CEs Moustiques Veulent Votre Sang“There is a framed poster in the office of virologist Sebastian Lequime, on the campus of the University of Groningen (back). In other words: these mosquitoes want your blood.” It is an old advertisement, from 1928, for the drug fly-tox. That stuff was undoubtedly at least as dangerous as the mosquitoes themselves. “
As a virologist, the Lequime trained in France is happy to break a lance for mosquitoes. “They can’t help it that they sometimes carry pathogens with them. They have had too much bad advertising. Just like viruses.”
Yes, there are also plenty Bad Guys Under the viruses. “SARS-COV-2 has not done their reputation well. Not to mention bird flu, dengue, HIV … but by putting the focus exclusively on those pathogens, you ignore the genius of the group as a whole.”
LEQUIME is, as he immediately admits, a fan. “I Love Viruses“I am infected by it, you could say. In Tours I followed a training as a pharmaceutical scientist. But once I learned how fascinatingly versatile and misunderstood viruses are, I am switched.”
Now he is investigating the evolution of RNA viruses in his own Lequime-Lab-which also includes SARS-COV-2 and the other above viruses-and to the role of, among other things, mosquitoes in it. “A virus is a separate piece of genetic material, in the form of single -strand or double -stranded DNA or RNA, which can only multiply in the cells of living beings. All kinds of subgroups can be distinguished within the umbrella group.”
For example, within the RNA viruses there are the flaviviruses, which form the study object of Lequime and his colleagues. “The pathogenic variants for humans are usually transmitted by the bite of a mosquito or tick and for that reason are also called arboviruses – I know, all those terms are starting to dizzy. But that term stands for Arthropod-Borneso from arthropods. ” Dengue is a flavivirus, just like the Western Virus, Zika, yellow fever … “Those examples have two types of hosts: mosquitoes and people. Even if you also have those in insects.”
The Sebastian Lequime lab.
Photos Jagoda Lasota
Diverse hosts
It is precisely this interaction with very different hosts that makes flaviviruses so fascinating, says Lequime. “Controlling yourself in two mammals – say: a bat and a person – that is a child’s play compared to this. And even the bird flu virus, which can occur in both birds and mammals, it still has relatively easy: that focuses on vertebrates. But replicating yourself in a mosquito and a person? mindblowing. We still don’t fully understand how that can do that. The virus was probably created in the invertebrates and ever started to feel at home with vertebrates through that blood sucking. And then there is the question why mosquitoes can do so much better against dengue than we and the question why one mosquito species is more effective in transferring than the other mosquito species … “
Not knowing something: that is almost daily for a researcher into virus evolution, says Lequime. “Take the age of viruses alone: we have no idea, except that they are very old. There is no last common ancestor of viruses, all those different types have a different history. The flaviviruses probably arose more than 500 million years ago, in a co-evolution-a weapon race as it were-with the true one more.” And then there is that ever constant discussion or viruses. “Most biologists say: no. But some are of the opinion that they do live because they reproduce as a coherent set of genes in their own niche: the body of their host. We are also a collection of genes who want to reproduce – read Richard Dawkins’ The Selfish Gene Just after – so in that sense we look alike. “
How do you investigate the evolution of something that you don’t even know if it lives, and does not know old age? Viruses evolve quickly, hundreds of times faster than animals or plants, says Lequime. “That means that we are almost evolution in real time Being able to follow, and that the distant past makes up less. ” In those ways, he and his colleagues with, among other things, lobe extremiments, bioinformatics and computer models are trying to find out which factors play in the virus evolution. More behavior in virus ecology, so the interaction with their hosts and that is essential information if you want to predict the risk of a pandemic or want to develop medicines. ”
The virus genome is a poem rather than a complete novel
The rapid evolution also means that viruses can adapt efficiently to their host, says Lequime. “They have a small genome, with often only about 11,000 base pairs – so the letters with which the genetic code is written. For comparison: people have more than 3 billion. So the virus genome is a poem rather than a complete novel. But the mutation speed of their genes is gigantically high, and so new variants can quickly arise.”
On the desk of Lequime is a blue, round hug: a soft and cuddly example of a rhinovirus. “A memory that viruses are overall. In birds and mosquitoes, in bacteria, fungi and plants, in you and me …” It is estimated that 9 percent of our genes are created from retroviruses that have added to our genome at a certain moment, he explains. “These so -called endogenous viral elements play a role in our immune response against viruses, but also the placenta is a product of those viruses. In the formation of the placenta, the protein syncytin plays a crucial role, and the gene that codes that protein comes from a retro virus.” We are here thanks to viruses, just want to say Lequime. “They are driving forces behind evolution. Agents of Innovation. We owe them a lot. There are even theories that sex is a reaction to a weapon race with viruses: because of genetic diversity, populations are less susceptible to infections. ”
That way he can continue with positive examples. About the viruses that other viruses attack, for example, the viroph wagons. “They can even protect a host against an infection with another virus.” About oceans, in which viruses inhibit algae blooms and ensure optimum nutrient cycle. Or about the American National Park Yellowstone, where the soil temperature can rise up to 55 degrees Celsius, but where viruses ensure that plants and fungi can still survive.
Even in his spare time, the subject of Lequime does not let go. “In my favorite video game, Plague Inc., you become a virus yourself. There is hardly any better way to empathize with viruses.”
