This study is aimed at assessing atmospheric deposition of heavy metals using the epiphytic moss genera Fabronia ciliaris collected from six urban sites in the Metropolitan Zone of the Toluca Valley in Mexico. The concentrations of K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, Rb, Sr, and Pb were determined by total reflection X-ray fluorescence technique. Results show that the average metal concentration decrease in the following order: Fe (8207 mg/Kg) > Ca (7315 mg/Kg) > K (3842 mg/Kg) > Ti (387 mg/Kg) > Mn, Zn (191 mg/Kg) > Sr (71 mg/Kg) > Pb (59 mg/Kg) > Cu, V (32 mg/Kg) > Cr (24 mg/Kg) > Rb (13 mg/Kg) > Ni (10 mg/Kg). Enrichment factors show a high enrichment for Cr, Cu, Zn, and Pb which provides an evidence of anthropogenic impact in the industrial and urban areas, mainly due to the intense vehicular traffic and the fossil fuel combustion. Monitoring techniques in mosses have proved to be a powerful tool for determining the deposition of heavy metals coming from diverse point sources of pollution.
The metropolitan area of the Toluca Valley (MATV) extends over an area of 1208.55 km2 and has 1,361,500 inhabitants making it the fifth highest populated area in the country and the second highest in the state. The MATV has several environmental problems, with regards to the air quality. Particles PM10 and PM2.5 are considered to be the main pollutant due to these particles frequently exceeding the limit laid down in the standards of the air quality in the country. For this reason, samples of the mosses Fabriona ciliaris and Leskea angustata were collected at different sites in MATV, Mexico in order to establish the atmospheric deposition of heavy metals by means of the analysis of the mosses tissues. Results show the average metal concentrations in the mosses in the order of: Zn > Pb > Cr > Cd. The concentration capacities of heavy metals were higher in Fabriona ciliaris than Leskea angustata. Enrichment factors for Cr, Zn, Pb and Cd were obtained using the soils from the same sampling area. Enrichment factors results show that Cr is conservative in both sampling seasons with a terrigenous origin; Zn is moderately enriched in both sampling seasons and mainly associated to pedological-soil or substrate contribution and anthropogenic activities and Cd is highly enriched in the rainy season and Pb is highly enriched in both sampling seasons, with a predominantly anthropogenic origin. This study provides information to be considered in the strategies for similar environmental problems in the world.
Shake-flask in vitro culture of Buddleja cordata cells produces large amounts of biomass and synthetizes verbascoside (VB), linarin and hydroxycinnamic acids, bioactive phenolic secondary metabolites (PSMs). In this work, we determined the effect of stirring speed on the growth of and production of PSMs [total phenolic, phenylethanoid glycoside and flavonoid contents (PeC, PeGC and FC, respectively)] by B. cordata cells cultured in two bioreactors. Two different stirring speeds (120 and 400 rpm) were tested in two stirred-tank bioreactors: a 2 L bioreactor equipped with a ring diffuser (B2RD) and a 3 L bioreactor with a sintered diffuser (B3SD). Growth kinetics of B. cordata cells were measured in the bioreactors and shake-flask systems. The stirring speed and type of bioreactor affected phases, parameters of growth and production of PSMs. The highest production of biomass (13.62 g L −1) and PSMs [PeC of 64.63 mg gallic acid equivalents g −1 (mg GAE g −1); PeGC of 119.24 mg VB equivalents g −1 (mg VBE g −1); and FC of 5.02 mg quercetin equivalents g −1 (mg QE g −1)] occurred in B2RD at 400 rpm. These values were similar to the found in shake-flasks system. This work establishes the basis for bioprocess advances of B. cordata focused on the development of a sustainable strategy for the management of natural resources and as a source of bioactive PSMs on a large scale. Key message Buddleja cordata cells cultured in a mechanically agitated bioreactor possess an outstanding biosynthetic potential that represents a suitable biotechnological alternative for the production of bioactive phenolic secondary metabolites. Keywords Bioreactor • Buddleja cordata • Phenolic secondary metabolites • Diffuser • Stirring speed • Verbascoside Abbreviations µ Specific growth rate ANOVA Analysis of variance B2RD 2 L Bioreactor equipped with a ring diffuser B3SD 3 L Bioreactor equipped with a sintered diffuser CSCBc Cell suspension culture of B. cordata CV Cellular viability Communicated by Sergio J. Ochatt.
The rural communities of Mexico take advantage of more than 500 species of edible plants. Among these vegetables are the quelites, which are defined as plants whose leaves, stems and flowers are consumed tender. Quelites have been part of Mexican diet since pre-Hispanic times, particularly among ethnic groups such as the Otomíes, also known as hñähñus. In order to analyze the floristic richness, use and management of the quelites in hñähñus population from the State of Mexico, free listings, semi-structured interviews and botanical collections were made in markets, milpas and forested areas adjacent to San Pedro Arriba town, Temoaya. Sixty-eight species and 5 varieties of quelites were registered, from 29 botanical families. Asteraceae, Amaranthaceae, Apiaceae and Brassicaceae stood out because they presented more than four species. The use of quelites with herbaceous habit (89%) and developed in terrestrial habitats (88%) predominated. Thirty-seven species and a variety are Mexican native plants, the rest are introduced species and only Sicyos microphyllus (Chayotillo) is endemic to Mexico. All species of quelites are incorporated into the diet, especially cooked (72%). Twenty-eight species are also used as medicinal plants, especially for digestive and respiratory diseases. The quelites with the highest values of use, importance and intensity of handling were Chenopodium berlandieri, C. berlandieri var. nuttaliae, Brassica rapa and Medicago polymorpha. Wild plant collections were the main form of management (30%). The acquisition of knowledge is mainly at a very young age (6 to 12 years) and its protection is especially maintained in women between 23 and 55 years (69%). The use and consumption of quelites by the Otomí community from San Pedro Arriba is extensive and must be promoted, documented and applied before globalization processes lead to their extinction and to the species that support them.
Arnica montana cell suspension culture could be a sustainable source of a vegetal material producer of secondary metabolites (SMs) possessing biological effects. Different plant growth regulator concentrations (0–5 mg/L) were tested in foliar explants to induce a callus that was used to establish a cell suspension culture. Growth kinetics was carried out for 30 days. A methanolic extract obtained from biomass harvested at 30 days of growth kinetics was fractionated, and three fractions were tested for bioactivities. We induced a callus with 1 mg/L of picloram and 0.5 mg/L of kinetin in foliar explants, which allowed for the establishment of a cell suspension culture, and the latter had the highest total SMs contents at day 30. Three fractions showed differences in total SMs contents, with the highest values per gram as follows: 270 mg gallic acid equivalent for total phenolic content, 200 mg quercetin equivalent for total flavonoid content, 83 mg verbascoside equivalent for total phenolic acid content, and 396 mg parthenolide equivalent for total sesquiterpene lactone content. The best bioactivities were 2–6 µg/mL for the 50% inhibition of 2,2-diphenyl-1-picrylhydrazyl radical, 30% cellular viability of lymphoma cells at 40 µg/mL, 17% inhibition against Escherichia coli and Staphylococcus aureus at 8 µg/disk, and α-amylase inhibition at 12% with 10 µg/mL. The total SMs contents were correlated with bioactivities.
Los bosques de oyamel (Abies religiosa) del centro de México han estado sometidos a fuertes presiones humanas y la información sobre su riqueza y la afinidad geográfica de su flora en algunas regiones ha sido poco estudiada. Mediante recorridos de campo y colectas de ejemplares botánicos, se determinó la composición florística y los patrones de distribución geográfica actual de las familias, géneros y especies de un bosque de oyamel localizado en la Faja Volcánica Transmexicana. Se obtuvo una lista de 94 especies agrupadas en 74 géneros y 42 familias. El 67 % de la flora se concentra en 13 familias de las que Asteraceae destaca por contener el mayor número de especies (24,5 %) y géneros (22 %). La similitud florística entre la zona de estudio y bosques vecinos se incrementa con la cercanía geográfica. El 60 % de las familias son de amplia distribución y cerca del 50 % de los géneros son americanos distribuidos principalmente de México a Centroamérica. El 95,8 % de las especies son exclusivas de América, de las cuales el 44,2 % se encuentran solo en los límites de México y 36,8 % se distribuyen de México a Centroamérica. Entre las especies arbóreas predominan los elementos distribuidos de México a Centroamérica (61,4 %), mientras que entre los arbustos y hierbas sobresalen las especies endémicas de México (60 % y 43,6 %, respectivamente). La alta proporción de especies endémicas de la zona analizada demandan monitoreo continuo que garantice la generación de nuevas alternativas para su conservación.
Resumen. La riqueza y abundancia de briofitas en espacios urbanos puede ser un indicador de calidad del ambiente. En México los estudios sobre la diversidad briológica de áreas urbanas y su uso en el monitoreo ambiental son escasos. En este estudio se identificó la riqueza de musgos epifitos de la zona metropolitana del valle de Toluca (ZMVT) a partir de la recolecta de todas las especies. Adicionalmente, las colonias de musgos se muestrearon por el método en parcela, para determinar las variaciones de su diversidad en 16 zonas verdes. Se encontró una riqueza de 41 especies y variedades incluidas en 16 familias: la familia Pottiaceae fue la más numerosa y frecuente. El 65% de las especies tienen una distribución geográfica amplia. Los estimadores Jacknife 1 y bootstrap indican que el inventario presenta entre el 71 y 85% de los taxones esperados. Las colonias de musgos epifitos tienden a ser diversas (H= 2.3) y están representadas en orden de importancia por Syntrichia amphidiacea, Leskea angustata, Syntrichia fragilis, Syntrichia pagorum y Fabronia ciliaris, que fueron las especies con mayor peso ecológico. Las zonas verdes analizadas presentan baja similitud promedio (ISj= 0.30) asociada potencialmente a las condiciones microclimáticas y a su cercanía a los centros urbanos.Palabras clave: riqueza, abundancia, briofitas, zonas urbanas.
4 Autora para la correspondencia: zepedac@uaemex.mx RESUMEN Las ciénegas de Lerma o de Chignahuapan, Chimaliapan y Chiconahuapan son áreas naturales protegidas, importantes para la conservación de aves y una de las regiones hidrológicas prioritarias, amenazadas y con alta diversidad biológica en México. No obstante, hay poca información actualizada sobre su vegetación, aun cuando están en franco peligro de desaparecer. En este estudio se identificó la flora vascular acuática y las variaciones de la diversidad vegetal de los tres cuerpos de agua, a partir de la colecta de todas las especies presentes; adicionalmente se aplicó el método de la línea intercepto en 20 a 40 sitios de cada cuerpo de agua. Se encontró una riqueza florística de 97 especies de plantas vasculares incluidas en 39 familias y 65 géneros. De los elementos registrados 46% fueron acuáticos estrictos, 31% subacuáticos y 20% tolerantes. Las familias Cyperaceae, Asteraceae, Lemnaceae, Poaceae, Apiaceae y Polygonaceae fueron las mejor representadas. La diversidad de las ciénegas de Lerma es relativamente alta (índice de Shannon = 3.2) y presenta variaciones particulares en cada humedal. Chiconahuapan muestra los valores más altos y proporciona heterogeneidad florística a los humedales. La prevalencia de malezas terrestres y acuáticas sugiere un deterioro continuo de estos hábitats; sin embargo, la presencia de especies características de áreas lacustres y de distribución restringida indica que las ciénegas aún poseen una diversidad vegetal significativa. Desafortunadamente estos sistemas están sujetos a cambios negativos drásticos e irreversibles, si las condiciones de perturbación, contaminación y disminución del nivel de agua no se revierten.
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