Author: David Bradley

Styrofoam and Polystyrene

It’s not an excuse to use more plastic cups at the office water cooler, but Irish and German researchers have discovered that the soil bacterium Pseudomonas putida can eat polystyrene. This polymer, instantly recognisable in its expanded form is a key component of disposable cups, and in “plastic” plates and utensils.

Turning it into an eco-friendly plastic would significantly reduce the environmental impact of this ubiquitous, but difficult-to-recycle waste stream, according to a study scheduled to appear Kevin O’Connor of University College Dublin and colleagues there and in Germany publish details of their work in the April 1 issue of Environmental Science & Technology, but their research is no joke.

Worldwide, more than 14 million tonnes of polystyrene are produced annually, according to the US Environmental Protection Agency. Most of this ends up in landfills. Although polystyrene represents less than 1 percent of solid waste generated in the US, at least 2.3 million tons of it is dumped in US landfills annually. Just 1 percent of polystyrene waste is recycled.

The microbe is a special strain that can convert petroleum-based plastic waste, produced by pyrolysis to convert it into styrene oil, into a reusable biodegradable form. The result of microbial intervention is a biodegradable plastic known as PHA (polyhydroxyalkanoates). O’Connor suggests that a similar process might be used to convert other types of discarded plastics into PHA.

PHA is used in medicine and for plastic kitchenware, packaging film and other disposable items. It is resistant to hot liquids, greases and oils, but unlike polystyrene, it readily breaks down in soil, water, septic systems and backyard composts.

Stroke Immunity

Proteins involved in the inflammatory response could be used to help in brain
regeneration following cerebral stroke, according to Swedish researchers writing in the EMBO
Journal today.

Complement proteins participate in the inflammatory response and scientists have suggested that under abnormal circumstances, following stroke for instance, their role in inflammation could contribute to tissue damage in the brain. This new research, by Marcela Pekna and colleagues of the Sahlgrenska Academy at Goeteborg University, reveals surprisingly that complement proteins may also have a beneficial role.

Pekna’s team have shown for the first time that neural stem cells and neural precursor cells express receptors for complement proteins and that the complement system positively regulates the maturation of neural cells in adult mice both under normal circumstances and during brain
regeneration after a stroke. A better understanding of the dual role of the complement system in stroke, and possibly other central nervous system (CNS) pathologies, may help researchers to design more effective therapeutic strategies by developing complement inhibitory agents that
neutralize the adverse aspects of complement activation while enhancing those that are neuroprotective and facilitate repair.

The paper is available online at http://dx.doi.org/10.1038/sj.emboj.10974

Sporty Nanotubes

Integrating stiff carbon nanotubes into more traditional materials, such as polycarbonates, can dramatically improve the material’s ability to absorb vibrations, especially at high temperatures, according to US researchers. The discovery could lead to new composites for aerospace and automobile engineering applications as well as improving golf clubs and other sports equipment. You can read the complete story in this month’s Reactive Reports.

Funnel Back Search Engine

A search engine spun out from the Australian research organisation CSIRO is already powering the Australian Government Information
Management Office, Westpac Banking Corporation, the Australian Broadcasting Corporation, the University of Sydney, National Research Council of Canada, University of Staffordshire, and the Scottish Care Commission and could soon offer users from multinational down to SOHOs a way to search their websites, intranets, file-shares and databases that side-steps the security risks associated with other desktop search engine software that has recently come to light.

“Funnelback is a better search engine because of its superior ability to
help users find the information they are looking for quickly and
accurately,” says Dr Stephen Kirby, Chairman of Funnelback Pty Ltd. [That has to be one of the most trite press release statements ever, Ed.]

Nevertheless, the “new” search engine could improve the lot of scientists who only see so much spam and commercial garbage when searching with the more commonplace SEs.

According to the Funnelback development website, however, the SE “offers a better search experience based on its high-quality ranking algorithms.” These it claims take into account many factors when ranking a document. So far, nothing new, the likes of Google have been doing that for years.

Indeed, the Funnelback site spells out exactly what it uses to rank a webpage:

* The anchortext pointing to the page
* The number of incoming links from other pages and sites
* The length of the page address (URL) and the presence of query words in the URL
* The number of times your query words appear in the page and in the collection, and the length of the page

So, basically, it ranks pages in pretty much the same way as Google. Of course, we’re not going to be “Funnelbacking search results” like we “Google” them in our everyday searching. “We’re not tackling the global web search market dominated by Google, Yahoo and MSN,” Funnelback’s Francis Crimmins told us. He adds that “we have a strong story in the enterprise and hosted search space.” One additional interesting aspect of this SE is that Funnelback, as well as carrying out basic web ranking, supports a “free-text + metadata search”.

Benzene Soda

Sodium benzoate (E211) is a public health issue that has been bubbling for fifteen years and could soon come to a head and have the fizzy drinks industry frothing at the mouth.

Sodium benzoate is a preservative added to carbonated beverages, but those drinks that also have added citric or ascorbic acid (vitamin C, E300) can be susceptible to the formation of benzene as a degradation product. At least that’s the theory.

The US Food & Drugs Administration (FDA) was aware of this issue in the 1990s and alerted manufacturers who were then meant to introduce a “quick fix” to prevent this carcinogenic degradant from forming in amounts above safety levels. However, there have been hundreds of new susceptible beverages brought to market the world over since by smaller manufacturers as well as the well-known ones and seemingly the benzene message has been lost in the intervening time.

Germany’s food watchdog, BfR, and the UK’s Food Standards Agency are currently testing drinks to see whether benzene levels are above WHO recommendations. Other countries are also on the alert. The renewed concern follows the FDA’s re-opening of an investigation, closed for 15 years, into benzene in soft drinks.

You can read more details of this at industry newsletter Beverage Daily

Some studies have shown that levels of benzene are present at five times the WHO’s limit for drinking water contamination and can occur in bottled soft drinks exposed to heat and light especially.

In acid conditions, benzoate is converted to benzoic acid (the active antimicrobial form, benzoate is added as a preservative for a reason after all) and it is thought that it interacts with hydroxyl radicals released by the ascorbic acid (better known as vitamin C) reaction with iron or copper ions in the water. These hydroxyl can decarboxylate benzoic acid, releasing carbon dioxide and leaving benzene behind. But, at what rates this occurs is not clear.

Moreover, leaving out the ascorbic or citric acid from soft drinks would be the simple solution and avoiding benzoate as a preservative in foods that contain these acids naturally would offer an end to the “problem”.

However, the issue brings to the fore once again the issue of acceptable risk. Sodium benzoate is present in soft drinks only in very small amounts and even if degradation were complete, the risk to someone drinking it is tiny. To have the same exposure as lab animals used to demonstrate carcinogenicity would mean a person having to drink 10,000 bottles of benzoate-containing soda.

Still, such minor details will not stop the media from jumping on this as the next big scare story despite the fact that it’s been around for years as public chemophobia.

Good Corrosion

Chemical corrosion impacts on global commercial turnover significantly as equipment, buildings, and transportation systems have to be continually maintained to combat its effects. Chemists ever looking for the silver lining, however, have recognized that chemical attack of metal surfaces is not all bad and might be exploited to produce useful nanoscale surface features with potential technological applications in catalysis, sensors, and other areas. Read on in the latest issue of Reactive Reports

Pubic Immunity

Differences in immune response between males and females appear at puberty, according to a study published today in the journal BMC Immunology.

The differences in the male and female immune responses, which make females more prone to autoimmune disease and males more subject to infection, are established during puberty, report US scientists who have identified one of the mechanisms responsible for the difference in immune response between male and female mice. They show that this sexual disparity is established during puberty and is influenced by sex hormones. These findings have implications for studies of autoimmunity, transplantation and vaccination.

Kanneboyina Nagaraju and Eric Hoffman’s groups from the Children’s National Medical Center, Washington DC, and colleagues elsewhere in the USA, used microarrays to study 12,000 genes expressed in the spleen of pre-pubertal, pubertal and post-pubertal male and female mice.

The results show that a number of genes are upregulated in both males and females during puberty. The authors found that genes involved in the innate immune response, which provides an immediate defence against pathogens and involves phagocytic cells such as macrophages, were significantly underexpressed in pubertal and post-pubertal females. Genes involved in the adaptive immune response, which provides a long-lasting protection and involves antibodies or ‘immunoglobulins’, were overexpressed in pubertal and post-pubertal females compared with males. This difference in expression was not found in pre-pubertal mice, indicating that the sexual disparity in immune system expression is established during puberty.

The researchers have also demonstrated that the differences in immunoglobulin expression between males and females are controlled by a gene signalling pathway called the Fas/FasL pathway, which is modulated by the female sex hormone estrogen.

SOURCE: BMC Immunology press release.

Interview with NMR Expert Gary Martin

In the latest issue of the Reactive Reports chemistry webzine, we interview NMR expert Gary Martin about his experiences with this powerful analytical technique and his views on the future of the technology and novel applications.

Martin spent the first 14 years of his career at the University of Houston before moving to Burroughs Wellcome, Co., in 1989, and then to Upjohn in 1996, which, through a series of mergers and acquisitions, left him working for Pfizer a few years ago. He has spent much of his career focused on the identification of natural product structures and subsequently synthetic compounds originating in drug discovery, and more recently the identification of impurity and degradant structures of drug molecules. In the Spring, he takes up a new position at Schering-Plough’s facility in Summit, New Jersey, where he will no doubt use his pioneering NMR techniques to the full once more.

Possible childhood depression asthma link

According to a report published today in the International Journal of Obesity, childhood depression is linked to adult onset of asthma and obesity. Gregor Hasler and colleagues analysed data on 4,547 subjects at six times over a 25 year period from 1978. The study reveals for the first time an additional link to depression alongside the other conditions.

The authors investigated how many of the people suffered from childhood depression and compared this with those who later became obese or developed asthma. Using data from a prospective community study collected over a 20-year period they were able to explore the role played by symptoms of depression in associations between asthma and body weight. The study concludes that depressive symptoms during childhood are associated with adult obesity and asthma. The research should not only help improve our understanding of the pathology of obesity and asthma but hints that the neurobiology of depression is different at the time of childhood and adolescence when compared to adulthood.

As ever with this kind of research, the team covers its collective back with a caveat arguing that “further research into the mechanisms and psychosocial factors is required.” That also means they’ve got something to include in their next grant application, of course.

Novel Prize Controversy

Regular sciencebase visitors will be well aware of my interest in what keywords visitors use to either find the site or to search the site once they’re here. Four hits on the site this month were after Novel Prize controversy, again and again. I’m not sure what they hoped to find by adding that phrase “again and again”, but more to the point, I’m not aware of any Novel Prize. If they’re after the Nobel Prizes, then sciencebase offers a run down of those in Chemistry, Physics, and Medicine.