According to the latest estimates, Covid-19 may be responsible for more than 18 million deaths worldwide. While infectious diseases like this have devastated humanity, it may be wrong to assume they are always antithetical to our survival and flourishing as a species. Otherwise, why would ancient pathogens such as malaria (of the falciparum type), cholera, typhoid, measles, and influenza A persist as human-only diseases - and why have we not evolved immunity to them? That is a question Professor Ajit and Nissi Varki (a husband and wife team) and colleagues at their lab at the University of California, San Diego, have been asking for several decades. The answer, they believe, lies in the complex array of sugar chains called glycans that decorate the surfaces of cells, and the sugar molecules known as sialic acids that cap most of these chains. These terminal sugar chains are involved in everything from the regulation of immune responses to adaptations that may have played a key role in human evolution, such as the ability of our early hominin ancestors to run for longer without becoming fatigued advantage when pursuing prey.
Ajit Varki first became interested in sialic acids and glycobiology in the early 1980s, when he was treating a patient who had suffered an adverse immune response to a therapeutic horse serum used to treat a type of anemia. Rather than the immune response being directed against the presence of foreign proteins - then the standard explanation in biology textbooks - Varki discovered it was because of the sialic acids on the horse proteins, which was surprising as every vertebrate, including humans, can make sialic acids.
Denne historien er fra December 15, 2023-utgaven av The Guardian Weekly.
Start din 7-dagers gratis prøveperiode på Magzter GOLD for å få tilgang til tusenvis av utvalgte premiumhistorier og 9000+ magasiner og aviser.
Allerede abonnent ? Logg på
Denne historien er fra December 15, 2023-utgaven av The Guardian Weekly.
Start din 7-dagers gratis prøveperiode på Magzter GOLD for å få tilgang til tusenvis av utvalgte premiumhistorier og 9000+ magasiner og aviser.
Allerede abonnent? Logg på
If kids get protected from online harm, how about the rest of us?
The Australian government has proposed a ban on social media for all citizens under 16.
'It's not drought - it's looting'
Spain is increasingly either parched or flooded - and one group is profiting from these extremes: the thirsty multinational companies forcing angry citizens to pay for water in bottles.
Life in the grey Zone
Neonatal care has advanced so far that babies born as early as 21 weeks have survived. But is this type of care always the right thing to do?
Out of tune? Band Aid under fire for Africa tropes as it turns 40
Forty years ago this month, a group of pop stars gathered at a west London studio to record a single that would raise millions, inspire further starry projects, and ultimately change charity fundraising in the UK.
Deaths shine spotlight on risks of drinking on party trail
Vang Vieng is an unlikely party hub. Surrounded by striking limestone mountains and caves in central Laos, it morphed from a small farming town to a hedonistic tourist destination in the early 2000s.
Different strokes My strange and emotional week with an AI pet
Moflin can develop a personality and build a rapport with its owner - and doesn't need food or exercise. But is it comforting or alienating?
Strike zone Waking up to the rising threat of lightning
When the Barbados National Archives, home to one of the world's most significant collections of documents from the transatlantic slave trade, reported in June that it had been struck by lightning, it received sympathy and offers of support locally and internationally.
Cheap pints and sticky carpets: the old-school pub is back
In the Palm Tree pub, east London, barman Alf is taking only cash at the rattling 1960s till.
Brain gain Can a radical tax scheme convince the country's brightest to stay?
In the autumn of 2018, I moved to Lisbon for a month-long course at the Universidade .de Lisboa.
Fear and sympathy in small town divided over asylum camp
A year after anti-immigration riots, a site for asylum seekers faces hostility while some locals try to help new arrivals
