Microtubule polarity determines the lineage of embryonic neural precursor in zebrafish spinal cord.

The phenomenal diversity of neuronal types in the central nervous system is achieved in part by the asymmetric division of neural precursors. In zebrafish neural precursors, asymmetric dispatch of Sara endosomes (with its Notch signaling cargo) functions as fate determinant which mediates asymmetric division. Here, we found two distinct pools of neural precursors based on Sara endosome inheritance and spindle-microtubule enrichment. Symmetric or asymmetric levels of spindle-microtubules drive differently Sara endosomes inheritance and predict neural precursor lineage. We uncover that CAMSAP2a/CAMSAP3a and KIF16Ba govern microtubule asymmetry and endosome motility, unveiling the heterogeneity of neural precursors. Using a plethora of physical and cell biological assays, we determined the physical parameters and molecular mechanisms behind microtubule asymmetries and biased endosome motility. Evolutionarily, the values of those parameters explain why all sensory organ precursor cells are asymmetric in flies while, in zebrafish spinal cord, two populations of neural precursors (symmetric vs asymmetric) are possible.

The Impact of Treating Bilingual Clients on Speech-Language Pathology Students' Cultural Responsiveness.

PURPOSE: Graduate programs often use practicum experience with clients from nonmajority cultures to improve students' cultural responsiveness. Yet, it is not clear whether simply working with a client from a nonmajority culture actually confers this benefit or whether students are thinking about how to include culturally responsive behaviors when they are considering how to address a clinical case. METHOD: Twenty first-year speech-language pathology graduate students (10 Spanish-English bilinguals, 10 monolingual English speakers) were split into three groups: monolingual experimental (n = 4), bilingual experimental (n = 4), and control (n = 12). The experimental groups completed a structured practicum with bilingual Hispanic/Latino clients. They received a 1-hr training in cultural responsiveness and then implemented a systematic language intervention in English or Spanish. Changes to cultural responsiveness were measured via think-aloud cases, and changes to confidence were measured with published, self-report scales. Reflective journal entries revealed what aspects of the clinical practicum students found most salient. RESULTS: Experience working with bilingual clients did not have a substantial effect on students' confidence in their cultural competence. No substantial change was found in cultural responsiveness on the think-aloud for any group. Cultural responsiveness did not appear to be top-of-mind for the students. CONCLUSIONS: Simply working with clients from nonmajority cultures does not create a scenario where cultural responsiveness is likely to improve. Additional targeted, purposeful training in cultural responsiveness is necessary.