Impact of Iron Mining Activity on the Endophytic Fungal Community of Aspilia grazielae.

Aspilia grazielae (J. U. Santos) is an endemic plant species in Morro do Urucum in the Pantanal wetland (Brazil). A. grazielae is used for the restoration of areas impacted by iron mining activities. This study evaluates the diversity (composition, value and abundance) of endophytic fungal communities, considering parts of the plant and soil condition. The leaves and roots of A. grazielae were collected from native vegetation areas (NVA) and recovery areas (RCA) in Morro do Urucum. Illumina sequencing technology was used to investigate variation in endophytic fungal biodiversity. The operational taxonomic units detected in NVA ranged from 183 to 263 (leaf) and 115 to 285 (root), while RCA samples ranged from 200 to 282 (leaf) and 156 to 348 (root). Ascomycota phylum was the most common species among all plant samples. The most significant classes identified were Lecanoromycetes and Dothideomycetes that differed significantly (p ≤ 0.05) according to their plant hosts and soil stress. The relative abundance of Pestalotiopsis (Sordariomycetes class) and Stereocaulon (Lecanoromycetes class) genera was influenced by the iron mining activities according to the leaf samples analysed. However, the abundance and wealth of endophytic fungal communities in A. grazielae from RCA were evidence that could explain their high resilience to environmental disturbances and the source-sink dynamics of fungal propagules.

Osmoregulatory profiles and gill histological changes in Nile tilapia (Oreochromis niloticus) exposed to lambda-cyhalothrin.

Lambda-cyhalothrin is a synthetic pyrethroid that mimics the structure and insecticidal properties of pyrethrin, a natural insecticide derived from chrysanthemums. In fish, it disrupts the nervous system, causing motor paralysis and several other alterations associated with varying levels of mortality. This study aimed to evaluate osmoregulatory responses and histological changes in the gills of Oreochromis niloticus chronically exposed to a sublethal dosage (0.86 µg/L) of lambda-cyhalothrin. The mean serum values for Na2+, K+, Cl-, Ca2+, pH, lactate, H+, HCO3, and glucose along to degree of tissue change (DTC) at 24, 96, 168, and 240 h post-exposure (hpe) were evaluated. Lambda-cyhalothrin affected the neuronal motor function at 24 hpe, followed by the increase of the K+, Ca2+, H+, and glucose levels in the exposed group, compared to the control group. Lactate and H+ levels in the exposed group were higher than those in the control group at 168 and 240 hpe respectively. HCO3, and Cl- levels increased at 240 hpe, although there was no change in the pH values. DTC was higher in treated fish than in control fish, but there were no significant differences among time-exposure. The changes detected ranged from hyperemia of the branchial vasculature, eosinophilic granulocytic cell infiltration, mucous cell hyperplasia, and partial fusion of secondary lamellae at 24 hpe to vascular aneurysm formation, and necrosis of the lamellar epithelium at 240 hpe. Thus, a sublethal dosage of lambda-cyhalothrin in the long-term is toxic for Nile tilapia, characterized by hypokalemia, hypercalcemia, hyperglycemia, and respiratory alkalosis, followed by time-dependent histological changes.

Diaryl disulfides and thiosulfonates as combretastatin A-4 analogues: Synthesis, cytotoxicity and antitubulin activity.

Diaryl disulfides and diaryl thiosulfonates were synthesized with the two phenyl rings of all compounds bearing identical halide substituents. Because of structural similarity to the potent antimitotic natural product combretastatin A-4 (CA-4), the compounds were examined for inhibition of tubulin polymerization, and the thiosulfonates were more active than the disulfides. The nine thiosulfonates had IC50 values ranging from 1.2 to 9.1 µM, as compared with 1.3 µM obtained with CA-4. The compounds thus ranged from equipotent with CA-4 to 7-fold less active. The nine disulfides had IC50 values ranging from 1.2 to 5.1 µM, as compared with 0.54 µM obtained with CA-4. The compounds thus ranged from less than half as active as CA-4 to over 9-fold less active. The most active members of each group, 2 g and 3c, in the assembly assay were modeled into the colchicine site. Compound 3c had significant hydrophobic interactions with ß-tubulin residues CYS 241 and ALA 250, and its thiosulfonate bridge made a hydrogen bond with ß-tubulin residue ASN 258. Compound 2 g had hydrophobic interactions with ß-tubulin residues ALA 250, CYS 241 and ALA 254, but there was no significant interaction of the disulfide bridge with tubulin.

Adulteration and Contamination of Commercial Sap of Hymenaea Species.

The Hymenaea stigonocarpa and Hymenaea martiana species, commonly known as "jatobá," produce a sap which is extracted by perforation of the trunk and is commonly used in folk medicine as a tonic. For this study, the authenticity of commercial samples of jatobá was verified by the identification of the main compounds and multivariate analysis and contamination by microbial presence analysis. The acute toxicity of the authentic jatobá sap was also evaluated. The metabolites composition and multivariate analysis revealed that none of the commercial samples were authentic. In the microbiological contamination analysis, five of the six commercial samples showed positive cultures within the range of 1,700-100,000 CFU/mL and the authentic sap produced no signs of toxicity, and from a histological point of view, there was the maintenance of tissue integrity. In brief, the commercial samples were deemed inappropriate for consumption and represent a danger to the population.

SYNTHESIS AND BIOLOGICAL EVALUATION OF BIARYL ANALOGS OF ANTITUBULIN COMPOUNDS.

This paper reports the synthesis of methanones and esters bearing different substitution patterns as spacer groups between aromatic rings. This series of compounds can be considered phenstatin analogs. Two of the newly synthesized compounds, 5a and 5c, strongly inhibited tubulin polymerization and the binding of [(3)H] colchicine to tubulin, suggesting that, akin to phenstatin and combretastatin A-4, they can bind to tubulin at the colchicine site.