Reversible Insertion of CO_(2)into a Bis(formazanate)Magnesium Complex

The capture,storage,and release of CO_(2)is one of the most pressing issues in chemistry.Herein,we designed bis(formazanate)magnesium complexes as precursors,which were synthesized by straightforward transamination between the neutral formazan[PhNNC(4-tBuPh)NNHPh](LH)and[Mg{N(SiMe_(3))_(2)}_(2)].Depending on the solvent,either the homoleptic complex[L_(2)Mg]or the thf-coordinated complex[L_(2)Mg(thf)]was isolated.Reaction of the solvent-free complex[L_(2)Mg]with CO_(2)led to stoichiometric insertion into one of the four Mg–Nbonds with concomitant rearrangement of the ligand scaffold which adopts a trinuclear cagelike structure.The insertion reaction is reversible depending on thermolysis or treatment with tetrahydrofuran,which is corroborated by density functional theory calculations.This showcases the first example of reversible uptake of CO_(2)by an s-block coordination compound.

Boron difluoride formazanate dye for high-efficiency NIR-Ⅱ fluorescence imaging-guided cancer photothermal therapy

The small molecular second near-infrared(NIR-Ⅱ, 1000–1700 nm) dye-based nanotheranostics can concurrently combine deep-tissue photodiagnosis with in situ phototherapy, which occupies a vital position in the early detection and precise treatment of tumors. However, the development of small molecular NIR-Ⅱ dyes is still challenging due to the limited electron acceptors and cumbersome synthetic routes.Herein, we report a novel molecular electron acceptor, boron difluoride formazanate(BDF). Based on BDF, a new small molecular NIR-Ⅱ dye BDF1005 is designed and synthesized with strong NIR-I absorption at 768 nm and bright NIR-Ⅱ peak emission at 1034 nm. In vitro and in vivo experiments demonstrate that BDF1005-based nanotheranostics can be applied for NIR-Ⅱ fluorescence imaging-guided photothermal therapy of 4T1 tumor-bearing mice. Under 808 nm laser irradiation, tumor growth can be effectively inhibited. This work opens up a new road for the exploitation of NIR-Ⅱ small molecular dyes for cancer phototheranostics.

小鼠脑片Formazan定量测量方法评价缺血性损伤及神经保护作用

目的 建立一种定量测量 2 ,3,5 三苯基四氮唑(TTC)红色还原产物formazan的方法 ,用于评估离体脑片缺血性损伤以及依达拉奉和ONO 10 78的神经保护作用。方法 以TTC为底物在小鼠脑片生物合成formazan标准品 ,并进行分离、纯化和鉴定。小鼠脑片以缺氧缺糖 (OGD)方法诱导损伤 ,用分光光度法在 4 90nm处测量皮质和纹状体formazan合成量。依达拉奉和ONO 10 78加入培养液 ,观察其神经保护作用。结果 合成并纯化了formazan标准品 ,其纯度为 0 993,线性测量范围在 0 0 5～ 1g·L-1。OGD减少formazan合成 ,与处理时间有依赖性。依达拉奉 (0 0 1～ 1μmol·L-1)抑制OGD诱导的formazan合成减少 ,而ONO 10 78无作用。结论 定量测量formazan是一种评价离体脑片损伤及药物神经保护作用的有用方法。

MTT比色法测定超氧阴离子自由基

利用 苯三酚 (py)在碱性环境下可自氧化产生O2 ·,MTT可接受O2·而生成兰紫色的甲 的原理 ,建立一种新的O2 ·检测方法 .标准反应体系是MTT10 μl,PY10 μl,样品适量 ,反应 15min后加酸性SDS 0 .5ml,反应最适 pH值为 8.2 ,终止反应 pH值为 4 .9,测定波长为 5 70nm ,观察了维生素E和广枣总黄酮清除O2·的作用 .该法简单、易行、稳定性好 ,适合检测中蒙药抗氧化作用 .

MTT法检测细菌细胞数的主要影响因素分析

MTT法是生物活细胞计数的灵敏、快速和便捷方法。报告对MTT法应用于细菌细胞数定量分析时的分析前培养时间、MTT反应时间、MTT剂量和检测波长等主要影响因素的分析结果,同时报告MTT反应产物溶解检测与直接检测,以及MTT法与平板菌落计数法定量检测的结果比较。结果如下:Formazan生成量与细菌活细胞数呈正相关,对数生长期变化最明显;MTT为0.25 mg/mL,反应2 h时吸光值与菌落数具有良好的线性关系(r=0.999 8);Formazan的最大吸收波长为570～580 nm;MTT反应产物溶解检测和直接检测结果经统计学分析无显著性差异(P>0.05);细菌细胞数在107～109 cfu/mL范围内,MTT法与菌落计数法定量结果呈现良好的线性关系(r≥0.991 7)。

Effect of assay conditions on the measurement of dehydrogenase activity of <i>Streptomyces venezuelae</i>using triphenyl tetrazolium chloride

Jadomycin is an antibiotic that has shown activities against bacteria, yeasts and fungi as well as cytotoxic properties to cancer cells. Because of the wide range of its inhibitory actions, jadomycin shows promise as a novel antibiotic and cancer treatment drug. Streptomyces venezuelae are aerobic bacteria that produce jadomycin and the size of bacterial population can significantly affect the yield of jadomycin. Therefore, the bacterial population must be accurately measured in order to standardize the reproducibility of jadomycin production process. In this study, a dehydrogenase activity measurement test, using triphenyl tetrazolium chloride (TTC), was used to measure the dehydrogenase activity of Streptomyces venezuelae during growth in maltose-yeast extract-malt extract (MYM) broth. The aims were to evaluate the effectiveness of the test for measuring microbial growth and to study the effects of the test conditions (incubation time, incubation temperature and medium pH) on triphenyl formazan (TF) yield. The results showed that the TF yield was highly correlated to the optical density. The highest TF yield was observed at a pH of 6 at all incubation times and temperature. Lower TF yields were obtained at higher temperature (40 and 50oC) compared to those obtained at lower temperatures (22 and 30oC). The difference between the yields obtained at 22oC and 30oC were not significant. The differences between incubation time were also not significant. The recommended test conditions are an incubation time of 1 hour at a temperature of 30oC and a pH of 6 followed by three extractions using methanol.

Activation and IL-1B secretion of human peripheral phagocytes infected with Actinomadura madurae,Nocardia asteroides and Candida albicans

Objective: To evaluate the ability of Actinomadura madurae(A. madurae) and Nocardia asteroids(N. asteroides), using Candida albicans(C. albicans) as prototypic control, to elicit the activation and IL-1β secretion of blood phagocytic cells from healthy donors. Methods: Microcopic evaluation of phagocytosis/activation, cell viability and spectrophotometric quantitation of endocytosis/activation, were assessed by using formazan blue test in human blood phagocytes infected with C. albicans, A. madurae or N. asteroides treated with either normal human serum(NHS) or with decomplemented NHS. Interlukin-1β from culture supernatants of infected polymorphonuclear was tested by ELISA kit assay. Results: Microscopic assay showed that phagocytosis and activation of adherent mononuclear phagocytes were greater with C. albicans followed by A. madurae and then by N. asteroides. Spectrophotometric assay in polymornuclear phagocytes infected with NHS-treated pathogens indicated that activation was similarly higher by C. albicans and A. madurae and lower by N. asteroides. Kinetic assays in infected polymorphonuclear cells showed that viability was decreased by C. albicans and N. asteroides or unaffected with A. madurae. Levels of IL-1β at 8 h of incubation were higher with C. albicans followed by A. madurae whereas lower levels were found with N. asteroides. Conclusions: The extent of cell-viability and activation as well IL-1β secretion may be related with the virulence of C. albicans and N. asteroides and other parameters remain to be explored for assesing the virulence of A. madurae.

One-Pot Four Component Reaction for the Synthesis of Formazans in an Environmentally Benign Procedure Mediated by KHSO₄

A microwave mediated solvent free one pot synthesis of formazans is developed using the solid acid, KHSO4. The products were obtained in a short reaction time in high yield. This study was undertaken to find an alternative and green method for the synthesis of formazans in the absence of corrosive mineral acids, buffered solutions and volatile organic compounds (VOCs).