Isolated thallus-associated compounds from the macroalga Fucus vesiculosus mediate bacterial surface colonization in the field similar to that on the natural alga

This study investigated whether surface-associated compounds isolated from the macroalga Fucus vesiculosus had the potential to mediate microbial and/or macrobial epibiosis similar to that on the natural alga. To selectively yield thallus-associated compounds and avoid contamination by intracellular algal compounds, cell lysis was monitored by surface microscopy of algal cells and chemical profiling of algal surface extracts by coupled gas chromatography mass spectroscopy. The optimized extraction resulted in polar and non-polar algal surface extracts. The non-polar surface extract was immobilized in hydrogel, the polar surface extract was homogeneously perfused through the gel to ensure a temporally constant delivery of polar extract components. During a 7day field trial, bacterial biofilms were formed on control gels and gels featuring polar and/or non-polar extract components. PERMANOVA revealed that bacterial community profiles on controls and on gels featuring polar or non-polar extract were significantly different from the profile on F. vesiculosus, while the profile on the gels bearing both polar and non-polar extracts was not. Moreover, the polar surface extracts inhibited the settlement of barnacle cyprids. Considering the pronounced effects of bacterial biofilms on invertebrate larval settlement, these results suggest that algal surface chemistry affects macrofouling not only directly but also indirectly, via its control of biofilm formation and compositio

Herpesviruses and morbilliviruses of aquatic and terrestrial carnivores

The Herpesviridae represent a family of diverse and complex viruses of vertebrates (Roizman et al., 1992; Roizman, 1996) and are believed to be of comparatively ancient origin (Karlin el al., 1994a; McGeoch et al., 1995). Many mammalian species are host to more than one herpesvirus species. In humans, e.g., an eighth distinct herpesvirus species has recently been discovered (Chang et al., 1994; Moore et aI., 1996). Disease associated with lytic herpesvirus infection in their natural hosts varies considerably from mild, superficial mucocutaneous lesions, acute respiratory disease, benign Iymphoproliferative disorders to fatal generalized infections and congenital malformations (Peterslund, 1991). Besides certain viral factors, immuno-(in)competence of the natural host constitutes a major pathogenic factor (Fawl & Roizman, 1994). Some herpesviruses also display transforming properties (e.g. Meinl et al., 1995; Thorley-Dawson el al., 1996) or act as co-factors in tumorigenesis (Nazarin, 1979; Khanna et al., 1995; Mesri et al., 1996). Herpesviruses characteristically establish life-long latenl infections in their hosts (Stevens, 1994). Periodically, latent (silent) virus can become reactivated leading to limited lytic replication and shedding of infectious particles. Latently infected hosts, therefore, represent the major herpesvirus reservoir

Genetic characterization of the unique short segment of phocid herpesvirus type 1 reveals close relationships among alphaherpesviruses of hosts of the order Carnivora

To further characterize phocid herpesvirus type 1 (PhHV-1) at the molecular level, a cluster of genes comprising the complete unique short (Us) region of PhHV-1 has been cloned and sequenced. Within this region, ORFs were detected that code for the equivalent of the Us 2- protein of herpes simplex virus (HSV), a putative protein kinase, and for the glycoprotein equivalents gG, gD, gI and gE. In addition, two small ORFs downstream of gE, homologous to the Us 8.5 and Us 9 proteins of HSV were identified. Comparative analysis of the ORF encoding the gD equivalent of PhHV-1 identified the corresponding proteins of the alphaherpesviruses canine herpesvirus and, to lesser degree, feline herpesvirus as the closest relatives

Distinction of subtype-specific antibodies against European porcine influenza viruses by indirect ELISA based on recombinant hemagglutinin protein fragment-1

BACKGROUND: Serological investigations of swine influenza virus infections and epidemiological conclusions thereof are challenging due to the complex and regionally variable pattern of co-circulating viral subtypes and lineages and varying vaccination regimes. Detection of subtype-specific antibodies currently depends on hemagglutination inhibition (HI) assays which are difficult to standardize and unsuitable for large scale investigations. METHODS: The nucleocapsid protein (NP) and HA1 fragments of the hemagglutinin protein (HA) of five different lineages (H1N1av, H1N1pdm, H1pdmN2, H1N2, H3N2) of swine influenza viruses were bacterially expressed and used as diagnostic antigens in indirect ELISA. RESULTS: Proteins were co-translationally mono-biotinylated and refolded in vitro into an antigenically authentic conformation. Western blotting and indirect ELISA revealed highly subtype-specific antigenic characteristics of the recombinant HA1 proteins although some cross reactivity especially among antigens of the H1 subtype were evident. Discrimination of antibodies directed against four swine influenza virus subtypes co-circulating in Germany was feasible using the indirect ELISA format. CONCLUSIONS: Bacterially expressed recombinant NP and HA1 swine influenza virus proteins served as antigens in indirect ELISAs and provided an alternative to commercial blocking NP ELISA and HI assays concerning generic (NP-specific) and HA subtype-specific sero-diagnostics, respectively, on a herd basis

Serologic survey for phocid herpesvirus-1 and -2 in marine mammals from Alaska and Russia.

Blood samples were collected from 1,042 marine mammals off the coast of Alaska (USA) and Russia during the period 1978 to 1994. Eight species of pinnipeds were represented. Sera were tested for presence of neutralizing antibodies to both the PB84 isolate of phocid herpesvirus-1 (PhHV-1) and the 7848/Han90 strain of phocid herpesvirus-2 (PhHV-2). Species-specific antibody prevalences ranged from 22% to 77% for PhHV-1 and 11% to 50% for PhHV-2. Species-specific antibody prevalences for PhHV-1 were greater than or equal to prevalences for PhHV-2. For both viruses and each host species, differences in antibody prevalences were not related to: (1) sex, (2) location of capture, or (3) year of collection. Antibody prevalence of PhHV-1 in walruses (Odobenus rosmarus) could be quantitatively predicted as a function of age. These two viruses have distinct biological properties and based on current data the epizootiology of the two viruses is different, as well. No evidence of herpesvirus-induced mortality has been detected in areas included in this survey. Based on results of this survey, neither PhHV-1 nor PhHV-2 are considered significant mortality factors in mammals which inhabit the marine environment off the coast of Alaska or Russia

Monoclonal antibodies specific for the hemagglutinin-neuraminidase protein define neutralizing epitopes specific for Newcastle disease virus genotype 2.VII from Egypt

Background Newcastle disease is a devastating disease in poultry caused by virulent Newcastle disease virus (NDV), a paramyxovirus endemic in many regions of the world despite intensive vaccination. Phylogenetic analyses reveal ongoing evolution of the predominant circulating genotype 2.VII, and the relevance of potential antigenic drift is under discussion. To investigate variation within neutralization-sensitive epitopes within the protein responsible for receptor binding, i.e. the Hemagglutinin-Neuraminidase (HN) spike protein, we were interested in establishing genotype-specific monoclonal antibodies (MAbs). Methods An HN-enriched fraction of a gradient-purified NDV genotype 2.VII was prepared and successfully employed to induce antibodies in BalbC mice that recognize conformationally intact sites reactive by haemagglutination inhibition (HI). For subsequent screening of mouse hybridoma cultures, an NDV-ELISA was established that utilizes Concanavalin A (ConA-ELISA) coupled glycoproteins proven to present conformation-dependent epitopes. Results Six out of nine selected MAbs were able to block receptor binding as demonstrated by HI activity. One MAb recognized an epitope only present in the homologue virus, while four other MAbs showed weak reactivity to selected other genotypes. On the other hand, one broadly cross-reacting MAb reacted with all genotypes tested and resembled the reactivity profile of genotype-specific polyclonal antibody preparations that point to minor antigenic differences between tested NDV genotpyes. Conclusions These results point to the concurrent presence of variable and conserved epitopes within the HN molecule of NDV. The described protocol should help to generate MAbs against a variety of NDV strains and to enable in depth analysis of the antigenic profiles of different genotypes

Phylogenetic evidence of canine distemper virus in Serengeti's lions.

Recently an epizootic, reported to be due to a morbillivirus infection, affected the lion population of the Tanzanian Serengeti National Park. A morbillivirus phosphoprotein (P) gene fragment was amplified by PCR from tissue samples of several affected lions. Sequencing of the amplificates and subsequent phylogenetic analyses revealed that a wild-type strain of canine distemper morbillivirus (CDV) was involved. Vaccination of the local domestic dog population with proven safe CDV vaccines is proposed

Subtyping of Swine Influenza Viruses Using a High-Throughput Real-Time PCR Platform

Influenza A viruses (IAVs) are important human and animal pathogens with high impact on human and animal health. In Denmark, a passive surveillance program for IAV in pigs has been performed since 2011, where screening tests and subsequent subtyping are performed by reverse transcription quantitative real-time PCR (RT-qPCR). A disadvantage of the current subtyping system is that several assays are needed to cover the wide range of circulating subtypes, which makes the system expensive and time-consuming. Therefore, the aim of the present study was to develop a high-throughput method, which could improve surveillance of swine influenza viruses (swIAVs) and lower the costs of virus subtyping. Twelve qPCR assays specific for various hemagglutinin and neuraminidase gene lineages relevant for swIAV and six assays specific for the internal genes of IAV were developed and optimized for the high-throughput qPCR platform BioMark (Fluidigm). The qPCR assays were validated and optimized to run under the same reaction conditions using a 48.48 dynamic array (48.48DA). The sensitivity and specificity was assessed by testing virus isolates and field samples with known subtypes. The results revealed a performance of the swIAV 48.48DA similar to conventional real-time analysis, and furthermore, the specificity of swIAV 48.48DA was very high and without cross reactions between the assays. This high-throughput system provides a cost-effective alternative for subtyping of swIAVs

Experimental Infection of Cattle with Highly Pathogenic Avian Influenza Virus (H5N1)

Four calves were experimentally inoculated with highly pathogenic avian influenza virus A/cat/Germany/R606/2006 (H5N1) isolated from a cat in 2006. All calves remained healthy, but several animals shed low amounts of virus, detected by inoculation of nasal swab fluid into embryonated chicken eggs and onto MDCK cells. All calves seroconverted