Challenging Pre-Service Students\u27 Teaching Perspectives in an Inquiry-Focused Program

Inquiry teaching based on constructivist learning theory has been an emphasis in pre-service education for over a decade. In general, a developmental teaching perspective supports inquiry-based instruction where teachers view learners as constructors of knowledge and teaching as providing questions, problems, and challenges that form a bridge from the learners\u27 prior knowledge to a new, more sophisticated form of reasoning. Since teaching perspectives influence student learning, teacher effectiveness, and teacher attrition, challenging pre-service teachers to overcome experience-based convictions of a transmission perspective is necessary in teacher education. In this study, we examined the teaching perspectives of secondary, pre-service methods students at the midpoint of an inquiry-focused program. Our findings suggest that, despite being introduced to a variety of teaching perspectives, overcoming preconceptions of good teaching and considering a perspective counter to one\u27s disciplinary major presents a dilemma for pre-service teachers

Tradeoff Between Stability and Multispecificity in the Design of Promiscuous Proteins

Natural proteins often partake in several highly specific protein-protein interactions. They are thus subject to multiple opposing forces during evolutionary selection. To be functional, such multispecific proteins need to be stable in complex with each interaction partner, and, at the same time, to maintain affinity toward all partners. How is this multispecificity acquired through natural evolution? To answer this compelling question, we study a prototypical multispecific protein, calmodulin (CaM), which has evolved to interact with hundreds of target proteins. Starting from high-resolution structures of sixteen CaM-target complexes, we employ state-of-the-art computational methods to predict a hundred CaM sequences best suited for interaction with each individual CaM target. Then, we design CaM sequences most compatible with each possible combination of two, three, and all sixteen targets simultaneously, producing almost 70,000 low energy CaM sequences. By comparing these sequences and their energies, we gain insight into how nature has managed to find the compromise between the need for favorable interaction energies and the need for multispecificity. We observe that designing for more partners simultaneously yields CaM sequences that better match natural sequence profiles, thus emphasizing the importance of such strategies in nature. Furthermore, we show that the CaM binding interface can be nicely partitioned into positions that are critical for the affinity of all CaM-target complexes and those that are molded to provide interaction specificity. We reveal several basic categories of sequence-level tradeoffs that enable the compromise necessary for the promiscuity of this protein. We also thoroughly quantify the tradeoff between interaction energetics and multispecificity and find that facilitating seemingly competing interactions requires only a small deviation from optimal energies. We conclude that multispecific proteins have been subjected to a rigorous optimization process that has fine-tuned their sequences for interactions with a precise set of targets, thus conferring their multiple cellular functions

Challenging pre-service students' teaching perspectives in an inquiry-focused program

Inquiry teaching based on constructivist learning theory has been an emphasis in pre-service education for over a decade. In general, a developmental teaching perspective supports inquiry-based instruction where teachers view learners as constructors of knowledge and teaching as providing questions, problems, and challenges that form a bridge from the learners’ prior knowledge to a new, more sophisticated form of reasoning. Since teaching perspectives influence student learning, teacher effectiveness, and teacher attrition, challenging pre-service teachers to overcome experience-based convictions of a transmission perspective is necessary in teacher education. In this study, we examined the teaching perspectives of secondary, pre-service methods students at the midpoint of an inquiry focused program. Our findings suggest that, despite being introduced to a variety of teaching perspectives, overcoming preconceptions of “good teaching” and considering a perspective counter to one’s disciplinary major presents a dilemma for pre-service teachers.final article publishedJournal Articl

Formal lessons improve informal educational experiences: The influence of prior knowledge on student engagement

Educational experiences can be influenced by novel experiences, yet educators often overlook the influence novelty exerts on students. This quasi-experimental study manipulated prior knowledge before a zoo field trip for 210 urban 7th-grade students from 2 schools, 1 comprised mostly of low-socioeconomic status (SES) families and 1 comprised mostly of middle-SES families. Students participated in 1 of 2 preparatory lessons, only 1 of which previewed field trip-related content, thereby increasing prior knowledge for half the students from each school. Prior knowledge significantly increased learner engagement, measured through attentiveness, from both schools, but in different types of behaviors. Students from the low-SES school demonstrated more attentiveness if their preparatory lesson previewed field trip material than if it was unrelated to the field trip. Students from the middle SES school displayed the same level of attentiveness in both conditions (and overall higher than the low-SES students). This study highlights complexities associated with prior knowledge and reveals strategies to help improve engagement levels for students visiting informal learning environments.Journal Articl

Second-Sphere Interactions between the C93–Y157 Cross-Link and the Substrate-Bound Fe Site Influence the O₂ Coupling Efficiency in Mouse Cysteine Dioxygenase

Cysteine dioxygenase (CDO) is a non-heme iron enzyme that catalyzes the O₂-dependent oxidation of l-cysteine (l-Cys) to produce cysteinesulfinic acid (CSA). Adjacent to the Fe site of CDO is a covalently cross-linked cysteine–tyrosine pair (C93–Y157). While several theories have been proposed for the function of the C93–Y157 pair, the role of this post-translational modification remains unclear. In this work, the steady-state kinetics and O₂/CSA coupling efficiency were measured for wild-type CDO and selected active site variants (Y157F, C93A, and H155A) to probe the influence of second-sphere enzyme–substrate interactions on catalysis. In these experiments, it was observed that both <i>k</i>_cat and the O₂/CSA coupling efficiency were highly sensitive to the presence of the C93–Y157 cross-link and its proximity to the substrate carboxylate group. Complementary electron paramagnetic resonance (EPR) experiments were performed to obtain a more detailed understanding of the second-sphere interactions identified in O₂/CSA coupling experiments. Samples of the catalytically inactive substrate-bound Fe^III–CDO species were treated with cyanide, resulting in a low-spin (<i>S</i> = ¹/₂) ternary complex. Remarkably, both the presence of the C93–Y157 pair and interactions with the Cys carboxylate group could be readily identified by perturbations to the rhombic EPR signal. Spectroscopically validated active site quantum mechanics/molecular mechanics and density functional theory computational models are provided to suggest a potential role for Y157 in the positioning of the substrate Cys in the active site and to verify the orientation of the <b>g</b>-tensor relative to the CDO Fe site molecular axis

Portraits of science self-efficacy: Four undergraduate women in a summer research experience

To strengthen the US scientific workforce, we aim to recruit and retain talented students in science, technology, engineering, and math (STEM) fields, to enhance success among students from groups underrepresented in STEM fields, and to diversify the scientific workforce to mirror the US population. Given that opportunities for authentic research may support STEM advancement, we seek to maximize the number of students involved in research. Our Behavioral Research Advancements in Neuroscience (BRAIN) research program tests the hypothesis that a term-based collaborative-learning model not only provides research opportunities for more students, nut also produces outcomes at least as positive as a traditional one-on-one apprenticeship model. We examined scientific research self-efficacy as a critical construct for measuring student outcomes and predicting student progress toward STEM careers. Here we provide descriptive portraits of four women who participated in BRAIN, integrating quantitative survey data with analysis of pre- and post-semistructured interviews. Although selected for different self-efficacy trajectories in the quantitative surveys, all four women described increased self-efficacy in interviews and emphasized mastery experiences as a source of self-efficacy. Two women illustrate one general outcome from the program: women overcame initially lower scientific research self-efficacy, matching self-efficacy among men by mid-program. The overarching study suggests that both team-based research and apprenticeships can raise scientific research self-efficacy, which predicts STEM career success. Therefore, this collaborative model provides a structure for authentic research at institutions that may lack available mentors, and yet aim to improve opportunities for diverse undergraduate groups to pursue STEM careers.Journal Articl