Glyphosate-based herbicide induces long-lasting impairment in neuronal and glial differentiation.

Glyphosate-based herbicides (GBH) are among the most sold pesticides in the world. There are several formulations based on the active ingredient glyphosate (GLY) used along with other chemicals to improve the absorption and penetration in plants. The final composition of commercial GBH may modify GLY toxicological profile, potentially enhancing its neurotoxic properties. The developing nervous system is particularly susceptible to insults occurring during the early phases of development, and exposure to chemicals in this period may lead to persistent impairments on neurogenesis and differentiation. The aim of this study was to evaluate the long-lasting effects of a sub-cytotoxic concentration, 2.5 parts per million of GBH and GLY, on the differentiation of human neuroepithelial stem cells (NES) derived from induced pluripotent stem cells (iPSC). We treated NES cells with each compound and evaluated the effects on key cellular processes, such as proliferation and differentiation in daughter cells never directly exposed to the toxicants. We found that GBH induced a more immature neuronal profile associated to increased PAX6, NESTIN and DCX expression, and a shift in the differentiation process toward glial cell fate at the expense of mature neurons, as shown by an increase in the glial markers GFAP, GLT1, GLAST and a decrease in MAP2. Such alterations were associated to dysregulation of key genes critically involved in neurogenesis, including PAX6, HES1, HES5, and DDK1. Altogether, the data indicate that subtoxic concentrations of GBH, but not of GLY, induce long-lasting impairments on the differentiation potential of NES cells.

Analyzing the toxicity of bisphenol-A to microalgae for ecotoxicological applications.

Bisphenol-A (BPA) is a chemical used in the production of polycarbonate plastic and epoxy resins that may be related to the occurrence of human endocrine disorders. The present study aims to indicate a microalgae for use in ecotoxicological tests concerning BPA contamination of aquatic environments by analyzing its toxicity for the freshwater species Pseudokirchneriella subcapitata, and the two marine species Tetraselmis chuii and Skeletonema costatum. The standardization of the test involved determination of suitable nominal concentrations of BPA and the most appropriate species for use as biomarkers. S. costatum and P. subcapitata demonstrated resistance to BPA, features that are not of interest for toxicity markers. T. chuii presented an adequate sensitivity to BPA, compatible with parameters used in human toxicology for this substance, and is indicated as a potential biomarker for the presence of BPA in marine environments. The IC50 of T. chuii was 2.5 µM with R2 = 0.9, indicating reliability to demonstrate that low concentrations of BPA has significant toxicity to this species.

Production and characterization of Spirulina sp. LEB 18 cultured in reused Zarrouk's medium in a raceway-type bioreactor.

The objective was to evaluate the effect of reusing Zarrouk's medium on a Spirulina sp. LEB 18 culture by determining kinetic parameters, chemical composition, biofuels, and thermal characterization. Cultivation was performed in a raceway bioreactor for 7 days, the supernatant was reused for four cycles. Culturing the microalga in the reused medium resulted in a cellular yield of 2.30 g L-1 (control) and 2.04, 1.89, 1.73, and 1.15 g L-1 for four cycles with no influence on cell growth and productivity. Biomass with high contents of carbohydrates (58.00%, 3rd cycle), phycocyanin (2.47 mg mL-1, 1st cycle), and saturated fatty acids (60.13%, 4th cycle) were obtained with an increase in the profiles of C16:0 (45.85%) and C18:2n6 (47.40%) in the 1st cycle. The reuse of Zarrouk's medium allowed obtaining biomass with reduced cost and differentiated characteristics, allowing the exploration of commercially important biomolecules by the completion of up to four cycles.

Estrogen and Thyroid Hormone Receptor Activation by Medicinal Plants from Bahia, Brazil.

Background: A number of medicinal plants are traditionally used for metabolic disorders in Bahia state, Brazil. The aim of this study was to evaluate the estrogen receptor (ER) and thyroid receptor (TR) activation of crude extracts prepared from 20 plants. Methods: Species were extracted and assayed for receptor activation through both ER and TR gene-reporter assays, using 17ß-estradiol and triiodothyronine (T3), respectively, as the positive controls. Results: Cajanus cajan (Fabaceae), Abarema cochliacarpus (Fabaceae), and Borreria verticillata (Rubiaceae) were able to activate ER as much as the positive control (17ß-estradiol). These three plant species were also assayed for TR activation. At the concentration of 50 µg/mL, C. cajans exerted the highest positive modulation on TR, causing an activation of 59.9%, while B. verticillata and A. cochliacarpus caused 30.8% and 23.3%, respectively. Conclusions: Our results contribute towards the validation of the traditional use of C. cajans, B. verticillata, and A. cochliacarpus in the treatment of metabolic disorders related to ER and TR functions. The gene-reporter assay was proven effective in screening crude plant extracts for ER/TR activation, endorsing this methodology as an important tool for future bioprospection studies focused on identifying novel starting molecules for the development of estrogen and thyroid agonists.