Effects of temperature on infectivity and of commercial freezing on survival of the North American strain of viral hemorrhagic septicemia virus (VHSV).

Temperature affected the growth of the North American strain of viral hemorrhagic septicemia virus (VHSV) in experimentally infected cell cultures and in Pacific sardine Sardinops sagax. In addition, commercial freezing significantly reduced the infectivity of VHSV in tissues of experimentally infected sardine. Isolates of VHSV representing the geographic range of North American VHSV replicated in the EPC (Epithelioma papulosum cyprini) cell line at 10, 15 and 20 degrees C, but the more northern isolates from British Columbia, Canada, demonstrated significantly reduced growth at 20 degrees C compared to VHSV from more southern locations (p <0.

Genetic characterization and experimental pathogenesis of Piscirickettsia salmonis isolated from white seabass Atractoscion nobilis.

An intracellular bacterium originally isolated from hatchery-reared juvenile white seabass Atractoscion nobilis in southern California, USA, was identified by sequences of the small and large subunit ribosomal (16S and 23S) DNA and the internal transcribed spacer (ITS) as Piscirickettsia salmonis. Considering all rDNA sequences compared, the white seabass isolate (WSB-98) had a 96.3 to 98.

Development of PCR-based methods for detection of Sphaerothecum destruens in fish tissues.

Single-round and nested polymerase chain reaction (PCR) tests were developed for amplification of a 434 bp fragment of the small subunit ribosomal RNA (18S rRNA) gene from Sphaerothecum destruens, previously known as the rosette agent, an intracellular parasite of salmonid fishes. Both tests have successfully amplified S. destruens-specific DNA from different isolates of S.

The response of c-jun/AP-1 to chronic hypoxia is hypoxia-inducible factor 1 alpha dependent.

Hypoxia (low-oxygen tension) is an important physiological stress that influences responses to a wide range of pathologies, including stroke, infarction, and tumorigenesis. Prolonged or chronic hypoxia stimulates expression of the stress-inducible transcription factor gene c-jun and transient activation of protein kinase and phosphatase activities that regulate c-Jun/AP-1 activity. Here we describe evidence obtained by using wild-type and HIF-1 alpha nullizygous mouse embryonic fibroblasts (mEFs) that the induction of c-jun mRNA expression and c-Jun phosphorylation by prolonged hypoxia are completely dependent on the presence of the oxygen-regulated transcription factor hypoxia-inducible factor 1 alpha (HIF-1 alpha).