Effect of the natural establishment of two plant species on microbial activity, on the composition of the fungal community, and on the mitigation of potentially toxic elements in an abandoned mine tailing.

In Mexico, millions of tons of mining wastes are deposited in the open pit. Their content in potentially toxic elements (PTE) represents an environmental risk. In the tailings, pioneer plant communities are established, associated with a determined diversity of fungi; plants, and fungi are fundamental in the natural rehabilitation of mining wastes. The objective was to evaluate the impact of the natural establishment of two plant species on the microbial activity, on the composition of the fungal community, and on the mitigation of the effect of PTE in a contaminated mine tailing. In a tailing, we selected three sites: one non-vegetated; one vegetated by Reseda luteola, and one vegetated by Asphodelus fistulosus. In the substrates, we conducted a physical and chemical characterization; we evaluated the enzymatic activity, the mineralization of the carbon, and the concentration of PTE. We also determined the fungal diversity in the substrates and in the interior of the roots, and estimated the accumulation of carbon, nitrogen, phosphorus and PTE in plant tissues. The tailings had a high percentage of sand; the non-vegetated site presented the highest electric conductivity, and the plant cover reduced the concentration of PTE in the substrates. Plants increased the carbon content in tailings. The enzymatic activities of ß-glucosidase and dehydrogenase, and the mineralization of carbon were highest at the site vegetated with A. fistulosus. Both plant species accumulated PTE in their tissues and exhibited potential in the phytoremediation of lead (Pb), cadmium (Cd), and copper (Cu). Fungal diversity was more elevated at the vegetated sites than in the bare substrate. Ascomycota prevailed in the substrates; the substrates and the plants shared some fungal taxa, but other taxa were specific. The plant coverage and the rhizosphere promoted the natural attenuation and a rehabilitation of the extreme conditions of the mining wastes, modulated by the plant species.

Pioneer plant species and fungal root endophytes in metal-polluted tailings deposited near human populations and agricultural areas in Northern Mexico.

As a consequence of industrial mining activity, high volumes of tailings are scattered around Mexico. Frequently, tailings contain heavy metals (HM) which entail threats against all organisms. The aim of this research was to identify plants and root fungal endophytes in polymetallic polluted tailings with the potential to be used in strategies of bioremediation. Four deposits of mine wastes, situated in a semi-arid region near urban and semi-urban populations, and agricultural areas, were studied. The physical and chemical characteristics of substrates, accumulation of HM in plant tissues, root colonization between arbuscular mycorrizal (AMF) and dark septate endophyte (DSE) fungi, and the identification of DSE fungi isolated from the roots of two plant species were studied. Substrates from all four sites exhibited extreme conditions: high levels in sand; low water retention; poor levels in available phosphorus and nitrogen content; and potentially toxic levels of lead (Pb), cadmium (Cd), and zinc (Zn). The native plants Lupinus campestris, Tagetes lunulata, and Cerdia congestiflora, as well as the exotic Cortaderia selloana and Asphodelus fistulosus, demonstrated a relevant potential role in the phytostabilization and/or phytoextraction of Pb, Cd, and Zn, according to the accumulation of metal in roots and translocation to shoots. Roots of eleven analyzed plant species were differentially co-colonized between AMF and DSE fungi; the presence of arbuscules and microsclerotia suggested an active physiological interaction. Fourteen DSE fungi were isolated from the inner area of roots of T. lunulata and Pennisetum villosum; molecular identification revealed the predominance of Alternaria and other Pleosporales. The use of native DSE fungi could reinforce the establishment of plants for biological reclamation of mine waste in semi-arid climate. Efforts are needed in order to accelerate a vegetation practice of mine wastes under study, which can reduce, in turn, their potential ecotoxicological impact on organisms, human populations, and agricultural areas.

Vitamin D Deficiency and Supplementation in Cardiovascular Disorders.

Cardiovascular disease (CVD) is the leading cause of death in developed countries. Similarly, the frequency of vitamin D deficiency is increasing, and a number of epidemiologic and clinical studies have suggested that there is an increased risk of CVD among people with depletion of this vitamin. This has raised much interest in the potential pathogenic and therapeutic role of vitamin D in CVD. However, randomized trials and meta-analyses have not shown a clear benefit of vitamin D supplementation with respect to cardiovascular events. Herein, we provide a comprehensive review of the most relevant evidence to date regarding vitamin D deficiency and supplementation, and their respective impact on CVD prevention and treatment.

Pharmacogenetic screening of N-acetyltransferase 2, thiopurine s-methyltransferase, and 5,10-methylene-tetrahydrofolate reductase polymorphisms in Northwestern Mexicans.

Specific information about the population pharmacogenetics can be the starting point to study the inheritance of these traits, to design individual drug therapy, and to develop new drugs rationally. Pharmacogenetic studies have been performed in some regions of Mexico, such as Central and Northeast, but this kind of study has not been conducted in the Northwest region so far. Here, we report the distribution of NAT2, TPMT, and MTHFR gene polymorphisms in Baja California, Mexico. We found that our population sample exhibits allele and genotype frequencies that are highly similar to those observed in Caucasian populations, although it should be noted that there are slight similarities with those determined in other populations. As allelic variants of drug-metabolizing enzymes are prevalent in our population, it is important to consider pharmacogenetic testing as part of the standard diagnostic protocols before medication.