Antigenotoxic Effect of Ascorbic Acid and Resveratrol in Erythrocytes of Ambystoma mexicanum, Oreochromis niloticus and Human Lymphocytes Exposed to Glyphosate.

Glyphosate is a controversial herbicide. Its genotoxicity and presence in various ecosystems have been reported. The use of ascorbic acid and resveratrol could protect different organisms from glyphosate-induced genetic damage. In the present study, specific genetic damage induced by glyphosate was evaluated in erythrocytes of Oreochromis niloticus, Ambystoma mexicanum and human lymphocytes. Simultaneously, the antigenotoxic capacity of various concentrations of ascorbic acid and resveratrol was evaluated by means of pretreatment and simultaneous treatment protocols. The 0.03, 0.05 and 0.07 mM concentrations of glyphosate induced significant genotoxic activity (p < 0.05) in human lymphocytes and in erythrocytes of the species studied, and could cause genomic instability in these populations. The reduction in genetic damage observed in human lymphocytes exposed to high concentrations of glyphosate is only apparent: excessive genetic damage was associated with undetectable excessive tail migration length. A significant (p < 0.05) antigenotoxic effect of ascorbic acid and resveratrol was observed in all concentrations, organisms and protocols used. Both ascorbic acid and resveratrol play an important role in maintaining the integrity of DNA. Ascorbic acid in Oreochromis niloticus, Ambystoma mexicanum reduced glyphosate-induced genetic damage to a basal level. Therefore, our data indicate that these antioxidants could help preserve the integrity of the DNA of organisms exposed to glyphosate. The consumption of antioxidants is a useful tool against the genotoxicity of glyphosate.

New Species of Bioluminescent Mycena Sect. Calodontes (Agaricales, Mycenaceae) from Mexico.

Mycena section Calodontes is macromorphologically distinguished by the collybioid or mycenoid basidiome, which is pink, purple, or violet, and, rarely, reddish-brown or yellowish. It is further characterized by the presence of oxalate crystals in the basal mycelium. The section comprises approximately 40 taxa, of which only five species and one variety exhibit bioluminescence. As part of an extensive study on Mycena sect. Calodontes in Mexico, specimens belonging to this section were collected and subjected to morphological analysis. Sequences from the nuclear internal transcribed spacer (ITS) of nuclear ribosomal DNA, RNA polymerase II large subunit Rpb1 (rpb1), and translation elongation factor-1α (Tef-1α) were generated to infer the relationships within Mycena sect. Calodontes using maximum likelihood and Bayesian inference. The phylogenetic evidence, along with the macro- and micromorphological features, supported the recognition of five new bioluminescent species within Mycena sect. Calodontes. Detailed macro- and micromorphological descriptions, line-drawing illustrations, and light and dark photographs of the new species are provided.

The Ganoderma weberianum-resinaceum lineage: multilocus phylogenetic analysis and morphology confirm G. mexicanum and G. parvulum in the Neotropics.

Many species of Ganoderma exhibit a high phenotypic plasticity. Hence, particularly among them, the morphological species concept remains difficult to apply, resulting in a currently confused taxonomy; as a consequence, the geographical distribution range of many species also remains very uncertain. One of the areas with a strong uncertainty, as far as morphological species concept is concerned, is the Neotropics. It is common that names of species described from other regions, mainly from northern temperate areas, have been applied to Neotropical species. The aim of the present study was to determine which species might lay behind the G. weberianum complex in the Neotropics, using morphological studies and phylogenetic inferences based on both single (ITS) and multilocus (ITS, rpb2, and tef1-α) sequences. The results indicated that G. weberianum sensu Steyaert, which is the usually accepted concept for this taxon, was absent from the Neotropics. In this area, G. weberianum sensu Steyaert encompassed at least two phylogenetic species, which are tentatively, for the time being, identified as belonging to G. mexicanum and G. parvulum. These two species could be distinguished morphologically, notably by the ornamentation or its absence on their chlamydospores. The results also showed that additional species from the Neotropics might still exist, including, e.g., G. perzonatum, but their circumscription remains uncertain until now because of the paucity of material available. Furthermore, it was found that the current concept of G. resinaceum embraced a complex of species.

A new stipitate species of Crepidotus from India and Thailand, with notes on other tropical species.

A new Asian species of Crepidotus (Basidiomycota, Agaricales), C. asiaticus, is presented based on morphological and nuc rDNA internal transcribed spacer (ITS1-5.8S-ITS2 = ITS) and large subunit (28S) sequence data. This new species, found in India and Thailand, is characterized by the centrally stipitate medium-sized basidiomata, orange to reddish brown pileus, white to brownish orange lamellae, and white stipe. Based on morphology, C. asiaticus is similar to the neotropical C. thermophilus. However, the microscopic characters, especially the size and shape of the basidiospores, can be used to distinguish these two taxa, as well as their geographic distributions. Further, the phylogenetic position of C. asiaticus is unique based on ITS and 28S nuc rDNA sequences. Melanomphalia argipoda, described by Singer from Ecuador, is also a stipitate Crepidotus based on an ITS sequence of the type specimen, so the new combination is proposed here. Phylogenetically, the three species form a monophyletic group with the Asiatic C. asiaticus forming the sister lineage to the neotropical C. argipodus and C. thermophilus.

Alpha-thalassemia in a selected population of Mexico

Objetivo. Identificar con técnicas de biología molecular, los de Ó-Thal en poblaciones hospitalarias seleccionadas. Métodos. Diez y ocho propositi con datos hematológicos y bioquímicos sugestivos de talasemia-Ó, seleccionados de 356 pacientes con probable hemoglobinopatía provenientes de cuatro hospitales de dos ciudades, se investigaron para seis alelos comunes de talasemia-Ó. Los estudios moleculares se realizaron por reacción en cadena de la polimerasa y digestión con enzimas de restricción específicas. Resultados. El alelo Ó se identificó en dos casos: el estudio familiar mostró el mismo alelo en la madre de ambos y se detectó además heterocigocidad para HbS en uno de ellos. El análisis con Apa I reveló en ambos pacientes la deleción clase I que es el alelo más comúnmente observado en el mundo. Este estudio mostró 2/356 (0.6 por ciento) de portadores Ó, una frecuencia baja comparada con la observada en otras poblaciones del mundo. La ausencia de los otros alelos sugiere que en México la talasemia-Ó es molecularmente tan heterogénea como la talasemia-ß