887 research outputs found

    Mapping the domains of CD134 as a functional receptor for feline immunodeficiency virus (FIV)

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    The feline homologue of CD134 (fCD134) is the primary binding receptor for feline immunodeficiency virus (FIV), targeting the virus preferentially to activated CD4+ helper T cells. However, strains of FIV differ in their utilisation of CD134; the prototypic strain PPR, requires a minimal determinant in CRD1 of fCD134 to confer near optimal receptor function while strains such as GL8 require additional determinants in the CD134 CRD2. We map this determinant to a loop in CRD2 governing the interaction between the receptor and its ligand; substitution of amino acids S78N,S79Y,K80E restored full viral receptor activity to the CDR2 of human CD134 in the context of feline CD134 with tyrosine-79 appearing to be the critical residue for restoration of receptor function

    Mapping the domains of CD134 as a functional receptor for feline immunodeficiency virus (FIV)

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    The feline homologue of CD134 (fCD134) is the primary binding receptor for feline immunodeficiency virus (FIV), targeting the virus preferentially to activated CD4+ helper T cells. However, strains of FIV differ in their utilisation of CD134; the prototypic strain PPR, requires a minimal determinant in CRD1 of fCD134 to confer near optimal receptor function while strains such as GL8 require additional determinants in the CD134 CRD2. We map this determinant to a loop in CRD2 governing the interaction between the receptor and its ligand; substitution of amino acids S78N,S79Y,K80E restored full viral receptor activity to the CDR2 of human CD134 in the context of feline CD134 with tyrosine-79 appearing to be the critical residue for restoration of receptor function

    The Oligocene mollusc types of Gaetano Rovereto from Santa Giustina and Sassello (NW Italy).

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    The present paper examines the type specimens of the bivalve and gastropod taxa described by Gaetano ROVERETO in the years 1897-1914 coming from the Oligocene rocks of Santa Giustina and Sassello areas (Molare Formation, Tertiary Piedmont Basin, Central Liguria, NW Italy). These taxa are part of the "Collezione BTP" (BTP Collection) housed at the Dipartimento di Scienze della Terra, dell'Ambiente e della Vita - DISTAV - of the Universit\ue0 di Genova. The collecting sites reported in the ROVERETO's papers and indicated on labels have been reinvestigated in the field. 22 taxa (6 gastropods and 16 bivalves) are revised and re-documented; 6 have been recognized as younger synonyms of other species, the others are valid taxa. The majority of this fauna is restricted to the Oligocene time and to the Tertiary Piedmont Basin

    Quantum versus Semiclassical Description of Selftrapping: Anharmonic Effects

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    Selftrapping has been traditionally studied on the assumption that quasiparticles interact with harmonic phonons and that this interaction is linear in the displacement of the phonon. To complement recent semiclassical studies of anharmonicity and nonlinearity in this context, we present below a fully quantum mechanical analysis of a two-site system, where the oscillator is described by a tunably anharmonic potential, with a square well with infinite walls and the harmonic potential as its extreme limits, and wherein the interaction is nonlinear in the oscillator displacement. We find that even highly anharmonic polarons behave similar to their harmonic counterparts in that selftrapping is preserved for long times in the limit of strong coupling, and that the polaronic tunneling time scale depends exponentially on the polaron binding energy. Further, in agreement, with earlier results related to harmonic polarons, the semiclassical approximation agrees with the full quantum result in the massive oscillator limit of small oscillator frequency and strong quasiparticle-oscillator coupling.Comment: 10 pages, 6 figures, to appear in Phys. Rev.

    THE OLIGOCENE MOLLUSC FAUNA OF THE PIEDMONT BASIN (NORTH-WESTERN ITALY) I. SCAPHOPODA AND ARCHAEOGASTROPODA

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    The aim of the present work is to study the Oligocene Scaphopoda and Archaeogastropoda of the Tertiary Piedmont Basin (T.P.B.), aiming towards an overall revision of the Oligocene mollusc fauna of this Basin. Five taxa of Scaphopoda and twenty-eight taxa of Archaeogastropoda have been analysed; among these a new species of Nerita (Theliostyla) is proposed.&nbsp

    Streamlined design of a self-inactivating feline immunodeficiency virus vector for transducing ex vivo dendritic cells and T lymphocytes.

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    BACKGROUND: Safe and efficient vector systems for delivering antigens or immunomodulatory molecules to dendritic cells (DCs), T lymphocytes or both are considered effective means of eliciting adaptive immune responses and modulating their type, extent, and duration. As a possible tool toward this end, we have developed a self-inactivating vector derived from feline immunodeficiency virus (FIV) showing performance characteristics similar to human immunodeficiency virus-derived vectors but devoid of the safety concerns these vectors have raised. METHODS: The pseudotyped FIV particles were generated with a three-plasmid system consisting of: the packaging construct, providing Gag, Pol and the accessory proteins; the vector(s), basically containing FIV packaging signal (psi), Rev responsive element, R-U5 region at both ends, and the green fluorescent protein as reporter gene; and the Env plasmid, encoding the G protein of vesicular stomatitis virus (VSV-G) or the chimeric RD114 protein. Both packaging and vector constructs were derived from p34TF10, a replication competent molecular clone of FIV. The pseudotyped particles were produced by transient transfection in the Crandell feline fibroblast kidney (CrFK) or the human epithelial (293T) cell line. RESULTS: To broaden its species tropism, the final vector construct was achieved through a series of intermediate constructs bearing a longer psi, the FIV central polypurin tract sequence (cPPT), or the woodchuck hepatitis post-regulatory element (WPRE). These constructs were compared for efficiency and duration of transduction in CrFK or 293T cells and in the murine fibroblast cell line NIH-3T3. Whereas psi elongation and cPPT addition did not bring any obvious benefit, insertion of WPRE downstream GFP greatly improved vector performances. To maximize the efficiency of transduction for ex-vivo murine DCs and T-lymphocytes, this construct was tested with VSV-G or RD114 and using different transduction protocols. The results indicated that the FIV construct derived herein stably transduced both cell types, provided that appropriate vector makeup and transduction protocol were used. Further, transduced DCs underwent changes suggestive of an induced maturation. CONCLUSION: In contrast to previously described FIV vectors that were poorly efficient in delivering genetic material to DCs and T lymphocytes, the vector developed herein has potential for use in experimental immunization strategies

    Development of Feline Immunodeficiency Virus ORF-A (tat) Mutants: In Vitro and in Vivo Characterization

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    AbstractA functional ORF-A is essential for efficient feline immunodeficiency virus replication in lymphocytes. We have characterized a series of mutants of the Petaluma strain, derived from p34TF10 and having different combinations of stop codons and increasingly long deletions in ORF-A. Six clones proved fully replicative in fibroblastoid Crandell feline kidney cells and monocyte-derived macrophage cultures but failed to replicate in T cell lines and primary lymphoblasts. Cats inoculated with three selected mutants had considerably milder infections than controls given intact ORF-A virus. In vivo, the mutants maintained growth properties similar to those in vitro for at least 7 months, except that replication in lymphoid cells was strongly reduced but not ablated. One mutant underwent extensive ORF-A changes without, however, reverting to wild-type. Antiviral immune responses were feeble in all cats, suggesting that viral loads were too low to represent a sufficiently powerful antigenic stimulus

    Longitudinal study of Salmonella infection in four Italian farrow-to finish swine herds

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    A longitudinal study of Salmonella enterica infection was carried out in 4 Italian farrow-to-finish swine herds. In each herd 5 litters were randomly selected and in each litter 6 piglets ear tagged. Thus, on each farm 30 pigs were included in the study. Individual blood samples were collected for serologic examination at weaning from all piglets and in the same day from all sows 1n the farrowing unit. Piglets were bled again at approximately 60, 90, 150, 210 and 270 days of life with the last blood sample collected at slaughtering. In one herd, in which the duration of productive cycle was about 12 months, the last blood samples was collected at 350 days of life. 5 pen pooled faecal samples were collected from each herd for bacteriological examination with the same time schedule of blood samples. At slaughtering mesenteric lymph nodes were collected from each ear tagged pig. Sera-prevalence (cutoff S/P ratio 0,25) in sows varied from 93,8% to 100%. In all herds sera-prevalence in piglets showed a similar profile with complete decline of maternal antibodies at day 60 and clear sera-conversion between day 90 and day 150. The peak of sera-prevalence was observed between day 210 and day 270. Sera-prevalence at slaughtering varied from 66% to 100%. Salmonella was isolated from faecal samples in 3 out of 4 herds. No Salmonella was isolated from mesenteric lymph nodes at slaughter in 2 herds. Culture prevalence from mesenteric lymph nodes in the other herds was respectively 3,3% and 30%. This longitudinal study provides original information about epidemiological dynamics of Salmonella enterica infection in Italian swine herds in consideration of the typical longer fattening cycles

    Identification of a Brainstem Circuit Regulating Visual Cortical State in Parallel with Locomotion

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    SummarySensory processing is dependent upon behavioral state. In mice, locomotion is accompanied by changes in cortical state and enhanced visual responses. Although recent studies have begun to elucidate intrinsic cortical mechanisms underlying this effect, the neural circuits that initially couple locomotion to cortical processing are unknown. The mesencephalic locomotor region (MLR) has been shown to be capable of initiating running and is associated with the ascending reticular activating system. Here, we find that optogenetic stimulation of the MLR in awake, head-fixed mice can induce both locomotion and increases in the gain of cortical responses. MLR stimulation below the threshold for overt movement similarly changed cortical processing, revealing that MLR’s effects on cortex are dissociable from locomotion. Likewise, stimulation of MLR projections to the basal forebrain also enhanced cortical responses, suggesting a pathway linking the MLR to cortex. These studies demonstrate that the MLR regulates cortical state in parallel with locomotion
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