New Key Mechanism in Cell Division Discovered

In every organism, cells grow and divide into two daughter cells through an orderly succession of events called "cell cycle." Cells have to complete four main processes during the cell cycle: growth (G1 and G2 phases), doubling the DNA (S phase), segregation of chromosomes (M phase, mitosis) and division (cytokinesis). In the S phase or DNA replication, the genetic material is duplicated and then during the M phase or mitosis, cells separate the duplicated chromosomes between two daughter cells. This will ensure correct inheritance of genetic information from one cell generation to the next.
Chromosomal stability
The transmission of genetic information (DNA) from parent to child (or equivalently, from cell to cell) is a fundamental question in biology. Aneuploidy, ie lack or excess of chromosomes, is a feature present in almost all human cancers and promotes tumour development. Regulation of mitosis is particularly important for maintaining chromosomal stability. For example, tumour cells are aneuploid due to defects in the segregation of chromosomes, which originate cells with more or less genetic material than usual.
However, in spite of its importance, very little is known about the output regulation of mitosis. In the article published in the Journal of Cell Science, the Cell Cycle research group at IDIBELL led by Ethel Queralt, discovers a new mechanism of regulation of mitotic exit.
Separase protein is a key component for proper chromosome segregation and the regulation of mitosis. In previous work, the group of Dr. Queralt described for the first time the involvement of Zds1 protein in mitosis. This protein cooperates with the separase to ensure correct genetic inheritance from cell to cell.
The study delves into the molecular mechanism by which this protein Zds1 regulates mitosis and contributes to the right segregation of chromosomes. In this paper there have been used the yeast Saccharomyces cerevisiae as a model organism.
Yeast is one of the most widely used model organisms to study basic processes in the cell, allowing to identify complex molecular mechanisms as the study of cell cycle in higher organisms. The application of such basic knowledge will help to develop more specific and direct treatments against various cancers.
Dr. Queralt points out that "the mechanisms of regulation of mitosis are very complex and well-known fact opens the door to specific drugs that inhibit or enable to correct this process in various diseases, especially cancer." She explains that most anticancer drugs are being implemented without knowing exactly how they work, "these are compounds that often we do not know how are working, but they do. If we follow a reverse process, ie if we start to know the activity of a protein or part of the protein, we could design specific drugs to minimize side effects." Dr. Queralt's researching is an important step in developing therapies that prevent tumour cells from replicating.

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Japanese scientists use particle accelerator to create salt-resistant rice

An unfortunate and little reported side effect of last year’s Japanese earthquake and tsunami is that thousands of acres of farmland were contaminated with seawater. Rice is a staple crop in Japan, and it requires large amounts of water to grow. The salt in seawater, however, stunts or outright kills the plant. Researchers out of Riken Nishina Centre near Tokyo have been looking at the problem, and it just so happens they have a particle accelerator laying around. You can probably see where this is going.
Researchers have been working to develop a strain of rice that can tolerate salt for a number of years, but this new method could vastly improve rice agriculture. All agriculture is about nurturing desired traits in a crop; it’s just how you go about it that ruffles some feathers. Before modern science, it was a painstaking process to selectively breed plants to express the traits that make them hardier, or better for human consumption — now we can do it faster.
Genetically modified foods are becoming commonplace as we learn more about the genomes of various plants. However, for genetic modification to work, we need to know exactly what genes to manipulate. This would be fast and effective, but genes for salt-resistance are not yet well-understood in rice. That leaves researchers with the more scattershot approach of irradiation.
Mutations naturally accumulate over time (this is evolution), but this rate is far too slow for meaningful research. Past efforts in inducing mutations have relied on X-rays or gamma radiation to cause mutations in crops, but a particle accelerator should be able to accomplish the same thing much faster. Dr. Tomoko Abe is leading the research and hopes that the particle accelerator will prove superior to traditional methods. Initial results indicate this approach can produce 10-100 times more mutations.
In her experiments, Dr. Abe exposes germinating rice seeds to a stream of carbon ions for 30 seconds. The ions are simply atoms that have been stripped of their electrons, and they do a real number on the rice’s DNA. The irradiated seeds are planted in high-salt rice paddies to see which, if any, will thrive. After bombarding 600 seeds in her particle accelerator, Dr. Abe has created 250 mutant strains that were able to grow in salt water and produce fertile seeds of their own.
If this sounds scary, don’t get too worked up. These super-mutants aren’t the end product ready for your dinner table. The next step is to replant the most successful specimens and begin sorting out the traits that make them grow so well. Some will eventually be used for crossbreeding to concentrate the best mutations in the remaining strains. The genetic information gathered could also be used in future biotech rice products.
With enough testing, Dr. Abe hopes to be able to generate an edible strain of rice in four years that can grow in a high-salt environment. If this research is a success, the effects could reach much farther than northern Japan; there are many coastal locations around the world that could benefit from a more hearty strain of salt-resistant rice.

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