Bioresilience to Mercury Chloride of the Brine Shrimp Artemia Salina after Treatment with Homeopathic Mercurius Corrosivus

Introduction Finding solutions to mitigate the impact of pollution on living systems is a matter of great interest. Homeopathic preparations of toxic substances have been described in the literature as attenuation factors for intoxication. Herein, an experimental study using Artemia salina and mercury chloride was developed as a model to identify aspects related to bioresilience. Aims The aim of the study was to describe the effects of homeopathic Mercurius corrosivus (MC) on Artemia salina cysts hatching and on mercury bioavailability. Methods Artemia salina cysts were exposed to 5.0 µg/mL of mercury chloride during the hatching phase. MC potencies (6cH, 30cH, and 200cH) were prepared in sterile purified water and poured into artificial sea water. Different controls were used (non-challenged cysts and challenged cysts treated with water, succussed water, and Ethilicum 1cH). Four series of nine experiments were performed to evaluate the percentage of cyst hatching. Soluble total mercury (THg) levels and precipitated mercury content were also evaluated. Solvatochromic dyes were used to check for eventual physicochemical markers of MC biological activity. Results Significant delay (p < 0.0001) in cyst hatching was observed only after treatment with MC 30cH, compared with controls. This result was associated with an increase of THg concentration in water (p = 0.0018) and of chlorine/oxygen ratio (p < 0.0001) in suspended micraggregates, suggesting changes in mercury bioavailability. A specific interaction of MC 30cH with the solvatochromic dye ET33 (p = 0.0017) was found. Conclusion Changes in hatching rate and possible changes in Hg bioavailability are postulated as protective effects of MC 30cH on Artemia salina, by improving its natural bioresilience processes.

Population growth and cyst production of the rotifer Brachionus plicatilis (Monogonta: Brachionidae) fed with three different diets

This study compares the effect of different diets on population growth, fecundity rate, production, and cyst hatching efficiency of the rotifer Brachionus plicatilis. Microalgae were cultured using filtered and sterilized seawater at 25 and 26ºC. The volume of the containers for algae, bread yeast, and rotifer was duplicated daily from 31mL to 16L in nine days. Rotifers were cultured at 25°C and 35o/oo salinity. The mean values of daily population growth rate for the rotifers fed on C. muelleri, I. galbana and bread yeast were 0,91, 0,89 and 0,87 daily counts, respectively. After 10 cultured days, fecundity was 72%, 63% and 36% using C. muelleri, I. galbana and bread yeast, respectively. The highest mean value for cysts production was 4 064 000 cysts found from 63 243 (1,55%) rotifers fed on C. muelleri. Hatching efficiency after 36 hours of cysts from rotifers fed C. muelleri was 51 500 (94,3%) new borns, followed by 45 000 (93,3%) with I. galbana, and 31 000 (92,6%) with bread yeast. C. muelleri is a good food source for B. plicatilis.KEY WORDSFecundity, feeding, hatching, salinity, temperature

Investigations on the Emergence of Larvae from Cysts of the Potato-Root Eelworm Heterodera rostochiensis 2. The Form of the Hatching Curve

Experiments were conducted in which single cysts and batches of 100 cysts were exposed to the action of potato-root diffusate and the number of larvae liberated at the end of certain intervals of time recorded. Investigation showed that when the hatch at the end of each time interval was expressed as a probit of the total hatch, and plotted against the logarithm of that time, a close approximation to linearity resulted. Statistical analysis confirmed this agreement in the case of single cyst hatching, but disclosed a significant degree of asymmetry in the case of multiple hatching. It was decided that the degree of curvature resulting from this when plotted as a probit line was sufficiently small for it to be ignored.