Archive for the ‘Subject Areas’ Category

Carbonic anhydrase inhibitors

New drugs need to be found that are capable of targeting carbonic anhydrases – a class of enzyme that catalyses the hydration of carbon dixoide to bicarbonate and H+. By inhibiting or activating these enzymes, a number of pathological disorders can be treated such as glaucoma, osteoporosis and cancer. Unfortunately, many of the drugs developed so far are not selective for the different isoforms of the enzyme.

Representation of the binding mode of an inhibitor compound in the active site cavity of the enzyme

Researchers from Italy have embarked upon investigating the inhibition of mammalian isoforms of carbonic anhydrase using N-substituted benzenesulfonamides. By employing X-ray crystallographic studies, they discovered a completely new binding mode with the enzyme. The team say that by substituting the moieties on the phenyl ring, unexplored regions of the enzyme active site could be targeted, allowing new lead compounds to be identified.

Read the ChemComm article to learn more about their findings.

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Revolutionising gene studies

A simple method for detecting a natural nucleobase in DNA could revolutionise epigenetic studies, say Japanese scientists.

5-Hydroxymethylcytosine is abundant in neuron cells and embryonic stem cells and plays a critical role in epigenetic regulation. Scientists are eager for a way to detect it, to help them understand how gene function is initialised.

The team discovered that peroxotungstate can detect 5-hydroxymethylcytosine by oxidising it to a thymine derivative, which can be visualised using gel electrophoresis.

Download the ChemComm article today to find out more.

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ChemComm poster prize awarded at NMR-DG 2011

Congratulations to Rob Evans (University of Manchester, UK) who won the ChemComm poster prize at NMR-DG 2011 Postgraduate Meeting held earlier this summer at the University of Birmingham.

Rob presented his work entitled ‘Predicting Diffusion Coefficients for Small Molecules’. He receives a prize certificate and a one-year print subscription to ChemComm.

Rob Evans receiving his poster prize certificate from Iain Day
Rob Evans receiving his poster prize certificate from Iain Day, who organised the meeting
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Bendy Crystals

Scientists are trying to create molecular systems that mimic machinery components. The idea is for these molecular machines to exhibit mechanical movement once an external stimulus is applied.

With this in mind, Japanese researchers have grown crystals that bend upon shining UV light on them. The crystals are of a salicylideneaniline compound which changes its structure depending on the wavelength of light.

The molecular transformation from the enol to the trans-keto form causes the crystals to bend on the macroscopic scale, which is also accompanied by a colour change from pale yellow to reddish-orange. When the UV light is blocked, the crystals resume their initial straight form and colour. This reversible bending can be repeated for over 200 cycles.

To find out more, download Koshima’s ChemComm article.

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Chemosensor could lead to fewer deaths from bacterial infections

Millions of people die each year from bacterial infections. Scientists have been searching for a low-cost way to quickly identify bacteria so disease can be diagnosed and treated at an early stage. 

Graphical abstract: Fluorescent DNA chemosensors: identification of bacterial species by their volatile metabolitesEric Kool and colleagues at Stanford University, USA, have developed fluorescent DNA chemosensors which they claim can sense and distinguish bacteria by the volatile metabolites they release. They tested the sensor on bacteria responsible for tuberculosis, food poisoning, pneumonia and sepsis and showed that it could accurately differentiate the bacterial strains. 

The chemosensors could be developed into quick, cheap and reliable reporters for early identification of bacteria in both patient samples and contaminated food, say the authors.

Want to find out more? Download Kool’s ChemComm communication to read more about how the chemosensors work. You might also be interested in the group’s recent Chemical Science Edge article, where they use fluorescent DNA to sense toxic gases.

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Yeast cell wall particles for multi-modal imaging

Scientists based in Italy and Portugal have developed a new carrier system for Magnetic Resonance Imaging (MRI) based on yeast cell wall particles (YCWPs).

YCWPs are well tolerated in vivo because they have a cell wall based on a glucan polymer. However, previous attempts at using it as a carrier of hydrophilic and amphiphilic chemicals have failed due to the porous and hydrophilic nature of the membrane.

In this work the team, led by Enzo Terreno at the University of Turin, realised that they could use the YCWPs as microreactors. Once loaded with an imaging agent the particles were exposed to a sudden change in solvent polarity therefore forming a micro-emulsion inside the particles. Importantly this traps the imaging agent in the particle core.

When loaded with gadolinium, the particles were found to have an increased paramagnetic density and also enhanced relaxivity per paramagnetic centre. In all, this should lead to better contrast when used for imaging. In the future Terreno envisages potential applications in cell tracking experiments and particularly for cells found in the immune system.

Want to find out more? Then download the full ChemComm article for free today.

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Colourful toxin detection

Scientists in Canada have developed a simple chemical detector that could be used to detect airborne neurotoxic organophosphorus chemical warfare agents.

Exposure to organophosphorus agents blocks the action of cholinesterase enzymes, which causes the neurotransmitter acetylcholine to accumulate in the brain. This rapid reaction causes bronchoconstriction (constriction in the airways in the lungs, owing to a tightening of surrounding smooth muscle), seizures, and finally death. Some agents, such as sarin and soman, are odourless and colourless, which makes them difficult to detect. Current detection methods require specialist equipment and trained personnel, so are of limited use in the field. 

The photoresponsive dithienylethene changes colour in the presence of an organophosphorus agent

Neil Branda at Simon Fraser University, Burnaby, and colleagues, have designed a chemical detector made of a dithienylethene compound that binds with organophosphorus agents in the same way that the agents bind to enzymes in the body. When the detector is bound to an agent, its structure alters, causing it to change from colourless to blue when exposed to UV light. This simple colour change provides a clear signal. Visible light resets the system by triggering the reverse reaction.

Read the full story in Chemistry World and download the ChemComm article to find out more about Branda’s research.

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Detecting caffeine

A team of researchers from Switzerland have used a commercially available fluorophore for detecting caffeine in water.

Previous methods for caffeine detection have been based on hydrogen-bonding receptors but these suffer from the need to use organic solvents. Whilst water-based detection has been achieved, the sensitivity and selectivity for caffeine was low.

Inspired by the known affinity of caffeine for polyaromatic compounds, Kay Severin and colleagues discovered that HPTS, a polysulfonated pyrene dye, can be used to selectively probe caffeine in liquid and solid samples. The team used the probe to quantify caffeine levels in soft drinks, coffee and painkillers, proving it can be used as a simpler alternative to HPLC.

Download the ChemComm article to find out more.

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Meet our author… Weiping Wang

Weiping Wang is now a Ph.D. student under the supervision of Professor Ying Chau at the Hong Kong University of Science and Technology. He has just passed his Ph.D. thesis defense and has been accepted into a postdoctoral position in Boston area. Weiping took some time out from his work to talk to ChemComm

Chau and Wang’s recent ChemComm article, Efficient and facile formation of two-component nanoparticles via aromatic moiety directed self-assembly,  presents a self assembling system based around Fmoc groups for the construction of nanoparticles.

What initially inspired you to become a scientist?

I grew up in a family of teachers and was influenced by my parents. I became interested in the natural sciences from a very young age. I spent my childhood making simple circuits, performing oil combustion, observing ant behavior. Becoming a scientist was a very natural path for me. After I started my Ph.D. my desire to become a scientist was consolidated. For me, scientific research is the best career in the world. You can accelerate societal development and bring benefits to the human race by investigating topics that interest you.

What was your motivation behind the research described in your ChemComm communication?

Aromatic groups conjugated with small molecules can engage in specific interactions to facilitate self-assembly. However, most synthetic small aromatic molecules self-assemble into nanofibrous structures, which are not suitable as drug delivery carriers. Inspired from the natural protein clathrin, we envisioned that a simple trigonal core molecule conjugated with three aromatic groups may achieve a rapid and efficient assembly into nanoparticles. Moreover, as drug delivery carriers, nanoparticles need to be well-dispersed at physiological conditions. This further motivated us to design this two-component self-assembling system employing aromatic interactions.

Where do you see your research heading next?

The two-step aromatic-directed self-assembling process allows us to introduce biofunctional peptides on the surface of nanoparticles. We have successfully prepared two-component nanoparticles functionalized by Fmoc-modified targeting peptides. The nanoparticles have shown attractive physicochemical and biofunctional properties for drug delivery application. Now the nanoparticles are being evaluated for encapsulating poorly soluble anticancer drugs and in vitro cytotoxicity. The idea of the self-assembling system may also inspire the construction of functional nanomaterials using other aromatic moieties. Other aromatic groups or even aromatic drug molecules may be formulated into a promising drug delivery system using a similar approach.

What advice would you have for young scientists considering a career in science research?

Passion is the most important factor to consider.

What do enjoy doing in your spare time?

Travelling, hiking, swimming and photography

If you could not be a scientist, but could be anything else, what would you be?

I think I would be an entrepreneur and start up a company with friends. I would like to know whether I can run a company well.

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Ginkgo biloba extract used to make Tamiflu

Graphical abstract: Extraction and isolation of shikimic acid from Ginkgo biloba leaves utilizing an ionic liquid that dissolves celluloseA new way of obtaining shikimic acid, the compound needed to make Tamiflu, has been discovered. Shikimic acid is normally obtained from star anise, a Chinese cooking spice. The shortage of star anise caused Roche problems a few years ago, when the demand for Tamiflu peaked during the H1N1 pandemic in 2009, so new sources are constantly being sought.

Toyonobu Usuki, from Sophia University, Tokyo, found that shikimic acid could be isolated from ginkgo biloba leaves using an ionic liquid. Ginkgo biloba is a tree mainly found in China and has often been used in Chinese medicine.

Find out more – read Usuki’s ChemComm communication.

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