Models of classroom assessment for course-based research experiences

Course-based research pedagogy involves positioning students as contributors to authentic research projects as part of an engaging educational experience that promotes their learning and persistence in science. To develop a model for assessing and grading students engaged in this type of learning experience, the assessment aims and practices of a community of experienced course-based research instructors were collected and analyzed. This approach defines four aims of course-based research assessment—(1) Assessing Laboratory Work and Scientific Thinking; (2) Evaluating Mastery of Concepts, Quantitative Thinking and Skills; (3) Appraising Forms of Scientific Communication; and (4) Metacognition of Learning—along with a set of practices for each aim. These aims and practices of assessment were then integrated with previously developed models of course-based research instruction to reveal an assessment program in which instructors provide extensive feedback to support productive student engagement in research while grading those aspects of research that are necessary for the student to succeed. Assessment conducted in this way delicately balances the need to facilitate students’ ongoing research with the requirement of a final grade without undercutting the important aims of a CRE education

Microtubule-associated protein 1b is required for shaping the neural tube

International audienceAbstractBackgroundShaping of the neural tube, the precursor of the brain and spinal cord, involves narrowing and elongation of the neural tissue, concomitantly with other morphogenetic changes that contribue to this process. In zebrafish, medial displacement of neural cells (neural convergence or NC), which drives the infolding and narrowing of the neural ectoderm, is mediated by polarized migration and cell elongation towards the dorsal midline. Failure to undergo proper NC results in severe neural tube defects, yet the molecular underpinnings of this process remain poorly understood.ResultsWe investigated here the role of the microtubule (MT) cytoskeleton in mediating NC in zebrafish embryos using the MT destabilizing and hyperstabilizing drugs nocodazole and paclitaxel respectively. We found that MTs undergo major changes in organization and stability during neurulation and are required for the timely completion of NC by promoting cell elongation and polarity. We next examined the role of Microtubule-associated protein 1B (Map1b), previously shown to promote MT dynamicity in axons. map1b is expressed earlier than previously reported, in the developing neural tube and underlying mesoderm. Loss of Map1b function using morpholinos (MOs) or δMap1b (encoding a truncated Map1b protein product) resulted in delayed NC and duplication of the neural tube, a defect associated with impaired NC. We observed a loss of stable MTs in these embryos that is likely to contribute to the NC defect. Lastly, we found that Map1b mediates cell elongation in a cell autonomous manner and polarized protrusive activity, two cell behaviors that underlie NC and are MT-dependent.ConclusionsTogether, these data highlight the importance of MTs in the early morphogenetic movements that shape the neural tube and reveal a novel role for the MT regulator Map1b in mediating cell elongation and polarized cell movement in neural progenitor cells

Psychologická analýza interkulturních rozdílů a z nich plynoucích konfliktů v oblasti řízení na příkladu česko-rakouské spolupráce

Time lapse imaging of cell behaviors during NC in a nocodazole-treated embryo (high magnification). Time-lapse movie (1 min intervals) of a nocodazole-treated embryo, mosaically expressing mGFP, imaged from a dorsal view, anterior towards the top, beginning approximately at the 2–3 som stage. (MOV 163 kb

Additional file 9: of Microtubule-associated protein 1b is required for shaping the neural tube

Time lapse imaging of NC in a map1b MO1-injected embryo. Time-lapse movie (1 min intervals) of a map1b MO1 (10 ng)-injected embryo mosaically expressing mGFP, imaged from a dorsal view, anterior towards the top, beginning approximately at the 2–3 som stage and extending to the 6–7 som stage. (MOV 538 kb

Additional file 5: Figure S3. of Microtubule-associated protein 1b is required for shaping the neural tube

Efficacy of map1b MOs. (A) Schematic representation of zebrafish map1b, showing map1b MO1 binding site at the exon 4- intron 4 splice junction (red line and lettering), map1b MO2 binding site at the intron 4- exon 5 splice junction (blue line and lettering) and map1b MO3 at the translational start site (green line and lettering). Exons are represented by black boxes with corresponding numbers on top. (B) RT-PCR analysis of the region targeted by splice MOs . The upper (750bp) and lower (300bp) bands correspond to unspliced and spliced product respectively. (C) Quantification of the width of the neural plate (tb- 1 som) of control embryos and embryos injected with map1b MO1 (4 ng), map1b MO3 (10 ng) and map1b MO1 (4 ng) + map1b MO3 (10 ng). * Indicates statistical significance using a Kruskal-Wallis test followed by Dunn’s post-hoc test (P <0.05 compared to the rest of the groups). (D) Side views of 24 hpf uninjected, map1b MO1-injected (10 ng) and map1b MO2-injected (10 ng) embryos. Black line indicates morphological defects in the hindbrain region. Anterior is to the left, dorsal is up. Scale bar: 250 μm. (PDF 4983 kb

Additional file 7: Figure S5. of Microtubule-associated protein 1b is required for shaping the neural tube

Dynamic microtubules appear normal in Map1b-depleted embryos. Hindbrain sections of embryos at the neural keel (4–5 som) stage immunolabeled with anti-tyr-tub (dynamic MTs) in red (a2, b2, c2) anti-β-tub (total MTs) in green (a3, b3, c3). (a1, b1, c1) Red-Green overlay (yellow) with nuclei labeled in blue using DAPI. Boxed areas are shown in higher magnification in (a2-c3). Arrowheads indicate puncta exclusively labeled with anti-tyr-tub. Scale bars: 10 μm. (PDF 9616 kb