Scientists Visualize How Cancer Chromosome Abnormalities Form in Living Cells

 

For the first time, scientists have directly observed events that lead to the formation of a chromosome abnormality that is often found in cancer cells. The abnormality, called a translocation, occurs when part of a chromosome breaks off and becomes attached to another chromosome. The results of this study, conducted by scientists at the National Cancer Institute (NCI), part of the National Institutes of Health, appeared Aug. 9, 2013, in the journal Science.

Chromosomes are thread-like structures inside cells that carry genes and function in heredity. Human chromosomes each contain a single piece of DNA, with the genes arranged in a linear fashion along its length.

Chromosome translocations have been found in almost all cancer cells, and it has long been known that translocations can play a role in cancer development. However, despite many years of research, just exactly how translocations form in a cell has remained a mystery. To better understand this process, the researchers created an experimental system in which they induced, in a controlled fashion, breaks in the DNA of different chromosomes in living cells. Using sophisticated imaging technology, they were then able to watch as the broken ends of the chromosomes were reattached correctly or incorrectly inside the cells.

Translocations are very rare events, and the scientists' ability to visualize their occurrence in real time was made possible by recently available technology at NCI that enables investigators to observe changes in thousands of cells over long time periods. "Our ability to see this fundamental process in cancer formation was possible only because of access to revolutionary imaging technology," said the study's senior author, Tom Misteli, Ph.D., Laboratory of Receptor Biology and Gene Expression, Center for Cancer Research, NCI.

 

The scientists involved with this study were able to demonstrate that translocations can occur within hours of DNA breaks and that their formation is independent of when the breaks happen during the cell division cycle. Cells have built-in repair mechanisms that can fix most DNA breaks, but translocations occasionally occur.

To explore the role of DNA repair in translocation formation, the researchers inhibited key components of the DNA damage response machinery within cells and monitored the effects on the repair of DNA breaks and translocation formation. They found that inhibition of one component of DNA damage response machinery, a protein called DNAPK-kinase, increased the occurrence of translocations almost 10-fold. The scientists also determined that translocations formed preferentially between pre-positioned genes.

"These observations have allowed us to formulate a time and space framework for elucidating the mechanisms involved in the formation of chromosome translocations," said Vassilis Roukos, Ph.D., NCI, and lead scientist of the study.

"We can now finally begin to really probe how these fundamental features of cancer cells form," Misteli added.

This research was supported by the Intramural Research Program of the NCI's Center for Cancer Research.

Source: Science Daily

R.Sawas

Global Warming Has Increased Monthly Heat Records Worldwide by a Factor of Five, Study Finds

 

 

 

Monthly temperature extremes have become much more frequent, as measurements from around the world indicate. On average, there are now five times as many record-breaking hot months worldwide than could be expected without long-term global warming, shows a study now published in Climatic Change. In parts of Europe, Africa and southern Asia the number of monthly records has increased even by a factor of ten. 80 percent of observed monthly records would not have occurred without human influence on climate, concludes the authors-team of the Potsdam Institute for Climate Impact Research (PIK) and the Complutense University of Madrid.

"The last decade brought unprecedented heat waves; for instance in the US in 2012, in Russia in 2010, in Australia in 2009, and in Europe in 2003," lead-author Dim Coumou says. "Heat extremes are causing many deaths, major forest fires, and harvest losses – societies and ecosystems are not adapted to ever new record-breaking temperatures." The new study relies on 131 years of monthly temperature data for more than 12,000 grid points around the world, provided by NASA. Comprehensive analysis reveals the increase in records.

The researchers developed a robust statistical model that explains the surge in the number of records to be a consequence of the long-term global warming trend. That surge has been particularly steep over the last 40 years, due to a steep global-warming trend over this period. Superimposed on this long-term rise, the data show the effect of natural variability, with especially high numbers of heat records during years with El Niño events. This natural variability, however, does not explain the overall development of record events, found the researchers.

Natural variability does not explain the overall development of record events

If global warming continues, the study projects that the number of new monthly records will be 12 times as high in 30 years as it would be without climate change. "Now this doesn't mean there will be 12 times more hot summers in Europe than today – it actually is worse," Coumou points out. For the new records set in the 2040s will not just be hot by today's standards. "To count as new records, they actually have to beat heat records set in the 2020s and 2030s, which will already be hotter than anything we have experienced to date," explains Coumou. "And this is just the global average – in some continental regions, the increase in new records will be even greater."

"Statistics alone cannot tell us what the cause of any single heat wave is, but they show a large and systematic increase in the number of heat records due to global warming," says Stefan Rahmstorf, a co-author of the study and co-chair of PIK's research domain Earth System Analysis. "Today, this increase is already so large that by far most monthly heat records are due to climate change. The science is clear that only a small fraction would have occurred naturally.

N.H.Khider

Source: Science Daily

 

 

 

Sea Level Rise Of One Meter Within 100 Years

New research indicates that the ocean could rise in the next 100 years to a meter higher than the current sea level – which is three times higher than predictions from the UN's Intergovernmental Panel on Climate Change, IPCC.

The groundbreaking new results from an international collaboration between researchers from the Niels Bohr Institute at the University of Copenhagen, England and Finland are published in the scientific journal Climate Dynamics.

According to the UN's Intergovernmental Panel on Climate Change the global climate in the coming century will be 2-4 degrees warmer than today, but the ocean is much slower to warm up than the air and the large ice sheets on Greenland and Antarctica are also slower to melt. The great uncertainty in the calculation of the future rise in the sea level lies in the uncertainty over how quickly the ice sheets on land will melt and flow out to sea. The model predictions of the melting of the ice sheets are the basis for the Intergovernmental Panel on Climate Change's predictions for the rise in sea level are not capable of showing the rapid changes observed in recent years. The new research has therefore taken a different approach.

Looking at the direct correlation

"Instead of making calculations based on what one believes will happen with the melting of the ice sheets we have made calculations based on what has actually happened in the past. We have looked at the direct relationship between the global temperature and the sea level 2000 years into the past", explains Aslak Grinsted, who is a geophysicist at the Centre for Ice and Climate at the Niels Bohr Institute at the University of Copenhagen.

With the help of annual growth rings of trees and analysis from ice core borings researchers have been able to calculate the temperature for the global climate 2000 years back in time. For around 300 years the sea level has been closely observed in several places around the world and in addition to that there is historical knowledge of the sea level of the past in different places in the world.

By linking the two sets of information together Aslak Grinsted could see the relationship between temperature and sea level. For example, in the Middle Ages around 12th century there was a warm period where the sea level was approximately 20 cm higher than today and in the 18th century there was the 'little ice age', where the sea level was approximately 25 cm lower than it is today.

A rise in sea level in the future as in the past

Assuming that the climate in the coming century will be three degrees warmer, the new model predictions indicate that the ocean will rise between 0,9 and 1,3 meters. To rise so much so quickly means that the ice sheets will melt much faster than previously believed. But it has already been observed that the ice sheets react quicker to increases in temperature than experts thought just a few years ago. And studies from the ice age show that ice sheets can melt quickly. When the ice age ended 11.700 years ago, the ice sheets melted so quickly that sea level rose 11 millimeters per year – equivalent to a meter in 100 years. In the current situation with global warming, Aslak Grinsted believes, that the sea level will rise with the same speed – that is to say a meter in the span of the next 100 years

Source: Science Daily

 N.H.Khider

Facebook Employees ‘Accessed User Passwords’

Katherine Losse, ex-speech writer for Mark Zuckerberg, is now warning the masses of open password access. She is claiming that the social network giant has a master password, allowing entry to any account on the popular platform, according to the Voice of Russia.

She explained to the media that staff needed to have access to accounts in order to manage and repair user issues, claiming that it was common practice at the time for early-stage startups to give their staff access to customers’ personal information. This may raise concerns as an unknown amount of Facebook users login with that very password on other networks too.

Still, Losse did confess that more sophisticated ways of logging in to fix accounts has been put in place and Facebook now has “very, very strict processes” enabled to keep passwords and user information safe and sound.

“Facebook is very highly regulated and places great importance on the integrity of the information people choose to add to it,” a source close to Facebook said.

Two kinds of staff members are allowed to enter a user’s account, the ones from the operations team and the security team. Even though these employees get access to a person’s private account, this is monitored and logged every day.

The Irish Data Protection Commission discovered through an audit that Facebook actually has “an appropriate framework to ensure that all access to user data is on a need to know basis”.

Still, privacy campaign Big Brother Watch claims that this incident is another reminder for internet users to always ask themselves who can dip into their virtual communications.

"Whether it’s an administrator doing it themselves, or as we’ve seen with other services people resetting the administrator’s password and accessing it themselves, with any service like this there is always a risk of your privacy being compromised. The key difference with Facebook is that it is so much faster to identify the account of the person you’re trying to snoop on,” Nick Pickles, director of privacy campaign Big Brother Watch, said.

 “Ultimately whether it’s health records or Facebook accounts, someone other than you is always going to need to have the ability to access your data, whether for security or service delivery reasons. The question people should be asking is just how much personal information you’re willing to be available in the first place,” Pickles said.

Back in 2009, a hacker from France got a hold of a Twitter staff account, giving him clearance to look at user accounts on the site. After he guessed the answer for the secret question to obtain their Yahoo password, the hacker said he got the chance to grab information about the staffer’s Twitter login data.

H.M 

Atlantic Ocean may disappear soon

According to some scientists, the Atlantic Ocean is rapidly "aging" and may soon disappear from the face of the Earth. A team of researchers from Australia found a quickly forming subduction zone on the ocean floor. Usually these zones are a sign of "aging." Scientists do not rule out that their formation is to be blamed on the Mediterranean Sea that has been "dying" for a long time.

For many of us the oceans are symbols of eternity and immutability, but in fact they are not. Even the largest bodies of water on our planet do not last forever - they appear, develop, grow old, and then disappear. For example, look at the Tethys Ocean that existed between the ancient continents of Laurasia and Gondwana during the Late Paleozoic and Mesozoic era (320 to 66.5 million years ago). What is left of this mighty river basin? Only a few small seas - the Mediterranean, Black, and Caspian Seas and modest Persian Gulf.

Usually new oceans are born when continents break apart and hot magma pours into the faults, hardens and turns into the oceanic crust. This is how the Atlantic Ocean was created in the Mesozoic era when the supercontinent Pangaea split into southern Gondwana and northern Laurasia continents. Conversely, old oceans dye when continents collide, and the oceanic crust under their pressure sinks back into the mantle. The abovementioned Tethys disappeared when Africa and India approached Eurasia, not leaving any room for the water basin before separating these continents.

Obviously, even the oceans are subject to aging. Some of them are aging much faster than scientists assume. Recently, an Australian scientist Joao Duarte of Monash University and his colleagues found that the Atlantic Ocean does not have much left to live. This seems rather surprising because, according to the conventional opinion, this body of water is rather young. This is evidenced by the bottom of the subduction zones - linear stretches along which some blocks of the earth's crust dip under the others. In these areas the old crust goes into the mantle, giving place to a younger mantel. The younger mantle leaves the ground during spreading - a process of an impulsive and multiple shifts of the lithosphere of the oceanic crust and filling the freed space with magma generated in the mantle.

Interestingly, spreading zones exist in the Atlantic Ocean. This process takes place in the Mid-Atlantic Ridge, and is quite active. But this indicates the young age of the ocean. In the Pacific there are many subduction zones, but quite a few places where spreading occurs, therefore it is considered old enough. However, as it turned out, the Atlantic Ocean is not that young if it has subduction zones.

Dr. Duarte's research group was concerned with the fact that in 1755 and 1969 Portugal was rocked by powerful earthquakes whose epicenters were in the depths of the ocean. This suggests that something unusual was happening in the deep waters, for example, formation of subduction zones. Over the years the oceanic crust cools down and becomes denser, so at some point it can spontaneously become deformed, that is, bend and subside back into the mantle. Such "movements" of the crust often generate earthquakes with a deep epicenter.

 

In addition, it was known that there is a great deal of overt Hurst faults in the part of the Atlantic close to Gibraltar. They are small areas of the crust where some fragments overlap other rocks. Typically, these sites are markers of the beginning of a subduction zone formation. For eight years Duarte's team was engaged in mapping the geological activity at the Portuguese coast, and as a result, scientists have found that these over thrust faults were linked to each other with transform faults - areas where the rocks rub against each other at the same level. This creates a large fault system stretching over several hundred kilometers, which, apparently, is none other than an emerging subduction zone.

But why did this zone appear in a quiet in terms of tectonic activity area? Dr. Duarte believes that the "dying" Mediterranean Sea is to blame for its emergence. In fact, the investigated location is a mere 400 km to the west of the Gibraltar Arc - a subduction zone in the west of this body of water. In addition, the researchers found that the discovered transform faults connect the Gibraltar Arc with a new subduction zone. Most likely, the remnants of the Tethys Ocean, interacting with the Atlantic crust, caused premature aging of the second largest ocean on Earth.

"We can say with some confidence that we have an example of an infection by subduction. The Mediterranean Sea, in turn, could have "caught" subduction from an ancient ocean, and so on until the beginning of time. As you can see, this process is similar to a contagious disease.

But if this is the case, then perhaps we have witnessed a turning point in the history of the Atlantic. These areas will produce cracks that sooner or later will lead to a fault in the lithospheric plate. This may cause a shift of continents and, therefore, degradation of the Ocean," Joao Duarte commented on the study. According to his calculations, the premature death of the Atlantic can happen in 220 million years, and Europe and America will unite and the entire ocean will disappear from the face of the Earth.

Duarte's group theory was well received by many scientists, but not everyone agrees with his "apocalyptic" outlook. This "infectious theory" can explain the formation of subduction zones. However, according to a geologist Jacques Deversher of Brest University (France), it is too early to say with confidence that in this part of the world a new area will open, and more research is needed. Duarte's group was not going to stop their research, and now scientists are looking for a confirmation of the hypothesis in other parts of the Atlantic Ocean.

Source:Pravda.Ru

R.S

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