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Yeti crabs farmers of the deep sea
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National Environment Research Council (NERC)
THREE’S a crowd, but 700 is just fine if you’re a Yeti. Hot vents in Antarctica’s Southern Ocean are crowded with hairy crabs. Blind and surrounded by freezing water, they huddle close to the vent chimneys that power their ecosystem. Sven Thatje at the University of Southampton, UK, discovered the new species, Kiwa tyleri, when his remote vehicle came across two fields of hydrothermal vents in the Southern Ocean. The crabs were hard to miss, with more than 700 packed per square metre. “It was immediately clear that we had something,” Thatje says. “There are piles of them all over.” K. tyleri is a type of Yeti crab, so called because of the hair-like bristles that cover its body. This coat is thought to help the crabs farm their food – the chemosynthetic bacteria that thrive in the vent’s chemical exhaust. It’s a confined existence. Away from the vent, the water can drop to around 0 °C, which paralyses crabs that stray from their heat source. So the crabs compete for the best farming spots at the chimney bases (PLoS One, doi.org/5rv). Some crabs are more successful than others. A few large males climb up the chimneys, Thatje says. “They probably farm but they also scrape up bacterial mats further up the chimney, which may be a nutritional advantage,” he says.
Touch of flu? Ah, that explains the weird cells in your semen MEN: no need to panic but there are strange round cells floating in your semen. Why? The latest idea is that infections like flu are to blame, by disrupting sperm production. The cells “look like spermatozoa, without the tail”, says Gianpiero Palermo at Weill Cornell Medical College in New York. And as it turns out, that is what most of them are. Palermo and his colleagues analysed semen samples from 4800 men. A quarter of the mystery cells turned out to be
white blood cells, but the other three-quarters had a half-set of chromosomes, like sperm cells. But unlike normal sperm cells, these round cells also contained proteins normally made by sertoli cells, which usually function to nurture the growth of sperm. Together, the findings suggest that most of the round cells are in fact immature sperm that have been engulfed for some reason by sertoli cells, and then sloughed off into the ejaculate, says Palermo, who presented the
findings at the European Society of Human Reproduction and Embryology in Lisbon, Portugal, in June. The team noticed that the number of round cells appeared to peak in the winter, correlating with the flu season in New York State, where the study took place. Palermo reckons flu infections might temporarily disrupt the production of sperm, triggering the formation of the round cells. It is an idea that makes sense, says Allan Pacey at the University of Sheffield, UK. Cultura RM/Jamie Kingham/Getty
Yeti crabs farmers of the deep sea
Dark matter signal goes up in pulsars DARK matter is keeping to the shadows. A potential sign of the mysterious stuff may actually be due to the husks of dead stars. For decades astronomers have suspected the existence of a form of matter, called dark matter, that doesn’t emit or absorb visible light and is five times more abundant in the cosmos than normal matter. Since 2009, data from NASA’s Fermi satellite have shown an unexplained excess of gamma rays at the centre of the Milky Way that look strikingly like dark matter particles annihilating each other and emitting highenergy light in the process. But two independent teams have now concluded that the signals are probably contaminated by thousands of previously undiscovered pulsars, a type of rotating stellar corpse (arxiv. org/abs/1506.05104; arxiv.org/ abs/1506.05124). This is the first indication that so many pulsars are there – and it could kill the dark matter interpretation. “This is good news for pulsar people, but bad news for people that were counting on a dark matter signal,” says Christoph Weniger at the University of Amsterdam in the Netherlands.
The benefits of a diverse background IT’S good to be mixed-up. People whose parents are distantly related are, on average, taller, smarter and better educated than those with closely related parents. It has long been known that children are more likely to suffer from genetic diseases if their parents are close relatives, because they may inherit the same harmful gene variants from their mother and father. To probe the wider implications, Jim Wilson of the University of Edinburgh, UK, and his colleagues analysed genome and life history data from 350,000 people.
They found no link between having closely related parents and most of the traits they looked at, such as cholesterol levels and rates of diabetes. But for height, lung function, cognitive ability and educational attainment there was a strong association. On average, for instance, the children of first cousins have 10 months less formal education than others (Nature, DOI: 10.1038/nature14618). But genetics is just one component of intelligence. “Of course cognition depends on a lot of environmental factors as well,” says Wilson.
4 July 2015 | NewScientist | 17
National Environment Research Council (NERC)
THREE’S a crowd, but 700 is just fine if you’re a Yeti. Hot vents in Antarctica’s Southern Ocean are crowded with hairy crabs. Blind and surrounded by freezing water, they huddle close to the vent chimneys that power their ecosystem. Sven Thatje at the University of Southampton, UK, discovered the new species, Kiwa tyleri, when his remote vehicle came across two fields of hydrothermal vents in the Southern Ocean. The crabs were hard to miss, with more than 700 packed per square metre. “It was immediately clear that we had something,” Thatje says. “There are piles of them all over.” K. tyleri is a type of Yeti crab, so called because of the hair-like bristles that cover its body. This coat is thought to help the crabs farm their food – the chemosynthetic bacteria that thrive in the vent’s chemical exhaust. It’s a confined existence. Away from the vent, the water can drop to around 0 °C, which paralyses crabs that stray from their heat source. So the crabs compete for the best farming spots at the chimney bases (PLoS One, doi.org/5rv). Some crabs are more successful than others. A few large males climb up the chimneys, Thatje says. “They probably farm but they also scrape up bacterial mats further up the chimney, which may be a nutritional advantage,” he says.
Touch of flu? Ah, that explains the weird cells in your semen MEN: no need to panic but there are strange round cells floating in your semen. Why? The latest idea is that infections like flu are to blame, by disrupting sperm production. The cells “look like spermatozoa, without the tail”, says Gianpiero Palermo at Weill Cornell Medical College in New York. And as it turns out, that is what most of them are. Palermo and his colleagues analysed semen samples from 4800 men. A quarter of the mystery cells turned out to be
white blood cells, but the other three-quarters had a half-set of chromosomes, like sperm cells. But unlike normal sperm cells, these round cells also contained proteins normally made by sertoli cells, which usually function to nurture the growth of sperm. Together, the findings suggest that most of the round cells are in fact immature sperm that have been engulfed for some reason by sertoli cells, and then sloughed off into the ejaculate, says Palermo, who presented the
findings at the European Society of Human Reproduction and Embryology in Lisbon, Portugal, in June. The team noticed that the number of round cells appeared to peak in the winter, correlating with the flu season in New York State, where the study took place. Palermo reckons flu infections might temporarily disrupt the production of sperm, triggering the formation of the round cells. It is an idea that makes sense, says Allan Pacey at the University of Sheffield, UK. Cultura RM/Jamie Kingham/Getty
Yeti crabs farmers of the deep sea
Dark matter signal goes up in pulsars DARK matter is keeping to the shadows. A potential sign of the mysterious stuff may actually be due to the husks of dead stars. For decades astronomers have suspected the existence of a form of matter, called dark matter, that doesn’t emit or absorb visible light and is five times more abundant in the cosmos than normal matter. Since 2009, data from NASA’s Fermi satellite have shown an unexplained excess of gamma rays at the centre of the Milky Way that look strikingly like dark matter particles annihilating each other and emitting highenergy light in the process. But two independent teams have now concluded that the signals are probably contaminated by thousands of previously undiscovered pulsars, a type of rotating stellar corpse (arxiv. org/abs/1506.05104; arxiv.org/ abs/1506.05124). This is the first indication that so many pulsars are there – and it could kill the dark matter interpretation. “This is good news for pulsar people, but bad news for people that were counting on a dark matter signal,” says Christoph Weniger at the University of Amsterdam in the Netherlands.
The benefits of a diverse background IT’S good to be mixed-up. People whose parents are distantly related are, on average, taller, smarter and better educated than those with closely related parents. It has long been known that children are more likely to suffer from genetic diseases if their parents are close relatives, because they may inherit the same harmful gene variants from their mother and father. To probe the wider implications, Jim Wilson of the University of Edinburgh, UK, and his colleagues analysed genome and life history data from 350,000 people.
They found no link between having closely related parents and most of the traits they looked at, such as cholesterol levels and rates of diabetes. But for height, lung function, cognitive ability and educational attainment there was a strong association. On average, for instance, the children of first cousins have 10 months less formal education than others (Nature, DOI: 10.1038/nature14618). But genetics is just one component of intelligence. “Of course cognition depends on a lot of environmental factors as well,” says Wilson.
4 July 2015 | NewScientist | 17