A third variant of glucose phosphate isomerase in pigs

A new variant of glucose phosphate isomerase (GPI), also known as phosphohexose isomerase (PHI), was detected in a primitive pig population.     

Functional and Phylogenetic Relatedness in Temporary Wetland Invertebrates: Current Macroecological Patterns and Implications for Future Climatic Change Scenarios

In freshwater ecosystems, species compositions are known to be determined hierarchically by large to small‑scale environmental factors, based on the biological traits of the organisms. However, in ephemeral habitats this heuristic framework remains largely untested. Although temporary wetland faunas are constrained by a local filter (i.e., desiccation), we propose its magnitude may still depend on large-scale climate characteristics. If this is true, climate should be related to the degree of functional and taxonomic relatedness of invertebrate communities inhabiting seasonal wetlands. We tested this hypothesis in two ways. First, based on 52 biological traits for invertebrates, we conducted a case study to explore functional trends among temperate seasonal wetlands differing in the harshness (i.e., dryness) of their dry season. After finding evidence of trait filtering, we addressed whether it could be generalized across a broader climatic scale. To this end, a meta-analysis (225 seasonal wetlands spread across broad climatic categories: Arid, Temperate, and Cold) allowed us to identify whether an equivalent climate-dependent pattern of trait richness was consistent between the Nearctic and the Western Palearctic. Functional overlap of invertebrates increased from mild (i.e., Temperate) to harsher climates (i.e., Arid and Cold), and phylogenetic clustering (using taxonomy as a surrogate) was highest in Arid and lowest in Temperate wetlands. We show that, (i) as has been described in streams, higher relatedness than would be expected by chance is generally observed in seasonal wetland invertebrate communities; and (ii) this relatedness is not constant but climate-dependent, with the climate under which a given seasonal wetland is located determining the functional overlap and the phylogenetic clustering of the community. Finally, using a space-for-time substitution approach we suggest our results may anticipate how the invertebrate biodiversity embedded in these vulnerable and often overlooked ecosystems will be affected by long-term climate change.     

The variability of the hepatitis B virus genome: statistical analysis and biological implications

A statistical analysis of the nucleotide sequence variability in 14 published hepatitis B virus (HBV) genomes was carried out using parametric and nonparametric methods. A parametric statistical model revealed that the different regions of the genome differed significantly in their variability. The conclusion was supported by a nonparametric kernel-density model of the HBV genome. Genes S, C, and P, region X, the precore region, and the pre-S2/pre-S1 regions were ranked in order of increasing variability. In many instances, conserved regions of the genome identified with sequences of known function in HBV biology. However, other characterized regions (such as pre-S) showed much variability despite the involvement of their encoded peptides in specific functions. Point mutations that may result in the formation of stop codons and amino acid changes may affect the clinical picture of HBV infection and may be reflected in atypical serological patterns.      

Spatial and temporal patterns of pioneer macrofauna in recently created ponds: taxonomic and functional approaches

The present study was carried out in Faxinal Reservoir, a warm monomictic, meso-eutrophic reservoir in subtropical southern Brazil, with a long-standing, well-stratified condition, low epilimnetic nutrient concentrations, and a relatively clear epilimnion. In this study, we analyzed the dynamics of the phytoplankton functional groups, recognizing their driving forces in Faxinal Reservoir. Samples were taken at monthly intervals from January 2004 to January 2005 in surface waters. According to the reservoir’s mixing regime, three periods were identified during the study: stratification 1 (January–May 2004); mixing period (June–August 2004); and stratification 2 (September 2004–January 2005). The nutrient dynamics were driven by the mixing regime. The H1, F, and C phytoplankton functional groups were the most important in biomass, mainly represented by the N-fixing cyanobacterium Anabaena crassa, the colonial green alga with thick mucilaginous sheaths Nephrocytium sp., and the diatom Asterionella formosa, respectively. Tendencies pointed out by redundancy analysis (RDA) indicated that the mixing regime was the main determining factor of the seasonal dynamics of the phytoplankton community. The dominant functional groups showed a close relationship with the relative water-column stability (RWCS), and also, as a consequence of the mixing regime, with nutrient availability. The study also revealed the important role of physical processes in the seasonal gradient, in selecting for phytoplankton functional groups and, consequently, in the assessment of ecological status. Q index (assemblage index) of water quality based on functional groups revealed ecological status varying from very poor to tolerable in the stratification 1 period and from tolerable to medium in the mixing and stratification 2 periods. Handling editor: Judit Padisak     

Stress‐induced vesicular assemblies of dual leucine zipper kinase are signaling hubs involved in kinase activation and neurodegeneration

Mitogen‐activated protein kinases (MAPKs) drive key signaling cascades during neuronal survival and degeneration. The localization of kinases to specific subcellular compartments is a critical mechanism to locally control signaling activity and specificity upon stimulation. However, how MAPK signaling components tightly control their localization remains largely unknown. Here, we systematically analyzed the phosphorylation and membrane localization of all MAPKs expressed in dorsal root ganglia (DRG) neurons, under control and stress conditions. We found that MAP3K12/dual leucine zipper kinase (DLK) becomes phosphorylated and palmitoylated, and it is recruited to sphingomyelin‐rich vesicles upon stress. Stress‐induced DLK vesicle recruitment is essential for kinase activation; blocking DLK‐membrane interaction inhibits downstream signaling, while DLK recruitment to ectopic subcellular structures is sufficient to induce kinase activation. We show that the localization of DLK to newly formed vesicles is essential for local signaling. Inhibition of membrane internalization blocks DLK activation and protects against neurodegeneration in DRG neurons. These data establish vesicular assemblies as dynamically regulated platforms for DLK signaling during neuronal stress responses.     

Characterization and location of post-translational modifications on chromogranin B from bovine adrenal medullary chromaffin granules

Bovine chromoganin B (CGB)/secretogranin I, an acidic protein with a sequence of 626 residues and an isoelectric point of 5.2 is a major member of the chromogranin/secretogranin (CG/Sg) family. The difference between the theoretical molecular mass (76 kDa) and the value estimated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis results from post-translational modifications (glycosylation, phosphorylation and sulfation) and from the abundance of acidic residues (D 4.6%, and E 16.5%). Although the sequence of CGB is known, the structural analyses of the post-translational modifications have so far not been carried out. In the present study, using a combination of proteomic techniques including two-dimensional gel electrophoresis, Western blot, high-performance liquid chromatography purification, enzymatic digestion, sequencing, carbohydrate analysis, matrix-assisted laser desorption/ionization-time of flight and liquid chromatography mass spectrometry analysis, we have located 18 post-translational modifications on bovine CGB, isolated from adrenal medulla chromaffin granules. Furthermore, we have identified at the molecular level the presence of a mutation M/V on position 577 of natural CGB. All together these data reflect the complex structure of this protein marker of the neuroendocrine system.