Fossil sirenians give scientists new look at ancient climate

What tales they tell of their former lives, these old bones of sirenians, relatives of today's dugongs and manatees. And now, geologists have found, they tell of the waters in which they swam.

While researching the evolutionary ecology of ancient sirenians--commonly known as sea cows--scientist Mark Clementz and colleagues unexpectedly stumbled across data that could change the view of climate during the Eocene Epoch, some 50 million years ago.

Clementz, from the University of Wyoming, published the results in a paper in this week's issue of the journal Science.

He and co-author Jacob Sewall of Kutztown University in Pennsylvania used their findings to dispute a popular scientific assumption about the temperature and composition of seawater during the time marked by the emergence of the first modern mammals.

The Sirenia, named for the sirens or mermaids of Greek myth, is an order of aquatic, plant-eating mammals that live in swamps, rivers, estuaries, marine wetlands and coastal waters.

Four species of "sea cows" are alive today, in two families and genera: the dugong, with one species, and manatees with three species.

Sirenia also includes the Steller's sea cow, extinct since the 18th century, and others known only from fossil remains. The order evolved during the Eocene more than 50 million years ago.

In their paper--"Latitudinal Gradients in Greenhouse Seawater δ18O: Evidence from Eocene Sirenian Tooth Enamel"--the scientists used the isotopic composition of sirenian fossils from a broad time period and geographic area, along with climate simulation data, to add to the long-running debate over Eocene climate.

"This study demonstrates the value of the fossil record, and of examining the deep time record of paleoclimatological events, so we can better understand climate change today," says Lisa Boush, program director in the National Science Foundation (NSF)'s Division of Earth Sciences, which funded the research.

"This novel approach will potentially transform our way of thinking about the hydrologic response to global climate change."

"I wasn't looking at it from this direction when we started the project," says Clementz, whose research is part of an NSF CAREER award.

"But once we started accumulating enough samples, we could step back and get a better understanding of the habitat and dietary preferences of these fossil species, and also of the big picture. We saw that it could be reflecting climate and environmental change."

A new look at climate during the Eocene, when Earth underwent a dramatic change, could help scientists better understand global climate change today.

Most scientists assumed that the oxygen isotopic composition of seawater in the past was very similar to that of today, with high values at low latitudes and low values at high latitudes.

Isotopes are variants of atoms of a particular chemical element, in this case oxygen, with differing numbers of neutrons.

"But when we looked at the oxygen isotopic values of the fossils from low-latitude sites for the Eocene, they were much lower than we would predict," says Clementz.

The finding suggests that low-latitude sites during the Eocene were much wetter than today.

"This created a very different distribution in the oxygen isotopic composition of seawater for this time interval, which would, in turn, significantly impact estimates of paleoclimate and paleotemperature in the distant past," says Clementz.

"Scientists have used this assumption of the oxygen isotopic values of seawater to constrain temperature estimates for the past."

In their paper, Clementz and Sewall show that the assumption may be flawed, which could mean that previous estimates of water temperature are incorrect.

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Starting a new metabolic path

Efforts to engineer new metabolic pathways into microbes for the inexpensive production of valuable chemical products, such as biofuels or therapeutic drugs, should get a significant boost in a new development from the U.S. Department of Energy (DOE)'s Joint BioEnergy Institute (JBEI). Researchers there have successfully demonstrated a technique they call "targeted proteomics" that speeds up and improves the ability to identify and quantify specific proteins within a cell or microorganism. "Metabolic engineers and synthetic biologists can use our directed proteomic technique to get useful information about protein levels in their organisms, which in turn can be used to direct valuable followup experiments," says Christopher Petzold, chemist and deputy director for proteomics at JBEI, who led this research. "We believe that targeted proteomics is a useful tool that fills a much needed gap in efforts to engineer new metabolic pathways for microbes."

Petzold, who also holds an appointment with the Lawrence Berkeley National Laboratory (Berkeley Lab)'s Physical Biosciences Division, is the corresponding author on a paper describing this research that was published in the journal Metabolic Engineering. The paper is titled "Targeted proteomics for metabolic pathway optimization: Application to terpene production." Coauthoring the paper with Petzold were Alyssa Redding-Johanson, Tanveer Batth, Rossana Chan, Rachel Krupa, Heather Szmidt, Paul Adams, Jay Keasling, Taek Soon Lee and Aindrila Mukhopadhyay.

Metabolic engineering is the practice of altering genes and chemical pathways within a cell or microorganism to increase production of a specific chemical substance. It is fast becoming one of the principal techniques of modern biotechnology for the microbial production of chemicals that are currently derived from non-renewable resources or from natural resources that are limited. Critical to the success of metabolic engineering efforts are techniques that enable researchers to assemble and optimize novel metabolic pathways in microbes. Given that such pathways often involve multiple different factors, performance- hampering problems, such as the abundance of proteins and messenger RNA, or the activity of enzymes, are not always evident simply by measuring the amount of final product obtained.

"Synthetic biologists and metabolic engineers will utilize a variety of analytical methods to identify the parts of a metabolic pathway that limit production," Petzold says. "At the metabolite level, for example, monitoring all pathway intermediates helps identify bottlenecks where further engineering could improve the final product titer. However, pathways that divert intermediates to native processes at the cost of final product formation may disguise the actual location of a bottleneck."

Researchers have tried developing assays to evaluate every intermediate in a given metabolic pathway but this has been a major challenge because intermediates often degrade rapidly or are isomers, and because there are few available standards for such evaluations.

"Engineers are often left to guess at the metabolite levels in parts of the pathway," Petzold says.

Targeted proteomics is based on a variation of mass spectrometry called selected-reaction monitoring (SRM) that can be used to rapidly detect and quantify multiple target proteins within complex protein mixtures, such as those found in cells or microbes. When coupled to liquid chro¬matography (LC),SRM mass spectrometry analysis provides high selectivity and sensitivity through the elimination of background signal and noise even in the most complex mix of proteins. This is made possible by selecting only two points of mass for monitoring - a peptide mass and a specific fragment mass – rather than scanning the entire mass range.

"Carrying out targeted proteomics through SRM mass spectrometry analysis is most useful when quantification of multiple proteins in a single sample is desired," Petzold says. "Working with protein-specific peptides, you can analyze 20 or more targeted proteins in an hour, and entire engineered metabolic pathways can be quantified in a single experiment, something that isn't practical with conventional immunoblot analysis."

Petzold and his co-authors demonstrated the effectiveness of their targeted proteomics technique when they used it to measure protein levels in Escherichia coli that were engineered with yeast proteins to produce amorpha-4,11-diene, a member of the family of plant chemicals known as sesquiterpenes. Strains of E. coli containing a high flux mevalonate pathway have the potential to provide a vast range of high value sesquiterpenes and other isoprenoid-based chemical compounds, which today are typically obtained from petrochemical or plant sources.

"Our analysis identified two mevalonate pathway proteins, mevalonate kinase and phosphomevalonate kinase, both from yeast, as potential bottlenecks," Petzold says. "Codon-optimization of the genes encoding mevalonate kinase and phosphomevalonate kinase, and expression from a stronger promoter led to significantly improved levels of these two proteins and a more than three-fold improvement in the final amorpha-4,11-diene titer, greater than 500 milligrams per liter."

Petzold and his JBEI colleagues are now in the process of implementing "scheduled-SRM," a variation of the SRM mass spectrometry analysis that would allow them to easily detect and quantify 100 proteins in a single experiment that can be completed in less than two hours.

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Standing up for athletes at risk

When a high school athlete drops dead, the rare but fatal condition called "sudden death syndrome" dominates the headlines. For reasons that remain a mystery to scientists, some young athletes — especially young males — begin to experience an unusual heart arrhythmia. With over-exertion, their hearts stop pumping, leading to sudden death. Until now, screening for the hard-to-detect syndrome has been prohibitively expensive. But cardiologist Dr. Sami Viskin of Tel Aviv University's Sackler Faculty of Medicine has developed a new test that's already being used by doctors in America –– and may have already saved lives.

The "Viskin Test" is based on the researcher's discovery that almost imperceptible abnormalities between normal and at-risk patients could be suddenly be made more visible using a simple bedside test that requires a subject to suddenly stand up. When standing, at-risk patients will experience a measurable difference in a portion of their heart rate called the QT interval. The difference can be detected by an electrocardiogram (ECG).

Dr. Viskin described his research in a recent issue of the Journal of the American College of Cardiology.

The long and short of the QT test

"Current screening methods offer no real therapeutic value, because very few people who experience arrhythmias, up to 20 percent of the population, will ever die from sudden death," Dr. Viskin says. "Moreover, there is such a significant overlap between what's normal and abnormal on an ECG that we need additional screening parameters. This test, when done on people with strong symptoms, can really give us doctors a yardstick to compare those at risk for sudden death syndrome to those who would otherwise go on to live a healthy life."

According to Dr. Viskin, the QT interval shortens when the heart rate accelerates, but this response is not instantaneous. In the study, he tested whether sudden changes in a body as it stands up would reveal an abnormally prolonged QT interval patients with long QT syndrome (LQTS), the most common cause of sudden death. Those affected with LQTS have a normal heart structure but have problems in the electrical discharge in the heart — they have trouble "recharging" after these sudden changes.

Young people who suddenly faint for no reason, have dizzy spells or have a family history of LQTS are very good potential candidates for this new test, Dr. Viskin says.

A warning for immediate intervention

In the study that led to the "Viskin Test," Dr. Viskin assessed 68 patients with LQTS and 82 control subjects who all underwent a baseline ECG while resting in the supine position. They were then asked to get up quickly and stand still during continuous ECG recording. The QT interval was then studied over various time periods.

In response to brisk standing, both the LQTS patients and the control subjects showed similar heart rate acceleration. But Dr. Viskin discovered that the QT interval in LQTS patients increased significantly.

"This test adds diagnostic value. And the beauty of the test," Dr. Viskin adds, "is that it's easily done at the patient's bedside. It eliminates the need for more expensive IV tests and more strenuous exercise tests."

He adds that, while untreated LQTS can be life-threatening, the therapies to treat it can be very effective.

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Small doses of cancer treatment information 'more effective'

When information about cancer treatment options is given in small doses, the patient is more likely to make a sensible decision, research has suggested.

A study from the University of Michigan investigated the cancer treatment choices of women with breast cancer, and found that those who were presented with the information in small doses, rather than all at once, made smarter choices.

Brian Zikmund-Fisher said: "What that tells me is that it doesn't take very much information to be too much, especially with patients who have trouble with numbers.

"When we try to provide patients with full and complete information, we often end up overwhelming them."

In other news, the minimization of chemoradiation side effects could improve the survival of brain cancer patients, according to a study published in the British Journal of Cancer.

Glioma patients who did not have early side effects of the treatment were seen to live an average of four months longer than those who did.

Health news

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Time to spring clean... your mind? Scientists say memory lapses can be blamed on too much irrelevant information

If you struggle to remember names and numbers or frequently fail to follow the plot of a film, help could be at hand.

Scientists say the problem is that you know too much – and you need to declutter, or spring-clean your mind.

Experiments show that the memory lapses that come with age are not simply due to brain slowing down.

Instead, they can be blamed on the well-used brain finding it more and more difficult to stop irrelevant information interfering with the task in hand.

The first step in the study was to compare the working memory of the young and old. Working memory involves holding information in mind while manipulating it mentally.

Examples in everyday life include retain plots of films and books to understand or predict what will happen next and following the thread of a conversation while working out how you can contribute to the topic.

In the context of the study, it involved giving the volunteers groups of sentences and asking them to work out whether each line made sense – and to remember the last word of each sentence.

Overall, the younger people, who had an average age of 23, did better, the Quarterly Journal of Experimental Psychology reports.

The Canadian researchers then did a second experiment to see what was hindering  the older volunteers, who had an average age of 67.

This involved being shown a pictures of eight animals and being asked to memorise the order in which the creatures appeared.

The volunteers were then shown dozens of the pictures and asked to click on their computer mouse when the first animal in their memorised sequence occurred, then the second and so on.

The older adults found it more difficult to progress, suggesting the previous picture was stuck in their mind.

Mervin Blair, of Montreal’s Concordia University, said: ‘We found that  the older adults had more difficulty in getting rid of previous information.

‘We found that that accounted for a lot of the working memory problems seen in  the study.’

A third study confirmed that the memory problems were not simply due to a  simple slowing down of the mind.

Mr Blair, a PhD candidate, says that the older mind appears to have trouble  suppressing irrelevant information. This makes it more difficult to concentrate on the here and now.

For those who have trouble remembering, he suggests relaxation exercises to  declutter the mind.

‘Reduce clutter, if you don't, you may not get anything done.’

Keeping the mind young, through learning a language or musical instrument can also help.

He added that younger people can also fall foul of memory lapses caused by a failure to suppress extraneous information, with sleepless nights making it  harder for the brain to function properly.

Previous research has found that the part of the brain that keeps embarrassing  thoughts in check also weakens with age, leading to people losing some of their  inhibitions.

In other words, outspoken old people aren't being rude - they just can't hold  their tongues.

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Iron rich salt to fight malnutrition

With high prevalence of anaemia in the country, the government has decided to promote iron fortified iodised salt as a measure to deal with malnutrition.

The decision was taken at a meeting held in the Prime Minister's Office on promoting consumption of iron fortified iodised salt.

The meeting attended by various ministries called for the urgent measures to tackle anaemia in India's population, particularly among adolescent girls, women and children.

Anaemia is caused by inadequate intake and poor absorption of iron. It can be prevented and cured by promoting consumption of iron rich foods and iron supplements.

The National Institute of Nutrition (NIN), Hyderabad, has developed technologies for the double fortification of salt with iodine and iron.

Health news

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Breaking – Ford Focus sedan caught on test in Chennai

Two Indian Autos Blog readers have reported sightings of the Ford Focus testing near the Saidapet area in Chennai. The vehicle had one person on board and was driven quickly.

It featured multi-spoke alloys, black interiors and silver body paint (roughly like what you see above). The badges were covered using black duct tape.

Both readers could not get pictures as the in one case the vehicle zoomed past in the opposite direction and the person wasn’t carrying a camera in the other. Having said this, it is only a matter of time before eagle-eyed petrolheads get hold of snaps that confirm this development.

During the unveiling of the new Fiesta at a mall in Delhi last week, top Ford officials opened up on the possibility of the Focus arriving to India. They said the C-Platform, which the Focus is based on, is heading to India along with the CD-Platform, which the Mondeo uses. Exciting times are ahead in Focus’ segment as Hyundai is planning the Avante and Honda is all set to launch the new Civic here as well.

Technology news

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