Maternal effects and urbanization: Variation of yolk androgens and immunoglobulin in city and forest blackbirds

Wildlife inhabiting urban environments exhibit drastic changes in morphology, physiology, and behavior. It has often been argued that these phenotypic responses could be the result of micro‐evolutionary changes following the urbanization process. However, other mechanisms such as phenotypic plasticity, maternal effects, and developmental plasticity could be involved as well. To address maternal effects as potential mechanisms, we compared maternal hormone and antibody concentrations in eggs between city and forest populations of European blackbirds (Turdus merula), a widely distributed species for which previous research demonstrated differences in behavioral and physiological traits. We measured egg and yolk mass, yolk concentrations of androgens (androstenedione [A₄], testosterone [T], 5α‐dihydrotestosterone [5α‐DHT], and immunoglobulins [IgY]) and related them to population, clutch size, laying order, embryo sex, and progress of breeding season. We show (a) earlier onset of laying in the city than forest population, but similar egg and clutch size; (b) higher overall yolk androgen concentrations in the forest than the city population (sex‐dependent for T); (c) greater among‐female variation of yolk T and 5α‐DHT concentrations in the forest than city population, but similar within‐clutch variation; (d) similar IgY concentrations with a seasonal decline in both populations; and (e) population‐specific positive (city) or negative (forest) association of yolk A₄ and T with IgY concentrations. Our results are consistent with the hypotheses that hormone‐mediated maternal effects contribute to differences in behavioral and physiological traits between city and forest individuals and that yolk androgen and immunoglobulin levels can exhibit population‐specific relationships rather than trade‐off against each other.     

Peptidomic analysis of skin secretions demonstrates that the allopatric populations of Xenopus muelleri (Pipidae) are not conspecific

Mueller's clawed frog Xenopus muelleri (Peters 1844) occupies two non-contiguous ranges in east and west Africa. The phylogenetic relationship between the two populations is unclear and it has been proposed that the western population represents a separate species. Peptidomic analysis of norepinephrine-stimulated skin secretions from X. muelleri from the eastern range resulted in the identification of five antimicrobial peptides structurally related to the magainins (magainin-M1 and -M2), xenopsin-precursor fragments (XPF-M1) and caerulein-precursor fragments (CPF-M1 and -M2) previously found in skin secretions of other Xenopus species. A cyclic peptide (WCPPMIPLCSRF.NH₂) containing the RFamide motif was also isolated that shows limited structural similarity to the tigerinins, previously identified only in frogs of the Dicroglossidae family. The components identified in skin secretions from X. muelleri from the western range comprised one magainin (magainin-MW1), one XPF peptide (XPF-MW1), two peptides glycine-leucine amide (PGLa-MW1 and -MW2), and three CPF peptides (CPF-MW1, -MW2 and -MW3). Comparison of the primary structures of these peptides suggest that western population of X. muelleri is more closely related to X. borealis than to X. muelleri consistent with its proposed designation as a separate species. The CPF peptides showed potent, broad-spectrum activity against reference strains of bacteria (MIC 3-25 μM), but were hemolytic against human erythrocytes.     

Identification by photoaffinity labeling of the extracellular N-terminal domain of PAC1 receptor as the major binding site for PACAP

Pituitary adenylate cyclase-activating polypeptide (PACAP) exerts many crucial biological functions through the interaction with its specific PAC1 receptor (PAC1-R), a class B G protein-coupled receptor (GPCR). To identify the binding sites of PACAP in the PAC1-R, three peptide derivatives containing a photoreactive p-benzoyl-phenylalanine (Bpa) residue were developed. These photosensitive PACAP analogs were fully biologically active and competent to displace radiolabeled Ac-PACAP27 from the PAC1-R. Subsequently, the ¹²⁵I-labeled photoprobes were used to anchor the PAC1-R expressed in Chinese hamster ovary cells. Photolabeling led to the formation of two protein complexes of 76 and 67 kDa, representing different glycosylated forms of the receptor. Proteinase and chemical cleavages of the peptide-receptor complexes revealed that ¹²⁵I[Bpa⁰, Nle¹⁷]PACAP27, ¹²⁵I[Bpa⁶, Nle¹⁷]PACAP27 and ¹²⁵I[Nle¹⁷, Bpa²²]PACAP27 covalently labeled the Ser⁹⁸ - Met¹¹¹ segment, the Ser¹²⁴ - Glu¹²⁵ dipeptide and the Ser¹⁴¹ - Met¹⁷² fragment, respectively. Taking into account the topology of the PAC1-R, these segments are mainly located within the extracellular N-terminal domain, indicating that this PAC1-R domain is the major binding site of PACAP27. The present study constitutes the first characterization of the binding domains of PACAP to its specific receptor and suggests heterogeneity within the binding mode of peptide ligands to class B GPCRs.     

The Late Neolithic settlement of Latsch, Vinschgau, northern Italy: subsistence of a settlement contemporary with the Alpine Iceman, and located in his valley of origin

Archaeobotanical and archaeozoological analyses conducted on Late Neolithic settlement layers at Latsch provide the first data on the subsistence strategy, diet and environmental conditions in the valley of origin of the Alpine Iceman. The results prove that during the Late Neolithic, the valley was occupied by an agro-pastoral society based on the cultivation of Hordeum vulgare (hulled barley), Triticum monococcum (einkorn), T. dicoccum (emmer) and Pisum sativum (pea), as well as on the rearing of Ovis vel Capra, Ovis orientalis f. aries (sheep), Capra aegagrus f. hircus (goat) and Bos primigenius f. taurus (cattle). The settlement was located on a river terrace of the valley floor close to a river and was surrounded by mixed pine and oak woods beside alluvial woodland.     

Spectrin-like repeats 11-15 of human dystrophin show adaptations to a lipidic environment

Dystrophin is essential to skeletal muscle function and confers resistance to the sarcolemma by interacting with cytoskeleton and membrane. In the present work, we characterized the behavior of dystrophin 11-15 (DYS R11-15), five spectrin-like repeats from the central domain of human dystrophin, with lipids. DYS R11-15 displays an amphiphilic character at the liquid/air interface while maintaining its secondary α-helical structure. The interaction of DYS R11-15 with small unilamellar vesicles (SUVs) depends on the lipid nature, which is not the case with large unilamellar vesicles (LUVs). In addition, switching from anionic SUVs to anionic LUVs suggests the lipid packing as a crucial factor for the interaction of protein and lipid. The monolayer model and the modulation of surface pressure aim to mimic the muscle at work (i.e. dynamic changes of muscle membrane during contraction and relaxation) (high and low surface pressure). Strikingly, the lateral pressure modifies the protein organization. Increasing the lateral pressure leads the proteins to be organized in a regular network. Nevertheless, a different protein conformation after its binding to monolayer is revealed by trypsin proteolysis. Label-free quantification by nano-LC/MS/MS allowed identification of the helices in repeats 12 and 13 involved in the interaction with anionic SUVs. These results, combined with our previous studies, indicate that DYS R11-15 constitutes the only part of dystrophin that interacts with anionic as well as zwitterionic lipids and adapts its interaction and organization depending on lipid packing and lipid nature. We provide strong experimental evidence for a physiological role of the central domain of dystrophin in sarcolemma scaffolding through modulation of lipid-protein interactions.     

Temporal variation of vitellogenin synthesis in Ectatomma tuberculatum (Formicidae: Ectatomminae) workers

Workers of the ant species Ectatomma tuberculatum (Ectatomminae) have active ovaries and lay eggs that are eaten by the queen and larvae (trophic eggs). Vitellogenins are the main proteins found in the eggs of insects and are a source of nutrients. The aim of this study was to characterize the period of vitellogenin production in workers of E. tuberculatum. The vitellogenin was identified from queen and worker eggs by SDS-PAGE. Anti-vitellogenin antibodies were obtained and used to detect this protein in the fat body and haemolymph of workers at different ages. Vitellogenin from E. tuberculatum consists of two polypeptides of 31 and 156 kDa. In the eggs of queens, the 156 kDa polypeptide is cleaved into two subunits of 36 and 123 kDa. The analysis of the haemolymph of workers showed that the secretion of vitellogenin varies with age. The secretion is initiated around the fifth day after emergence, with peak production from days 20 to 60, and stops around day 100. The variation in production is related to the different activities performed by the workers within the colony, suggesting that vitellogenin may have an important role in maintaining age polyethism.