ABSTRACT
Different environmental conditions can influence the effects of toxic agents on living beings. Recently, a series of experiments performed in Artemia salina submitted to different kinds of intoxication have shown that both, isotherapic and succussed watercan change Artemia salina Ìs bio resilience at different levels. Moreover, it seems to vary according to the circalunar cycle. Objective:To verify if circalunar phases and water agitation can modify the toxicity of lead chloride on Artemia salina in vitro. Methodology:Artemia salina cysts were exposed to seawater containing 0.04% of lead chloride (equal to EC10 or 10% effective concentration, previously determined in a pilot study) in 96-well culture plates. Thirty-six experimental repetitions were performed in four series to observe the possible effects of adding stirred water, the so-called succussed water, and the moon phases. The hatched cysts were recorded after 48 hours using a digital microscope (1000x magnification) to identify the hatching percentage and the viability and mobility of the born nauplii. Results:The exposition of cysts to PbCl2 led to an increase in the hatching rate, and it was more evident during the full moon (p = 0.00014) The addition of succussed water into the seawater medium reduced this effect to the baseline levels. An increase in mobility was seen in nauplii born from exposed cysts during the full moon (p = 0.00077), but this effect was not affected by the treatment with succussed water. Discussion:Although the effects of lead chloride EC10 on the increase of nauplii hatching were expected, two environmental variables changed the sensitivity of cysts to this harmful stimulus. The circalunar cycle varied the hatching rate according to the moon phase, even in laboratory conditions, and the addition of succussed water into the medium reduced the hatching rate, even with different intensities according to the moon phase. The organization of nano and microbubbles generated after the succussion of water could be related to this protective effect and can explain, at least partially the effects of high diluted preparations on this biological context. Conclusion:Environmental factors, such as the circalunar cycle and products of water agitation, can modulate the adaptative control of hatching in Artemia salina exposed to lead chloride at EC10.
Subject(s)
Animals , Artemia , Chlorides/analysis , EcotoxicologyABSTRACT
Cyanobacteria are microorganisms found in different parts of the world. Some genera are cyanotoxins producers a sodium channel blockingneurotoxin (saxitoxins). Some homeopathic preparations have been identified as remedial action on toxicity models in Artemia salina. This study aimed to observe whether homeopathic products influence the toxicity ofR.raciborskiiextract onA.salinaby inducing cyst hatching arrest, anembryo bioresiliencemodel previously developed in our laboratory (Pinto et al., 2021; Mohammad et al., 2022). Thus, previous toxicity testswere carried out on cysts in 96-well plates, using different concentrations of the extract obtained from regular cultivation of R. raciborskii in HCl 0.05M, whose strain, named T3, is kept in the laboratory of Cyanobacteria at FURGS, Brazil.The standardization of toxin concentration was based on an established scale developed at FURGS, in which the number of T3 filaments is associated withspecific saxitoxin concentrationsdefined by chromatography. The concentration of 2.6 µg/L was chosen since it reducedthe cysthatching rate by 30%, the ideal level to observe embryo bioresilience. Then, a screeningstudy with 22 homeopathic preparations was tested blind in three experimental series, in duplicate,against threecontrols (unchallenged, water,and succussed water)for possible toxicity attenuationon Artemia salinacysts hatching rate. Homeopathic medicines were prepared in pure,sterile water from a stock homeopathic solution, one potency below the working potency. After the 1:100 dilution, 100 succussions were made using a robotic arm (Denise, Autic). The medicines were inserted into the seawater on a 10% basis. Due to the high sensitivity of A. salinato the circalunar variations, all experiments were performed during the first quarter moon. Statistical analysis was performed by two-way ANOVA followed by Tukey, with α=0.05. The most significant results indicative of bioresilience improvement were seen after the treatment with Nitric acidum6 cH, Plumbum metallicum6 cH, isotherapic 200 cH, and hydrochloric acid 1 cH being the last one used as a vehicle of the extracts. Thus, these preparations were chosen to be used in further experiments. In conclusion, the Artemia salinamodel has also beenuseful to study bioresilienceimprovement by homeopathic medicines after intoxication with saxitoxin.
Subject(s)
Artemia/virology , Biodegradation, Environmental , Homeopathic Vehicles , CyanobacteriaABSTRACT
Isotherapics preparedfromtoxic substances have been described as attenuation factors for heavy metal intoxicationin aquatic animals. Herein, Artemia salinaand mercury chloride were usedas a model to identify treatment-related bioresilience. The aim was to describe the effects of Mercurius corrosivus(MC) in different potencies on Artemia salinacyst hatching and on mercury bioavailability. Artemia salinacysts were exposed to 5.0 µg/mL of mercury chloride during the hatching phase. MC6cH, 30cH, and 200cHwere prepared and poured into artificial seawater. Different controls were used (nonchallenged cysts and challenged cysts treated with water, succussed water, and Ethilicum 1cH). Four series of nine experiments were performed for4 weeks to evaluate the percentage of cyst hatchingconsidering all moon phases. Soluble total mercury (THg) levels and precipitated mercury content were also evaluated. Solvatochromic dyes were used to check for eventual physicochemical markers of MCbiological activity. Two-way analysis of variance (ANOVA) with mixed modelswas used for evaluating the effect of different treatments andthe simultaneous influence of the moon phases on the cystshatching rate, at both observation times (24 and 48 hours).When necessary, outliers were removed, using the Tukeycriterion.Thelevel of significance αwas set at 5%. Significant delay (p<0.0001) in cyst hatching was observed after treatment with MC30cH, compared with the controls. An increase inTHg concentration in seawater (p<0.0018) and of chlorine/oxygen ratio (p<0.0001) in suspended micro-aggregateswas also seen, with possiblerelation with mercury bioavailability. Specific interaction of MC30cH with the solvatochromic dye ET33 (p<0.0017) was found. The other observed potencies of Mercurius corrosivus6 and 200 cH were not significant in relation to the observed groups.The results werepostulated as being protective effects of MC30cH on Artemia salina, by improving its bioresilience.