Epigenetic Phase Variation in Bacterial Pathogens

Woude, Marjan W. van der

doi:10.1007/978-3-319-55021-3_7

Cited by 23 publications

(2 citation statements)

References 44 publications

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“…The observed loss and reestablishment of the auto-aggregation phenotype could be explained by phase variation, which leads to an heterogenous culture via an ON/OFF switch [ 59 ]. DNA inversions cause phase-variable surface protein expression [ 60 – 66 ] partially via genetic modifications by the activity of recombinases [ 60 , 61 , 67 – 70 ].…”

Section: Discussionmentioning

confidence: 99%

Bistable auto-aggregation phenotype in Lactiplantibacillus plantarum emerges after cultivation in in vitro colonic microbiota

et al. 2021

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Background Auto-aggregation is a desired property for probiotic strains because it is suggested to promote colonization of the human intestine, to prevent pathogen infections and to modulate the colonic mucosa. We recently reported the generation of adapted mutants of Lactiplantibacillus plantarum NZ3400, a derivative of the model strain WCFS1, for colonization under adult colonic conditions of PolyFermS continuous intestinal fermentation models. Here we describe and characterize the emerge of an auto-aggregating phenotype in L. plantarum NZ3400 derivatives recovered from the modelled gut microbiota. Results L. plantarum isolates were recovered from reactor effluent of four different adult microbiota and from spontaneously formed reactor biofilms. Auto-aggregation was observed in L. plantarum recovered from all microbiota and at higher percentage when recovered from biofilm than from effluent. Further, auto-aggregation percentage increased over time of cultivation in the microbiota. Starvation of the gut microbiota by interrupting the inflow of nutritive medium enhanced auto-aggregation, suggesting a link to nutrient availability. Auto-aggregation was lost under standard cultivation conditions for lactobacilli in MRS medium. However, it was reestablished during growth on sucrose and maltose and in a medium that simulates the abiotic gut environment. Remarkably, none of these conditions resulted in an auto-aggregation phenotype in the wild type strain NZ3400 nor other non-aggregating L. plantarum, indicating that auto-aggregation depends on the strain history. Whole genome sequencing analysis did not reveal any mutation responsible for the auto-aggregation phenotype. Transcriptome analysis showed highly significant upregulation of LP_RS05225 (msa) at 4.1–4.4 log2-fold-change and LP_RS05230 (marR) at 4.5–5.4 log2-fold-change in all auto-aggregating strains compared to non-aggregating. These co-expressed genes encode a mannose-specific adhesin protein and transcriptional regulator, respectively. Mapping of the RNA-sequence reads to the promoter region of the msa-marR operon reveled a DNA inversion in this region that is predominant in auto-aggregating but not in non-aggregating strains. This strongly suggests a role of this inversion in the auto-aggregation phenotype. Conclusions L. plantarum NZ3400 adapts to the in vitro colonic environment by developing an auto-aggregation phenotype. Similar aggregation phenotypes may promote gut colonization and efficacy of other probiotics and should be further investigated by using validated continuous models of gut fermentation such as PolyFermS.

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Section: Discussionmentioning

confidence: 99%

Bistable auto-aggregation phenotype in Lactiplantibacillus plantarum emerges after cultivation in in vitro colonic microbiota

et al. 2021

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“…This study shows that std expression is bistable, a trait shared with other adhesin-encoding operons [ 32 ]. A difference, however, is that std appears to be more than just a fimbrial operon: two products of the std operon, StdE and StdF, have DNA-binding capacity and activate or repress transcription of multiple genes.…”

Section: Introductionmentioning

confidence: 99%

Formation of phenotypic lineages in Salmonella enterica by a pleiotropic fimbrial switch

et al. 2018

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The std locus of Salmonella enterica, an operon acquired by horizontal transfer, encodes fimbriae that permit adhesion to epithelial cells in the large intestine. Expression of the std operon is bistable, yielding a major subpopulation of StdOFF cells (99.7%) and a minor subpopulation of StdON cells (0.3%). In addition to fimbrial proteins, the std operon encodes two proteins, StdE and StdF, that have DNA binding capacity and control transcription of loci involved in flagellar synthesis, chemotaxis, virulence, conjugal transfer, biofilm formation, and other cellular functions. As a consequence of StdEF pleiotropic transcriptional control, StdON and StdOFF subpopulations may differ not only in the presence or absence of Std fimbriae but also in additional phenotypic traits. Separation of StdOFF and StdON lineages by cell sorting confirms the occurrence of lineage-specific features. Formation of StdOFF and StdON lineages may thus be viewed as a rudimentary bacterial differentiation program.

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Contribution of SPI-1 bistability to Salmonella enterica cooperative virulence: insights from single cell analysis

Sánchez-Romero

Casadesús

2018

Sci Rep

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Salmonella enterica pathogenicity island 1 (SPI-1) is a gene cluster that encodes a type III secretion system and effectors involved in epithelial cell invasion. SPI-1 undergoes bistable expression, with concomitant formation of SPI-1ON and SPI-1OFF lineages. This study describes single cell analysis of SP1-1 bistability and epithelial cell invasion, and reports the unsuspected observation that optimal invasion of epithelial cells requires the presence of both SPI-1ON and SPI-1OFF subpopulations. The contribution of SPI-1OFF cells to optimal invasion may rely on their ability to invade epithelial cells if a SPI-1ON subpopulation is present. In fact, Salmonella SPI-1 mutants are also able to invade epithelial cells in the presence of SPI-1ON Salmonellae, a phenomenon described in the 1990’s by Galán and co-workers. Invasion by SPI-1OFF cells does not seem to involve a diffusible factor. A small number of SPI-1ON cells is sufficient to endow the bacterial population with invasion capacity, a feature that may permit host colonization regardless of the bottlenecks encountered by Salmonella populations inside animals.

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Epigenetic Phase Variation in Bacterial Pathogens

Cited by 23 publications

References 44 publications

Bistable auto-aggregation phenotype in Lactiplantibacillus plantarum emerges after cultivation in in vitro colonic microbiota

Bistable auto-aggregation phenotype in Lactiplantibacillus plantarum emerges after cultivation in in vitro colonic microbiota

Formation of phenotypic lineages in Salmonella enterica by a pleiotropic fimbrial switch

Contribution of SPI-1 bistability to Salmonella enterica cooperative virulence: insights from single cell analysis

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