Viruslike particles containing knob-associated histidine-rich protein are secreted into the culture medium of Plasmodium falciparum in vitro cultures.

This report describes the isolation of a viruslike particle from in vitro cultures of the human malaria parasite P. falciparum. Electronmicroscopic observations suggest that the particles are liberated into the culture medium by budding from the erythrocyte membrane.

[Isolation of virus-like particles of in vitro cultures of Plasmodium falciparum].

We have isolated virus-like particles from in vitro cultures of the malarial agent Plasmodium falciparum. These particles have a buoyant density of 1.16 g/cm3, contain DNA, and appear to arise from budding structures on the surface of parasitized erythrocytes.

[Change in the envelope of a murine retrovirus produced in the presence of toyocamycin].

Toyocamycin (TMC), an adenosine analog, impairs qualitatively and quantitatively virus production in a cellular system chronically infected by Friend Virus. Viral particles released by cell cultures treated with 0.2 microgram/ml of the drug have lost most of their glycoprotein (gp 70) content.

[Production of Friend virus particles at the surface of cells synchronized by Ficoll gradient centrifugation].

Murine cells continuously producing Friend viral complex were synchronized by Ficoll gradient centrifugation. Cells were isolated from different parts of the gradient and counts of budding particles were performed on ultra-thin sections. No significant differences were noticed, suggesting that viral release is not related to cell cycle.

Replication of Mouse Sarcoma Virus (Moloney) and its helper in a human heteroploid cell line of malignant origin.

A human heteroploid cell line of malignant origin (J111) was infected with Mouse Moloney Sarcoma Virus. [MSV-M(MLV)]. The replication of the virus was demonstrated by different methods.