Adsorption of mycoplasmavirus MV-L2 to Acholeplasma laidlawii: effects of changes in the acyl-chain composition of membrane lipids.

The enveloped mycoplasmavirus MV-L2 and its host Acholeplasma laidlawii JA1 were used to study the ways in which changes in the membrane lipid bilayer affect virus adsorption. The physical state of the membranes was altered by (i) using viruses and bacteria with different membrane lipid acyl-chain compositions, (ii) using incorporation of cholesterol, and (iii) changing the temperature. Adsorption of viruses was strongly dependent on the acyl-chain composition of the virus and the host. Adsorption to homologous hosts was poor, whereas adsorption to hosts with highly different membrane lipid acyl-chain composition was much stronger. We found a heterogeneity within virus populations produced from hosts with different acyl-chain compositions. In a given virus population, various subpopulations differing in acyl-chain composition were found that differed in their ability to adsorb to cells with a specific acyl-chain composition. The adsorption rate increased slightly when cholesterol was present in the viral membranes but decreased considerably when cholesterol was present in the bacterial membranes. The rate of adsorption was temperature dependent with an increase in adsorption rate above 20 degrees C (for hosts with equal amounts of palmitoyl and oleoyl acyl chains). MV-L2 did not adsorb to the persistently L2-infected strain JA1(2R) but adsorbed very well to the virus-resistant strain A(EF22). The physicochemical properties of the lipid matrix of both virus and host are obviously important factors in the adsorption process.