Related Experiment Video

Updated: Jul 10, 2026

Single Cell Measurements of Vacuolar Rupture Caused by Intracellular Pathogens
10:39

Single Cell Measurements of Vacuolar Rupture Caused by Intracellular Pathogens

Published on: June 12, 2013

Enterobacterial common antigen integrity is a checkpoint for flagellar biogenesis in Serratia marcescens

María E Castelli1, Griselda V Fedrigo, Ana L Clementín

  • 1Instituto de Biología Molecular y Celular de Rosario, Consejo Nacional de Investigaciones Científicas y Técnicas, Departamento de Microbiología, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Argentina.

Journal of Bacteriology
|November 6, 2007
PubMed

Insights

Enterobacterial common antigen (ECA) biosynthesis in Serratia marcescens is crucial for flagellar assembly and motility. Impaired ECA production down-regulates flagellar gene expression, affecting bacterial movement.

Area of Science:

  • Microbiology
  • Bacterial Pathogenesis
  • Molecular Biology

Background:

  • Serratia marcescens is an opportunistic pathogen found in various environments.
  • PhlA phospholipase is an extracellular factor secreted via the flagellar apparatus.
  • The regulation linking PhlA and flagellar expression requires further investigation.

Purpose of the Study:

  • To elucidate the regulatory mechanism coupling PhlA and flagellar gene expression in S. marcescens.
  • To identify genetic factors influencing both PhlA secretion and flagellar assembly.

Main Methods:

  • Generalized insertional mutagenesis was employed to screen for PhlA-deficient mutants.
  • Mutant strains were analyzed for defects in enterobacterial common antigen (ECA) assembly.
  • Motility assays (swimming and swarming), microscopy, and flagellin immunodetection were performed.
  • Gene expression analysis focused on the flhDC transcriptional regulator.

Main Results:

  • Mutations in the wec cluster, affecting ECA assembly, led to inhibited PhlA expression.
  • These ECA-deficient strains exhibited severely impaired motility due to reduced flagellum expression.
  • Down-regulation of flhDC expression was identified as the cause of the tắt transcriptional cascade for flagellar assembly.

Conclusions:

  • Enterobacterial common antigen (ECA) biosynthesis is essential for regulating flagellar gene expression in S. marcescens.
  • ECA production is a prerequisite for the proper functioning of the flagellar regulon.
  • This study reveals a novel physiological role for ECA in coordinating bacterial motility and virulence factor expression.

More Related Videos

Amikacin Protection Assay for Quantification and Visualization of Escherichia coli Cell Invasion09:22

Amikacin Protection Assay for Quantification and Visualization of Escherichia coli Cell Invasion

Published on: July 3, 2026

Related Concept Videos

Regulation of Bacterial Virulence01:28

Regulation of Bacterial Virulence

Pathogenic bacteria employ a range of regulatory mechanisms to modulate the expression of virulence genes in response to environmental and host-derived signals. These mechanisms ensure that virulence factors are expressed only under favorable conditions, thereby optimizing infection and survival strategies.Mechanisms of Virulence RegulationKey regulatory strategies include:Two-Component Systems: These consist of a membrane-bound sensor kinase and a cytoplasmic response regulator. Environmental...
Bacterial Gastroenteritis01:18

Bacterial Gastroenteritis

Bacterial gastroenteritis, characterized by diarrhea, abdominal cramps, and vomiting, is often caused by ingestion of contaminated food or water and is frequently associated with pathogenic Escherichia coli strains. These microbes exploit two principal mechanisms to inflict disease.Shiga toxin–producing E. coli, also referred to as STEC—notably O157:H7—release Shiga toxins that target ribosomes, blocking protein synthesis. The B subunit of the toxin binds the host glycolipid receptor...
Adherens Junctions01:24

Adherens Junctions

Strong contact points between adjacent cells anchor them to each other, forming tissues. Such anchoring junctions are of two types –  adherens junctions and desmosomes. Adherens junctions are abundant in tissues such as  epithelium and endothelium, forming a continuous zone of adhesion called the adhesion belt. In other tissues, such as  heart muscle, they appear as clusters, linking the cells to produce coordinated heart muscle contraction.
Adherens Junctions are Dynamic
The endothelial cells...
Fimbriae, Pili, and Axial Filaments01:28

Fimbriae, Pili, and Axial Filaments

Fimbriae and pili are specialized bacterial surface structures that play pivotal roles in adhesion, genetic exchange, and motility. Composed primarily of pilin protein, these hairlike appendages are crucial for bacterial survival and pathogenicity in various environments.Fimbriae: Adhesion and PathogenicityFimbriae are fine, filamentous structures measuring 2–10 nanometers in diameter and are densely distributed on the bacterial cell surface. They facilitate bacterial adhesion to abiotic...
Flagella and Motility in Bacteria01:18

Flagella and Motility in Bacteria

Flagella are specialized, thread-like structures that extend from a bacteria's cell envelope. They play a crucial role in motility and chemotaxis. Their structural organization and functioning exemplify sophisticated biological engineering, enabling bacterial survival and adaptability in diverse environments.Structure of the FlagellumA bacterial flagellum consists of three key components: the filament, the hook, and basal body. The filament, a long, helical structure composed of repeating...
Formation of Lipopolysaccharides01:19

Formation of Lipopolysaccharides

Lipopolysaccharides (LPS) are crucial components of the outer membrane of Gram-negative bacteria, serving both structural and functional roles. It contributes to membrane stability and protects bacteria from host immune responses. LPS is composed of three major regions—lipid A, a core oligosaccharide, and an O antigen. The biosynthesis and assembly of LPS involve a highly coordinated set of enzymatic reactions and transport mechanisms. Additionally, LPS is recognized as an endotoxin, triggering...