giant viruses

Myths, Misconceptions and Debated Theories in Biology

Posted on by Shannon Sindermann

Research studies and novel discoveries continually reshape our understanding of the natural world, often refining—and sometimes contesting—prevailing scientific theories. While this influx of new information is important for expanding knowledge, it can also give rise to myths and misconceptions stemming from biases, media misrepresentations and overgeneralizations. In this blog, we’ll explore misconceptions that blur the lines between fact and fiction, some scientific myths that just won’t go die and theories that scientists can’t stop debating.

Humans Only Use 10% of Their Brain 

This myth, frequently perpetuated through movies like Lucy with Scarlett Johansson and Limitless with Bradely Cooper, has ambiguous roots. Some attribute this pseudoscience to Albert Einstein, despite no recorded record of such a claim, while others associate it with a misinterpretation of William James and his “Reserve Energy Theory” (8). 

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Will Warmer Weather Wake the Sleeping Giant (Viruses)?

Posted on by Gary Kobs

Artist's conception of Mimivirus structure, the first of the giant viruses identified.
Artist’s conception of Mimivirus structure, the first of the giant viruses identified.

Following the discovery of Mimivirus (1) the first virus with a particles large enough to be visible under the light microscope, two additional “giant” viruses infecting Acanthamoeba have been discovered Pandoravirus (2) and Pithovirus sibericum (3), the latter from a 30,000 year old Siberian permafrost. A fourth type was recently isolated from the same sample of permafrost by Legendre et al, and named Mollivirus sibericum (4).

Mollivirus sibericum has an approximately spherical virion (0.6 µm diameter) with a 651kb GC-rich genome that encodes 523 proteins. To further characterize the virus the researchers performed transcromic- and proteomic-based time course experiments.

For the particle proteome and infectious cycle analysis, proteins were extracted and then run a 4–12% polyacrylamide gel, and trypsin digests were performed in-gel before nano LC-MS/MS analysis of the resulting peptides. Proteomic studies of the particle showed that it lacked an embarked transcription apparatus, but revealed an unusual presence of many ribosomal and ribosome-related proteins.

When the researchers explored the proteome during the course of an entire infectious cycle, the relative proportions of Mollivirus-, mitochondrion-, and Acanthamoeba encoded proteins were found to vary consistently with an infectious pattern that preserved the cellular host integrity as long as possible and with the release of newly formed virus particles through exocytosis.

In an interesting footnote, the authors of this study point out the fact that two different viruses retain their infectivity in prehistorical permafrost layers should be a concern in the context of global warming and the potential to expose humans to primeval viruses.

References

1. La Scola, B. et al.   (2003) A giant virus in amoebae. Science  299, 2033.
2. Philippe, N. et al. (2013) Pandoraviruses. Amoeba virus with genomes up to 2.5Mb reaching that of parasitic eukaryotes. Science 341,281–6.
3. Legendre, M. et al. (2014) Thirty thousand year old distant relative of giant icosahedral DNA viruses with a pandoravirus morphology. Proc.Natl. Acad. Sci. 111, 4274–9.
4. Legendre, M. et al. (2015)  In depth study of Mollivirus sibercum, a new 30,000 year old giant virus infecting Acanthamoeba.  Proc. Natl. Acad. Sci. 112, E5327–35 (online).