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

《Electronic Journal of Biotechnology》2021

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.  相似文献   

Investigating Student Perceptions of a Dissection-Based Undergraduate Gross Anatomy Course Using Q Methodology     

Jessica N. Byram  Jason M. Organ  Michael Yard  Naomi A. Schmalz 《Anatomical sciences education》2020,13(2):149-157

The demand for upper-level undergraduate dissection-based anatomy courses is growing, as professional programs require more advanced anatomy training prior to matriculation. To address this need, Indiana University School of Medicine (IUSM) partnered with Indiana University-Purdue University Indianapolis—a large, urban, life science-focused campus nearby to IUSM—to offer an undergraduate, dissection-based course in regional gross anatomy. Because this is a new course, a deeper post-course evaluation of student perceptions was conducted using Q methodology. In this study, Q methodology was used to evaluate student views of the overall course structure, pre-laboratory materials and activities, assessments, and quality of instruction. Of the 15 students in the spring semester 2018 cohort, 80% (n = 12) participated in the evaluation, and 10 of those students followed up with written explanations for their rationale in selecting the four statements with which they most strongly agreed and disagreed. The Q methodology sorted the students into one of three statistically significant groups: Motivated Dissectors (n = 6), Traditional Students (n = 3), and Inspired Learners (n = 3). Motivated Dissectors and Inspired Learners felt strongly that the course did not encourage self-directed learning and that the pre-laboratory materials were not adequate to prepare them for quizzes. Traditional Students, however, disagreed, having a favorable opinion of the pre-laboratory materials, even though this group felt most strongly that the amount of material covered in the course was overwhelming. This study demonstrates the utility of Q methodology to evaluate courses to elucidate student perspectives and inform future course modifications.  相似文献   

Modelling Quoting in Newswriting: A Framework for Studies on the Production of News     

Lauri Haapanen 《Journalism Practice》2020,14(3):374-394

ABSTRACT

The Mediated Social Communication (MSC) approach considers mass media a venue for opposing and complementary societal groups to publicly negotiate socially relevant topics. This negotiation is conducted through representatives of these groups and mediated by journalists. Inspired by the MSC approach, this paper presents an empirically grounded model that structures the mediating process through the process of quoting. By identifying the key phases of newswriting as sub-processes of quoting, the paper argues that journalists (1) decide on a topical issue to be addressed (topicalisation), (2) identify groups of people who are linked to this issue (societal localisation), (3) pick some people as representatives of these societal groups (personalisation), and (4) verbalise these people's points of view, often by means of quoting, inter alia (verbalisation). The four-phase model is then operationalised into a data collection method that facilitates access to and fosters new insights into the subtle dynamics of newswriting. Hitherto, these dynamics have often remained obscure, because the craft ethos is adopted as tacit knowledge through implicit socialisation and is therefore difficult for journalists to verbalise. The paper concludes by calling for reconsideration of journalists’ role as gatekeepers who decide which issues and voices are heard in public discourse.  相似文献   

Teaching for developmental growth: learning partnerships and student development in graduate education in China     

Yuhao Cen 《Teaching in Higher Education》2018,23(1):30-46

Teaching and learning in higher education can integrate and accomplish student developmental goals in addition to promoting student learning of subject matter knowledge and transferrable skills. Drawn from the theoretical concept of self-authorship, the Learning Partnerships Model was implemented in teaching a graduate-level course on social research methodology. This paper describes the conceptualization and implementation of the developmentally attuned course, and reports a qualitative study that examined student development as its result. Qualitative data were collected from five cohorts of course participants, in the forms of reflective essays, student interviews, and the instructor’s teaching journal. Seven themes were identified that reflected student development throughout the course. The seven themes fall into three dimensions of epistemological, intrapersonal, and interpersonal development that are interconnected, and the epistemological dimension stands out as a strong partner among the three. These findings may help university faculty understand and integrate student development into their teaching practices.  相似文献   

人工智能时代情报学发展走向之辨——对本体论、感知论、方法论、服务论的再思考     

曹文振  赖纪瑶  王延飞 《情报学报》2020,39(5):557-564

人工智能相关技术的迅猛发展和逐步普及,使得情报学难以避免人工智能的融合趋势,无论这种融合是主动为之或是被动选择。然而学界对人工智能时代情报学学科的发展走向并未予以充分探讨,大部分研究均将焦点置于大数据与下一代互联网环境中进行论述。本研究将人工智能时代情报学学科走向解构为"本体论""感知论""方法论""服务论"四个论题,对每个论题借由理论面向与实践面向的二分法展开阐释,并从整体视角上提出应在人工智能洪流中找准情报学定位,不能忽视"人"在情报学中的价值以及重视跨学科融合、跨领域应用的发展趋势。  相似文献   

《湖南农民运动考察报告》中思想政治教育的方法论意蕴     

王海  段宝玉 《保定学院学报》2020,(2):118-122

《湖南农民运动考察报告》在毛泽东的众多著作中占据极其显著的地位,它不仅包含着丰富的具体理论和内容,也蕴含着深邃的方法论思想。从思想政治教育视角剖析《湖南农民运动考察报告》可以发现其蕴含着丰富的方法论思想,例如调查研究方法、注重群众力量工作方法、具体问题具体分析方法、问题意识以及创新思维的工作方法等等。认真学习和领会这些方法对于今后一个时期做好思想政治教育工作具有重要的方法论借鉴意义。  相似文献   

A study into the impact of the Reading Education Assistance Dogs scheme on reading engagement and motivation to read among Early Years Foundation-Stage children     

Olivia Noble 《Education 3-13》2018,46(3):277-290

This research explores the impact of the Reading Education Assistance Dogs (READ) scheme on reading engagement and motivation among Early Years Foundation-Stage children using a case study approach at a primary school in the English Midlands. There is a notable lack of UK-based research into the READ scheme, which offers a potential alternative method for promoting engagement among young readers. This study used qualitative techniques to determine if the READ scheme is reported to have an impact; and if so, what type of impact. The findings suggest that the READ scheme is successful in a number of areas, including promoting engagement, increased motivation, improved attainment, fostering children’s enjoyment and promoting a love of reading, alongside other additional benefits for specific target groups. It must be recognised that this case study is based on a small pool of opportunity-sampled participants, so the findings cannot be further generalised, but do provide a useful insight into an under-researched area, as a starting point for which more specific aspects and impacts could be investigated.  相似文献   

Contribution of uncertainty in estimation of active drag using assisted towing method in front crawl swimming     

Pendar Hazrati  Peter James Sinclair  Wayne Spratford  René Edouard Ferdinands  Bruce Robert Mason 《Journal of sports sciences》2018,36(1):7-13

Active drag force in swimming can be calculated from a function of five different variables: swim velocity, tow velocity, belt force, power output and exponent of velocity. The accuracy of the drag force value is dependent on the accuracy of each variable, and on the contribution of each variable to drag estimation. To calculate uncertainty in drag value, first the derivatives of the active drag equation with respect to each variable were obtained. Second, these were multiplied by the uncertainty of that variable. Twelve national age and open level swimmers were recruited to complete four free swimming and five active drag trials. The uncertainties for the free and the tow swim velocities, and for the belt force, contributed approximately 5–6% and 2–3% error, respectively, in calculation of drag. The result of the uncertainty of the velocity exponent (1.8–2.6) indicated a contribution of about 6% error in active drag. The contribution of unequal power output showed that if a power changed 7.5% between conditions, it would lead to about 30% error in calculated drag. Consequently, if a swimmer did not maintain constant power output between conditions, there would be substantial errors in the calculation of active drag.  相似文献   

教育效能的本质、特征与改进方法论     

温恒福  温宏宇 《教育学报》2020,(2):66-74

面对推进教育现代化,建设教育强国,办好人民满意教育的时代使命,教育不仅要有高效率和高质量,更要追求高效能。教育效能是教育主体全面有效实现教育目的,保障师生健康幸福与可持续发展的能量与能力。其本质是教育活动合目的有效性整体,主要表现为合目的有效性的程度(深度、广度和持久度)。教育效能具有合目的性、有效性、整体性、持续性、潜在性与时代性等主要特征。教育效能改进的方法论是整体结构优化。主要包括六个方面:以提升"合目的有效整体性"为核心的整体结构优化;在提高素质的基础上完善人格目标;优化教育保健的教育教学生态;创建师生高效能教学共同体的师生关系;学习先进,科学增效、科技赋能、创造性艺术性改进的教育教学方法;在教育效能改进中创造更先进的富有中国特色与时代风格的现代教育文明的品格与态势。  相似文献   

基于CST的战略研究方法论     

钟映竑  杨建梅 《科学学研究》2003,21(1):30-34

评论式系统思考 (CST)以及全面系统干预 (TSI)是系统方法论的新进展。本文在介绍其主要思想的基础上 ,将CST和TSI引入战略方法论的研究 ,为战略研究方法论的综合集成与创新开辟了一条新的思路。  相似文献