Halophilic organisms inhabit hypersaline environments where the extreme ionic conditions and osmotic pressure have driven the evolution of molecular adaptation mechanisms. Understanding such mechanisms is limited by the common difficulties encountered in cultivating such organisms. Within the Euryarchaeota, for example, only the Halobacteria and the order Methanosarcinales include readily cultivable halophilic species. Furthermore, only the former have been extensively studied in terms of their component proteins. Here, in order to redress this imbalance, we investigate the halophilic adaptation of glycolytic enzymes from the ADP-dependent phosphofructokinase/glucokinase family (ADP-PFK/GK) derived from organisms of the order Methanosarcinales. Structural analysis of proteins from non-halophilic and halophilic Methanosarcinales shows an almost identical composition and distribution of amino acids on both the surface and within the core. However, these differ from those observed in Halobacteria or Eukarya. Proteins from Methanosarcinales display a remarkable increase in surface lysine content and have no reduction to the hydrophobic core, contrary to the features ubiquitously observed in Halobacteria and which are thought to be the main features responsible for their halophilic properties. Biochemical characterization of recombinant ADP-PFK/GK from M. evestigatum (halophilic) and M. mazei (non-halophilic) shows the activity of both these extant enzymes to be only moderately inhibited by salt. Nonetheless, its activity over time is notoriously stabilized by salt. Furthermore, glycine betaine has a protective effect against KCl inhibition and enhances the thermal stability of both enzymes. The resurrection of the last common ancestor of ADP-PFK/GK from Methanosarcinales shows that the ancestral enzyme displays an extremely high salt tolerance and thermal stability. Structure determination of the ancestral protein reveals unique traits such as an increase in the Lys and Glu content at the protein surface and yet no reduction to the volume of the hydrophobic core. Our results suggest that the halophilic character is an ancient trait in the evolution of this protein family and that proteins from Methanosarcinales have adapted to highly saline environments by a non-canonical strategy, different from that currently proposed for Halobacteria. These results open up new avenues for the search and development of novel salt tolerant biocatalysts.

Single-nucleotide polymorphisms (SNPs) are single genetic code variations considered one of the most common forms of nucleotide modifications. Such SNPs can be located in genes associated to immune response and, therefore, they may have direct implications over the phenotype of susceptibility to infections affecting the productive sector. In this study, a set of immune-related genes (cc motif chemokine 19 precursor [ccl19], integrin b2 (itb2, also named cd18), glutathione transferase omega-1 [gsto-1], heat shock 70 KDa protein [hsp70], major histocompatibility complex class I [mhc-I]) were analyzed to identify SNPs by data mining. These genes were chosen based on their previously reported expression on infectious pancreatic necrosis virus (IPNV)-infected Atlantic salmon phenotype. The available EST sequences for these genes were obtained from the Unigene database. Twenty-eight SNPs were found in the genes evaluated and identified most of them as transition base changes. The effect of the SNPs located on the 5'-untranslated region (UTR) or 3'-UTR upon transcription factor binding sites and alternative splicing regulatory motifs was assessed and ranked with a low-medium predicted FASTSNP score risk. Synonymous SNPs were found on itb2 (c.2275G > A), gsto-1 (c.558G > A), and hsp70 (c.1950C > T) with low FASTSNP predicted score risk. The difference in the relative synonymous codon usage (RSCU) value between the variant codons and the wild-type codon (DRSCU) showed one negative (hsp70 c.1950C > T) and two positive DRSCU values (itb2 c.2275G > A; gsto-1 c.558G > A), suggesting that these

Polybrominated diphenyl ethers (PBDEs) are a group of molecules with an ambiguous background in literature. PBDEs were first isolated from marine sponges of Dysidea species in 1981 and have been under continuous research to the present day. This article summarizes the two research aspects, (i) the marine compound chemistry research dealing with naturally produced PBDEs and (ii) the environmental toxicology research dealing with synthetically-produced brominated flame-retardant PBDEs. The different bioactivity patterns are set in relation to the structural similarities and dissimilarities between both groups. In addition, this article gives a first structure–activity relationship analysis comparing both groups of PBDEs. Moreover, we provide novel data of a promising anticancer therapeutic PBDE (i.e., 4,5,6-tribromo-2-(2′,4′-dibromophenoxy)phenol; termed P01F08). It has been known since 1995 that P01F08 exhibits anticancer activity, but the detailed mechanism remains poorly understood. Only recently, Mayer and colleagues identified a therapeutic window for P01F08, specifically targeting primary malignant cells in a low µM range. To elucidate the mechanistic pathway of cell death induction, we verified and compared its cytotoxicity and apoptosis induction capacity in Ramos and Jurkat lymphoma cells. Moreover, using Jurkat cells overexpressing antiapoptotic Bcl-2, we were able to show that P01F08 induces apoptosis mainly through the intrinsic mitochondrial pathway.

No abstract

No abstract

No abstract

No abstract

No abstract