DNA aptamers against the MUC1 tumour marker: design of aptamer–antibody sandwich ELISA for the early diagnosis of epithelial tumours

Aptamers are functional molecules able to bind tightly and selectively to disease markers, offering great potential for applications in disease diagnosis and therapy. MUC1 is a well-known tumour marker present in epithelial malignancies and is used in immunotherapeutic and diagnostic approaches. We report the selection of DNA aptamers that bind with high affinity and selectivity an MUC1 recombinant protein containing five repeats of the variable tandem repeat region. Aptamers were selected using the SELEX methodology from an initial library containing a 25-base-long variable region for their ability to bind to the unglycosylated form of the MUC1 protein. After ten rounds of in vitro selection and amplification, more than 90% of the pool of sequences consisted of target-binding molecules, which were cloned, sequenced and found to share no sequence consensus. The binding properties of these aptamers were quantified using ELISA and surface plasmon resonance. The lead aptamer sequence was subsequently used in the design of an aptamer–antibody hybrid sandwich ELISA for the identification and quantification of MUC1 in buffered solutions. Following optimisation of the operating conditions, the resulting enzyme immunoassay displayed an EC₅₀ value of 25 μg/ml, a detection limit of 1 μg/ml and a linear range between 8 and 100 μg/ml for the MUC1 five tandem repeat analyte. In addition, recovery studies performed in buffer conditions resulted in averaged recoveries between 98.2 and 101.7% for all spiked samples, demonstrating the usability of the aptamer as a receptor in microtitre-based assays. Our results aim towards the formation of new diagnostic assays against this tumour marker for the early diagnosis of primary or metastatic disease in breast, bladder and other epithelial tumours. Figure An aptamer-antibody two-dimentional immunoassay for MUC1     

Synthesis of an antimetastatic tetrasaccharide β-D-Gal-(1→4)-β-d-GlcpNAc-(1→6)-α-D-Manp-(1→6)-β-D-Manp-OMe

An antimetastatic tetrasaccharide T₁,β-D-Gal-（1→4）-β-D-GlcpNAc-（1→6）-α-D-Manp-（1→6）-β-D-Manp-OMe,was synthesized with two approaches.The first approach was a conventional method employing thioglycoside and Koenigs-Knorr glycosylation reaction in 24%overall yield.The second one was a novel route through the azidoiodo-glycosylation strategy by using 2-iodo-2-deoxylactosyl azide as the donor in 36%overall yield.     

Enhancive Synthesis of(±)-1β,11-Diol-4-en-eudesmol

An enhancive synthesis of (±)-1β, 11-diol-4-en-eudesmol,starting from 2-chloroacrylonitrile, is described. The effect oftemperature on the Diels-Alder reaction of 2-chloroacrylonitrilewith 2-methylfuran and the condition of cationic cyclization ofdiene were discussed in detail.     

Identification of cyclicsulfonamide derivatives with an acetamide group as 11β-hydroxysteroid dehydrogenase 1 inhibitors

In the continuation of our 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) inhibitor research, cyclic sulfonamide derivatives with an acetamide group at the 2-position were synthesized and evaluated for their abilities to inhibit 11β-HSD1. Among this series, Compound 34 showed good in vitro activity toward human 11β-HSD1, selectivity against 11β-HSD2, microsomal stability, good pharmacokinetic and safety profiles human ether-a-go-go related gene (hERG and cytochrome P450 (CYP)). Also, a docking study explained the activity difference between human and mouse 11β-HSD1.     

In situ fluorescence imaging of fungi via (1,3)-β-d-glucan aptamer and tyramide signal amplification technology

Fungal infections are hazardous to human health that has drawn wide attention. In this work, a specific and sensitive method combing the recognition of aptamer to (1,3)-β-d-glucan and tyramide signal amplification technology was proposed for the in situ fluorescence imaging of fungi. Fungi could be distinctly observed by fluorescence microscope rapidly. This method provides morphology and diagnostic information for identifying fungi. The combination of aptamer and tyramide signal amplification technology is a promising tool for the detection of fungi, bacteria and even eukaryotic cell with the virtue of biomarkers.     

Comparison of a homology model and the crystallographic structure of human 11β-hydroxysteroid dehydrogenase type 1 (11βHSD1) in a structure-based identification of inhibitors

Summary Human 11β-hydroxysteroid dehydrogenase type 1 (11βHSD1) catalyzes the interconversion of cortisone into active cortisol. 11βHSD1 inhibition is a tempting target for the treatment of a host of human disorders that might benefit from blockade of glucocorticoid action, such as obesity, metabolic syndrome, and diabetes type 2. Here, we report an in silico screening study aimed at identifying new selective inhibitors of human 11βHSD1 enzyme. In the first step, homology modeling was employed to build the 3D structure of 11βHSD1. Further, molecular docking was used to validate the predicted model by showing that it was able to discriminate between known 11βHSD1 inhibitors or substrates and non-inhibitors. The homology model was found to reproduce closely the crystal structure that became publicly available in the final stages of this work. Finally, we carried out structure-based virtual screening experiments on both the homology model and the crystallographic structure with a database of 114’000 natural molecules. Among these, 15 molecules were consistently selected as inhibitors based on both the model and crystal structures of the enzyme, implying a good quality for the homology model. Among these putative 11βHSD1 inhibitors, two were flavonone derivatives that have already been shown to be potent inhibitors of the enzyme.     

Synthesis of 1-(3-(1,2,4-triazol-1-yl)-2,3,6-trideoxy-L-arabino-hexofuranosyl)uracils via an α,β-unsaturated aldehydrohexose

Summary Mercuric catalyzed hydrolysis of acetylatedL-rhamnal1 gave the ,-unsaturated aldehyde2. 1,2,4-Triazole was coupled, in a Michael type addition reaction, to2 at C-3 in the presence of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) to give, after acetylation at the anomeric center, an anomeric mixture of 1,5-di-O-acetyl-3-(1,2,4-triazol-1-yl)-2,3,6-trideoxy-L-arabino-hexofuranose (3). Reaction of3 with silylated 2,4-dihydroxypyrimidines4 in the presence of trimethylsilyl triflate as catalyst followed by deprotection with 33% methylamine in absolute ethanol afforded the corresponding nucleosides7 and8.

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Synthese von 1-(3-(1,2,4-Triazol-1-yl)-2,3,6-trideoxy-L-arabino-hexofuranosyl)uracilen über eine ,-ungesättigte Aldohexose

Zusammenfassung Die quecksilberkatalysierte Hydrolyse von acetyliertemL-Rhamnal1 ergab die ,-ungesättigten Aldehyde2. 1,2,3-Triazol wurde in Gegenwart von 1,8-Diazabicyclo[5.4.0]-7-undecen mittels einer Addition vom Michael-Typ an C-3 von2 gekoppelt und ergab dann nach Acetylierung am anomeren Zentrum eine anomere Mischung von 1,5-Di-O-acetyl-3-(1,2,4-triazol-1-yl)-2,3,6-trideoxy-L-arabino-hexofuranose (3). Die Reaktion von3 mit silyliertem 2,4-Di-hydroxypyrimidinen4 in Gegenwart von Trimethylsilyltriflat in absolutem Ethanol ergab die entsprechenden Nucleoside7 und8.

     

8β-hydroxyeremophil-7(11)-ene-12,8α(4β,6α)-diolide分子的晶体结构

8β-hydroxyeremophil-7(11)-ene-12,8α(4β,6α)-diolide was isolated from the Ligularia intermedia and char- acterized by MS, multi NMR and X-ray single crystal diffraction. Its crystal structure was determined as in a orthorhombic type, with space group P212121 with a=6.8519(5), b=10.7191(8), c=18.5942(14) oA, V =1365.67(18) oA3, Z=4, and the calculated density is 1.354 mg/m3. F(000)=592, μ=0.101 mm-1.     

(1-1)-Linked C-Disaccharides – Synthesis of Bis(β-D-Galactopyranosyl)Methane

ABSTRACT

Bis[C-(galactal-1-yl)]carbinol derivative 2, which is readily obtained by transformation of galactal into a vinyl carbanion and then reaction with a C₁-electrophile, was transformed into the title compound (1b). The procedure required first temporary protection of the carbinol hydroxy group and subsequent transformation of the galactal moiety into the galactopyranosyl moiety. Then deoxygenation of the carbinol and final deprotection could be carried out.     

Synthesis of 1-N-(β-D-Glucopyranosyl)- and 1-N-(1-Deoxy-2,3,4,5,6-penta-O-acetyl-D-galactit-1-yl)ascorbigens

The 1-N-carbohydrate-containing ascorbigens 1-N-(-D-glucopyranosyl)ascorbigen and 1-N-(1-deoxy-2,3,4,5,6-penta-O-acetyl-D-galactit-1-yl)ascorbigen were synthesized.     

Probing the Binding of 4β-(Benzoyl-thioureido)-4-deoxypodophyllotoxin to Human Serum Albumin by Molecular Spectroscopy

Journal of Solution Chemistry - The binding interaction of 4β-(benzoyl-thioureido)-4-deoxypodophyllotoxin (HY-1) with human serum albumin (HSA) was investigated by fluorescence,...     

Synthesis of stigmasteryl (β1→4)-oligoglucosides

Stigmasteryl (β1→4)-oligoglucosides were prepared with cellobiose, cellotriose, and cellotetraose as glycan chains. For the preparation of the peracetylated oligoglucosyl donors anomeric acetate was deprotected and the respective hemiacetals were converted into trichloroacetimidates. Glycosylation with stigmasterol yielded both α- and β-anomers because during the treatment with Lewis acid the 2-OAc is cleaved to some extent; thus, with the emerging hydroxyl group neighboring group participation does not take place. Due to their different number of hydroxyl groups (0 vs. 1) separation of the two products proved to be facile. Saponification led to the desired stigmasteryl glucosides.     

Synthesis of Two Isomeric Tetrasaccharides 0-α-L-Fucopyranosyl-(1→3) and (1→4)-0-(2-Acetamido-2-Deoxy-β-D-Glucopyranosyl)-(1→3)-0-(β-D-Galactopyranosyl)-(1→4)-D-Glucopyranose and a Related Tetrasaccharide 0-α-L-Fucopyranosyl-(1→3)-0-(2-Acetamido-2-Deoxy-β-D-Glucopyranosyl-(1→6)-0-(β-D-Galactopyranosyl)-(1→4)-D-Glucopyranose

ABSTRACT

Synthesis of three tetrasaccharides, namely, 0-α-L-fucopyranosyl-(1→3)-0-(2-acetamido-2-deoxy-β-D-glucopyranosyl)-(1→3)-0-(β-D-galactopyranosyl)-(1→4)-β-D-glucopyranose (7), 0-α-L-fucopyranosyl-(1→4)-0-(2-acetamido-2-deoxy-β-D-glucopyranosyl)-(1→3)-0-(β-D-galactopyranosyl)-(1→4)-D-glucopyranose (9), and 0-α-L-fucopyransoyl-(1→3)-0-(2-acetamido-2-deoxy-β-D-glucopyransoyl)-(1→6)-0-(β-D-galactopyranosyl)-(1→4)-D-glucopyranose (15) has been described. Their structures have been established by ¹³C NMR spectroscopy.     

人体β-珠蛋白基因5′-旁侧DNA序列内的负调控区域1(NCR1)与HMG蛋白质(1+2)的相互作用

利用分子生物学技术和扫描隧道显微镜方法首次观察到HMG蛋白质(1+2)和人体β-珠蛋白基因的5′-旁侧DNA序列内的一个负调控区域(NCR1)相互作用的构象,这类蛋白质能将线状的DNA片段(～200bp)折叠起来,形成一个环状结构(直径70±6A)和°一条似乎呈现左手螺旋(z-from)的线状DNA尾巴。