Epipelagic siphonophore assemblages associated with water masses along a transect between Chile and Easter Island (eastern South Pacific Ocean)

We analyze for the first time the spatial distribution of siphonophoresin relation to water masses along a 3750-km oceanic transectbetween the Chilean coast and the Easter Island (27° S),a sector scarcely known of eastern South Pacific Ocean. Thirty-onesiphonophore species were identified; Sulculeolaria turgidaand Vogtia glabra were recorded for the first time in this sector.The most abundant species were Muggiaea atlantica (29.2%), Eudoxoidesspiralis (24.5%) and Lensia subtilis (13.1%). Two differentsiphonophore assemblages east and west of 76 W, associated respectivelywith Subantarctic Water and Subtropical Water masses, can beused as water mass indicators. The former included the threemost abundant species, whereas the latter showed greater speciesrichness. This study provides basic knowledge on spatial distributionof siphonophores, which is important to develop future researchfocused on understanding the ecological role and biologicalprocesses driven by planktonic organisms in the southeasternPacific Ocean.     

New circuits for old memories: the role of the neocortex in consolidation

Studies of learning and memory have provided a great deal of evidence implicating hippocampal mechanisms in the initial storage of facts and events. However, until recently, there were few hints as to how and where this information was permanently stored. A recent series of rodent molecular and cellular cognition studies provide compelling evidence for the involvement of specific neocortical regions in the storage of information initially processed in the hippocampus. Areas of the prefrontal cortex, including the anterior cingulate and prelimbic cortices, and the temporal cortex show robust increases in activity specifically following remote memory retrieval. Importantly, damage to or inactivation of these areas produces selective remote memory deficits. Additionally, transgenic studies provide glimpses into the molecular and cellular mechanisms underlying cortical memory consolidation. The studies reviewed here represent the first exciting steps toward the understanding of the molecular, cellular, and systems mechanisms of how the brain stores our oldest and perhaps most defining memories.     

Fraying around the edges: negative effects of the invasive Tradescantia zebrina Hort. ex Bosse (Commelinaceae) on tree regeneration in the Atlantic Forest under different competitive and environmental conditions

Aims Invasive plants modify the structure and functioning of natural environments and threat native plant communities. Invasive species are often favored by human interference such as the creation of artificial forest edges. Field removal experiments may clarify if invasive plants are detrimental to native plant regeneration and how this is related to other local factors. We assessed the joint effect of environment and competition with the invasiveTradescantia zebrinaon tree species recruitment in an Atlantic Forest fragment.     

Passive restoration in Araucaria Forest: useful ecological indicators in monitoring successional advancement in exotic tree plantation landscapes

Monitoring successional advancement is a complex field involving a constant search for applied ecological indicators which facilitate monitoring of secondary forests for both active and passive restoration. In this study, the authors investigate the successional advancement of floristics and tree structure within Araucaria Forest (AF) fragments under passive restoration in a context where exotic tree plantations (mainly Pinus L. genus) dominate the landscape. The ecological indicators used were floristic dissimilarity (β‐diversity inferences), indicator species, ecological groups of species, basal area, and species abundance distribution (SAD) models (α‐diversity inferences). A total of 182 tree species belonging to 91 genera and 43 botanical families were identified. A high β diversity was verified for which each site has indicator species (for the locations CD—Dicksonia sellowiana; CO—Cryptocarya aschersoniana; and PG—Pinus taeda), where pioneer species contributed to much of the abundance. Different SAD models are useful for describing passive restoration sites in exotic tree plantation landscapes, namely Lognormal, Mandelbrot, and Zipf. SAD models together with basal area, taxonomic group (e.g. Myrtaceae assemblage), and tree abundance in ecological groups are strategic ecological indicators for monitoring successional advancement in AF.     

A reusable amperometric biosensor based on a novel silver-epoxy electrode for immunoglobulin detection

A renewable immunosensor consisting of an `epoxygraphite' biocomposite containing silver and tetracyanoquinodimethane (TCNQ) is described. These compounds enhance conductivity allowing the use of a smaller potential (0.28 v) which, in turn, enhances selectivity. This sensor, which may be renewed by simple polishing of its surface, was employed to detect human IgG using peroxidase-coupled anti-human IgG.     

Modulation of prion protein oligomerization, aggregation, and beta-sheet conversion by 4,4'-dianilino-1,1'-binaphthyl-5,5'-sulfonate (bis-ANS)

The prion protein (PrP) is the major agent implicated in the diseases known as transmissible spongiform encephalopathies. The onset of transmissible spongiform encephalopathy is related to a change in conformation of the PrP(C), which loses most of its alpha-helical content, becoming a beta-sheet-rich protein, known as PrP(Sc). Here we have used two Syrian hamster prion domains (PrP 109-141 and PrP 109-149) and the murine recombinant PrP (rPrP 23-231) to investigate the effects of anilino-naphtalene compounds on prion oligomerization and aggregation. Aggregation in the presence of bis-ANS (4,4'-dianilino-1,1'-binaphthyl-5,5'-sulfonate), ANS (1-anilinonaphthalene-8-sulfonate), and AmNS (1-amino-5-naphtalenesulfonate) was monitored. Bis-ANS was the most effective inhibitor of prion peptide aggregation. Bis-ANS binds strongly to rPrP 23-231 leading to a substantial increase in beta-sheet content and to limited oligomerization. More strikingly, the binding of bis-ANS to full-length rPrP is diminished by the addition of nanomolar concentrations of oligonucleotides, demonstrating that they compete for the same binding site. Thus, bis-ANS displays properties similar to those of nucleic acids, causing oligomerization and conversion to beta-sheet (Cordeiro, Y., Machado, F., Juliano, L., Juliano, M. A., Brentani, R. R., Foguel, D., and Silva, J. L. (2001) J. Biol. Chem. 276, 49400-49409). This dual effect of bis-ANS on prion protein makes this compound highly important to sequester crucial conformations of the protein, which may be useful to the understanding of the disease and to serve as a lead for the development of new therapeutic strategies.     

Comparative internal structure of dorsal lips and radiolar appendages in sabellidae (Polychaeta) and phylogenetic implications

Fan worms (Sabellidae) possess paired modified prostomial structures at the base of the radiolar crown, dorso‐lateral to the mouth, called dorsal lips. The dorsal lips are involved in the sorting of particles collected by the radiolar crown. The range of variation in the morphology of dorsal lips is extensive, and probably this is not only due to adaptations to different environments and feeding preferences but also due to phylogenetic constraints. In this study, we describe and compare the morphology of dorsal lips in a range of sabellid taxa based on histological cross‐sections of these structures, and compare our data and terminology with those of previous studies. Dorsal lips are maintained erect in most taxa by a modified radiole fused to them known as dorsal radiolar appendage. We suggest that dorsal radiolar appendages with an internal supporting axis (cellular or acellular) and probably also the ventral lips are synapomorphies of the family. J. Morphol., 2011. © 2010 Wiley‐Liss, Inc.     

Trypanosoma cruzi: Insights into naphthoquinone effects on growth and proteinase activity

In this study we compared the effects of naphthoquinones (α-lapachone, β-lapachone, nor-β-lapachone and Epoxy-α-lap) on growth of Trypanosoma cruzi epimastigotes forms, and on viability of VERO cells. In addition we also experimentally analyzed the most active compounds inhibitory profile against T. cruzi serine- and cysteine-proteinases activity and theoretically evaluated them against cruzain, the major T. cruzi cysteine proteinase by using a molecular docking approach. Our results confirmed β-lapachone and Epoxy-α-lap with a high trypanocidal activity in contrast to α-lapachone and nor-β-lapachone whereas Epoxy-α-lap presented the safest toxicity profile against VERO cells. Interestingly the evaluation of the active compounds effects against T. cruzi cysteine- and serine-proteinases activities revealed different targets for these molecules. β-Lapachone is able to inhibit the cysteine-proteinase activity of T. cruzi proteic whole extract and of cruzain, similar to E-64, a classical cysteine-proteinase inhibitor. Differently, Epoxy-α-lap inhibited the T. cruzi serine-proteinase activity, similar to PMSF, a classical serine-proteinase inhibitor. In agreement to these biological profiles in the enzymatic assays, our theoretical analysis showed that E-64 and β-lapachone interact with the cruzain specific S2 pocket and active site whereas Epoxy-α-lap showed no important interactions. Overall, our results infer that β-lapachone and Epoxy-α-lap compounds may inhibit T. cruzi epimastigotes growth by affecting T. cruzi different proteinases. Thus the present data shows the potential of these compounds as prototype of protease inhibitors on drug design studies for developing new antichagasic compounds.