Critical Evaluation of Specific Efficacy of Preparations Produced According to European Pharmacopeia Monograph 2371.

European Pharmacopoeia monograph 2371 describes the production of homeopathic preparations. A specific efficacy of these preparations in high dilution levels is questionable in view of basic scientific principles. There is empirical evidence for such effects, for example in a Lemna-intoxication bioassay published 2010. To test the replicability and robustness of this bioassay, we conducted two experimental series (five independent blinded and randomised experiments each). The specimen of Lemna gibba L., clone-number 9352, were stressed in arsenic solution for 48 h (158 mg/L AsNa2HO4 (250 mg/L in series 2)), then grew in either As2O3 preparations produced according to Eu. Pharm. Monogr. 2371 or control solution. Comparing the area-related relative growth rate of day 3-9 (rgr 3-9) between treatment and control groups for each series showed differences that were not significant in series 1 (p = 0.10), significant in series 2 (p = 0.04) and significant in the pooled data of both series (p < 0.01). The effect direction (rgr 3-9 increase) was comparable to experiments of 2010, but the effect size was smaller, likely due to a changed light cycle. These results are not compatible with the hypothesis that the application of European Pharmacopoeia monograph 2371 results in pharmaceutical preparations without specific effects. Further studies are needed to investigate a potential mode of action explaining these effects

Test System Stability and Natural Variability of a Lemna Gibba L. Bioassay

BACKGROUND: In ecotoxicological and environmental studies Lemna spp. are used as test organisms due to their small size, rapid predominantly vegetative reproduction, easy handling and high sensitivity to various chemicals. However, there is not much information available concerning spatial and temporal stability of experimental set-ups used for Lemna bioassays, though this is essential for interpretation and reliability of results. We therefore investigated stability and natural variability of a Lemna gibba bioassay assessing area-related and frond number-related growth rates under controlled laboratory conditions over about one year. METHODOLOGY/PRINCIPAL FINDINGS: Lemna gibba L. was grown in beakers with Steinberg medium for one week. Area-related and frond number-related growth rates (r(area) and r(num)) were determined with a non-destructive image processing system. To assess inter-experimental stability, 35 independent experiments were performed with 10 beakers each in the course of one year. We observed changes in growth rates by a factor of two over time. These did not correlate well with temperature or relative humidity in the growth chamber. In order to assess intra-experimental stability, we analysed six systematic negative control experiments (nontoxicant tests) with 96 replicate beakers each. Evaluation showed that the chosen experimental set-up was stable and did not produce false positive results. The coefficient of variation was lower for r(area) (2.99%) than for r(num) (4.27%). CONCLUSIONS/SIGNIFICANCE: It is hypothesised that the variations in growth rates over time under controlled conditions are partly due to endogenic periodicities in Lemna gibba. The relevance of these variations for toxicity investigations should be investigated more closely. Area-related growth rate seems to be more precise as non-destructive calculation parameter than number-related growth rate. Furthermore, we propose two new validity criteria for Lemna gibba bioassays: variability of average specific and section-by-section segmented growth rate, complementary to average specific growth rate as the only validity criterion existing in guidelines for duckweed bioassays

Arsenic accumulation in duckweed (Spirodela polyrhiza L.): A good option for phytoremediation

Some unavoidable drawbacks of traditional technologies have made phytoremediation a promising alternative for removal of arsenic from contaminated soil and water. In the present study, the potential of an aquatic macrophyte Spirodela polyrhiza L. for phytofiltration of arsenic, and the mechanism of the arsenic uptake were investigated. The S. polyrhiza L. were grown in three test concentrations of arsenate and dimethylarsinic acid (DMAA) (i.e. 1.0, 2.0 and 4.0 μM) with 0 (control), 100 or 500 μM of phosphate. One control treatment was also set for each test concentrations of arsenic. The PO43 - concentration in control treatment was 0.02 μM. When S. polyrhiza L. was cultivated hydroponically for 6 d in culture solution containing 0.02 μM phosphate and 4.0 μM arsenate or DMAA, the arsenic uptake was 0.353 ± 0.003 μmol g-1 and 7.65 ± 0.27 nmol g-1, respectively. Arsenic uptake into S. polyrhiza L. was negatively (p 0.05) with iron accumulation in plant tissues, which indicates that S. polyrhiza L. uses different mechanisms for DMAA uptake. © 2007 Elsevier Ltd. All rights reserved

Arsenic uptake by aquatic macrophyte Spirodela polyrhiza L.: Interactions with phosphate and iron

The uptake of arsenate (As(V)) and dimethylarsinic acid (DMAA) by aquatic macrophyte Spirodela polyrhiza L. was investigated to determine the influence of arsenic interaction with PO43- and Fe ions. Plants were grown hydroponically on standard Murashige and Skoog (MS) culture solutions. Arsenic concentrations in Fe-oxide (Fe-plaque) on plant surfaces were determined by citrate-bicarbonate-ethylenediaminetetraacetic acid (CBE) technique. S. polyrhiza L. accumulated 51-fold arsenic from arsenate solution compared to that from DMAA solution with initial concentrations of 4.0 and 0.02 μM of arsenic and phosphate, respectively. The arsenate uptake was negatively (p 0.05) with iron accumulation. The results suggest that adsorption of arsenate on Fe-plaque of the surface of S. polyrhiza L. contributes to the arsenic uptake significantly. Thus, arsenate uptake in S. polyrhiza L. occurred through the phosphate uptake pathway and by physico-chemical adsorption on Fe-plaques of plant surfaces as well. The S. polyrhiza L. uses different mechanisms for DMAA uptake. © 2008 Elsevier B.V. All rights reserved

Influence of phosphate and iron ions in selective uptake of arsenic species by water fern (Salvinia natans L.)

In the present study, the effect of phosphate ion and iron hydroxides (Fe-plaques) on the selective uptake of arsenic species by water fern (Salvinia natans L.) was investigated. The plants were grown for 5 days in aqueous Murashige and Skoog (MS) culture media modified in arsenic and phosphate concentrations. Arsenic accumulations in S. natans L. increased with the increase of arsenate and DMAA concentrations in the culture solutions. Compared to the control treatment, S. natans L. accumulated significantly higher amount of arsenic from phosphate-deficient solutions, when the source was arsenate. However, arsenic uptake was not affected significantly by phosphate, when the source was dimethylarsinic acid (DMAA). From solutions containing 100 μM of phosphate and 4.0 μM of either arsenate or DMAA, the S. natans L. accumulated 0.14 ± 0.02 and 0.02 ± 0.00 μmol (g dry weight)-1 of arsenic, respectively. In contrast, plants accumulated 0.24 ± 0.06 and 0.03 ± 0.00 μmol (g dry weight)-1 of arsenic from solutions containing 4.0 μM of either arsenate and DMAA in phosphate deficient conditions, respectively. Thus, it is reasonable to state that increasing phosphate concentration in culture solutions decreased the arsenic uptake into the water fern significantly, when the source was arsenate. Moreover, arsenic and phosphate content in plant tissue correlated significantly (r = -0.66; p 0.05). Similarly, significant correlation was observed between arsenic and iron content in plant tissues (r = 0.66; p < 0.05), when initial source was arsenate while the correlation was not significant (r = 0.23; p < 0.05), when initial source was DMAA. The results indicate the adsorption of arsenate on Fe-plaques of aquatic plant surfaces. Furthermore, the study demonstrates that the DMAA uptake mechanisms into the water fern are deferent from those of arsenate. © 2008 Elsevier B.V. All rights reserved

Contribución al estudio de las Lemnáceas de Huelva (Andalucía occidental, España)

La superficie de humedales presentes en Huelva concentra la mayor proporción de zonas húmedas de Andalucía con 54.825 ha de superfi cie palustre (77,39%). Esta riqueza y diversidad de medios acuáticos posibilitan la localización de numerosas plantas acuáticas y la conservación de humedales tan emblemáticos como el Parque Nacional de Doñana, el Paraje Natural Marismas del Odiel, o las Turberas de Las Madres. Se estudian 7 Lemnáceas presentes en la provincia de Huelva (Andalucía Occidental, España), citándose como novedad regional para Andalucía Lemna valdiviana Phil., especie americana naturalizada en diversos puntos de la Península Ibérica. Se estudia la distribución de este grupo de macrófi tos en la provincia, y se amplía la distribución conocida de Wolffi a arrhiza (L.) Horkel ex Wimm., Lemna trisulca L., y Spirodela polyrrhiza (L.) Schleind., especies amenazadas en España.The main dimension of humid areas in Andalucia are present in Huelva province with 54.825 ha (77,39%). This richness and diversity in aquatic environments make possible the location of numerous aquatic plants, and the conservation of emblematic wetlands as Parque Nacional de Doñana, Paraje Natural Marismas del Odiel or Turberas de Las Madres. The distribution of 7 species of the Duckweed Family, present in the Huelva province (Occidental Andalusia, Spain), are studied. Lemna valdiviana Phil., an American species, is presented as a regional novelty for the Andalusian fl ora, and the known distribution of Wolffi a arrhiza (L.) Horkel ex Wimm., Lemna trisulca L. and Spirodela polyrrhiza (L.) Schleind., 3 threatened species from Spain, is extended.proyecto “Flora iberica VIII” CGL2008-02982-C03-01/CLI, Ministerio de Ciencia e Innovació

Adsorción de Metales Pesados a través de Carbón Activado a partir de Lemna gibba L. Puno, Perú – 2015

En este trabajo de investigación se utilizó la especie Lemna gibba L. que se desarrolla en el lago Titicaca, en la región de Puno, para la elaboración del Carbón Activado (CA). El proceso de obtención por activación química consistió en la impregnación de las muestras en proporciones de 1:1, previamente deshidratadas a 60 °C, durante un periodo de 72 horas, con ácido fosfórico como agente activante en concentraciones de 1 N, durante 24 horas, la carbonización en una mufla se basó en la calcinación de 1 hora a 500 °C. Las propiedades fisicoquímicas se estudiaron mediante mediciones de adsorción de metales pesados por espectrofotometría ICP - OES y microscopia electrónica de barrido. El carbón activado obtenido de la Lemna gibba L. presenta un diámetro ≤ 2.094 mm de partículas de mayor tamaño y diámetros ≥150.5 μm de partículas de menor tamaño. El grado de porosidad presenta entre 10.48 μm y 125.3 μm de diámetro longitudinal del poro. Se tomaron muestras de agua superficial en el área de estudio de la zona minera ubicada en el distrito de Ananea, provincia de San Antonio de Putina, Puno, Perú. (4610 msnm 14°40´40´´ LS y 69°31´56´´ LW). Donde se utilizaron los carbones activados para la adsorción de metales pesados: Cobre, Hierro, Mercurio, Arsénico, Níquel, cromo cadmio, plomo y zinc. Donde la capacidad de adsorción se desarrolló en dos pruebas analíticas a nivel del laboratorio, el mercurio (Hg) fue adsorbido en un 99.34% en ambos métodos (método columna de adsorción y remoción por agitación magnética), el hierro (Fe) fue adsorbido en un 97.62% por el método de remoción por Agitación Magnética (AM) y solo en un 85.48% por el método de columna de adsorción, El cobre (Cu) fue adsorbido en un 89.13% por el método de remoción por AM, y sin embargo solo 79.29% fue adsorbido por el método de columna de adsorción. Los factores más importantes que influyen en el proceso de adsorción fueron el pH de la solución, la estructura porosa y la acides superficial del carbón activado. Palabras claves: Carbón activado, metales pesados, adsorción, remoción, lenteja de agua

Influence of EDTA and chemical species on arsenic accumulation in Spirodela polyrhiza L. (duckweed)

The influence of ethylenediaminetetraacetic acid (EDTA) and chemical species on arsenic accumulation in aquatic floating macrophyte Spirodela polyrhiza L. (duckweed) was investigated. The uptake of inorganic arsenic species (arsenate; As(V) and arsenite; As(III)) into the plant tissue and their adsorption on iron plaque of plant surfaces were significantly (p0.05) by EDTA addition to the culture media while its concentration in CBE-extract decreased significantly (p<0.05). The As(inorganic)/Fe ratios in plant were higher than those of CBE-extract which indicate the increased uptake of these arsenic species into the plant relative to the iron. The lower As(organic)/Fe ratios in plant and on CBE-extract suggest the reduction of accumulation of these arsenic species relative to the iron. © 2007 Elsevier Inc. All rights reserved

The potential of Lemna gibba L. and Lemna minor L. to remove Cu, Pb, Zn, and As in gallery water in a mining area in Keban, Turkey

This study was designed to investigate removal efficiencies of Cu, Pb, Zn, and As in gallery water in a mining area in Keban, Turkey by Lemna gibba L. and Lemna minor L. These plants were placed in the gallery water of Keban PbeZn ore deposits and adapted individually fed to the reactors. During the study period (8 days), the plant and water samples were collected daily and the temperature, pH, and electric conductivity of the gallery water were measured daily. The plants were washed, dried, and burned at 300 C for 24 h in a drying oven. These ash and water samples were analyzed by ICP-MS to determine the amounts of Cu, Pb, Zn, and As. The Cu, Pb, Zn and As concentrations in the gallery water of the study area detected 67, 7.5, 7230, and 96 mg L 1, respectively. According to the results, the obtained efficiencies in L. minor L. and L. gibba L. are: 87% at day 2 and 36% at day 3 for Cu; 1259% at day 2 and 1015% at day 2 for Pb; 628% at day 3 and 382% at day 3 for Zn; and 7070% at day 3 and 19,709% at day 2 for As, respectively. The present study revealed that both L. minor L. and L. gibba L. had very high potential to remove Cu, Pb, Zn, and As in gallery water contaminated by different ores