Chemistry – Page 42 – David Bradley

Painkiller in saliva

A natural analgesic (painkiller) that is six times stronger than the opiate morphine has been found in human saliva.

In 2003, Catherine Rougeot and her colleagues at the Pasteur Institute identified a potent pain sensation inhibitor in rats they called sialorphin. The present work confirms the presence of a related compound in humans. The compound inhibits the same class of proteins as sialorphin.

The analgesic, termed opiorphin (someone not related to the research team registered domain name opiorphin.com yesterday!) is a peptide with the amino acid sequence: tyrosine glutamine arginine phenylalanine serine arginine.

In rat studies, injections of opiorphin suppressed pain sensation for both chemical-induced inflammation and acute physical pain. In both cases, the administered dose of 1 mg/kg opiorphin provided the same painkilling power as 3-6 mg/kg of morphine.

The authors hope to next identify which physiological conditions trigger the natural release of opiorphin, but also note that the strong analgesic properties of opiorphin warrants potential exploration for clinical pain management. However, Rougeot cautions that it might not be developable as a conventional painkiller as the compound may also have anti-depressant activity.

I’m curious though, if spit has this potent painkiller why does it hurt so much when you accidentally bite your tongue?

The work is reported in this week’s issue of PNAS.

What are molecular sieves

As the name might suggest these are molecules that can sieve out other molecules, acting like a filter but on the molecular scale. They are usually composed of a highly porous mineral or organometallic compound, the tiny pores of which are usually of uniform size and shape.

Clays, porous glasses, microporous charcoals, active carbons, aluminosilicate minerals, zeolites, and various synthetic compounds which we’ve discussed in Elemental Discoveries in the past allow much smaller molecules to enter and either pass through or be adsorbed on to the inside surface of the molecular sieve. As such. molecular sieves can be used to absorb liquids and gases. For instance, water molecules are often small enough to enter such porous materials while larger molecules are not, making molecular sieves useful as drying agents, or desiccants. A molecular sieve can absorb water up to 22% of its own weight. The petroleum industry makes wide use of molecular sieves for purifying gas streams. You can find out more here.

For more on molecular sieves research check out the Elemental Discoveries archive and the Reactive Reports website.

Performance enhancing steroids

Most sports stars know that injecting steroids to boost performance is plain stupid. But, some do it anyway, because the potential gains, they reason, outweigh the risks to health and the chances of being stripped of glory are much smaller than their chances of winning the medal without them.

Not all steroids are purely about enhancement. Another group of steroids, known as corticosteroids, are used to reduce inflammation and pain following injury. Alarmingly high doses are often used to speed up the recovery process but with potentially serious side effects on the tissues into which they are injected. As such corticosteroids injections are also banned in sports.

However, there is a drug produect available to errant sports people that can stimulate the body’s own production of corticosteroids, it’s a protein known by the tradename of Synacthen. It was essentially undetectable as only tiny quantities are needed to cause the desired stimulation and such small concentrations are easily lost in the background noise of other more abundant proteins in a blood sample.

Now, researchers writing in the journal Rapid Communications in Mass Spectrometry have developed an analytical separation and detection technique, based on chromatography and mass spec, that can pin down this elusive drug and render the cheats visible even if the compound is present only in incredibly low concentrations in a blood sample; even at 10,000,000 times lower concentration than other proteins in the blood plasma.

‘If the drug testing authorities adopt this new test it will close a gap in the current drug testing system, and mean that athletes will no longer be able to get away with this form of cheating,’ says lead author Mario Thevis, who works in the Center for Preventive Doping Research — Institute of Biochemistry, at the German Sport University Cologne in Germany.

Looks like a few well known sports celebs will have to start using RICE for their injuries again…

Get research papers free

Wouldn’t it be great if you could get all those research papers you need for free without having to wait for the publishers to all convert to open access?

Well you can, kind of.

Most of the time when you scroll through the ToCs (table of contents) pages at a publisher’s site, you’ll see a little red “free” symbol next to the abstract. Click for “full paper” or “pdf” and you’re usually taken to a login page where you have to enter your subscriber username or password. That’s fine if you’re at an institution with a site-wide licence for the content, but what if you’re away from your lab and don’t have a remote login?

Well, not everyone has noticed but some of the major journals do make their content free after a set time period. Papers in PNAS, for instance, are free after six months, no login required. But, six months is a long time in research and may be too late if you’re after the most cutting edge info.

Physicists of all flavours are fairly well served with preprints courtesy of the LANL preprint server, just head on over type in your keywords and pull up papers that haven’t even been published by the journals (yet). You can read the most recent physics preprints here. Physicists after IOP journals are also well served, this publisher gives free access to papers for the first 30 days after publication, which is rather unusual.

Biological chemists are fairly well served too, at least when it comes to the Journal of Biological Chemistry, which offers pre-edited papers that have been accepted, so-called “pips” (papers in press) for free. Once the papers go live, they’re pay as you go, but until then you can grab them for nothing more than a few mouseclicks as long as you don’t mind that some t’s may not have been dotted and a few i’s may have been left uncrossed. Set yourself a Google Alert to tell you when that page changes, export it as a newsfeed or have it emailed and you’ll be able to grab the papers as soon as they appear at zero cost. Same goes for Biol Reprod and several other journals. Also in biomedical is PubMedCentral, but that’s one of those OA systems, rather than freebies by the back door. More OA journals can be found at DOAJ.

For scientists who publish in Springer journals they can make a one-off payment of $3000 at the time of writing to allow their paper to be made available to readers for free. It’s like paying for infinite digital reprints, which works out at a very small cost per reprint and is probably well within the reach of only the most prominent labs, or multi-author papers where everyone chips in a few bucks to get the word out as far and wide as possible.

Crystallographers are well served too – one source of OA crystallography material can be found here.

For chemists a quite comprehensive list of free chemistry journals can be found here and there is also Chemrefer, which we have mentioned previously which lets you search by keyword for freebie papers.

Irish chemistry thrives on spin

Irish chemistry Peace talks and an IRA ceasefire were only dreamed of the last time I visited the city of Belfast in Northern Ireland and the Queen’s University. Indeed, at the time there were still a few grey armoured vehicles on the streets and the city centre was still gated. There were British soldiers patrolling outlying villages and on the day I departed there was a major bomb scare at an unopened shopping centre, which meant a long-winded taxi diversion back to the airport. Times have changed.

Beyond the snazzy new university logos, truncated Qs, and mission statements lies a thriving department at Queen’s University Belfast that has attracted to its membership several high-performing researchers from some prestigious international laboratories. Among them are such rising stars as Frederic Meunier who has worked with pioneering catalytic chemist Marc Ledoux at Strasbourg, Raman spectroscopist and Innovative Molecular Materials scientist Steven Bell, and Joe Vyle an alumnus of the laboratory of Marv Caruthers in Boulder, Colorado, who invented the chemistry used during the past 20 years for synthesising DNA on machines. And, of course, AP de Silva whose pioneering work in molecular logic has already led to multimillion dollar sensor technologies and is making inroads into the world of combinatorial chemistry through the development of molecular computational identification (MCID)

Alternatives to animal testing

Despite the claims of extremist animal protesters, scientists do not in fact relish the use of animals in tests of new pharmaceutical and other chemical products and are continually searching for valid alternatives that might reduce the numbers of small mammals, for instance used in pesticide safety tests.

According to Jennifer Rohn writing in this week’s issue of Chemistry & Industry magazine, the thousands of test animals currently need for pesticide evaluation might be replaced by tricking ticks into setting up home on a faux cowhide. The hide, developed by Swiss researchers consists of a skin-like silicone membrane, complete with hair that rests over a layer of cow’s blood. The insects are so comfortable with the faux-cow that they set up home, mate and lay eggs.

Currently, some 10,000 animals are used annually to test new tick-fighting chemicals because pesticides to kill Lyme-disease carrying ticks and other insects are constantly being updated.

Thomas KrÃ¶ber and Patrick Guerin at the University of NeuchÃ¢tel confirmed the effectiveness of their test bed using a standard tick pesticide, firponil, and observing central nervous system damage revealed by leg trembling in the ticks. They report details in the journal Pest Management Science.

Vicky Robinson, chief executive of the National Centre for the Replacement, Refinement and Reduction of Animals in Research, said: This research takes a simple idea and applies it to great effect, resulting in a potentially significant impact on animal use. Most importantly, it demonstrates that finding ways to reduce the use of animals in research and testing is as much about improving the science as it is about considering the welfare of animals.’

Obviously, the tick test avoids the need to test on rodents or other laboratory mammals, but it remains a devastating blow to tick lovers everywhere.

Metallic BO

“The smell of iron upon contact with skin is ironically a type of human body odour,” explains Dietmar Glindemann. “That we are smelling the metal itself is actually an illusion.”

Many people notice a peculiar “metallic” smell when handling iron objects, such as tools, utensils, door handles, railings, firearms, coins, and other objects. But, iron untouched by human hand has a subtly different almost garlic like smell. Dietmar Glindemann of the University of Leipzig and his colleagues Andrea Dietrich at Virginia Polytechnic Institute and State University, and Hans-Joachim Staerk and Peter Kuschk of the Leipzig Environmental Research Center, Germany, have used a sophisticated analytical process to sniff out the reason why. It transpires that the metallic smell of iron that has been touched is a kind of body odour rather than a smelly metal.

More… (fixed link)

For those worrying about other kinds of BO, chemists and microbiologists have an answer to why some people smell the way they do. The research reported in Reactive Reports might one day lead to a new type of deodorant for even the smelliest of pits.

If you’re interested in how armpit scents can affect other people here’s an article from my days freelancing for The Guardian that explains how “eau d’armpit” might be used to treat pre-menstrual syndrome.

Science Teacher Gets Flashed

I remember seeing some dull old film clip of the thermite process in action during school chemistry class. Much better would have been to see it live, in the schoolyard with a science teacher dumb enough to head back over to the reaction vessel because it hadn’t fired up quickly enough. Well, for those who missed out there’s a nice video of that very happening.

What I cannot understand is why those students and the first teacher are not wearing some kind of protective goggles and why they’re not behind a safety screen of some sort. If you did this kind of thing in a British chemistry class OFSTED would put the school on special measures quick as you could weld two chunks of metal together with aluminium (aluminum) powder and iron oxide at 2500 Celsius. D’oh!

Chemistry really adds up

AP de Silva was born in Sri Lanka but moved to Queen’s University of Belfast, in the 1970s and is now Professor of Chemistry. His fascinating research into small logical molecules has found commercial application in diagnostics and sensors, has recently led to a breakthrough in labelling compound libraries, and may one day help us build a molecular computer.

Read my interview with AP in Reactive Reports to learn a little more about the man behind those glowing molecules that truly add up.

Cultural evolution in the lab

Adding a little culture to the chemical laboratory could help chemists find structures much faster than before. According to UK chemists, Samantha Chong and Maryjane Tremayne, of the University of Birmingham, combining the principles of social and biological evolution with a little fashion sense to make a new Cultural Differential Evolution algorithm allowed them to half the time it took to solve the structure of a molecule from its powder diffraction data.

Their research could have widespread application in solving a variety of global optimization problems in chemistry, nanoscience and bioinformatics.

The use of evolutionary algorithms is a relatively new approach to solving problems based on mimicking the principles of “natural selection” and “survival of the fittest”. The Birmingham team reasoned that the much more rapid social evolution experienced by humans, essentially fashion sense, could be merged into an evolutionary algorithm to help reduce the number of likely candidates for a particular structure much more quickly. They have now demonstrated how this works on two compounds, a previously unsolved structure and baicalein, the active ingredient in the Asian herbal medicine “Sho-saiko-to”.

Read on…