scholarly journals Vibrio cholerae motility in aquatic and mucus-mimicking environments

2021 ◽  
Author(s):  
Marianne Grognot ◽  
Anisha Mittal ◽  
Mattia Mah’moud ◽  
Katja M. Taute
Keyword(s):  
Small Intestine ◽  
Vibrio Cholerae ◽  
Effective Diffusivity ◽  
Statistical Characterization ◽  
Host Environment ◽  
Severe Diarrhea ◽  
Intestinal Mucus ◽  
Mucus Barrier ◽  
Underlying Mechanisms ◽  
Viscous Solutions

Cholera disease is caused by Vibrio cholerae infecting the lining of the small intestine and results in severe diarrhea. V. cholerae ’s swimming motility is known to play a crucial role in pathogenicity and may aid the bacteria in crossing the intestinal mucus barrier to reach sites of infection, but the exact mechanisms are unknown. The cell can be either pushed or pulled by its single polar flagellum, but there is no consensus on the resulting repertoire of motility behaviors. We use high-throughput 3D bacterial tracking to observe V. cholerae swimming in buffer, in viscous solutions of the synthetic polymer PVP, and in mucin solutions that may mimic the host environment. We perform a statistical characterization of its motility behavior on the basis of large 3D trajectory datasets. We find that V. cholerae performs asymmetric run-reverse-flick motility, consisting of a sequence of a forward run, reversal, and a shorter backward run, followed by a turn by approximately 90°, called a flick, preceding the next forward run. Unlike many run-reverse-flick swimmers, V. cholerae ’s backward runs are much shorter than its forward runs, resulting in an increased effective diffusivity. We also find that the swimming speed is not constant, but subject to frequent decreases. The turning frequency in mucin matches that observed in buffer. Run-reverse-flick motility and speed fluctuations are present in all environments studied, suggesting that these behaviors may also occur in natural aquatic habitats as well as the host environment. IMPORTANCE Cholera disease produces vomiting and severe diarrhea and causes approximately 100,000 deaths per year worldwide. The disease is caused by the bacterium Vibrio cholerae colonizing the lining of the small intestine. V. cholerae ’s ability to swim is known to increase its infectivity, but the underlying mechanisms are not known. One possibility is that swimming may aid in crossing the protective mucus barrier that covers the lining of the small intestine. Our work characterizing how V. cholerae swims in environments that mimic properties of the host environment may advance the understanding of how motility contributes to infection.

scholarly journals Vibrio cholerae motility in aquatic and mucus-mimicking environments

2021 ◽  
Author(s):  
Marianne Grognot ◽  
Anisha Mittal ◽  
Mattia Amyra Mah'moud ◽  
Katja M Taute
Keyword(s):  
Vibrio Cholerae ◽  
Effective Diffusivity ◽  
Statistical Characterization ◽  
Host Environment ◽  
Severe Diarrhea ◽  
Intestinal Mucus ◽  
Mucus Barrier ◽  
Viscous Solutions ◽  
Speed Fluctuations

Cholera disease is caused by Vibrio cholerae infecting the lining of the small intestine and results in severe diarrhea. V. cholerae's swimming motility is known to play a crucial role in pathogenicity and may aid the bacteria in crossing the intestinal mucus barrier to reach sites of infection, but the exact mechanisms are unknown. The cell can be either pushed or pulled by its single polar flagellum, but there is no consensus on the resulting repertoire of motility behaviors. We use high-throughput 3D bacterial tracking to observe V. cholerae swimming in buffer, in viscous solutions of the synthetic polymer PVP, and in mucin solutions that may mimic the host environment. We perform a statistical characterization of its motility behavior on the basis of large 3D trajectory datasets. We find that V. cholerae performs asymmetric run-reverse-flick motility, consisting of a sequence of a forward run, reversal, and a shorter backward run, followed by a turn by approximately 90°, called a flick, preceding the next forward run. Unlike many run-reverse-flick swimmers, V. cholerae's backward runs are much shorter than its forward runs, resulting in an increased effective diffusivity. We also find that the swimming speed is not constant, but subject to frequent decreases. The turning frequency in mucin matches that observed in buffer. Run-reverse-flick motility and speed fluctuations are present in all environments studied, suggesting that these behaviors may also occur in natural aquatic habitats as well as the host environment.

scholarly journals Acidic pH reduces Vibrio cholerae motility in mucus by weakening flagellar motor torque

2019 ◽  
Author(s):  
Nguyen T. Q. Nhu ◽  
Helen J. Wang ◽  
Yann S. Dufour
Keyword(s):  
Small Intestine ◽  
Vibrio Cholerae ◽  
Cell Tracking ◽  
Acidic Ph ◽  
Flagellar Motor ◽  
Flagellar Motility ◽  
Motor Torque ◽  
Intestinal Mucus ◽  
Mucus Penetration ◽  
El Tor

AbstractIntestinal mucus is the first line of defense against intestinal pathogens. It acts as a physical barrier between the epithelial tissues and luminal microbes. Enteropathogens, such as Vibrio cholerae, must compromise or circumvent the mucus barrier to establish a successful infection. We investigated how motile V. cholerae is able to penetrate mucus using single cell tracking in unprocessed porcine intestinal mucus. We found that changes in pH within the range of what has been measured in the human small intestine indirectly affect V. cholerae flagellar motor torque, and consequently, mucus penetration. Microrheological measurements indicate that the viscoelasticity of mucus does not change substantially within the physiological pH range and that commercially available mucins do not form gels when rehydrated. Finally, we found that besides the reduction in motor torque, El Tor and Classical biotypes have different responses to acidic pH. For El Tor, acidic pH promotes surface attachment that is mediated by activation of the mannose-sensitive haemagglutinin (MshA) pilus without a measurable change in the total cellular concentration of the secondary messenger cyclic dimeric guanosine monophosphate (c-di-GMP). Overall, our results support that the high torque of V. cholerae flagellar motor is critical for mucus penetration and that the pH gradient in the small intestine is likely an important factor in determining the preferred site of infection.Author summaryThe diarrheal disease cholera is still a burden for populations in developing countries with poor sanitation. To develop effective vaccines and prevention strategies against Vibrio cholerae, we must understand the initial steps of infection leading to the colonization of the small intestine. To infect the host and deliver the cholera toxin, V. cholerae has to penetrate the mucus layer protecting the intestinal tissues. However, V. cholerae’s interactions with intestinal mucus has not been extensively investigated. In this report, we demonstrate using single cell tracking that V. cholerae is able to penetrate native intestinal mucus using flagellar motility. In addition, we found that a strong motor torque is required for mucus penetration and, that torque is weakened in acidic environments even though the motor is powered by a sodium potential. This finding has important implications for understanding the dynamics of infection because pH varies significantly along the small intestine, between individuals, and between species. Blocking mucus penetration by interfering with V. cholerae’s flagellar motility, reinforcing the mucosa, controlling intestinal pH, or manipulating the intestinal microbiome, will offer new strategies to fight cholera.

scholarly journals Alkaline pH increases swimming speed and facilitates mucus penetration for Vibrio cholerae

2021 ◽  
Author(s):  
Nguyen T. Q. Nhu ◽  
John S. Lee ◽  
Helen J. Wang ◽  
Yann S. Dufour
Keyword(s):  
Small Intestine ◽  
Vibrio Cholerae ◽  
Swimming Speed ◽  
Cell Tracking ◽  
Alkaline Ph ◽  
Flagellar Motility ◽  
Human Small Intestine ◽  
Intestinal Mucus ◽  
Mucus Penetration ◽  
El Tor

Intestinal mucus is the first line of defense against intestinal pathogens. It acts as a physical barrier between epithelial tissues and the lumen that enteropathogens must overcome to establish a successful infection. We investigated the motile behavior of two V. cholerae strains (El Tor C6706 and Classical O395) in mucus using single cell tracking in unprocessed porcine intestinal mucus. We determined that V. cholerae is able to penetrate mucus using flagellar motility and that alkaline pH increases swimming speed, and consequently, improves mucus penetration. Microrheological measurements indicate that changes in pH between 6 and 8 (the physiological range for the human small intestine) had little effect on the viscoelastic properties of mucus. Finally, we determined that acidic pH promotes surface attachment by activating the mannose-sensitive haemagglutinin (MshA) pilus in V. cholerae El Tor C6706 without a measurable change in the total cellular concentration of the secondary messenger cyclic dimeric guanosine monophosphate (c-di-GMP). Overall, our results support that pH is an important factor affecting the motile behavior of V. cholerae and its ability to penetrate mucus. Therefore, changes in pH along the human small intestine may play a role in determining the preferred site for V. cholerae during infection. IMPORTANCE The diarrheal disease cholera is still a burden for populations in developing countries with poor sanitation. To develop effective vaccines and prevention strategies against Vibrio cholerae, we must understand the initial steps of infection leading to the colonization of the small intestine. To infect the host and deliver the cholera toxin, V. cholerae has to penetrate the mucus layer protecting the intestinal tissues. However, the interaction of V. cholerae with intestinal mucus has not been extensively investigated. In this report, we demonstrated using single cell tracking that V. cholerae is able to penetrate intestinal mucus using flagellar motility. In addition, we observed that alkaline pH improves the ability of V. cholerae to penetrate mucus. This finding has important implications for understanding the dynamics of infection because pH varies significantly along the small intestine, between individuals, and between species. Blocking mucus penetration by interfering with flagellar motility in V. cholerae, reinforcing the mucosa, controlling intestinal pH, or manipulating the intestinal microbiome, will offer new strategies to fight cholera.

10 THE ROLE OF DIETARY L-SERINE IN THE REGULATION OF INTESTINAL MUCUS BARRIER DURING INFLAMMATION

2020 ◽  
Vol 26 (Supplement_1) ◽  
pp. S42-S42
Author(s):  
Kohei Sugihara ◽  
Nobuhiko Kamada
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Gut Microbiota ◽  
Control Diet ◽  
Bacterial Strains ◽  
Germ Free ◽  
Intestinal Mucus ◽  
Gnotobiotic Mice ◽  
Mucus Barrier

Abstract Background Recent accumulating evidence suggests that amino acids have crucial roles in the maintenance of intestinal homeostasis. In inflammatory bowel disease (IBD), amino acid metabolism is changed in both host and the gut microbiota. Among amino acids, L-serine plays a central role in several metabolic processes that are essential for the growth and survival of both mammalian and bacterial cells. However, the role of L-serine in intestinal homeostasis and IBD remains incompletely understood. In this study, we investigated the effect of dietary L-serine on intestinal inflammation in a murine model of colitis. Methods Specific pathogen-free (SPF) mice were fed either a control diet (amino acid-based diet) or an L-serine-deficient diet (SDD). Colitis was induced by the treatment of dextran sodium sulfate (DSS). The gut microbiome was analyzed by 16S rRNA sequencing. We also evaluate the effect of dietary L-serine in germ-free mice and gnotobiotic mice that were colonized by a consortium of non-mucolytic bacterial strains or the consortium plus mucolytic bacterial strains. Results We found that the SDD exacerbated experimental colitis in SPF mice. However, the severity of colitis in SDD-fed mice was comparable to control diet-fed mice in germ-free condition, suggesting that the gut microbiota is required for exacerbation of colitis caused by the restriction of dietary L-serine. The gut microbiome analysis revealed that dietary L-serine restriction fosters the blooms of a mucus-degrading bacterium Akkermansia muciniphila and adherent-invasive Escherichia coli in the inflamed gut. Consistent with the expansion of mucolytic bacteria, SDD-fed mice showed a loss of the intestinal mucus layer. Dysfunction of the mucus barrier resulted in increased intestinal permeability, thereby leading to bacterial translocation to the intestinal mucosa, which subsequently increased the severity of colitis. The increased intestinal permeability and subsequent bacterial translocation were observed in SDD-fed gnotobiotic mice that colonized by mucolytic bacteria. In contrast, dietary L-serine restriction did not alter intestinal barrier integrity in gnotobiotic mice that colonized only by non-mucolytic bacteria. Conclusion Our results suggest that dietary L-serine regulates the integrity of the intestinal mucus barrier during inflammation by limiting the expansion of mucus degrading bacteria.

scholarly journals Frontline defenders: goblet cell mediators dictate host-microbe interactions in the intestinal tract during health and disease

2018 ◽  
Vol 314 (3) ◽  
pp. G360-G377 ◽  
Author(s):  
Joannie M. Allaire ◽  
Vijay Morampudi ◽  
Shauna M. Crowley ◽  
Martin Stahl ◽  
Hongbing Yu ◽  
...  
Keyword(s):  
Host Defense ◽  
Current Evidence ◽  
Gi Tract ◽  
Intestinal Mucus ◽  
Mucin 2 ◽  
Microbe Interactions ◽  
Noxious Stimuli ◽  
Sense And Respond ◽  
Mucus Barrier ◽  
Host Microbe Interactions

Goblet cells (GCs) are the predominant secretory epithelial cells lining the luminal surface of the mammalian gastrointestinal (GI) tract. Best known for their apical release of mucin 2 (Muc2), which is critical for the formation of the intestinal mucus barrier, GCs have often been overlooked for their active contributions to intestinal protection and host defense. In part, this oversight reflects the limited tools available to study their function but also because GCs have long been viewed as relatively passive players in promoting intestinal homeostasis and host defense. In light of recent studies, this perspective has shifted, as current evidence suggests that Muc2 as well as other GC mediators are actively released into the lumen to defend the host when the GI tract is challenged by noxious stimuli. The ability of GCs to sense and respond to danger signals, such as bacterial pathogens, has recently been linked to inflammasome signaling, potentially intrinsic to the GCs themselves. Moreover, further work suggests that GCs release Muc2, as well as other mediators, to modulate the composition of the gut microbiome, leading to both the expansion as well as the depletion of specific gut microbes. This review will focus on the mechanisms by which GCs actively defend the host from noxious stimuli, as well as describe advanced technologies and new approaches by which their responses can be addressed. Taken together, we will highlight current insights into this understudied, yet critical, aspect of intestinal mucosal protection and its role in promoting gut defense and homeostasis.

scholarly journals Sugar-mediated regulation of a c-di-GMP phosphodiesterase in Vibrio cholerae

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Kyoo Heo ◽  
Young-Ha Park ◽  
Kyung-Ah Lee ◽  
Joonwon Kim ◽  
Hyeong-In Ham ◽  
...  
Keyword(s):  
Vibrio Cholerae ◽  
Biofilm Formation ◽  
Carbon Sources ◽  
Phosphotransferase System ◽  
Host Colonization ◽  
Host Immune Responses ◽  
Gut Colonization ◽  
Host Diet ◽  
Underlying Mechanisms ◽  
Cyclic Dinucleotide

AbstractBiofilm formation protects bacteria from stresses including antibiotics and host immune responses. Carbon sources can modulate biofilm formation and host colonization in Vibrio cholerae, but the underlying mechanisms remain unclear. Here, we show that EIIAGlc, a component of the phosphoenolpyruvate (PEP):carbohydrate phosphotransferase system (PTS), regulates the intracellular concentration of the cyclic dinucleotide c-di-GMP, and thus biofilm formation. The availability of preferred sugars such as glucose affects EIIAGlc phosphorylation state, which in turn modulates the interaction of EIIAGlc with a c-di-GMP phosphodiesterase (hereafter referred to as PdeS). In a Drosophila model of V. cholerae infection, sugars in the host diet regulate gut colonization in a manner dependent on the PdeS-EIIAGlc interaction. Our results shed light into the mechanisms by which some nutrients regulate biofilm formation and host colonization.

scholarly journals Spatiotemporal Analysis of Acid Adaptation-Mediated Vibrio cholerae Hyperinfectivity

2004 ◽  
Vol 72 (4) ◽  
pp. 2405-2407 ◽  
Author(s):  
Michael J. Angelichio ◽  
D. Scott Merrell ◽  
Andrew Camilli
Keyword(s):  
Small Intestine ◽  
Vibrio Cholerae ◽  
Spatiotemporal Analysis ◽  
Rapid Onset ◽  
Multiplication Rate ◽  
Acid Adaptation ◽  
Infant Mouse ◽  
Mouse Intestine ◽  
Kinetics Of ◽  
Transcriptional Induction

ABSTRACT Acid adaptation has previously been shown to increase the infectivity of Vibrio cholerae in the infant mouse model. To better understand this phenomenon, we monitored the spatial distribution and temporal changes in the ratios of acid-adapted cells to unadapted V. cholerae cells in the small intestine, as well as the timing of virulence factor expression. We found that the competitive advantage afforded by acid adaptation does not become manifest until greater than 3 h postinfection; thus, acid adaptation does not increase V. cholerae passage through the gastric acid barrier. Additionally, acid-adapted and unadapted V. cholerae cells colonize the same sections of the small intestine and show similar kinetics of transcriptional induction of the virulence genes tcpA and ctxA. These studies suggest that the increased infectivity of acid-adapted V. cholerae is due to a more rapid onset of multiplication and/or to an increased multiplication rate within the infant mouse intestine.

scholarly journals Oral Immunogenicity in Mice and Sows of Enterotoxigenic Escherichia Coli Outer-Membrane Vesicles Incorporated into Zein-Based Nanoparticles

Vaccines ◽  
2019 ◽  
Vol 8 (1) ◽  
pp. 11 ◽  
Author(s):  
Jose Matías ◽  
Ana Brotons ◽  
Santiago Cenoz ◽  
Isidoro Pérez ◽  
Muthanna Abdulkarim ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Outer Membrane ◽  
Membrane Vesicles ◽  
Outer Membrane Vesicles ◽  
Enterotoxigenic Escherichia Coli ◽  
Protective Capacity ◽  
Intestinal Mucus ◽  
Suckling Piglets ◽  
Specific Igg ◽  
Mucus Barrier

Enterotoxigenic Escherichia coli (ETEC) strains are a major cause of illness and death in neonatal and recently weaned pigs. The immune protection of the piglets derives from maternal colostrum, since this species does not receive maternal antibodies through the placenta. In the present study, outer membrane vesicles (OMVs) obtained from main ETEC strains involved in piglet infection (F4 and F18 serotypes), encapsulated into zein nanoparticles coated with Gantrez®® AN-mannosamine conjugate, were used to orally immunize mice and pregnant sows. Loaded nanoparticles were homogeneous and spherical in a shape, with a size of 220–280 nm. The diffusion of nanoparticles through porcine intestinal mucus barrier was assessed by a Multiple Particle Tracking technique, showing that these particles were able to diffuse efficiently (1.3% diffusion coefficient), validating their oral use. BALB/c mice were either orally immunized with free OMVs or encapsulated into nanoparticles (100 µg OMVs/mouse). Results indicated that a single dose of loaded nanoparticles was able to elicit higher levels of serum specific IgG1, IgG2a and IgA, as well as intestinal IgA, with respect to the free antigens. In addition, nanoparticles induced an increase in levels of IL-2, IL-4 and IFN-γ with respect to the administration of free OMVs. Orally immunized pregnant sows with the same formulation elicited colostrum-, serum- (IgG, IgA or IgM) and fecal- (IgA) specific antibodies and, what is most relevant, offspring suckling piglets presented specific IgG in serum. Further studies are needed to determine the infection protective capacity of this new oral subunit vaccine

scholarly journals Rotavirus Reprograms Multiple Interferon Receptors and Restricts Their Intestinal Antiviral and Inflammatory Functions

2020 ◽  
Vol 94 (6) ◽  
Author(s):  
Adrish Sen ◽  
Nima D. Namsa ◽  
Ningguo Feng ◽  
Harry B. Greenberg
Keyword(s):  
Small Intestine ◽  
Small Bowel ◽  
Inflammatory Cytokines ◽  
Host Species ◽  
Intestinal Cell ◽  
Intestinal Damage ◽  
Range Restriction ◽  
Severe Diarrhea ◽  
Stat1 Signaling ◽  
Bystander Cells

ABSTRACT Rotaviruses (RV) cause acute severe diarrhea in the absence of substantial intestinal inflammation. They are also highly infectious in their homologous host species. The replication capacity of RV in the small bowel is substantially due to its ability to inhibit different types of interferons (IFNs). Here, we found that during RV infection in vitro, both virus-infected and uninfected bystander cells resist STAT1 phosphorylation and interferon regulatory factor 7 (IRF7) induction in response to exogenous interferon (IFN). Functionally, cellular transcription in response to stimulation with IFN, but not intracellular double-stranded RNA (dsRNA), was inhibited by RV. Further, IFNAR1 stimulation during RV infection significantly repressed a set of virus-induced transcripts. Regulation of IFN signaling in vivo was studied in suckling mice using the highly infectious murine EW RV strain. Kinetic studies indicated that sustained EW RV replication and IFN induction in the small intestine are accompanied by significant decreases in IFN-stimulated transcripts. Lipopolysaccharide (LPS)-mediated intestinal damage, driven by STAT1-induced inflammation, was also prevented in EW RV-infected mice. Remarkably, by ectopically stimulating either IFNAR1 or IFNGR1 in EW RV-infected mice, we could eliminate several intestinal antiviral and inflammatory transcriptional responses to RV. In contrast to infection with homologous RV, infection with a STAT1-sensitive heterologous RV strain induced IFN-stimulated transcripts, inflammatory cytokines, and intestinal expression of STAT1-pY701. Finally, RV strain-specific STAT1 regulation also likely determines the intestinal activation of multiple caspases. The simian RRV strain, but not murine EW RV, uniquely triggers the cleavage of both extrinsic and intrinsic caspases (caspases 8, 9, and 3) in a STAT1-mediated manner. Collectively, our findings reveal efficient reprograming of multiple IFN receptors toward a negative-feedback mode of signaling, accompanied by suppression of IFN-mediated antiviral, apoptotic, and inflammatory functions, during natural RV intestinal infection. IMPORTANCE Rotavirus is a highly infectious pathogen that causes severe diarrhea. Replication of RV in the small intestine is restricted to homologous host species, and host range restriction is substantially determined by the interferon response. In this study, we demonstrate that during infection, RV bystander cells resist exogenous IFN-mediated STAT1 signaling and transcription. In a suckling mouse model, ectopically stimulating different intestinal interferon receptors during RV infection eliminates several innate and inflammatory antiviral responses. Different intestinal inflammatory cytokines were also suppressed by homologous RV, as was intestinal damage in response to endotoxin. The ability of RV to suppress IFN-mediated receptors likely impacts intestinal cell homeostasis, as the cleavage of multiple intestinal caspases during RV infection is mediated by the IFN-STAT1 signaling pathway. Together, our results provide a mechanism underlying both the remarkable interferon resistance of homologous RV and its ability to prevent substantial inflammatory damage to the small bowel.

scholarly journals Niche adaptation limits bacteriophage predation of Vibrio cholerae in a nutrient-poor aquatic environment

2019 ◽  
Vol 116 (5) ◽  
pp. 1627-1632 ◽  
Author(s):  
Cecilia A. Silva-Valenzuela ◽  
Andrew Camilli
Keyword(s):  
Small Intestine ◽  
Vibrio Cholerae ◽  
Strong Evidence ◽  
Biological Entity ◽  
Aquatic Environments ◽  
Estuarine Water ◽  
Human Small Intestine ◽  
Niche Adaptation ◽  
Adaptation Limits ◽  
Potential Use

Vibrio cholerae, the causative agent of cholera, has reservoirs in fresh and brackish water where it interacts with virulent bacteriophages. Phages are the most abundant biological entity on earth and coevolve with bacteria. It was reported that concentrations of phage and V. cholerae inversely correlate in aquatic reservoirs and in the human small intestine, and therefore that phages may quench cholera outbreaks. Although there is strong evidence for phage predation in cholera patients, evidence is lacking for phage predation of V. cholerae in aquatic environments. Here, we used three virulent phages, ICP1, ICP2, and ICP3, commonly shed by cholera patients in Bangladesh, as models to understand the predation dynamics in microcosms simulating aquatic environments. None of the phages were capable of predation in fresh water, and only ICP1 was able to prey on V. cholerae in estuarine water due to a requirement for salt. We conclude that ICP2 and ICP3 are better adapted for predation in a nutrient rich environment. Our results point to the evolution of niche-specific predation by V. cholerae-specific virulent phages, which complicates their use in predicting or monitoring cholera outbreaks as well as their potential use in reducing aquatic reservoirs of V. cholerae in endemic areas.

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