Functional interaction between Drosophila olfactory sensory neurons and their support cells

Insects detect volatile chemicals using antennae, which house a vast variety of olfactory sensory neurons (OSNs) that innervate hair-like structures called sensilla where odor detection takes place. In addition to OSNs, the antenna also hosts various support cell types. These include the triad of trichogen, tormogen, and thecogen support cells that lie adjacent to their respective OSNs. The arrangement of OSN supporting cells occurs stereotypically for all sensilla and is widely conserved in evolution. While insect chemosensory neurons have received considerable attention, little is known about the functional significance of the cells that support them. For instance, it remains unknown whether support cells play an active role in odor detection, or only passively contribute to homeostasis, e.g., by maintaining sensillum lymph composition. To investigate the functional interaction between OSNs and support cells, we used optical and electrophysiological approaches in Drosophila. First, we characterized the distribution of various supporting cells using genetic markers. By means of an ex vivo antennal preparation and genetically-encoded Ca(2+) and K(+) indicators, we then studied the activation of these auxiliary cells during odor presentation in adult flies. We observed acute responses and distinct differences in Ca(2+) and K(+) fluxes between support cell types. Finally, we observed alterations in OSN responses upon thecogen cell ablation in mature adults. Upon inducible ablation of thecogen cells, we notice a gain in mechanical responsiveness to mechanical stimulations during single-sensillum recording, but a lack of change to the neuronal resting activity. Taken together, these results demonstrate that support cells play a more active and responsive role during odor processing than previously thought. Our observations thus reveal that support cells functionally interact with OSNs and may be important for the extraordinary ability of insect olfactory systems to dynamically and sensitively discriminate between odors in the turbulent sensory landscape of insect flight

Optimization of insect odorant receptor trafficking and functional expression via transient transfection in HEK293 cells

Insect odorant receptors show a limited functional expression in various heterologous expression systems including insect and mammalian cells. This may be in part due to the absence of key components driving the release of these proteins from the endoplasmic reticulum and directing them to the plasma membrane. In order to mitigate this problem we took advantage of small export signals within the human HCN1 and Rhodopsin that have been shown to promote protein release from the endoplasmic reticulum and the trafficking of post-Golgi vesicles, respectively. Moreover, we designed a new vector based on a bidirectional expression cassette to drive the functional expression of the insect odorant receptor co-receptor (Orco) and an odor-binding odorant receptor, simultaneously. We show that this new method can be used to reliably express insect odorant receptors in HEK293 cells via transient transfection and that is highly suitable for downstream applications using automated and high-throughput imaging platforms

Dopamine drives Drosophila sechellia adaptation to its toxic host

Many insect species are host-obligate specialists. The evolutionary mechanism driving the adaptation of a species to a toxic host is, however, intriguing. We analyzed the tight association of Drosophila sechellia to its sole host, the fruit of Morinda citrifolia, which is toxic to other members of the melanogaster species group. Molecular polymorphisms in the dopamine regulatory protein Catsup cause infertility in D. sechellia due to maternal arrest of oogenesis. In its natural host, the fruit compensates for the impaired maternal dopamine metabolism with the precursor l-DOPA, resuming oogenesis and stimulating egg production. l-DOPA present in morinda additionally increases the size of D. sechellia eggs, what in turn enhances early fitness. We argue that the need of l-DOPA for successful reproduction has driven D. sechellia to become an M. citrifolia obligate specialist. This study illustrates how an insect's dopaminergic system can sustain ecological adaptations by modulating ontogenesis and development. DOI: http://dx.doi.org/10.7554/eLife.03785.00

Phosphorylation via PKC Regulates the Function of the Drosophila Odorant Co-Receptor

Insect odorant receptors (ORs) have a unique design of heterodimers formed by an olfactory receptor protein and the ion channel Orco. Heterologously expressed insect ORs are activated via an ionotropic and a metabotropic pathway that leads to cAMP production and activates the Orco channel. The contribution of metabotropic signaling to the insect odor response remains to be elucidated. Disruption of the Gq protein signaling cascade reduces the odor response (Kain et al., 2008). We investigated this phenomenon in HEK293 cells expressing Drosophila Orco and found that phospholipase C (PLC) inhibition reduced the sensitivity of Orco to cAMP. A similar effect was seen upon inhibition of protein kinase C (PKC), whereas PKC stimulation activated Orco even in the absence of cAMP. Mutation of the five PKC phosphorylation sites in Orco almost completely eliminated sensitivity to cAMP. To test the impact of PKC activity in vivo we combined single sensillum electrophysiological recordings with microinjection of agents affecting PLC and PKC function and observed an altered response of olfactory sensory neurons (OSNs) to odorant stimulation. Injection of the PLC inhibitor U73122 or the PKC inhibitor Gö6976 into sensilla reduced the OSN response to odor pulses. Conversely, injection of the PKC activators OAG, a diacylglycerol analog, or phorbol myristate acetate (PMA) enhanced the odor response. We conclude that metabotropic pathways affecting the phosphorylation state of Orco regulate OR function and thereby shape the OSN odor response

PARTICIPACIÓN DEL ENTORNO FAMILIAR EN LA EDUCACIÓN FORMAL DE JÓVENES DE ENSEÑANZA MEDIA: IDEAS PARA UN CAMBIO

El objetivo del presente ensayo es hacer una revisión de los factores más importantes para la comprensión del acompañamiento de las familias en la vida escolar del joven en la enseñanza media, muchas veces caracterizada por un progresivo alejamiento entre las instituciones de educación formal y otros actores relevantes en el proceso de enseñanza y aprendizaje, identificando los cambios en las relaciones entre generaciones y las trayectorias biográficas paralelas a la enseñanza formal, entre otros elementos útiles para el análisis de nuestro trabajo. Pretende ser una contribución al entendimiento de las dinámicas juveniles y su participación en diversos contextos, dando cuenta de la complejidad de aquellas trayectorias

Associations of Hair Dye and Relaxer Use with Breast Tumor Clinicopathologic Features: Findings from the Women’s Circle of Health Study

Background Building upon our earlier findings of significant associations between hair dye and relaxer use with increased breast cancer risk, we evaluated associations of select characteristics of use with breast tumor clinicopathology. Methods Using multivariable-adjusted models we examined the associations of interest in a case-only study of 2998 women with breast cancer, overall and stratified by race and estrogen receptor (ER) status, addressing multiple comparisons using Bonferroni correction. Results Compared to salon application of permanent hair dye, home kit and combination application (both salon and home kit application) were associated with increased odds of poorly differentiated tumors in the overall sample. This association was consistent among Black (home kit: OR 2.22, 95 % CI: 1.21–5.00; combination: OR 2.46, 95 % CI: 1.21–5.00), but not White women, and among ER+ (home kit: OR 1.47, 95 % CI: 0.82–2.63; combination: OR 2.98, 95 % CI: 1.62–5.49) but not ER-cases. Combination application of relaxers was associated with increased odds of tumors \u3e2.0 cm vs. \u3c1.0 cm (OR = 1.82, 95 % CI: 1.23–2.69). Longer duration and earlier use of relaxers and combination application of permanent hair dyes and relaxers were associated with breast tumor features including higher tumor grade and larger tumor size, which often denote more aggressive phenotypes, although the findings did not maintain significance with Bonferroni correction. Conclusions These novel data support reported associations between hair dye and relaxer use with breast cancer, showing for the first time, associations with breast tumor clinicopathologic features. Improved hair product exposure measurement is essential for fully understanding the impact of these environmental exposure with breast cancer and to guide risk reduction strategies in the future

Autoconcepto académico y toma de decisiones en el alumnado de bachillerato

ABSTRACTThis article shows the relationship between academic self‐concept, perceived academic self‐concept, and decision making in Secondary Education. 454 students take part in this research. The instrument used in this article was a questionnaire containing an adaptation “Self‐Concept of Ability General Scale”, “Perceived Parental Evaluation of Ability Scale” and “Perceived Teacher’s Evaluations of Ability Scale” from Brookover, Erickson y Joiner (1967). The statistical analysis shows high correlations between analysed variables. The students who choose the University: a) they value their academic years; b) they become aware a good impression about their parents and teachers and about their high school achievement; c) they adopt a more responsible attitude towards their future studies, from those who choose another option. The results provide interesting suggestions to generate intervention strategies in the academic and working decision making process.RESUMEN Este trabajo analiza las relaciones entre el autoconcepto académico y el autoconcepto académico percibido con la toma de decisiones de los alumnos de Bachillerato. En la investigación participaron 454 alumnos. El instrumento utilizado fue un cuestionario en el que se incluyó una adaptación para el Bachillerato de las escalas “Qué Opinas de ti Mismo”, “Qué Opinan Tus Padres de Ti” y “Qué Opinan Tus profesores de Ti” de Brookover, Erickson y Joiner (1967). Los análisis estadísticos muestran altas correlaciones entre las variables analizadas. Los alumnos que optan por la Universidad: a) valoran más favorablemente su faceta académica; b) perciben en sus padres y en el profesorado una valoración más positiva de su rendimiento en Bachillerato; c) adoptan una actitud más responsable hacia sus estudios que quienes eligen otra opción. Los resultados aportan interesantes sugerencias para generar estrategias de intervención en los procesos de toma de decisiones académico-laborales. ABSTRACT This article shows the relationship between academic self‐concept, perceived academic self‐concept, and decision making in Secondary Education. 454 students take part in this research. The instrument used in this article was a questionnaire containing an adaptation “Self‐Concept of Ability General Scale”, “Perceived Parental Evaluation of Ability Scale” and “Perceived Teacher’s Evaluations of Ability Scale” from Brookover, Erickson y Joiner (1967). The statistical analysis shows high correlations between analysed variables. The students who choose the University: a) they value their academic years; b) they become aware a good impression about their parents and teachers and about their high school achievement; c) they adopt a more responsible attitude towards their future studies, from those who choose another option. The results provide interesting suggestions to generate intervention strategies in the academic and working decision making process