English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Toxin-antitoxin (TA) modules consist of a pair of genes that encode two components: a protein toxin and an antitoxin, which may be in the form of either a labile protein or an antisense small RNA. Here we describe, to the best of our knowledge, the first functional chromosomal type I TA system in streptococci. Our model organism is the oral pathogen  Streptococcus mutans . Our results showed that the genome of  S. mutans  UA159 reference strain harbors a previously unannotated Fst-like toxin (Fst-Sm) and its  cis -encoded small RNA antitoxin (srSm) converging towards the end of the toxin gene in IGR176, a small intergenic region of 318 nt. Fst-Sm is a small hydrophobic peptide of 32 amino acid residues with homology to the Fst toxin family. Transcripts of ∼200 nt and ∼70 nt specific to  fst-Sm  mRNA and  srSm  RNA, respectively, were detected by Northern blot analysis throughout  S. mutans  growth. The toxin mRNA was considerably more stable than its cognate antitoxin. The half-life of  srSm  RNA was determined to be ∼30 min, while  fst-Sm  mRNA had a half-life of ∼90 min. Both  fst-Sm  and  srSm  RNAs were transcribed across direct tandem repeats providing a region of complementarity for inhibition of toxin translation. Overproduction of Fst-Sm had a toxic effect on  E. coli  and  S. mutans  cells which can be neutralized by coexpression of  srSm  RNA. Deletion of  fst-Sm / srSm  locus or overexpression of Fst-Sm/srSm had no effect on  S. mutans  cell growth in liquid medium and no differences in the total biofilm biomass were noted. In contrast, mild-overproduction of Fst-Sm/srSm type I TA system decreases the levels of persister cells tolerant to bacterial cell wall synthesis inhibitors.

Characterization of a Streptococcus mutans Intergenic Region Containing a Small Toxic Peptide and Its cis-Encoded Antisense Small RNA Antitoxin