Hands-on immunology: Engaging learners of all ages through tactile teaching tools.

Ensuring the public has a fundamental understanding of human-microbe interactions, immune responses, and vaccines is a critical challenge in the midst of a pandemic. These topics are commonly taught in undergraduate- and graduate-level microbiology and immunology courses; however, creating engaging methods of teaching these complex concepts to students of all ages is necessary to keep younger students interested when science seems hard. Building on the Tactile Teaching Tools with Guided Inquiry Learning (TTT-GIL) method we used to create an interactive lac operon molecular puzzle, we report here two TTT-GIL activities designed to engage diverse learners from middle schoolers to masters students in exploring molecular interactions within the immune system. By pairing physical models with structured activities built on the constructivist framework of Process-Oriented Guided Inquiry Learning (POGIL), TTT-GIL activities guide learners through their interaction with the model, using the Learning Cycle to facilitate construction of new concepts. Moreover, TTT-GIL activities are designed utilizing Universal Design for Learning (UDL) principles to include all learners through multiple means of engagement, representation, and action. The TTT-GIL activities reported here include a web-enhanced activity designed to teach concepts related to antibody-epitope binding and specificity to deaf and hard-of-hearing middle and high school students in a remote setting and a team-based activity that simulates the evolution of the Major Histocompatibility Complex (MHC) haplotype of a population exposed to pathogens. These activities incorporate TTT-GIL to engage learners in the exploration of fundamental immunology concepts and can be adapted for use with learners of different levels and educational backgrounds.

Sugar-seeking insects as a source of diverse bread-making yeasts with enhanced attributes.

Insects represent a particularly interesting habitat in which to search for novel yeasts of value to industry. Insect-associated yeasts have the potential to have traits relevant to modern food and beverage production due to insect-yeast interactions, with such traits including diverse carbohydrate metabolisms, high sugar tolerance, and general stress tolerance. Here, we consider the potential value of insect-associated yeasts in the specific context of baking. We isolated 63 yeast strains from 13 species of hymenoptera from the United States, representing 37 yeast species from 14 genera. Screening for the ability to ferment maltose, a sugar important for bread production, resulted in the identification of 13 strains of Candida, Lachancea, and Pichia species. We assessed their ability to leaven dough. All strains produced baked loaves comparable to a commercial baking strain of Saccharomyces cerevisiae. The same 13 strains were also grown under various sugar and salt conditions relevant to osmotic challenges experienced in the manufacturing processes and the production of sweet dough. We show that many of these yeast strains, most notably strains of Lachancea species, grow at a similar or higher rate and population size as commercial baker's yeast. We additionally assessed the comparative phenotypes and genetics of insect-associated S. cerevisiae strains unable to ferment maltose and identified baking-relevant traits, including variations in the HOG1 signaling pathway and diverse carbohydrate metabolisms. Our results suggest that non-conventional yeasts have high potential for baking and, more generally, showcase the success of bioprospecting in insects for identifying yeasts relevant for industrial uses.

Using Metabolic Engineering to Connect Molecular Biology Techniques to Societal Challenges.

Genetically modified organisms (GMOs) are a topic of broad interest and are discussed in classes ranging from introductory biology to bioethics to more advanced methods-focused molecular biology courses. In most cases, GMOs are discussed in the context of introducing a single protein-coding gene to produce a single desired trait in a crop. For example, a commercially available kit allows students to test whether food products contain GMOs by detecting the Bacillus thuringiensis delta-endotoxin gene, which confers resistance to European corn borers. We have developed an 8-week laboratory module for upper-division undergraduates and graduate students that builds upon students' basic understanding of GMOs to introduce them to the techniques used to sustainably produce commercially valuable products in yeast through metabolic engineering. In this course, students use recombination-based methods to assemble genes encoding entire metabolic pathways in Saccharomyces cerevisiae, perform genetic screens to identify yeast genes that impact metabolite yield, and use error-prone PCR to optimize metabolic pathway function. In parallel to these laboratory-based activities, students engage with the societal impact of these approaches through case studies of products made via yeast metabolic engineering, such as opioids, omega-3 fatty acids, and the Impossible Burger. In this report, we focus on these case studies as well as an individual sustainability project assignment created for this course. This assignment, which spans the 8-week module, asks students to find examples of yeast metabolic engineering that could be used to address current sustainability challenges in their communities. By the end of the course, students synthesize this information to create a case study that could be used to teach concepts related to metabolic engineering and sustainability to their peers. Student approaches to this project have varied from literature reviews, to news searches, to directly contacting and interviewing researchers using novel metabolic engineering approaches. These student-produced projects are used as case studies in future semesters, amplifying student voices and contributing to student ownership. While developed in the context of this course, the sustainability project and case studies are broadly applicable and could be adapted for use in biology or bioethics courses at the undergraduate or graduate level. Through this report, we hope to gain collaborators interested in implementing a version of the course at their institutions, allowing for robust assessment of the impact of the course on a larger group of students.

Building the lac Operon: A Guided-Inquiry Activity Using 3D-Printed Models.

Undergraduate biology courses rely heavily on visual representation of information. Students view images of plants, animals, and microbes, interpret data presented in graphs, and use drawings to understand how cells and molecules interact in three dimensions. Traditional teaching approaches exclude students with visual impairments and disadvantage students with disabilities that affect their interpretation and processing of visual and spatial information, and also students who simply do not identify as "visual learners." By using new technologies to develop tactile teaching tools (TTTs) that can be employed in classrooms, we aim to create inclusive learning environments and more effectively instruct diverse learners. The advent of affordable and accessible 3D printing technology makes it possible to create tactile models that represent molecules, cells, and entire organisms more accurately than traditional visual representations. We describe the assessment of a 3D gene expression puzzle as a guided inquiry learning activity in which students must correctly assemble a series of components in order to achieve an output. Upon completion of the puzzle, the TTT provides tactile feedback through vibration to signal transcriptional activation. Analysis of pre- and postassessment performance demonstrated statistically significant increases in individual students' paired assessment scores in two different classroom implementations, with a greater effect size at a rural minority-serving institution than an urban R1 university. These encouraging preliminary data suggest that TTTs with guided-inquiry learning disproportionately benefit disadvantaged student populations and could serve as a tool in leveling the playing field when teaching abstract biological concepts in diverse educational settings.

STEM BUILD: An Online Community To Decrease Barriers to Implementation of Inclusive Tactile Teaching Tools.

Access to 3D printing and other "maker" technologies has opened new doors for the creation of classroom activities using physical models. Multiple strategies for implementing 3D-printed models exist, and work to define best practices is ongoing. We outline the strengths and weaknesses of common strategies for employing physical models in undergraduate biology courses and describe a novel strategy that we have developed to pair 3D-printed models with guided inquiry learning to create inclusive and interactive learning experiences. We further introduce the STEM BUILD website, a resource that we have developed to facilitate collaboration among instructors, makers, researchers, and Universal Design for Learning experts and reduce barriers to broad implementation of inclusive kinesthetic learning activities.

Systematic analysis of F-box proteins reveals a new branch of the yeast mating pathway.

The mating pathway in yeast Saccharomyces cerevisiae has long been used to reveal new mechanisms of signal transduction. The pathway comprises a pheromone receptor, a heterotrimeric G protein, and intracellular effectors of morphogenesis and transcription. Polarized cell growth, in the direction of a potential mating partner, is accomplished by the G-protein ßγ subunits and the small G-protein Cdc42. Transcription induction, needed for cell-cell fusion, is mediated by Gßγ and the mitogen-activated protein kinase (MAPK) scaffold protein Ste5. A potential third pathway is initiated by the G-protein α subunit Gpa1. Gpa1 signaling was shown previously to involve the F-box adaptor protein Dia2 and an endosomal effector protein, the phosphatidylinositol 3-kinase Vps34. Vps34 is also required for proper vacuolar sorting and autophagy. Here, using a panel of reporter assays, we demonstrate that mating pheromone stimulates vacuolar targeting of a cytoplasmic reporter protein and that this process depends on Vps34. Through a systematic analysis of F-box deletion mutants, we show that Dia2 is required to sustain pheromone-induced vacuolar targeting. We also found that other F-box proteins selectively regulate morphogenesis (Ydr306, renamed Pfu1) and transcription (Ucc1). These findings point to the existence of a new and distinct branch of the pheromone-signaling pathway, one that likely leads to vacuolar engulfment of cytoplasmic proteins and recycling of cellular contents in preparation for mating.