Biology articles
The Golden Goose Is Awarded
Salmonella Strain Spreads Alongside HIV
Fair Flu Viruses Closely Matched
Creative Emulsification
Inflammation for Regeneration
Editor's choice in microbiology
Debate Over Stem Cell Effectiveness
Editor's choice in molecular biology
Telomeres Affect Gene Expression
Re-sensitizing Resistant Bacteria
Vitamin C Slays TB Bacteria
Plant scientists, innovators
The First Plant Interactome
Plant RNAs Found in Mammals
Opinion: Beyond the Model
Sweet and Sour Science
Plant RNA Paper Questioned
Flower Barcodes
Microbial Perfume
How Plants Feel
New Databases Harvest a Rich Bounty of Information on Crop Plant Metabolism
Carnegie Institution for Science Receives Grand Challenges Explorations Grant
Genetically engineered trees could help restore devastated American chestnut
Evolution coup: study reveals how plants protect their genes
  Editor's choice in microbiology
Bacteria can form multicellular biofilms, which are glued together by an extracellular matrix. Wrinkles in the film—large enough to see with the naked eye—help to provide protection from penetration by water and gases and appear to help the colony ward off antibiotics. The physical forces shaping these 3-D structures were unknown, but Gürol Süel of the University of California at San Diego and his colleagues now show that localized cell death appears to facilitate the formation of wrinkles. Kenneth Bayles, a professor at the University of Nebraska Medical Center, who was not part of the study, says cell death in bacterial colonies has been underappreciated, and the findings show “there is a very important role for cell death in [biofilm] development.”

Süel’s group tracked the death of Bacillus subtilis cells during the growth of a biofilm using a cell death reporter called Sytox Green. “There’s really a pattern of cell death that you see,” says Süel. In cross sections of the biofilm, the researchers observed that cell death occurred at the base of the humps and dead cells became folded inside the bottoms of wrinkles. Using time-lapse microscopy, they found that cells began to die off before the formation of the folds, suggesting that the pattern of bacterial death might drive wrinkle formation.

Süel’s group then seeded the starting bacterial culture with fluorescent beads that get pushed in the direction of cell migration—like plankton floating in a current—enabling the team to track the movements of cells as the biofilm developed. The beads’ trajectories indicated that cells migrated to the point where the biofilm would buckle to form a wrinkle, and that these sites of convergence overlapped with areas of cell death. Because cell death occurs before cells begin to congregate upon that spot, Süel and his colleagues concluded that the elimination of these bacteria bolsters wrinkling.

As Süel explains it, the extracellular matrix restricts the movements of cells as the biofilm grows, resulting in a cellular squeeze. “There’s no release for the mechanical pressure. Ultimately, you have these local areas of death, and when they happen, they provide an outlet for those forces,” he says. One puzzling aspect of the process, Süel says, is how cells communicate where the regions of death are to occur.

Bayles says the findings should encourage scientists to think of bacteria not as independent, single-celled organisms, but as part of multicellular units. “When you start thinking about it that way,” he says, “it sort of makes sense that there’s a subpopulation that’s sacrificed for the whole of the organism.”
Plants Put Limit on Ice Ages
Carnegie donates landmark clones to biology
Plants on Steroids: Key Missing Link Discovered
Gene Function Discovery: Guilt by Association
Cracking the Plant-Cell Membrane Code
Private Support Helps Public Plant Research
Scientists Watch Cell-Shape Process for First Time
How plants choose their mates
Mastermind Steroid Found in Plants
Unlocking the secrets of a plant’s light sensitivity
Nailing down a crucial plant signaling system
What makes a plant a plant?
New component of a plant steroid-activated pathway discovered
Big Boost to Plant Research
The Heart of the Plant
New tool offers unprecedented access for root studies
Steroids control gas exchange in plants
Plant toughness: Key to cracking biofuels?
Amoeba may offer key clue to photosynthetic evolution
The future of plant science – a technology perspective
Plant research funding crucial for the future
Wolf B. Frommer Receives Bogorad Award for Excellence in Plant Biology
Lighting up the plant hormone “command system”
Plant organ development breakthrough
Breakthrough: How salt stops plant growth
New Cancer Diagnostic Technique Debuts
Plant Science Could Ease Global Food and Fuel Demands
Have you had your cereal today?
Researchers close in on engineering recognizable, drug-free Cannabis plant
UC Riverside Researchers Develop Genetic Map for Cowpea
New research shows how mobile DNA survives—and thrives—in plants, animals
Cucumber Genome Published
Structural study at EMBL reveals how plants respond to water shortages
“Safety Valve” Protects Photosynthesis from Too Much Light
Weeds Could Help To Feed The World
Antagonistic Genes Control Rice Growth
Making New Enzymes to Engineer Plants for Biofuel Production
Green Plant Transport Mystery Solved
Gene Discovery To Increase Biomass Needed For Green Fuel
Are genes our destiny?
New African cassava resists devastating viruses
Species richness and genetic diversity do not go hand in hand in alpine plants
Scientists discover how cancer may take hold
Green algae—the nexus of plant/animal ancestry
New Twist on Life’s Power Source
Controlling a sea of information
Plant Steroids Offer New Paradigm for How Hormones Work
Future of biology rests in harnessing data avalanche
Carnegie’s Arthur Grossman Receives Gilbert Morgan Smith Medal
Plant Scientists Participate in DOE Energy Frontier Research Center
Advance in understanding cellulose synthesis
Midget Plant Gets Makeover