Plumage coloration and personality in early life: sexual differences in signalling

Several studies have shown that melanin‐based traits play a crucial role in social contexts as they are associated with dominance, personality and social behaviour. However, most of these studies have focused on adults, and the role of these traits in juveniles has rarely been explored. Here, we explore the association between two melanin‐based traits and nestling personality in Common Kestrels Falco tinnunculus. Our results show that female nestlings with blacker plumages displayed bolder personalities, providing evidence of sex‐dependent phenotypic integration of these two traits in males and females. We consider that this differential integration may arise from different selection pressures acting on males and females on plumage coloration during adulthood and that nestling coloration can act as a status signal within the juvenile age‐class.     

GROmaρs: A GROMACS-Based Toolset to Analyze Density Maps Derived from Molecular Dynamics Simulations

We introduce a computational toolset, named GROmaρs, to obtain and compare time-averaged density maps from molecular dynamics simulations. GROmaρs efficiently computes density maps by fast multi-Gaussian spreading of atomic densities onto a three-dimensional grid. It complements existing map-based tools by enabling spatial inspection of atomic average localization during the simulations. Most importantly, it allows the comparison between computed and reference maps (e.g., experimental) through calculation of difference maps and local and time-resolved global correlation. These comparison operations proved useful to quantitatively contrast perturbed and control simulation data sets and to examine how much biomolecular systems resemble both synthetic and experimental density maps. This was especially advantageous for multimolecule systems in which standard comparisons like RMSDs are difficult to compute. In addition, GROmaρs incorporates absolute and relative spatial free-energy estimates to provide an energetic picture of atomistic localization. This is an open-source GROMACS-based toolset, thus allowing for static or dynamic selection of atoms or even coarse-grained beads for the density calculation. Furthermore, masking of regions was implemented to speed up calculations and to facilitate the comparison with experimental maps. Beyond map comparison, GROmaρs provides a straightforward method to detect solvent cavities and average charge distribution in biomolecular systems. We employed all these functionalities to inspect the localization of lipid and water molecules in aquaporin systems, the binding of cholesterol to the G protein coupled chemokine receptor type 4, and the identification of permeation pathways through the dermicidin antimicrobial channel. Based on these examples, we anticipate a high applicability of GROmaρs for the analysis of molecular dynamics simulations and their comparison with experimentally determined densities.     

Coupling physiological analysis with proteomic profile to understand the photosynthetic responses of young Euterpe oleracea palms to drought

Photosynthesis Research - This study examined whether drought sensitivity in açaí (Euterpe oleracea Mart.) is associated with reductions in photosynthesis and increasing oxidative stress...     

Role of two conserved cytoplasmic threonine residues (T410 and T412) in CD5 signaling

CD5 is a transmembrane coreceptor that modulates activation and differentiation signals mediated by the Ag-specific receptor present on both T and B1a lymphocytes. CD5 lacks intrinsic catalytic activity, and its immunomodulatory properties result from intracellular interactions mediated by the CD5 cytoplasmic tail. The nature of these interactions is currently a matter of investigation. Here, we present a selective mutagenesis analysis of two conserved threonine residues (T410 and T412) located at the membrane-proximal cytoplasmic region of CD5. These residues are contained within consensus phosphorylation motifs for protein kinase C and are shown here to be critical for in vivo protein kinase C-mediated phosphorylation of CD5. Functional studies revealed that the integrity of T410 and T412 is also critical for CD5-mediated phosphatidylcholine-specific phospholipase C (PC-PLC) activation and phorbol ester-mediated inhibition of Ab-induced internalization of CD5. These results strongly argue in favor of a role for T410 and T412 in the signaling mediated by CD5.     

Thymulin and the neuroendocrine system

Thymulin is a thymic hormone exclusively produced by the thymic epithelial cells. It consists of a nonapeptide component coupled to the ion zinc, which confers biological activity to this molecule. After its discovery in the early 1970, thymulin was characterized as a thymic hormone involved in several aspects of intra- and extrathymic T-cell differentiation. Subsequently, it was demonstrated that thymulin production and secretion is strongly influenced by the neuroendocrine system. Conversely, an emerging core of information points to thymulin as a hypophysotropic peptide. Here we review the evidence supporting the hypothesis that thymulin is an important player in the hypophyso-thymic axis.     

Crystal structure of glycogen synthase: homologous enzymes catalyze glycogen synthesis and degradation

Glycogen and starch are the major readily accessible energy storage compounds in nearly all living organisms. Glycogen is a very large branched glucose homopolymer containing about 90% alpha-1,4-glucosidic linkages and 10% alpha-1,6 linkages. Its synthesis and degradation constitute central pathways in the metabolism of living cells regulating a global carbon/energy buffer compartment. Glycogen biosynthesis involves the action of several enzymes among which glycogen synthase catalyzes the synthesis of the alpha-1,4-glucose backbone. We now report the first crystal structure of glycogen synthase in the presence and absence of adenosine diphosphate. The overall fold and the active site architecture of the protein are remarkably similar to those of glycogen phosphorylase, indicating a common catalytic mechanism and comparable substrate-binding properties. In contrast to glycogen phosphorylase, glycogen synthase has a much wider catalytic cleft, which is predicted to undergo an important interdomain 'closure' movement during the catalytic cycle. The structures also provide useful hints to shed light on the allosteric regulation mechanisms of yeast/mammalian glycogen synthases.     

<Emphasis Type="Italic">Rhodospirillum rubrum</Emphasis> has a family I pyrophosphatase: purification,cloning, and sequencing

The cytoplasmic pyrophosphatase of the photosynthetic bacterium Rhodospirillum rubrum was purified to electrophoretic homogeneity. The enzyme is a homohexamer of 20-kDa monomers. The gene was cloned and sequenced. Alignment of the deduced 179-amino-acid protein with known bacterial pyrophosphatases revealed conservation of all residues in the active site. Attempts to obtain an insertion mutant of the cytoplasmic pyrophosphatase gene did not yield any cell completely devoid of cytoplasmic pyrophosphatase activity. The mutants obtained showed 50% of the enzymatic activity and grew in twice the generation time of wild-type cells. This suggests that the membrane-bound pyrophosphatase of Rsp. rubrum is not sufficient for a normal growth rate, whereas the cytoplasmic enzyme is essential for growth. The characteristics of the gene and the encoded protein fit those of prokaryotic family I pyrophosphatases.     

The 1.15A crystal structure of the Staphylococcus aureus methionyl-aminopeptidase and complexes with triazole based inhibitors

Methionyl aminopeptidases (MetAPs) represent a unique class of protease that are responsible for removing the N-terminal methionine residue from proteins and peptides. There are two major classes of MetAPs (type I and type II) described and each class can be subdivided into two subclasses. Eukaryotes contain both the type I and type II MetAPs, whereas prokaryotes possess only the type I enzyme. Due to the physiological importance of these enzymes there is considerable interest in inhibitors to be used as antiangiogenic and antimicrobial agents. Here, we describe the 1.15A crystal structure of the Staphylococcus aureus MetAP-I as an apo-enzyme and its complexes with various 1,2,4-triazole-based derivatives at high-resolution. The protein has a typical "pita-bread" fold as observed for the other MetAP structures. The inhibitors bind in the active site with the N1 and N2 atoms of the triazole moiety complexing two divalent ions. The 1,2,4-triazols represent a novel class of potent non-peptidic inhibitors for the MetAP-Is.