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British researchers say they have taken a huge step forward in treating deafness after stem cells were used to restore hearing in animals for the first time.
Hearing partially improved when nerves in the ear, which pass sounds into the brain, were rebuilt in gerbils – a UK study in the journal Nature reports.
Getting the same improvement in people would be a shift from being unable to hear traffic to hearing a conversation.
However, treating humans is still a distant prospect.
British researchers say they have taken a huge step forward in treating deafness after stem cells were used to restore hearing in animals for the first time
If you want to listen to the radio or have a chat with a friend your ear has to convert sound waves in the air into electrical signals which the brain will understand.
This happens deep inside the inner ear where vibrations move tiny hairs and this movement creates an electrical signal.
However, in about one in 10 people with profound hearing loss, nerve cells which should pick up the signal are damaged. It is like dropping the baton after the first leg of a relay race.
The aim of researchers at the University of Sheffield was to replace those baton-dropping nerve cells, called spiral ganglion neurons, with new ones.
They used stem cells from a human embryo, which are capable of becoming any other type of cell in the human body from nerve to skin, muscle to kidney.
A chemical soup was added to the stem cells that converted them into cells similar to the spiral ganglion neurons. These were then delicately injected into the inner ears of 18 deaf gerbils.
Over 10 weeks the gerbils’ hearing improved. On average 45% of their hearing range was restored by the end of the study.
Dr. Marcelo Rivolta said: “It would mean going from being so deaf that you wouldn’t be able to hear a lorry or truck in the street to the point where you would be able to hear a conversation.
“It is not a complete cure, they will not be able to hear a whisper, but they would certainly be able to maintain a conversation in a room.”
About a third of the gerbils responded really well to treatment with some regaining up to 90% of their hearing, while just under a third barely responded at all.
Gerbils were used as they are able to hear a similar range of sounds to people, unlike mice which hear higher-pitched sounds.
The researchers detected the improvement in hearing by measuring brainwaves. The gerbils were also tested for only 10 weeks. If this became a treatment in humans then the effect would need to be shown over a much longer term.
There are also questions around the safety and ethics of stem cell treatments which would need to be addressed.
According to US researchers, the rise of inflammatory bowel diseases could be down to our shifting diets causing a “boom in bad bacteria”.
Mouse experiments detailed in the journal Nature linked certain fats, bacteria in the gut and the onset of inflammatory diseases.
The researchers said the high-fat diet changed the way food was digested and encouraged harmful bacteria.
Microbiologists said modifying gut bacteria might treat the disease.
Inflammatory bowel diseases (IBDs) include Crohn’s and ulcerative colitis. When the gut becomes inflamed it can lead to abdominal pain and diarrhoea.
According to US researchers, the rise of inflammatory bowel diseases could be down to our shifting diets causing a "boom in bad bacteria"
The researchers at the University of Chicago said the incidence of the diseases was increasing rapidly.
They used genetically modified mice which were more likely to develop IBDs. One in three developed colitis when fed either low-fat diets or meals high in polyunsaturated fats. This jumped to nearly two in three in those fed a diet high in saturated milk fats, which are in many processed foods.
These saturated fats are hard for the body to digest and it responds by pumping more bile into the gut. This changes the gut environment and leads to a change in the bacteria growing there, the researchers said.
One bacterium in particular, Bilophila wadsworthia, was identified. It thrives in the extra bile produced to break down the fats. It went from being incredibly rare to nearly 6% of all bacteria in the gut in the high-fat diet.
Prof. Eugene Chang, of the University of Chicago, said: “Unfortunately, these can be harmful bacteria. Presented with a rich source of sulphur, they bloom, and when they do, they are capable of activating the immune system of genetically prone individuals.”
However, he said this could lead to possible treatments as the gut bacteria could be “reshaped” without “significantly affecting the lifestyles of individuals who are genetically prone to these diseases”.
Scientists have succeeded to decode the bonobo genome, the biochemical instructions in the ape’s cells that guide the building and maintenance of the animal’s body.
It is the last great ape to have its DNA sequence laid bare, following the chimpanzee, orangutan and gorilla.
Comparisons of all their codes, including the human genome, will shed new light on the biology and evolution of these closely related species.
The sequencing and analysis work is reported in the journal Nature.
It was undertaken by an international team led from the Max Planck Institute (MPI) for Evolutionary Anthropology in Leipzig, Germany.
The samples for study were taken from a female bonobo known as Ulindi which resides in Leipzig zoo.
Scientists have succeeded to decode the bonobo genome, the biochemical instructions in the ape's cells that guide the building and maintenance of the animal's body
Bonobos (Pan paniscus), together with chimpanzees (Pan troglodytes), are the closest living relatives of humans.
If one compares the DNA “letters” in the sequences of all three species, there is only a 1.3% difference between humans and their ape cousins.
The separation between the bonobo and the chimp is smaller still. Only four letters in every thousand is changed.
“Based on the differences that we observe between the genomes, one can actually estimate when the last common ancestor between these species lived,” explained MPI’s Kay Prufer.
“And between chimpanzees and bonobos that is maybe a million years in the past. For the chimps, bonobos, and humans – the common ancestor of all three lived somewhere around four to five million years ago,” he said.
Bonobos and chimpanzees live very near to each other in central Africa, but their populations are separated by the Congo River.
Indeed, it has long been thought that the creation of the river about two million years ago was responsible for the divergence of the species. And the new analysis certainly seems to support that hypothesis, with no significant signal of interbreeding detected in the DNA of the apes.
“It seems there was a very clean split,” said Dr. Kay Prufer.
But as similar as their genomes are, bonobos and chimps do display some quite diverse behaviors.
Chimps are very territorial and resort to aggressive actions to resolve conflicts, whereas bonobos are more placid and will use sex as a tool to settle their differences.
The researchers want to learn something about the origin of these behaviors, and the degree to which they are influenced by genetics.
“That’s the great hope,” said Dr. Kay Prufer.
“If you look at bonobos, chimpanzees and humans, what you can see is that there are some specific characteristics that we share with both of them.
“So, for instance, the non-conceptive sexual behavior is a trait that is certainly shared with bonobos, while the aggressive behavior unfortunately is also a trait that is shared with chimpanzees.
“In a way, it is a question of what the ancestor of all three looked like. Which one actually evolved the new trait here?”
To get at some answers, scientists plan to look more deeply at those parts of the genomes where humans share more similarity to bonobos or chimpanzees. It turns out that that more than 3% of the human genome is more closely related to either the bonobo or the chimpanzee genome than these are to each other.
An international research team has announced that a successful sequencing of the tomato genome will lead to tastier varieties within five years.
They believe that the elusive flavor of home grown tomatoes will by then be widely available in supermarkets.
Writing in the journal Nature, the researchers say the genetic information could reduce the need for pesticides.
The authors believe the genome will also boost conventional breeding techniques over genetic modification.
While the sheer numbers and varieties of tomatoes available in UK shops have increased substantially in the past 20 years, many consumers would complain that this growth has been at the expense of flavor.
Scientists like Professor Graham Seymour at the University of Nottingham would tend to agree.
“In the early 1990s what changed the tomato industry was the use of non-ripening mutant genes, genes that came from natural mutations that have been used to extend shelf life in the fruit.
“But this has been quite a blunt instrument, because when you slow ripening down you also slow down those other processes like flavor development and color development.”
Scientists have announced that a successful sequencing of the tomato genome will lead to tastier varieties within five years
As part of an international team of more than 300 scientists from 14 countries, Prof. Graham Seymour and his colleagues believe that the successful deciphering of the tomato genome will have a major impact on a global industry worth between $30 billion and $40 billion annually.
“Now that we have the genome it will be possible to actually target the genes that control flavor separately from those that control shelf life. So it should be possible in the very near future to have tomatoes that last a long time but develop a very dark red color, are full of phyto chemicals and are much more tasty.”
Another member of the team Dr. Gerard Bishop from Imperial College London says the publication of the genome marks a “step change” in the way we breed tomatoes.
“Yield has been the big driver behind most of the breeding strategies and now the push is to go over to flavor. We now have the ability to breed varieties more quickly, it’s going to provide us with more intricate ways of precisely breeding the varieties we really want.”
And these new varieties will be on the shelves very soon according to Prof. Graham Seymour.
“I only work with a couple of companies but I know that they are putting through some of these new traits and they are going to their elite lines – but all tomato breeding companies will be taking this up now so you would expect to see a number of new products over the next 3-5 years.”
However the publication of the tomato genome will raise fears in some people that scientists will now be able to tinker more easily with the genetic makeup of the fruit.
Back in the early 1990s a genetically modified tomato called the Flavr Savr was the first GM crop licensed for human consumption. It was not a commercial success as public concerns over the technology eventually lead to its demise.
So will the availability of the full genetic sequence and the demand for tastier varieties revitalize the GM effort? Prof. Graham Seymour doesn’t think so.
“It’s very likely at the moment that it will just be better breeding through conventional techniques. The genome sequence allows us to target those gene variants in the wild species and bring them into the cultivated lines and do that relatively effectively.”
Dr. Gerard Bishop agrees that the knowledge gleaned from the genome will boost conventional breeding.
“It will allow us to breed more pesticide resistant varieties. And because some of the wild species come from desert locations, there are going to be genes we can breed in that will help mitigate climate change.”
But will the publication of the genome shed any light on the perennial debate about whether a tomato is a fruit or a vegetable? The question gets short shrift from Prof. Graham Seymour
“It’s botanically a fruit, it’s a berry, that’s it.”
The last of the Great Apes genome has been sequenced after a British research team in Cambridge has deciphered the genetic code of the gorilla.
Researchers can now begin to examine the similarities and differences between the apes, the journal Nature reports.
Genome sequences of humans, chimpanzees and orangutans are already published.
The research team hopes their work will help to uncover genetic mutations that led to language, culture and science.
“I’d like to think that in the next 20 or 30 years we will get a deeper understanding of what happened genetically in our evolutionary history, and of how those genes affect the brain and other properties that make us modern humans,” said Richard Durbin of the Wellcome Trust Sanger Institute, who led the study.
Initial comparisons confirm that chimpanzees are our closest relatives, sharing 99% of our DNA. Gorillas come a close second with 98%, and orangutans third with a 97% share.
That reflects the evolutionary history of apes. Genome comparison indicates that the human lineage separated from orangutans 14 million years ago, gorillas 10 million years ago, and chimps 6 million years ago.
That order of events is not a surprise, but the dates are earlier than many scientists had thought.
Although on average humans are closest to chimps, many of our individual genes are more like those of gorillas.
Among them is a gene that enables us and gorillas to hear better than other apes.
Until now, some scientists had thought that the development of hearing was what enabled us to develop language – but as a result of this research, we now know this theory is wrong.
Fifteen percent of the human genome is closer to the gorilla than the chimpanzee, and 15% of the chimpanzee genome is closer to the gorilla than to humans.
One genetic difference that will be of interest to medical researchers is a mutation that results in dementia in humans, but seems to leave gorillas completely unaffected.
The last of the Great Apes genome has been sequenced after a British research team in Cambridge has deciphered the genetic code of the gorilla
The genome unraveled in the research came from a female western lowland gorilla (Gorilla gorilla gorilla) called Kamilah.
Researchers searched through more than 11,000 genes in her genome, as well as in the published versions of the human, chimp and orangutan genetic codes, for changes important in evolution.
“Our most significant findings reveal not only differences between the species, reflecting millions of years of evolutionary divergence, but also similarities in parallel changes over time since their common ancestor,” said Chris Tyler-Smith, who works with Dr. Richard Durbin.
Comparative studies will also shed more light on the evolution of all the Great Apes; but the key question is whether the bounty of genetic information contains clues to the moment when the first genes emerged that made humans capable of abstract thought.
“This is the question we are all fascinated by,” said Dr. Richard Durbin.
It is unlikely that a single development led to our species’ advance towards modernity, or that all developments along that path were genetic.
Anatomically modern humans (Homo sapiens) emerged around 200,000 years ago, but it was not until about 50,000 years ago that our bigger brains began to make a difference.
Until then, humanity was one among small number of apes in Africa, probably living not very differently from gorillas.
So, something happened very rapidly around that time that led to the emergence of abstract thought, allowing humans to invent advanced tools and use them to shape the environment.
“There will have been genetic factors, but also cultural and historic factors,” said Dr. Richard Durbin.
The one Great Ape not to be sequenced so far is the bonobo, a close relative of the chimp. That project is underway, and scientists expect its genome and that of the chimp to be very similar.
The availability of the genomes of all the Great Apes will help scientists answer what happened over the past 200,000 years to enable our species become what we are now.