AI Article Synopsis

  • The study explores the role of the luxS/AI-2 signaling pathway in Streptococcus pyogenes, focusing on its impact on metabolism and pathogenicity under stress conditions.
  • It was found that while luxS plays a minor role in the activated methyl cycle, its loss increased the bacteria's acid tolerance and survival in challenging environments.
  • The results suggest that low luxS expression may enhance the bacterium's ability to survive and express virulence factors during infections.

Article Abstract

Background: The luxS/AI-2 signaling pathway has been reported to interfere with important physiological and pathogenic functions in a variety of bacteria. In the present study, we investigated the functional role of the streptococcal luxS/AI-2 system in metabolism and diverse aspects of pathogenicity including the adaptation of the organism to stress conditions using two serotypes of Streptococcus pyogenes, M1 and M19.

Results: Exposing wild-type and isogenic luxS-deficient strains to sulfur-limited media suggested a limited role for luxS in streptococcal activated methyl cycle metabolism. Interestingly, loss of luxS led to an increased acid tolerance in both serotypes. Accordingly, luxS expression and AI-2 production were reduced at lower pH, thus linking the luxS/AI-2 system to stress adaptation in S. pyogenes. luxS expression and AI-2 production also decreased when cells were grown in RPMI medium supplemented with 10% serum, considered to be a host environment-mimicking medium. Furthermore, interaction analysis with epithelial cells and macrophages showed a clear advantage of the luxS-deficient mutants to be internalized and survive intracellularly in the host cells compared to the wild-type parents. In addition, our data revealed that luxS influences the expression of two virulence-associated factors, the fasX regulatory RNA and the virulence gene sibA (psp).

Conclusion: Here, we suggest that the group A streptococcal luxS/AI-2 system is not only involved in the regulation of virulence factor expression but in addition low level of luxS expression seems to provide an advantage for bacterial survival in conditions that can be encountered during infections.

Download full-text PDF

Source
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2603038PMC
http://dx.doi.org/10.1186/1471-2180-8-188DOI Listing

Publication Analysis

Top Keywords

luxs/ai-2 system
16
streptococcal luxs/ai-2
12
luxs expression
12
group streptococcal
8
system metabolism
8
host cells
8
expression ai-2
8
ai-2 production
8
luxs
6
luxs/ai-2
5

Similar Publications

Mechanisms of S. agalactiae promoting G. vaginalis biofilm formation leading to recurrence of BV.

NPJ Biofilms Microbiomes

November 2024

Department of Obstetrics and Gynecology, Beijing Tsinghua Changgung Hospital, School of Clinical Medicine, Tsinghua University, Beijing, 102218, China.

Previous research has established that the formation of Gardnerella vaginalis (GV) biofilm is one of the primary reasons for bacterial vaginosis (BV) recurrence. This study was the first to explore the impact of Streptococcus agalactiae (group B Streptococcus, GBS) on GV biofilm in a co-culture scenario. The results revealed that GBS could significantly increased the GV biomass in 48-hours dual-species biofilms.

View Article and Find Full Text PDF

LuxS/AI-2 system facilitates the dissemination of antibiotic-resistant plasmids in Klebsiella pneumoniae.

Int J Antimicrob Agents

December 2024

Department of Clinical Laboratory Medicine, Shanghai Pulmonary Hospital, Tongji University School of Medicine, Shanghai 200082, People's Republic of China; Department of Laboratory Medicine, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, People's Republic of China. Electronic address:

Plasmid conjugation is a central mechanism driving the dissemination of antibiotic resistance in Klebsiella pneumoniae. However, the conjugative operon requires specific stimuli for activation. Identifying signals and elucidating the underlying mechanisms is crucial in combating plasmid spread.

View Article and Find Full Text PDF

The absence of reduces the invasion of but is not essential for virulence.

Front Vet Sci

August 2024

Beijing Key Laboratory for Prevention and Control of Infectious Diseases in Livestock and Poultry, Institute of Animal Husbandry and Veterinary Medicine, Beijing Academy of Agriculture and Forestry Sciences, Beijing, China.

Article Synopsis
  • The research investigates the role of the LuxS/AI-2 quorum-sensing system in a respiratory pathogen affecting poultry, specifically focusing on a certain gene's function.
  • Findings reveal that the deletion of this gene impairs the pathogen's ability to invade host cells, but does not significantly alter its overall pathogenicity in chickens.
  • Despite the reduced invasion capability, both the mutant and wild-type strains caused infections in chickens, with only minor differences in symptoms observed.
View Article and Find Full Text PDF

Quorum sensing (QS) can regulate the production of multiple functional factors in bacteria, but the process of identifying its regulatory targets is very complex and labor-intensive. In this study, an efficient and rapid method to find QS targets through prediction was used. The genome of Lactiplantibacillus plantarum (L.

View Article and Find Full Text PDF

The quality and flavor profile of fermented milk produced by ABT-T is influenced by the gene in the quorum sensing system.

Food Chem X

October 2024

State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-products, Ningbo University, Ningbo, Zhejiang 315211, China.

The /AI-2 quorum sensing (QS) system of regulates strain acid tolerance, yet its impact on milk fermentation remains unclear. This study aimed to elucidate the mechanism of and gene overexpression in the /AI-2 system of ABT-T on fermented milk quality using metabolomics. Results showed that gene overexpression had a greater impact on milk quality than the wild-type strain or gene overexpression strain.

View Article and Find Full Text PDF

Want AI Summaries of new PubMed Abstracts delivered to your In-box?

Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!

A PHP Error was encountered

Severity: Notice

Message: fwrite(): Write of 34 bytes failed with errno=28 No space left on device

Filename: drivers/Session_files_driver.php

Line Number: 272

Backtrace:

A PHP Error was encountered

Severity: Warning

Message: session_write_close(): Failed to write session data using user defined save handler. (session.save_path: /var/lib/php/sessions)

Filename: Unknown

Line Number: 0

Backtrace: