Bacterial assemblages structure in intensive cultivations of the microalga Tetradesmus obliquus.

The present study shows the characterization of the bacterial communities associated with different systems during the cultivation of the microalga Tetradesmus obliquus. For that, sequential cultivation was performed in three different systems: (1) Photobioreactor bench-scale; (2) flat-panel photobioreactor; and (3) thin-layer cascade. Cultures were monitored daily for growth parameters and biomass samples were collected for characterization of bacterial communities using metagenomic. A total of 195,177 reads were produced, resulting in the identification of 72 OTUs. In the grouping of bacterial communities, 3 phyla, 6 classes, 28 families, and 35 taxa were found. The bacteria Brevundimonas and Porphyrobacter had a higher relative abundance compared with other taxa found. These taxa were present in all cultivation systems forming a possible core community. Bacterial communities associated with different cultivation systems of the microalga T. obliquus showed an increase in taxa richness and diversity in the super-intensive and intensive systems.

Anti-cancer Effects of Fucoxanthin on Human Glioblastoma Cell Line.

BACKGROUND/AIM: Glioblastomas (GBMs) are the most malignant primary brain tumor. New treatment strategies against the disease are urgently needed, as therapies are not completely efficient. In this study, we evaluated the antitumorigenic activity of the carotenoid fucoxanthin (Fx) on human GBM cells in vitro. MATERIALS AND METHODS: GBM1 cell viability and proliferation was assessed by MTT reduction, Ki67 and single cell cloning assays. GBM1 migration and invasion were analyzed by wound healing and Transwell assays. Apoptosis and necrosis were analyzed by flow cytometry, and the mitochondrial membrane potential (ΔΨm) by the selective fluorescent dye tetramethylrhodamine ethyl ester. Cell morphology was analyzed through scanning electron microscopy and transmission electron microscopy. Fx anti-angiogenic effect was assessed by the CAM ex ovo assay. RESULTS: Fx decreased cell viability in a concentration-dependent manner (40-100 µ M) in GBM1, A172 and C6 cell lines and was not cytotoxic to murine astrocytes. In addition, Fx inhibited the proliferation and clonogenic potential, and decreased migration and invasion of GBM1 cells. Furthermore, Fx induced apoptosis, loss of ΔΨm and ultrastructural alterations in GBM1. Fx-treated GBM1 cells-conditioned medium reduced the quail yolk membrane vascularity. CONCLUSION: Fx induces cytotoxicity, anti-proliferative, anti-invasive and anti-angiogenic effects on GBM1 cells.