Viruses are probably the most peculiar `life forms` known to us, with each species having unique characteristics. One thing common to all viruses is that they attack a `host` cell and hijack its machinery, using it for its own replication. A type of large virus, called `giant virus,` has interesting ways of attacking its host organism-an amoeba. Virologists have been trying to understand what makes these viruses so unique for some time now, but to observe them, complex techniques are required. A method called phase-contrast microscopy is commonly used to study all types of cells, including amoebal cells. But, this technique relies heavily on the variation in the conditions of the cell and its background, and sometimes this leads to disruptions in the image produced-for example `halo` (in which the cell is surrounded by a bright light) and `shade-off` (in which the inside of the cell and background are of a similar intensity). This is why, to dig deeper into exactly how giant viruses infect amoebal cells, more efficient cell-tracking techniques are needed. Just earlier this month, scientists from the Tokyo University of Science, led by Professor Masaharu Takemura, had reported the discovery of two new species of pandoravirus and mimivirus-both families of giant viruses infecting amoebae-from a riverbank in Japan. Prof Takemura says that continual discovery of viruses from soil is crucial from the standpoint of understanding the ecology of giant viruses.
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