Chemistry – Page 34 – David Bradley

Obesity Gene

Obesity overweight Today’s claims in the media about the recently discovered obesity gene are at best overwrought and at worst downright dangerous. A vast study involving more than twenty research centres across the UK has allegedly demonstrated that almost one fifth of us carry a variant of the gene known as FTO that predisposes us to obesity or overweight.

According to the researchers, “Obesity is a serious international health problem that increases the risk of several common diseases.” Fair comment. They add that, “The genetic factors predisposing to obesity are poorly understood.” Another fair comment.

They then report that while carrying out a genome-wide search for type 2 diabetes susceptibility genes among 13 groups of almost 40000 participants they have identified a common variant in the FTO gene that predisposes to diabetes through an effect on body mass index (BMI).

Additionally, the team reports that there is a cumulative, or additive, association of the variant with BMI. They found that 16% of the adults with the risky genetics weighed about 3 kilograms more than the others and were almost twice as likely to be obese, when compared to people without the risk allele. Moreover, the team says that they observe this genetic risk factor in individuals age 7 years and older and say that it reflects a specific increase in fat mass.

But, all this talk of obesity being down to genes will provide many individuals with an excuse along the lines of “it’s my glands”, which has become something of a serious cliche for some people who simply refuse to reduce the calorie intake and to add serious amounts of exercise to their daily routine.

The politics of obesity aside, I contacted metabolic expert Jeremy Nicholson of Imperial College London who recently discovered that calorie restriction in dogs extends life, reduces the risk of diabetes and metabolic disorders, and could be due to a change in the behaviour of microbes in the gut. He is less than impressed with the response of the media to the Science paper on FTO. “Basically, no amount of genetics can explain how humans have got fat so fast,” he told me. I would have to agree, genetics has long-term effects one usually does not see major changes in body function and form happening across a single generation.

So, might there be an alternative explanation for the apparent obesity epidemic in the developed world? Nicholson thinks so. “Changes in the gut microbes and caloric bioavailability probably could be the explanation,” he says. If we are suffering severe disturbances in the profile of gut bacteria – either they have changed behaviour or the species have changed – then those heading for overweight or who are already obese could be absorbing far more calories even from the same amount of food because of it.

Liposuction, like Vaser, Smartlipo and laser liposuction is one option, but could a dose of live yogurt or an antibiotic regimen be the solution to obesity? We are only just starting the hors d’heuvre when it comes to understanding the interplay between our bodies and microbes. Much more work into metabolism and the role of the guy microflora needs to be done before we can cast aside obesity as yet another genetic construct and so abandon sufferers to the realm of the untreatable.

Nicholson explains that the microflora in our gut are laid down in infancy and there is not a lot we can do about that. However, he says, “The real secret is eating a lot of beans and pulses (lentils etc) – lots of them every day, they keep the lower gut microbes very happy and the products of their
breakdown (catabolism) do not cause diabetes.” Nicholson laments that the windy side-effects of such a diet are far less malign than the problems associated with a diet deficient in beans and pulses.

Genetics, microbes, and beans aside, Nicholson has what I think has to be the final word on the debate: “Even genes and bugs added together still fade into insignificance if you sit on your butt all day eating pork rinds – you will get fat but its not genetic!”

R&R leads to molecular recovery

Mark Kuzyk is at it again. The physicist continues to explore a range of novel, light-sensitive compounds and has found one that degrades over time…but if kept in the dark for a short period of time, spontaneously heals itself. This amazing property could be exploited in industrial processes such as optical data storage and photolithography, which could use the recyclable material instead of having to replace the expensive stuff for every turn over.

Kuzyk and colleagues at Washington State University have found a molecule that loses its ability to fluoresce when bathed with laser light but regains this talent if it gets plenty of rest in the dark. Recovery starts during a half hour power nap and is complete after a good eight hours R&R, say the resarchers.

“It’s almost as if you have a piece of paper that’s yellowed over time, and you put it in a dark room for a day, and it comes back brand-new,” enthuses Kuzyk. Previously, I discussed Kuzyk’s work on Sciencebase and Intute Spotlight.

Kuzyk and students Ye Zhu and Juefei Zhou discovered the “self-healing” property of the dye AF455, which excels at two-photon absorption, an important property in optical data storage and in producing microelectronics for photolithography. The team will report details in the April 15 issue of the journal Optics Letters.

I received a follow-up email to this from Kuzyk: I’ve reproduced the Mark Kuzyk email here.

Getting up close and graphic with graphene

Graphene recently hit the headlines as a potential replacement for silicon in a future world of molecular computing. However, until silicon technology has run its course and arrays of millions of transistors can be carved at will from this material, scientists will have to be content with investigating its properties and devising novel uses.

Nevertheless an international team led by scientists at MIT has turned the Raman spotlight on graphene and its chemical cousins to help them explain the materials’ unique physicochemical properties.

Mildred Dresselhaus of Massachusetts Institute of Technology, USA, and colleagues there and at the Federal University of Minas Gerais, Brazil, Tohoku University and CREST, Sendai, Japan, point out that Raman spectroscopy has played an important historical role in understanding graphitic materials. Most usefully, Raman can reveal information about defects and stacking of graphene sheets. The team has now used Raman to look at the modern counterparts of these materials, nanographites and individual graphene molecules.

You can read the whole story in this week’s SpectroscopyNOW news round-up from David Bradley.

Workout limits

Do you workout hard? Is “no pain, no gain” your exercise ethos? Do you feel like you are not getting the fitness results you expect? Your brain could be to blame.

Yagesh Bhambhani and Rohit Malik of the Faculty of Rehabilitation Medicine, at the University of Alberta, Edmonton, Canada and Swapan Mookerjee of Bloomsburg University, Bloomsburg, Pennsylvania, USA, have monitored the oxygen levels of blood flowing in the brains of healthy volunteers while they worked out using near infrared spectroscopy.

NIRS can evaluate changes in blood volume and oxygen levels in the brain while people exercise by measuring the absorption of this form of electromagnetic radiation by the blood, which varies depending on how much oxygen is present.

The team has found that even if you are healthy, there could be an upper limit on just how hard you can push yourself, because brain activity begins to be affected detrimentally as you push harder and harder.

The study watched blood flow and volume as well as measuring carbon dioxide breathed out during an incremental exercise test. In the tests, exercise intensity is gradually stepped up until the volunteers reach exhaustion and must stop. The observed fall off in carbon dioxide levels coincided with decreased blood flow to the brain, which affects exercise capacity, the researchers say.

You can find out more about the science behind the exercise threshold here. Of course, if you are not pushing your exercise regime to the limits, then you probably have nothing to worry about. More to the point, the research is aimed at fine tuning finely tuned athletes and others, not providing the sedantary or mediocre with an excuse to give up half way through their treadmill cycle. (Ahem, mentioning no names…)

Magnetic control

MRI robot Think of MRI and most people think of medical scanning, the kind of analytical tool that can slice through your brain or other organs, virtually speaking, and produce a three-dimensiona view of your innards. But researchers in Canada are putting the magnetic in magnetic resonance imaging to a different. They hope to use it to control tiny robot devices that can be guided through blood vessels in an application reminiscent of 1960s sci-fi movie Fantastic Voyage.

The demonstration by Sylvain Martel of the NanoRobotics Laboratory at Montreal Polytechnic School could herald the emergence of a new form of surgery that uses MRI to control “untethered” devices within the body. The team has spent the last several years developing microelectrochemical systems (MEMS) that could be used in diagnostics and treatment and have now successfully guided, an inactive prototype device for the first time through an artery (see picture) using computer-controlled MRI. More details here.

Alchemy bonus

The Alchemist this week discovers how a bodybuilders’ supplement might help treat Parkinson’s disease, the route taken by mercury from groundwater to coast, and how to boost your storage space with fullerenes. Also this week, physical condensation problems solved and how Raman spectroscopy is laying it on thin to help scientists understand carbon sheets. And, this week’s award goes to Perry McCarty for his pioneering work in understanding waste water chemistry and microbiology. Alchemical happenings on ChemWeb

If you missed the previous instalment, we discovered proof positive that Asian pollution could affect global weather, how to scratch fatty acids from the surface of stone buildings, and discovered hundreds of new drug targets for the battle against cancer. We also did a spot of spring cleaning with a new type of duster for mopping up even the tiniest toxic particles and found out how filling up in the UK became more expensive than ever thanks to an inadvertent silicon injection into fuel. Find out more in the older Alchemist

Cool cats make heavy metal fallout

The rapid adoption by the car industry of catalytic converters for petrol engines to reduce NOx and other pollutants has significantly improved the quality of air in busy towns and cities. However, Italian scientists says this improvement has comes at a significant price as they are finding rapidly rising levels of heavy metal fallout that could have serious implications for health.

Claudio BotrÃ¨ of the University of Rome and Alessandro Alimonti of the Italian National Institute of Health in Rome and their colleagues explain that the increasing numbers of catalytic converters on the road has led to rising environmental levels of the metals used as the catalysts in these devices – platinum, rhodium, palladium, and iridium. The team has published their detailed findings in the International Journal of Environment and Health.

More on this in a media release on AlphaGalileo

Free software shows how drugs work

Partition coefficient If you are already a user of free chemistry drawing package ACD/ChemSketch but need a little more physical information from your tools than simple structure drawing, then ACD/Labs’ latest freebie might be right up your street. They just released ACD/LogP, which can be used to extract a lipophilicity prediction from your structures with a few mouse clicks.

For those not in the know, logP, is the octanol-water partition coefficient and is a useful value assessing how a putative drug might partition between cell membranes and cellular fluids. It gives you an indication of potential oral availability in other words. This allows drug designers to find out early on whether they will need to do additional work to make a compound available by mouth.

logP isn’t only about drugs though, agrochemists can use it to help them predict how their experimental compounds might partition between different species. This allows them to see whether a compound might target particular pests in preference to beneficial insects, for example.

This property is also useful to flavour and fragrance scientists who can judge in silico how a new compound might behave when added to food or dabbed on the skin as perfume.

ACD’s physical chemisty products manager Greg Pearl explains that making logP available to the community for free will not only support research but will help students and educators get to grips with this important property. ‘Freeware is especially valuable to educators and students with limited resources,” he says. “For example, during a lecture, an educator can interactively demonstrate how subtle changes to a molecule changes it physical properties – much more compelling than discussing a table of numerical results. It also gives students a chance to use the types of tools they will encounter in the workplace.’

“Through this release of ACD/LogP freeware to scientists worldwide we continue our tradition of advancing chemical research by making critical physicochemical properties available to scientists in an open-access environment,” Pearl adds. “Users will benefit from over a decade of algorithm refinement resulting in accurate and reliable predictions.”

Just for the record, ACD/Labs hosts the Reactive Reports chemistry webzine. There’s more information about logP on their site here

Magnetizing a Baby

It is possible to magnetize a baby with a few drops of water, some ordinary sugar and a teether. It’s all down to changes that take place in the brain when the baby tastes the sugar.

Neal Barnard MD, founder of the Physicians Committee for Responsible Medicine (PCRM), explains the process. Of course it’s not really magnetization, it’s the release of opiates in the brain, natural versions of morphine and heroin, that make us feel good. Barnard discusses the science underlying food addictions. Personal willpower is not necessarily to blame, chocolate, cheese, meat, and sugar all release these opioids. substances. Dr. Barnard also discusses how industry, aided by government, exploits these natural cravings, pushing us to eat more and more unhealthy foods. He suggests that a purely plant-based (vegan) diet is the solution to avoid many of these problems.

He points out how cheese and other dairy products contain natural compounds closely related to morphine, perhaps as a natural bonding chemical to ensure suckling mammals “enjoy” the suckling process. The presence of tiny quantities of these compounds in so many foods could explain why dairy products, chocolate, wheat, meat, nuts, onions, corn, tomatoes, onions, bananas, citrus fruits etc are common dietary triggers of migraine, for instance, users are simply overdosing on the opiates and then suffering withdrawal symptoms. And, as to cardiovascular disease, stroke, and heart attack…cardiologists know that if a man in his fifties presents with impotence, there is a one in four chance that he will have a heart attack or stroke within two years. Barnard blames our addiction to meat and even got cattle ranchers in the mid-west to prick up their ears when he relayed that fact and had them asking for his tofu recipes and tips on cooking brown rice.

Anyway, it’s a long video (40 minutes) but makes very interesting viewing.

No flies on this chemical web

The latest, and potentially the greatest, in freely accessible chemistry database went live at midnight EST to coincide with the start of this year’s ACS Annual Meeting in Chicago. ChemSpider was built to aggregate and index chemical structures across the web together with their associated meta data and provide a single searchable repository available to everybody, for free. Structure identifiers such as SMILES, InChI, IUPAC and Index Names as well as numerous physicochemical properties are embedded with each database entry, of which there are 10 million at the moment. According to the site FAQ, “We intend ChemSpider to offer the fastest chemical structure searches available online and delivered with the flexibility and usability necessary to encourage repeat usage.” Chemists among the Sciencebase readership will no doubt already be clamouring to try out the beta release and to compare it with the likes of PubChem and ChEBI.

There are dozens and dozens of chemical structure databases across the web, but no simple way to search all of them. Some are curated from the research literature others are vendor catalogues, and yet others are molecular properties, environmental data, toxicity data, analytical data repositories. ChemSpider will aggregate all of these (even the commercial ones) into a single database, so providing pointers to virtually all the available information. Many of the end pages users will reach will be open access and free while others will require a paid login ultimately. Regardless, at least you will know whether or not information exists on those structures and you can then choose to subscribe or not to the external information.

Okay, so if this post is starting to sound a bit too much like an advertisement for ChemSpider, I have to confess something of a vested interest. As part of the launch, Sciencebase has collaborated with the good folks at ChemSpider to bring you the site’s very own webzine (all puns intended!) – Spinneret. And, in case you’re wondering what exactly a spinneret is, you can find out on the site’s About page. Don’t forget to subscribe to the Spinneret RSS to keep ahead of the game and find out how Spinneret is weaving the chemical web one molecule at a time (another of those puns, sorry).