Green and efficient biosynthesis of indigo from indole by engineered myoglobins

With the demand nowadays for blue dyes, it is of practical importance to develop a green and efficient biocatalyst for the production of indigo. The design of artificial enzymes has been shown to be attractive in recent years. In a previous study, we engineered a single mutant of sperm whale myoglobin, F43Y Mb, with a novel Tyr-heme cross-link. In this study, we found that it can efficiently catalyze the oxidation of indole to indigo, with a yield as high as 54% compared to the highest yield (∼20%) reported to date in the literature. By further modifying the heme active site, we engineered a double mutant of F43Y/H64D Mb, which exhibited the highest catalytic efficiency (198 M⁻¹ s⁻¹) among the artificial enzymes designed in Mb. Moreover, both F43Y Mb and F43Y/H64D Mb were found to produce the indigo product with a chemoselectivity as high as ∼80%. Based on the reaction system, we also established a convenient and green dyeing method by dyeing a cotton textile during the biosynthesis of indigo, followed by further spraying the concentrated indigo, without the need of strong acids/bases or any reducing agents. The successful application of dyeing a white cotton textile with a blue color further indicates that the designed enzyme and the dyeing method have practical applications in the future.

Myoglobin (Mb) was redesigned to a green and efficient biocatalysts for the biosynthesis of indigo from indole, exhibiting improved yield, catalytic efficiency and chemoselectivity (as high as ∼80%).     

Brain Natriuretic Peptide for Prevention of Contrast-Induced Nephropathy After Percutaneous Coronary Intervention or Coronary Angiography

BackgroundMany methods reportedly prevent contrast-induced nephropathy (CIN), but the effect of brain natriuretic peptide (BNP) on CIN is unknown. In this study we investigated recombinant BNP use before coronary angiography (CA) or nonemergent percutaneous coronary intervention (PCI) in patients with unstable angina.MethodsOne thousand patients with unstable angina were prospectively evaluated. The patients were randomly assigned to: group A, isotonic normal saline (NaCl 0.9%, 1 mL/kg/h) for 24 hours before CA or PCI; and group B, human recombinant BNP (rhBNP; 0.005 μg/kg/min). Serum creatinine (Scr) levels and estimated glomerular filtration rate were measured before and 24, 48, and 72 hours, and 7 days after the procedure. The primary outcome was CIN incidence defined according to a relative (≥ 25%) or absolute (≥ 0.5 mg/dL and 44 μmol/L, respectively) increase in Scr from baseline within 48 hours. The secondary end points were the changes in the Scr and estimated glomerular filtration rate, before and after the procedure.ResultsContrast volume, a history of diabetes mellitus, and BNP administration independently predicted CIN. The incidence of CIN was significantly greater in group A than in group B (14.8% vs 5.6%; P < 0.01). Renal function was less compromised in patients who received rhBNP. The Scr of all patients with CIN remained increased for 24 hours, but it was lower and recovered faster in patients who received rhBNP.ConclusionsrhBNP administration before CA or PCI protects renal function and can significantly decrease CIN incidence.     

A nano-sized Cu-MOF with high peroxidase-like activity and its potential application in colorimetric detection of H2O2 and glucose

Peroxidase widely exists in nature and can be applied for the diagnosis and detection of H₂O₂, glucose, ascorbic acid and other aspects. However, the natural peroxidase has low stability and its catalytic efficiency is easily affected by external conditions. In this work, a copper-based metal–organic framework (Cu-MOF) was prepared by hydrothermal method, and characterized by means of XRD, SEM, FT-IR and EDS. The synthesized Cu-MOF material showed high peroxidase-like activity and could be utilized to catalyze the oxidation of o-phenylenediamine (OPDA) and 3,3′,5,5′-tetramethylbenzidine (TMB) in the presence of H₂O₂. The steady-state kinetics experiments of the oxidation of OPDA and TMB catalyzed by Cu-MOF were performed, and the kinetic parameters were obtained by linear least-squares fitting to Lineweaver–Burk plot. The results indicated that the affinity of Cu-MOF towards TMB and OPDA was close to that of the natural horseradish peroxidase (HRP). The as-prepared Cu-MOF can be applied for colorimetric detection of H₂O₂ and glucose with wide linear ranges of 5 to 300 μM and 50 to 500 μM for H₂O₂ and glucose, respectively. Furthermore, the specificity of detection of glucose was compared with other sugar species interference such as sucrose, lactose and maltose. In addition, the detection of ascorbic acid and sodium thiosulfate was also performed upon the inhibition of TMB oxidation. Based on the high catalytic activity, affinity and wide linear range, the as-prepared Cu-MOF may be used for artificial enzyme mimics in the fields of catalysis, biosensors, medicines and food industry.

A Cu-MOF with high peroxidase-like activity was prepared and could be used for colorimetric detection of H₂O₂ and glucose with high selectivity and good linear range (50–500 μM).     

半夏基因组DNA的提取及鉴定

目的探讨不同DNA提取方法对半夏DNA质量及RAPD-PCR标记结果的影响。方法对用不同方法提取的DNA进行电泳、紫外吸收A260/A280和RAPD-PCR分析。结果不同方法提取的DNA质量和产率差异不显著,对RAPD结果无影响。结论半夏在DNA提取前加入氯仿对材料预处理,可获得较高质量的DNA进行PCR扩增。     

半夏种内各变异类型主要形态学性状比较研究

目的为半夏各变异类型提供形态学的鉴别和分类依据。方法系统观察并测量各变异类型主要形态学性状,采用多角形图比较其相似性和差异性程度。结果生殖器官中,各变异类型间各性状的差异性较小,但有一个变异趋势,即阔叶类型的雌雄花序长和宽,雌雄间隔,管部长和宽与其它类型相比,数值略小。营养器官中,以叶片长宽比值即叶形的变化最为明显,其它性状在各变异类型间相似。结论叶片长宽比值在各变异类型间差异显著,可作为各变异类型鉴别和分类的依据。     

父母教养方式对中专生身心健康的影响

目的探讨父母教养方式对中专生身心的影响，为中专生的健康促进提供依据。方法采用父母教养方式评价量表（EMBU）和症状自评量表（SCL-90），对南充市两所中专学校190名一年级新生进行测查。结果症状自评量表筛查出有心理问题者19人，占10.50%。父亲惩罚严厉、偏爱被试与SCL-90躯体化和敌对因子呈显著正相关；母亲情感温暖、理解与躯体化呈显著负相关，过干涉和过保护与总分、躯体化、敌对和恐怖因子呈显著正相关，而母亲惩罚严厉与SCL-90总分及各因子呈显著正相关。结论父母教养方式与中专生身心健康密切相关。     

谈PBL的理论与实践

PBL是一种让学生在真实情境中思考、学习和行动的实验教学法,是建构主义理论指导下的一种新的教学模式.目前,PBL已从当初的医学教育领域走向其它学科教育领域.文章以PBL在<教育传播科学研究方法>中的应用为例,阐述了PBL的教学流程.     

头脑风暴法在Webquest教学模式中的应用

介绍了头脑风暴法在Webquest教学模式中的融合流程,通过对Webquest教学流程的分析,在参照头脑风暴法与Wequest应用原则的基础上,总结出融入头脑风暴思想后Webquest的教学设计流程.调查发现,在课堂教学过程中应用头脑风暴法,不仅可以提高学生的学习兴趣,而且可以高效提高学生的创造性思维能力,为教学效果的改善以及创新型人才的培养提供有力保障.     

数据挖掘在教学管理中的应用研究

数据挖掘是一种新的信息处理技术.文章在对数据挖掘进行概述的基础上,以某高校教务管理系统应用为例,说明在学校教学管理中,数据挖掘能从海量数据中找出有价值、有意义的数据,为教学管理的科学决策提供参考,既提高了教学管理工作的效率和质量,又减少了工作人员的工作量.