Geographic genetic structure of Iberian columbines (gen. <Emphasis Type="Italic">Aquilegia</Emphasis>)

Southern European columbines (genus Aquilegia) are involved in active processes of diversification, and the Iberian Peninsula offers a privileged observatory to witness the process. Studies on Iberian columbines have provided significant advances on species diversification, but we still lack a complete perspective of the genetic diversification in the Iberian scenario. This work explores how genetic diversity of the genus Aquilegia is geographically structured across the Iberian Peninsula. We used Bayesian clustering methods, principal coordinates analyses, and NJ phenograms to assess the genetic relationships among 285 individuals from 62 locations and detect the main lineages. Genetic diversity of Iberian columbines consists of five geographically structured lineages, corresponding to different Iberian taxa. Differentiation among lineages shows particularly complex admixture patterns at Northeast and highly homogeneous toward Northwest and Southeast. This geographic genetic structure suggests the existence of incomplete lineage sorting and interspecific hybridization as could be expected in recent processes of diversification under the influence of quaternary postglacial migrations. This scenario is consistent with what is proposed by the most recent studies on European and Iberian columbines, which point to geographic isolation and divergent selection by habitat specialization as the main diversification drivers of the Iberian Aquilegia complex.     

Kinetics of carbendazim degradation in a horizontal tubular biofilm reactor

Bioprocess and Biosystems Engineering - The fungicide carbendazim is an ecotoxic agent affecting aquatic biota. Due to its suspected hormone-disrupting effects, it is considered a “priority...     

Plasmid pVAX1-NH36 purification by membrane and bead perfusion chromatography

Bioprocess and Biosystems Engineering - The demand for plasmid DNA (pDNA) has increased in response to the rapid advances in vaccines applications to prevent and treat infectious diseases caused by...     

Isotopically labeled expression in E. coli, purification, and refolding of the full ectodomain of the influenza virus membrane fusion protein

This paper describes methods to produce an isotopically labeled 23 kDa viral membrane protein with purified yield of 20 mg/L of Escherichia coli shake flask culture. This yield is sufficient for NMR structural studies and the protein production methods are simple, straightforward, and rapid and likely applicable to other recombinant membrane proteins expressed in E. coli. The target FHA2 protein is the full ectodomain construct of the influenza virus hemagglutinin protein which catalyzes fusion between the viral and the cellular endosomal membranes during infection. The high yield of FHA2 was achieved by: (1) initial growth in rich medium to A₆₀₀  8 followed by a switch to minimal medium and induction of protein expression; and (2) obtaining protein both from purification of the detergent-soluble lysate and from solubilization, purification, and refolding of inclusion bodies. The high cell density was achieved after optimization of pH, oxygenation, and carbon source and concentration, and the refolding protocol was optimized using circular dichroism spectroscopy. For a single residue of membrane-associated FHA2 that was obtained from purification and refolding of inclusion bodies, native conformation was verified by the ¹³CO chemical shifts measured using solid-state nuclear magnetic resonance spectroscopy.     

Phylogeography and population genetics of the Amethyst-throated Hummingbird (Lampornis amethystinus)

We analyzed mitochondrial DNA sequence variation across 69 Amethyst-throated Hummingbirds (Lampornis amethystinus), comparing with samples of related taxa. Although this group shows discrete phenotypic variation in throat color among populations in Oaxaca and Guerrero (Mexico), the only phylogeographic structure observed was between phenotypically similar populations north and south of the Isthmus of Tehuantepec. As such, it appears that throat color variation is of recent origin and likely based only on minor genetic differences.     

A multi-locus phylogeny for Phytophthora utilizing markers derived from complete genome sequences.

Phytophthora species are devastating plant pathogens in both agricultural and natural environments. Due to their significant economic and environmental impact, there has been increasing interest in Phytophthora genetics and genomics, culminating in the recent release of three complete genome sequences (P. ramorum, P. sojae, and P. infestans). In this study, genome and other large sequence databases were used to identify over 225 potential genetic markers for phylogenetic analyses. Here, we present a genus-wide phylogeny for 82 Phytophthora species using seven of the most informative loci (approximately 8700 nucleotide sites). Our results support the division of the genus into 10 well-supported clades. The relationships among these clades were rigorously evaluated using a number of phylogenetic methods. This is the most comprehensive study of Phytophthora relationships to date, and many newly discovered species have been included. A more resolved phylogeny of Phytophthora species will allow for better interpretations of the overall evolutionary history of the genus.     

SIRT3 interacts with the daf-16 homolog FOXO3a in the mitochondria, as well as increases FOXO3a dependent gene expression

Cellular longevity is a complex process relevant to age-related diseases including but not limited to chronic illness such as diabetes and metabolic syndromes. Two gene families have been shown to play a role in the genetic regulation of longevity; the Sirtuin and FOXO families. It is also established that nuclear Sirtuins interact with and under specific cellular conditions regulate the activity of FOXO gene family proteins. Thus, we hypothesize that a mitochondrial Sirtuin (SIRT3) might also interact with and regulate the activity of the FOXO proteins. To address this we used HCT116 cells overexpressing either wild-type or a catalytically inactive dominant negative SIRT3. For the first time we establish that FOXO3a is also a mitochondrial protein and forms a physical interaction with SIRT3 in mitochondria. Overexpression of a wild-type SIRT3 gene increase FOXO3a DNA-binding activity as well as FOXO3a dependent gene expression. Biochemical analysis of HCT116 cells over expressing the deacetylation mutant, as compared to wild-type SIRT3 gene, demonstrated an overall oxidized intracellular environment, as monitored by increase in intracellular superoxide and oxidized glutathione levels. As such, we propose that SIRT3 and FOXO3a comprise a potential mitochondrial signaling cascade response pathway.     

Proteomics: advances in biomarker discovery

The challenges encountered by proteomic researchers seeking diagnostic, prognostic and mechanistic markers were the subject of the 1-day meeting, Proteomics: Advances in Biomarker Discovery hosted by EuroSciCon. The speakers had a broad range of clinical and basic science interests, and presented data using a number of proteomic platforms to search for discriminant biomarkers of disease in easily accessible bodily fluids including serum and urine. Several potential pitfalls for proteomic researchers were mentioned and the potential of collaborative networks between research institutions to increase the size and power of clinical studies was discussed. Overall, the meeting highlighted the exciting opportunities that proteomic techniques offer for discovering not only diagnostic but also prognostic and mechanistic markers of a number of clinically important diseases.