Archive for the ‘Chemistry World Highlights’ Category

Schizophrenia: a disease of the brain?

Brain with question mark superimposed

The brain is usually considered as the most relevant organ of schizophrenia, but evidence suggests that peripheral tissues also contribute to the disease

Scientists in China have unearthed further evidence that a malfunction of the immune system contributes to the development of schizophrenia.

Schizophrenia is a severe mental illness, which affects around 1% of the world’s population. It is traditionally thought to be exclusively caused by problems in the brain. However, there is a growing body of evidence that suggests that the immune system has an important role to play.

Lin He and Chunling Wan from Shanghai Jiao Tong University, and their colleagues, identified over 1300 proteins in the blood and then compared the blood of schizophrenic patients with healthy blood using mass spectrometry. They found that 27 proteins were different in the schizophrenic patients and that all of these proteins were involved in the complement system.

See the full article in Chemistry World

Or read the Molecular BioSystems paper:

Label-free quantitative proteomic analysis reveals dysfunction of complement pathway in peripheral blood of schizophrenia patients: Evidence for the immune hypothesis of schizophrenia
Yang Li, Kejun Zhou, Liya Sun, Jinglei Yang, Ming Zhang, Baohu Ji, Kefu Tang, Zhiyun Wei, Guang He, Linghan Gao, Lun Yang, Peng Wang, Ping Yang, Guoying Feng, Lin He and Chunling Wan
Mol. Biosyst., 2012, DOI: 10.1039/C2MB25158B

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Fishing for chemical answers to biological questions

James K. Chen is an associate professor in the Department of Chemical and Systems Biology, Stanford University School of Medicine, US. He uses chemical tools to study developmental biology, including caged oligonucleotides that can regulate embryonic gene expression in zebrafish and other model organisms.

When did you decide to go into chemical biology?

It was when I was an undergraduate, during a lecture given by Stuart Schreiber at Harvard University. He was talking about his work on the immunosuppressive compound FK-506. His laboratory had found that FK-506, and another molecule called cyclosporin, inhibited the activity of calcineurin, a serine/threonine protein phosphatase. These studies were important because they implicated a role for calcineurin in T cell function and provided new insights into how T cell receptor signalling is transduced from the cell surface to the nucleus. After that lecture, I immediately knew that this was the kind of research I wanted to do. I loved organic chemistry, but I was more interested in answering the questions of biology. Using a small molecule to gain insight into a complex biological process was exactly what I wanted to do.

What can chemistry bring to developmental biology?

Chemistry can bring an understanding of biological mechanisms at the molecular level. It enables us to learn what is biologically interesting with molecular clarity. At the technology level, chemistry can help us to break through the natural system, for instance, chemists can make a molecule that doesn’t exist in nature and see the effect it has on a biological system. Chemical technology can break the bounds of biology.

What advice would you give to a chemist who is considering moving into biology?

A key difference between the two disciplines is the degree and level of focus – chemists tend to focus on techniques and they want to understand a system in terms of the simplest model possible; it’s a reductionist approach. With biology, you almost need peripheral vision – the system you’re trying to understand is like a forest, with complexity at many different levels and you have to be aware of it all. Often the simplest answer is not the correct one. Also, there’s a lot to learn, but it’s like learning a new language – if you immerse yourself in it, in time, you can know as much about your particular field as your biology colleagues do.

If you weren’t in this field, where would you have ended up?

I think I would have still been a developmental biologist, but any area of developmental biology is interesting to me. My interest isn’t focused on one particular organism; rather, it’s all about answering the key question: how does pattern form from nothing? It’s about basic architecture. Of course, developmental biology is also related to cancer biology, since many embryonic signalling pathways are dysregulated in tumours, but primarily my interest is fundamental rather than applied.

When you’re not doing science, what do you enjoy doing?

One thing I like to do is run; I normally do a half marathon every three months or so. Also I love fly fishing – it’s my passion. Once a year, I meet up with some old friends from our grad school days and we go fly fishing together. It’s a great way to catch up and enjoy nature at the same time. I love the outdoors so I enjoy anything that gets me out of the office into the natural world.

To read the full interview see Chemistry World and for some of James Chen’s recent research see:

Gene regulation technologies in zebrafish
Hanife Esengil and James K. Chen
Mol. BioSyst., 2008, 4, 300
DOI: 10.1039/b718447f

Chemical technologies for probing embryonic development
Ilya A. Shestopalov and James K. Chen
Chem. Soc. Rev., 2008, 37, 1294
DOI: 10.1039/b703023c

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Identifying the cause of pregnancy loss

Western blot analysis of ITI-H4 in RPL and normal patients. The fragmented ITI-H4 (36 kDa) was detected in 19 out of 29 RPL patients

A protein has been identified as a possible indicator of recurring pregnancy loss by scientists from Korea.

Kwang-Hyun Baek from CHA University, Seoul, and colleagues found that ITI-H4, a protein found in the blood whose function is unclear, was fragmented in the blood samples of patients suffering from recurrent pregnancy loss (RPL).

‘RPL is the loss of at least three consecutive pregnancies after 20-28 weeks,’ explains Baek who adds that over half of the possible causes are unknown. ‘We have seen a number of patients suffering from RPL without knowing the cause,’ he says.

Baek hopes to develop a diagnostic kit to screen RPL patients. ‘In the long term, we would like to develop a therapeutic approach to suppress the risk of RPL,’ he adds. ‘We’re not sure whether the fragmentation of the protein ITI-H4 is the result or cause of RPL so identification of its cellular mechanism is required to develop therapies.’

Read the full Chemistry World story online here or the full article at:

ITI-H4, as a biomarker in the serum of recurrent pregnancy loss (RPL) patients
Myung-Sun Kim, Bon-Hee Gu, Sangjin Song, Bum-Chae Choi, Dong-Hyun Cha and Kwang-Hyun Baek
Mol. BioSyst., 2011, Advance Article
DOI: 10.1039/C0MB00219D

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Diet affects cholesterol drug

Copper and zinc in the diet could impair the action of statin drugs, compounds prescribed to lower cholesterol, say US scientists.

What started as a summer project in a lab at the University of Washington in Seattle led to an unexpected find. Douglas Fowler from Stanley Fields’ group came up with a project to study the effect of combining drugs with 52 metabolites on yeast cell growth. ‘At the end of the summer, we hadn’t gathered much useful data, but I was convinced that the idea was a good one,’ says Fowler. ‘We continued with the experiments and found an unexpected result – copper and zinc impaired statin effectiveness.’ 

Statins work by inhibiting an enzyme that’s responsible for cholesterol synthesis and are used to prevent heart disease. It’s known that metabolites – molecules that break down food to provide energy in a process called metabolism – in the body can interact with drugs, but understanding how these interactions happen could enhance drug performance and reduce side effects.

The team found that with lovastatin present, the metal ions had increased the level of proteins responsible for making ergosterol, a cholesterol analogue responsible for growth in yeast. They went on to test this in cultured mammalian cells too and got the same result with cholesterol.



Copper and zinc increased levels of ergosterol and related intermediates in the presence of lovastatin

Link to journal articleSuppression of statin effectiveness by copper and zinc in yeast and human cells
Douglas M. Fowler, Sara J. Cooper, Jason J. Stephany, Natalie Hendon, Sven Nelson and Stanley Fields,
Mol. BioSyst., 2011, 7, 533, DOI: 10.1039/c0mb00166j

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Early lung cancer diagnosis

Patients with lung cancer have elevated levels of a specific protein in their blood that could be used as a biomarker for the disease, say scientists from South Korea.

Je-Yoel Cho from Kyungpook National University and colleagues saw that levels of the beta chain form of haptoglobin – a protein produced by the liver when disease is present – increased in blood samples when lung cancer cells were present.

Among cancer types, lung cancer frequently ranks at the top in both incidence and mortality, according to the World Health Organisation. The discovery of novel lung cancer specific biomarkers – substances in the blood whose levels indicate the presence and extent of the disease -is important for early detection. Current techniques to detect cancer aren’t able to give an early diagnosis.
Read more on this story

Link to journal article
The Haptoglobin chain as a supportive biomarker for human lung cancers
Sung-Min Kang, Hye-Jin Sung, Jung-Mo Ahn, Jae-Yong Park, Soo-Youn Lee, Choon-Sik Park and Je-Yoel Cho
Mol. BioSyst., 2011, DOI: 10.1039/c0mb00242a

High levels of the beta chain form of haptoglobin - a protein produced when disease is present - could be an indicator of lung cancer. (C) Nature

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DNA vaccine induced autoimmune disease

Safety concerns over the use of a DNA vaccine have been raised by Chinese scientists after they observed that it induced autoimmune disease in mice.

DNA vaccines are genetically engineered parts of virus DNA that are injected into the body to boost the immune system’s response to viral, bacterial and parasitic pathogens. Cells in the body convert the DNA into proteins that are recognised as foreign by the immune system, which triggers a response. In conventional vaccines, weakened or killed forms of the virus are injected. DNA vaccines eliminate the risk of infection associated with conventional vaccines, are extremely stable and can provide long-lived immune responses.

However, Shuhan Sun and his team from the Second Military Medical University, Shanghai, were testing mice for reactions to a DNA vaccine called pcDNA3-b1. They noticed that the mice developed symptoms of vitiligo – a skin pigmentation disorder where patches of skin lose colour – within six weeks of a third immunisation.

Mice developed vitiligo symptoms within six weeks of a third immunisation

Click here to read the full story

Link to journal article
Down-regulation of Prdx6 contributes to DNA vaccine induced vitiligo in mice
Qi Zhou, Fang Wang, Yi Zhang, Fu Yang, Yue Wang and Shuhan Sun, Mol. BioSyst., 2011
DOI: 10.1039/c0mb00181c

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The best thing since sliced bread for coeliac sufferers

Wheat with lower numbers of antigens could aid the disease

It may be possible to prevent coeliac disease by developing new types of wheat, claim Dutch Scientists who have carried out an in-depth sutdy of the genetic make up of a wide variety of wheats.

Coeliac disease is characterised by inflammation of the small intestine caused by intolerance to gluten found in wheat, rye and barley. It is an autoimmune disorder that is triggered when part of the antigen, known as an epitope, is recognised by white blood cells, causing an immune response. At present, the only treatment for this disease is a strict adherence to a gluten free diet. However, a team led by Hetty van den Broeck at Wageningen University and Research Centre in the Netherlands thinks that their research could contribute to the development of safer foods for coeliac sufferers.

Read the full story here

Link to journal article
In search of tetraploid wheat accessions reduced in celiac disease-related gluten epitopes
Hetty van den Broeck, Chen Hongbing, Xavier Lacaze, Jean-Claude Dusautoir, Ludovicus Gilissen, Marinus Smulders and Ingrid van der Meer, Mol. BioSyst., 2010
DOI: 10.1039/c0mb00046a

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Interview: Rising research

Charles Boone talks to Laura Howes about yeast, Canada and hockey 


Charles Boone is a professor at the University of Toronto, Canada. His research focuses on developing an automated approach for genetic analysis in yeast. This work has enabled the mapping of genetic networks on a large-scale and the determination of the function of all genes in a yeast model system. The function of many yeast genes is conserved in humans and this work has the potential for discovery of therapeutic drug targets. He is the chair of the
Molecular BioSystems editorial board. 


When did you decide you wanted to be a scientist?

I really liked doing science, and when I went to university I tried to get summer jobs in science. But the reality is I just loved doing research. Basic science was the fun part – figuring out how life works. When I go to hang out with my hockey team, they all wish that they were professors. At one level or another, they all do cool things too but they realise that the world of science gives you a lot of freedom and nowadays there’s a worldly aspect to it. But I didn’t know that when I started, so the bottom line is that science was interesting and something I really liked.

You started as a chemist, how did that come about and how did you then move to biology?
When I went to university I decided to study things I’m not very good at to learn more, so I studied Maths and Chemistry. I’m not a mathematician but by the end of my math course I was in classes with the geniuses. They’d be reading a book in class and I’d be trying to figure out what fuzzy logic was. I really liked chemistry but I’m like those guys that were looking for the chemical basis of life. Once I’d seen what you can do with microbiology, I thought it was really exciting so even though we didn’t have much of that at our university at the time, once I read about it I had no problem switching over straight away.

I know several people who’ve done the move from chemistry to biology, I think the biology to chemistry switch is probably more difficult?
There’s probably some problems making the shift either way. I don’t have the best grounding in some bits of biology and in some of the breadth of biology I’d like. But I’d agree that generally biologists don’t shift to being mathematicians or chemists. Chemistry is a major foundation of almost all sciences so that may make it easier.

Your work is in yeast genomics, why did you choose to research this topic?
Yeast is a major model system. I went into it by chance, because going from chemistry to biology I had to find someone to take me into their lab as most of them were sceptical that this chemist could do biology. But I have to admit that when I started working on yeast I realised that it’s an almost perfect organism for a transition from chemistry to biology because you can do almost anything with yeast. And it’s so simple – it’s a single cell so you don’t have to worry about development, at least in a major way (there are developmental programs) and you don’t have to worry about different tissues.

Can you tell us more about what you do in your lab?
There is a fairly large community working in yeast molecular genetics and genomics – about a thousand labs around the world. And there’s an incredible database called the sacaromyes genome database that houses all the information. The idea is to understand how yeast works at the level of almost every nucleotide in the genome and one of the ways we do that is to delete each gene individually. This has defined 1000 of the 6000 genes to be essential in yeast – so if you delete an essential gene the yeast dies. This indicates that most genes in eukaryotic organisms are non essential and we think one of the reasons for this is that pathways in the cell are wired with many back up pathways for any individual essential process in the cell. So there are many ways to solve a particular problem that the cell may encounter and we try to decipher which pathways are working together to solve essential functions and come up with a wiring diagram for the cell.

To do this we have identified all possible double mutants of yeast – which comes to the order of 18 million. We’ve developed a system that we call synthetic genetic array analysis that allows you to take a gene and either delete it if it is non essential or make a partially functional version if it is essential. Then make all possible double mutants with that gene and score if the mutant dies or has a fitness phenotype than is worse than we’d expect by combining the two single mutations, so it’s quantitative.

We call that a genetic interaction – so we’re scoring genetic interactions and have come up with our genetic interaction map. We hope to link each gene to those of related function and sort all the genes in a cell into clusters that work together and thereby provide a global view of how the cell is wired functionally.

Million dollar question – why do we care about yeast genetics?
Because it is a fundamental eukaryotic cell and if we can understand how it works we’ll have a much better understanding of how human cells or higher order cells in a eukaryotic organism work and then the genetic network problem is important because it is a model for the genotype to phenotype problem where if you sequence an individual and you know their variations, which combinations of mutations or alleles of genes control pathways and lead to inherited phenotypes. And no-one knows how to solve that problem beyond just the single gene.

What would you be if you weren’t a scientist?
There are two things I think I would like to be. One is an explorer, but it’s such a drag that the world’s been figured out by all those great British explorers because that would have been fun. And being a hockey player would have been way up on the list but maybe not as realistic as being a scientist. But I think the science path I took is related to exploring because it’s a great avenue for coming up with dreams and going out and trying to find them.

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