News on Health & Science

Jet Lag to be History

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Scripps Research scientists say that they have determined the molecular structure of a plant photolyase protein, which is very similar  to the two proteins that control the circadian clock in humans and other mammals, moving a step closer to making jet lag history.


The researchers claim that their study has even enabled them to test how structural changes affect the function of such proteins.

“The plant photolyase structure provides a much better model to use to study how the cryptochrome proteins in the human clock function than we have ever had before,” says Dr. Kenichi Hitomi, a postdoctoral research fellow at Scripps Research.

“It’s like knowing for the first time where the engine is in a car. When you know what the most important parts of the protein are, then you can begin to figure out how it functions,” the researchers added.

Dr. Elizabeth Getzoff, professor in the Department of Molecular Biology and member of The Skaggs Institute for Chemical Biology at Scripps Research, says that understanding how these proteins work may be helpful in fixing the clock when needed.

“In addition to decoding how the clock works, a long-term goal is to develop a drug to help people who can’t reset their clock when they need to, like people who work night shifts or travel long distances. Having the three-dimensional protein is a great step forward in both of those pursuits,” she says.

Working in collaboration with researchers from Scripps Research and from other institutions, including two universities in Japan, Hitomi studied Arabidopsis thaliana, a plant native to Europe and Asia that has one of the smallest genomes of all plants.

The researchers point out that just like all other plants, this plant also contains proteins known as photolyases, which use blue light to repair DNA damage induced by ultraviolet light.

They say that humans and mammals possess a homologous protein known as cryptochrome that modulates the circadian clock.

Getzoff says: “This is an amazing, and very puzzling, family of proteins, because they do one thing in plants and quite a different thing in mammals, yet these cousins all have the same structure and need the same cofactor, or chemical compound, to become activated.”

Hitomi adds: “All of these proteins were probably originally responses to sunlight. Sunlight causes DNA damage, so plants need to repair this damage, and they also need to respond to sunlight and seasons for growth and flowering. The human clock is set by exposure to sunlight, but also by when we eat, sleep and exercise.”

Hitomi and his colleagues set about producing proteins from the Arabidopsis thaliana genes that produce two related photolyase enzymes. These genes had been cloned earlier in the laboratory of co-author Dr Takeshi Todo of Kyoto University.

The researchers moved the gene from the plant into E coli bacteria to produce a lot of the protein, and later crystallized it to determine the atomic structure by using X-ray diffraction.

The researchers then produced a variety of mutant proteins in order to test the functional structure of the enzymes.

“We can now look at things that are the same and different between human and mouse cryptochromes and plant photolyases. Our results provide a detailed, comparative framework for biological investigations of both of these proteins and their functions,” says Hitomi.

He believes that his team’s findings may form the basis of drugs that can ease jet lag and regulate drug metabolism, as well as help better understand some fascinating circadian clock disorders that have been found in mice and man.

The study has been published in The Proceedings of the National Academy of Sciences.

Sources:The Times Of India

News on Health & Science

A ray of hope for autism.

After years of research, scientists have zeroed in on the genes responsible for autism. V. Kumara Swamy reports

A five-year-long international study that looked into the genetic underpinnings of autism has zeroed in on new genes, giving hope to millions that some day a treatment for this complex brain disorder may be possible. According to current estimates, around 1.7 million people suffer from autism in India.


The preliminary results of the study, gleaned from a large sample of 1,200 families with multiple cases of autism in 19 different countries, were published in this month’s issue of Nature Genetics. More than 120 scientists from 50 institutes participated in the exercise.

The Autism Genome Project, launched way back in 2002, in its first phase assembled the largest gene “biobank” in the world. It conducted a comprehensive genome scan, announcing last month that the susceptible genes  responsible for inheriting the risk of the disease  have been identified.

Autism is a psychiatric disorder that inhibits a child’s ability to communicate and develop social relationships, resulting in slow learning and severe intellectual impairment in some cases.

The identification of the susceptible genes, say the experts, will provide an insight into the basis of the disease as well as pave the way for developing intervention methods.

The scientists had at their disposal a gene chip  technology that can rapidly look for genetic commonality in the samples collected.

The new study implicates a previously unidentified region of chromosome 11 and neurexin 1, a member of a family of genes believed to be important in neuronal contact with and communication to other parts of the body. Although there have been several genetic analyses for autism, the results have not been uniform and none has been performed on such a large scale before.

Researchers also speculate that there may be five or six major genes and as many as 30 others involved in autism. If a foetus has more of these genes, there is a higher chance of being born with autism or a more severe form of the disease.

According to Andy Shih of Autism Speaks, a New York-based organisation, the findings could have an impact in the near future. Some of the data will have immediate diagnostic impact, and the new understanding of the genetic contributors will give direction to the development of targeted treatment and intervention,  he says. Shih’s organisation is one of the funders of the current research study.

First classified as a specific disorder over 50 years ago, the incidence of autism is rising steadily, although the criteria for diagnosis have changed over time.

There have been various estimates for autism in India, but no prevalent study that can arrive at a definite figure, says Dr Shobha Srinath of the National Institute of Mental Health and Neuro Sciences (Nimhans), Bangalore. Moreover, there may be underreporting in many places owing to ignorance, she adds.

While it is estimated that one in every 500 children suffer from autism in India, in countries like the US, the problem is more acute with the figure being one in every 150 children. According to experts, the disease affects more boys than girls. In the UK, autism is said to affect one in every 100 children.

Researchers have for long suspected a genetic link to the disease, and the latest study only confirms that, says Dr J.R. Ram, consultant psychiatrist, Apollo Gleneagles Hospital, Calcutta. “The study is a breakthrough so far as understanding the problem is concerned, but because autism is such a complex disease we need to be realistic about the findings,” he adds.

Parents, it seems, are also of the same opinion.  see this study as a ray of hope, but I think we are still some distance away from any effective treatment in the form of medication,” says Indrani Basu, the parent of an autistic child and also the head of the Autism Society of West Bengal, Calcutta.
Source:The Telegraph (Kolkata,India)