Efecto de la biofertilización y los biorreguladores en la germinación y el crecimiento de carica papaya l.

Título en inglés: Effect of biofertilization and bioregulators on germination and growth of Carica papaya L. Resumen Con el objetivo de incrementar y acelerar el proceso de germinación de las semillas y obtener una alta producción y homogeneidad de plántulas de Carica papaya variedad Maradol en vivero, se evaluó el efecto de tres biofertilizantes aplicados solos o en combinación (Azotobacter chroococcum, Azospirillum brasilense y Glomus intraradices), y un biorregulador del crecimiento vegetal, el ácido giberélico (AG3), en la germinación y el crecimiento vegetal. Se realizó un experimento bajo un diseño completamente al azar con ocho tratamientos y tres repeticiones. A las semillas se les aplicó un pretratamiento germinativo con alternancia de temperatura para superar la dormancia. Los tratamientos simples con A. chroococcum y A. brasilense, incrementaron el porcentaje de germinación a 90,28 y 88,89% respectivamente. Además, con la aplicación de los biofertilizantes y el AG3, la velocidad de germinación se incrementó y el tiempo medio de germinación se redujo. La doble aplicación en semillas y foliar de los biofertilizantes y el AG3 en plántulas mejoró el crecimiento vegetal. La población de A. chroococcum fue mayor cuando se inoculó en combinación con G. intraradices. La prevalencia de colonización de las plántulas inoculadas con G. intraradices varió de 18,53 a 26,67%, con el mayor valor registrado para el tratamiento combinado con A. brasilense. Finalmente, aplicando esta metodología se logró acelerar la germinación, obteniéndose una mayor homogeneidad en la emergencia de las plántulas, disminuyendo así el tiempo de permanencia en el vivero. Palabras clave: Azospirillum brasilense; Azotobacter chroococcum; Glomus intraradices; ácido giberélico; dormancia. Abstract In order to increase and accelerate the process of seed germination and obtain a high yield and homogeneity of papaya seedlings cv. Maradol in nurseries, we evaluated the effect of three biofertilizers applied single or in combination (Azotobacter chroococcum, Azospirillum brasilense and Glomus intraradices) and a plant growth bioregulator, the gibberellic acid 3 (AG3), on the germination and subsequent growth of papaya seedlings. An experimental design completely random with eight treatments and three replications were used. The application of a pre-germinal treatment with alternating temperature had to be applied to seeds to overcome dormancy. Single biofertilization with A. chroococcum and A. brasilense, promoted the germination percentage 90.28 y 88.89% respectively. Germination rate could be enhanced and the mean germination time was reduced with the application of biofertilizer and AG3. Both applications on seeds and leaves of biofertilizers and AG3, had a positive effect on plant growth. The population of A. chroococcum was higher in the combined inoculation with G. intraradices. The prevalence of colonization of plants inoculated with G. intraradices ranged from 18.53 to 26.67%, with the greatest values recorded for the treatment involving combined inoculation with A. brasilense. Finally, with the application of this methodology the seed germination rate was improved, as well as the uniformity of seedlings emergence. Key words: Azospirillum brasilense; Azotobacter chroococcum; Glomus intraradices; gibberellic acid; dormancy

Diversidad de hongos micorrícicos arbusculares en maíz con cultivo de cobertura y biofertilizantes en Chiapas, México

The present work was conducted with the objective of know the density, abundance and diversity of arbuscular mycorrhizalfungi (AMF) associated with maize (Zea mays L.) in plots that have been managed with low incomes of external inputsgreen manure/cover crop (AVCC) and biofertilizers. The work was conducted in seven farmer plots with maize crop, ofwhich three have been managed with nescafe bean (Mucuna deeringiana Merr.) as AVCC and four without such antecedentof managing. In each plot were established four treatments of biofertilization: 1) inoculation with AMF, 2) foliar applicationof organic fertilizer, 3) mycorrhizal inoculation with foliar organic fertilizer, and 4) control, which were ordered under arandomized complete block design with seven replications. In total we identified 23 morphospecies, 14 of which werecarried at level of species, being Glomus and Acaulospora the dominant genera. The number of species in plots with AVCCwas 50% higher than without AVCC. In the plots with AVCC was found 91.3% of morphospecies of AMF, while in plotswithout AVCC the 60.9%. The percentage of mycorrhizal colonization was not significantly different (p=0.7630) betweenplots with and without AVCC, but the colonization level was higher with mycorrhizal inoculation (86.6%) that in the control(71%). We conclude that AVCC and inoculation with mycorrhizae had a positive effect on species diversity of AMF androot colonization, respectively.El presente trabajo tuvo como objetivo conocer la densidad, abundancia y diversidad de especies de hongos micorrízicosarbusculares (HMA) asociadas al cultivo de maíz (Zea mays L.) en parcelas que han sido manejadas con bajos ingresos deinsumos externos y evaluar su respuesta a la aplicación de abono verde/cultivo de cobertura (AVCC) y biofertilizantes. Eltrabajo se realizó en siete parcelas de productores de maíz, de las cuales tres han sido manejadas con frijol nescafé (Mucunadeeringiana Merr.) como AVCC y cuatro sin dicho antecedente de manejo. En cada una de las parcelas se establecieroncuatro tratamientos de biofertilización: 1) inoculación con micorriza arbuscular, 2) aplicación de fertilizante orgánico foliar,3) inoculación con micorriza + fertilizante orgánico foliar, y 4) testigo, los cuales se ordenaron bajo un diseño de bloquescompletos al azar con siete repeticiones. En total se identificaron 23 morfoespecies, de las cuales 14 se llevaron a nivelde especie, siendo Glomus y Acaulospora los géneros predominantes. El número de especies con AVCC superó en 50%al obtenido sin AVCC. En las parcelas con AVCC se encontró el 91,3% de morfoespecies de HMA, mientras que enlas parcelas sin AVCC el 60,9%. El porcentaje de colonización micorrízica no varió significativamente (p=0,7630) entreparcelas con y sin AVCC, sin embargo el nivel de colonización fue más alto con inoculación de micorrizas (86,6%) que enel testigo (71%). Se concluye que el AVCC y la inoculación con micorrizas tuvieron un efecto positivo en la diversidad deespecies de HMA y en la colonización de la raíz, respectivamente

Impact of CD4 and CD8 dynamics and viral rebounds on loss of virological control in HIV controllers

Objective: HIV controllers (HICs) spontaneously maintain HIV viral replication at low level without antiretroviral therapy (ART), a small number of whom will eventually lose this ability to control HIV viremia. The objective was to identify factors associated with loss of virological control. Methods: HICs were identified in COHERE on the basis of \ue2\u89\ua55 consecutive viral loads (VL) \ue2\u89\ua4500 copies/mL over \ue2\u89\ua51 year whilst ART-naive, with the last VL \ue2\u89\ua4500 copies/mL measured \ue2\u89\ua55 years after HIV diagnosis. Loss of virological control was defined as 2 consecutive VL >2000 copies/mL. Duration of HIV control was described using cumulative incidence method, considering loss of virological control, ART initiation and death during virological control as competing outcomes. Factors associated with loss of virological control were identified using Cox models. CD4 and CD8 dynamics were described using mixed-effect linear models. Results: We identified 1067 HICs; 86 lost virological control, 293 initiated ART, and 13 died during virological control. Six years after confirmation of HIC status, the probability of losing virological control, initiating ART and dying were 13%, 37%, and 2%. Current lower CD4/CD8 ratio and a history of transient viral rebounds were associated with an increased risk of losing virological control. CD4 declined and CD8 increased before loss of virological control, and before viral rebounds. Discussion: Expansion of CD8 and decline of CD4 during HIV control may result from repeated low-level viremia. Our findings suggest that in addition to superinfection, other mechanisms, such as low grade viral replication, can lead to loss of virological control in HICs

All-sky Medium Energy Gamma-ray Observatory: Exploring the Extreme Multimessenger Universe

The All-sky Medium Energy Gamma-ray Observatory (AMEGO) is a probe class mission concept that will provide essential contributions to multimessenger astrophysics in the late 2020s and beyond. AMEGO combines high sensitivity in the 200 keV to 10 GeV energy range with a wide field of view, good spectral resolution, and polarization sensitivity. Therefore, AMEGO is key in the study of multimessenger astrophysical objects that have unique signatures in the gamma-ray regime, such as neutron star mergers, supernovae, and flaring active galactic nuclei. The order-of-magnitude improvement compared to previous MeV missions also enables discoveries of a wide range of phenomena whose energy output peaks in the relatively unexplored medium-energy gamma-ray band