Tomatoes’ tasteless green gene: Choosing tomatoes for color reduces fruit’s flavor, study finds

Tomatoes’ tasteless green gene

Choosing tomatoes for color reduces fruit’s flavor, study finds
By Roberta Kwok

Modern tomatoes (all-over light green fruits at right) lack the correct version of a gene that helps them make flavorful molecules. In its correct form, the gene results in a tastier tomato with a dark green patch at the top (fruits at left). Credit: Courtesy of Hakan Aktas.

The tomatoes your great-grandparents ate probably tasted little like the ones you eat today. The fruit used to have more flavor. A lot more flavor. In fact, tomatoes “were once so flavorful that you could take one in your hand and eat it straight away just like we regularly eat apples or peaches,” according to plant scientist Alan Bennett. He belongs to a team of international scientists who now think they know one reason why the fruit has lost so much flavor.
Although some unripe tomatoes have a dark green patch near the stem, farmers prefer that their unripe tomatoes are the same shade of green all over. The consistent coloring makes it easier for them to know when the fruit should be picked.
But tomatoes without the dark green patch are also missing an important genetic ingredient that helps the fruit make more sugar and other tasty molecules. So by breeding tomatoes for that consistent color, Bennett’s team says, crop scientists may have accidentally contributed to also making this fruit bland.
“It is a good illustration of unintended consequences,” Harry Klee told Science News. Klee studies tomato flavor at the University of Florida in Gainesville.
Tomatoes make sugars in compartments called chloroplasts. Bennett, who works at the University of California, Davis, and his colleagues found that tomatoes need the correct version of a particular gene (one called SlGLK2) to form chloroplasts properly in the fruit. A gene acts as a biological instruction book that tells cells which molecules to make.
Tomatoes without the dark green tinge have the wrong version of this gene, the researchers report in the June 29 issue of Science. As these fruit ripen, they can’t make as many chloroplasts. And chloroplasts that they do produce are smaller. One result: The tomatoes make less sugar — and don’t taste as good.
Tomatoes also produce gases responsible for some of the odors we associate with the fruit. Even though you only breathe them, these gases affect the way that you perceive flavor. Tomatoes with weak chloroplasts can’t make as much of these gases, further reducing flavor.
But the newfound gene change is “not the whole story of why modern tomatoes are so bad, by a long shot,” Klee told Science News. Tomatoes also taste blander when they are picked too early or stored in the fridge.
Power Words
gene An instruction in an organism’s cells that instructs the cell on which molecules to make.
chloroplast A compartment in a plant cell that turns carbon dioxide and water into sugar and oxygen.

 

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Sweets on the brain: Sugar-free sweeteners fool the body’s internal computer

Sweets on the brain

Sugar-free sweeteners fool the body’s internal computer
By Stephen Ornes

 

 

Many diet sodas are sweetened without sugar, but those sweeteners may fool your brain as well as your taste buds. Credit: ValentynVolkov/iStockphoto

Diet soft drinks usually have no sugar, but that doesn’t mean they’re not sweet. These beverages often contain ingredients that mimic sugar’s sweetness without the big calorie count. In a new study, psychologists from San Diego report that the sugar-free sweeteners confuse not only taste buds but also the brain.
Previous studies have found a surprising connection between gaining weight and drinking diet soda, and the new study may help explain why. The brains of people who regularly drink diet soda get mixed up keeping track of calories, say the scientists. And that deception may unconsciously encourage people to overeat.
Erin Green and Claire Murphy from San Diego State University and the University of California, San Diego, worked on the new study. They gave taste tests to 12 people who rarely or never drink diet soda and 12 who drink the beverage regularly. Each volunteer consumed small amounts of water sweetened with either sugar or saccharin, a popular sugar substitute. The recruits randomly received samples of both types of liquid. While the volunteers drank, the researchers collected images of activity in the tasters’ brains.
Many differences in brain activity emerged that suggested a connection between diet soda consumption and problems with eating appropriately. One of the most important differences was in a region called the caudate head, near the brain center. Previous studies have shown that this region is less active in obese people. Similarly, the new study found that people who regularly drink diet sodas had less activity in this region when they were drinking saccharin.
Scientists have been suspecting for years that artificial sweeteners throw off the brain’s calorie counters. In 2010, another team of scientists showed that when rats were sometimes — but not always — fed foods with sugar-free sweeteners, they ate more food and got fat.
Susan Swithers of Purdue University in West Lafayette, Ind., led that study. She told Science News, “The brain normally uses a learned relationship between sweet taste and the delivery of calories to help it regulate food intake.” But when that relationship gets thrown off, she explained, the brain “suddenly has no idea what to expect.”
Power words
obesity Extremely overweight.
psychology The scientific study of the human mind, especially as it affects behavior.

 

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Dino find ruffles feathers: Nearly-perfect, newfound dinosaur fossil reveals more dinos were feathered than previously thought

Dino find ruffles feathers

Nearly-perfect, newfound dinosaur fossil reveals more dinos were feathered than previously thought
By Stephen Ornes

By Stephen Ornes / July 27, 2012

The skeleton of Sciurumimus albersdoerferi, embedded in a limestone slab, suggests that feathers might have been the norm for dinosaurs. Credit: H. Tischlinger/Jura Museum Eichstatt

A skeleton unearthed in Germany may change the way we think about dinosaurs. The fossil includes the head, body and tail of a type of meat-eating dino called a megalosaur that lived about 150 million years ago. This well-preserved specimen contains something else — feathers that gave the dino a shaggy coat and fuzzy tail.
“It looks like it was a pretty fluffy kind of thing,” Mark Norell told Science News. “Kind of like a baby chick.” Norell, a paleontologist at the American Museum of Natural History in New York City, investigated the new fossil. Paleontologists study ancient rocks, looking for signs of the plants and animals that lived millions of years ago.
Feathered dinos have been discovered before. But previous ones were coelurosaurs, a type of dinosaur closely related to modern birds. Megalosaurs like the newfound fossil are only distantly related to birds. The discovery of feathers on a megalosaur suggests that plumage may have been normal for dinosaurs. (Imagine dinos like T. Rex dressed up as Big Bird.)
Researchers suspect the newfound dinosaur was a young one. It measures only about 70 centimeters (a little less than 28 inches) long, about the width of the aisle on a school bus. Some adult megalosaurs grew to be as much as 10 meters long, the length of an entire school bus. Scientists have named the new species Sciurumimus albersdoerferi.
Feathers aren’t the only reason scientists are celebrating the new fossil. Displaying an open mouth, arched back and curving tail, the intact remains show very clearly what the dinosaur looked like. Plus, the bones aren’t broken. Some even have dinosaur flesh on them.
“It’s a gorgeous specimen,” paleontologist Luis Chiappe of the Natural History Museum of Los Angeles County told Science News. “Probably one of the best meat-eating dinosaurs ever preserved.” Chiappe did not work on the new study.

Viewed under ultraviolet light, the fossilized tail of a recently discovered megalosaur shows
patches of preserved skin in yellow and feathers as faint, bluish scratches. Credit: H. Tischlinger/Jura Museum Eichstatt

The dinosaur’s plumage actually looks more like hair. Scientists call these structures “protofeathers.” Even though they differ in appearance from the feathers on modern birds, the two types are made from the same stuff. Researchers hope to learn what color feathers adorned the young megalosaurus, but to find out they’ll have to break off and analyze a bit of the fossil.
And if you’re a paleontologist with your hands on a nearly-perfect specimen, that’s about the last thing you’d want to do. So they’ll hold off — for now.
Power Words
megalosaurus A large, carnivorous, bipedal (walked on two legs) dinosaur of the mid-Jurassic period, whose remains have been found in Europe.
paleontology The branch of science concerned with fossil animals and plants.
fossil The remains or impression of a prehistoric organism preserved in petrified form or as a mold or cast in rock.
coelurosaur A small, slender, bipedal, carnivorous dinosaur with long forelimbs. Scientists believe birds evolved from coelurosaurs.

 

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Animal buddies: Humans aren’t the only animals that benefit from friends

Animal buddies

Humans aren’t the only animals that benefit from friends
By Stephen Ornes

A recent study found that female baboons that groom each other are more likely to come to each other’s aid, even when they’re unrelated. Credit: Joan Silk, UCLA

Baboons may not chat on the phone, go to the movies or see each other in class. But they still have friends who brighten their days. Baboon buddies may use their long fingers and sometimes even their teeth to clean dirt and bugs out of each other’s fur.
Such grooming sessions are “like getting a hug,” Liza Moscovice told Science News. Moscovice, a biologist at Binghamton University in New York, has studied ways that animals may be generous to one another.
Scientists — and pet owners — have known for a long time that animals can be kind to each other. Elephants may share food with each other, for example. But scientists had assumed until recently that this mostly happens between animals that are closely related. Unrelated animals were thought to be nice to each other for short periods only.
Studies by researchers like Moscovice now indicate this isn’t necessarily true. In 2010, Moscovice and her colleagues published a study showing that female baboons that share good experiences are more likely to help each other in the future.
In the team’s experiment, pairs of wild, unrelated baboons first had a good groom together, picking bugs and dirt off of each other. Later, the scientists played a recording of a call for help from one of the baboons. Upon hearing the recording, the baboon went looking for her friend in the direction of the loudspeaker. This suggests that the pair’s earlier grooming experience formed a true bond of friendship.

Mother and daughter baboons, like the ones shown here, form strong bonds. Credit: Joan Silk, UCLA

Mothers and daughters have the strongest relationships among baboons. Sisters and other female relatives also look out for each other. “Relatives generally help regardless of whether they’ve groomed or interacted recently,” Moscovice told Science News.
But for baboons without female family around, friends can make a big difference in life, Moscovice says. Baboon societies can be fierce and aggressive; dominant animals may control a greater share of food. A female may share food more readily with friends than with individuals she hasn’t groomed or been groomed by.
Other scientists have documented similar friendships among wild horses and chimpanzees. Moscovice says that by studying how friendships form among animals, scientists may learn more about human relationships as well.
Power Words (adapted from the New Oxford American Dictionary)
baboon A large, ground-dwelling monkey with a long, doglike snout and large teeth.
biology The study of living things.

 

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Baboons detect bogus words: Some monkeys know a real word when they see it

Baboons detect bogus words

Some monkeys know a real word when they see it

By Stephen Ornes

This baboon participated in a new study that found the monkeys could tell real words from nonsense strings of letters. Credit: J. Fagot

Baboons may not know what different words mean, but they can tell real words from a nonsense string of letters. A team of researchers recently came to this conclusion after helping some monkeys study written English words.
Don’t worry. We’re not headed for Planet of the Apes. Though fake words didn’t fool the monkeys, the animals didn’t know what any of the words meant. In other words, they weren’t reading. The scientists suspect the monkeys instead picked up on how strings of letters look in real words.
“We think our baboons learned to distinguish between specific combinations of letters that mostly appear in words versus combinations of letters that mostly appear in nonwords,” psychologist Jonathan Grainger from the University of Aix-Marseille in France told Science News. Grainger, who led the new experiment, studies brain functions related to reading.
If Grainger is right, then some current ideas about how we humans learn to read might be wrong. Many scientists assume that matching written letters with their sounds is one of the first steps in learning to read. But the new study suggests that the process might be even more visual. Just as the brain can learn to tell the difference between what a desk looks like and what a lamp looks like, it can learn to tell the difference between the appearance of the letters “a” and “e.”

The baboons in the study reached through holes in a wall to touch the computer screen where words — both real and nonsense — were displayed. Credit: J. Fagot

All primates have the ability to tell objects apart based on what they look like. Grainger and his colleagues propose that this visual ability is important in the early stages of reading. In the new study, the scientists say, the baboons identified which pairs of letters show up more often in real words. (“Ht” is less common in words than “th,” for example.) The monkeys correctly identified real words without knowing how the words sound.
The experiment involved six baboons that went through training programs on touch-screen computers. They received a treat if they touched a cross on the screen after seeing a real word. They also received a treat if they touched an oval shape on the screen after a nonsense word appeared.
As the baboons improved their performances, new words popped up. Over time, the baboons learned to recognize the letter properties of real words like done and vast and nonsense words like dran and virt.
After more than a month of training, most of the animals got pretty good. About three out of every four times, on average, the baboons could correctly tell whether a word was real or nonsense. By the end of the experiment, they could recognize dozens of real words, even when presented with more than 7,000 nonsense words. The highest-scoring monkey identified 308 real words; the lowest-scoring monkey picked out 81.
POWER WORDS (adapted from the New Oxford American Dictionary)
primate A group of mammals that includes lemurs, bush babies, tarsiers, monkeys, apes and humans. Primates have grasping hands and feet, forward-facing eyes and are typically agile tree-climbers.
baboon A large ground-dwelling African monkey with a long, doglike snout and large teeth. Baboons are social animals and live in troops.
psychology The scientific study of the human mind and its functions.

 

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Mammals feel the heat: Scientists predict some animals won’t be able to keep up with Earth’s increasing temperatures

Mammals feel the heat

Scientists predict some animals won’t be able to keep up with Earth’s increasing temperatures
By Stephen Ornes

Scientists say squirrel monkeys may not be able to move to new habitats fast enough to keep up with climate change. Credit: Dave Pape/Wikimedia Commons

It’s getting hotter: The average temperature on Earth has been rising for more than 200 years, with the steepest climbs in recent times. When our planet adjusts like this, so does everything that lives on it. In a new study, scientists from the University of Washington in Seattle set out to investigate how 493 different kinds of mammals might respond to Earth’s warming climate.
The researchers came back with grim news: Many mammals in the Western Hemisphere, which includes North and South America, could face serious problems. (Mammals include animals like dogs, cats, rodents, goats, monkeys and humans. They’re warm-blooded, have hair or fur and usually nurse their young.)
Until now, many biologists assumed that if the environment of some creature became uncomfortable, the animal would move somewhere similar to its preferred habitat — if such habitats continued to exist elsewhere. But for their new study, the scientists examined how likely it was that a species would be able to move to a better site. For instance, was there a mountain or a city the size of Chicago blocking the animal’s path? Or would a relocation require tiny mice to travel hundreds of miles within a short number of years?
Animals that live in parts of the Amazon rain forest may be particularly hard-hit: Nearly half of the mammal species there may not be able to relocate fast enough to keep up with the changing climate of their habitat.

A recent study found that many mammals might have a hard time adjusting to climate change. But scientists say the three-toed sloth has a good chance of relocating to a new home with more suitable temperatures. Credit: Tauchgurke

If species can’t move to a new locale, “they’re going to go extinct. That’s the bottom line,” geographer Nina Hewitt told Science News. Hewitt, of York University in Toronto, studies how plants and animals might respond to climate change. She was not involved in the new work.
Mammals tend to be homebodies: They don’t usually move until they’re ready to have offspring. In the new study, the scientists estimated how far each type of mammal would be able to move to make a new home. They also used 10 different computer programs to evaluate how the climate would likely change between now and the year 2100. The scientists then compared the possible speed of the mammals’ movements with the rate at which their environments would change.
Monkeys, shrews and moles will fare the worst, the researchers reported, while armadillos, anteaters and sloths will be able to fare well. In any given place in the Western Hemisphere, about 9 out of every 100 mammal species may be left homeless within this century by climate change.
Of course, the study didn’t look at every possible scenario. The animals that do move to more comfortable homes may have to face new predators. Or, they may have a harder time finding food. These factors could make their chances of survival far worse.
The new study is not the first to predict how climate change will affect the lives of animals. But it does give biologists some idea of where to look for — and possibly help — species that have to find a new place to live.
Power words
climate change Long-term, significant change in the climate of Earth. It can happen naturally or in response to human activities, including the burning of fossil fuels and clearing of forests.
mammal A warm-blooded, vertebrate animal with hair or fur, the secretion of milk by females for the nourishment of the young, and (typically) the birth of live young.
climate Weather conditions prevailing in an area in general or over a long period.
species A group of living organisms consisting of similar individuals.

 

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Jelly babies: Population of jellyfish-like creatures contains only young animals, no adults

Jelly babies

Population of jellyfish-like creatures contains only young animals, no adults
By Roberta Kwok

A comb jelly is a small animal with tentacles that lives in the ocean. Scientists have found a population of comb jellies that contains only young jellies, no adults. Credit: Cornelia Jaspers

Some animals never grow up. Scientists have discovered that a population of tiny marine creatures near northern Europe contains only larvae, the immature form of the animal. That’s like finding an entire town of kids — and no adults.
The animal is a comb jelly called Mertensia ovum, a jellyfish-like sea creature with a round body and tentacles. Adults of this species can grow as big as 10 centimeters (4 inches) long. But among this newly studied population, researchers couldn’t find any individuals bigger than 1.6 millimeters (less than a tenth of an inch) — the size of a marker pen point.
The team found these jellies during 13 trips to the Baltic Sea, a body of water between Sweden, Finland and Poland. The researchers sampled the critters from four parts of the sea.
In the lab, comb jelly larvae bigger than 0.75 millimeter (about one-thirtieth of an inch) could lay eggs. That means even the young of this species can reproduce.
The researchers think that the larvae are reproducing enough to keep the population going, even though none ever become adults. The study is “actual proof from nature that there is an entire population maintained by larval reproduction,” team member Cornelia Jaspers told Science News. Jaspers is a graduate student at the Centre for Ocean Life at the Technical University of Denmark in Charlottenlund.
The scientists think that the jellies might be reproducing early because a lot of predators are nearby. If many comb jellies get eaten by predators before they reach adulthood, the population could dwindle. So by developing the ability to lay eggs while they’re still young, these jellies can make sure their population doesn’t die out.
This shift toward early reproduction is an example of evolution. Evolution occurs when a species changes over time — usually many generations — improving its chances of survival. For example, an animal might evolve sharper claws or thicker fur.
Many people think that “evolution sort of goes forward. Everything gets bigger and more complicated and smarter,” Mark Martindale told Science News. Martindale is the director of the Kewalo Marine Laboratory at the University of Hawaii at Manoa in Honolulu. But this new research suggests that evolution can sometimes make a species become simpler or smaller.
Power Words
comb jelly A jellyfish-like animal with a round body and tentacles that lives in the ocean.
population A group of individuals from the same species that lives in the same area.
reproduce To create offspring.
evolution A process by which a species changes gradually over generations.

 

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