Related Experiment Video

Updated: May 23, 2026

High-throughput Assay to Phenotype Salmonella enterica Typhimurium Association, Invasion, and Replication in Macrophages
11:10

High-throughput Assay to Phenotype Salmonella enterica Typhimurium Association, Invasion, and Replication in Macrophages

Published on: August 11, 2014

Acidic pH induced STM1485 gene is essential for intracellular replication of Salmonella

Uday Sankar Allam1, M Gopala Krishna, Minakshi Sen

  • 1Department of Microbiology, Centre for Infectious Disease Research and Biosafety Laboratories, Indian Institute of Science, Bangalore, India.

Virulence
|March 31, 2012
PubMed

Insights

The Salmonella gene STM1485, induced by acidic pH, is vital for bacterial survival within host cells. Its absence impairs Salmonella

Area of Science:

  • Microbiology
  • Bacterial Pathogenesis
  • Infectious Diseases

Background:

  • Salmonella infection survival depends on adapting to host environmental challenges, including acidic pH.
  • Acidic conditions are encountered by Salmonella during host cell invasion and intracellular replication.
  • Gene STM1485 is significantly upregulated by Salmonella within host cells, suggesting a role in pathogenesis.

Purpose of the Study:

  • To functionally characterize the role of the acid-induced gene STM1485 in Salmonella pathogenesis.
  • To investigate the impact of STM1485 on Salmonella survival, replication, and virulence within host cells and in vivo.

Main Methods:

  • Construction and in vitro analysis of a ΔSTM1485 mutant for growth and acid tolerance.
  • Assessment of intracellular replication and virulence of the mutant within host cells.
  • Evaluation of Salmonella pathogenicity island-2 (SPI-2) translocon protein translocation (SseB, SseD).
  • Murine typhoid model infection via intra-gastric route to determine competitive indices (CI) in spleen, liver, and lymph nodes.

Main Results:

  • The ΔSTM1485 mutant showed no growth defect at acidic pH (4.5) or altered acid tolerance response in vitro.
  • Intracellular proliferation of the ΔSTM1485 mutant within host cells was significantly compromised, with virulence restored upon complementation.
  • Surface translocation of SPI-2 translocon proteins SseB and SseD was reduced in the mutant, correlating with increased co-localization with lysosomes.
  • The ΔSTM1485 mutant exhibited significantly reduced competitive indices in murine spleen, liver, and mesenteric lymph nodes.

Conclusions:

  • The acidic pH-induced gene STM1485 is essential for intracellular replication of Salmonella.
  • STM1485 plays a critical role in Salmonella pathogenesis by facilitating intracellular survival and proliferation, likely through modulation of SPI-2 function.
  • Targeting STM1485 may represent a novel strategy to combat Salmonella infections.

More Related Videos

Automated Analysis of Intracellular Phenotypes of Salmonella Using ImageJ10:39

Automated Analysis of Intracellular Phenotypes of Salmonella Using ImageJ

Published on: August 9, 2022

A Non-Coding Small RNA MicC Contributes to Virulence in Outer Membrane Proteins in Salmonella Enteritidis06:30

A Non-Coding Small RNA MicC Contributes to Virulence in Outer Membrane Proteins in Salmonella Enteritidis

Published on: January 27, 2021

Related Concept Videos

DNA Bacteriophages01:26

DNA Bacteriophages

Bacteriophages, or phages, are viruses that specifically infect bacteria, utilizing their genetic material to hijack host cellular machinery for replication. DNA bacteriophages employ single-stranded DNA (ssDNA) or double-stranded DNA (dsDNA) genomes. These phages exhibit diverse replication strategies and host interactions, influencing their ecological roles and applications in biotechnology and medicine.ssDNA BacteriophagesssDNA phages, with their small genomes, utilize unique strategies to...
Stringent Response in E. coli01:23

Stringent Response in E. coli

Bacterial growth is closely tied to nutrient availability, with cells proliferating exponentially under favorable conditions and entering a stationary phase when resources become scarce. This transition is mediated by a regulatory mechanism known as the stringent response, which allows bacteria to adapt to nutrient deprivation by modulating gene expression and metabolic activity.During nutrient scarcity, intracellular amino acid levels decline. It results in the accumulation of uncharged tRNAs...
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...
Lysogenic Cycle of Bacteriophages00:43

Lysogenic Cycle of Bacteriophages

In contrast to the lytic cycle, phages infecting bacteria via the lysogenic cycle do not immediately kill their host cell. Instead, they combine their genome with the host genome, allowing the bacteria to replicate the phage DNA along with the bacterial genome. The incorporated copy of the phage genome is called the prophage. Some prophages can re-activate and enter the lytic cycle. This often occurs in response to a perturbation, such as DNA damage, but can also transpire in the absence of...
Gene Regulation During Sporulation01:17

Gene Regulation During Sporulation

Sporulation is a complex developmental process that allows certain Gram-positive bacteria, such as Bacillus subtilis and Clostridium species, to survive extreme environmental conditions. This process is tightly regulated by a series of signaling cascades and transcriptional controls, ensuring the formation of a highly resistant endospore.Sporulation is triggered by unfavorable conditions, such as nutrient depletion, and is governed by a phosphorelay system. One of the sensor kinases, such as...
Viral Replication: Lysogenic Cycle01:16

Viral Replication: Lysogenic Cycle

The lysogenic cycle is a crucial viral replication strategy that allows bacteriophages to persist within host cells without immediately destroying them. This process is primarily observed in temperate phages, such as bacteriophage lambda (λ), which infects Escherichia coli. The cycle allows the viral genome to persist across bacterial generations while keeping host cells viable.Integration of the Viral GenomeUpon infection, bacteriophage lambda attaches to the bacterial surface and injects its...