Low heat tolerance and high desiccation resistance in nocturnal bees and the implications for nocturnal pollination under climate change.

Predicting insect responses to climate change is essential for preserving ecosystem services and biodiversity. Due to high daytime temperatures and low humidity levels, nocturnal insects are expected to have lower heat and desiccation tolerance compared to diurnal species. We estimated the lower (CTMin) and upper (CTMax) thermal limits of Megalopta, a group of neotropical, forest-dwelling bees. We calculated warming tolerance (WT) as a metric to assess vulnerability to global warming and measured survival rates during simulated heatwaves and desiccation stress events. We also assessed the impact of body size and reproductive status (ovary area) on bees' thermal limits. Megalopta displayed lower CTMin, CTMax, and WTs than diurnal bees (stingless bees, orchid bees, and carpenter bees), but exhibited similar mortality during simulated heatwave and higher desiccation tolerance. CTMin increased with increasing body size across all bees but decreased with increasing body size and ovary area in Megalopta, suggesting a reproductive cost or differences in thermal environments. CTMax did not increase with increasing body size or ovary area. These results indicate a greater sensitivity of Megalopta to temperature than humidity and reinforce the idea that nocturnal insects are thermally constrained, which might threaten pollination services in nocturnal contexts during global warming.

AP-3 complex subunit delta gene, ap3d1, regulates melanogenesis and melanophore survival via autophagy in zebrafish (Danio rerio).

Zebrafish are an emerging model organism to study the syndromic albinism disorder, Hermansky-Pudlak syndrome (HPS), due to visible pigment development at 24 hours postfertilization, and conserved melanogenesis mechanisms. We describe crasher, a novel HPS type 10 (HPS10) zebrafish model, with a mutation in AP-3 complex subunit delta gene, ap3d1. Exon 14 of ap3d1 is overexpressed in crasher mutants, while the expression of ap3d1 as a whole is reduced. ap3d1 knockout in *AB zebrafish recapitulates the mutant crasher phenotype. We show ap3d1 loss-of-function mutations cause significant expression changes in the melanogenesis genes, dopachrome tautomerase (dct) and tyrosinase-related protein 1b (tyrp1b), but not tyrosinase (tyr). Last, Generally Applicable Gene-set Enrichment (GAGE) analysis suggests autophagy pathway genes are upregulated together in crasher. Treatment with autophagy-inhibitor, bafilomycin A1, significantly decreases melanophore number in crasher, suggesting ap3d1 promotes melanophore survival by limiting excessive autophagy. crasher is a valuable model to explore the regulation of melanogenesis gene expression and pigmentation disease.

Citrus juice extraction systems: effect on chemical composition and antioxidant activity of clementine juice.

Clementines are especially appreciated for their delicious flavor, and recent years have seen a great increase in the consumption of clementine juice. In previous decades, antioxidant compounds have received particular attention because of widely demonstrated beneficial health effects. In this work, the organoleptic, volatile flavor, and antioxidant quality of clementine juice were studied with regard to the influence on them by different juice extraction systems: plug inside fruit and rotating cylinders. The results showed that juice extracted by the former method presented higher yields and hesperidin content, which was related to higher antioxidant activity, demonstrated by ORAC and LDL assays. The organoleptic quality was not affected by the processing technique, whereas there were significant differences in the chemical flavor profile. There are important differences in chemical and functional quality between juice extraction techniques, which must be taken into account when employing processing systems to produce high-quality products.

Aporte crítico ll análisis de la normatividad ambiental / Criticalcontribuution to the analysis of environmental normativity

La normatividad ambiental internacional, que surge desde la declaración de Estocolmo en 1972, no ha logrado disminuir la contaminación ambiental sino que, como se observa en los más diversos informes especializados sobre el tema, los peligros que enfrenta la vida en el planeta son cada vez más inminentes. Lo anterior se debe a una comprensión errada del problema, pues no consiste -como es presentado en Nuestro Futuro Común- en la tecnología en sí misma, sino en el desarrollo del modo de producción que corresponde al modo de vida desarrollado en la sociedad burguesa; tema que no es analizado de manera crítica en ninguno de los discursos elaborados desde los organismos multilaterales. De igual forma, gran parte de las normas técnicas construidas como el tratado de Kyoto, a pesar de ser limitadas en sus alcances, no han logrado ser implementadas debido a que el poder económico de las naciones y de los grandes consorcios define por prioridad sus ganancias por encima de la vida.

International environmental regulations that emerged from the Stockholm Declaration adopted in 1972 haven’t been able to reduce environmental pollution; rather, as observed in the most diverse specialized reports, the dangers to life on the planet are increasing. This is because environmental problems have been misunderstood, since the problem doesn’t consist in, as presented in Our Common Future, in technology itself, but in the development of the mode of production in the bourgeois society. However, this element is not critically analyzed in any of the speeches from multilateral agencies. Similarly, several technical regulations such as the Kyoto Protocol, in spite of being limited, have not been implemented because of the economic power of nations and because big companies prioritize their earnings over life.

Crítica a las ciencias agrarias / Criticism to agaarian sciences

La crisis ambiental desatada en el actual modo de producción cuestiona el quehacer de las ciencias agrarias, dado que las tecnologías por ellas elaboradas han devenido en el deterioro de la vida en los ecosistemas. Tales desarrollos se realizan bajo el argumento del ejercicio científico que sustenta un objetivo para imponer su saber violento que busca la dominación de la naturaleza más que su explicación y la ordenación de la misma en teorías, cual es el quehacer científico. Sobre esta lógica, dichas ciencias especializadas dentro de los diversos campos de la división del trabajo han tenido por principio el monocultivo, forma característica de la agricultura desarrollada dentro del proceso de producción de mercancías de la sociedad burguesa, razón por la cual sus logros no comprenden las dinámicas de la vida en los ecosistemas, acelerando la entropía, generando con ello un deterioro de la vida en el planeta, lo que sólo puede ser superado en la medida en la que el hombre desde su trabajo, que le da formas a la sustancia de la naturaleza, se reconcilie con ella por medio de su acción consciente.

The environmental crisis caused by the current mode of production criticizes the labor of Agrarian Sciences, due to the fact that they produced technologies that have deteriorated life in ecosystems. These developments have been carried out claiming to be exercising their scientific labor supporting the goal to impose their violent knowledge, which seeks to control nature, instead of its explanation and organization in theories, their true scientific duty. Based on this logic, said sciences specialized in the diverse sectors of the division of labor aimed at single-crop farming, the characteristic form of agriculture developed within the goods production process of bourgeois society. Therefore, the achievements of Agrarian Sciences don’t address the dynamics of life in ecosystems, but rather accelerate entropy, and thus deteriorate life on the planet; this can only be overcome if humans by their work, which shapes nature, reconcile with nature through their conscious action.