Related Experiment Video
Updated: May 7, 2026

Studying Oxidative Stress Caused by the Mitis Group Streptococci in Caenorhabditis elegans
Published on: March 23, 2019
Exopolysaccharides from Sinorhizobium meliloti can protect against H2O2-dependent damage
Alisa P Lehman1, Sharon R Long
1Department of Biology, Stanford University, Stanford, California, USA.
Abstract:
Sinorhizobium meliloti requires exopolysaccharides in order to form a successful nitrogen-fixing symbiosis with Medicago species. Additionally, during early stages of symbiosis, S. meliloti is presented with an oxidative burst that must be overcome. Levels of production of the exopolysaccharides succinoglycan (EPS-I) and galactoglucan (EPS-II) were found to correlate positively with survival in hydrogen peroxide (H2O2). H2O2 damage is dependent on the presence of iron and is mitigated when EPS-I and EPS-II mutants are cocultured with cells expressing either exopolysaccharide. Purified EPS-I is able to decrease in vitro levels of H2O2, and this activity is specific to the symbiotically active low-molecular-weight form of EPS-I. This suggests a potential protective function of exopolysaccharides against H2O2 during early symbiosis.
More Related Videos
20:01Single-plant, Sterile Microcosms for Nodulation and Growth of the Legume Plant Medicago truncatula with the Rhizobial Symbiont Sinorhizobium meliloti
Published on: October 1, 2013
05:51Evaluating Leaf Responses to Microbial Secondary Metabolites Using A High-Throughput Format
Published on: December 5, 2025
Related Concept Videos
Archaeal Cell Wall
Protection of Alcohols
Protection
It defines a protecting group as the masking agent to make the more reactive species inert to a given set of conditions. This concept is depicted via the illustration of liquid flow through different outlets in an assembly of pipes. The analogy helps to understand the role...
Biosynthesis of Lipids
Gene Regulation in Microbial Communities: Quorum Sensing
Responses to Salt Stress
Microbe-Plant Interactions