<p>The virus is only the third “virophage” discovered. The first one, called Sputnik, was discovered in 2008 and the second one, Mavirus, was discovered earlier this year.<br /><br />Viruses reproduce by infecting host cells and using cell’s molecular machinery to make multiple copies of their own genome and to package these genomes into protein shells. A virophage is different in that it targets a host cell that is already infected by a “regular” virus.<br /><br />Prof Cavicchioli’s team found OLV associated with a group of giant “phycodnaviruses” (PV), that infect algae and consequently help control algal blooms. The discovery of a virophage in Organic Lake adds new complexity to the dynamics of the microbial community in the Antarctic system, says Prof Cavicchioli whose team modelled the impact of OLV as a predator in the marine system.<br /><br />“By reducing the number of PVs in the community, OLV shortens the time it takes for the host algae population to recover.<br /><br />Modelling shows that the virophage stimulates secondary production through the microbial loop by reducing overall mortality of the host algal cell after a bloom, and by increasing frequency of blooms during the summer periods.<br /><br />“Antarctic lake systems have evolved mechanisms to cope with long light-dark cycles and a limited food web. In Organic Lake and similar systems, a decrease in PV activity may be instrumental in maintaining the stability of the microbial food web,” he said.<br /></p>
<p>The virus is only the third “virophage” discovered. The first one, called Sputnik, was discovered in 2008 and the second one, Mavirus, was discovered earlier this year.<br /><br />Viruses reproduce by infecting host cells and using cell’s molecular machinery to make multiple copies of their own genome and to package these genomes into protein shells. A virophage is different in that it targets a host cell that is already infected by a “regular” virus.<br /><br />Prof Cavicchioli’s team found OLV associated with a group of giant “phycodnaviruses” (PV), that infect algae and consequently help control algal blooms. The discovery of a virophage in Organic Lake adds new complexity to the dynamics of the microbial community in the Antarctic system, says Prof Cavicchioli whose team modelled the impact of OLV as a predator in the marine system.<br /><br />“By reducing the number of PVs in the community, OLV shortens the time it takes for the host algae population to recover.<br /><br />Modelling shows that the virophage stimulates secondary production through the microbial loop by reducing overall mortality of the host algal cell after a bloom, and by increasing frequency of blooms during the summer periods.<br /><br />“Antarctic lake systems have evolved mechanisms to cope with long light-dark cycles and a limited food web. In Organic Lake and similar systems, a decrease in PV activity may be instrumental in maintaining the stability of the microbial food web,” he said.<br /></p>