Genetics & Molecular Biology

A group of University of Utah scientists say they developed a "molecular condom" that could help protect women against AIDS in Africa and other impoverished areas.

It's a vaginal gel that turns semisolid in the presence of semen, trapping AIDS virus particles in a microscopic mesh so they can't infect vaginal cells.

A study testing the behavior of the new gel and showing how it traps AIDS-causing HIV particles will be published online later this week in the journal Advanced Functional Materials.
The sex hormone estrogen tempers the killing activity of immune cells called cytotoxic T cells (CTLs), which are known to attack tumor cells and cells infected by viruses.

Estrogen plays a critical role in the regulation of growth and the development of cells and is also crucial for cell-type-specific gene expression in various tissues. Deregulation of this system results in breast and ovarian cancer.  The key player in this process is a cytotoxic T cell molecule known as EBAG9.

Breast and ovarian tumors are treated with drugs such as tamoxifen. Researchers suggest that this drug inhibits tumor growth by blocking the estrogen receptors of the tumor cells. However, up to now it has been unclear what effect this inhibition has on the immune system. 
We may not like to admit it, human beings engage in "like with like" mating, what population geneticists call assortative mating.  Individuals are more likely to mate with other individuals[1] with characteristics like their own (i.e., Brangelina).  Humans practice assortative mating based on many characteristics, such as height, IQ, skin color, social status, and religion.  And, according to this Hot or NotTM study, humans also practice assortative dating based on looks
Tangential Science: it's not necessarily science, but it's still funny.

Researchers at the University of California Riverside (UCR) have developed a new mid-season maturing variety of tangerine. They call it DaisySL, for for Daisy seedless. It is made from an irradiated bud of the seedy diploid mandarin cultivar 'Daisy,' that is a hybrid of the mandarins Fortune and Fremont

Supervised by staff scientist Timothy Williams, the planting of the trees and performed evaluations and selections of promising varieties were meticulously monitored. It was 'DaisySL' that had the right characteristics he and Mikeal Roose, a professor of genetics in the Department of Botany and Plant Sciences at UCR, were looking for in a new variety: beautiful appearance, exceptional flavor, and hardly any seeds.

Our cells are controlled by billions of molecular 'switches' that react to our environment.  All creatures, from bacteria to humans, must monitor their environments in order to survive. They do so with biomolecular switches, made from RNA or proteins. For example, in our sinuses, there are receptor proteins that can detect different odors. Some of those scents warn us of danger; others tell us that food is nearby.

UC Santa Barbara researchers say they have developed a theory that explains how these molecules work and their findings may significantly help efforts to build biologically based sensors for the detection of chemicals ranging from drugs to explosives to disease markers.
Scientists say they have discovered a unique 'DNA signature' in human sperm, which may act as a key that unlocks an egg's fertility and triggers new life. 

Drs David Miller and David Iles from the University of Leeds, in collaboration with Dr Martin Brinkworth at the University of Bradford, say they have found that sperm writes a DNA signature that can only be recognized by an egg from the same species. This enables fertilization and may even explain how a species develops its own unique genetic identity. 

Without the right 'key', successful fertilization either cannot occur, or if it does, development will not proceed normally. Notably, disturbances in human sperm DNA packaging are known to cause male infertility and pregnancy failures. 
Scientists in New York and North Carolina say they have assembled the first functioning prototype of an artificial Golgi organelle, a key structure inside cells which helps process and package hormones, enzymes, and other substances that allow the body to function normally.

They say their 'lab-on-a-chip' device could lead to a faster and safer method for producing heparin, the widely used anticoagulant or blood thinner, the researchers note. The study is published in the Journal of the American Chemical Society

The Golgi organelle is named for Camillo Golgi, the Italian scientist and Nobel Prize winner who discovered the structure in 1898.
Genetic disease such as leukemia are a big target in 21st century science thanks to advancements in our understanding of how the body works.  

Some of our treatments, like chemotherapy, are rather brute force in their solution.   Now scientists from the Université de Montréal and McGill University say they have re-engineered a human enzyme, a protein that accelerates chemical reactions within the human body, to become highly resistant to harmful agents like chemotherapy.
Millions of children, as many as 2% of all births in the U.S. and Europe, have been born to couples with fertility problems through assisted reproductive techniques such as in vitro fertilization (IVF). Because it is a newer field, relatively little research has been conducted to evaluate the long term effects of assisted reproductive techniques. 

Research presented at the Annual Meeting of the Society for the Study of Ingestive Behavior (SSIB) says that assisted reproductive techniques alter the expression of genes that are important for metabolism and the transport of nutrients in the placenta of mice.