腺苷与人血清白蛋白间相互作用的荧光光谱及分子模型法研究

在模拟人体生理条件下,结合紫外光谱和分子对接模型运用荧光光谱研究了腺苷与人血清白蛋白(HSA)间的键合作用。腺苷有较强的能力猝灭人血清白蛋白的内源荧光,且根据Stern-Volmer方程判断出猝灭机制为静态猝灭。本文运用相应的荧光值和Vant’Hoff热力学方程求得了不同温度下的结合常数(K)以及一些热力学参数,如焓变(ΔH)和熵变(ΔS)。结果表明：键合过程中疏水作用力对新化合物的稳定性起主要作用,这与分子对接模型方法研究的结果基本一致。另外还研究了常见离子对结合常数的影响。     

Dioxopiperazine Alkaloids Produced by the Marine Mangrove Derived Endophytic Fungus Eurotium rubrum

Cultivation of the fungal strain Eurotium rubrum, an endophytic fungus that was isolated from the inner tissue of stems of the mangrove plant Hibiscus tiliaceus, resulted in the isolation of two new dioxopiperazine derivatives, namely, dehydrovariecolorin L ( 1 ) and dehydroechinulin ( 2 ), together with eight known dioxopiperazine compounds including variecolorin L ( 3 ), echinulin ( 4 ), isoechinulin A ( 5 ), dihydroxyisoechinulin A ( 6 ), preechinulin ( 7 ), neoechinulin A ( 8 ), neoechinulin E ( 9 ), and cryptoechinuline D ( 10 ). The structures of the isolated compounds were determined by extensive analysis of their spectroscopic data as well as by comparison with literature. Compounds 1, 2, 9 , and 10 were investigated for their α,α‐diphenyl‐β‐picrylhydrazyl (DPPH) radical‐scavenging activity. In addition, the new compounds, 1 and 2 , were evaluated for their cytotoxic activity against the P‐388, HL‐60, and A549 cell lines.     

Simple and Sensitive Electrochemiluminescence Method for Determination of Bisphenol a Based on its Inhibitory Effect on the Electrochemiluminescence of Luminol

An electrochemiluminescence inhibition method has been developed for the determination of bisphenol A based on studying the inhibition phenomena of bisphenol A to the electrochemiluminescence of luminol. There is a linear relationship between the inhibitive intensity of electrochemiluminescence and the concentration of bisphenol A in the range of 4.4 × 10^?7 to 2.2 × 10^?5 mol/l. The method was successfully applied to the determination of bisphenol A in hot water in contact with commercially available table‐water bottle samples.     

Total Synthesis of 4′′‐O‐Acetylmananthoside B Part II: Synthesis of the Disaccharide Fragment

A disaccharide compound, p‐methoxyphenyl 2,3,4‐tri‐O‐benzyl‐β‐L‐arabinopyranosyl‐(1→6)‐2‐O‐benzyl‐3,4‐di‐O‐acetyl‐β‐D‐galactopyranoside ( 17 ), was successfully synthesized from two monosaccharides L‐arabinose and D‐galactose and fully characterized. This compound can be used to build a natural product 4″‐O‐acetylmanan thoside B, which was isolated from the leaves and stems of a kind of Vietnamese Acanthaceae Justicia patentiflora.     

水杨醛肟铜络合物中性载体高选择性水杨酸根电极的研究

采用合成的Schiff碱金属络合物水杨醛肟铜(Ⅱ)、锌(Ⅱ)、镍(Ⅱ)为中性载体制备阴离子选择性电极。结果表明水杨醛肟铜(Ⅱ)对水杨酸根(Sal-)具有高选择性及优良的电位响应性能,电极呈现反Hofmeister选择性行为,其选择性次序为Sal->ClO4->SCN->I->NO2->NO3->Br->Cl->OAc->SO42-。采用交流阻抗技术和紫外可见光谱技术研究了电极的响应机理。该电极具有响应快、重现性好、检出限低和制备简单等优点。将电极用于药品及人体尿液分析,结果令人满意。     

Anions bonded on the supramolecular hydrogel surface as the growth center of biominerals

In this work, a supramolecular hydrogel formed from N,N',N'-tris(3-pyridyl)-trimesic amide was reported to serve as the matrix for the growth of biominerals. The organic hydrogel scaffold contains nitrogen heterocyclic ring and amide groups that can bind anions of the mineral (specially here, carbonate ions and phosphate ions) through hydrogen bonding interactions and act as the biomineralization active sites for growing biominerals. Calcium carbonate nucleated on the site of the hydrogel fiber where carbonate ions bonded and left obvious hydrogel fiber prints on the obtained product. Calcium phosphate grew into curved platelike nanostructures along the hydrogel fibrous network. XRD pattern and FT-IR spectra confirmed the formation of minerals on the hydrogel. The results indicate that the hydrogen bonding interaction can provide strong enough binding force for the growth of the minerals on organic scaffolds. Our finding extends the organic scaffolds into biodegradable small molecule hydrogels and also extends the growth centers of the minerals from conventional carboxylate groups binding Ca(2+) to amide and pyridyl groups binding PO(4)(3-).     

A New Hapten for Immunoassay of Aldicarb

Aldicarb, 2-methyl-2-(methylthio)propionaldehyde O-(methylcarbamoyl)oxime, is a systemic N-methylcarbamate insecticide and has been used on a variety of crops. It is moderately water soluble and considered as one of the most acutely toxic pesiticides. Ald…     

Antimicrobial tunicamycin derivatives from the deep sea-derived Streptomyces xinghaiensis SCSIO S15077

Abstract

Tunicamycin E (1), featuring a methyl substitution at C-10′, was isolated from marine-derived Streptomyces xinghaiensis SCSIO S15077 originated from the South China Sea sediment together with six known compounds, tunicamycin B (2), tunicamycin X (3), tunicamycin A (4), streptovirudin D₂ (5), tunicamycin C (6), and tunicamycin C₃ (7). The structure of compound 1 was elucidated by detailed spectroscopic data analyses. All the compounds exhibited strong to moderate antibacterial activity against Gram-positive bacteria Bacillus thuringiensis BT01 and B. thuringiensis W102 with MIC values ranging from 0.008 to 2 μg/mL. Moreover, compounds 1–7 exhibited moderate antifungal activity against Candida albicans ATCC 96901 and C. albicans CMCC (F) 98001 with MIC values ranging from 2 to 32 μg/mL. This is the first report that tunicamycins exhibit antimicrobial activities against B. thuringiensis, C. albicans CMCC (F) 98001 and a fluconazole resistant strain C. albicans ATCC 96901.     

Biomimetic Asymmetric Reduction of Quinazolinones with Chiral and Regenerable NAD(P)H Models

A facile approach to chiral dihydroquinazolinone derivatives has been described via biomimetic asymmetric reduction of quinazolinones with chiral and regenerable NAD(P)H models. The utility of this method was demonstrated by a concise synthesis of the bromodomain protein divalent inhibitor.     

Lithium dioxobis[trioxoiodato(V)]vanadate,Li[VO2(IO3)2]

The title compound represents a new structure type, in which distorted VO₆ octa­hedra are bridged by iodate groups to form infinite two‐dimensional [VO₂(IO₃)₂]⁻ layers that are separated by octa­hedrally coordinated Li⁺ cations.