Pollination And Breeding System Of Canna Paniculata (cannaceae) In A Montane Atlantic Rainforest: Asymmetric Dependence On A Hermit Hummingbird

We studied the pollination biology of Canna paniculata (Cannaceae), a plant species common in the Atlantic Rainforest of southeastern Brazil. The species presents specialized ornithophilous flowers, which in our study area are solely pollinated by the hermit hummingbird Phaethornis eurynome. Although C. paniculata is capable of bearing fruit after self-pollination, it requires pollinators for reproduction. We discuss the importance of hermit hummingbirds for the reproduction of specialized ornithophilous plants such as C. paniculata, including their asymmetric dependence on hermit hummingbirds - core pollinators in Neotropical forest ecosystems.291157160Cronk, Q., Ojeda, I., Bird-pollinated flowers in an evolutionary and molecular context (2008) Journal of Experimental Botany, 59, pp. 715-727Glinos, E., Cocucci, A.A., Pollination biology of Canna indica (Cannaceae) with particular reference to the functional morphology of the style (2011) Plant Systematics and Evolution, 291, pp. 49-58Justino, D.G., Maruyama, P.K., Oliveira, P.E., Floral resource availability and hummingbird territorial behaviour on a Neotropical savanna shrub (2012) Journal of Ornithology, 153, pp. 189-197Kay, K.M., Schemske, D.W., Pollinator assemblages and visitation rates for 11 species of Neotropical Costus (Costaceae) (2003) Biotropica, 35, pp. 198-207Maruyama, P.K., Oliveira, G.M., Ferreira, C., Dalsgaard, B., Oliveira, P.E., Pollination syndromes ignored: Importance of non-ornithophilous flowers to Neotropical savanna hummingbirds (2013) Naturwissenschaften, 100, pp. 1061-1068Maruyama, P.K., Vizentin-Bugoni, J., Oliveira, G.M., Oliveira, P.E., Dalsgaard, B., Morphological and spatio-temporal mismatches shape a Neotropical savanna plant-hummingbird network (2014) Biotropica, 46, pp. 740-747Matallana, G., Godinho, M.A.S., Guilherme, F.A.G., Belisario, M., Coser, T.S., Wendt, T., Breeding systems of Bromeliaceae species: Evolution of selfing in the context of sympatric occurrence (2010) Plant Systematics and Evolution, 289, pp. 57-67McGuire, J.A., Witt, C.C., Remsen, J.V., Jr., Molecular phylogenetics and the diversification of hummingbirds (2014) Current Biology, 24, pp. 910-916Prince, L.M., Phylogenetic relationships and species delimitation in Canna (Cannaceae) (2010) Diversity, phylogeny, and evolution in the monocotyledons, pp. 307-331. , Seberg O, Petersen G, Barfod AS, Davis J. (eds.) Aarhus, Aarhus University PressSakai, S., Kato, M., Inoue, T., Three pollination guilds and variation in floral characteristics of Bornean gingers (Zingiberaceae and Costaceae) (1999) American Journal of Botany, 86, pp. 646-658Sazima, I., Buzato, S., Sazima, M., The saw-billed hermit Ramphodon naevius and its flowers in southeastern Brazil (1995) Journal of Ornithology, 136, pp. 195-206Schmidt-Lebuhn, A.N., Kessler, M., Hensen, I., Hummingbirds as drivers of plant speciation? (2007) Trends in Plant Science, 12, pp. 329-331Stiles, F.G., Ecology, flowering phenology, and hummingbird pollination of some Costa Rican Heliconia species (1975) Ecology, 56, pp. 285-301Vizentin-Bugoni, J., Maruyama, P.K., Sazima, M., Processes entangling interactions in communities: Forbidden links are more important than abundance in a hummingbird-plant network (2014) Proceedings of the Royal Society B: Biological Sciences, 281Wolowski, M., Saad, C.F., Ashman, T.L., Freitas, L., Predominance of selfcompatibility in hummingbird-pollinated plants in the Neotropics (2013) Naturwissenschaften, 100, pp. 69-7

Determinants Of Bird Species Richness, Endemism, And Island Network Roles In Wallacea And The West Indies: Is Geography Sufficient Or Does Current And Historical Climate Matter?

Island biogeography has greatly contributed to our understanding of the processes determining species' distributions. Previous research has focused on the effects of island geography (i.e., island area, elevation, and isolation) and current climate as drivers of island species richness and endemism. Here, we evaluate the potential additional effects of historical climate on breeding land bird richness and endemism in Wallacea and the West Indies. Furthermore, on the basis of species distributions, we identify island biogeographical network roles and examine their association with geography, current and historical climate, and bird richness/endemism. We found that island geography, especially island area but also isolation and elevation, largely explained the variation in island species richness and endemism. Current and historical climate only added marginally to our understanding of the distribution of species on islands, and this was idiosyncratic to each archipelago. In the West Indies, endemic richness was slightly reduced on islands with historically unstable climates; weak support for the opposite was found in Wallacea. In both archipelagos, large islands with many endemics and situated far from other large islands had high importance for the linkage within modules, indicating that these islands potentially act as speciation pumps and source islands for surrounding smaller islands within the module and, thus, define the biogeographical modules. Large islands situated far from the mainland and/or with a high number of nonendemics acted as links between modules. Additionally, in Wallacea, but not in the West Indies, climatically unstable islands tended to interlink biogeographical modules. The weak and idiosyncratic effect of historical climate on island richness, endemism, and network roles indicates that historical climate had little effects on extinction-immigration dynamics. This is in contrast to the strong effect of historical climate observed on the mainland, possibly because surrounding oceans buffer against strong climate oscillations and because geography is a strong determinant of island richness, endemism and network roles. We evaluate the potential additional effects of historical climate on native breeding land bird species richness, endemism and island network roles in Wallacea and the West Indies. We find that island geography, especially island area but also isolation and elevation, largely explained the variation in island species richness and endemism, and that island network roles are tightly linked to geography and endemism. The weak and idiosyncratic effect of historical climate on island richness, endemism and network roles indicates that historical climate had little effects on extinction-immigration dynamics in Wallacea and the West Indies. This is in contrast to the strong effect of historical climate observed on the mainland, possibly because surrounding oceans buffer against strong climate oscillations and because geography is a strong determinant of island richness, endemism and network roles

Physical interaction between bacterial heat shock protein (Hsp) 90 and Hsp70 chaperones mediates their cooperative action to refold denatured proteins.

In eukaryotes, heat shock protein 90 (Hsp90) is an essential ATP-dependent molecular chaperone that associates with numerous client proteins. HtpG, a prokaryotic homolog of Hsp90, is essential for thermotolerance in cyanobacteria, and in vitro it suppresses the aggregation of denatured proteins efficiently. Understanding how the non-native client proteins bound to HtpG refold is of central importance to comprehend the essential role of HtpG under stress. Here, we demonstrate by yeast two-hybrid method, immunoprecipitation assays, and surface plasmon resonance techniques that HtpG physically interacts with DnaJ2 and DnaK2. DnaJ2, which belongs to the type II J-protein family, bound DnaK2 or HtpG with submicromolar affinity, and HtpG bound DnaK2 with micromolar affinity. Not only DnaJ2 but also HtpG enhanced the ATP hydrolysis by DnaK2. Although assisted by the DnaK2 chaperone system, HtpG enhanced native refolding of urea-denatured lactate dehydrogenase and heat-denatured glucose-6-phosphate dehydrogenase. HtpG did not substitute for DnaJ2 or GrpE in the DnaK2-assisted refolding of the denatured substrates. The heat-denatured malate dehydrogenase that did not refold by the assistance of the DnaK2 chaperone system alone was trapped by HtpG first and then transferred to DnaK2 where it refolded. Dissociation of substrates from HtpG was either ATP-dependent or -independent depending on the substrate, indicating the presence of two mechanisms of cooperative action between the HtpG and the DnaK2 chaperone system

Baryon flow at SIS energies

We calculate the baryon flow $$ in the energy range from .25 to $\le 2.5 AGeV$ in a relativistic transport model for $Ni+Ni$ and $Au+Au$ collisions employing various models for the baryon self energies. We find that to describe the flow data of the FOPI Collaboration the strength of the vector potential has to be reduced at high relative momentum or at high density such that the Schr\"odinger- equivalent potential at normal nuclear density decreases above 1 GeV relative kinetic energy and approaches zero above 2 GeV.Comment: 20 pages, LATEX, 7 PostScript figure

Baryon flow from SIS to AGS energies

We analyze the baryon sideward and elliptic flow from SIS (0.25 $\sim$ 2 A GeV) to AGS (2 $\sim 11.0A$GeV) energies for Au + Au collisions in the relativistic transport model RBUU that includes all baryon resonances up to a mass of 2 GeV as well as string degrees of freedom for the higher mass continuum. There are two factors which dominantly determine the baryon flow at these energies: the momentum dependence of the scalar and vector potentials and the resonance-string degrees of freedom. We fix the explicit momentum dependence of the nucleon-meson couplings within the NL3 parameter set by the nucleon optical potential up to 1 GeV of kinetic energy. When assuming the optical potential to vanish identically for $E_{kin} \geq 3.5$ GeV we simultaneously reproduce the sideward flow data of the FOPI, EOS, E895 and E877 collaborations, the elliptic flow data of the EOS, E895 and E877 collaborations, and approximately the rapidity and transverse mass distribution of protons at AGS energies. The gradual change from hadronic to string degrees of freedom with increasing bombarding energy can be viewed as a transition from {\it hadronic} to {\it string} matter, i.e. a dissolution of hadrons.Comment: 13 pages, 4 figures, corrected the figures and the tex

Differential Flow of Protons in Au+Au Collisions at AGS Energies

We study the proton sideward and elliptic differential flow for Au+Au collisions at AGS energies (2 -- 8 A cdot GeV) in a microscopic relativistic transport model that includes all baryon resonances up to a mass of 2 GeV as well as string degrees of freedom for the higher hadronic excitations. In order to explore the sensitivity of the various differential flows to the nuclear equation of state (EoS) we use three different parameterizations of the scalar- and vector mean-fields, i.e. NL2 (soft), NL23 (medium) and NL3 (hard), with their momentum dependence fitted to the experimental Schrodinger equivalent potential (at normal nuclear matter density rho_0) up to kinetic energies of 1 GeV. We calculate the excitation function of sideward and elliptic flow within these parameter sets for Au+Au collisions and compare with the recent data from the E895 Collaboration as a function of rapidity, impact parameter and transverse momentum, respectively. We find that the best description of the differential data is provided by a rather 'stiff' EoS at 2 A cdot GeV (NL3) while at higher bombarding energies (4--8 A cdot GeV) a 'medium' EoS leads to the lowest chi^2 with respect to the data. However, the differences in the transverse and elliptic flows (from the different parameter sets) become of minor significance at 4--8 A cdot GeV. We attribute this insensitivity to a similar reduction of the vector potential in all models and to the dominance of string degrees of freedom at these bombarding energies.Comment: 18 pages, 7 figures, submitted for publicatio

Interações Planta-polinizador Em Vegetação De Altitude Na Mata Atlântica

Tropical high-altitude vegetation is unique due to susceptibility to severe weather conditions in relation to lower formations, and by the peculiarity of its flora with many relictual components. Studies on plant-pollinator interactions in high-altitude rocky outcrops and forests of the Atlantic Forest are scarce, but compilation of information allows us to identify some patterns: low frequency of visits, high floral longevity and generalized pollination system. In tropical mountain ecosystems, the degree of generalization of pollination systems in functional (pollinator groups) and ecological (number of species) terms tends to be high, mainly due to the over-representation of certain plant taxa (e.g., Asteraceae in rocky outcrops and Fabaceae, Myrtaceae, Rubiaceae and Sapindaceae in montane forests). Generalized pollination systems and autogamy may be advantageous for tropical high-altitude plants due to the more severe weather conditions (e.g., low temperature), which decrease abundance and limit the activity of pollinators, resulting in lower visitation frequency. Nevertheless, some well represented groups in forests, such as orchids and plants pollinated by hummingbirds and bats, exemplify cases of higher functional specialization, as well as plants with poricidal anthers pollinated by bees in the high-altitude grasslands. However, in rocky outcrops, for some functional groups of pollinators (e.g., hummingbirds, bats, beetles and hawkmoths), the availability of resources does not allow the maintenance of all species throughout the year, favoring possible local or altitudinal migrations. Thus, rocky outcrops and high-altitude forests constitute a unit in the sense of sustaining the pollinator community. Indeed rocky outcrops and high-altitude forests share an evolutionary history at the regional scale since they passed through similar events of expansion and retraction in response to climate changes in the Quaternary. This could explain the complementarity between the two types of vegetation in the use of floral resources by pollinators. Besides the associations identified here, the ecology and evolution of plant-pollinator interactions in high-altitude vegetation of the Atlantic Forest remain poorly understood, making urgent the development of an integrative research program, as well as projects on issues related to climate change and biodiversity conservation. © 2016, Universidade Federal do Rio de Janeiro (UFRJ). All rights reserved.20272

Global Search for New Physics with 2.0/fb at CDF

Data collected in Run II of the Fermilab Tevatron are searched for indications of new electroweak-scale physics. Rather than focusing on particular new physics scenarios, CDF data are analyzed for discrepancies with the standard model prediction. A model-independent approach (Vista) considers gross features of the data, and is sensitive to new large cross-section physics. Further sensitivity to new physics is provided by two additional algorithms: a Bump Hunter searches invariant mass distributions for "bumps" that could indicate resonant production of new particles; and the Sleuth procedure scans for data excesses at large summed transverse momentum. This combined global search for new physics in 2.0/fb of ppbar collisions at sqrt(s)=1.96 TeV reveals no indication of physics beyond the standard model.Comment: 8 pages, 7 figures. Final version which appeared in Physical Review D Rapid Communication

Observation of Orbitally Excited B_s Mesons

We report the first observation of two narrow resonances consistent with states of orbitally excited (L=1) B_s mesons using 1 fb^{-1} of ppbar collisions at sqrt{s} = 1.96 TeV collected with the CDF II detector at the Fermilab Tevatron. We use two-body decays into K^- and B^+ mesons reconstructed as B^+ \to J/\psi K^+, J/\psi \to \mu^+ \mu^- or B^+ \to \bar{D}^0 \pi^+, \bar{D}^0 \to K^+ \pi^-. We deduce the masses of the two states to be m(B_{s1}) = 5829.4 +- 0.7 MeV/c^2 and m(B_{s2}^*) = 5839.7 +- 0.7 MeV/c^2.Comment: Version accepted and published by Phys. Rev. Let