Outer Membrane Vesicles of Helicobacter pylori TK1402 are Involved in Biofilm Formation

Yonezawa, Hideo; Osaki, Takako; Kurata, Satoru; Fukuda, Minoru; Kawakami, Hayato; Ochiai, Kuniyasu; Hanawa, Tomoko; Kamiya, Shigeru

doi:10.1186/1471-2180-9-197

Cited by 224 publications

(193 citation statements)

References 38 publications

(50 reference statements)

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“…In several pathogenic organisms GAPDH is also secreted and promotes adherence to host cells (Egea et al, 2007;Tunio et al, 2010); a function also stimulated by the OMVs of some pathogens (e.g. Yonezawa et al, 2009). Potentially, M. xanthus may secrete GAPDH alongside mxOMVs in order to promote fusion of mxOMVs with recipient cells, thereby enhancing their predatory activity.…”

Section: A G L Evans and Othersmentioning

confidence: 99%

Predatory activity of Myxococcus xanthus outer-membrane vesicles and properties of their hydrolase cargo

et al. 2012

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The deltaproteobacterium Myxococcus xanthus predates upon members of the soil microbial community by secreting digestive factors and lysing prey cells. Like other Gram-negative bacteria, M. xanthus produces outer membrane vesicles (OMVs), and we show here that M. xanthus OMVs are able to kill Escherichia coli cells. The OMVs of M. xanthus were found to contain active proteases, phosphatases, other hydrolases and secondary metabolites. Alkaline phosphatase activity was found to be almost exclusively associated with OMVs, implying that there is active targeting of phosphatases into OMVs, while other OMV components appear to be packaged passively. The kinetic properties of OMV alkaline phosphatase suggest that there may have been evolutionary adaptation of OMV enzymes to a relatively indiscriminate mode of action, consistent with a role in predation. In addition, the observed regulation of production, and fragility of OMV activity, may protect OMV-producing cells from exploitation by M. xanthus cheating genotypes and/or other competitors. Killing of E. coli by M. xanthus OMVs was enhanced by the addition of a fusogenic enzyme (glyceraldehyde-3-phosphate dehydrogenase; GAPDH), which triggers fusion of vesicles with target membranes within eukaryotic cells. This suggests that the mechanism of prey killing involves OMV fusion with the E. coli outer membrane. M. xanthus secretes GAPDH, which could potentially modulate the fusion of co-secreted OMVs with prey organisms in nature, enhancing their predatory activity.

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Section: A G L Evans and Othersmentioning

confidence: 99%

Predatory activity of Myxococcus xanthus outer-membrane vesicles and properties of their hydrolase cargo

et al. 2012

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“…Further investigation of the EPS matrix demonstrated the presence of extracellular DNA (eDNA); however, in contrast to what has been shown for other Gram-negative species, eDNA does not appear to play a structural role in H. pylori biofilms (46). An increased number of outer membrane vesicles (OMVs) are associated with H. pylori found within a biofilm compared to planktonic bacteria, suggesting a potential link between OMV production and biofilm formation (47,48). Interestingly, OMVs have been observed in association with other Gram-negative biofilms, such as those formed by Pseudomonas aeruginosa (49).…”

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confidence: 99%

Characterization of Key Helicobacter pylori Regulators Identifies a Role for ArsRS in Biofilm Formation

et al. 2016

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Helicobacter pylori must be able to rapidly respond to fluctuating conditions within the stomach. Despite this need for constant adaptation, H. pylori encodes few regulatory proteins. Of the identified regulators, the ferric uptake regulator (Fur), the nickel response regulator (NikR), and the two-component acid response system (ArsRS) are each paramount to the success of this pathogen. While numerous studies have individually examined these regulatory proteins, little is known about their combined effect. Therefore, we constructed a series of isogenic mutant strains that contained all possible single, double, and triple regulatory mutations in Fur, NikR, and ArsS. A growth curve analysis revealed minor variation in growth kinetics across the strains; these were most pronounced in the triple mutant and in strains lacking ArsS. Visual analysis showed that strains lacking ArsS formed large aggregates and a biofilm-like matrix at the air-liquid interface. Biofilm quantification using crystal violet assays and visualization via scanning electron microscopy (SEM) showed that all strains lacking ArsS or containing a nonphosphorylatable form of ArsR (ArsR-D52N mutant) formed significantly more biofilm than the wild-type strain. Molecular characterization of biofilm formation showed that strains containing mutations in the ArsRS pathway displayed increased levels of cell aggregation and adherence, both of which are key to biofilm development. Furthermore, SEM analysis revealed prevalent coccoid cells and extracellular matrix formation in the ArsR-D52N, ⌬nikR ⌬arsS, and ⌬fur ⌬nikR ⌬arsS mutant strains, suggesting that these strains may have an exacerbated stress response that further contributes to biofilm formation. Thus, H. pylori ArsRS has a previously unrecognized role in biofilm formation. IMPORTANCEDespite a paucity of regulatory proteins, adaptation is key to the survival of H. pylori within the stomach. While prior studies have focused on individual regulatory proteins, such as Fur, NikR, and ArsRS, few studies have examined the combined effect of these factors. Analysis of isogenic mutant strains that contained all possible single, double, and triple regulatory mutations in Fur, NikR, and ArsS revealed a previously unrecognized role for the acid-responsive two-component system ArsRS in biofilm formation.

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“…H. pylori strains ATCC 49503 and TK1402 were used in this study. The latter strain is a clinical isolate from a Japanese patient, which has been used in previous studies (Yamaguchi et al, 2003;Yonezawa et al, 2009). All strains were stored at 270 uC in Brucella broth (Becton Dickinson) with 20 % (v/v) glycerol.…”

Section: Methodsmentioning

confidence: 99%

Destructive effects of butyrate on the cell envelope of Helicobacter pylori

Yonezawa

Osaki

Hanawa

et al. 2012

Journal of Medical Microbiology

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Helicobacter pylori can be found in the oral cavity and is mostly detected by the use of PCR techniques. Growth of H. pylori is influenced by various factors in the mouth, such as the oral microflora, saliva and other antimicrobial substances, all of which make colonization of the oral cavity by H. pylori difficult. In the present study, we analysed the effect of the cell supernatant of a representative periodontal bacterium Porphyromonas gingivalis on H. pylori and found that the cell supernatant destroyed the H. pylori cell envelope. As P. gingivalis produces butyric acid, we focused our research on the effects of butyrate and found that it significantly inhibited the growth of H. pylori. H. pylori cytoplasmic proteins and DNA were detected in the extracellular environment after treatment with butyrate, suggesting that the integrity of the cell envelope was compromised and indicating that butyrate has a bactericidal effect on H. pylori. In addition, levels of extracellular H. pylori DNA increased following treatment with the cell supernatant of butyric acid-producing bacteria, indicating that the cell supernatant also has a bactericidal effect and that this may be due to its butyric acid content. In conclusion, butyric acid-producing bacteria may play a role in affecting H. pylori colonization of the oral cavity.

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Outer Membrane Vesicles of Helicobacter pylori TK1402 are Involved in Biofilm Formation

Cited by 224 publications

References 38 publications

Predatory activity of Myxococcus xanthus outer-membrane vesicles and properties of their hydrolase cargo

Predatory activity of Myxococcus xanthus outer-membrane vesicles and properties of their hydrolase cargo

Characterization of Key Helicobacter pylori Regulators Identifies a Role for ArsRS in Biofilm Formation

Destructive effects of butyrate on the cell envelope of Helicobacter pylori

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