Nichima gen. nov. (Alismataceae) based on reproductive structures from the Oligocene-Miocene of Mexico.

PREMISE: Alismataceae, a sub-cosmopolitan family with ca. 17 genera and 113 species, is a large group of aquatic plants. Compression/impressions and bioinclusions of reproductive parts in amber support the documentation of the lineage in low-latitude North America. In Mexico, fossil aquatic plants have been infrequently documented. The new reproductive structures exhibit characteristics of Alismataceae, whose fossil record is mainly documented in the northern hemisphere through of fruits and seeds. METHODS: We described and compared 150 samples of reproductive structures preserved as impressions/compressions from the Oligocene Los Ahuehuetes locality in the state of Puebla, and two bioinclusions from the Miocene amber of Simojovel de Allende in the state of Chiapas, Mexico with extinct and extant taxa. Using a parsimony analysis based on 29 floral characters of 17 extant genera of the Alismataceae, we evaluated the relationship between the fossil material and potential living relatives. RESULTS: We discovered a new genus Nichima based on a perfect, actinomorphic flower with an expanded receptacle, three persistent sepals with multiple vasculatures, delicate and caducous petals, six stamens, and a gynoecium composed of three to more superior carpels, maturing into achenes. These characteristics resemble flowers of Alismataceae. Nichima represents an extinct member of the family, with two new species described here, Nichima magalloniae L. Hern., Cevallos-Ferriz et Hernández-Damián sp. nov. and Nichima gonzalez-medranoi L. Hern., Cevallos-Ferriz et Hernández-Damián, sp. nov. Their phylogenetic position suggests affinity with a clade that includes Baldiella, Echinodorus, and Alisma. CONCLUSIONS: Reproductive structures from the Cenozoic of Mexico support the identification of a new extinct genus, Nichima, evidencing the extensive history of Alismataceae in North America's low latitudes and suggesting a southern extension of the boreotropical flora.

Impact of Drying Process on the Phenolic Profile and Antioxidant Capacity of Raw and Boiled Leaves and Inflorescences of Chenopodium berlandieri ssp. berlandieri.

C. berlandieri ssp. berlandieri (C. berlandieri) is one of the most common members of the group of plants known as quelites, which are dark leafy greens widely consumed in Mexico. This study aimed to evaluate the impact of two drying procedures (oven drying and freeze-drying/lyophilization) on the polyphenolic composition, antioxidant capacity, and proximal chemical analysis of C. berlandieri leaves and inflorescences (raw or boiled). The results indicated that the raw freeze-dried samples had higher amounts (p < 0.05) of total phenolic compounds, total flavonoids, and antioxidant capacity, mainly in the inflorescence. The oven-dried samples showed an increased concentration of polyphenols after boiling, while the lyophilized samples showed a slightly decreased concentration. The drying process was observed to have little impact on the proximal chemical composition. Quantification by UPLC-DAD-ESI-QToF/MS identified up to 23 individual phenolic compounds, with freeze-dried samples showing higher amounts of individual compounds compared with oven-dried. Procyanidin B2 was found exclusively in the inflorescences. The inflorescences have a higher content of phenolic compounds and greater antioxidant capacity than the leaves. Regardless of the drying process, the leaves and inflorescences of C. berlandieri contain an interesting variety of phenolic compounds that may have beneficial effects on health.

Phenolic profile and antioxidant capacity of Pithecellobium dulce (Roxb) Benth: a review.

Pithecellobium dulce (Roxb) Benth (P. dulce), known as "guamúchil", is a tree native to the American continent. Various parts of the tree are used in traditional medicine, primarily for treating gastrointestinal disorders. The phenolic compounds and antioxidant capacity of this plant are largely responsible for the beneficial health effects attributed to it. A number of authors have studied the antioxidant capacity and phenolic compounds of the aril, seed, leaf and root of P. dulce using various methodologies, which can differ considerably in variables such as environmental factors, type of drying, temperature, the way the sample is stored, and the use of different solvents in the various extraction methods. Even methods of quantification by HPLC vary tremendously. This paper summarizes the existing research carried out to date on determining the phenolic profile and antioxidant capacity of P. dulce.

Estimation of genetic variation in closely related cycad species in Ceratozamia (Zamiaceae: Cycadales) using RAPDs markers.

The Ceratozamia norstogii complex from Southern Mexico is made up of four closely related taxa and occurs in similar habitats (Quercus forest). All have linear-lanceolate leaflets with great similarity between them, especially in juvenile stages, but differentiate with age. There has been debate regarding delimitation of species due to character loss in herbarium specimens. The aim of this study was to determine the genetic variation, and to measure genetic similarity between the four taxa. We studied populations in Cintalapa (Chiapas) for C. alvarezii and C. norstogii; the Sierra Atravesada (Oaxaca) for C. chimalapensis, and Villa Flores (Chiapas) for C. mirandae. One population for each taxon was sampled (only one population is known for C. alvarezii) 11-15 randomly chosen adult individuals were sampled. Twenty-eight primers were tested of which five were polymorphic using the RAPD'S technique. The data were analyzed using Bayesian methods. Results revealed low genetic diversity, and a differentiation was found between species, suggesting a recent divergence. A previous morphological and anatomical study on the complex has found the taxa to be distinct. However, the results of this study have shown that the C. norstogii species complex is in a divergence process, probably through genetic drift and founder effects.

A measure of regularity for polygonal mosaics in biological systems.

BACKGROUND: The quantification of the spatial order of biological patterns or mosaics provides useful information as many properties are determined by the spatial distribution of their constituent elements. These are usually characterised by methods based on nearest neighbours distances, by the number of sides of cells, or by angles defined by the adjacent cells. METHODS: A measure of regularity in polygonal mosaics of different kinds in biological systems is proposed. It is based on the condition of eutacticity, expressed in terms of eutactic stars, which is closely related to regularity of polytopes. Thus it constitutes a natural measure of regularity. The proposed measure is tested with numerical and real data. Numerically is tested with a hexagonal lattice that is distorted progressively and with a non-periodic regular tiling. With real data, the distribution of oak trees in forests from three locations in the State of Querétaro, Mexico, and the spiral pattern of florets in a flowering plant are characterised. RESULTS: The proposed measure performs well and as expected while tested with a numerical experiment, as well as when applied to a known non-periodic tiling of the plane. Concerning real data, the measure is sensitive to the degree of perturbation observed in the distribution of oak trees and detects high regularity in a phyllotactic pattern studied. CONCLUSIONS: The measure here proposed has a clear geometrical meaning, establishing what regularity means, and constitute an advantageous general purposes alternative to analyse spatial distributions, capable to indicate the degree of regularity of a mosaic or an array of points.

Metabarcoding of the phytotelmata of Pseudalcantarea grandis (Bromeliaceae) from an arid zone.

BACKGROUND: Pseudalcantarea grandis (Schltdl.) Pinzón & Barfuss is a tank bromeliad that grows on cliffs in the southernmost portion of the Chihuahuan desert. Phytotelmata are water bodies formed by plants that function as micro-ecosystems where bacteria, algae, protists, insects, fungi, and some vertebrates can develop. We hypothesized that the bacterial diversity contained in the phytotelma formed in a bromeliad from an arid zone would differ in sites with and without surrounding vegetation. Our study aimed to characterize the bacterial composition and putative metabolic functions in P. grandis phytotelmata collected in vegetated and non-vegetated sites. METHODS: Water from 10 individuals was sampled. Five individuals had abundant surrounding vegetation, and five had little or no vegetation. We extracted DNA and amplified seven hypervariable regions of the 16S gene (V2, V4, V8, V3-6, 7-9). Metabarcoding sequencing was performed on the Ion Torrent PGM platform. Taxonomic identity was assigned by the binning reads and coverage between hit and query from the reference database of at least 90%. Putative metabolic functions of the bacterial families were assigned mainly using the FAPROTAX database. The dominance patterns in each site were visualized with rank/abundance curves using the number of Operational Taxonomic Units (OTUs) per family. A percentage similarity analysis (SIMPER) was used to estimate dissimilarity between the sites. Relationships among bacterial families (identified by the dominance analysis and SIMPER), sites, and their respective putative functions were analyzed with shade plots. RESULTS: A total of 1.5 million useful bacterial sequences were obtained. Sequences were clustered into OTUs, and taxonomic assignment was conducted using BLAST in the Greengenes databases. Bacterial diversity was 23 phyla, 52 classes, 98 orders, 218 families, and 297 genera. Proteobacteria (37%), Actinobacteria (19%), and Firmicutes (15%) comprised the highest percentage (71%). There was a 68.3% similarity between the two sites at family level, with 149 families shared. Aerobic chemoheterotrophy and fermentation were the main metabolic functions in both sites, followed by ureolysis, nitrate reduction, aromatic compound degradation, and nitrogen fixation. The dominant bacteria shared most of the metabolic functions between sites. Some functions were recorded for one site only and were related to families with the lowest OTUs richness. Bacterial diversity in the P. grandis tanks included dominant phyla and families present at low percentage that could be considered part of a rare biosphere. A rare biosphere can form genetic reservoirs, the local abundance of which depends on external abiotic and biotic factors, while their interactions could favor micro-ecosystem resilience and resistance.

Reassessment of the extinction risk status of the ponytail palm Beaucarnea inermis / Reevaluación del riesgo de extinción de la pata de elefante Beaucarnea inermis

Abstract Beaucarnea inermis is an endemic species from Northeast Mexico, in the states of San Luis Potosí and Tamaulipas. It is appreciated as an ornamental plant, so its populations are subject to the poaching of individuals for illegal trade. Previous studies determined that their populations have been affected due to the disturbance since the incidence of anthropogenic activities affects the viability of the species. Here we determine the current conservation status of B. inermis and identify their main risk factor by performing an extinction risk assessment based on the Annex II "Method for Evaluation of Risk of Extinction of Plants in Mexico". We studied 10 populations of B. inermis from protected and non-protected areas in San Luis Potosí and Tamaulipas. We considered the MER criteria: A) geographical distribution characteristics, B) habitat characteristics, C) intrinsic biological vulnerability, and D) impact of human activity. Using field and analyzed data, the MER assessment gives 1.91 points that confirm B. inermis is correctly classified as an Endangered species. The natural protected areas where the species occurs represent cores for its protection; however, the surface of these areas may not be sufficient without biological corridors that connect them.

Resumen Beaucarnea inermis es una especie endémica del Noroeste de México distribuida en los estados de San Luis Potosí y Tamaulipas. Es apreciada como planta ornamental, por lo que sus poblaciones están sujetas al saqueo de individuos para su comercialización ilegal. En trabajos anteriores se determinó que sus poblaciones han sido afectadas debido al disturbio por la incidencia de actividades antrópicas que afectan su viabilidad. En la presente contribución se determina el nivel de riesgo de B. inermis con base en el Anexo Normativo II "Método de Evaluación de Riesgo de Extinción de Plantas en México". Se estudiaron 10 poblaciones de B. inermis en San Luis Potosí y Tamaulipas, tanto en áreas naturales protegidas como en sitios no protegidos. Los criterios MER considerados fueron: A) características de la distribución geográfica, B) características del hábitat, C) vulnerabilidad biológica intrínseca y D) impacto de la actividad humana. El análisis MER arroja un valor de 1.91 que, confirma a B. inermis dentro de la categoría de Amenazada. Las áreas naturales protegidas donde se distribuye la especie funcionan como núcleos de protección, sin embargo, su superficie puede no ser suficiente sin la presencia de corredores biológicos que las conecten.

Estimation of genetic variation in closely related cycad species in Ceratozamia (Zamiaceae: Cycadales) using rapds markers / Variación genética en especies de cícadas estrechamente relacionadas en Ceratozamia (Zamiaceae: Cycadales) mediante el uso de RAPDs

AbstractThe Ceratozamianorstogii complex from Southern Mexico is made up of four closely related taxa and occurs in similar habitats (Quercus forest). All have linear-lanceolate leaflets with great similarity between them, especially in juvenile stages, but differentiate with age. There has been debate regarding delimitation of species due to character loss in herbarium specimens. The aim of this study was to determine the genetic variation, and to measure genetic similarity between the four taxa. We studied populations in Cintalapa (Chiapas) for C. alvarezii and C. norstogii; the Sierra Atravesada (Oaxaca) for C. chimalapensis, and Villa Flores (Chiapas) for C. mirandae. One population for each taxon was sampled (only one population is known for C. alvarezii) 11-15 randomly chosen adult individuals were sampled. Twenty-eight primers were tested of which five were polymorphic using the RAPD'S technique. The data were analyzed using Bayesian methods. Results revealed low genetic diversity, and a differentiation was found between species, suggesting a recent divergence. A previous morphological and anatomical study on the complex has found the taxa to be distinct. However, the results of this study have shown that the C. norstogii species complex is in a divergence process, probably through genetic drift and founder effects. Rev. Biol. Trop. 65 (1): 305-319. Epub 2017 March 01.

ResumenLos cuatro taxa que componen el complejo Ceratozamia norstogii de especies en el sur de México están estrechamente relacionados y se dan en hábitats similares (bosque de Quercus). Todos tienen folíolos linear-lanceolados con gran similitud entre ellos, sobre todo en las etapas juveniles, pero se diferencian con la edad. Ha habido un debate en relación con la delimitación de especies debido a la pérdida de caracteres en especímenes de herbario. Los objetivos de este estudio son determinar la variación genética y medir la similitud genética entre los cuatro taxones en el complejo. Las poblaciones estudiadas están en; Cintalapa, Chiapas para C. alvarezii y C. norstogii, la Sierra Atravesada, Oaxaca para C. chimalapensis y Villa Flores, Chiapas para C. mirandae. Se tomaron muestras de una población de cada taxón (sólo una población es conocida para C. alvarezii) 11-15 individuos adultos elegidos al azar fueron muestreados. Veintiocho primers fueron probados, de los cuales cinco fueron polimórficos mediante la técnica RAPD's. Los datos fueron analizados utilizando métodos bayesianos. Los resultados revelaron baja diversidad genética y la diferenciación encontrada entre las especies sugiere una divergencia reciente. Un estudio morfológico y anatómico anterior en el complejo encontró que los taxa son distintos. Sin embargo, los resultados del presente estudio han demostrado que el complejo C. norstogii aun se encuentra en un proceso de divergencia, probablemente a través de deriva genética y efectos de fundador.

Antioxidant and antimutagenic activities of Mexican oregano (Lippia graveolens Kunth).

Free essential oil methanolic extracts from three different geographical populations of Lippia graveolens in México were screened for antioxidant and antimutagenic properties by the DPPH and Kado microsuspension assay, respectively. Total phenolic and flavonoid contents as well as HPLC identification and quantification of naringenin and rosmarinic acid were also carried out. In addition, a taxonomical phenetic analysis was performed. The L. graveolens extracts showed varying content of phenols and flavonoids. Significant concentration of rosmarinic acid was found for the first time in the species. All the extracts were capable of scavenging DPPH radicals in a concentration dependent fashion; the IC50 values correlate with the phenolic content. None of the extracts was toxic to TA100 and TA98 strains at the concentrations tested; moreover, the extracts at a concentration equivalent to 200 microg of gallic acid inhibited a 39 and 30% the mutagenicity induced by 4-nitro-o-phenylenediamine and sodium azide, respectively. The results suggest that the Mexican oregano is a source of polar bioactive ingredients for the food industry.