David Bradley – Page 299

Hey good looking, what you got cooking, in those genes?

Attractive people Here’s a puzzle. If evolution ensures that ‘good’ genes spread through a population, then why are individuals so different? Why don’t people get better and better looking through each generation to the detriment of ugliness and lead to a population of real lookers?

The problem with current evolutionary theory is that it would seem that if females select the most attractive mates, then the genes responsible for their attractive features would spread quickly, leading to all males becoming equally attractive (think peacock tails). Ultimately, further sexual selection would then no longer take place and evolution would stop in its tracks.

This is the so-called lek paradox and it has remained a foil in the weaponry of the intelligent design advocate’s arsenal for many years. Until now.

Thanks to research at Newcastle University, England, this apparent fundamental flaw in Darwin’s theory of evolution, latched on to by creationists can be explained quite effectively by evolution itself. The findings of Newcastle’s Marion Petrie and Gilbert Roberts research suggests that sexual selection leads to increased genetic diversity by a mechanism not previously understood.

Petrie reasoned that as genetic mutations occur naturally anywhere in the genome, some will actually affect those used to produce the DNA repair kit enzymes found in all cells. This would lead to those individuals with a malfunctioning or inefficient repair kit, having more mutations left unrepaired and so greater variation in their genome.

Usually, damaged DNA leads to an unviable organism that either dies quickly of the effects or is otherwise unable to reproduce. However, if those variations are present in sections of the genome responsible for disease defence, then variation can actually be beneficial as greater variation in the genome at these points means more chance of warding of bacteria and viruses.

Petrie modelled the spread of genes in a population and demonstrated that the tendency towards reduction in genetic diversity caused by sexual selection is outweighed by the maintenance in greater genetic diversity generated by mutations affecting genome repair.

The researchers began this research a decade ago and their model genes are now a great fit for the observations of variations. “We find that sexual selection can promote genetic diversity despite expectations to the contrary,” Petrie says. The team publishes details of their findings today in the journal Heredity.

With this Ring

Bishnu Khanal and Eugene Zubarev of Rice University in Houston, Texas have found that nanoscopic gold roads coated with polymer can spontaneously self-assemble into rings within seconds of water droplets condensing on to the surface of a solution of the rods in dichloromethane solvent.

Nanoscale objects organized into superstructures are interesting because the properties of such tiny particles depend not only on their composition, shape, and size, but also to a large extent on their spatial distribution and the degree of their ordering within a superstructure.

Images obtained with an electron microscope show that the nanorods in the rings are oriented randomly when their concentration in the original solution is high. However, at lower concentrations the result is truly amazing: The nanorods are oriented in a head-to-tail sequence along the edge of the ring.

The team reports details of their results in Angewandte

Beating Heart Disease with Vitamin B Drugs

Niacin is involved in the metabolism or carbohydrates, fats and proteins, but at high dosage it can increase HDL more than a third and reduce levels of “artery-clogging” triglycerides by half.

Graeme Semple of Arena Pharmaceuticals, San Diego, reports how new drugs that raise high-density lipoproteins, so-called good cholesterol might be developed by following the lead of familiar B vitamin, niacin.

Researchers at Arena and elsewhere are trying to develop new drugs that are even more effective than niacin and so could have greater potential to protect at-risk people against heart attacks and stroke. Semple discusses the latest developments at the ACS annual meeting today.

You can read more about the biochemistry of niacin and LDL cholesterol in Sciencebase.

InChI=1/C6H5NO2/c8-6(9)5-2-1-3-7-4-5/h1-4H,(H,8,9)/f/h8H

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

Power Your iPod With a Cola

Got an iPod? Sick of having to charge it up at the electric outlet? Then try maple syrup or cola!

Researchers at Saint Louis University in Missouri have developed a fuel cell that uses sugar from almost any source from soft drinks (although not lite or diet versions though, so Coke Zero is out) to tree sap or even honey. They reckon their fuel cell could run three times longer than a conventional rechargeable lithium battery on a single charge. Better still, the fuel cell is itself biodegradable so at end of life it does not become a toxic burden on the environment like lithium or nickel-cadmium batteries.

“This study shows that renewable fuels can be directly employed in batteries at room temperature to lead to more energy-efficient battery technology than metal-based approaches,” explains team leader Shelley Minteer, an electrochemist at SLU. “It demonstrates that by bridging biology and chemistry, we can build a better battery that’s also cleaner for the environment.” Minteer reports her findings this week at the 233rd national meeting of the ACS in Chicago.

For more on how fuel cells might be improved, check out this recent item in Reactive Reports

InChI=1/C12H22O11/c13-1-4-6(16)8(18)9(19)11(21-4)23-12(3-15)10(20)7(17)5(2-14)22-12/h4-11,13-20H,1-3H2

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.

Blueberry Molecule Fights Colon Cancer

Pterostilbene, an antioxidant found in blueberries, has shown promise as a putative protective agent against colon cancer in animals, according researchers from Rutgers University and the US Department of Agriculture. Colon cancer is the second leading cause of cancer death in the United States and so a supplement or drug developed from this compound could potentially save many lives.

Rutgers’ Bandaru Reddy and colleagues reported their findings today at the 233rd national meeting of the American Chemical Society during National Colorectal Cancer Awareness Month.

“This study underscores the need to include more berries in the diet, especially blueberries,” says Reddy, “Although the blueberry compound wonÃ¢â‚¬â„¢t cure colon cancer, it represents a potential new and attractive strategy for preventing the disease naturally.”

Pterostilbene is also found in grapes a finding that was reported in Spinneret sibling webzine Reactive Reports in an item entitled Grape Expectations

InChI=1/C16H16O3/c1-18-15-9-13(10-16(11-15)19-2)4-3-12-5-7-14(17)8-6-12/h3-11,17H,1-2H3/b4-3+

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).

Could creatine slow Parkinson’s disease?

A North American study is set to investigate whether the dietary supplement, creatine, used by athletes and bodybuilders to boost their energy levels and build muscle could stop Parkinson’s disease in its tracks.

Creatine is already being investigated for treatment of other neurological disorders and neuromuscular problems, including Lou Gehrig’s disease and muscular dystrophy. According to Kapil Sethi, who is director of the Movement Disorders Program at the Medical College of Georgia, it might help Parkinson’s patients by giving the dying brain cells causing PD symptoms an energy boost too.

“We think it may help cells that are damaged or overworked,” explains Sethi. Sethi is a site principal investigator on the National Institute of Neurological Disorders and Stroke study. The study will enroll 1720 patients from 51 sites in the US and Canada.

InChI=1/C4H9N3O2/c1-7(4(5)6)2-3(8)9/h2H2,1H3,(H3,5,6)(H,8,9)/f/h5,8H,6H2/b5-4+

Reactive chemistry

Macrocycle The latest issue of Reactive Reports (#63) is now online featuring a selection of the hottest science news and our interview with the new Managing Director of the Royal Society of Chemistry, Dr Robert Parker.

Also in this issue:

Cocoa Has Beans One of the natural compounds found in cocoa, teas, wine, and some fruit and vegetables could lead to a breakthrough in health and nutrition, according to US researchers.

Chemists Go Round the Bend Chemists often think of molecular wires as “shape-persistent” rods with limited flexibility, so says Oxford University’s Harry Anderson, and he should know, having worked with the inflexible nanoscopic objects known as molecules since the early 1990s.

Natural Copy Cat Green plants can extract carbon dioxide gas from the air and turn it into sugar molecules using sunlight and give off oxygen. Now, a catalyst could help us do the same.

Waste Not, Want Not A fungus that can convert waste paper into an antibacterial and super-absorbent material has been discovered by researchers at BorÃ¥s University College in Sweden.