Classroom-Based Research Experiences to Support Underserved STEM Student Success: From Introductory Inquiry to Optogenetics in the Embryonic Chicken.

In order to help overcome barriers to success for undergraduate STEM students from disadvantaged backgrounds, we developed two classroom-based research experiences (REs), Connecting Life (CL) and the Summer Research Institute (SRI). These REs were implemented over a two-year period (2014-2015) for regional community college students as part of the Southern Illinois Bridges to the Baccalaureate (SI Bridges) program. CL and SRI, broadly centered in biomedical sciences research, are designed to be offered in tandem. CL utilizes a guided inquiry approach with microscopy work-stations in experimental cell biology to experientially introduce research while building skills and confidence. CL serves as the gateway experience for the SRI, an intensive summer RE in which scholars engage in authentic research using modern technologies including optogenetics. We piloted the REs in year 1 (9 scholars) and made refinements in year 2 (10 scholars). Participants ("Bridges scholars") were enrolled full-time at one of two regional, rural community colleges, and came on-site to Southern Illinois University at Carbondale (SIUC) for the paid REs. Here we report the development, design and implementation of CL and the SRI, and report improved STEM research-related attitudes and aptitudes as a result of these experiences. Our findings suggest that guided inquiry with increasingly technical authentic research projects in a classroom-based and supportive learning community-style setting is a positive model for the transformation of underserved community college students into confident, motivated scientists with research-ready skills, and is likely translatable to other research novices.

Optogenetic regulation of leg movement in midstage chick embryos through peripheral nerve stimulation.

Numerous disorders that affect proper development, including the structure and function of the nervous system, are associated with altered embryonic movement. Ongoing challenges are to understand in detail how embryonic movement is generated and to understand better the connection between proper movement and normal nervous system function. Controlled manipulation of embryonic limb movement and neuronal activity to assess short- and long-term outcomes can be difficult. Optogenetics is a powerful new approach to modulate neuronal activity in vivo. In this study, we have used an optogenetics approach to activate peripheral motor axons and thus alter leg motility in the embryonic chick. We used electroporation of a transposon-based expression system to produce ChIEF, a channelrhodopsin-2 variant, in the lumbosacral spinal cord of chick embryos. The transposon-based system allows for stable incorporation of transgenes into the genomic DNA of recipient cells. ChIEF protein is detectable within 24 h of electroporation, largely membrane-localized, and found throughout embryonic development in both central and peripheral processes. The optical clarity of thin embryonic tissue allows detailed innervation patterns of ChIEF-containing motor axons to be visualized in the living embryo in ovo, and pulses of blue light delivered to the thigh can elicit stereotyped flexures of the leg when the embryo is at rest. Continuous illumination can disrupt full extension of the leg during spontaneous movements. Therefore, our results establish an optogenetics approach to alter normal peripheral axon function and to probe the role of movement and neuronal activity in sensorimotor development throughout embryogenesis.

Mutations in alpha-tubulin promote basal body maturation and flagellar assembly in the absence of delta-tubulin.

We have isolated suppressors of the deletion allele of delta-tubulin, uni3-1, in the biflagellate green alga Chlamydomonas reinhardtii. The deletion of delta-tubulin produces cells that assemble zero, one or two flagella and have basal bodies composed primarily of doublet rather than triplet microtubules. Flagellar number is completely restored in the suppressed strains. Most of the uni3-1 suppressors map to the TUA2 locus, which encodes alpha2-tubulin. Twelve independent tua2 mutations were sequenced. Amino acids D205 or A208, which are nearly invariant residues in alpha-tubulin, were altered. The tua2 mutations on their own have a second phenotype - they make the cells colchicine supersensitive. Colchicine supersensitivity itself is not needed for suppression and colchicine cannot phenocopy the suppression. The suppressors partially restore the assembly of triplet microtubules. These results suggest that the delta-tubulin plays two roles: it is needed for extension or stability of the triplet microtubule and also for early maturation of basal bodies. We suggest that the mutant alpha-tubulin promotes the early maturation of the basal body in the absence of delta-tubulin, perhaps through interactions with other partners, and this allows assembly of the flagella.