave is numerically presented with the surface （clogging） effect.