Characterization of emerging European-like porcine reproductive and respiratory syndrome virus isolates in the United States

European-like field isolates of porcine reproductive and respiratory syndrome virus (PRRSV) have recently emerged in North America. The full-length genomic sequence of an index isolate characterized in 1999, strain EuroPRRSV, served as the reference strain for further studies of the evolution and epidemiology of European-like isolates (type 1) in the United States. Strain EuroPRRSV shared 90.1 to 100% amino acid identity with the prototype European strain, Lelystad, within the structural and nonstructural open reading frames (ORFs) and 95.3% overall nucleotide identity. The 5' untranslated region and two nonstructural regions within ORF 1 were closely examined due to significant divergence from strain Lelystad. A 51-bp deletion in a region within ORF 1a, coding for nonstructural protein 2 (NSP2), was observed. Sequence analysis of the structural ORFs 2 to 7 of additional European-like isolates indicated that these isolates share 93% nucleotide identity with one another and 95 to 96% identity with the Lelystad strain but only 70% identity with the North American reference strain VR-2332. Phylogenetic analysis with published PRRSV ORF 3, 5, and 7 nucleotide sequences indicated that these newly emerging isolates form a clade with the Lelystad and United Kingdom PRRSV isolates. Detailed analysis of four of these isolates with a panel of 60 monoclonal antibodies directed against the structural proteins confirmed a recognition pattern that was more consistent with strain Lelystad than with other North American isolates.     

Protocorm-like body formation,stem elongation,and enhanced growth of Anthurium andraeanum ‘Tropical’ plantlet on medium containing silver nanoparticles

In Vitro Cellular & Developmental Biology - Plant - In this study, a new method for shoot regeneration via protocorm-like bodies (PLBs) is described. Shoot proliferation using stem elongation...     

Site selection and behavior of sponge and bivalve borers in shells of the cretaceous oysters exogyra cancellata and pycnodonte mutabilis from delaware,U.S.A

In shells of the oysters Exogyra cancellata and Pycnodonte mutabilis from the Mount Laurel and Marshalltown Formations (Campanian‐Maestrichtian), three‐quarters of all valves bear sponge borings (Entobia isp.) borings and 30% have borings of a lithophagid bivalve (Gastrochaenolites isp.). Non‐random distributions of these euendoliths, documented in this paper, may in part be accounted for by differential survival of sponge and lithophagid larvae and spat in varying circumstances. In addition, exterior shell architectures and post‐mortem orientations of shells are inferred to have prompted active geophobic (antigravity), rugophilic (groove‐seeking), and rheophilic (current‐seeking) behavior that enhanced survivorship of the settling larvae.