401 research outputs found

    Taxonomic revision of the Oligocene percoid fish Oligoserranoides budensis (Heckel, 1856), from the Paratethys and paleobiogeographic comments

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    Small perch-like fishes from the Oligocene of the Paratethys have been traditionally assigned to Serranus budensis (Heckel, 1856). A morphological revision of the holotype and specimens previously assigned to S. budensis from the Outer Carpathians, Poland, is provided herein. They are re-assigned to the species Oligoserranoides budensis (Heckel, 1856) — Percoidei incertae sedis. New specimens assigned to Ol. budensis from the Outer Carpathians, Poland, are introduced. Our results reveal that Ol. budensis is very similar to the species Caucasoserranoides morozkiensis, Carpathoserranoides brnoensis, Carpathoserranoides polonicus and Oligoserranoides comparabilis, and further studies are necessary to revise the validity of those species. Ol. budensis shares many characters with genera Lutjanus and Ocyurus of the superfamily Lutjanoidea. Ol. budensis differs from Lutjanoidea in having a toothless palatine. The palaeobiogeography of Oligocene small perch-like fishes in the Paratethys is presented and discussed

    Taxonomic revision of the Oligocene percoid fish Oligoserranoides budensis (Heckel, 1856), from the Paratethys and paleobiogeographic comments

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    Small perch-like fishes from the Oligocene of the Paratethys were traditionally assigned to Serranus budensis (Heckel, 1856). A new morphological study of the holotype and specimens from the Outer Carpathians, Poland, is provided herein. Oligoserranoides budensis (Heckel, 1856), Percoidei incertae sedis, is revised and compared with other small perch-like fishes from the Oligocene Paratethys. Caucasoserranoides morozkiensis, Carpathoserranoides brnoensis, Carpathoserranoides polonicus and Oligoserranoides comparabilis are very similar to O. budensis and further studies are necessary to clarify the validity of those species. O. budensis is compared with the Oligocene-Lower Miocene Pirsagatia sytchevskayae, the Eocene Jimtylerius temnopterus, Ottaviania mariae,O. leptacanthus, Veranichthys ventralis and the Palaeocene Proserranus lundensis. O. budensis shares many characters with the Lutjanoidea, and differs in a toothless palatine. The palaeobiogeography of Oligocene small perch-like fishes in the Paratethys is presented

    Relativistic Spin-Flavor States in Light Front Dynamics

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    Orthonormal spin-flavor wave functions of Lorentz covariant quark models of the Bakamjian-Thomas type are constructed for nucleon resonances. Three different bases are presented. The manifestly Lorentz covariant Dirac-Melosh basis is related to the Pauli-Melosh basis and the symmetrized Bargmann-Wigner basis that are manifestly orthogonal.Comment: 30 pages, 8 tables, no figs; submitted to Ann.Phys.(NY

    Lymphotoxin-Beta Receptor Blockade Reduces CXCL13 in Lacrimal Glands and Improves Corneal Integrity in the NOD Model of Sjögren\u27s Syndrome

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    In Sjögren\u27s syndrome, keratoconjunctivitis sicca (dry eye) is associated with infiltration of lacrimal glands by leukocytes and consequent losses of tear-fluid production and the integrity of the ocular surface. We investigated the effect of blockade of the lymphotoxin-beta receptor (LTBR) pathway on lacrimal-gland pathology in the NOD mouse model of Sjögren\u27s syndrome

    Contribution of plasmid-encoded peptidase S8 (PrtP) to adhesion and transit in the gut of Lactococcus lactis IBB477 strain

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    The ability of Lactococcus lactis to adhere to the intestinal mucosa can potentially prolong the contact with the host, and therefore favour its persistence in the gut. In the present study, the contribution of plasmid-encoded factors to the adhesive and transit properties of the L. lactis subsp. cremoris IBB477 strain was investigated. Plasmid-cured derivatives as well as deletion mutants were obtained and analysed. Adhesion tests were performed using non-coated polystyrene plates, plates coated with mucin or fibronectin and mucus-secreting HT29-MTX intestinal epithelial cells. The results indicate that two plasmids, pIBB477a and b, are involved in adhesion of the IBB477 strain. One of the genes localised on plasmid pIBB477b (AJ89_14230), which encodes cell wall-associated peptidase S8 (PrtP), mediates adhesion of the IBB477 strain to bare, mucin- and fibronectincoated polystyrene, as well as to HT29-MTX cells. Interactions between bacteria and mucus secreted by HT29- MTX cells were further investigated by fluorescent staining and confocal microscopy. Confocal images showed that IBB477 forms dense clusters embedded in secreted mucus. Finally, the ability of IBB477 strain and its ΔprtP deletion mutant to colonise the gastrointestinal tract of conventional C57Bl/6mice was determined. Both strains were present in the gut for up to 72 h. In summary, adhesion and persistence of IBB477 were analysed by in vitro and in vivo approaches, respectively. Our studies revealed that plasmidic genes encoding cell surface proteins are more involved in the adhesion of IBB477 strain than in the ability to confer a selective advantage in the gut

    Varicellovirus UL 49.5 proteins differentially affect the function of the transporter associated with antigen processing, TAP

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    Cytotoxic T-lymphocytes play an important role in the protection against viral infections, which they detect through the recognition of virus-derived peptides, presented in the context of MHC class I molecules at the surface of the infected cell. The transporter associated with antigen processing (TAP) plays an essential role in MHC class I–restricted antigen presentation, as TAP imports peptides into the ER, where peptide loading of MHC class I molecules takes place. In this study, the UL49.5 proteins of the varicelloviruses bovine herpesvirus 1 (BHV-1), pseudorabies virus (PRV), and equine herpesvirus 1 and 4 (EHV-1 and EHV-4) are characterized as members of a novel class of viral immune evasion proteins. These UL49.5 proteins interfere with MHC class I antigen presentation by blocking the supply of antigenic peptides through inhibition of TAP. BHV-1, PRV, and EHV-1 recombinant viruses lacking UL49.5 no longer interfere with peptide transport. Combined with the observation that the individually expressed UL49.5 proteins block TAP as well, these data indicate that UL49.5 is the viral factor that is both necessary and sufficient to abolish TAP function during productive infection by these viruses. The mechanisms through which the UL49.5 proteins of BHV-1, PRV, EHV-1, and EHV-4 block TAP exhibit surprising diversity. BHV-1 UL49.5 targets TAP for proteasomal degradation, whereas EHV-1 and EHV-4 UL49.5 interfere with the binding of ATP to TAP. In contrast, TAP stability and ATP recruitment are not affected by PRV UL49.5, although it has the capacity to arrest the peptide transporter in a translocation-incompetent state, a property shared with the BHV-1 and EHV-1 UL49.5. Taken together, these results classify the UL49.5 gene products of BHV-1, PRV, EHV-1, and EHV-4 as members of a novel family of viral immune evasion proteins, inhibiting TAP through a variety of mechanisms

    Baryon Current Matrix Elements in a Light-Front Framework

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    Current matrix elements and observables for electro- and photo-excitation of baryons from the nucleon are studied in a light-front framework. Relativistic effects are estimated by comparison to a nonrelativistic model, where we use simple basis states to represent the baryon wavefunctions. Sizeable relativistic effects are found for certain transitions, for example, to radial excitations such as that conventionally used to describe to the Roper resonance. A systematic study shows that the violation of rotational covariance of the baryon transition matrix elements stemming from the use of one-body currents is generally small.Comment: 32 pages, LaTeX, 10 postscript figures, uses epsf.sty; figures uuencoded with uufiles (or available by request in .ps or hardcopy form

    Space-Time Supersymmetry of Extended Fermionic Strings in 2+22 + 2 Dimensions

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    The N=2N=2 fermionic string theory is revisited in light of its recently proposed equivalence to the non-compact N=4N=4 fermionic string model. The issues of space-time Lorentz covariance and supersymmetry for the BRST quantized N=2N=2 strings living in uncompactified 2+22 + 2 dimensions are discussed. The equivalent local quantum supersymmetric field theory appears to be the most transparent way to represent the space-time symmetries of the extended fermionic strings and their interactions. Our considerations support the Siegel's ideas about the presence of SO(2,2)SO(2,2) Lorentz symmetry as well as at least one self-dual space-time supersymmetry in the theory of the N=2(4)N=2(4) fermionic strings, though we do not have a compelling reason to argue about the necessity of the {\it maximal} space-time supersymmetry. The world-sheet arguments about the absence of all string massive modes in the physical spectrum, and the vanishing of all string-loop amplitudes in the Polyakov approach, are given on the basis of general consistency of the theory.Comment: 29 pages, LaTeX, ITP-UH-1/9
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