Genetics & Molecular Biology
Previously unrelated disorders which all cause complex defects in brain development and function are linked by a common underlying mechanism. Rett syndrome (RTT), Cornelia de Lange syndrome (CdLS), Alpha-Thalassemia mental Retardation, and X-linked syndrome (ATR-X) have each been linked with distinct abnormalities in chromatin, the spools of proteins and DNA that make up chromosomes and control how genetic information is read in a cell.
The new research, appearing in Developmental Cell, helps to explain why these different chromatin abnormalities all interfere with proper gene expression patterns necessary for normal development and mature brain function.
When asked to justify the research I do, I always struggle a little to explain my dissatisfaction with the traditional descriptive, non-quantitative explanations of molecular biological systems. As a glance at a classic molecular cell biology textbook
will easily demonstrate, molecular biologists have been tremendously successful with verbal or semi-quantitative explanations of what goes on inside the cell. And in any case, the complexity of the cell is extremely daunting for the would-be theoretical biologist.
Researchers from the University of California, San Diego have discovered the origin of strains of the human immunodeficiency virus (HIV) among men who have sex with men. The team says the results are important because knowing the mechanisms by which HIV uses human sex to spread is essential to stopping the HIV epidemic.
It is known that most HIV infections worldwide result from exposure to the HIV virus in semen, made up of seminal cells and the fluid around these calls, called seminal plasma. HIV virus particles contain RNA and exist in the plasma, while infected seminal cells contain HIV DNA.
Arizona State University researchers have developed the first versatile DNA reader that can discriminate between DNA's four core chemical components, the key to unlocking the vital code behind human heredity and health. If the process can be perfected, DNA sequencing could be performed much faster than current technology, and at a fraction of the cost.
There is an apocryphal story about a graduate mathematics student at the University of Virginia studying the properties of certain mathematical objects. In his fifth year some killjoy bastard elsewhere published a paper proving that there are no such mathematical objects. He dropped out of the program, and I never did hear where he is today. He's probably making my cappuccino right now.
Walter Fontana, a Professor of Systems Biology at Harvard, reflects on models in biology:
Models will play a central role in the representation, storage, manipulation, and transmission of knowledge in systems biology. Models that are capable of fulfilling all these purposes will likely differ from the familiar styles deployed with great success in the physical sciences. "Classical" flavors of models may be viewed on a continuum between two major types:
Models that are of heuristic nature.
Johns Hopkins scientists have discovered that common but hard-to-see sugar switches play an important role in cell division. Because these previously unrecognized sugar switches are so abundant and potential targets of manipulation by drugs, the discovery of their role has implications for new treatments for a number of diseases, including cancer, the scientists say.
Scientists have long known that sperm's activity level depends on their internal pH. And now researchers writing in Cell say they have found the channel that allows the tiny cells to rid themselves of protons. Once in the female reproductive tract, that proton release changes their internal environment from acidic to alkaline and begins their race to the finish line. The findings offer new insight into a critical event in human fertilization and may lead to new ways of controlling male fertility.
"The concentration of protons inside the [sperm] cell is 1,000 times higher than outside," said Yuriy Kirichok of the University of California, San Francisco. "If you just open a pore, protons will go outside. We identify the molecule that lets them out."
A new study published today in Nature suggests that approximately seven in every thousand morbidly obese people are missing a section of their DNA containing approximately 30 genes, which may be having a dramatic effect on their weight.
Researchers identified the missing genes in teenagers and adults who had learning difficulties or delayed development. They found 31 people who had nearly identical 'deletions' in one copy of their DNA. All of the adults with this genetic change had a BMI of over 30, which means they were obese.
The 'primordial soup' theory--which posits that early life began in a soup of organic molecules before evolving out of the oceans millions of years later--is fatally flawed, according to researchers writing in BioEssays. Instead the authors claim it was the Earth's chemical energy, from hydrothermal vents on the ocean floor, which kick-started early life.
In rejecting the soup theory the team turned to the Earth's chemistry to identify the energy source which could power the first primitive predecessors of living organisms: geochemical gradients across a honeycomb of microscopic natural caverns at hydrothermal vents. These
catalytic cells generated lipids, proteins and nucleotides giving rise to the first true cells.