A team of Japanese researchers has filmed a giant virus infecting a cell using just a light microscope, a tool familiar to high school and university students. The team found evidence that their video enhances student understanding of the virus life cycle.
Infected amoeba cells rupture and explode, spreading the Mimivirus. HPI stands for hours post-infection. Credit: Masaharu Takemura from the Tokyo University of Science, Japan
One of the enduring challenges for biology educators is explaining microscopic processes and making them tangible. Typical viruses are not visible under a light microscope, instead requiring expensive electron microscopes that can only image inactive subjects.
The research team, led by Masaharu Takemura of the Tokyo University of Science, identified Mimivirus, the so-called ‘giant virus’ as large enough to see under a light microscope. Mimivirus particles are 450-800nm, about 100 times smaller than the width of a human hair.
To create a video, the team developed a new cell culture method and a new observation chamber that captured Mimivirus infecting and proliferating inside of its single-celled host, the amoeba Acanthamoeba.
“For the first time in the world, we have succeeded in continuously visualizing the events that are believed to occur in viral infection over a long period of time—such as the proliferation of the virus, its release from cells, and the death of cells during the process,” says Takemura.
Because a light telescope can look at active living things, the video shows how the host Acanthamoeba’s healthy movements slow down as the infection progresses. Eventually the host cell ruptures, spilling viral particles into the surroundings.
Virology is an important topic in biology education and today students come to the classroom with information communicated during the COVID-19 pandemic. When surveyed, the majority of 200 undergraduates at a Japanese university associated the term “virus” with “corona” or “coronavirus”.
When the 200 undergraduates were surveyed two weeks after viewing the video, new word associations with “virus” appeared, including “giant virus”, “living things” and “proliferation.”
“[The video] enhances students’ understanding of virus proliferation mechanisms and highlights the biological significance of viruses, their impact on host cell fate, and their role in ecosystems,” says Takemura.
The research and videos are published in the Journal of Microbiology & Biology Education.
