Bite-Size Science: Largest microbe ever discovered, study links animal delicacies at wet markets to 102 viruses

Largest microbe ever discovered could explain the link between prokaryotes and eukaryotes

Microbes are generally supposed to be invisible to the naked eye, but in the Caribbean, a microbe that can grow up to two centimeters has been described, making scientists question what it really means for a cell to be a prokaryote, also known as a single-celled organism. Scientists have named the giant microbe Thiomargarita magnifica, with ‘magnifica’ stemming from the bacterium’s unusually large size — it is about 5000 times the size of most other bacteria.

What makes T. magnifica even more unlike typical bacteria is that its DNA is stored inside a membrane rather than just floating around in the cell. In general, prokaryotes are smaller than eukaryotes, have free-floating DNA and lack complex organelles for higher cell functions. By contrast, eukaryotic cells, like our own, store DNA in the nucleus of the cell, making this trait of the large microbe more like eukaryotes than other prokaryotes.

T. magnifica seems to push the boundaries of the typical prokaryote definition, especially since it contains about 4000 more genes than regular bacteria. These differences are making scientists wonder whether this microbe could provide more evidence to describe the evolutionary transition from prokaryotes to multicellular organisms.

Study finds 102 viruses in animal delicacies at wet markets

A new study has found that many wild animal delicacies contain viruses that can be transmitted to humans. Though none of these viruses are closely related to COVID-19, live animal markets, called ‘wet markets,’ still have the potential to start dangerous virus outbreaks as demonstrated by the current pandemic and the 2001 SARS outbreak.

Researchers found 102 viruses in some animals sold at wet markets in China, including civets, raccoon dogs, badgers, bamboo rats and porcupines. Sixty-five of those pathogens were labeled “high risk” since they had previously been transmitted in between species.

The researchers identified several variations of the Influenza A and B virus, which could theoretically provoke another pandemic since they are becoming more common in other kinds of mammals. The influenza virus’s ability to mutate so quickly in other animals means that it could also mutate to infect humans.

Similar to how our immune systems become weaker when we are stressed or do not get enough sleep, animals sold at wet markets are under significant stress and live in poor conditions, making them more vulnerable to viruses. China has already cracked down on the sales of these animals after the initial SARS outbreak, but many of them were still available before the start of the COVID-19 pandemic. Though it is difficult for sellers to adjust to these bans, in the interest of preventing another pandemic, scientists believe it would be best if the sale of these animals significantly decreased.