Connecting Ethical Reasoning to Global Challenges through Analysis of Argumentation.

Scientific literacy is built on critical thinking. The postbaccalaureate workforce enhances our economies and societies by contributing a wealth of knowledge and skill sets to local communities, respective industries, and beyond as our world becomes increasingly interconnected. Education in scientific literacy should teach students how to learn about science and how to cultivate and communicate a positive attitude about science. Learners in a 200-level nonmajors biotechnology course engaged with a series of ethical dilemmas after mastering the basic elements of argument structure and advanced tools in argument evaluation. To introduce collaboration as a constructive process in undergraduate education, student interactions with peers require guidance, flexibility, and compassion to learn from each other. Students gain critical thinking mastery from two modules addressing how we argue and evaluate claims. Students apply these critical thinking skills to various ethical arguments involving responsible conduct of research training. Using our structured and interdisciplinary approach, new scholars learn through practice how to read, analyze, and evaluate research scenarios and respond to potential ethical situations. This strategy allows students to develop important scholarly skills, including a systematic approach to evaluating credibility and applying generosity to theirs and others' understanding of their circumstances.

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.

A multi-level response to DNA damage induced by aluminium.

Aluminium (Al) ions are one of the primary growth-limiting factors for plants on acid soils, globally restricting agriculture. Despite its impact, little is known about Al action in planta. Earlier work has indicated that, among other effects, Al induces DNA damage. However, the loss of major DNA damage response regulators, such SOG1, partially suppressed the growth reduction in plants seen on Al-containing media. This raised the question whether Al actually causes DNA damage and, if so, how. Here, we provide cytological and genetic data corroborating that exposure to Al leads to DNA double-strand breaks. We find that the Al-induced damage specifically involves homology-dependent (HR) recombination repair. Using an Al toxicity assay that delivers higher Al concentrations than used in previous tests, we find that sog1 mutants become highly sensitive to Al. This indicates a multi-level response to Al-induced DNA damage in plants.

SUV2, which encodes an ATR-related cell cycle checkpoint and putative plant ATRIP, is required for aluminium-dependent root growth inhibition in Arabidopsis.

A suppressor mutagenesis screen was conducted in order to identify second site mutations that could reverse the extreme hypersensitivity to aluminium (Al) seen for the Arabidopsis mutant, als3-1. From this screen, it was found that a loss-of-function mutation in the previously described SUV2 (SENSITIVE TO UV 2), which encodes a putative plant ATRIP homologue that is a component of the ATR-dependent cell checkpoint response, reversed the als3-1 phenotype. This included prevention of hallmarks associated with als3-1 including Al-dependent terminal differentiation of the root tip and transition to endoreduplication. From this analysis, SUV2 was determined to be required for halting cell cycle progression and triggering loss of the quiescent centre (QC) following exposure to Al. In conjunction with this, SUV2 was found to have a similar role as ATR, ALT2 and SOG1 in Al-dependent stoppage of root growth, all of which are required for promotion of expression of a suite of genes that likely are part of an Al-dependent DNA damage transcriptional response. This work argues that these Al response factors work together to detect Al-dependent damage and subsequently activate a DNA damage response pathway that halts the cell cycle and subsequently promotes QC differentiation and entrance into endocycling.

Aluminum-Dependent Terminal Differentiation of the Arabidopsis Root Tip Is Mediated through an ATR-, ALT2-, and SOG1-Regulated Transcriptional Response.

By screening for suppressors of the aluminum (Al) hypersensitive Arabidopsis thaliana mutant als3-1, it was found that mutational loss of the Arabidopsis DNA damage response transcription factor SUPPRESSOR OF GAMMA RESPONSE1 (SOG1) confers increased Al tolerance similar to the loss-of-function mutants for the cell cycle checkpoint genes ATAXIA TELANGIECTASIA AND RAD3 RELATED (ATR) and ALUMINUM TOLERANT2 (ALT2). This suggests that Al-dependent terminal differentiation of the root tip is an active process resulting from activation of the DNA damage checkpoint by an ATR-regulated pathway, which functions at least in part through SOG1. Consistent with this, ATR can phosphorylate SOG1 in vitro. Analysis of SOG1's role in Al-dependent root growth inhibition shows that sog1-7 prevents Al-dependent quiescent center differentiation and endoreduplication in the primary root tip. Following Al exposure, SOG1 increases expression of several genes previously associated with DNA damage, including BRCA1 and PARP2, with gel-shift analysis showing that SOG1 can physically associate with the BRCA1 promoter in vitro. Al-responsive expression of these SOG1-regulated genes requires ATR and ALT2, but not ATAXIA TELANGIECTASIA MUTATED, thus demonstrating that in response to chronic Al exposure, ATR, ALT2, and SOG1 function together to halt root growth and promote terminal differentiation at least in part in a transcription-dependent manner.

The Arabidopsis cell cycle checkpoint regulators TANMEI/ALT2 and ATR mediate the active process of aluminum-dependent root growth inhibition.

Aluminum (Al) toxicity is a global issue that severely limits root growth in acidic soils. Isolation of suppressors of the Arabidopsis thaliana Al-hypersensitive mutant, als3-1, resulted in identification of a cell cycle checkpoint factor, ALUMINUM TOLERANT2 (ALT2), which monitors and responds to DNA damage. ALT2 is required for active stoppage of root growth after Al exposure, because alt2 loss-of-function mutants fail to halt root growth after Al exposure, do not accumulate CyclinB1;1 in the root tip, and fail to force differentiation of the quiescent center. Thus, alt2-1 mutants are highly tolerant of Al levels that are severely inhibitory to the wild type. The alt2-1 allele is a loss-of-function mutation in a protein containing a putative DDB1-binding WD40 motif, previously identified as TANMEI, which is required for assessment of DNA integrity, including monitoring of DNA crosslinks. alt2-1 and atr loss-of-function mutants, the latter of which affects the cell cycle checkpoint ATAXIA TELANGIECTASIA-MUTATED AND RAD3-RELATED, are severely sensitive to DNA crosslinking agents and have increased Al tolerance. These results suggest that Al likely acts as a DNA-damaging agent in vivo and that Al-dependent root growth inhibition, in part, arises from detection of and response to this damage by TANMEI/ALT2 and ATR, both of which actively halt cell cycle progression and force differentiation of the quiescent center.