During gradient purification of herpes simplex virus type 1 (HSV-1) two bands of particles were observed: a sharp lower band and a more diffuse upper band. The lower band contained almost exclusively HSV-1 virions (H particles) whereas the upper band consisted of membrane-enclosed particles (L particles). These L particles resembled the virions in appearance, but lacked the viral nucleocapsid and were not infectious. Many polypeptides of the viral envelope and the tegument were common to both types of particles. The H particles had polypeptide profiles typical of HSV virions. The L particles contained at least three phosphoproteins (175K, 92K and 55K) and a further two phosphorylated polypeptides not normally observed in virion profiles which comigrated with the 134K and 60K glycoproteins. This clearly indicates that the novel L particles were not merely virions which had formed without the inclusion of a nucleocapsid or virions which had subsequently lost their nucleocapsid during preparative handling. Thus these novel L particles are genuine products of the infectious processes occurring when HSV-1 replicates.

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SUMMARYThe concentration of phospholipids in pigmented Rhodopseudornonas spheroides was higher than that in organisms lacking the photosynthetic pigments ; the amounts of lipid phosphorus/mg. protein were, respectively, 157 and 90 mpmoles. Phosphatidylethanolamine comprised about 40 yo of the phospholipids, the remainder consisting of phosphatidic acid, phosphatidylglycerol and phosphatidylcholine. The phospholipids were confined to the membrane fraction of the organisms. As organisms adapted from the non-pigmented to the pigmented state the amount of lipid phosphorus/mg. protein increased. Experiments with radioactive phosphate showed phosphatidyl glycerol to incorporate label more rapidly than the other phospholipids. It is suggested that the formation of the photosynthetic pigments may be accompanied by modifications to the membrane structure so that it can accommodate more phospholipids.