JCVI: First Self-Replicating, Synthetic Bacterial Cell Constructed by J. Craig Venter Institute Researchers
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Wednesday, May 26, 2010
Monday, May 24, 2010
PhD Admissions
INSTITUTE OF MICROBIAL TECHNOLOGY (IMTECH)
(Council of Scientific & Industrial Research)
Sector 39-A, Chandigarh-160 036
Director, Institute of Microbial Technology, invites exceptionally motivated candidates who have passed M.Sc. and cleared CSIR/UGC NET, DBT JRF examination (A Category), or ICMR JRF examination (NOT THE NET LECTURESHIP OR THOSE SELECTED FOR WORKING IN ICMR PROJECTS ONLY) to appear for a walk-in interview on July 14, 2010, (Reporting Time 9.00 a.m. to 12 noon; kindly confirm your presence by e-mail at phd@imtech.res.in ) for pursuing doctoral research at IMTECH under the aegis of the Ph. D degree program being jointly run by IMTECH and the Jawaharlal Nehru University (JNU), New Delhi. For details please click here.
For other university and colleges admission dates and notification please click http://www.admissiondates.com/Tags/phd-admission
A Tribute to Manglore Aircrash Victims
It was very shocking news for me. May God help their family and make them strong enough.
Please click here to see more pictures.
Sunday, May 9, 2010
Neandertal genome yields evidence of interbreeding with humans
After years of looking, geneticists are shocked to find a link
Some people don’t just have a caveman mentality; they may actually carry a little relic of the Stone Age in their DNA.
A new study of the Neandertal genome shows that humans and Neandertals interbred. The discovery comes as a big surprise to researchers who have been searching for genetic evidence of human-Neandertal interbreeding for years and finding none.
About 1 percent to 4 percent of DNA in modern people from Europe and Asia was inherited from Neandertals, researchers report in the May 7 Science. “It’s a small, but very real proportion of our ancestry,” says study coauthor David Reich of the Broad Institute of MIT and Harvard in Cambridge, Mass. Comparisons of the human and Neandertal genomes are also revealing how humans evolved to become the sole living hominid species on the planet.
These three fragments of Neandertal bones yielded the first DNA evidence of human-Neandertal interbreeding.
“Neandertals are not totally extinct; they live on in some of us,” says Svante Pääbo of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, and leader of the Neandertal genome project.
He and other geneticists involved in the effort to compile the complete genetic instruction book of Neandertals didn’t expect to find that Neandertals had left a genetic legacy. Earlier analyses that looked at only a small part of the genome had contradicted the notion that humans and Neandertals intermixed (SN Online: 8/7/08).
“We as a consortium came into this with a very, very strong bias against gene flow,” Reich says. In fact, when he and his colleagues announced the completion of a rough draft of the Neandertal genome a year ago, the researchers said such genetic exchange was unlikely (SN: 3/14/09, p. 5).
But several independent lines of evidence now convince the researchers that humans and Neandertals did interbreed. “The breakthrough here is to show that it could happen and it did happen,” Pääbo says.
The result came as no surprise to some scientists, however. Archaeologists have described ancient skeletons from Europe that had characteristics of both early modern humans and Neandertals; evidence, the researchers say, of interbreeding between the two groups. But until the cataloging of the entire Neanderthal genome, genetic studies could find no evidence to support the idea.
“After all these years the geneticists are coming to the same conclusions that some of us in the field of archaeology and human paleontology have had for a long time,” says João Zilhão, an archaeologist and paleoanthropologist at the University of Bristol in England. “What can I say? If the geneticists come to this same conclusion, that’s to be expected.”
Researchers recreated the Neandertal’s genetic blueprints using DNA extracted from three bone fragments — each from a different Neandertal woman — found in a cave in Croatia.
Comparing the resulting blueprints of the female Neandertals, who lived about 40,000 years ago, with those of five present-day humans from China, France, Papua New Guinea and southern and western Africa, revealed that people outside of Africa carry Neandertal DNA.
Scientists were surprised to find that people from China and Papua New Guinea (places where Neandertals never lived) have just as much Neandertal ancestry as people from France. The group did not find traces of Neandertal heritage in the two African people studied. The result probably means that interbreeding between Neandertals and humans took place about 50,000 to 80,000 years ago in the Middle East as humans began migrating out of Africa to colonize the rest of the world, Reich says.
It is not clear how extensive interbreeding was; the data are consistent with either a short period with a great deal of interbreeding or with a long period of little interbreeding, says Richard E. (Ed) Green, a genome biologist now at the University of California Santa Cruz and a coauthor of the new study.
Comparison of the Neandertal genome to human and chimpanzee genetic sequences have led to some clues about recent human evolution. Neandertals “were not genetically very distinct from us,” says Pääbo. For example, the researchers were able to find only 78 proteins in which humans carry a different amino acid than is found in Neandertals and chimpanzees. That means that few changes in proteins have taken place in the past few hundred thousand years of human evolution. Researchers don’t know yet whether the changes in the proteins alter their function or give humans some survival advantage.
But some parts of the human genome clearly do produce an evolutionary advantage, the researchers say. Again, the team compared the human genome to those of Neandertals and chimpanzees and identified places where humans differ. If nothing of importance had happened in human evolution since humans and Neandertals diverged, such changes would be spread evenly across the genome, Green says. Instead, the researchers found large swaths of the genome where humans have distinct changes not found in Neandertals or chimpanzees. The team identified 212 such regions where “selective sweeps” were likely to have happened, many of which include genes involved in brain function. The researchers don’t yet know what the changes are or how they produce a selective advantage.
“These data are really a goldmine for understanding recent human evolution,” Green says.
Since humans and Neandertals could interbreed, some people question whether the two groups are different hominid species. The question doesn’t hold interest for John Hawks, an anthropologist at the University of Wisconsin–Madison. Genealogically, he says, the new study shows that many humans had a Neandertal great-great-great-great … grandfather. “It’s impossible to talk about them as ‘them’ anymore,” he says. “Neandertals are us.”
Source: Science News (May 6th 2010)
New Nerve Cells -- Even in Old Age
Yes, Researchers Find Different Types of Stem Cells in the Brains of Mature and Old Mice.
After birth the brain loses many nerve cells and this continues throughout life -- most neurons are formed before birth, after which many excess neurons degenerate. However, there are some cells that are still capable of division in old age -- in the brains of mice, at least. According to scientists from the Max Planck Institute of Immunobiology in Freiburg, different types of neuronal stem cells exist that can create new neurons. While they divide continuously and create new neurons in young animals, a large proportion of the cells in older animals persist in a state of dormancy. However, the production of new cells can be reactivated, for example, through physical activity or epileptic seizures. What happens in mice could also be applicable to humans as neurons that are capable of dividing also occur in the human brain into adulthood.
Different types of stem cells in the brain of mature mice. (Credit: Verdon Taylor (from: Lugert et al., Cell Stem Cell, May 7th, 2010))
The research is published in the journal Cell Stem Cell.
You can't teach an old dog new tricks. The corresponding view that the brain loses learning and memory capacity with advancing age prevailed for a long time. However, neuronal stem cells exist in the hippocampus -- a region of the brain that plays a central role in learning and memory functions -- that can produce new nerve cells throughout life. It is known from tests on mice that the newly formed cells are integrated into the existing networks and play an important role in the learning capacity of animals. Nonetheless, the formation of new cells declines with age and the reasons for this were unknown up to now.
Together with colleagues from Dresden and Munich, the Freiburg researchers have now succeeded in explaining for the first time why fewer new neurons are formed in the adult mouse brain. They managed to identify different populations of neuronal stem cells, thereby demonstrating that the hippocampus has active and dormant or inactive neuronal stem cells. "In young mice, the stem cells divide four times more frequently than in older animals. However, the number of cells in older animals is only slightly lower. Therefore, neuronal stem cells do not disappear with age but are kept in reserve," explains Verdon Taylor from the Max Planck Institute of Immunobiology.
The precise factors that influence the reactivation of dormant stem cells are not yet clear. The cells can, however, be stimulated to divide again. The scientists observed more newborn hippocampal neurons in physically active mice than in their inactive counterparts. "Consequently, running promotes the formation of new neurons," says Verdon Taylor. Pathological brain activity, for example that which occurs during epileptic seizures, also triggers the division of the neuronal stem cells.
Horizontal and radial stem cells
The different stem cell populations are easy to distinguish under the microscope. The first group comprises cells which lie perpendicular to the surface of the hippocampus. Most of these radial stem cells are dormant. As opposed to this, over 80% of the cells in the group of horizontal stem cells -- cells whose orientation runs parallel to the hippocampus surface -- continuously form new cells; the remaining 20% are dormant but sporadically become activated. The activity of genes such as Notch, RBP-J and Sox2 is common to all of the cells.
Radial and horizontal stem cells differ not only in their arrangement, apparently they also react to different stimuli. When the animals are physically active, some radial stem cells abandon their dormant state and begin to divide, while this has little influence on the horizontal stem cells. The result is that more radial stem cells divide in active mice. The horizontal stem cells, in contrast, are also influenced by epileptic seizures.
It would appear that neuronal stem cells are not only found in the brains of mice. The presence of neurons that are formed over the course of life has also been demonstrated in the human hippocamus. Therefore, scientists suspect that different types of active and inactive stem cells also arise in the human brain. It is possible that inactive stem cells in humans can also be activated in a similar way to inactive stem cells in mice. "There are indicators that the excessive formation of new neurons plays a role in epilepsy. The use of neuronal brain stem cells in the treatment of brain injuries or degenerative diseases like Alzheimers may also be possible one day," hopes Verdon Taylor.
Source: ScienceDaily (May 9, 2010)
Mother's Day
The history of Mother’s Day is centuries old and goes back to the times of ancient Greeks, who held festivities to honour Rhea, the mother of the Gods. The early Christians celebrated the Mother’s festival on the fourth Sunday of Lent to honour Mary, the mother of Christ.
Interestingly, later on, a religious order stretched the holiday to include all mothers, and named it the Mothering Sunday. The English colonists settled in America and discontinued the tradition of Mothering Sunday because of lack of time.
In 1872 Julia Ward Howe organised a day for mothers dedicated to peace. It is a landmark in the history of Mother’s Day.
In 1907, Anna M. Jarvis (1864-1948), a Philadelphia schoolteacher, began a movement to set up a national Mother’s Day in honour of her mother, Ann Maria Reeves Jarvis. She solicited the help of hundreds of legislators and prominent businessmen to create a special day to honour mothers.
The first Mother’s Day observance was a church service honouring Anna’s mother. Her hard work finally paid off in 1914, when President Woodrow Wilson proclaimed the second Sunday in May as a national holiday in honour of mothers.
Saturday, May 8, 2010
Monday, May 3, 2010
Housefull: Movie Review
Housefull is a romantic comedy about a man named Aarush, played by Akshay Kumar; he is the unluckiest man in the world when it comes to love.
Aarush believes his bad luck can vanish if he finds true love. In his quest for true love one lie leads to another and different people from different walks of life come together, adding even more confusion to this hilarious comedy of total chaos and mayhem.
As his co-star Deepika Padukone tells Akshay in the film: 'jis jhooth se kissi ka ghar basta ho, voh jhooth jhooth nahin hota.' Aarush ends up in these crazy situations because he has been hiding a deep secret; he actually has three wives! His first wife Sandy, played by Deepika Padukone, has always wanted to be in love, but thinks it only happens in fairy tales. His second wife Heetal, played by Lara Dutta, loves her husband so much that she feels as if she is living a fairy tale, while Devika, played by Jiah Khan, is a simple old-fashioned small-town girl.
No one knows about Aarush's secret except his best friend Bob, portrayed by Ritesh Deshmukh, who is as close as only a brother can be to Aarush. Aarush and Bob face a dilemma when Aarush's wives express that they want to move in with Aarush.
Aarush agrees to his wives' requests, but has to figure out a way to avoid that they find out what's going on, which is nearly impossible since they all live under one roof.
However, Sandy finds out and tells everything to her big brother Krishna, played by Arjun Rampal. Krishna goes to Aarush and finishes his whole game.
'Junk DNA' Drives Cancer Growth, Hodgkin's Lymphoma
Researchers from the University of Leeds, UK, the Charité University Medical School and the Max Delbrück Centre for Molecular Medicine (MDC) in Berlin, Germany, have discovered a new driving force behind cancer growth.
Their studies have identified how 'junk' DNA promotes the growth of cancer cells in patients with Hodgkin's lymphoma. Professor Constanze Bonifer (University of Leeds) and Dr Stephan Mathas (Charité, MDC) who co-led the study suspect that these pieces of 'junk' DNA, called 'long terminal repeats', can play a role in other forms of cancer as well. The work is published in Nature Medicine.
The researchers uncovered the process by which this 'junk DNA' is made active, promoting cancer growth.
"We have shown this is the case in Hodgkin's lymphoma, but the exact same mechanism could be involved in the development of other forms of blood cancer," said Prof. Bonifer. "This would have implications for diagnosis, prognosis, and therapy of these diseases."
'Long terminal repeats' (LTRs) are a form of 'junk DNA' -- genetic material that has accumulated in the human genome over millions of years. Although LTRs originate from viruses and are potentially harmful, they are usually made inactive when embryos are developing in the womb.
If this process of inactivation doesn't work, then the LTRs could activate cancer genes, a possibility that was suggested in previous animal studies. This latest research has now demonstrated for the first time that these 'rogue' active LTRs can drive the growth of cancer in humans.
The work focused on cancerous cells of Hodgkin's lymphoma (the Hodgkin-/Reed Sternberg cells) that originate from white blood cells (antibody-producing B cells). Unusually, this type of lymphoma cell does not contain a so-called 'growth factor receptor' that normally controls the growth of other B-cells.
They found that the lymphoma cells' growth was dependent on a receptor that normally regulates the growth of other immune cells, but it is not usually found in B-cells. However in this case, the Hodgkin-/Reed Sternberg cells 'hijacked' this receptor for their own purposes by activating some of the 'junk DNA'. In fact the lymphoma cells activated hundreds, if not thousands, of LTRs all over the genome, not just one.
Hodgkin-/Reed Sternberg cells may not be the only cells that use this method to subvert normal controls of cell growth. The researchers found evidence of the same LTRs activating the same growth receptor in anaplastic large cell lymphoma, another blood cancer.
The consequences of such widespread LTR activation are currently still unclear, according to the study's authors. Such processes could potentially activate other genes involved in tumour development. It could also affect the stability of chromosomes of lymphoma cells, a factor that may explain why Hodgkin-/Reed Sternberg cells gain many chromosomal abnormalities over time and become more and more malignant.
Sunday, May 2, 2010
Now, ‘cuddle hormone’ spray to make men more sensitive
Women’s prayers have finally been answered: Scientists have developed a spray which can make men sensitive and affectionate using a ''cuddle hormone''.
Forty eight healthy males participated in the experiment. Half received an oxytocin nose spray at the start of the experiment, the other half a placebo. The researchers then showed their test subjects photos of emotionally charged situations in the form of a crying child, a girl hugging her cat, and a grieving man. The test subjects were then invited to express the depth of feeling they experienced for the persons shown.
In summary, Dr. René Hurlemann of Bonn University ´ s Clinic for Psychiatry was able to state that "significantly higher emotional empathy levels were recorded for the oxytocin group than for the placebo group", despite the fact that the participants in the placebo group were perfectly able to provide rational interpretations of the facial expressions displayed. The administration of oxytocin simply had the effect of enhancing the ability to experience fellow-feeling. The males under test achieved levels which would normally only be expected in women. Under normal circumstances, the "weak" sex enjoys a clear advantage when it comes to the subject of "empathy".
In a second experiment, the participants had to use their computers to complete a simple observation test. Correct answers produced an approving face on the screen, wrong ones a disapproving one. Alternatively, the feedback appeared as green (correct) or red (false) circles. "In general, learning was better when the feedback was shown in the form of faces", states Dr. Keith Kendrick of the Cambridge Babraham Institute in England. "But, once again, the oxytocin group responded clearly better to the feedback in the form of facial expression than did the placebo group".
In this connection, the so-called amygdaloid nucleus appears to play an important role. This cerebral stucture, known generally to doctors as the amygdala, is involved in the emotional evaluation of situations. Certain people suffer from an extremely rare hereditary disease which progressively affects the amygdala. "We were lucky to be able to include two femals patients in our study group who were suffering this defect of the amygdala", says Hurlemann. "Both women reacted markedly worse to approving or disapproving faces in the observation test than did other women in a control group. Moreover, their emotional empathy was also affected". Hence, the researchers suspect that the amygdala could bear some form of co-responsibility for the effect of the oxytin.
One of the effects of the hormone oxytocin, also called as cuddle hormone, is that it triggers labour pains. It also strengthens the emotional bond between a mother and her new-born child. Oxytocin is released on a large scale during an orgasm, too. This neuropeptide is also associated with feelings such as love and trust. Our study has revealed for the first time that emotional empathy is modulated by oxytocin, and that this applies similarly to learning processes with social multipliers, says Hurlemann.
Source: Times of India
Forty eight healthy males participated in the experiment. Half received an oxytocin nose spray at the start of the experiment, the other half a placebo. The researchers then showed their test subjects photos of emotionally charged situations in the form of a crying child, a girl hugging her cat, and a grieving man. The test subjects were then invited to express the depth of feeling they experienced for the persons shown.
In summary, Dr. René Hurlemann of Bonn University ´ s Clinic for Psychiatry was able to state that "significantly higher emotional empathy levels were recorded for the oxytocin group than for the placebo group", despite the fact that the participants in the placebo group were perfectly able to provide rational interpretations of the facial expressions displayed. The administration of oxytocin simply had the effect of enhancing the ability to experience fellow-feeling. The males under test achieved levels which would normally only be expected in women. Under normal circumstances, the "weak" sex enjoys a clear advantage when it comes to the subject of "empathy".
In a second experiment, the participants had to use their computers to complete a simple observation test. Correct answers produced an approving face on the screen, wrong ones a disapproving one. Alternatively, the feedback appeared as green (correct) or red (false) circles. "In general, learning was better when the feedback was shown in the form of faces", states Dr. Keith Kendrick of the Cambridge Babraham Institute in England. "But, once again, the oxytocin group responded clearly better to the feedback in the form of facial expression than did the placebo group".
In this connection, the so-called amygdaloid nucleus appears to play an important role. This cerebral stucture, known generally to doctors as the amygdala, is involved in the emotional evaluation of situations. Certain people suffer from an extremely rare hereditary disease which progressively affects the amygdala. "We were lucky to be able to include two femals patients in our study group who were suffering this defect of the amygdala", says Hurlemann. "Both women reacted markedly worse to approving or disapproving faces in the observation test than did other women in a control group. Moreover, their emotional empathy was also affected". Hence, the researchers suspect that the amygdala could bear some form of co-responsibility for the effect of the oxytin.
One of the effects of the hormone oxytocin, also called as cuddle hormone, is that it triggers labour pains. It also strengthens the emotional bond between a mother and her new-born child. Oxytocin is released on a large scale during an orgasm, too. This neuropeptide is also associated with feelings such as love and trust. Our study has revealed for the first time that emotional empathy is modulated by oxytocin, and that this applies similarly to learning processes with social multipliers, says Hurlemann.
Source: Times of India
Insects that make own nutrients found
Scientists claim to have identified for the first time an insect, known as aphids, that can make their own essential nutrients called carotenoids.
No other animals are known to make the potent antioxidants. Until now researchers thought that the only way animals could obtain the orangey-red compounds was from their diet. But, an Arizona University team has found otherwise.
In their research, the scientists have also figured out how the aphids they studied, known as pea aphids, acquired the ability to make carotenoids which are building blocks for molecules crucial for vision, healthy skin, bone growth and other key physiological functions.
"What happened is a fungal gene got into an aphid and was copied. Although gene transfers between microorganisms are common, finding a functional fungus gene as part of an animal's DNA is a first.
"Animals have a lot of requirements that reflect ancestral gene loss. This is why we require so many amino acids and vitamins in the diet.
"Until now it has been thought that there is simply no way to regain these lost capabilities. But this case in aphids shows that it is indeed possible to acquire the capacity to make needed compounds.
"Possibly this will be an extraordinarily rare case. But so far in genomic studies, a single initial case usually turns out to be only an example of something more widespread," Nancy Moran, who led the team, said.
In fact, an accident in the laboratory plus the recent sequencing of the pea aphid genome made their latest discovery possible, the scientists say.
Pea aphids, known to scientists as Acyrthosiphon pisum, are either red or green. Aphids are clonal -- the mothers give birth to daughters that are genetically identical to their mothers.
So when an aphid in the lab's red 5A strain began giving birth to yellowish-green babies, the scientists knew they were looking at the results of a mutation.
"We named it 5AY for yellowish. That yellowish mutant happened in 2007. We just kept the strain as a sort of pet in the lab. I figured that one day we'd figure out how that happened," she said.
Symbiotic bacteria live within aphids in specialised cells. The bacteria, which are passed from mother to babies, supply the insects with crucial nutrition. If their bacteria die, the aphids die.
The scientists, who have been studying the pea aphid-bacteria system for decades, already knew the three main species of symbiotic bacteria did not make carotenoids. They also were pretty sure the aphids didn't get their carotenoids from their diet.
Aphids eat by sucking the phloem sap from plants, but the sap is carotenoid-poor. In addition, the carotenoids in the aphids were different from those usually found in plants, the scientists say.
No other animals are known to make the potent antioxidants. Until now researchers thought that the only way animals could obtain the orangey-red compounds was from their diet. But, an Arizona University team has found otherwise.
In their research, the scientists have also figured out how the aphids they studied, known as pea aphids, acquired the ability to make carotenoids which are building blocks for molecules crucial for vision, healthy skin, bone growth and other key physiological functions.
"What happened is a fungal gene got into an aphid and was copied. Although gene transfers between microorganisms are common, finding a functional fungus gene as part of an animal's DNA is a first.
"Animals have a lot of requirements that reflect ancestral gene loss. This is why we require so many amino acids and vitamins in the diet.
"Until now it has been thought that there is simply no way to regain these lost capabilities. But this case in aphids shows that it is indeed possible to acquire the capacity to make needed compounds.
"Possibly this will be an extraordinarily rare case. But so far in genomic studies, a single initial case usually turns out to be only an example of something more widespread," Nancy Moran, who led the team, said.
In fact, an accident in the laboratory plus the recent sequencing of the pea aphid genome made their latest discovery possible, the scientists say.
Pea aphids, known to scientists as Acyrthosiphon pisum, are either red or green. Aphids are clonal -- the mothers give birth to daughters that are genetically identical to their mothers.
So when an aphid in the lab's red 5A strain began giving birth to yellowish-green babies, the scientists knew they were looking at the results of a mutation.
"We named it 5AY for yellowish. That yellowish mutant happened in 2007. We just kept the strain as a sort of pet in the lab. I figured that one day we'd figure out how that happened," she said.
Symbiotic bacteria live within aphids in specialised cells. The bacteria, which are passed from mother to babies, supply the insects with crucial nutrition. If their bacteria die, the aphids die.
The scientists, who have been studying the pea aphid-bacteria system for decades, already knew the three main species of symbiotic bacteria did not make carotenoids. They also were pretty sure the aphids didn't get their carotenoids from their diet.
Aphids eat by sucking the phloem sap from plants, but the sap is carotenoid-poor. In addition, the carotenoids in the aphids were different from those usually found in plants, the scientists say.
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