Biotechwiz

News,Views & Insights on Biotechnology

Browsing Posts published in August, 2010

Scientists at Liverpool, University of Bristol and the John Innes centre have released the draft sequence of the entire wheat genome. They were working in collaboration with the International Wheat Genome Consortium. This research has been funded by the Biotechnology and Biological Sciences Research Council. The work was carried out at the University’s Centre for Genomic Research, which is home to 5 next generation analyzers that can read sequences 100 times faster than those used to sequence the human genome!

This work has been received with great excitement and is expected to help wheat breeders to be able to select for strains of Wheat having desired characteristics. The reference variety used for the sequencing is the Chinese Spring Wheat (Triticum aestivum L. cv Chinese Spring) Strain. The availability of this sequence is expected to highlight natural Genetic variants between wheat types to help breeding programs. Wheat breeders have had precious little genetic information in the past to be able to make a choice as to the variety of wheat to be selected.

 

Wheat: One of the most important Food Crops in the World

Wheat: One of the most important Food Crops in the World

 

The sheer size of the wheat genome has been daunting in terms of whole genome sequencing. The Wheat genome is about five times the size of the human genome and hence was considered close to impossible to sequence. In Comparison to other important crop plants such as Soyabean and Rice, the difficulty of working with such a large genome has left wheat lagging behind in the race of genome sequencing. However, using advanced sequencing techniques employed by Roche’s 454 sequencers, the effort has managed to cover about 95% of the known wheat genes. The results of the study are now available for public use via Genbank, EMBL and CerealsDB. Nevertheless, there are those who warn that the gene map is far from complete and that the first high quality complete map data will be available only within five years. The full sequenced genome requires further read-throughs, assembly of the data into chromosomes and significant work to fully annotate the sequence data.

According to Dr. Neil Hall of the University of Bristol, within the next 40 years the food production should be increased by at 50 % of the current value. This can only be achieved if we are able to produce wheat strains resistant to drought conditions, pesticides and salinity. Traditional methods require time consuming crosses and painstaking selection of desired characteristics sometimes after several generations. The use of genetic techniques would hopefully reduce the time frame and enable the breeder to efficiently select desired traits. These traits may include disease resistance, the ability to grow under extremes of whether and soil characteristics, & producing increased yields with minimum inputs in terms of fertilizers and other growth factors.

Wheat is one of the most important food crops around the world (though most of the wheat produces is what is known as red wheat and not the one that has been used for the study) with an estimated annual production close to 550 million tonnes. Mike Bevan of the John Innes institute has placed emphasis on the importance of the study in the light of a sharp spike in the international prices of wheat following a ban on wheat exports by Russia (due to droughts and wildfires) and the overall decrease in wheat production by countries such as Pakistan and China due to heavy rains and floods.

The wheat genome holds secrets aplenty waiting to be unlocked. We are racing against time as far as food security is concerned and any step forward is all for the best. We are waiting eagerly for the promise to be fulfilled and for the time when wheat breeders can easily and quickly select varieties that will pave the way for the next revolution. Countries like India that are struggling to meet the demands of burgeoning populations and where cultivable land is at a premium are sure to benefit from this research.

 

An Interview with Dr. Krishanu Saha from the Whitehead Institute of Biomedical Research: On the invention of a new Synthetic Surface for the Cultivation of Human Stem cells for up to three months.

Scientists at MIT have developed a novel synthetic surface for the cultivation of human stem cells. The research team, led by Professors Robert Langer, Rudolf Jaenisch and Daniel G. Anderson, describes the new material in the Aug. 22 issue of Nature Materials. First authors of the paper are postdoctoral associates Krishanu Saha and Ying Mei. The new material was singled out of almost 500 polymers designed during the course of the study, and was found to be optimal after analysing  several chemical and physical properties of surfaces, including roughness, stiffness, and affinity for water that might play a role in stem cell growth. The new surface not only enabled Stem Cells to be grown for up to three months but also enabled harvesting of cells in the millions. Both of these attributes are very important to researchers as the in vitro culture of human Stem cells is fraught with difficulty. The surface also enables clonal growth of a stem cell allowing for easy selection of a particular cell with attributes of interest. As Researchers laud this important invention, Biotechwiz is proud to present an exclusive interview with Dr. Krishanu Saha, one of the authors of this seminal work. An excerpt of the interview is presented below:

Dr. Krishanu Saha

Dr. Krishanu Saha

Biotechwiz: Why did you feel the need to develop a new material for the growth of stem cells?

Dr. Krishanu Saha: When we started this work, there were only a handful of culturing materials that were used to grow human embryonic stem cells. Most of these materials included components from animal sources. These animal-derived components are problematic for any cell therapy applications envisioned with these cells, because such components utilized during cell culture can increase the risk of immune rejection when such cells are injected into a patient.  We therefore sought to explore whether a library of synthetic polymers coated with human-derived proteins could replace and improve on the conventional methods of growing human embryonic stem cells.

We also wanted to gain more molecular insight into how human embryonic stem cells grow outside of the body. Mouse embryonic stem cells have particular properties of cell growth and genetic manipulation that make them easier to work with in the lab.  We wondered whether we could devise better culture conditions for human embryonic stem cells by systematically exploring stem cell growth on a diverse set of polymeric materials.

BW: Can you elaborate a bit on the nature of this new surface that you have developed and what is the most unique feature of your invention according to you?

Dr. Saha: The new surfaces can be synthesized entirely from standard chemicals.  They utilize a particular chemistry that was not defined before this work to interact with a human protein, Vitronectin.  The most unique feature is that it can support the long-term culture of fully dissociated human embryonic stem cells as well as the recently ‘reprogrammed’ human induced pluripotent stem cells.

BW:  How soon do you think the research you have done will be available as a commercially viable product?

Dr. Saha: This question of technology transfer is a difficult one to predict. There are already a few commercial products based on other work with novel stem cell culture materials that was just published in May. So if we extrapolate from those cases, our work could be translated into products in less than a year.  I believe the MIT technology transfer office is dedicated to ensuring that the materials get widely used.

BW:  What is the trend your future research is likely to take?

Dr. Saha: I am generally interested in combining this work with recent advances in cellular reprogramming. Cellular reprogramming can produce embryonic stem cell-like cells called induced pluripotent stem (iPS) cells from virtually any human cell source, such as a blood sample or biopsy.  I believe there is a key role of materials and engineering to play in developing these iPS cells for disease modelling and regenerative medicine applications.

BW: Can you tell us about any one hurdle that bugged you the most during your work?

Dr. Saha: Finding common patterns in the material characteristics that controlled the growth of the human embryonic stem cells was challenging.  We had hundreds of polymers with lots of data about surface chemistry, stiffness, and roughness that needed to be sorted and globally analyzed. At times, this seemed tedious, but it is part of the research process.

A lot of research depends upon making comparisons between healthy and sick individuals. And the results of these comparisons have been used to develop newer and better diagnostics, prophylactics and treatments. The current study is also pretty much based on comparison between ducks that are infected with the Bird Flu virus and those that were completely healthy. The only difference here being that the comparison involved the smell of the feaces of the two groups of ducks in question, and the ‘detectors’ of these olfactory differences were lab-trained mice!

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For all those who were waiting with bated breath for the first ever Human Embryonic stem cell (HESC) phase I clinical trials to begin, well there’s good news. On the 30th of July 2010, the US based Geron Corporation announced the FDA’s approval to its HESC based clinical trials in humans. The announcement comes after a year-long set-back to the proposed trials, after the company discovered during some of its tests that the rats treated with the stem cell line developed cysts. This set off a spate of further tests to ensure efficacy and safety of the therapy. After a year, the company seems to have effectively allayed fears of tumorigenicity and has obtained a green signal from the US FDA and will be beginning the first human trials of Human Embryonic stem cell therapy in the world.

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