Crash landing of Vibrio cholerae by MSHA pili-assisted braking and anchoring in a viscoelastic environment
- Tianjin University, China
- Huazhong University of Science and Technology, China
- University of Bristol, United Kingdom
- University of Tsukuba, Japan
Abstract
Mannose-sensitive hemagglutinin (MSHA) pili and flagellum are critical for the surface attachment of Vibrio cholerae, the first step of V. cholerae colonization on host surfaces. However, the cell landing mechanism remains largely unknown, particularly in viscoelastic environments such as the mucus layers of intestines. Here, combining the cysteine-substitution-based labelling method with single-cell tracking techniques, we quantitatively characterized the landing of V. cholerae by directly observing both pili and flagellum of cells in a viscoelastic non-Newtonian solution consisting of 2% Luria-Bertani and 1% methylcellulose (LB+MC). The results show that MSHA pili are evenly distributed along the cell length and can stick to surfaces at any point along the filament. With such properties, MSHA pili are observed to act as a brake and anchor during cell landing which include three phases: running, lingering, and attaching. Importantly, loss of MSHA pili results in a more dramatic increase in mean path length in LB+MC than in 2% LB only or in 20% Ficoll solutions, indicating that the role of MSHA pili during cell landing is more apparent in viscoelastic non-Newtonian fluids than viscous Newtonian ones. Our work provides a detailed picture of the landing dynamics of V. cholerae under viscoelastic conditions, which can provide insights into ways to better control V. cholerae infections in real mucus-like environment.
Data availability
All data generated or analysed during this study are included in the manuscript and supporting files. Source data files have been provided for Figures 1-6.
Article and author information
Author details
Funding
National Key R and D Program of China (2018YFA0902102)
- Kun Zhao
National Natural Science Foundation of China (31770132)
- Zhi Liu
National Natural Science Foundation of China (81572050)
- Zhi Liu
National Natural Science Foundation of China (21621004)
- Kun Zhao
University of Bristol (Vice-Chancellor's Fellowship)
- Rachel R Bennett
Grant in aid for Young Scientists (17K15410)
- Andrew S Utada
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
Ethics
Animal experimentation: All mice received the humane care and the experimental protocols were carried out in accordance with the Guide for the Care and Use of Laboratory Animals, Huazhong University of Science and Technology, as approved by the Animal Care Committee of Hubei Province.
Reviewing Editor
- Raymond E Goldstein, University of Cambridge, United Kingdom
Publication history
- Received: July 2, 2020
- Accepted: July 1, 2021
- Accepted Manuscript published: July 2, 2021 (version 1)
- Version of Record published: July 15, 2021 (version 2)
Copyright
© 2021, Zhang et al.
This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.
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Crash landing of Vibrio cholerae by MSHA pili-assisted braking and anchoring in a viscoelastic environment
eLife 10:e60655.
https://doi.org/10.7554/eLife.60655
Further reading
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- Medicine
- Microbiology and Infectious Disease
Background:
Severe pneumonia is one of the common acute diseases caused by pathogenic bacteria infection, especially by pathogenic bacteria, leading to sepsis with a high morbidity and mortality rate. However, the existing bacteria cultivation method cannot satisfy current clinical needs requiring rapid identification of bacteria strain for antibiotic selection. Therefore, developing a sensitive liquid biopsy system demonstrates the enormous value of detecting pathogenic bacterium species in pneumonia patients.
Methods:
In this study, we developed a tool named Species-Specific Bacterial Detector (SSBD, pronounce as "speed") for detecting selected bacterium. Newly designed diagnostic tools combining specific DNA-tag screened by our algorithm and CRISPR/Cas12a, which were first tested in the lab to confirm the accuracy, followed by validating its specificity and sensitivity via applying on bronchoalveolar lavage fluid (BALF) from pneumonia patients. In the validation I stage, we compared the SSBD results with traditional cultivation results. In the validation II stage, a randomized and controlled clinical trial was completed at the ICU of Nanjing Drum Tower Hospital to evaluate the benefit SSBD brought to the treatment.
Results:
In the validation stage I, 77 BALF samples were tested, and SSBD could identify designated organisms in 4 hours with almost 100% sensitivity and over 87% specific rate. In validation stage II, the SSBD results were obtained in 4 hours, leading to better APACHE II scores (p=0.0035, ANOVA test). Based on the results acquired by SSBD, cultivation results could deviate from the real pathogenic situation with polymicrobial infections. In addition, nosocomial infections were found widely in ICU, which should deserve more attention.
Funding:
National Natural Science Foundation of China. The National Key Scientific Instrument and Equipment Development Project. Project number: 81927808.
Clinical trial:
This study was registered at ClinicalTrilas.gov (NCT04178382).
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- Biochemistry and Chemical Biology
- Microbiology and Infectious Disease
Oxidative stress-mediated formation of protein hydroperoxides can induce irreversible fragmentation of the peptide backbone and accumulation of cross-linked protein aggregates, leading to cellular toxicity, dysfunction, and death. However, how bacteria protect themselves from damages caused by protein hydroperoxidation is unknown. Here, we show that YjbI, a group II truncated haemoglobin from Bacillus subtilis, prevents oxidative aggregation of cell-surface proteins by its protein hydroperoxide peroxidase-like activity, which removes hydroperoxide groups from oxidised proteins. Disruption of the yjbI gene in B. subtilis lowered biofilm water repellence, which associated with the cross-linked aggregation of the biofilm matrix protein TasA. YjbI was localised to the cell surface or the biofilm matrix, and the sensitivity of planktonically grown cells to generators of reactive oxygen species was significantly increased upon yjbI disruption, suggesting that YjbI pleiotropically protects labile cell-surface proteins from oxidative damage. YjbI removed hydroperoxide residues from the model oxidised protein substrate bovine serum albumin and biofilm component TasA, preventing oxidative aggregation in vitro. Furthermore, the replacement of Tyr63 near the haem of YjbI with phenylalanine resulted in the loss of its protein peroxidase-like activity, and the mutant gene failed to rescue biofilm water repellency and resistance to oxidative stress induced by hypochlorous acid in the yjbI-deficient strain. These findings provide new insights into the role of truncated haemoglobin and the importance of hydroperoxide removal from proteins in the survival of aerobic bacteria.
