Bioluminescence-based assays for assessing antibacterial properties of medicinal plants

Extended research has been carried out to clarify the ecological role of plant secondary metabolites (SMs). Although their primary ecological function is self-defence, bioactive compounds have long been used in alternative medicine or in biological control of pests. One single plant may contain a wide variety of bioactive compounds, making analytics rather costly. The total bactericide capacity can be quantified by either microbiological or ecotoxicological methods. Here, the principle and possible applications of a specific bacterial bioluminescence inhibition based ecotoxicological assay are reviewed

Spread and distribution pattern of Sinanodonta woodianain Lake Balaton

The exotic Chinese pond mussel (Sinanodonta woodiana) is the biggest bivalve in Europe, it was first reported from Lake Balaton in 2006. In 2011 summer relative abundance and biomass of S. woodiana and native unionids were recorded at 21 sampling sites, in order to analyse the speed of dispersion of the Chinese pond mussel and to reveal its possible ecological impacts on native unionids. GPS coordinates of the sampling sites were recorded, spatial distribution of the data shows that high abundances and biomass are characteristic along the northern shore of the lake. In the western part of the lake, in the Keszthely Basin, its biomass may amount to as much as 50–80% of the total unionid biomass. In this basin, comparing these data to the distribution of unionids measured in 1992/93, the impact of S. woodiana seems high, as A. cygnea has been replaced by S. woodiana and the ratio of A. anatina reduced from 17.8% to 8.6%. Taking into consideration that S. woodiana has so rapidly developed high relative abundance and biomass close to the supposed source of introduction and it has a high spread potential in the lake, future increase in population size (and dominance) can be expected

Nanosegregation in Na2C60

There is continuous interest in the nature of alkali metal fullerides containing C(4)(60) and C(2)(60), because these compounds are believed to be nonmagnetic Mott–Jahn–Teller insulators. This idea could be verified in the case of A(4)C(60), but Na(2)C(60) is more controversial. By comparing the results of infrared spectroscopy and X-ray diffraction, we found that Na(2)C(60) is segregated into 3-10 nm large regions. The two main phases of the material are insulating C(60) and metallic Na(3)C(60). We found by neutron scattering that the diffusion of sodium ions becomes faster on heating. Above 470 K Na(2)C(60) is homogeneous and we show IR spectroscopic evidence of a Jahn–Teller distorted C(2)(60) anion

Sensitivity of three unionid glochidia to elevated levels of copper, zinc and lead

In this study glochidia as most sensitive life-stage of bivalves were used to evaluate the toxicity of copper, zinc and lead. Sensitivity of three species, Anodonta anatina, Pseudanodonta complanata and Unio tumiduswere compared to copper and zinc, based on 24 and 48 h LC50s. The copper 24 h LC50 showed the lowest value (26.8 μg·L-1) for Unio tumidus glochidia. After 48 h exposure, close LC50 values, 18.9 and 19.0 μg·L-1, were recorded for A. anatina and U. tumidus glochidia, respectively. U. tumidus glochidia exhibited the highest sensitivity to zinc (48 h LC50 = 134.2 μg·L-1) followed by P. complanata (48 h LC50 = 201.6 μg·L-1) and A. anatina (48 h LC50 = 233.5 μg·L-1). Toxicity of lead to P. complanata glochidia was estimated, 24 and 48 h LC50s of lead to 374.6 and 260.8 μg·L-1, respectively. No observed effect concentrations (NOECs) for the tested metals exhibited species differences. All NOECs exceeded environmental quality standards (EQS), therefore these species are at risk only in such European freshwaters which have extreme concentration of these metals. Synergistic effect was reported for the combinations of Cu + Zn and Cu + Pb, additive effect was reported for Zn + Pb

Sensitivity of three unionid glochidia to elevated levels of copper, zinc and lead

In this study glochidia as most sensitive life-stage of bivalves were used to evaluate the toxicity of copper, zinc and lead. Sensitivity of three species, Anodonta anatina, Pseudanodonta complanata and Unio tumiduswere compared to copper and zinc, based on 24 and 48 h LC50s. The copper 24 h LC50 showed the lowest value (26.8 μg·L-1) for Unio tumidus glochidia. After 48 h exposure, close LC50 values, 18.9 and 19.0 μg·L-1, were recorded for A. anatina and U. tumidus glochidia, respectively. U. tumidus glochidia exhibited the highest sensitivity to zinc (48 h LC50 = 134.2 μg·L-1) followed by P. complanata (48 h LC50 = 201.6 μg·L-1) and A. anatina (48 h LC50 = 233.5 μg·L-1). Toxicity of lead to P. complanata glochidia was estimated, 24 and 48 h LC50s of lead to 374.6 and 260.8 μg·L-1, respectively. No observed effect concentrations (NOECs) for the tested metals exhibited species differences. All NOECs exceeded environmental quality standards (EQS), therefore these species are at risk only in such European freshwaters which have extreme concentration of these metals. Synergistic effect was reported for the combinations of Cu + Zn and Cu + Pb, additive effect was reported for Zn + Pb

Quantification of the antibacterial properties of Artemisia absinthium, A. vulgaris, Chrysanthemum leucanthemum and Achillea millefolium using the Vibrio fischeri bacterial bioassay

Extended research has been carried out on the antimicrobial properties of herbs belonging to the family Asteraceae, trying to establish their potential use in natural pest control, in addition to human medicinal applications. For testing and quantifying antibacterial activity, most often standard microbial protocols are used. In this study the aggregate bactericide effect of four species ( Artemisia absinthium L., A. vulgaris L., Chrysanthemum leucanthemum L. and Achillea millefolium L.) was screened using the Vibrio fischeri bioluminescence inhibition bioassay. The two Artemisia species which have well-established use as antibacterial, exerted the highest toxicity. Toxicity of Chrysanthemum leucanthemum fell into the same range, although this herb has restricted use in human medicine. On the contrary, Achillea millefolium , which is widely recommended against inflammations, showed significantly lower toxicity

A novel protocol for assessing aquatic pollution, based on the feeding inhibition of Daphnia magna

In this study, sensitivity of a novel acute bioassay based on the feeding activity of Daphnia magna was assessed, using 2 and 4 h of exposure. For calibration purposes, results were compared with those of the standard immobility test as described by the ISO 6341:1996 standard. Using potassium dichromate as the reference chemical, after 4 h of exposure the proposed protocol showed similar sensitivity in comparison with the standard, as the EC50 of the immobility test was 1.093 ± 0.098 mg·L–1, whereas the EC50 of the feeding inhibition bioassay was 1.742 ± 0.133 mg·L–1. In order to test the sensitivity of the bioassay, toxicity of two other contaminants, copper and wastewater, was estimated and the results were compared with those of the standard immobility test. For both cases, the feeding inhibition test showed higher sensitivity, as in the case of copper the EC50s were 0.0952 ± 0.0087 and 0.0753 ± 0.0152 mg·L–1, whilst the EC50 recorded for the 24-h immobility test was 0.2407 ± 0.0159 mg·L–1. In the case of the effluent, EC50 values after 2 and 4 h of exposure were 15.698 ± 2.681 and 12.557 ± 2.358 expressed as % of the wastewater, respectively, whereas the EC50 of the immobility test was calculated to be 36.4688 ± 5.4887