Related Experiment Video

Updated: Feb 17, 2026

Creation of a Dense Transposon Insertion Library Using Bacterial Conjugation in Enterobacterial Strains Such As Escherichia Coli or Shigella flexneri
11:36

Creation of a Dense Transposon Insertion Library Using Bacterial Conjugation in Enterobacterial Strains Such As Escherichia Coli or Shigella flexneri

Published on: September 23, 2017

16.8K

Dextransucrase Expression Is Concomitant with that of Replication and Maintenance Functions of the pMN1 Plasmid in

Montserrat Nácher-Vázquez1, José A Ruiz-Masó1, María L Mohedano1

  • 1Department of Molecular Microbiology and Infection Biology, Biological Research Center, Spanish National Research Council (CSIC), Madrid, Spain.

Frontiers in Microbiology
|December 7, 2017
PubMed

Insights

The genetic basis for dextran production by Lactobacillus sakei MN1 was identified. A plasmid carries the dextransucrase gene (dsrLS), crucial for synthesizing this antiviral exopolysaccharide.

Area of Science:

  • Microbiology
  • Molecular Biology
  • Biochemistry

Background:

  • Lactobacillus sakei MN1 produces an exopolysaccharide dextran with potential applications in aquaculture due to its antiviral and immunomodulatory properties.
  • Understanding the genetic mechanisms behind dextran synthesis is essential for harnessing its benefits.

Purpose of the Study:

  • To investigate the genetic basis of dextran production by Lactobacillus sakei MN1.
  • To characterize the plasmid carrying the dextransucrase gene and its expression patterns.

Main Methods:

  • Southern blot hybridization to determine gene location.
  • DNA sequencing of the plasmid (pMN1).
  • Gene expression analysis under different growth conditions (sucrose vs. glucose).

Main Results:

  • The dextransucrase gene (dsrLS) is located on a plasmid (pMN1) that replicates via the theta mechanism.
  • pMN1 is a stable, low-copy-number plasmid.
  • dsrLS is constitutively expressed from both monocistronic and polycistronic transcripts, independent of the carbon source.

Conclusions:

  • This study reports the first instance of a plasmid-borne dextransucrase-encoding gene.
  • Co-transcription of plasmid maintenance/replication genes with an enzyme-encoding gene has been established.
  • The findings provide insights into the genetic regulation of dextran synthesis in L. sakei MN1.
Keywords:
Lactobacillus sakeidextrandextransucraselactic acid bacteriaplasmidprobiotics

More Related Videos

Author Spotlight: Advancing Antibiotic Resistance Research Using an Efflux-Deficient Bacterial Strain and a Single-Copy Gene Expression System05:06

Author Spotlight: Advancing Antibiotic Resistance Research Using an Efflux-Deficient Bacterial Strain and a Single-Copy Gene Expression System

Published on: January 5, 2024

1.1K
Measurement of Specific Mycobacterial Mistranslation Rates with Gain-of-function Reporter Systems06:18

Measurement of Specific Mycobacterial Mistranslation Rates with Gain-of-function Reporter Systems

Published on: April 26, 2019

6.5K

Related Concept Videos

Coordination of Gene Expression Processes in Bacteria01:29

Coordination of Gene Expression Processes in Bacteria

The DNA replication, transcription, and translation processes are intricately coupled in bacteria, allowing efficient gene expression and rapid protein synthesis. While this physical and functional coordination is advantageous, it introduces challenges that bacteria overcome through specific regulatory mechanisms.Coupling of Replication, Transcription, and TranslationThe coupling of replication, transcription, and translation is a hallmark of bacterial gene expression. As the replisome unwinds...
706
Translesion DNA Polymerases02:10

Translesion DNA Polymerases

Translesion (TLS) polymerases rescue stalled DNA polymerases at sites of damaged bases by replacing the replicative polymerase and installing a nucleotide across the damaged site. Doing so, TLS allows additional time for the cell to repair the damage before resuming regular DNA replication.
TLS polymerases are found in all three domains of life - archaea, bacteria, and eukaryotes. Of the different classes of TLS polymerases, members of the Y family are fitted with specialized structures that...
11.3K
Conservative Site-specific Recombination and Phase Variation02:53

Conservative Site-specific Recombination and Phase Variation

Because the DNA segments are cut and reorganized in a direction-specific manner, site-specific recombination has emerged as an efficient genetic engineering technique. Flippase and Cyclization recombinases or Flp and Cre, respectively, are two members of the tyrosine recombinase family derived from bacteriophages, that are used to mediate site-specific DNA insertions, deletions, and targeted expression of proteins in mammalian cell lines.
The recognition sites for Cre recombinase called LoxP...
6.9K
Prokaryotic Transcriptional Activators and Repressors01:58

Prokaryotic Transcriptional Activators and Repressors

The organization of prokaryotic genes in their genome is notably different from that of eukaryotes. Prokaryotic genes are organized, such that the genes for proteins involved in the same biochemical process or function are located together in groups. This group of genes, along with their regulatory elements, are collectively known as an operon. The functional genes in an operon are transcribed together to give a single strand of mRNA known as polycistronic mRNA.
Transcription of prokaryotic...
25.7K
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...
1.1K
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...
404