Patricia Mussali-Galante

Inhaled vanadium pentoxide decrease gamma-tubulin of mouse testes at different exposure times

Vanadium is an important environmental and industrial pollutant whose concentrations have increased in the last decades. Due to its status as reproductive toxicant and a microtubule damaging agent, the present study investigated by immunohistochemistry the effect of the inhalation of vanadium pentoxide on gamma-tubulin within somatic and testicular germ cells. Male mice inhaled vanadium pentoxide (V2O5) (0.02 M) 1 h/twice a week for 12 weeks. Our results demonstrated that vanadium accumulates in the testes starting with the initial inhalation (24 h), and this pattern remained until the last week of treatment. In general, vanadium was capable of significantly decreasing the percentage of gamma-tubulin in all analyzed testicular cells (Sertoli, Leydig and germ cells) starting with the first week of treatment. For all cell types studied, regression analysis revealed a negative and significant relationship between the percentage of immunopositive cells to gamma-tubulin and exposure time, showing a time dependent response in all cases. Our findings suggest that alterations on this protein might imply changes in microtubule-involved function such as cell division, which in the testes might lead to damage in the spermatogenesis, leading probably to infertility.

Thrombocytosis induced in mice after subacute and subchronic V2O5 inhalation.

Reports about vanadium (V) inhalation toxicity on the hematopoietic system, specifically about coagulation are limited. Therefore, we decided to evaluate the effects of V with a complete blood count and morphologic analysis of platelets on blood smears. CD-1 male mice inhaled V2O5 0.02 M 1 h twice weekly over 12 weeks. Blood samples were obtained by direct heart puncture; Wright stained smears were used for platelet quantification. An increase in platelet count from the third week of exposure was observed, as well as the presence of megaplatelets. Our results demonstrate, for the first time, that V induces thrombocytosis and it might correlate with some thromboembolic diseases. Further analysis is needed to evaluate the functionality of these platelets as well as the cause of its increase.

Effect of a red oak species gradient on genetic structure and diversity of Quercus castanea (Fagaceae) in Mexico

Incipient reproductive barriers are a common characteristic of oak species. Disruption of these barriers promotes changes in diversity and genetic structure of the species involved. Quercus castanea is a red oak with wide geographic distribution in Mexico, which presents atypically high morphological variability when it occurs in sympatry with other red oak species, suggesting that hybridization may explain the observed variation. We tested if the genetic structure and diversity levels of Q. castanea are related to the number of red oak species growing in sympatry. In total, 14 microsatellite (SSRs) primers (six nSSRs and eight cpSSRs) were used in 120 Q. castanea individuals (20/site) belonging to six populations, where the number of red oak species associated varied from zero to five. Results showed a positive and significant relationship between the genetic diversity of Q. castanea and the number of red oak species growing in sympatry, regardless of the marker type or the parameter of genetic diversity analyzed. Also, we found a higher genetic differentiation of Q. castanea populations using cpSSRs in comparison with nSSRs. Our results suggest that temperate forests with high red oaks species richness co-dominated by Q. castanea promote the increase in this species genetic diversity. From a conservation perspective, high genetic diversity levels of foundation species such as Q. castanea may have positive cascade effects extending to other species in the community.

Hybridization of Quercus castanea (Fagaceae) across a red oak species gradient in Mexico

Interspecific gene flow between more than two species is a common phenomenon in oaks, which can occur simultaneously among different species, promoting the transfer of genetic material across species boundaries. However, the hybridization dynamics in multispecies hybrid zones remain unknown. In this study, we provide genetic evidence of hybridization and introgression of Quercus castanea across a natural gradient of red oak species richness. We analyzed five populations recognized morphologically as “pure” Q. castanea, one allopatric and four sympatric populations, where the number of red oak species associated with Q. castanea ranged from one to four. Also, one allopatric population of each red oak species that occurs in sympatry with Q. castanea was chosen as reference population (Q. crassipes, Q. laurina, Q. mexicana and Q. crassifolia). In total, six nSSRs were used in 10 and 20 individuals from each allopatric and sympatric populations, respectively. Our results showed that allopatric populations formed completely distinct genetic clusters. In sympatric populations, we found evidence of hybridization and introgression among Q. castanea and three of its associated red oak species. However, the occurrence and frequency of hybrids between Q. castanea and these species varied among stands. Our analyses provide evidence and new insights into hybridization and introgression dynamics within a Mexican red oak species complex, through a focal species, Q. castanea.

Effect of host-plant genetic diversity on oak canopy arthropod community structure in central Mexico

BackgroundRecently it has been proposed that the genetic diversity of foundation species influences the structure and function of the community by creating locally stable conditions for other species and modulating ecosystem dynamics. Oak species are an ideal system to test this hypothesis because many of them have a wide geographical distribution, and they are dominant elements of the forest canopy. In this study we explored the response of canopy arthropod community structure (diversity and biomass) to the level of genetic diversity of Quercus crassipes and Q. rugosa, two important canopy species. Also, we examined the effect of oak species and locality on some community structure parameters (diversity, biomass, rare species, and richness of arthropod fauna) of canopy arthropods. In total, 160 canopies were fogged in four localities at the Mexican Valley (ten trees per species per locality per season).ResultsQ. crassipes registered the highest number of rare species, diversity index, biomass, and richness in comparison with Q. rugosa. We found a positive and significant relationship between genetic diversity parameters and canopy arthropod diversity. However, canopy arthropod biomass registered an inverse pattern. Our results support the hypothesis that the genetic diversity of the host-plant species influences the assemblage of the canopy arthropod community.ConclusionsThe pattern found in our study provides a powerful tool when trying to predict the effects of the genetic diversity of the host-plant species on different community structure parameters, which permits assignment of a new conservation status to foundation species based on their genetic diversity.

Influence of forest type and host plant genetic relatedness on the canopy arthropod community structure of Quercus crassifolia

BackgroundQuercus crassifolia is an oak species with characteristics of foundation species, which is a canopy dominant element of different forest types that supports a wide diversity of associated species. Therefore, it is an excellent system to address important ecological questions. We analyzed the effect of individual genetic relatedness of the host plant, forest type (Abies-Quercus, Quercus-Pinus, and Quercus forest), and season (dry vs. rainy) on the canopy arthropod community structure. Thirty oak canopies were fogged (five individuals/season/forest type).ResultsWe identified 442 arthropod species belonging to 22 orders. The highest values of density, diversity, and richness were recorded during the rainy season for each forest type. Also, the non-metric multidimensional scaling (NMDS) analysis showed a separation of the host tree species for each forest type. During the rainy season, the highest values of density, diversity, and richness in each forest type were recorded. A separation of host tree was found for each forest type. In general, diversity and richness of canopy arthropods showed the following pattern: Abies-Quercus > Quercus-Pinus > Quercus, while density showed an inverse pattern. An increase of the diversity of canopy arthropods is significantly related to an increase of host plant genetic diversity, independently of the type of forest and of the season.ConclusionsIn terms of conservation, if arthropod species respond to genetic differences among host plants, it becomes important to conserve genetic diversity of foundation species, since it is fundamental to preserve diversity of their associated arthropod communities.

Response of Zea mays to multimetal contaminated soils: a multibiomarker approach

Heavy metals present in mine tailings pollute agroecosystems, put the integrity of the environment at risk and become a major route of exposure to humans. The present study was carried out in Taxco, Guerrero, Mexico, where millions of tons of mine tailings have been deposited. Soils from this region are used for agricultural activities. Maize (Zea mays) was selected as a test plant, because it is one of the most common and important cereal crops in Mexico and worldwide. Thirteen metals were selected and their bioaccumulation in roots, leaves and fruits were measured in plants cultivated in soils contaminated with mine tailings and those cultivated in non-contaminated soils. The effect of metal bioaccumulation on: macro and micromorphology, size, biomass, coloration leaf patterns and on DNA damage levels in different structures were determined. The bioaccumulation pattern was: root > leaf > fruit, being only Mn and Cr bioaccumulated in all three structures and V in the roots and leaves. A significant effect of metal bioaccumulation on 50% of the size and leaf shape and 55% of the biomass characters in Z. mays exposed plants was detected. Regarding micromorphological characters, a significant effect of metal bioaccumulation on 67% of the leaf characters and on 100% of the color basal leaf characters was noted. The effect of metal bioaccumulation on the induction of DNA damage (leaf > fruit > root) was detected employing single cell gel electrophoresis analysis. An approach, in which multi endpoints are used is necessary to estimate the extent of the detrimental effects of metal pollution on agroecosystem integrity contaminated with mine tailings.

Genetic variation in foundation species governs the dynamics of trophic interactions

Abstract Various studies have demonstrated that the foundation species genetic diversity can have direct effects that extend beyond the individual or population level, affecting the dependent communities. Additionally, these effects may be indirectly extended to higher trophic levels throughout the entire community. Quercus castanea is an oak species with characteristics of foundation species beyond presenting a wide geographical distribution and being a dominant element of Mexican temperate forests. In this study, we analyzed the influence of population (He) and individual (HL) genetic diversity of Q. castanea on its canopy endophagous insect community and associated parasitoids. Specifically, we studied the composition, richness (S) and density of leaf-mining moths (Lepidoptera: Tischeridae, Citheraniidae), gall-forming wasps (Hymenoptera: Cynipidae), and canopy parasitoids of Q. castanea. We sampled 120 trees belonging to six populations (20/site) through the previously recognized gradient of genetic diversity. In total, 22 endophagous insect species belonging to three orders (Hymenoptera, Lepidoptera, and Diptera) and 20 parasitoid species belonging to 13 families were identified. In general, we observed that the individual genetic diversity of the host plant (HL) has a significant positive effect on the S and density of the canopy endophagous insect communities. In contrast, He has a significant negative effect on the S of endophagous insects. Additionally, indirect effects of HL were observed, affecting the S and density of parasitoid insects. Our results suggest that genetic variation in foundation species can be one of the most important factors governing the dynamics of tritrophic interactions that involve oaks, herbivores, and parasitoids.

Additional file 1: of Morphological variation of Cosmos bipinnatus (Asteraceae) and its relation to abiotic variables in central Mexico

Character intercorrelation within and between vegetative and reproductive macromorphological characters of Cosmos bipinnatus. Only significant correlation coefficients (P