Janet Branchaw

Assessment of Course-Based Undergraduate Research Experiences: A Meeting Report

This report presents a summary of a meeting on assessment of course-based undergraduate research experiences (CUREs), including an operational definition of a CURE, a summary of research on CUREs, relevant findings from studies of undergraduate research internships, and recommendations for future research on and evaluation of CUREs.

Functional Analysis of a Mouse Brain Elk-Type K+Channel

Members of the Ether à go-go (Eag) K+channel subfamilies Eag, Erg, and Elk are widely expressed in the nervous system, but their neural functions in vivoremain largely unknown. The biophysical properties of channels from the Eag and Erg subfamilies have been described, and based on their characteristic features and expression patterns, Erg channels have been associated with native currents in the heart. Little is known about the properties of channels from the Elk subfamily. We have identified a mouse gene, Melk2, that encodes a predicted polypeptide with 48% amino acid identity to Drosophila Elk but only 40 and 36% identity with mouse Erg (Merg) and Eag (Meag), respectively. Melk2 RNA appears to be expressed at high levels only in brain tissue. Functional expression ofMelk2 in Xenopus oocytes reveals large, transient peaks of current at the onset of depolarization. Like Meag currents, Melk2 currents activate relatively quickly, but they lack the nonsuperimposable Cole–Moore shift characteristic of the Eag subfamily. Melk2 currents are insensitive to E-4031, a class III antiarrhythmic compound that blocks the Human Ether-à-go-go-Related Gene (HERG) channel and its counterpart in native tissues, IKr. Melk2 channels exhibit inward rectification because of a fast C-type inactivation mechanism, but the slower rate of inactivation and the faster rate of activation results in less inward rectification than that observed in HERG channels. This characterization of Melk currents should aid in identification of native counterparts to the Elk subfamily of channels in the nervous system.

Entering Research: A Course That Creates Community and Structure for Beginning Undergraduate Researchers in the STEM Disciplines

Undergraduate research experiences have been shown to enhance the educational experience and retention of college students, especially those from underrepresented populations. However, many challenges still exist relative to building community among students navigating large institutions. We developed a novel course called Entering Research that creates a learning community to support beginning undergraduate researchers and is designed to parallel the Entering Mentoring course for graduate students, postdocs, and faculty serving as mentors of undergraduate researchers. The course serves as a model that can be easily adapted for use across the science, technology, engineering, and mathematics (STEM) disciplines using a readily available facilitators manual. Course evaluations and rigorous assessment show that the Entering Research course helps students in many ways, including finding a mentor, understanding their place in a research community, and connecting their research to their course work in the biological and physical sciences. Students in the course reported statistically significant gains in their skills, knowledge, and confidence as researchers compared with a control group of students, who also were engaged in undergraduate research but not enrolled in this course. In addition, the faculty and staff members who served as facilitators of the Entering Research course described their experience as rewarding and one they would recommend to their colleagues.

Defining Attributes and Metrics of Effective Research Mentoring Relationships

Despite evidence of mentoring’s importance in training researchers, studies to date have not yet determined which mentoring relationships have the most impact and what specific factors in those mentoring relationships contribute to key outcomes, such as the commitment to and persistence in research career paths for emerging researchers from diverse populations. Efforts to broaden participation and persistence in biomedical research careers require an understanding of why and how mentoring relationships work and their impact, not only to research training but also to promoting career advancement. This paper proposes core attributes of effective mentoring relationships, as supported by the literature and suggested by theoretical models of academic persistence. In addition, both existing and developing metrics for measuring the effectiveness of these attributes within mentoring relationships across diverse groups are presented, as well as preliminary data on these metrics from the authors’ work.

Membrane Excitability and Secretion from Peptidergic Nerve Terminals

1. Thin slices of the posterior pituitary can be used as a preparation for the study of biophysical mechanisms underlying neuropeptide secretion. Patch-clamp techniques in this preparation have revealed the properties of ion channels that control the excitability of the nerve terminal membrane and have clarified the relation between Ca2+ and exocytosis. 2. Repetitive electrical activity at high frequencies broadens action potentials to allow more Ca2+ entry and thus enhance exocytosis. Action potential broadening results from the inactivation of a voltage-dependent K+ channel. 3. When repetitive electrical activity is sustained, secretion is depressed. This depression can be attributed in part to action potential failure caused by the opening of a Ca(2+)-activated K+ channel. This channel can be modulated by protein kinases, phosphatases, and G-proteins. 4. The inhibitory neurotransmitter GABA activates a GABAA receptor in the nerve terminal membrane. The gating of the associated Cl- channel depolarizes the membrane slightly to inactivate voltage-gated Na+ channels and block action potential propagation. 5. The response of the nerve terminal GABAA receptor is enhanced by neuroactive steroids and this can potentiate the inhibition of neurosecretion by GABA. The action of neurosteroids at this site could play a role in changes in neuropeptide secretion associated with reproductive transitions. 6. Ca2+ channels in the nerve terminal membrane are inactivated by sustained depolarization and by trains of brief pulses. Ca2+ entry promotes Ca2+ channel inactivation during trains by inhibiting the recovery of Ca2+ channels from inactivation. The inactivation of Ca2+ channels can play a role in defining the optimal frequency and train duration for evoking neuropeptide secretion. 7. Measurements of membrane capacitance in peptidergic nerve terminals have revealed rapid exocytosis and endocytosis evoked by Ca2+ entry through voltage-gated Ca2+ channels. Exocytosis is too rapid to account for the delays in neuropeptide secretion evoked by trains of action potentials. Endocytosis sets in rapidly after exocytosis with a time course comparable to that of the rapid endocytosis observed in nerve terminals at rapid synapses. Our results support the finding in rapid synaptic nerve terminals that endocytosis is inhibited by intracellular Ca2+. Multiple pools of vesicles were revealed, and these pools may reflect different stages in the mobilization and release of neuropeptide.

Culturally Diverse Undergraduate Researchers’ Academic Outcomes and Perceptions of Their Research Mentoring Relationships

Few studies have empirically investigated the specific factors in mentoring relationships between undergraduate researchers (mentees) and their mentors in the biological and life sciences that account for mentees’ positive academic and career outcomes. Using archival evaluation data from more than 400 mentees gathered over a multi-year period (2005–2011) from several undergraduate biology research programs at a large, Midwestern research university, we validated existing evaluation measures of the mentored research experience and the mentor–mentee relationship. We used a subset of data from mentees (77% underrepresented racial/ethnic minorities) to test a hypothesized social cognitive career theory model of associations between mentees’ academic outcomes and perceptions of their research mentoring relationships. Results from path analysis indicate that perceived mentor effectiveness indirectly predicted post-baccalaureate outcomes via research self-efficacy beliefs. Findings are discussed with implications for developing new and refining existing tools to measure this impact, programmatic interventions to increase the success of culturally diverse research mentees and future directions for research.

New Measures Assessing Predictors of Academic Persistence for Historically Underrepresented Racial/Ethnic Undergraduates in Science

Using social cognitive career theory and science identity theory, the authors validate new measures assessing persistence-related factors with students from historically underrepresented racial/ethnic groups in science.

Conceptual Elements: A Detailed Framework to Support and Assess Student Learning of Biology Core Concepts.

The authors break down the Vision and Change core concepts into elements that transcend biological subdisciplines and scales in a new learning framework. The Conceptual Elements Framework can be used to guide the development of core concept learning outcomes, instructional materials, and assessments of student learning.

Exploring Biology: A "Vision and Change" Disciplinary First-Year Seminar Improves Academic Performance in Introductory Biology.

The transition to college is challenging for most students, especially those who aspire to major in the science, technology, engineering, or mathematics disciplines, in which introductory courses can be large and instruction less than optimal. This paper describes a novel, disciplinary first-year seminar (FYS) course, Exploring Biology, designed to address many of the challenges facing aspiring biology students beginning their academic careers at a large public research university. The course addresses typical FYS goals, such as community building, introduction to resources, and academic skill development, and introduces students to the core concepts of biology defined in the 2011 Vision and Change report. Relative to a matched comparison group of students, Exploring Biology alumni were retained at higher rates and had higher levels of academic performance in a subsequent introductory biology course, suggesting Exploring Biology has a positive impact on future academic performance in the discipline. Results from course evaluations and an alumni survey show that, overall, students valued both the FYS components and biology components of the course. These results provide evidence that the Exploring Biology disciplinary FYS model is an intervention that may increase academic success and retention in biology.