Search

The intraspecies and interspecies Comparative Genomic Hybridization (CGH) between the closely related Cebidae species, capuchin monkeys (Cebus capucinus, Sapajus apella), and the tamarins (Saguinus mystax, Leontocebus fuscicollis) was performed to analyze their genomes. In particular, this approach determines balanced and unbalanced repetitive DNA sequence distribution and reveals dynamics during evolution. Capuchin monkeys are considered the most ancestral group with conserved syntenies compared to the hypothetical ancestral New World monkeys’ karyotype. Also, more derived karyotypes of phylogenetically distant species from the Saguinus and Leontocebus genera are analyzed here. The distribution of repetitive sequences has been traditionally studied through classical staining methods of cytogenetics. It has been hypothesized that repeats are species-specific and their conservation across closely related species are also common; their role in the genome has been extensively studied even though its role in speciation is not well studied and understood. The CGH shows bright signals with balanced and imbalanced DNA involving different genome regions: such as predominantly repetitive DNA at centromeric positions, and interstitial distribution with extended blocks. Cross-species CGH demonstrated the origin of some heterochromatic regions and identified apomorphic heterochromatin expansion events. The uncovered distribution of repetitive sequences is analyzed from an evolutionary perspective to elucidate the genomic dynamics of the repetitive sequences at the level of chromosomal organization.

The cell-free aqueous extract from the coelomic fluid of Holothuria tubulosa was prepared and examined for its glucose-lowering effect on HepG2 cells in vitro. In particular, employing a combination of cytochemical, flow cytometric, PCR, and protein blot techniques, we evaluated its role on glucose internalization and storage and on the upregulation and surface translocation of the two glucose transporters GLUT-2 and -4. The changes in expression, synthesis, and/or activation of the GLUT2-related transcription factor hepatocyte nuclear factor-1 alpha (HNF1α) and the GLUT-4-translocation regulatory factors insulin receptor substrate-1 (IRS-1) and AKT were also studied. Our results showed the improved glucose response by HepG2 cells, leading to an evident increase in glucose consumption/uptake and glycogen storage upon exposure. Moreover, the extract induced molecular reprogramming involving the upregulation of (i) IRS1 gene expression, (ii) the transcription and translation levels of HNF1α, AKT, and GLUT-4, (iii) the phosphorylation level of AKT, (iv) the synthesis of GLUT-2 protein, and (v) the translocation of GLUT-2 and -4 transporters onto the plasma membrane. Cumulatively, our results suggest that the coelomic fluid extract from H. tubulosa can be taken into consideration for the development of novel treatment agents against diabetes mellitus.

Aqueous extracts from Posidonia oceanica’s green and brown (beached) leaves and rhizomes were prepared, submitted to phenolic compound and proteomic analysis, and examined for their potential cytotoxic effect on HepG2 liver cancer cells in culture. The chosen endpoints related to survival and death were cell viability and locomotory behavior, cell-cycle analysis, apoptosis and autophagy, mitochondrial membrane polarization, and cell redox state. Here, we show that 24 h exposure to both green-leaf- and rhizome-derived extracts decreased tumor cell number in a dose–response manner, with a mean half maximal inhibitory concentration (IC50) estimated at 83 and 11.5 μg of dry extract/mL, respectively. Exposure to the IC50 of the extracts appeared to inhibit cell motility and long-term cell replicating capacity, with a more pronounced effect exerted by the rhizome-derived preparation. The underlying death-promoting mechanisms identified involved the down-regulation of autophagy, the onset of apoptosis, the decrease in the generation of reactive oxygen species, and the dissipation of mitochondrial transmembrane potential, although, at the molecular level, the two extracts appeared to elicit partially differentiating effects, conceivably due to their diverse composition. In conclusion, P. oceanica extracts merit further investigation to develop novel promising prevention and/or treatment agents, as well as beneficial supplements for the formulation of functional foods and food-packaging material with antioxidant and anticancer properties.