The Proteome of Biologically Active Membrane Vesicles from Piscirickettsia salmonis LF-89 Type Strain Identifies Plasmid-Encoded Putative Toxins

Indexación: Scopus.Piscirickettsia salmonis is the predominant bacterial pathogen affecting the Chilean salmonid industry. This bacterium is the etiological agent of piscirickettsiosis, a significant fish disease. Membrane vesicles (MVs) released by P. salmonis deliver several virulence factors to host cells. To improve on existing knowledge for the pathogenicity-associated functions of P. salmonis MVs, we studied the proteome of purified MVs from the P. salmonis LF-89 type strain using multidimensional protein identification technology. Initially, the cytotoxicity of different MV concentration purified from P. salmonis LF-89 was confirmed in an in vivo adult zebrafish infection model. The cumulative mortality of zebrafish injected with MVs showed a dose-dependent pattern. Analyses identified 452 proteins of different subcellular origins; most of them were associated with the cytoplasmic compartment and were mainly related to key functions for pathogen survival. Interestingly, previously unidentified putative virulence-related proteins were identified in P. salmonis MVs, such as outer membrane porin F and hemolysin. Additionally, five amino acid sequences corresponding to the Bordetella pertussis toxin subunit 1 and two amino acid sequences corresponding to the heat-labile enterotoxin alpha chain of Escherichia coli were located in the P. salmonis MV proteome. Curiously, these putative toxins were located in a plasmid region of P. salmonis LF-89. Based on the identified proteins, we propose that the protein composition of P. salmonis LF-89 MVs could reflect total protein characteristics of this P. salmonis type strain. © 2017 Oliver, Hernández, Tandberg, Valenzuela, Lagos, Haro, Sánchez, Ruiz, Sanhueza-Oyarzún, Cortés, Villar, Artigues, Winther-Larsen, Avendaño-Herrera and Yáñez.https://www.frontiersin.org/articles/10.3389/fcimb.2017.00420/ful

Hadean geodynamics inferred from time-varying 142Nd/144Nd in the early Earth rock record

Tracking the secular evolution of 142Nd/144Nd anomalies is important towards understanding the crust-mantle dynamics in the early Earth. Excessive scatter in the published data, however, precludes identifying the fine structure of 142Nd/144Nd evolution as the expected variability is on the order of few parts per million. We report ultra-high precision 142Nd/144Nd data for Eoarchean and Palaeoarchean rocks from the Isua Supracrustal Belt (SW Greenland) that show a well-resolved 142Nd/144Nd temporal variability suggesting progressive convective homogenisation of the Hadean Isua depleted mantle. This temporally decreasing 142Nd/144Nd signal provides a direct measure of early mantle dynamics, defining a stirring timescale of <250 Myr consistent with vigorous convective stirring in the early mantle. The 142Nd/144Nd evolution suggests protracted crustal residence times of ~1000-2000 Myr, inconsistent with modern-style plate tectonics in the Archean. In contrast, a stagnant-lid regime punctuated by episodes of mantle overturns accounts for the long life-time estimated here for the Hadean proto-crust

Ferromagnetism and Canted Spin Phase in AlAs/GaMnAs Single Quantum Wells: Monte Carlo Simulation

The magnetic order resulting from a confinement-adapted Ruderman-Kittel-Kasuya-Yosida indirect exchange between magnetic moments in the metallic phase of a AlAs/Ga(1-x)Mn(x)As quantum well is studied by Monte Carlo simulation. This coupling mechanism involves magnetic moments and carriers (holes), both coming from the same Mn(2+) ions. It leads to a paramagnetic, a ferromagnetic, or a canted spin phase, depending on the carrier concentration, and on the magnetic layer width. It is shown that high transition temperatures may be obtained.Comment: 7 figure

Systematics of Malaysian woolly bats (Vespertilionidae: Kerivoula) inferred from mitochondrial, nuclear, karyotypic, and morphological data

Examining species boundaries using data from multiple independent sources is an appropriate and robust method to identify genetically isolated evolutionary units. We used 5 data sets—cytochrome b (Cytb), cytochrome c oxidase (COI), amplified fragment length polymorphisms (AFLPs), karyotypes, and morphology—to estimate phylogenetic relationships and species limits within woolly bats, genus Kerivoula, from Southeast Asia. We genetically analyzed 54 specimens of Kerivoula from Malaysia, assigned to 6 of the 10 species currently reported from the country. Phylogenetic analyses of nuclear AFLPs (33 specimens) and mitochondrial DNA sequences from Cytb (51 specimens) and COI (48 specimens) resulted in similar statistically supported species-level clades with minimal change in branching order. Using comparisons of cranial and dental morphology and original species descriptions, we assigned the resulting phylogenetic clades to K hardwickii, K. intermedia, K. lenis, K. minuta, K. papillosa, K pellucida, and 1 unidentified species. Karyotypes further documented variability among the 6 clades. Five different karyotypes were identified, with 2 species having indistinguishable karyotypes. We compared our COI gene sequence data to 110 specimens of Kerivoula from Southeast Asia made available by researchers of the Barcode of Life Database. Our Cytb and AFLP species identifications were congruent with those in the COI database. Intraspecific geographic variation of about 5–7% sequence divergence was observed in Cytb and COI genes within both K. hardwickii and K. minuta. Relaxed molecular clock analyses indicated a late Oligocene to early Miocene origin of the Kerivoulinae with intraspecific diversification events coinciding with the late Pliocene and Pleistocene epochs in at least 6 species. Specimens from Sabah (northeastern Borneo) showed relatively high genetic divergence compared to those between Peninsular Malaysia and Sarawak (southwestern Borneo), indicating Pleistocene or Pliocene refugia in Borneo. We conclude that at least 1 distinct lineage of Kerivoula is yet to be described from Borneo and that the intraspecific geographic variation in some species agrees with previous studies on the diversification of flora and fauna in Borneo. Key word

Quintessential Maldacena-Maoz Cosmologies

Maldacena and Maoz have proposed a new approach to holographic cosmology based on Euclidean manifolds with disconnected boundaries. This approach appears, however, to be in conflict with the known geometric results [the Witten-Yau theorem and its extensions] on spaces with boundaries of non-negative scalar curvature. We show precisely how the Maldacena-Maoz approach evades these theorems. We also exhibit Maldacena-Maoz cosmologies with [cosmologically] more natural matter content, namely quintessence instead of Yang-Mills fields, thereby demonstrating that these cosmologies do not depend on a special choice of matter to split the Euclidean boundary. We conclude that if our Universe is fundamentally anti-de Sitter-like [with the current acceleration being only temporary], then this may force us to confront the holography of spaces with a connected bulk but a disconnected boundary.Comment: Much improved exposition, exponent in Cai-Galloway theorem fixed, axionic interpretation of scalar explained, JHEP version. 33 pages, 3 eps figure

Unitarity bounds on low scale quantum gravity

We study the unitarity of models with low scale quantum gravity both in four dimensions and in models with a large extra-dimensional volume. We find that models with low scale quantum gravity have problems with unitarity below the scale at which gravity becomes strong. An important consequence of our work is that their first signal at the Large Hadron Collider would not be of a gravitational nature such as graviton emission or small black holes, but rather linked to the mechanism which fixes the unitarity problem. We also study models with scalar fields with non minimal couplings to the Ricci scalar. We consider the strength of gravity in these models and study the consequences for inflation models with non-minimally coupled scalar fields. We show that a single scalar field with a large non-minimal coupling can lower the Planck mass in the TeV region. In that model, it is possible to lower the scale at which gravity becomes strong down to 14 TeV without violating unitarity below that scale.Comment: 15 page

Strings on conifolds from strong coupling dynamics, part I

A method to solve various aspects of the strong coupling expansion of the superconformal field theory duals of AdS_5 x X geometries from first principles is proposed. The main idea is that at strong coupling the configurations that dominate the low energy dynamics of the field theory compactified on a three sphere are given by certain non-trivial semi-classical configurations in the moduli space of vacua. We show that this approach is self-consistent and permits one to express most of the dynamics in terms of an effective N=4 SYM dynamics. This has the advantage that some degrees of freedom that move the configurations away from moduli space can be treated perturbatively, unifying the essential low energy dynamics of all of these theories. We show that with this formalism one can compute the energies of strings in the BMN limit in the Klebanov-Witten theory from field theory considerations, matching the functional form of results found using AdS geometry. This paper also presents various other technical results for the semiclassical treatment of superconformal field theories.Comment: 52 pages, JHEP3 styl

Using Genetics and Morphology to Examine Species Diversity of Old World Bats: Report of a Recent Collection from Malaysia

A three-week field survey was conducted to sample bat species diversity in Malaysia. The survey sampled five localities during August 2006, including one in Peninsular Malaysia and four in Borneo. A total of 259 specimens representing at least 50 species were recorded. Three sampling nights were spent at each locality; four harp traps and 15 mist nets were set most nights. The highest species diversity was recorded in Mount Penrisen (Borneo) with 27 species, whereas the lowest diversity was at Monggis Sub Station and Bako National Park (Borneo) with 13 species each. We added four new geographic records for Sarawak, Malaysian Borneo: Arielulus cuprosus, Hesperoptenus tomesi, Kerivoula lenis, and Myotis adversus; and the second record of Hipposideros doriae in Sarawak. Other findings included a colony of earwigs collected from an Eonycteris major and the documentation of highly developed facial glands on male Hipposideros ater and H. galeritus. Species were identified using traditional skin and skull characteristics as well as mitochondrial cytochrome-b gene sequences that were compared to existing GenBank records. This multifaceted approach, using genetic and morphological identifications, has provided greater resolution to species identification as well as a better understanding of the diversification of Old World Bats from Malaysia. Although in most cases genetic data validated the present taxonomy, there were still a number of cases of cryptic species suggesting an underestimation of the actual biodiversity. This study has demonstrated the value of genetic data in providing an independent test for species boundaries among the 50 species of bats collected (about 40% of the known Malaysian bat fauna)

Understanding biological responses to degraded hydromorphology and multiple stresses. Deliverable 3.2 of REFORM (REstoring rivers FOR effective catchment Management), a Collaborative project (large-scale integrating project) funded by the European Commission within the 7th Framework Programme under Grant Agreement 282656

The aim of this deliverable is to conceptually model and empirically test the response of biota to the effects of both hydromorphological pressures acting in concert with one another or with other types of pressures. Best use is made of existing large national monitoring datasets (Denmark, UK, Finland, France, Germany, Austria & WISER datasets), case studies and modeling to provide evidence of multiple stressors interacting to alter river biota (Biological Quality Elements: BQE)