Researchers at the University of California, Riverside have unlocked the molecular give and take that allows cells in thin structures such as leaves to develop in a jigsaw-like pattern, providing the leaf a surprising degree of strength. The findings were published in today's edition of the journal Cell.

Foreign species, such as zebra mussels and carp, are invading the Great Lakes and changing the ecology of this vital ecosystem. A study from McMaster University published in the March issue of the Journal of Great Lakes Research suggests that for the round goby, a recently introduced fish species, their ability to wrest territory from native fish plays a key role in their dominance of the Great Lakes.

An article in Journal of Applied Microbiology investigates how bacteria respond when they are subjected to environmental alterations, such as those of space stations, which feature lowered effects of gravity.

A new tumor-suppressor gene has been discovered by a team of researchers at Penn State, which also has discovered how the gene works with another tumor suppressor to control tissue growth. The team's genetic and biochemical studies will be published in the 11 March 2005 issue of the journal Cell. "This discovery extends our understanding of how tissue growth is controlled both during normal development and during the formation of tumors, and it raises the possibility that the function of this gene may have important implications for the understanding and treatment of human cancers," says research leader Zhi-Chun Lai, associate professor of biology, biochemistry, and molecular biology.

A group of scientists at The Scripps Research Institute is reporting a discovery that sheds light on an area of research fundamental to everything from the normal processes that govern the everyday life of human cells to the aberrant mechanisms that underlie many diseases, including cancer and septic shock.

The discovery concerns tiny fragments of RNA known as microRNA and their relationship to the genetic transcripts known as messenger RNA (mRNA).

All genes expressed in the human body must be transcribed as mRNA before they can be translated into proteins, and the stability of these mRNA transcripts is essential for control of genetic expression.

In the latest issue of the journal Cell, the Scripps Research team, led by Immunology Professor Jiahuai Han, describes how genetic control can be exerted in living cells through microRNA's action in conjunction with several different proteins.

The chromosomes of mammals, including humans, contain regions that are particularly prone to breaking under conditions of stress and in cancer. Now, new research by geneticists at Duke University Medical Center finds that yeast cells also contain such weak links in DNA and begins to reveal the molecular characteristics of these links that might help to explain them.

The findings, published in the March 11, 2005, issue of Cell, suggest that yeast may offer a useful model system for studying the fundamental properties of so-called DNA fragile sites, providing new insight into the chromosomal instability found in cancer cells, said the researchers.

After infecting a susceptible cell, the human immunodeficiency virus hijacks that cell's normal machinery to produce carbon copies of itself. New HIV particles roll off the cellular assembly lines, burst like bubbles out of the cell, and float off to invade other cellular factories. Vanderbilt University Medical Center investigators have now identified an early step in HIV particle assembly. The findings, published March 11 in Cell, could lead to new drugs that combat HIV infection by shutting down the virus's assembly lines.

A gene that, in different variants, increases or decreases the level of atherosclerosis has been identified in mice. The corresponding human gene has been shown to play a role in the development of myocardial infarction.

The results of the study is published this week on Nature Genetics Online.

Discoveries by a research team from Maine could help to settle a long-standing debate in genetics.

Some genes are seemingly inseparable in nature; they form a haplotype-a set of genes inherited as a unit. Some researchers support the notion that mapping haplotypes may be more significant than mapping the genome. The haplotype map could allow researchers to look for a single variation in the complex genetic code and know all the variations associated with it, since all are part of the same haplotype.

The Maine research group challenges that proposal, demonstrating that genes within a haplotype function independently. The group included Dr. Antonio Planchart of the Mount Desert Island Biological Laboratory and the College of the Atlantic, Bates College undergraduate Jennifer Reynolds, and Dr. John Schimenti, adjunct senior staff scientist at The Jackson Laboratory.