Los mamíferos salvajes terrestres como bioindicadores: nuevos avances en Ecotoxicología

Ecotoxicology as science pretends to correctly identify problems associated to the presence and the effect of chemical substances in the environmental and the wildlife. In this field, the presence of heavy metals on ecosystems constitutes a serious problem, for both their elevated environmental persistence and high toxicity for wildlife. In this sense, the present paper shows a review concerning more recent advances in the modern biomonitoring methodologies, using wild mammals and making differences between destructive and non-destructive methods. L’Ecotoxicologie comme science cherche identifier correcte des problèmes dérivés de la présence et effet des substances chimiques dans l’environnement et les êtres vivants. Dans ce domaine, la présence des métaux lourds dans les écosystèmes constitue un problème très sérieux, pour son élevé persistance environnementale et son haute toxicité pour tous les organismes vivants. Dans ce sens, le présent travaille fait une révision à propos des progrès dans les modernes méthodologies de biomonitoring, avec l’emploie des mammifères sauvages et en faisant une distinction à la méthodologie employee (méthodes destructives et non destructives).La Ecotoxicología como ciencia busca identificar adecuadamente los problemas derivados de la presencia y efecto de sustancias químicas en el medio ambiente y los seres vivos. Dentro de este campo, la presencia de metales pesados en los ecosistemas constituye un serio problema, tanto por su elevada persistencia medioambiental como por su alta toxicidad para todos los organismos vivos. En este sentido, el presente trabajo realiza una revisión sobre los avances más recientes ocurridos en las modernas metodologías de biomonitorización, empleando para ello mamíferos salvajes y haciendo distinción en la metodología empleada (métodos destructivos y no destructivos)

The Iron abundance in Galactic Planetary Nebulae

We constrain the iron abundance in a sample of 33 low-ionization Galactic planetary nebulae (PNe) using [Fe III] lines and correcting for the contribution of higher ionization states with ionization correction factors (ICFs) that take into account uncertainties in the atomic data. We find very low iron abundances in all the objects, suggesting that more than 90% of their iron atoms are condensed onto dust grains. This number is based on the solar iron abundance and implies a lower limit on the dust-to-gas mass ratio, due solely to iron, of M_dust/M_gas>1.3x10^{-3} for our sample. The depletion factors of different PNe cover about two orders of magnitude, probably reflecting differences in the formation, growth, or destruction of their dust grains. However, we do not find any systematic difference between the gaseous iron abundances calculated for C-rich and O-rich PNe, suggesting similar iron depletion efficiencies in both environments. The iron abundances of our sample PNe are similar to those derived following the same procedure for a group of 10 Galactic H II regions. These high depletion factors argue for high depletion efficiencies of refractory elements onto dust grains both in molecular clouds and AGB stars, and low dust destruction efficiencies both in interstellar and circumstellar ionized gas.Comment: Accepted for publication in ApJ. 15 pages, 4 Postscript figures, corrected typos, Tables 2 and 3 correcte

Non-random distribution of biocrust in a natural arid environment in the northern mexican plateau

Abstract. Biocrust, as photosynthetic organisms, has been considered to show an inversely proportional relationship with vascular plant cover. However, some studies report association and facilitation relationships between them. This research explores whether i) biocrust is associated with shrub species, ii) biocrust cover is higher in undershrub microenvironments than in open areas between plants and, iii) soil moisture and solar radiation affect biocrust distribution. Biocrust cover was analyzed by morphotype in microenvironments under the canopy of two dominant shrub species (Larrea tridentata and Parthenium incanum) and in open areas. Soil moisture and solar radiation were recorded at each microenvironment. Thirty-three interception lines (975 points) were used to analyze the association between vascular plants and biocrust and 20 sampling plots to estimate morphotype cover. Results reveal a positive association between biocrust and plant species compared to open areas. Lichens and cyanobacteria showed a higher cover under L. tridentata than under P. incanum and in open areas, suggesting a species-specific facilitative association with L. tridentata, maybe due to a higher soil water content in this microenvironment. Mosses had lower cover in the open area where the highest solar radiation was recorded. Lichens and cyanobacteria distribution appeared to be related to soil moisture. Keywords: creosote bush, cyanobacteria, lichens, mosses, northeastern Mexic

Loading of antibiotic into biocoated hydroxyapatite nanoparticles: smart antitumor platforms with regulated release

In this research we propose a nanoplatform for anticancer therapy that is based on the combination of three components: (1) an antibiotic to target selectively the mitochondria of cancer cells, inhibiting their functions; (2) mineral nanoparticles (NPs) able to encapsulate the antibiotic and to enter into the cells across the cell membrane; and (3) a biocoating to protect the antibiotic during and/or after its regulated release, increasing its therapeutic efficacy. Chloramphenicol (CAM), a prototypical wide-spectrum antibiotic, has been used to induce mitochondrial-dysfunctions in cancer cells. Different in situ synthetic strategies have been tested to load such antibiotic into both crystalline hydroxyapatite (cHAp) and amorphous calcium phosphate (ACP) NPs. cHAp NPs showed higher loading capacity, in terms of encapsulation and superficial adsorption of CAM, and slower antibiotic release than ACP NPs. On the other hand, the protecting role played by biocoatings based on pyrophosphate and, especially, triphosphate was greater than that of biophosphonates, the anticancer therapeutic efficacy of CAM being maximized by the former. In vitro studies using healthy and cancer cell lines have demonstrated that in situ CAM-loaded cHAp NPs coated with triphosphate selectively kill a great population of cancer cells, evidencing the potential of this nanoplatform in cancer treatment.Peer ReviewedPostprint (published version