124 research outputs found

    Faunistic Composition, Ecological Properties and Zoogeographical Composition of the Family Elateridae (Coleoptera) of the Central Anatolian Region of Turkey

    Get PDF
    The focus of this study was to understand the faunistic composition, ecological properties and zoogeographical composition of Elateridae (Coleoptera) of the Central Anatolian region. 72 species belonging to seven subfamilies and 25 genera were identified. The major part of the Elateridae fauna of the Central Anatolian region is formed by the subfamilies Elaterinae and Cardiophorinae. The genus Cardiophorus was the most species-rich genus. The species composition of the Elateridae fauna of the Central Anatolian region is partially consistent with known Elateridae fauna of Turkey. The Central Anatolian region shares most species with the European part of the Western Palaearctic as does the Elateridae fauna of Turkey. Detailed localities of nine species are given for the first time for Turkey, with emphasis on the Central Anatolian region

    Molecular Epidemiology and Evolution of Human Respiratory Syncytial Virus and Human Metapneumovirus

    Get PDF
    Human respiratory syncytial virus (HRSV) and human metapneumovirus (HMPV) are ubiquitous respiratory pathogens of the Pneumovirinae subfamily of the Paramyxoviridae. Two major surface antigens are expressed by both viruses; the highly conserved fusion (F) protein, and the extremely diverse attachment (G) glycoprotein. Both viruses comprise two genetic groups, A and B. Circulation frequencies of the two genetic groups fluctuate for both viruses, giving rise to frequently observed switching of the predominantly circulating group. Nucleotide sequence data for the F and G gene regions of HRSV and HMPV variants from the UK, the Netherlands, Bangkok and data available from Genbank were used to identify clades of both viruses. Several contemporary circulating clades of HRSV and HMPV were identified by phylogenetic reconstructions. The molecular epidemiology and evolutionary dynamics of clades were modelled in parallel. Times of origin were determined and positively selected sites were identified. Sustained circulation of contemporary clades of both viruses for decades and their global dissemination demonstrated that switching of the predominant genetic group did not arise through the emergence of novel lineages each respiratory season, but through the fluctuating circulation frequencies of pre-existing lineages which undergo proliferative and eclipse phases. An abundance of sites were identified as positively selected within the G protein but not the F protein of both viruses. For HRSV, these were discordant with previously identified residues under selection, suggesting the virus can evade immune responses by generating diversity at multiple sites within linear epitopes. For both viruses, different sites were identified as positively selected between genetic groups

    Antibody Evasion by a Gammaherpesvirus O-Glycan Shield

    Get PDF
    All gammaherpesviruses encode a major glycoprotein homologous to the Epstein-Barr virus gp350. These glycoproteins are often involved in cell binding, and some provide neutralization targets. However, the capacity of gammaherpesviruses for long-term transmission from immune hosts implies that in vivo neutralization is incomplete. In this study, we used Bovine Herpesvirus 4 (BoHV-4) to determine how its gp350 homolog - gp180 - contributes to virus replication and neutralization. A lack of gp180 had no impact on the establishment and maintenance of BoHV-4 latency, but markedly sensitized virions to neutralization by immune sera. Antibody had greater access to gB, gH and gL on gp180-deficient virions, including neutralization epitopes. Gp180 appears to be highly O-glycosylated, and removing O-linked glycans from virions also sensitized them to neutralization. It therefore appeared that gp180 provides part of a glycan shield for otherwise vulnerable viral epitopes. Interestingly, this O-glycan shield could be exploited for neutralization by lectins and carbohydrate-specific antibody. The conservation of O-glycosylation sites in all gp350 homologs suggests that this is a general evasion mechanism that may also provide a therapeutic target

    Recurrent Signature Patterns in HIV-1 B Clade Envelope Glycoproteins Associated with either Early or Chronic Infections

    Get PDF
    Here we have identified HIV-1 B clade Envelope (Env) amino acid signatures from early in infection that may be favored at transmission, as well as patterns of recurrent mutation in chronic infection that may reflect common pathways of immune evasion. To accomplish this, we compared thousands of sequences derived by single genome amplification from several hundred individuals that were sampled either early in infection or were chronically infected. Samples were divided at the outset into hypothesis-forming and validation sets, and we used phylogenetically corrected statistical strategies to identify signatures, systematically scanning all of Env. Signatures included single amino acids, glycosylation motifs, and multi-site patterns based on functional or structural groupings of amino acids. We identified signatures near the CCR5 co-receptor-binding region, near the CD4 binding site, and in the signal peptide and cytoplasmic domain, which may influence Env expression and processing. Two signatures patterns associated with transmission were particularly interesting. The first was the most statistically robust signature, located in position 12 in the signal peptide. The second was the loss of an N-linked glycosylation site at positions 413–415; the presence of this site has been recently found to be associated with escape from potent and broad neutralizing antibodies, consistent with enabling a common pathway for immune escape during chronic infection. Its recurrent loss in early infection suggests it may impact fitness at the time of transmission or during early viral expansion. The signature patterns we identified implicate Env expression levels in selection at viral transmission or in early expansion, and suggest that immune evasion patterns that recur in many individuals during chronic infection when antibodies are present can be selected against when the infection is being established prior to the adaptive immune response

    Immunization with Single-Cycle SIV Significantly Reduces Viral Loads After an Intravenous Challenge with SIVmac239

    Get PDF
    Strains of simian immunodeficiency virus (SIV) that are limited to a single cycle of infection were evaluated for the ability to elicit protective immunity against wild-type SIVmac239 infection of rhesus macaques by two different vaccine regimens. Six animals were inoculated at 8-week intervals with 6 identical doses consisting of a mixture of three different envelope variants of single-cycle SIV (scSIV). Six additional animals were primed with a mixture of cytoplasmic domain-truncated envelope variants of scSIV and boosted with two doses of vesicular stomatitis virus glycoprotein (VSV G) trans-complemented scSIV. While both regimens elicited detectable virus-specific T cell responses, SIV-specific T cell frequencies were more than 10-fold higher after boosting with VSV G trans-complemented scSIV (VSV G scSIV). Broad T cell recognition of multiple viral antigens and Gag-specific CD4+ T cell responses were also observed after boosting with VSV G scSIV. With the exception of a single animal in the repeated immunization group, all of the animals became infected following an intravenous challenge with SIVmac239. However, significantly lower viral loads and higher memory CD4+ T cell counts were observed in both immunized groups relative to an unvaccinated control group. Indeed, both scSIV immunization regimens resulted in containment of SIVmac239 replication after challenge that was as good as, if not better than, what has been achieved by other non-persisting vaccine vectors that have been evaluated in this challenge model. Nevertheless, the extent of protection afforded by scSIV was not as good as typically conferred by persistent infection with live, attenuated SIV. These observations have potentially important implications to the design of an effective AIDS vaccine, since they suggest that ongoing stimulation of virus-specific immune responses may be essential to achieving the degree of protection afforded by live, attenuated SIV

    Organizational and corporate identity revisited: Towards a comprehensive understanding of identity in business

    Get PDF
    ABSTRACT: Purpose – This paper provides a comprehensive and integrative review of academic literature analyzing identity in business. The literature review proposed by the authors helps clearing up theoretical and practical understanding of this concept. Design/methodology/approach – A review of existing literature in organizational behavior and marketing fields is proposed to clarify the meaning of organizational and corporate identity. On the basis of this review, the authors also identify an integrative perspective proposed for managers to identify and effectively manage all dimensions of their business identities. Findings – Literature on the identity of businesses is extensive and blurred, failing to provide useful guidance for practitioners to manage this concept. A new approach proposes understanding this kind of identity as a global concept that integrates proposals from diverse research fields in order to take advantage of cross-fertilization. Practical implications – This research allows identity and communication managers to understand dimensions of business identity for a more effective management of this concept in their organizations. Originality/value – The line of research that proposes an integrative multidisciplinary approach to the study of identity in business is quite new and, as so, it still needs further contributions to clarify this nascent domain. In this paper, the authors also classify previous studies on business identity according to the theoretical approach they assume just as no other research has done before. Borra
    • …
    corecore