Related Experiment Video
Updated: Aug 12, 2026
10:36
Visualization of UV-induced Replication Intermediates in E. coli using Two-dimensional Agarose-gel Analysis
Published on: December 21, 2010
Swarming ring patterns in bacterial colonies exposed to ultraviolet radiation
A M Delprato1, A Samadani, A Kudrolli
1Department of Physics, Clark University, Worcester, Massachusetts 01610, USA.
Physical Review Letters
|October 3, 2001
Summary
Ultraviolet radiation exposure caused Bacillus subtilis colonies to form a ring pattern. Bacteria migrated to the edge, then grew inward and outward, indicating a novel response to UV stress.
Area of Science:
- Microbiology
- Biophysics
- Mathematical Biology
Background:
- Bacillus subtilis colonies exhibit complex spatial patterns during growth.
- Environmental stressors can induce significant morphological changes in bacterial colonies.
Purpose of the Study:
- To investigate the morphological response of Bacillus subtilis colonies to ultraviolet (UV) radiation.
- To elucidate the mechanism behind UV-induced colony pattern formation.
Main Methods:
- Observation of Bacillus subtilis colony morphology after UV exposure.
- Analysis of colony growth patterns under varying conditions.
- Development of a reaction-diffusion model to simulate observed phenomena.
Main Results:
- UV radiation induced a novel ring-like morphological transition in Bacillus subtilis colonies.
- Bacteria migrated from the colony center to the edge, forming a distinct ring.
- Post-exposure growth occurred both inward and outward, ruling out nutrient depletion as the sole cause.
Conclusions:
- UV radiation triggers a unique spatial reorganization in Bacillus subtilis colonies.
- The observed pattern is likely driven by waste-limited chemotaxis initiated by UV stress.
- Reaction-diffusion modeling provides a framework for understanding this UV-induced bacterial behavior.
Related Concept Videos
01:30Bacterial Signaling
Bacterial signaling can occur within bacteria (intracellular) or between bacteria (intercellular). At times, a group of bacteria behaves like a community. To achieve this, they engage in quorum sensing, the perception of higher cell density that causes changes in gene expression. Quorum sensing involves both extracellular and intracellular signaling. The signaling cascade starts with a molecule called an autoinducer (AI). Individual bacteria produce AIs that move out of the bacterial cell...
01:35Mutations
Mutations are changes in the sequence of DNA. These changes can occur spontaneously or they can be induced by exposure to environmental factors. Mutations can be characterized in a number of different ways: whether and how they alter the amino acid sequence of the protein, whether they occur over a small or large area of DNA, and whether they occur in somatic cells or germline cells.
Chromosomal Alterations Are Large-Scale Mutations
While point mutations are changes in a single nucleotide in...
Chromosomal Alterations Are Large-Scale Mutations
While point mutations are changes in a single nucleotide in...
01:13Special Staining Techniques
Specialized staining techniques play a vital role in microbiology by enabling the visualization of specific bacterial structures that remain undetectable with standard microscopy methods. These techniques not only enhance the structural visualization of bacterial cells but also provide critical insights into their pathogenicity and classification. Additionally, they support diagnostic and research endeavors in microbiology by identifying key bacterial features.Capsule Staining for Virulence...
01:28Gene Regulation in Microbial Communities: Quorum Sensing
Quorum sensing is a mechanism of bacterial communication that enables coordinated gene expression in response to changes in population density. This facilitates collective behaviors that enhance survival, resource acquisition, and ecological adaptation. This process relies on small signaling molecules called autoinducers that accumulate as bacterial populations grow. When a critical threshold concentration of autoinducers is reached, bacterial cells collectively modify gene expression,...
01:18Other Unique Bacteria
Magnetic bacteria exhibit a directed movement called magnetotaxis, driven by structures called magnetosomes. These magnetosomes consist of chains of magnetic particles made of either magnetite (Fe₃O₄) or greigite (Fe₃S₄) and are organized in a linear conformation by a protein scaffold within invaginations of the cell membrane. The bacteria align along the north–south magnetic field lines, much like a compass needle. They are typically microaerophilic or anaerobic and are commonly found near the...