Role of asparagine 1134 in glucosidic bond and transglycosylation specificity of reuteransucrase from Lactobacillus reuteri 121

In this study, the biofilm-forming potential of intestinal Lactobacillus reuteri strains under different culture conditions was characterized by microtiter plate biofilm assays. Moreover, the spatial organization of exogenously applied L. reuteri L2/6 (a pig isolate) at specific locations in gastrointestinal tract of monoassociated mice was investigated by fluorescence in situ hybridization. We did not detect biofilm formation by tested strains in nutrient-rich de Man–Rogosa–Sharpe (MRS) medium. On the contrary, a highly positive biofilm formation was observed in medium with lower accessibility to the carbon sources and lack of salts. The results obtained confirmed the significant role of Tween 80 and the quantity and nature of the sugars in the growth medium in biofilm formation. The omission of Tween 80 in MRS medium favored the formation of biofilm. Abundant biofilm formation was detected in the presence of lactose, galactose, and glucose. However, a gradual increase in sugar concentration triggered a significant decrease in biofilm formation. In addition, conditions related to the gastrointestinal environment, such as low pH and the presence of bile and mucins, highly modulated biofilm production. This effect seems to be dependent on the specificity and properties of the medium used for cultivation. From the evidence provided by this study we conclude that the biofilm formation capacity of L. reuteri is strongly dependent on the environmental factors and culture medium used.

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Structural basis for the role of serine-rich repeat proteins from Lactobacillus reuteri in gut microbe–host interactions

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1715016115 ◽

2018 ◽

Vol 115 (12) ◽

pp. E2706-E2715 ◽

Cited By ~ 12

Author(s):

Saannya Sequeira ◽

Devon Kavanaugh ◽

Donald A. MacKenzie ◽

Tanja Šuligoj ◽

Samuel Walpole ◽

...

Keyword(s):

Lactobacillus Reuteri ◽

Structural Information ◽

Bacterial Species ◽

Surface Proteins ◽

Structural Basis ◽

Gene Encoding ◽

Rhamnogalacturonan I ◽

Host Microbe Interactions ◽

Dynamics Simulations

Lactobacillus reuteri, a Gram-positive bacterial species inhabiting the gastrointestinal tract of vertebrates, displays remarkable host adaptation. Previous mutational analyses of rodent strain L. reuteri 100-23C identified a gene encoding a predicted surface-exposed serine-rich repeat protein (SRRP100-23) that was vital for L. reuteri biofilm formation in mice. SRRPs have emerged as an important group of surface proteins on many pathogens, but no structural information is available in commensal bacteria. Here we report the 2.00-Å and 1.92-Å crystal structures of the binding regions (BRs) of SRRP100-23 and SRRP53608 from L. reuteri ATCC 53608, revealing a unique β-solenoid fold in this important adhesin family. SRRP53608-BR bound to host epithelial cells and DNA at neutral pH and recognized polygalacturonic acid (PGA), rhamnogalacturonan I, or chondroitin sulfate A at acidic pH. Mutagenesis confirmed the role of the BR putative binding site in the interaction of SRRP53608-BR with PGA. Long molecular dynamics simulations showed that SRRP53608-BR undergoes a pH-dependent conformational change. Together, these findings provide mechanistic insights into the role of SRRPs in host–microbe interactions and open avenues of research into the use of biofilm-forming probiotics against clinically important pathogens.

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Horizontal Transfer of the Salmonella enterica Serovar Infantis Resistance and Virulence Plasmid pESI to the Gut Microbiota of Warm-Blooded Hosts

mBio ◽

10.1128/mbio.01395-16 ◽

2016 ◽

Vol 7 (5) ◽

Cited By ~ 35

Author(s):

Gili Aviv ◽

Galia Rahav ◽

Ohad Gal-Mor

Keyword(s):

Multidrug Resistance ◽

Gut Microbiota ◽

Salmonella Enterica ◽

Pathogenic Bacteria ◽

Lactobacillus Reuteri ◽

Bacterial Species ◽

Microbial Evolution ◽

Virulence Plasmid ◽

Transmission Properties

ABSTRACT Salmonella enterica serovar Infantis is one of the prevalent salmonellae worldwide. Recently, we showed that the emergence of S . Infantis in Israel was facilitated by the acquisition of a unique megaplasmid (pESI) conferring multidrug resistance and increased virulence phenotypes. Here we elucidate the ecology, transmission properties, and regulation of pESI. We show that despite its large size (~280 kb), pESI does not impose a significant metabolic burden in vitro and that it has been recently fixed in the domestic S . Infantis population. pESI conjugation and the transcription of its pilus ( pil ) genes are inhibited at the ambient temperature (27°C) and by ≥1% bile but increased under temperatures of 37 to 41°C, oxidative stress, moderate osmolarity, and the microaerobic conditions characterizing the intestinal environment of warm-blooded animals. The pESI-encoded protein TraB and the oxygen homeostasis regulator Fnr were identified as transcriptional regulators of pESI conjugation. Using the mouse model, we show that following S . Infantis infection, pESI can be horizontally transferred to the gut microbiota, including to commensal Escherichia coli strains. Possible transfer, but not persistence, of pESI was also observed into Gram-positive mouse microbiota species, especially Lactobacillus reuteri . Moreover, pESI was demonstrated to further disseminate from gut microbiota to S. enterica serovar Typhimurium, in the context of gastrointestinal infection. These findings exhibit the ability of a selfish clinically relevant megaplasmid to distribute to and from the microbiota and suggest an overlooked role of the microbiota as a reservoir of mobile genetic elements and intermediator in the spread of resistance and virulence genes between commensals and pathogenic bacteria. IMPORTANCE Plasmid conjugation plays a key role in microbial evolution, enabling the acquisition of new phenotypes, including resistance and virulence. Salmonella enterica serovar Infantis is one of the ubiquitous salmonellae worldwide and a major cause of foodborne infections. Previously, we showed that the emergence of S . Infantis in Israel has involved the acquisition of a unique megaplasmid (pESI) conferring multidrug resistance and increased virulence phenotypes. Recently, the emergence of another S . Infantis strain carrying a pESI-like plasmid was identified in Italy, suggesting that the acquisition of pESI may be common to different emergent S . Infantis populations globally. Transmission of this plasmid to other strains or bacterial species is an alarming scenario. Understanding the ecology, regulation, and transmission properties of clinically relevant plasmids and the role of the microbiota in their spreading offers a new mechanism explaining the emergence of new pathogenic and resistant biotypes and may assist in the development of appropriate surveillance and prevention measures.

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The role of Lactobacillus reuteri DSM 17938 for the absorption of iron preparations in children with iron deficiency anemia

Korean Journal of Pediatrics ◽

10.3345/kjp.2018.07024 ◽

2019 ◽

Vol 62 (5) ◽

pp. 173-178 ◽

Cited By ~ 1

Author(s):

Jeanette Manoppo ◽

Hilda Tasiringan ◽

Audrey Wahani ◽

Adrian Umboh ◽

Max Mantik

Keyword(s):

Iron Deficiency ◽

Iron Deficiency Anemia ◽

Lactobacillus Reuteri ◽

Deficiency Anemia

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Role of Lactobacillus rhamnosus (FloraActive™) 19070-2 and Lactobacillus reuteri (FloraActive™) 12246 in Infant Colic: A Randomized Dietary Study

Nutrients ◽

10.3390/nu10121975 ◽

2018 ◽

Vol 10 (12) ◽

pp. 1975 ◽

Cited By ~ 5

Author(s):

Sergei Gerasimov ◽

Jesper Gantzel ◽

Nataliia Dementieva ◽

Olha Schevchenko ◽

Orisia Tsitsura ◽

...

Keyword(s):

Vitamin D3 ◽

Lactobacillus Reuteri ◽

Lactobacillus Rhamnosus ◽

Control Group ◽

Infant Cry ◽

Breastfed Infants ◽

Infant Colic ◽

Dietary Study ◽

And Control

Infant colic is a common condition of unknown pathogenesis that brings frustration to families seeking for effective management. Accumulating evidence suggests that some single strains of lactobacilli may play a positive dietary role in attenuation of colic in exclusively breastfed infants. The objective of this study was to evaluate a mixture of two Lactobacillus strains in decreasing infant cry and fuss in this population. Infants aged 4–12 weeks received L. rhamnosus 19070-2 and L. reuteri 12246 in a daily dose of 250 × 106 CFU, 3.33 mg of fructooligosaccharide, and 200 IU of vitamin D3 (84 infants, probiotic group) or just vitamin D3 (84 infants, control group) for 28 days. Cry and fuss time were measured with validated Baby’s Day Diary on days 0 and 28. At baseline, mean (SD) duration of cry and fuss time was comparable in the probiotic and control groups: 305 (81) vs. 315 (90) min., respectively (p = 0.450). On day 28, mean cry and fuss time became statistically different: 142 (89) vs. 199 (72), respectively (p < 0.05). Mean change in cry and fuss time from day 0 through day 28 was −163 (99) minutes in the probiotic and −116 (94) minutes in the control group (p = 0.019). Our findings confirm that lactobacilli decrease cry and fuss time and provide a dietary support in exclusively breastfed infants with colic.

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Strain-specific diversity of mucus-binding proteins in the adhesion and aggregation properties of Lactobacillus reuteri

Microbiology ◽

10.1099/mic.0.043265-0 ◽

2010 ◽

Vol 156 (11) ◽

pp. 3368-3378 ◽

Cited By ~ 108

Author(s):

Donald A. MacKenzie ◽

Faye Jeffers ◽

Mary L. Parker ◽

Amandine Vibert-Vallet ◽

Roy J. Bongaerts ◽

...

Keyword(s):

Cell Wall ◽

Cell Surface ◽

Binding Proteins ◽

Lactobacillus Reuteri ◽

Surface Protein ◽

Cell Aggregation ◽

Spontaneous Mutant ◽

Vertebrate Hosts

Mucus-binding proteins (MUBs) have been revealed as one of the effector molecules involved in mechanisms of the adherence of lactobacilli to the host; mub, or mub-like, genes are found in all of the six genomes of Lactobacillus reuteri that are available. We recently reported the crystal structure of a Mub repeat from L. reuteri ATCC 53608 (also designated strain 1063), revealing an unexpected recognition of immunoglobulins. In the current study, we explored the diversity of the ATCC 53608 mub gene, and MUB expression levels in a large collection of L. reuteri strains isolated from a range of vertebrate hosts. This analysis revealed that the MUB was only detectable on the cell surface of two highly related isolates when using antibodies that were raised against the protein. There was considerable variation in quantitative mucus adhesion in vitro among L. reuteri strains, and mucus binding showed excellent correlation with the presence of cell-surface ATCC 53608 MUB. ATCC 53608 MUB presence was further highly associated with the autoaggregation of L. reuteri strains in washed cell suspensions, suggesting a novel role of this surface protein in cell aggregation. We also characterized MUB expression in representative L. reuteri strains. This analysis revealed that one derivative of strain 1063 was a spontaneous mutant that expressed a C-terminally truncated version of MUB. This frameshift mutation was caused by the insertion of a duplicated 13 nt sequence at position 4867 nt in the mub gene, producing a truncated MUB also lacking the C-terminal LPxTG region, and thus unable to anchor to the cell wall. This mutant, designated 1063N (mub-4867i), displayed low mucus-binding and aggregation capacities, further providing evidence for the contribution of cell-wall-anchored MUB to such phenotypes. In conclusion, this study provided novel information on the functional attributes of MUB in L. reuteri, and further demonstrated that MUB and MUB-like proteins, although present in many L. reuteri isolates, show a high genetic heterogeneity among strains.

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Role of Lactobacillus reuteri in Human Health and Diseases

Frontiers in Microbiology ◽

10.3389/fmicb.2018.00757 ◽

2018 ◽

Vol 9 ◽

Cited By ~ 87

Author(s):

Qinghui Mu ◽

Vincent J. Tavella ◽

Xin M. Luo

Keyword(s):

Human Health ◽

Lactobacillus Reuteri

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Role of Lactobacillus reuteri cell and mucus-binding protein A (CmbA) in adhesion to intestinal epithelial cells and mucus in vitro

Microbiology ◽

10.1099/mic.0.073551-0 ◽

2014 ◽

Vol 160 (4) ◽

pp. 671-681 ◽

Cited By ~ 41

Author(s):

Hanne Jensen ◽

Stefan Roos ◽

Hans Jonsson ◽

Ida Rud ◽

Stine Grimmer ◽

...

Keyword(s):

Gastrointestinal Tract ◽

Epithelial Cells ◽

Lactobacillus Reuteri ◽

Intestinal Epithelial Cells ◽

Protein A ◽

Surface Protein ◽

Null Mutation ◽

Intestinal Epithelial

Lactobacillus reuteri, a symbiotic inhabitant of the gastrointestinal tract in humans and animals, is marketed as a probiotic. The ability to adhere to intestinal epithelial cells and mucus is an interesting property with regard to probiotic features such as colonization of the gastrointestinal tract and interaction with the host. Here, we present a study performed to elucidate the role of sortase (SrtA), four putative sortase-dependent proteins (SDPs), and one C-terminal membrane-anchored cell surface protein of Lactobacillus reuteri ATCC PTA 6475 in adhesion to Caco-2 cells and mucus in vitro. This included mutagenesis of the genes encoding these proteins and complementation of mutants. A null mutation in hmpref0536_10255 encoding srtA resulted in significantly reduced adhesion to Caco-2 cells and mucus, indicating involvement of SDPs in adhesion. Evaluation of the bacterial adhesion revealed that of the five putative surface protein mutants tested, only a null mutation in the hmpref0536_10633 gene, encoding a putative SDP with an LPxTG motif, resulted in a significant loss of adhesion to both Caco-2 cells and mucus. Complementation with the functional gene on a plasmid restored adhesion to Caco-2 cells. However, complete restoration of adhesion to mucus was not achieved. Overexpression of hmpref0536_10633 in strain ATCC PTA 6475 resulted in an increased adhesion to Caco-2 cells and mucus compared with the WT strain. We conclude from these results that, among the putative surface proteins tested, the protein encoded by hmpref0536_10633 plays a critical role in binding of Lactobacillus reuteri ATCC PTA 6475 to Caco-2 cells and mucus. Based on this, we propose that this LPxTG motif containing protein should be referred to as cell and mucus binding protein A (CmbA).

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