Development of a chemically defined medium for Planctopirus limnophila to increase biomass production

BackgroundPlanctomycetes is a phylum of biofilm-forming bacteria with numerous biosynthetic gene clusters, offering a promising source of new bioactive secondary metabolites. However, the current generation of chemically defined media achieves only low biomass yields, hindering research on these species. We therefore developed a chemically defined medium for the model organism Planctopirus limnophila to increase biomass production.ResultsWe found that P. limnophila grows best with a 10 mM sodium phosphate buffer. The replacement of complex nitrogen sources with defined amino acid solutions did not inhibit growth. Screening for vitamin requirements revealed that only cyanocobalamin (B12) is needed for growth. We used response surface methodology to optimize the medium, resulting in concentrations of 10 g/L glucose, 34 mL/L Hutner’s basal salts, 23.18 mM KNO₃, 2.318 mM NH₄Cl and 0.02 mg/L cyanocobalamin. The analysis of amino acid consumption allowed us to develop a customized amino acid solution lacking six of the amino acids present in Aminoplasmal 10%. Fed-batch cultivation in a bioreactor using the optimized medium achieved a final ΔOD₆₀₀ of 46.8 ± 0.5 after 108 h, corresponding to a cell dry weight of 13.6 ± 0.7 g/L.ConclusionsThe optimized chemically defined medium allowed us to produce larger amounts of biomass more quickly than reported in earlier studies. Further research should focus on triggering P. limnophila biofilm formation to activate the gene clusters responsible for secondary metabolism.How to cite: Kruppa OC, Gerlach D, Fan R, et al. Development of a chemically defined medium for Planctopirus limnophila to increase biomass production. Electron J Biotechnol 2021;54. https://doi.org/10.1016/j.ejbt.2021.09.002.     

栽培式教育的理论基础

当下的教育惟分数论依然十分严重,对人的培养反而成了对学生的压制。为了改变这种现状,我们提出了栽培式教育的理念。栽培式教育的理论基础有人本主义、建构主义、多元智能理论和素质教育等。     

‘It's The Catcher in the Rye… He said it was the kind of book you made your own': Finding Holden in Contemporary YA Literature

Published in 1951,The Catcher in the Rye encapsulated teenage angst. Some time ago David Belbin mused about the influence of Catcher on the proliferation and popularity of YA literature. Salinger's recent death has sparked a renewed interest in his work and more attention on Holden and his inheritors. This article discusses how five recent adolescent novels, with male protagonists, mirror Holden's adolescent paralysis. They exist in a liminal state between childhood and adulthood, attempting to understand the phonies around them. These protagonists help define the nature of the ‘lost’ adolescent in the current golden age of YA literature.     

新时期大学生自我管理研究

社会发展新常态,助推着高校教育教学改革与发展,冲击着固有的教育管理模式,影响着大学生自我管理因素的生成。本文以高校立德树人为宏观视角,切入大学生管理微观课题,结合社会发展新形势、高校管理模式新变化、大学生成长新特点,阐述新时期大学生自我管理"是什么"、"为什么"、"怎么办"的基本道理,剖根问源析原因,立足长远寻对策,以期推动高校可持续发展。     

How can children with mild literacy difficulties be supported at the transition to secondary school? A small‐scale quasi‐experimental study

There is evidence that pupils with weak literacy skills struggle on transition to secondary school. Many experience a drop in attainment in the summer break between the two. A British government‐funded programme of rigorously designed research on boosting literacy at transition had (by 2015) found only four of 15 interventions evaluated had positive effects. This small‐scale quasi‐experimental study investigated the effectiveness of support for pupils with mild literacy difficulties on transition to secondary school. Thirty‐two pupils in three schools were involved; half received the programme. Pairs were matched on reading, spelling, age and gender. Intervention was designed around the individual needs of each pupil, focusing variously on language skills, writing, reading and spelling. The group receiving the programme made modest gains in spelling, reading efficiency and single word reading. The comparison group lost ground, relatively, in all three areas. The results suggest a promising line for more rigorous investigation.     

大学自由教育的生成逻辑与实践路径探析

自由教育时常被冠以自由主义教育的标签,但其精神实质与当前我国倡导的“学生发展核心素养”教育异曲同工,应该得以澄清。自由教育在国家层面上与社会主义本质及核心价值观的全面发展一致,在社会层面上与科教强国的创新驱动一致,在个人层面上与人才培养的人文关怀一致。因此,高校应该把自由教育与人才培养相结合、把自由教育与创新教育相结合、把自由教育与个人成长相结合。     

培养高技能人才与营造学习型组织氛围

高技能人才是指既有比较高的理论素养与知识水平,又具有比较强的操作能力与实践经验的复合人才。由于种种原因,我国目前高技能人才尚严重缺乏,营造学习型组织和高技能人才培养的良好氛围是解决这一问题的有效途径。     

正确培养大学生的数学思维品质

以发展个性思维为目的，探讨了培养学生思维的精度、速度、新度、深度、广度等五个方面的思维品质。     

试论高等教育创新的基本原则

目前 ,我国高等学校进一步扩大招生 ,为适应社会发展的需要各高校在课程设置、教学教法以及后勤社会化等方面都有所创新 ,进行了一系列的改革。我国高等教育的创新是高层次的创新 ,是国家创新体系的支柱和基础 ,它的创新可遵循一些基本原则 ,其中最主要的是个性培养原则、整体培养原则、动态化原则、实践性原则等     

工科院校青年教师立德树人能力提升的路径研究

提升青年教师立德树人能力,是当前高校落实立德树人根本任务、提高人才培养质量的一项重要举措。鉴于工科院校人才培养的特点和要求,应着重从强化思想引导、深化师德建设、坚持创新导向、注重实践锻炼、突出匠心培养、加强人文教育等方面入手,全面提升工科院校青年教师立德树人的能力和水平。