The world’s commonest protein is a whiz at chemistry
Laguna/Getty
By Bob Holmes in Mesa, Arizona
A resurrected gene, brought back from the dead in the lab, is allowing molecular biologists to travel billions of years into the past to study one of the most significant transitions in Earth’s history.
About 2.5 billion years ago, oxygen began to build up in Earth’s previously anoxic atmosphere as a result of photosynthesis by cyanobacteria and other microbes. This Great Oxygenation Event must have caused an ecological upheaval, because oxygen is such a reactive molecule.
To understand more about this key point in evolution, evolutionary biologist Betül Kacar at Harvard University decided to reconstruct the ancient form of rubisco, the key enzyme in photosynthesis that converts carbon dioxide into the precursors of sugars. Rubisco has been called the most abundant protein on Earth, and its history dates back to the dawn of photosynthesis more than 3 billion years ago.
Advertisement
Kacar and her team compared rubisco gene sequences from modern organisms to infer what the sequence must have been in their common ancestor. By doing that repeatedly, she says, “we can walk back down the branches of the evolutionary tree”.
Rubisco changed much more quickly around the time of the Great Oxygenation than it did either before or after it, Kacar said last week at the Astrobiology Science Conference in Mesa, Arizona.
Read more: Photosynthesis: Shaping the planet
This rapid change must have been driven by the need to adapt to the presence of oxygen, she suggests. The modern rubisco molecule has to be selective because it encounters both oxygen and carbon dioxide, but even so it sometimes goes after the wrong gas. Rubisco from before the Great Oxygenation might have been more lax because it encountered oxygen so infrequently.
Kacar’s team has now synthesised the gene sequences to make the ancient rubisco and is using CRISPR gene-editing technology to insert them into cyanobacteria. The modified bacteria, they hope, will then produce a form of rubisco molecule not seen on Earth for billions of years. “Earth’s past is alive, in a way,” says Kacar.
The team can then compare the functions of the ancient proteins and their modern relatives, to see whether the enzyme did indeed become more selective during the Great Oxygenation Event. The technique adds a new dimension to studies of the past that cannot be gleaned from the geological record, says Kacar.
“What makes Betül’s work really exciting is that she’s actually using these sequences to reconstruct the protein in the laboratory,” says Roger Summons, a geobiologist at the Massachusetts Institute of Technology.
The biggest insights, Summons adds, may come from features of the ancient protein that come as a surprise. “It’s about what you might learn that you can’t even anticipate at this point,” he says.
A common parasite that lives in fish eyeballs seems to be a driver behind the fish’s behaviour, pulling the strings from inside its eyes.
When the parasite is young, it helps its host stay safe from predators. But once the parasite matures, it does everything it can to get that fish eaten by a bird and so continue its __life cycle.
The eye fluke Diplostomum pseudospathaceum has a __life cycle that takes place in three different types of animal. First, parasites mate in a bird’s digestive tract, shedding their eggs in its faeces. The eggs hatch in the water into larvae that seek out freshwater snails to infect. They grow and multiply inside the snails before being released into the water, ready to track down their next host, fish. The parasites then penetrate the skin of fish, and travel to the lens of the eye to hide out and grow. The fish then get eaten by a bird – and the cycle starts again.
Advertisement
Many parasites can change an animal’s behaviour to fit their own needs. Mice infected with the parasite Toxoplasma gondii, for example, lose their fear of cats – the animal the parasite needs to reproduce inside.
The parasitic stage that inhabits fish eyes
Mikhail Gopko
In a 2015 study, Mikhail Gopko at the Severtsov Institute of Ecology and Evolution in Moscow and his colleagues showed that fish infected with immature fluke larvae swam less actively than usual – making themselves less visible to predators – and were harder to catch with a net than uninfected controls.
Now, the same team has tested rainbow trout harbouring mature eye flukes – parasites ready to reproduce inside their bird hosts. The team found that these trout swam more actively than uninfected controls and stayed closer to the water’s surface.
Both traits should make fish more conspicuous to birds. When the researchers simulated a bird attack by making a shadow swoop over the tank, the fish froze – but infected fish resumed swimming sooner than uninfected ones.
Gopko says both studies show that how eye flukes manipulate their host’s behaviour depends on their age. Immature parasites “are too young and innocent to infect a next host”, he says, so their goal is to protect the fish they are living in. Mature parasites, however, are ready to reproduce – and to do so they need to get inside a bird’s gut.
Frozen fish
Some earlier studies suggested fluke-infected fish act differently because of impaired vision. But the authors say vision problems wouldn’t explain changes to unfreezing time, or the opposite effects of mature and immature parasites.
The researchers also tested how long it took fish to unfreeze after attack when they were infected with both mature and immature parasites at once. Their behaviour matched that of fish carrying only mature parasites. When the parasites’ goals conflict, Gopko says, “mature guys are clear winners”.
This fits a pattern of young parasites decreasing their host’s likelihood of being preyed on, while older parasites increase it, says Nina Hafer, a parasitologist at the Max Planck Institute for Evolutionary Biology in Plön, Germany. Few studies have pitted mature and immature parasites against each other in one host, she says.
“It contributes to showing how many traits and species can be affected by host manipulation, which should make it an important factor in how parasites alter the ecological interactions of their hosts,” she says.
Journal reference: Behavioral Ecology and Sociobiology, DOI: 10.1007/s00265-017-2300-x
Read more: The cat made me do it: Is your pet messing with your mind?
The House of Representatives will vote on the American Health Care Act on Thursday.
Republican House Majority Leader Kevin McCarthy told reporters he plans to bring the American Health Care Act to the floor of the House and is confident that the bill will pass.
"Do we have the votes? Yes. Will we pass it? Yes," McCarthy said.
The vote will take place just over a month after House Republicans were forced to pull the AHCA from the floor just minutes before a vote after they were unable to wrangle enough of their members to vote for the bill.
Most projections for the outcome of the vote are close. The New York Times aggregate of unofficial whip counts collected by various media outlets has between 19 and 21 GOP lawmakers publicly against the bill. Due to the universal opposition by Democrats, only 23 Republican members can vote against the AHCA for it to fail.
The move comes after a last-minute effort by the House GOP leadership and the White House to win moderates over on the AHCA.
Centrists had pushed back on an addition to the legislation that allowed states to apply for a waiver to repeal some Obamacare regulations, which some members worried would undermine protections for people with preexisting conditions.
To combat this concern, Rep. Fred Upton on Tuesday release an amendment to provide an additional $8 billion in funds to protect those sick Americans in the event that such a waiver is triggered. Importantly, three of the co-sponsors of the amendment — Reps. Steve Knight, David Valado, and Jeff Denham all from California — were either uncommitted or publicly against the AHCA.
The amendment and a trip to meet with President Donald Trump at the White House was apparently enough to win over Upton and fellow hold-out Rep. Billy Long. Their movement, along with the potential cover it could provide other more moderate members, helped get passage within reach.
Importantly, Upton's extra funding did not lose the support of the conservative House Freedom Caucus which did not support the AHCA when it was first brought to the floor in March.
A source close to the Freedom Caucus told Business Insider that some members of the Caucus had seen legislative text of the Upton amendment.
"The Freedom Caucus will continue to support as long as there are no substantive policy changes," the source said.
The House Rules Committee approved the bill and the amendments in a meeting on Wednesday night, officially opening the way for a full House vote.
Did Mark Selby pull off the greatest sporting comeback in history?
Mark Selby pulled off one of the most astonishing victories in a Crucible final as he landed his third World Championship title, but is it the best in sporting history?
When the 'Jester from Leicester' trailed John Higgins by 10-4 on Sunday evening, Selby had looked beaten, on the scoreboard and in his cheerless demeanour, but a colossal comeback saw him roll to an 18-15 victory.
Victory made him just the fourth player to successfully defend a world title in Sheffield, after Steve Davis, Stephen Hendry and Ronnie O'Sullivan.
Selby: Comeback felt impossible
Mark Selby feared World Championship had gone before Crucible comeback
No player had come back to win from a greater deficit than six frames in a World Championship final since Dennis Taylor trailed Steve Davis by 8-0 and 9-1 in their 1985 classic, but there's more of that later...
Barca make the impossible possible?
Barcelona pulled off the biggest Champions League comeback ever to eliminate Paris Saint-Germain earlier this year.
Faced with a 4-0 deficit following the first leg in Paris, Barca won the second leg 6-1 on Wednesday with three of the goals coming from the 88th minute onwards.
Luis Suarez, Lionel Messi and Neymar (twice) were all among the goals but it took a stabbed finish from Sergi Roberto in the 95th minute to pull off the impossible at the Nou Camp.
No team has ever come from four goals down after the first leg of a European Cup tie - is it the best comeback of all time?
Brady's Super Bowl stunner
"We saw it in the Super Bowl, what is possible in sport," said Barcelona midfielder Ivan Rakitic afterwards, and indeed we did. The New England Patriots became Super Bowl champions once again in February by fighting back from 25 points behind to defeat the Atlanta Falcons 34-28 in overtime.
In an extraordinary finale to the most challenging season of his career, Tom Brady inspired the Patriots and confirmed his right to be regarded as the best quarterback the sport has ever seen with a fifth Super Bowl crown.
Patriots win Super Bowl thriller
Super Bowl LI: New England Patriots 34-28 Atlanta Falcons
Brady rallied the Patriots brilliantly to overturn a 28-3 third quarter deficit, completing a thrilling win on a night of improbable drama at Houston's NRG Stadium,
The miracle of Istanbul
A night Liverpool fans will never forget. Rafa Benitez's side were given a footballing lesson by AC Milan in the first half of the 2005 Champions League final. Trailing 3-0 at the break and looking like being on the wrong end of a hiding, the tide turned in the second half. Captain Steven Gerrard inspired an amazing burst of three goals in six minutes to force extra time - and then penalties when goalkeeper Jerzy Dudek performed some spaghetti-legged magic to help Liverpool conquer Europe for a fifth time.
Miracle of Medinah
Another miracle - this time in golf's Ryder Cup in 2012. Jose Maria Olazabal's Europeans looked dead and buried in Chicago when they trailed the Americans 10-4 going into Sunday's singles. Summoning up the spirit of Seve Ballesteros, though, they silenced the partisan crowd and staged a stunning recovery, culminating in Martin Kaymer sinking the putt that saw the cup remain with Europe.
And Solskjaer has won it...
The 1999 Champions League final in Barcelona saw Sir Alex Ferguson's Manchester United chasing a unique treble. Bayern Munich had led through Mario Basler's early goal and it looked like job done as the game entered stoppage time at the Nou Camp. Enter substitutes Teddy Sheringham and Ole Gunnar Solskjaer, with the former side-footing home the equaliser before Solskjaer nudged home Sheringham's flick into the roof of the net to spark utter jubilation.
The Rumble in the Jungle
One of the most iconic fights in boxing history saw the biggest, baddest heavyweight on the planet, George Foreman, take on the greatest of them all, Muhammad Ali, in Zaire. And it was Ali's 'rope-a-dope' tactics which outfoxed Foreman after being pulverised against the ropes for long periods. Ali had worn his opponent into the ground and by the ninth round, he vacated the ropes to unleash a barrage of punches and send Foreman spinning towards the canvas. Ali showed the world he could still 'float like a butterfly, sting like a bee'.
Botham's Ashes
Back in 1981, Australia were on the verge of going 2-0 up against England in the Test series inside four days at Headingley when Ian Botham strode to the crease. His swashbuckling innings of 149 made the Aussies bat again and Bob Willis ripped through the tourists with figures of 8-43 to seal a remarkable 18-run win. England had become just the second Test team to win after following-on, and that momentum swing helped them go on to a 3-1 Ashes series victory.
Allez les Bleus
Sacre bleu! France found themselves 24-10 down after Jonah Lomu's two tries put New Zealand in total control of their 1999 World Cup semi-final. The pre-tournament favourites looked destined for the final, but then came a sudden Gallic turnaround thanks to a 28-point haul from Christophe Lamaison to leave the All Blacks reeling. Philippe Bernat-Salles sealed a remarkable 43-31 win at Twickenham.
The black ball final
When Dennis Taylor trailed snooker legend Steve Davis 8-0 after the opening session of the 1985 Crucible final, an easy whitewash for the 'Nugget' looked to be on the cards. But Taylor staged an amazing comeback to drag it back to 17-17 and force a nerve-jangling final frame in which he provided the most extraordinary sporting narrative by sinking the final black. The final concluded well after midnight, with more than 18.5 million people - almost a third of the population - glued to their television screens.
Agassi's redemption
Andre Agassi knew the French Open final in 1999 would likely be his last chance at the career Grand Slam and his last chance of winning at Roland Garros. He lost the first set 6-1 in just 19 minutes and quickly found himself two sets down and on the verge of defeat to Andrei Medvedev when the Ukrainian won the next 6-2. But the American fought back in gallant style to win in five and become just the second man, after Rod Laver, to complete a career Grand Slam in the Open Era.
The Machine turns on
Mervyn King looked on course to finally win his first major tournament at a fifth attempt when he opened up a 9-2 lead over his opponent James Wade in the final of the 2014 Unibet Masters in Edinburgh. The King missed eight darts for victory - including an agonising six in leg 17 - before Wade staged a remarkable comeback to win 11-10, taking out a 135 checkout to land the £50,000 prize.
Don't forget to follow us on our app for mobile devices and iPad or our Twitter accounts for news, reports, expert analysis and live blogs.
Maria Sharapova shakes with Kristina Mladenovic after losing to her in Germany
Maria Sharapova suffered her first defeat since returning from a 15-month doping ban to Kristina Mladenovic in the Porsche Grand Prix semi-finals.
Sharapova appeared to be heading to victory in Stuttgart after she raced through the first set in 35 minutes and broke in the second for a 2-0 lead.
However, French world No 19 Mladenovic produced a stunning comeback to secure a 3-6 7-5 6-4 victory in just over two hours, 38 minutes and a place in Sunday's final.
Mladenovic, who has been a vocal critic of Sharapova's return to tennis, celebrates her semi-final win over the former world No 1
The Russian, who had not lost a set so far at the tournament, was playing in her first tournament since serving a ban for a positive test for meldonium at the 2016 Australian Open.
Victory in the semi-finals would have seen Sharapova return to the top 200 and secure entry into the qualifying tournament at the French Open without the need for a wildcard.
However, the five-time Grand Slam winner and two-time Roland Garros champion must now wait until May 16 to see whether she has been awarded a wildcard into the main draw for the Paris tournament.
"I'm not angry, I'd have loved to have used the opportunity when I was ahead in the second set, so I had a bit of a let down which allowed her to get back in the match, gain confidence and play well," said Sharapova.
"If at the start of the week I'd said I'd be in this position, I'd be pretty happy with that.
"The way I played, I was really happy with that. You are never sure what level you are going to come onto the court with, but I feel this is a great base with which I started here."
For those on the move, we will have the French Open covered via our website skysports.com/tennis, our app for mobile devices and iPad, or follow our Twitter account @skysportstennis for news, reports, live blogs and expert analysis with updates on Sky Sports News HQ.
Non-subscribers __can grab a NOW TV Sky Sports Day Pass for just £6.99 or Sky Sports Week Pass for £10.99. No contract. You __can enjoy access to all seven Sky Sports channels and watch on a TV with a NOW TV Box or on a range of devices.
Wimbledon will be hoping Maria Sharapova qualifies for the tournament outright, says Andy Murray
Andy Murray believes Maria Sharapova could be handed a wildcard for Wimbledon if the Russian does not qualify through ranking.
Sharapova, who won at Wimbledon in 2004 as a 17-year-old, is back on the WTA Tour after a 15-month ban for doping and made the semi-finals of the Porsche Tennis Grand Prix in Stuttgart in her first event last week, giving herself a ranking of 262 after collecting 185 points.
The 30-year-old now requires deep runs in her next two tournaments in Madrid and Rome to earn enough points before the Wimbledon qualification deadline.
Sharapova celebrates winning match point against Roberta Vinci during the Porsche Tennis Grand Prix
Murray, who said in March players who have served doping suspensions should not be given tournament wildcards, expects the All England Club to offer Sharapova a lifeline whether or not she makes the cut.
"There might not even be a decision to be made because she might be in the main draw after Madrid or Rome," Murray said at the launch of next month's Queen's tournament on Tuesday.
"I think there's a good chance Wimbledon would give her one to get into qualifiers. I'm not sure what they will do but I'm sure they are hoping they don't have to make the decision.
Murray (right) previously said players who have served doping suspensions, such as Sharapova, should not receive tournament wildcards
"There's a good chance that she __can get in by right, which I'm sure is what she's hoping for and that's what Wimbledon would be hoping for."
Early exits from the Australian Open and Indian Wells, coupled with injury and illness, has meant Murray has had his own concerns to contend with after a stellar finish to last year.
The three-time grand slam winner reached the semi-finals at the Barcelona Open last week, but is now entering a period of the season where he has a high number of points to defend in order to maintain his status.
Murray is adamant the pressure of being No 1 has not contributed to his troubled start to 2017.
"I think that was more like at the end of last year," he said. "All that stuff felt a bit different to me. I'm now getting asked about it every week.
"It's almost like trying to find a reason for why this year hasn't been as good as the end of last year but it did not have anything to do with being world number one, in my opinion.
"I haven't felt different when I go on to the court, I didn't feel different when I was preparing for the Australian Open as I did in previous years. I really don't think it has been anything to do with that.
"Definitely at the end of last year, there was a lot going on. But this year and especially the last few months, I haven't felt any different or any extra pressure when I go on the court.
"Maybe now when you lose as number one, it's a bigger story. It feels like each time you lose, it's treated like more of a surprise.
"But I have lost early in Monte Carlo before, I've lost early in Indian Wells before, I've started clay-court seasons badly, I've had difficult runs and I also wasn't number one, so I really don't think it's to do with that.
"It's been a tricky year so far, and I'm hoping now that I'm through the worst of it and I __can finish strong."
Aljaz Bedene came through qualfying to reach his second ATP final
Aljaz Bedene's bid to win his first ATP final ended in a straight sets defeat to Lucas Pouille in the Hungarian Open in Budapest.
The British No 4 headed into his clash with top seed Pouille on the back of a 16-match winning streak which included back-to-back titles on the second-tier Challenger Tour.
Lucas Pouille claimed his second ATP title and first on clay
However, Bedene, who upset second seed Ivo Karlovic in the quarter-finals, was outclassed as the Frenchman wrapped up a 6-3 6-1 win in an hour and four minutes.
World No 14 Pouille pummelled Slovenian-born Bedene's serve, with the man ranked 68th in the world winning just 25 per cent of points on his second delivery.
Laura Siegemund celebrates with the trophy after beating Kristina Mladenovic
Laura Siegemund was the home-town hero in Stuttgart as she lifted the biggest title of her career at the Porsche Grand Prix.
The German was a surprise finalist 12 months ago but lost out to countrywoman Angelique Kerber.
A repeat looked on the cards when France's Kristina Mladenovic led 4-1 in the deciding tie-break but Siegemund fought back to win 6-1 2-6 7-6 (7-5).
For those on the move, we will have the French Open covered via our website skysports.com/tennis, our app for mobile devices and iPad, or follow our Twitter account @skysportstennis for news, reports, live blogs and expert analysis with updates on Sky Sports News HQ.
Non-subscribers __can grab a NOW TV Sky Sports Day Pass for just £6.99 or Sky Sports Week Pass for £10.99. No contract. You __can enjoy access to all seven Sky Sports channels and watch on a TV with a NOW TV Box or on a range of devices.
