Explorations, Vol. 4, No. 3

Articles include: Cover: Trophy: MooseHorn, from the Trophy Series, by Caellaigh B. Desrosiers. Editorial Reflections, by Carole J. Bombard North Cascade Glacier Climate Project, by Mauri Pelto Stained Glass Molecules, by Anne P. Sherblom Lobsters Inside-Out: A Guide to the Maine Lobster Community Forestry: UMaine Cooperative Extension Service, by Nancy E. Coverstone and William D. Lilley Where Are They Now? — Robert F. LaPrade, M.D. ’81 Little Critters with a Big Job: Ciliated Protozoa and the Gulf of Maine Food Chain, by Marcia Gauvin from a paper by Charles Gregory The Innovation of Tradition: Low-Cost, Low-Input Alternatives for Maine Farmers, by Marcia Gauvin Just What IS An Animal? Preschoolers Investigate Merging Two Cultures: Our Cover Artist, by Caellaigh Bennett Derosiers Freezing and Photosynthesis, by Steven R. Dudgeon, Ian R. Davison, and Robert L. Vada

Chemical and biological investigation of Indigofera ammoxylum (DC.) Polhill. red and white phenotypes through feature-based molecular networking

peer reviewedChemical investigation of ethyl acetate bark extracts of Indigofera ammoxylum red and white phenotypes led to the bio-guided isolation of four previously undescribed flavonoids, named (2S,3R)-3′,7-dihydroxy-4′,6-dimethoxyflavanol (1), (2S,3R)-6-methoxy-7-hydroxyflavanol (2), 2′,3′,7-trihydroxy-4′,6-dimethoxyisoflavone (7) and 2′,5'-dimethoxy-4′,5,7-trihydroxyisoflavanone (8), along with 14 known compounds (3-6 and 9-18). The previously undescribed structures were characterized based on NMR, HRESIMS, UV and IR data. Published spectroscopic data were used to deduce the structure of the known compounds. Eleven of the 18 isolated metabolites were evaluated for anti-inflammatory activity and cytotoxic activity against human liver carcinoma cells and human colon and colorectal adenocarcinoma cells. All tested compounds showed an anti-inflammatory activity (IC 50 NO < 25 μg/mL), and compounds 2 and 3 were more selective than the positive control dexamethasone. Afromorsin (6) showed promising cytotoxic properties against both cancer cell lines (IC 50 18.9 and 11.4 μg/mL). Feature-based molecular networking approach applied to bark and leaves extracts of the two phenotypes allowed to detect bioactive analogues, belonging to the families of flavones, isoflavones, flavanones, flavanols and flavonols, and to explore the chemodiversity of the species. The red and white phenotypes have a similar composition, whereas bark and leaves contain specific chemical entities. Finally, this approach highlighted a cluster of potentially bioactive and undescribed metabolites

Eficiencia simbiótica de rizobios nativos de Sancti Spíritus, Cuba, inoculados en Centrosema molle

Se realizó un ensayo en invernadero, con el objetivo de determinar la eficiencia simbiótica de 39 cepas nativas de bradyrizobios procedentes de Sancti Spíritus. Los aislamientos se hicieron a partir de nódulos radicales de Centrosema molle, Centrosema virginianum y Centrosema plumieri, los cuales son macrosimbiontes provenientes de las zonas centro y sur de Sancti Spíritus. Las cepas obtenidas se inocularon en C. molle, leguminosa forrajera promisoria para la alimentación del ganado en el territorio. Los métodos de inoculación fueron estándares, acorde con lo recomendado en la literatura internacional. El diseño experimental fue de bloques al azar, con 41 tratamientos y tres réplicas. Se realizó análisis de varianza (ANOVA) y se evaluó el peso seco de la parte aérea de la planta, el peso seco radical, el índice de nodulación y el rendimiento de nitrógeno. Se concluye que existió una alta eficiencia simbiótica de las cepas nativas de la zona centro, al ser inoculadas en una leguminosa perteneciente a la misma zona; mientras que las de la zona sur fueron ineficientes en dicha leguminosa. Por otra parte, JK3 (C. virginianum), HG1 (C. plumieri) ambas de la zona centro, SP20 (C. molle, zona sur) y JJ2 (C. virginianum, zona centro) presentaron altos índices de eficiencia en la leguminosa evaluada, lo que las convierte en las más promisorias. Los altos índices de nodulación de JH4, JJ2, JJ7, JK6, JK1 y JK5 (C. virginianum) no implicaron una alta eficiencia simbiótica. Se recomienda una fase de selección en condiciones de campo, con diferentes macrosimbiontes y en condiciones edafoclimáticas estresantes

Efecto de la inoculación con bacterias rizosféricas en dos variedades de trigo. Fase I: condiciones controladas

The experiment was carried out in a greenhouse so that the inoculation, both simple and combined (with the rhizospheric bacteria- Sinorhizobium and Azospirllium), en two varieties of Wheat. Materials and methodologies were used in accordance with previously prescribed conventional methodologies for this study. The experimental design was completely randomized, with 4 replicas and 10 treatments. A statistical analysis using two-way variance was done. Fertilized treatment was applied with NH4NO3 (150 ppm/kg soil). The content of chlorophyll foliage was evaluated, dry air weight, dry root weight, length of stem, and germination. In the event that differences appeared, it was determined through use of the Duncan Test, and the differences between varieties with t-Student. It is concluded that combined inoculation with the strain A2 (Sinorhizobium meliloti) and the strain N7 (Azospirillum zeae) had the greatest positive influence on the chlorophyll content of the plants. On the other hand, there was a great difference between the two varieties of wheat in terms of length of stem, dry air weight, and dry root weight. The results of dry air weight and dry root weight, upon combining the two factors that were studied, highly depended on the varietal characteristics of the plant and on the native population of rhizobacteria. The germination of the plants was not linked to any of the applied factors in the experiment.Se llevo a cabo un experimento bajo condiciones controladas para determinar la respuesta de dos variedades de trigo a la inoculacion simple y combinada realizada con Sinorhizobium y Azospirillum. Se utilizo una cepa de A. zeae, y dos cepas pertenecientes a S. meliloti. Los materiales y metodos aplicados correspondieron a lo descrito en las metodologias prestablecidas en este campo de estudio. Diseno experimental: completamente aleatorizado, con 20 tratamientos y 4 replicas. No se utilizo tratamiento fertilizado. Se evaluaron diferentes variables agronomicas, relacionadas con la arquitectura radical y la biomasa aerea. Analisis de varianza bifactorial. En caso de aparecer diferencias, se aplico analisis de varianza de un factor a la interaccion en primera instancia, o a los factores probados. Diferencias entre medias por LSD de Fisher. Se transformaron datos de conteo de digitos por �ãx. Se calculo correlacion y regresion multiple entre variables. Se concluye que la inoculacion combinada de Sinorhizobium con Azospirillum, asi como la inoculacion simple con Sinorhizobium, resultaron de alta importancia en las alternativas de inoculacion que se realizaron en el experimento. Existio una alta diferenciacion entre las dos variedades de trigo en determinadas variables agronomicas, lo que indica una influencia marcada de las caracteristicas varietales de las plantas. Se observó una fuerte relación estadística entre las variables peso seco aéreo y variables de la raíz para los tratamientos inoculados con A2 y A2+N7, respectivamente

Chemical and biological investigation of Indigofera ammoxylum (DC.) Polhill. red and white phenotypes through feature-based molecular networking

International audienceChemical investigation of ethyl acetate bark extracts of Indigofera ammoxylum red and white phenotypes led to the bio-guided isolation of four previously undescribed flavonoids, named (2S,3R)-3′,7-dihydroxy-4′,6-dimethoxyflavanol (1), (2S,3R)-6-methoxy-7-hydroxyflavanol (2), 2′,3′,7-trihydroxy-4′,6-dimethoxyisoflavone (7) and 2′,5'-dimethoxy-4′,5,7-trihydroxyisoflavanone (8), along with 14 known compounds (3-6 and 9-18). The previously undescribed structures were characterized based on NMR, HRESIMS, UV and IR data. Published spectroscopic data were used to deduce the structure of the known compounds. Eleven of the 18 isolated metabolites were evaluated for anti-inflammatory activity and cytotoxic activity against human liver carcinoma cells and human colon and colorectal adenocarcinoma cells. All tested compounds showed an anti-inflammatory activity (IC 50 NO < 25 μg/mL), and compounds 2 and 3 were more selective than the positive control dexamethasone. Afromorsin (6) showed promising cytotoxic properties against both cancer cell lines (IC 50 18.9 and 11.4 μg/mL). Feature-based molecular networking approach applied to bark and leaves extracts of the two phenotypes allowed to detect bioactive analogues, belonging to the families of flavones, isoflavones, flavanones, flavanols and flavonols, and to explore the chemodiversity of the species. The red and white phenotypes have a similar composition, whereas bark and leaves contain specific chemical entities. Finally, this approach highlighted a cluster of potentially bioactive and undescribed metabolites

Cytotoxic Metabolites from Calophyllum tacamahaca Willd.: Isolation and Detection through Feature-Based Molecular Networking

peer reviewedIsocaloteysmannic acid (1), a new chromanone, was isolated from the leaf extract of the medicinal species Calophyllum tacamahaca Willd. along with 13 known metabolites belonging to the families of biflavonoids (2), xanthones (3–5, 10), coumarins (6–8) and triterpenes (9, 11–14). The structure of the new compound was characterized based on nuclear magnetic resonance (NMR), high-resolution electrospray mass spectrometry (HRESIMS), ultraviolet (UV) and infrared (IR) data. Its absolute configuration was assigned through electronic circular dichroism (ECD) measurements. Compound (1) showed a moderate cytotoxicity against HepG2 and HT29 cell lines, with IC50 values of 19.65 and 25.68 µg/mL, respectively, according to the Red Dye method. Compounds 7, 8 and 10–13 exhibited a potent cytotoxic activity, with IC50 values ranging from 2.44 to 15.38 µg/mL, against one or both cell lines. A feature-based molecular networking (FBMN) approach led to the detection of a large amount of xanthones in the leaves extract, and particularly analogues of the cytotoxic isolated xanthone pyranojacareubin (10)

L’oral aujourd’hui : perspectives didactiques

Il n’est plus temps aujourd’hui de s’interroger sur la légitimité d’un enseignement de l’oral : tous les programmes et plans d’études actuels des différents pays et régions francophones lui donnent une place conséquente, de la maternelle à la fin du secondaire, des premiers rituels langagiers aux genres les plus complexes. Ce nouvel ouvrage de la collection Recherches en didactique du français a dès lors pour principal objectif - et intérêt - de présenter des pistes et réalisations concrètes, fondées didactiquement. Celles-ci témoignent des avancées dans ce domaine, mais aussi du développement d’une ingénierie didactique solidement argumentée, attentive aux démarches d’élaboration et de validation des dispositifs proposés. Au-delà de certaines convergences, les contributions font apparaitre des manières diversifiées d’envisager l’ « oral » comme objet de l’enseignement : des pratiques communicatives larges, multimodales, à des conduites langagières « transversales » telles la justification ou l’argumentation, d’un oral au service de l’écrit à des approches spécifiquement centrées sur des genres oraux tels le débat ou le documentaire, en production ou en compréhension. L’ouvrage aborde ainsi de nombreuses questions, notamment à propos des normes appliquées, ou à appliquer, lorsqu’on enseigne l’oral, de l’évaluation, des relations entre oral et écrit, de la formation, voire de la délimitation même du domaine. Il pointe aussi quelques lacunes qui demeurent, concernant la progression des apprentissages par exemple. Cet ouvrage est de nature à intéresser les enseignant-e-s, qui pourront y trouver diverses pistes, les formateurs et formatrices, les didacticien-ne-s des langues et… tous les adeptes de l’oral, sous toutes ses formes et dans toutes ses variétés