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Vega LA, Sansón-Iglesias M, Mukherjee P, Buchan K, Morrison G, Hohlt AE, Flores AR. LiaR-dependent gene expression contributes to antimicrobial responses in group A Streptococcus. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.04.04.588141. [PMID: 38617309 PMCID: PMC11014544 DOI: 10.1101/2024.04.04.588141] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/16/2024]
Abstract
The ability to sense and respond to host defenses is essential for pathogen survival. Some mechanisms involve two-component systems (TCS) that respond to host molecules, such as antimicrobial peptides (AMPs) and activate specific gene regulatory pathways to aid in survival. Alongside TCSs, bacteria coordinate cell division proteins, chaperones, cell wall sortases and secretory translocons at discrete locations within the cytoplasmic membrane, referred to as functional membrane microdomains (FMMs). In Group A Streptococcus (GAS), the FMM or "ExPortal" coordinates protein secretion, cell wall synthesis and sensing of AMP-mediated cell envelope stress via the LiaFSR three-component system. Previously we showed GAS exposure to a subset of AMPs (α-defensins) activates the LiaFSR system by disrupting LiaF and LiaS co-localization in the ExPortal, leading to increased LiaR phosphorylation, expression of the transcriptional regulator SpxA2, and altered GAS virulence gene expression. The mechanisms by which LiaFSR integrates cell envelope stress with responses to AMP activity and virulence are not fully elucidated. Here, we show the LiaFSR regulon is comprised of genes encoding SpxA2 and three membrane-associated proteins: a PspC domain-containing protein (PCP), the lipoteichoic acid-modifying protein LafB and the membrane protein insertase YidC2. Our data show phosphorylated LiaR induces transcription of these genes via a conserved operator, whose disruption attenuates GAS virulence and increases susceptibility to AMPs in a manner primarily dependent on differential expression of SpxA2. Our work expands understanding of the LiaFSR regulatory network in GAS and identifies targets for further investigation of mechanisms of cell envelope stress tolerance contributing to GAS pathogenesis.
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Kim YY, Kim JC, Kim S, Yang JE, Kim HM, Park HW. Heterotypic stress-induced adaptive evolution enhances freeze-drying tolerance and storage stability of Leuconostoc mesenteroides WiKim33. Food Res Int 2024; 175:113731. [PMID: 38128991 DOI: 10.1016/j.foodres.2023.113731] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2023] [Revised: 11/15/2023] [Accepted: 11/22/2023] [Indexed: 12/23/2023]
Abstract
Lactic acid bacteria (LAB) are currently being investigated for their potential use as probiotics and starter cultures. Researchers have developed powdering processes for the commercialization of LAB. Previous studies have focused on identifying innovative cryoprotective agents and freeze-drying (FD) techniques to enhance the stability of LAB. In this study, adaptive laboratory evolution (ALE) was employed to develop a strain with high FD tolerance and enhanced storage stability. Leuconostoc mesenteroids WiKim33 was subjected to heterotypic shock (heat and osmosis shock) to induce the desired phenotype and genotype. An FD-tolerant enhanced Leu. mesenteroides WiKim33 strain (ALE50) was obtained, which harbored a modified fatty acid composition and cell envelope characteristics. Specifically, ALE50 showed a lower unsaturated fatty acid (UFA)/saturated fatty acid (SFA) ratio and a higher cyclic fatty acid (CFA) composition. Moreover, the exopolysaccharide (EPS) thickness increased significantly by 331% compared to that of the wild type (WT). FD tolerance, which was evaluated using viability testing after FD, was enhanced by 33.4%. Overall, we demonstrated the feasibility of ALE to achieve desirable characteristics and provided insights into the mechanisms underlying increased FD tolerance.
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Affiliation(s)
- Yeong Yeol Kim
- Technology Innovation Research Division, World Institute of Kimchi, Gwangju 61755, Republic of Korea; Department of Integrative Food, Bioscience and Biotechnology, Chonnam National University, Gwangju 61186, Republic of Korea
| | - Jong-Cheol Kim
- Technology Innovation Research Division, World Institute of Kimchi, Gwangju 61755, Republic of Korea
| | - Seulbi Kim
- Technology Innovation Research Division, World Institute of Kimchi, Gwangju 61755, Republic of Korea; Division of Applied Bioscience & Biotechnology, Chonnam National University, Gwangju 61186, Republic of Korea
| | - Jung Eun Yang
- Technology Innovation Research Division, World Institute of Kimchi, Gwangju 61755, Republic of Korea
| | - Ho Myeong Kim
- Technology Innovation Research Division, World Institute of Kimchi, Gwangju 61755, Republic of Korea.
| | - Hae Woong Park
- Technology Innovation Research Division, World Institute of Kimchi, Gwangju 61755, Republic of Korea.
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Hsu CC, Hsu RB, Oon XH, Chen YT, Chen JW, Hsu CH, Kuo YM, Shih YH, Chia JS, Jung CJ. Streptococcus mutans PrsA mediates AtlA secretion contributing to extracellular DNA release and biofilm formation in the pathogenesis of infective endocarditis. Virulence 2022; 13:1379-1392. [PMID: 35876630 PMCID: PMC9377233 DOI: 10.1080/21505594.2022.2105351] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
The role of secretion chaperone-regulated virulence proteins in the pathogenesis of infective endocarditis (IE) induced by viridans streptococci such as Streptococcus mutans is unclear. In this study, we investigated the contribution of the foldase protein PrsA, a putative parvulin-type peptidyl-prolyl isomerase, to the pathogenesis of S. mutans-induced IE. We found that a prsA-deficient strain had reduced virulence in terms of formation of vegetation on damaged heart valves, as well as reduced autolysis activity, eDNA release and biofilm formation capacity. The secretion and surface exposure of AtlA in vitro was reduced in the prsA-deficient mutant strain, and complementation of recombinant AtlA in the culture medium restored a wild type biofilm phenotype of the prsA-deficient mutant strain. This result suggests that secretion and surface localization of AtlA is regulated by PrsA during biofilm formation. Together, these results demonstrate that S. mutans PrsA could regulate AtlA-mediated eDNA release to contribute to biofilm formation in the pathogenesis of IE.
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Affiliation(s)
- Chih-Chieh Hsu
- Graduate Institute of Clinical Dentistry, School of Dentistry, National Taiwan University, Taipei, Taiwan.,Graduate Institute of Oral Biology, School of Dentistry, National Taiwan University, Taipei, Taiwan
| | - Ron-Bin Hsu
- Department of Surgery, Division of Cardiovascular Surgery, National Taiwan University Hospital , College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Xoong-Harng Oon
- Graduate Institute of Medical Sciences, College of Medicine, Taipei medical University, Taipei, Taiwan.,Department of Microbiology and Immunology, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan
| | - Ya-Tang Chen
- Graduate Institute of Medical Sciences, College of Medicine, Taipei medical University, Taipei, Taiwan
| | - Jeng-Wei Chen
- Department of Surgery, Division of Cardiovascular Surgery, National Taiwan University Hospital , College of Medicine, National Taiwan University, Taipei, Taiwan.,Graduate Institute of Clinical Medicine, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Che-Hao Hsu
- Graduate Institute of Medical Sciences, College of Medicine, Taipei medical University, Taipei, Taiwan
| | - Yu-Min Kuo
- Graduate Institute of Clinical Medicine, College of Medicine, National Taiwan University, Taipei, Taiwan.,Division of Allergy, Immunology, and Rheumatology, Department of Internal Medicine, National Taiwan University Hospital, Taipei, Taiwan
| | - Yi-Hsien Shih
- Department of Dermatology, Taipei Medical University-Shuang Ho Hospital, New Taipei City, Taiwan.,Department of Dermatology, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan
| | - Jean-San Chia
- Graduate Institute of Medical Sciences, College of Medicine, Taipei medical University, Taipei, Taiwan.,Department of Microbiology and Immunology, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan
| | - Chiau-Jing Jung
- Graduate Institute of Medical Sciences, College of Medicine, Taipei medical University, Taipei, Taiwan.,Department of Microbiology and Immunology, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan
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Variability of Genetic Characters Associated with Probiotic Functions in Lacticaseibacillus Species. Microorganisms 2022; 10:microorganisms10051023. [PMID: 35630465 PMCID: PMC9145642 DOI: 10.3390/microorganisms10051023] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Revised: 05/10/2022] [Accepted: 05/11/2022] [Indexed: 11/17/2022] Open
Abstract
This study aims to explore the intra-species distribution of genetic characteristics that favor the persistence in the gastrointestinal tract (GIT) and host interaction of bacteria belonging to species of the Lacticaseibacillus genus. These bacterial species comprise commercial probiotics with the widest use among consumers and strains naturally occurring in GIT and in fermented food. Since little is known about the distribution of genetic traits for adhesion capacity, polysaccharide production, biofilm formation, and utilization of substrates critically important for survival in GIT, which influence probiotic characteristics, a list of genetic determinants possibly involved in such functions was created by a search for specific genes involved in the above aspects in the genome of the extensively characterized probiotic L. rhamnosus GG. Eighty-two gene loci were retrieved and their presence and variability in other Lacticaseibacillus spp. genomes were assessed by alignment with the publicly available fully annotated genome sequences of L. casei, L. paracasei, L. rhamnosus, and L. zeae. Forty-nine of these genes were found to be absent in some strains or species. The remaining genes were conserved and covered almost all the functions considered, indicating that all strains of the genus may exert some probiotic effects. Among the variable loci, a taurine utilization operon and a α-L-fucosidase were examined for the presence/absence in 26 strains isolated from infant feces by PCR-based tests. Results were variable among the isolates, though their common origin indicated the capacity to survive in the intestinal niche. This study indicated that the capacity to exert probiotic actions of Lacticaseibacillus spp. depends on a conserved set of genes but variable genetic factors, whose role is only in part elucidated, are more numerous and can explain the enhanced probiotic characteristics for some strains. The selection of the most promising probiotic candidates to be used in food is feasible by analyzing the presence/absence of a set of variable traits.
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