4 research outputs found
Functional Dual-Color Indicator To Achieve in Situ Visualization of Intracellular Glycosylation
A functional dual-color indicator
is designed for in situ visualization
of intracellular glycosylation. Using O-GlcNAcylation as model, the
indicator is constructed on a poly-GlcNAc-coated gold nanoparticle
(AuNP) by assembling dye labeled lectin (FSWGA) and then another dye-labeled
GlcNAc (FGlcNAc) through the two opposite subunits of FSWGA. These
dyes possess negligible overlapping emission and can be quenched by
AuNP. In the presence of intracellular dissociated GlcNAc residue
and O-GlcNAcylated proteins, the assembled FGlcNAc and the conjugate
of FSWGA with FGlcNAc are released from AuNP through the dynamic competitive
conjugation, which lights up the fluorescence of two dyes, respectively,
and provides a simple technique for simultaneously monitoring the
level of O-GlcNAcylated proteins and the total amount of GlcNAc groups
in living cells. The practicality of the protocol for visually monitoring
the biological pathway between intracellular O-GlcNAcylation and cell
surface differentiation-related proteins demonstrates a convenient
and powerful tool for research of glycosylation equilibrium and related
biological processes
Arrayed Profiling of Multiple Glycans on Whole Living Cell Surfaces
An
array-based method for profiling and quantification of multiple
glycans on whole living cell surfaces was developed through combining
DNA encoding technology with DNA microarray. Using four kinds of lectins
as the model to recognize four types of cell surface glycans, the
specific barcode-lectin probes that contained the endonuclease cutting
site were designed. The barcode-lectin probes had the DNA sequences
complementary to four sequences immobilized on a DNA microarray, respectively.
After the living cells were incubated with the mixture of four barcode-lectin
probes, these probes could bind to cell surface through the specific
interaction between the lectins and corresponding glycans. Thus, the
glycans and their amounts could be profiled by releasing the barcodes
from cell surface with endonuclease cleaving, binding the barcodes
to DNA microarray with specific hybridization, and then producing
the amplified fluorescence signal with hybridization chain reaction
(HCR). The HCR was performed with two kinds of Cy5 labeled hairpins.
The average amount of mannose, <i>N</i>-acetylgalactosamine, <i>N</i>-acetylglucosamine, and <i>N</i>-acetylneuraminic
acid on BGC cell was obtained to be 6.8 × 10<sup>7</sup>, 3.8
× 10<sup>7</sup>, 2.1 × 10<sup>8</sup>, and 1.1 × 10<sup>7</sup> moieties per cell, respectively. The proposed method possessed
whole cell surface accessibility, powerful distinguishing capability,
fast recognition kinetics, easy miniaturization, and high throughput
without need of cell pretreatment or labeling. It could become a powerful
tool for elucidation of the complex glycan-related biological processes
Liberation of Protein-Specific Glycosylation Information for Glycan Analysis by Exonuclease III-Aided Recycling Hybridization
A strategy
for information liberation of protein-specific glycosylation
is designed via an exonuclease III-aided recycling “hybridization
and cleavage” process with glycan and protein probes, which
achieves homogeneous quantification of cell surface glycan. The protein
probe contains matching and spacer DNA sequences and an aptamer specific
to target protein. The glycan probe contains a complementary sequence
modified with neighboring fluorescein and quencher, a spacer sequence,
and a dibenzocyclooctyne-amine end to bind azide-tagged glycan. Upon
sequential binding to their targets, the complementary sequences of
two probes approach enough for their hybridization, which leads to
the cleavage of hybridized glycan probe by exonuclease III and followed
recycling “hybridization and cleavage” process of protein
probe with other adjacent glycan probes to release the labeled fluorescein
for obtaining the information on protein-specific glycosylation. This
protocol has been used to in situ quantify EpCAM-specific sialic acid
on MCF-7 cell surface and monitor its variation during drug treatment.
This work demonstrates a powerful quantification tool for research
of glycosylation
Colossal negative thermal expansion over a wide temperature span in dynamically self-assembled MnCo(Ge,Si)/epoxy composites
The achievement of significant negative thermal expansion (NTE) over a wide temperature range (ΔTNTE) has posed a formidable challenge for NTE materials. In the present study, textured MnCo(Ge,Si)/epoxy composites were prepared by magnetic field-assisted dynamic self-assembly of multi-component Mn0.945Co1.055Ge1-xSix particles. The utilization of multi-component particles with tunable transition temperatures significantly amplifies the temperature range over which the NTE occurs, surpassing the limitations of conventional single-component composites. The textured microstructure enables the extension of lattice-level NTE to reach the macroscopic level, which is manifested by a remarkably large NTE coefficient of −328.7 × 10−6/K between 288.2 and 431.1 K. Colossal NTE with a coefficient αL of −328.7 × 10−6/K is achieved over a wide temperature range of 142.9 K between 288.2 and 431.1 K, representing the largest αL among all reported NTE materials.</p