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Ensuring undergraduate students become proficient in relating protein structure to biological function has important implications. With current two-dimensional (2D) methods of teaching, students frequently develop misconceptions, including that proteins contain a lot of empty space, that bond angles for different amino acids can rotate equally, and that product inhibition is equivalent to allostery. To help students translate 2D images to 3D molecules and assign biochemical meaning to physical structures, we designed three 3D learning modules consisting of interactive activities with 3D printed models for amino acids, proteins, and allosteric regulation with coordinating pre- and post-assessments. Module implementation resulted in normalized learning gains on module-based assessments of 30% compared to 17% in a no-module course and normalized learning gains on a comprehensive assessment of 19% compared to 3% in a no-module course. This suggests that interacting with these modules helps students develop an improved ability to visualize and retain molecular structure and function.

Understanding the relationship between molecular structure and function represents an important goal of undergraduate life sciences. Although evidence suggests that handling physical models supports gains in student understanding of structure-function relationships, such models have not been widely implemented in biochemistry classrooms. Three-dimensional (3D) printing represents an emerging cost-effective means of producing molecular models to help students investigate structure-function concepts. We developed three interactive learning modules with dynamic 3D printed models to help biochemistry students visualize biomolecular structures and address particular misconceptions. These modules targeted specific learning objectives related to DNA and RNA structure, transcription factor-DNA interactions, and DNA supercoiling dynamics. We also designed accompanying assessments to gauge student learning. Students responded favorably to the modules and showed normalized learning gains of 49% with respect to their ability to understand and relate molecular structures to biochemical functions. By incorporating accurate 3D printed structures, these modules represent a novel advance in instructional design for biomolecular visualization. We provide instructors with the materials necessary to incorporate each module in the classroom, including instructions for acquiring and distributing the models, activities, and assessments. © 2019 International Union of Biochemistry and Molecular Biology, 47(3):303-317, 2019.

Understanding metabolic function requires knowledge of the dynamics, interdependence, and regulation of metabolic networks. However, multiple professional societies have recognized that most undergraduate biochemistry students acquire only a surface-level understanding of metabolism. We hypothesized that guiding students through interactive computer simulations of metabolic systems would increase their ability to recognize how individual interactions between components affect the behavior of a system under different conditions. The computer simulations were designed with an interactive activity (i.e., module) that used the predict-observe-explain model of instruction to guide students through a process in which they iteratively predict outcomes, test their predictions, modify the interactions of the system, and then retest the outcomes. We found that biochemistry students using modules performed better on metabolism questions compared with students who did not use the modules. The average learning gain was 8% with modules and 0% without modules, a small to medium effect size. We also confirmed that the modules did not create or reinforce a gender bias. Our modules provide instructors with a dynamic, systems-driven approach to help students learn about metabolic regulation and equip students with important cognitive skills, such as interpreting and analyzing simulation results, and technical skills, such as building and simulating computer-based models.

Understanding metabolic function requires knowledge of the dynamics, interdependence, and regulation of biochemical networks. However, current approaches are not optimal to develop the needed mechanistic understanding, and misconceptions about biological processes persist even after graduation. To address these issues, we developed a computational modeling and simulation approach that employs scaffolded learning to teach biochemistry students about the regulation of metabolism. The power of the approach lies in students’ abilities to alter any component or connection in a modeled system and instantly observe the effects of their changes. We find that students who use our approach perform better on biochemistry metabolism questions compared to students in a course that did not use this approach. We also investigated performance by gender and found that our modules may have the potential to increase equity in education. We noted that students are generally positive about the approach and appreciate its benefits. Our modules provide life science instructors with a dynamic and systems-driven approach to teach metabolic regulation and control that improves learning and also equips students with important technical skills.

We describe a new method for the rapid diagnosis of Clostridium difficile infection, with stool sample preparation and DNA extraction by heat and physical disruption in a single-use lysis microreactor (LMR), followed by a rapid PCR amplification step. All steps can be accomplished in

Recently a theoretical analysis of PCR efficiency has been published by Booth et al. (2010). The PCR yield is the product of three efficiencies: (i) the annealing efficiency is the fraction of templates that form binary complexes with primers during annealing, (ii) the polymerase binding efficiency is the fraction of binary complexes that bind to polymerase to form ternary complexes and (iii) the elongation efficiency is the fraction of ternary complexes that extend fully. Yield is controlled by the smallest of the three efficiencies and control could shift from one type of efficiency to another over the course of a PCR experiment. Experiments have been designed that are specifically controlled by each one of the efficiencies and the results are consistent with the mathematical model. The experimental data has also been used to quantify six key parameters of the theoretical model. An important application of the fully characterized model is to calculate initial template concentration from real-time PCR data. Given the PCR protocol, the midpoint cycle number (where the template concentration is half that of the final concentration) can be theoretically determined and graphed for a variety of initial DNA concentrations. Real-time results can be used to calculate the midpoint cycle number and consequently the initial DNA concentration, using this graph. The application becomes particularly simple if a conservative PCR protocol is followed where only the annealing efficiency is controlling.

The polymerase chain reaction (PCR) has found wide application in biochemistry and molecular biology such as gene expression studies, mutation detection, forensic analysis and pathogen detection. Increasingly, quantitative real time PCR is used to assess copy numbers from overall yield. In this study the yield is analyzed as a function of several processes: (1) thermal damage of the template and polymerase occurring during the denaturing step, (2) competition existing between primers and templates to either anneal or form dsDNA, (3) polymerase binding to annealed products (primer/ ssDNA) to form ternary complexes and (4) extension of ternary complexes. Explicit expressions are provided for the efficiency of each process, therefore reaction conditions can be directly linked to the overall yield. Examples are provided where different processes play the yield-limiting role. The analysis will give researchers a unique understanding of the factors that control the reaction and will aid in the interpretation of experimental results.

We describe a new method for the rapid diagnosis of Clostridium difficile infection, with stool sample preparation and DNA extraction by heat and physical disruption in a single-use lysis microreactor (LMR), followed by a rapid PCR amplification step. All steps can be accomplished in20 minutes overall. Gel electrophoresis is currently used to detect the amplification product, pending real-time availability with an ultra-rapid thermocycler. Compared with the dual enzyme immunoassay (EIA) screening test (C. diff Quik Chek Complete; Techlab, Blacksburg, VA), the novel LMR/PCR assay showed complete concordance with all glutamate dehydrogenase (GDH) results (GDH(+)/toxin(+), n = 48; GDH(-)/toxin(-), n = 81). All 69 stool samples with discordant EIA results (GDH(+)/toxin(-)) were tested by both the LMR/PCR assay and the loop-mediated isothermal amplification test (LAMP) (Illumigene C. difficile; Meridian Bioscience, Cincinnati, OH). In 64/69 EIA-discordant samples, LAMP and LMR/PCR results matched (both positive in 29 sample and both negative in 35 samples); in the remaining 5 samples, results were discrepant between the LAMP assay (all five negative) and the LMR/PCR assay (all 5 positive). Overall, LMR/PCR testing matched the current algorithm of EIA and/or LAMP reflex testing in 193/198 (97.5%) samples. The present proof-of-concept study suggests that the novel LMR/PCR technique described here may be developed as an inexpensive, rapid, and reliable point-of-care diagnostic test for C. difficile infection and other infectious diseases.