Viral forensic genomics reveals the relatedness of classic herpes simplex virus strains KOS, KOS63, and KOS79

Herpes simplex virus 1 (HSV-1) is a widespread global pathogen, of which the strain KOS is one of the most extensively studied. Previous sequence studies revealed that KOS does not cluster with other strains of North American geographic origin, but instead clustered with Asian strains. We sequenced a historical isolate of the original KOS strain, called KOS63, along with a separately isolated strain attributed to the same source individual, termed KOS79. Genomic analyses revealed that KOS63 closely resembled other recently sequenced isolates of KOS and was of Asian origin, but that KOS79 was a genetically unrelated strain that clustered in genetic distance analyses with HSV-1 strains of North American/European origin. These data suggest that the human source of KOS63 and KOS79 could have been infected with two genetically unrelated strains of disparate geographic origins. A PCR RFLP test was developed for rapid identification of these strains

Characterization of Vibrio eltor Typing Phages: Properties of the Eltor Phage e4

Biophysical characteristics of Vibrio eltor phage e4, a key phage in the Vibrio cholerae typing scheme were studied. This icosahedral phage was found to contain 12 structural polypeptides with mol. wt. ranging from 25 000 to 120000. One of these polypeptides of mol. wt. 50000 accounted for most of the structural proteins present and was probably the major phage capsid protein. The phage genome comprised a single linear, doublestranded DNA molecule, 69.2 kbp in length (45.6 × 106 mol. wt.) as determined by electron microscopy and restriction fragment analyses. The G + C content was 34.6~. Electron microscopy data indicated that unlike the DNAs of other cholera phages, phage e4 DNA is not circularly permuted. Adsorption under normal conditions was biphasic with rate constants of 1.02 x 10-9/ml/min up to 60~ adsorption and 3 x 10-1°/ml/min thereafter. Intracellular phage multiplication was characterized by a latent period of 27 min. The burst size was approximately 100 phage particles per infected cel