Protective Efficacy of the Antioxidants Vitamin E and Trolox AgainstMicrocystis aeruginosaand Microcystin-LR inArtemia franciscanaNauplii

Abstract

This study was undertaken to evaluate the protective efficacy of the antioxidants vitamin E and Trolox (a water-soluble vitamin E derivative) against the toxicity of microcystin-LR (MC-LR), Microcystis aeruginosa aqueous extract (CE), and a reference toxin, menadione sodium bisulfite (MSB), in Artemia franciscana nauplii. This was achieved by using the well-established brine shrimp bioassay. The experiment was conducted in 2 stages, with (1) 12-h mortality time course and (2) LC50 determination for 12- and 24-h exposures. Treatments consisted of MC-LR, CE, and MSB alone and with 4-h pretreatments of either vitamin E or Trolox. Sensitivity of A. franciscana nauplii with 24-h LC50 values of 11 (10.1-12.1) microg/ml for MSB and 9.5 (8.8-10.4) microg/ml for MC-LR were in general agreement with values reported for Artemia sp. Both antioxidant pretreatments resulted in significant reductions in mortality of approximately 50% at 9 h postexposure when challenged by either 40 microg/ml MC-LR or 20 microg/ml MSB. In contrast, the antioxidant pretreatments offered little to no protection from CE, suggesting that other uncharacterized bioactive compounds contributed to overall toxicity. The described bioassay is easily accessible, inexpensive, rapid, and complies with animal ethics guidelines of many countries, and thus provides a potential alternative to the mouse bioassay for the initial screening for chemoprotectants against MC-LR toxicity.

Antimicrobial activity and toxicity of Syzygium australe and Syzygium leuhmannii fruit extracts

“…[26][27][28][29] Briefly, 400 µl of seawater containing approximately 48 (mean 47.8, n = 125, SD 17.4) A. franciscana nauplii were added to wells of a 48 well plate and immediately used for bioassay. 400 µl of diluted plant extracts and the reference toxins were transferred to the wells and incubated at 25 ± 1 o C under artificial light (1000 Lux).…”

Duboisia leichhardtii (F.Muell.) Extracts Inhibit The Growth of Bacterial Triggers of Selected Autoimmune Inflammatory Diseases

“…[27][28][29] Briefly, 400 µL of seawater containing approximately 55 (mean 55.2, n = 125, SD 14.5) A. franciscana nauplii were added to wells of a 48 well plate and immediately used for bioassay. A volume of 400 µL of diluted plant extracts or the reference toxin were transferred to the wells and incubated at 25 ± 1 o C under artificial light (1000 Lux).…”

The potential of tasmannia lanceolata as a natural preservative and medicinal agent: antimicrobial activity and toxicity

“…[34][35][36][37] Briefly, 400 µl of seawater containing approximately 48 (mean 47.8, n = 125, SD 17.4) A. franciscana nauplii were added to wells of a 48 well plate and immediately used for bioassay. 400 µl of diluted plant extracts and the reference toxins were transferred to the wells and incubated at 25 ± 1 o C under artificial light (1000 Lux).…”