An Approach for Separation and Complete Structural Sequencing of Heparin/Heparan Sulfate-like Oligosaccharides

As members of the glycosaminoglycan (GAG) family, heparin and heparan sulfate (HS) are responsible for mediation of a wide range of essential biological actions, most of which are mediated by specific patterns of modifications of regions of these polysaccharides. To fully understand the regulation of HS modification and the biological function of HS through its interactions with protein ligands, it is essential to know the specific HS sequences present. However, the sequencing of mixtures of HS oligosaccharides presents major challenges due to the lability of the sulfate modifications, as well as difficulties in separating isomeric HS chains. Here, we apply a sequential chemical derivatization strategy involving permethylation, desulfation, and trideuteroperacetylation to label original sulfation sites with stable and hydrophobic trideuteroacetyl groups. The derivatization chemistry differentiates between all possible heparin/HS sequences solely by glycosidic bond cleavages, without the need to generate cross-ring cleavages. This derivatization strategy combined with LC-MS/MS analysis has been used to separate and sequence five synthetic HS-like oligosaccharides of sizes up to dodecasaccharide, as well as a highly sulfated Arixtra-like heptamer. This strategy offers a unique capability for the sequencing of microgram quantities of HS oligosaccharide mixtures by LC-MS/MS

A Nanofilm-Based Fluorescent Sensor toward Highly Efficient Detection of Ethephon

Ethephon (ETH) is widely used to promote fruit ripening and improve fruit quality. However, improper use is harmful to human health and to the environmental safety. Therefore, development of the techniques for on-site and at real-time monitoring of ETH is of importance for its safe use. In this work, we developed a nanofilm-based fluorescence film sensor (FFS) and realized highly efficient detection of ETH in vapor phase, where the detection limit (DL) is <0.2 ppb, the response time is less than 10 s, and the interference is almost free. The unusual sensing performance of the sensor was ascribed to the specific binding of the nanofilm to ETH and to its great porosity, which enables efficient adlayer mass transfer, a requirement for high signal-to-noise ratio. Moreover, visualization-based qualitative sensing is also realized. The nanofilm, a key component of the sensor, was prepared at the humid air/DMSO interface. The building blocks used were a specially designed fluorescent o-carborane derivative (CB-2CHO) and a cross-linker BTN possessing three acylhydrazine groups. The nanofilm as prepared is flexible, uniform, thickness tunable, and photochemically super stable. We believe our effort not only addresses the challenging issue of on-site and at real-time detection of ETH but also provides another route for developing new FFSs via sensing film innovation

Effect of Thioethers on DNA Platination by <i>trans</i>-Platinum Complexes

Increasing evidence indicates that sulfur-containing molecules can play important roles in the activity of platinum anticancer drugs. Although nuclear DNA is retained to be the ultimate target, these platinum compounds can readily react with a variety of other substrates containing a soft donor atom, such as proteins, peptides, and low molecular weight biomolecules, before reaching DNA. In a recent study it was demonstrated that the DNA platination rate of a trans-geometry antitumor drug was dramatically enhanced by methionine binding, thus suggesting that the thioether could serve as a catalyst for DNA platination. In this work we performed detailed studies on the reactions of a widely investigated and very promising trans-platinum complex having two iminoethers and two chlorido ligands, trans-EE, with methionine (Met) and guanosine 5′-monophosphate (GMP). The results show that in the reaction of trans-EE with methionine the bisadduct is the dominant species in the early stage of the reaction. The reaction is also influenced by chloride concentration: at low NaCl the bis-methionine adduct is formed in preference, whereas the monoadduct is favored at high NaCl concentration. Not only the monomethionine complex, trans-PtCl(E-iminoether)2(AcMet), but also the bis-methionine adduct, trans-Pt(E-iminoether)2(AcMet)2, which has already lost both leaving chlorides, can react with GMP to form the ternary platinum complex trans-Pt(E-iminoether)2(AcMet)(GMP). The latter reaction discloses the possibility of direct coordination to DNA of a platinum–protein adduct, in which the two carrier ligands remain intact; this is not the case of cis-oriented platinum complexes, like cisplatin, for which formation of a ternary complex is usually accompanied by loss of at least one carrier ligand. Interestingly, isomerization from S to N coordination of one methionine takes place in the bis-methionine complex at neutral pH, while the monoadduct appears to be stable. The shift from S to N coordination of one methionine in the trans-bis-methionine adduct can easily account for the obtainment of the cis isomer in the bis-chelated Pt(Met-S,N)2 end product

Film Nanoarchitectonics of Pillar[5]arene for High-Performance Fluorescent Sensing: a Proof-of-Concept Study

Substrates play crucial roles for the sensing performances of fluorescent films owing to their effect on the formation of a fluorescent adlayer. However, no such film has been developed through synthesizing a substrate with a defined structure. We herein report a kind of self-standing, uniform, and thickness tunable pillar[5]­arene-based nanofilms to serve as substrates for fabricating fluorescent sensing films. In comparison with a glass plate, the pillar[5]­arene-based nanofilms can ensure spatial and electronic isolation of immobilized fluorophores and circumvent aggregation-caused quenching in a film state. For conceptual proof, a formic acid fluorescent sensing film was developed through simple loading of a fluorophore, a 4-azetidine-1,8-naphthalimide derivative of cholesterol (NA-Ch), onto the prepared nanofilm. Sensing performance studies demonstrated that the fluorescent film showed a sensitive, fast, and highly selective response to formic acid in air with a detection limit of lower than 2.8 mg m–3 and a response time of less than 3 s. Moreover, the sensing is fully reversible and highly repeatable. Further studies showed that the film sensor can be used for fast determination of methanol acidity via vapor sampling. Clearly, innovation of substrates with defined structures can be taken as an effective and efficient way to develop new sensing films via combination with known fluorophores

Selection of HBsAg-Specific DNA Aptamers Based on Carboxylated Magnetic Nanoparticles and Their Application in the Rapid and Simple Detection of Hepatitis B Virus Infection

Aptamers are short single-stranded DNA or RNA oligonucleotides and can be selected from synthetic combinatorial libraries in vitro. They have a high binding affinity and specificity for their targets. Agarose gels, nitrocellulose membranes, and adsorptive microplates are often used as carriers to immobilize targets in the SELEX (systematic evolution of ligands by exponential enrichment) process, but the subsequent separation step is tedious and time-consuming. Therefore, we used magnetic nanoparticles (MNPs) as carriers to immobilize the target, hepatitis B surface antigen (HBsAg), which is convenient for fast magnetic separation. In this study, we first selected DNA aptamers against HBsAg by immobilizing HBsAg on the surface of carboxylated MNPs. The ssDNA library of each selection round was prepared by asymmetric PCR amplification for the next selection round. To obtain aptamer sequences, the final selected products were purified by gel electrophoresis, then cloned, and sequenced. DNA aptamers that specifically bind to HBsAg were successfully obtained after 13 selection rounds. The selected aptamers were used to construct a chemiluminescence aptasensor based on magnetic separation and immunoassay to detect HBsAg from pure protein or actual serum samples. There was a linear relationship between HBsAg concentration and chemiluminescent intensity in the range of 1–200 ng/mL. The aptasensor worked well even in the presence of interfering substances and was highly specific in the detection of HBsAg in serum samples, with a detection limit 0.1 ng/mL lower than the 0.5 ng/mL limit of an ELISA in use at the hospital. This aptasensor can contribute to better detection of hepatitis B virus infection

Unlocking Multicolor Emissions in the Crystalline State through Dimerization and Configurational Transformation of a Single Fluorophore

Multicolor luminescent materials with tunable properties hold great promise for a wide range of applications in materials science. Unfortunately, the conventional approach to achieving multicolor emissions by blending multiple types of fluorophores is hindered by limitations, notably, spectral instability, aggregation-caused quenching, and energy transfer. The pursuit of multicolor emissions from a single type of fluorophore in the solid state has, until now, remained a formidable challenge. In this study, we have introduced N,N′-diphenyl dihydrodibenzo[a,c]-phenazines (DPAC), augmented with two o-carboranyl units, to create a novel fluorophore CbDPAC. The CbDPAC crystal exhibits three distinct emission bands peaking at 405, 470, and 620 nm, respectively, arising from a rich intermolecular interaction network that generates novel emission centers, such as conformational isomers and excimers. This work inspires the rational molecular engineering of smart fluorophores with tailorable properties and inaugurates diverse possibilities for stimuli-responsive luminescent technologies

DataSheet_1_m6A Regulator-Mediated Tumour Infiltration and Methylation Modification in Cervical Cancer Microenvironment.docx

BackgroundN6-methyladenosine (m6A) is the most abundant internal mRNA modification in eukaryotic cells. There is accumulating evidence that m6A methylation can play a significant role in the early diagnosis and treatment of cancers. However, the mechanism underlying the involvement of m6A in cervical cancer remains unclear.MethodsHere, we examined the m6A modification patterns of immune cells in the tumour microenvironments (TMEs) of 306 patients with cervical cancer from The Cancer Genome Atlas dataset and analysed the relations between them according to 32 m6A regulators. Immune infiltration in the TME of cervical cancer was analysed using the CIBERSORT algorithm and single-sample gene set enrichment analysis. The m6Ascore was structured though principal component analysis.ResultsTwo different m6A modification patterns were detected in 306 patients with cervical cancer, designated as m6Acluster A and B. The immune cell infiltration characteristics and biological behaviour differed between the two patterns, with m6Acluster A showing a higher level of immune infiltration. The samples were also divided into two genomic subtypes according to 114 m6A regulatory genes shown to be closely correlated with prognosis on univariate Cox regression analysis. Survival analysis showed that gene cluster B was related to better survival than gene cluster A. Most of the m6A regulators showed higher expression in gene cluster B than in gene cluster A. Single-sample gene set enrichment analysis indicated a higher level of immune cell infiltration in gene cluster A. The m6Ascore signature was examined to determine the m6A modification patterns in cervical cancer. Patients with a high m6Ascore showed better survival, while the low m6Ascore group had a higher mutation frequency and better response to treatment.ConclusionsThis study showed that m6A modification patterns play important roles in cervical cancer. Analysis of m6A modification patterns will yield an improved understanding of the TME in cervical cancer, and facilitate the development of better immunotherapy strategies.</p

Additional file 1: of Gut microbiota from NLRP3-deficient mice ameliorates depressive-like behaviors by regulating astrocyte dysfunction via circHIPK2

Supplementary Materials and Methods and Figures S1–S17. (DOCX 3220 kb