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Brannon JR, Reasoner SA, Bermudez TA, Dunigan TL, Wiebe MA, Beebout CJ, Ross T, Bamidele A, Hadjifrangiskou M. Mapping Niche-specific Two-Component System Requirements in Uropathogenic Escherichia coli. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.05.23.541942. [PMID: 37292752 PMCID: PMC10245908 DOI: 10.1101/2023.05.23.541942] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Sensory systems allow pathogens to differentiate between different niches and respond to stimuli within them. A major mechanism through which bacteria sense and respond to stimuli in their surroundings is two-component systems (TCSs). TCSs allow for the detection of multiple stimuli to lead to a highly controlled and rapid change in gene expression. Here, we provide a comprehensive list of TCSs important for the pathogenesis of uropathogenic Escherichia coli (UPEC). UPEC accounts for >75% of urinary tract infections (UTIs) worldwide. UTIs are most prevalent among people assigned female at birth, with the vagina becoming colonized by UPEC in addition to the gut and the bladder. In the bladder, adherence to the urothelium triggers E. coli invasion of bladder cells and an intracellular pathogenic cascade. Intracellular E. coli are safely hidden from host neutrophils, competition from the microbiota, and antibiotics that kill extracellular E. coli. To survive in these intimately connected, yet physiologically diverse niches E. coli must rapidly coordinate metabolic and virulence systems in response to the distinct stimuli encountered in each environment. We hypothesized that specific TCSs allow UPEC to sense these diverse environments encountered during infection with built-in redundant safeguards. Here, we created a library of isogenic TCS deletion mutants that we leveraged to map distinct TCS contributions to infection. We identify - for the first time - a comprehensive panel of UPEC TCSs that are critical for infection of the genitourinary tract and report that the TCSs mediating colonization of the bladder, kidneys, or vagina are distinct.
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Affiliation(s)
- John R. Brannon
- Department of Pathology, Microbiology & Immunology, Division of Molecular Pathogenesis, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Seth A. Reasoner
- Department of Pathology, Microbiology & Immunology, Division of Molecular Pathogenesis, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Tomas A. Bermudez
- Department of Pathology, Microbiology & Immunology, Division of Molecular Pathogenesis, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Taryn L. Dunigan
- Department of Pathology, Microbiology & Immunology, Division of Molecular Pathogenesis, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Michelle A. Wiebe
- Department of Pathology, Microbiology & Immunology, Division of Molecular Pathogenesis, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Connor J. Beebout
- Department of Pathology, Microbiology & Immunology, Division of Molecular Pathogenesis, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Tamia Ross
- Department of Pathology, Microbiology & Immunology, Division of Molecular Pathogenesis, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Adebisi Bamidele
- Department of Pathology, Microbiology & Immunology, Division of Molecular Pathogenesis, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Maria Hadjifrangiskou
- Department of Pathology, Microbiology & Immunology, Division of Molecular Pathogenesis, Vanderbilt University Medical Center, Nashville, TN, USA
- Department of Urology, Vanderbilt University Medical Center, Nashville, TN, USA
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2
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Voliotis M, Rosko J, Pilizota T, Liverpool TB. Steady-state running rate sets the speed and accuracy of accumulation of swimming bacteria. Biophys J 2022; 121:3435-3444. [PMID: 36045575 PMCID: PMC9515231 DOI: 10.1016/j.bpj.2022.08.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Revised: 07/31/2022] [Accepted: 08/15/2022] [Indexed: 11/21/2022] Open
Abstract
We study the chemotaxis of a population of genetically identical swimming bacteria undergoing run and tumble dynamics driven by stochastic switching between clockwise and counterclockwise rotation of the flagellar rotary system, where the steady-state rate of the switching changes in different environments. Understanding chemotaxis quantitatively requires that one links the measured steady-state switching rates of the rotary system, as well as the directional changes of individual swimming bacteria in a gradient of chemoattractant/repellant, to the efficiency of a population of bacteria in moving up/down the gradient. Here we achieve this by using a probabilistic model, parametrized with our experimental data, and show that the response of a population to the gradient is complex. We find the changes to the steady-state switching rate in the absence of gradients affect the average speed of the swimming bacterial population response as well as the width of the distribution. Both must be taken into account when optimizing the overall response of the population in complex environments.
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Affiliation(s)
- Margaritis Voliotis
- College of Engineering, Mathematics and Physical Sciences, University of Exeter, Exeter, United Kingdom.
| | - Jerko Rosko
- School of Life Sciences, University of Warwick, Coventry, United Kingdom
| | - Teuta Pilizota
- Centre for Synthetic and Systems Biology, University of Edinburgh, Edinburgh, United Kingdom.
| | - Tanniemola B Liverpool
- School of Mathematics, University of Bristol, Bristol, United Kingdom; BrisSynBio, Life Sciences Building, University of Bristol, Bristol, United Kingdom.
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3
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Abd El Ghany M, Barquist L, Clare S, Brandt C, Mayho M, Joffre´ E, Sjöling Å, Turner AK, Klena JD, Kingsley RA, Hill-Cawthorne GA, Dougan G, Pickard D. Functional analysis of colonization factor antigen I positive enterotoxigenic Escherichia coli identifies genes implicated in survival in water and host colonization. Microb Genom 2021; 7:000554. [PMID: 34110281 PMCID: PMC8461466 DOI: 10.1099/mgen.0.000554] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Accepted: 03/09/2021] [Indexed: 12/13/2022] Open
Abstract
Enterotoxigenic Escherichia coli (ETEC) expressing the colonization pili CFA/I are common causes of diarrhoeal infections in humans. Here, we use a combination of transposon mutagenesis and transcriptomic analysis to identify genes and pathways that contribute to ETEC persistence in water environments and colonization of a mammalian host. ETEC persisting in water exhibit a distinct RNA expression profile from those growing in richer media. Multiple pathways were identified that contribute to water survival, including lipopolysaccharide biosynthesis and stress response regulons. The analysis also indicated that ETEC growing in vivo in mice encounter a bottleneck driving down the diversity of colonizing ETEC populations.
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Affiliation(s)
- Moataz Abd El Ghany
- The Westmead Institute for Medical Research, University of Sydney, Sydney, Australia
- Marie Bashir Institute for Infectious Diseases and Biosecurity, University of Sydney, Sydney, Australia
- The Westmead Clinical School, Faculty of Medicine and Health, University of Sydney, Sydney, Australia
- King Abdullah University of Science and Technology (KAUST), Thuwal, Kingdom of Saudi Arabia
| | - Lars Barquist
- Helmholtz Institute for RNA-based Infection Research (HIRI), Helmholtz Centre for Infection Research (HZI), Würzburg, Germany
- Faculty of Medicine, University of Würzburg, Würzburg, Germany
| | - Simon Clare
- The Wellcome Trust Sanger Institute (WTSI), the Wellcome Trust Genome Campus, Hinxton, Cambridge, UK
| | - Cordelia Brandt
- The Wellcome Trust Sanger Institute (WTSI), the Wellcome Trust Genome Campus, Hinxton, Cambridge, UK
| | - Matthew Mayho
- The Wellcome Trust Sanger Institute (WTSI), the Wellcome Trust Genome Campus, Hinxton, Cambridge, UK
| | - Enrique Joffre´
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden
| | - Åsa Sjöling
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden
| | - A. Keith Turner
- The Wellcome Trust Sanger Institute (WTSI), the Wellcome Trust Genome Campus, Hinxton, Cambridge, UK
- Quadram Institute Bioscience, Norwich Research Park, Norwich, UK
| | - John D. Klena
- Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | - Robert A. Kingsley
- The Wellcome Trust Sanger Institute (WTSI), the Wellcome Trust Genome Campus, Hinxton, Cambridge, UK
- Quadram Institute Bioscience, Norwich Research Park, Norwich, UK
| | | | - Gordon Dougan
- The Wellcome Trust Sanger Institute (WTSI), the Wellcome Trust Genome Campus, Hinxton, Cambridge, UK
- Department of Medicine, University of Cambridge, Cambridge, UK
| | - Derek Pickard
- The Wellcome Trust Sanger Institute (WTSI), the Wellcome Trust Genome Campus, Hinxton, Cambridge, UK
- Department of Medicine, University of Cambridge, Cambridge, UK
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4
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Ferreira JL, Coleman I, Addison ML, Zachs T, Quigley BL, Wuichet K, Beeby M. The "Jack-of-all-Trades" Flagellum From Salmonella and E. coli Was Horizontally Acquired From an Ancestral β-Proteobacterium. Front Microbiol 2021; 12:643180. [PMID: 33859630 PMCID: PMC8042155 DOI: 10.3389/fmicb.2021.643180] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Accepted: 03/05/2021] [Indexed: 11/24/2022] Open
Abstract
The γ-proteobacteria are a group of diverse bacteria including pathogenic Escherichia, Salmonella, Vibrio, and Pseudomonas species. The majority swim in liquids with polar, sodium-driven flagella and swarm on surfaces with lateral, non-chemotactic flagella. Notable exceptions are the enteric Enterobacteriaceae such as Salmonella and E. coli. Many of the well-studied Enterobacteriaceae are gut bacteria that both swim and swarm with the same proton-driven peritrichous flagella. How different flagella evolved in closely related lineages, however, has remained unclear. Here, we describe our phylogenetic finding that Enterobacteriaceae flagella are not native polar or lateral γ-proteobacterial flagella but were horizontally acquired from an ancestral β-proteobacterium. Using electron cryo-tomography and subtomogram averaging, we confirmed that Enterobacteriaceae flagellar motors resemble contemporary β-proteobacterial motors and are distinct to the polar and lateral motors of other γ-proteobacteria. Structural comparisons support a model in which γ-proteobacterial motors have specialized, suggesting that acquisition of a β-proteobacterial flagellum may have been beneficial as a general-purpose motor suitable for adjusting to diverse conditions. This acquisition may have played a role in the development of the enteric lifestyle.
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Affiliation(s)
- Josie L Ferreira
- Department of Life Sciences, Imperial College London, London, United Kingdom
| | - Izaak Coleman
- Department of Life Sciences, Imperial College London, London, United Kingdom
| | - Max L Addison
- Department of Life Sciences, Imperial College London, London, United Kingdom
| | - Tobias Zachs
- Department of Life Sciences, Imperial College London, London, United Kingdom
| | - Bonnie L Quigley
- Department of Life Sciences, Imperial College London, London, United Kingdom
| | - Kristin Wuichet
- Department of Biomedical Informatics, Vanderbilt University Medical Center, Nashville, TN, United States
| | - Morgan Beeby
- Department of Life Sciences, Imperial College London, London, United Kingdom
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5
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Yoon SH, Waters CM. The ever-expanding world of bacterial cyclic oligonucleotide second messengers. Curr Opin Microbiol 2021; 60:96-103. [PMID: 33640793 DOI: 10.1016/j.mib.2021.01.017] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2020] [Revised: 01/27/2021] [Accepted: 01/30/2021] [Indexed: 01/08/2023]
Abstract
Cyclic dinucleotide (cdN) second messengers are essential for bacteria to sense and adapt to their environment. These signals were first discovered with the identification of 3'-5', 3'-5' cyclic di-GMP (c-di-GMP) in 1987, a second messenger that is now known to be the linchpin signaling pathway modulating bacterial motility and biofilm formation. In the past 15 years, three more cdNs were uncovered: 3'-5', 3'-5' cyclic di-AMP (c-di-AMP) and 3'-5', 3'-5' cyclic GMP-AMP (3',3' cGAMP) in bacteria and 2'-5', 3'-5' cyclic GMP-AMP (2',3' cGAMP) in eukaryotes. We now appreciate that bacteria can synthesize many varieties of cdNs from every ribonucleotide, and even cyclic trinucleotide (ctN) second messengers have been discovered. Here we highlight our current understanding of c-di-GMP and c-di-AMP in bacterial physiology and focus on recent advances in 3',3' cGAMP signaling effectors, its role in bacterial phage response, and the diversity of its synthase family.
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Affiliation(s)
- Soo Hun Yoon
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI, 48824 USA
| | - Christopher M Waters
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI, 48824 USA.
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6
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Bell J, Araujo G, Tang JX. Discovery of oscillations in rotational speed of body-tethered Caulobacter crescentus. Phys Rev E 2021; 102:062416. [PMID: 33466088 DOI: 10.1103/physreve.102.062416] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2018] [Accepted: 11/09/2020] [Indexed: 11/07/2022]
Abstract
Swarmer cells of Caulobacter crescentus have been found to tether to glass at a point on the cell body. The rolling of the freely rotating flagellum near the glass surface causes the cell body to rotate. We describe the discovery of damped oscillations in the rotational speed of these cell bodies. We show that the damped oscillations are robust over multiple cells and that they depend more on the cell's accumulated rotation angle than on time. We also find that their phase is determined by the moment the flagellar motor changes the direction of its rotation. The oscillations occur only for one direction of cell rotation, when the flagellum is in pulling mode. We discuss possible explanations for these oscillations, including fluctuations in flagellar motor torque and periodic changes in flagellar orientation, and illustrate both of these cases using simplified computer models. Finally, we present the hypothesis that the oscillations are the result of fluctuations in the proton motive force, initiated by a sudden change in proton current that occurs when the motor switches rotation direction.
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Affiliation(s)
- Jordan Bell
- Department of Physics, Brown University, Providence, Rhode Island 02912, USA
| | - George Araujo
- Department of Physics, Brown University, Providence, Rhode Island 02912, USA
| | - Jay X Tang
- Department of Physics, Brown University, Providence, Rhode Island 02912, USA
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7
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Johnson S, Fong YH, Deme JC, Furlong EJ, Kuhlen L, Lea SM. Symmetry mismatch in the MS-ring of the bacterial flagellar rotor explains the structural coordination of secretion and rotation. Nat Microbiol 2020; 5:966-975. [PMID: 32284565 PMCID: PMC7320910 DOI: 10.1038/s41564-020-0703-3] [Citation(s) in RCA: 52] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2019] [Accepted: 03/05/2020] [Indexed: 11/14/2022]
Abstract
The bacterial flagellum is a complex self-assembling nanomachine that confers motility to the cell. Despite great variation across species, all flagella are ultimately constructed from a helical propeller that is attached to a motor embedded in the inner membrane. The motor consists of a series of stator units surrounding a central rotor made up of two ring complexes, the MS-ring and the C-ring. Despite many studies, high-resolution structural information is still lacking for the MS-ring of the rotor, and proposed mismatches in stoichiometry between the two rings have long provided a source of confusion for the field. Here, we present structures of the Salmonella MS-ring, revealing a high level of variation in inter- and intrachain symmetry that provides a structural explanation for the ability of the MS-ring to function as a complex and elegant interface between the two main functions of the flagellum-protein secretion and rotation.
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Affiliation(s)
- Steven Johnson
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK
| | - Yu Hang Fong
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK
| | - Justin C Deme
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK
- Central Oxford Structural Molecular Imaging Centre, University of Oxford, Oxford, UK
| | - Emily J Furlong
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK
| | - Lucas Kuhlen
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK
| | - Susan M Lea
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK.
- Central Oxford Structural Molecular Imaging Centre, University of Oxford, Oxford, UK.
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8
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Iyer D, Gulyuk AV, Reddy P, Kirste R, Collazo R, LaJeunesse DR, Ivanisevic A. Behavior of E. coli with Variable Surface Morphology Changes on Charged Semiconductor Interfaces. ACS APPLIED BIO MATERIALS 2019; 2:4044-4051. [PMID: 35021338 PMCID: PMC10167750 DOI: 10.1021/acsabm.9b00573] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Bacterial behavior is often controlled by structural and composition elements of their cell wall. Using genetic mutant strains that change specific aspects of their surface structure, we modified bacterial behavior in response to semiconductor surfaces. We monitored the adhesion, membrane potential, and catalase activity of the Gram-negative bacterium Escherichia coli (E. coli) that were mutant for genes encoding components of their surface architecture, specifically flagella, fimbriae, curli, and components of the lipopolysaccharide membrane, while on gallium nitride (GaN) surfaces with different surface potentials. The bacteria and the semiconductor surface properties were recorded prior to the biofilm studies. The data from the materials and bioassays characterization supports the notion that alteration of the surface structure of the E. coli bacterium resulted in changes to bacterium behavior on the GaN medium. Loss of specific surface structure on the E. coli bacterium reduced its sensitivity to the semiconductor interfaces, while other mutations increase bacterial adhesion when compared to the wild-type control E. coli bacteria. These results demonstrate that bacterial behavior and responses to GaN semiconductor materials can be controlled genetically and can be utilized to tune the fate of living bacteria on GaN surfaces.
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Affiliation(s)
- Divya Iyer
- Department of Nanoscience, Joint School of Nanoscience and Nanoengineering, University of North Carolina-Greensboro, Greensboro, North Carolina 27401, United States
| | - Alexey V. Gulyuk
- Department of Materials Science and Engineering, North Carolina State University, Raleigh, North Carolina 27695, United States
| | - Pramod Reddy
- Adroit Materials, 2054 Kildaire Farm Road, Suite 205, Cary, North Carolina 27518, United States
| | - Ronny Kirste
- Adroit Materials, 2054 Kildaire Farm Road, Suite 205, Cary, North Carolina 27518, United States
| | - Ramon Collazo
- Department of Materials Science and Engineering, North Carolina State University, Raleigh, North Carolina 27695, United States
| | - Dennis R. LaJeunesse
- Department of Nanoscience, Joint School of Nanoscience and Nanoengineering, University of North Carolina-Greensboro, Greensboro, North Carolina 27401, United States
| | - Albena Ivanisevic
- Department of Materials Science and Engineering, North Carolina State University, Raleigh, North Carolina 27695, United States
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9
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Volke DC, Nikel PI. Getting Bacteria in Shape: Synthetic Morphology Approaches for the Design of Efficient Microbial Cell Factories. ACTA ACUST UNITED AC 2018. [DOI: 10.1002/adbi.201800111] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Daniel C. Volke
- The Novo Nordisk Foundation Center for Biosustainability; Technical University of Denmark; Kemitorvet 2800 Kgs. Lyngby Denmark
| | - Pablo I. Nikel
- The Novo Nordisk Foundation Center for Biosustainability; Technical University of Denmark; Kemitorvet 2800 Kgs. Lyngby Denmark
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10
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Dahlquist FW. The Bacterial Flagellar Motor Continues to Amaze. Biophys J 2018; 114:505-506. [PMID: 29414695 DOI: 10.1016/j.bpj.2017.11.3786] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2017] [Accepted: 11/10/2017] [Indexed: 10/18/2022] Open
Affiliation(s)
- Frederick W Dahlquist
- Department of Chemistry and Biochemistry and Department of Molecular, Cellular and Developmental Biology, University of California Santa Barbara, Santa Barbara, California.
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11
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Iida T, Iwata Y, Mohri T, Baba SA, Hirohashi N. A coordinated sequence of distinct flagellar waveforms enables a sharp flagellar turn mediated by squid sperm pH-taxis. Sci Rep 2017; 7:12938. [PMID: 29021593 PMCID: PMC5636881 DOI: 10.1038/s41598-017-13406-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2017] [Accepted: 09/22/2017] [Indexed: 11/20/2022] Open
Abstract
Animal spermatozoa navigate by sensing ambient chemicals to reach the site of fertilization. Generally, such chemicals derive from the female reproductive organs or cells. Exceptionally, squid spermatozoa mutually release and perceive carbon dioxide to form clusters after ejaculation. We previously identified the pH-taxis by which each spermatozoon can execute a sharp turn, but how flagellar dynamics enable this movement remains unknown. Here, we show that initiation of the turn motion requires a swim down a steep proton gradient (a theoretical estimation of ≥0.025 pH/s), crossing a threshold pH value of ~5.5. Time-resolved kinematic analysis revealed that the turn sequence results from the rhythmic exercise of two flagellar motions: a stereotypical flagellar ‘bent-cane’ shape followed by asymmetric wave propagation, which enables a sharp turn in the realm of low Reynolds numbers. This turning episode is terminated by an ‘overshoot’ trajectory that differs from either straight-line motility or turning. As with bidirectional pH-taxes in some bacteria, squid spermatozoa also showed repulsion from strong acid conditions with similar flagellar kinematics as in positive pH-taxis. These findings indicate that squid spermatozoa might have a unique reorientation mechanism, which could be dissimilar to that of classical egg-guided sperm chemotaxis in other marine invertebrates.
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Affiliation(s)
- Tomohiro Iida
- Oki Marine Biological Station, Education and Research Center for Biological Resources, Shimane University, 194 Kamo, Okinoshima-cho, Oki, Shimane, 685-0024, Japan
| | - Yoko Iwata
- Atmosphere and Ocean Research Institute, University of Tokyo, Kashiwa, Japan
| | - Tatsuma Mohri
- Section of Individual Researches, National Institute for Physiological Sciences, National Institutes of Natural Sciences, 5-1 Higashiyama, Myodaiji-cho Okazaki, 444-8787, Japan
| | - Shoji A Baba
- Ochanomizu University, 2-2-1 Otsuka, Tokyo, 112-8610, Japan
| | - Noritaka Hirohashi
- Oki Marine Biological Station, Education and Research Center for Biological Resources, Shimane University, 194 Kamo, Okinoshima-cho, Oki, Shimane, 685-0024, Japan.
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12
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Mongiardini EJ, Quelas JI, Dardis C, Althabegoiti MJ, Lodeiro AR. Transcriptional Control of the Lateral-Flagellar Genes of Bradyrhizobium diazoefficiens. J Bacteriol 2017; 199:e00253-17. [PMID: 28533217 PMCID: PMC5512216 DOI: 10.1128/jb.00253-17] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2017] [Accepted: 05/16/2017] [Indexed: 11/20/2022] Open
Abstract
Bradyrhizobium diazoefficiens, a soybean N2-fixing symbiont, possesses a dual flagellar system comprising a constitutive subpolar flagellum and inducible lateral flagella. Here, we analyzed the genomic organization and biosynthetic regulation of the lateral-flagellar genes. We found that these genes are located in a single genomic cluster, organized in two monocistronic transcriptional units and three operons, one possibly containing an internal transcription start site. Among the monocistronic units is blr6846, homologous to the class IB master regulators of flagellum synthesis in Brucella melitensis and Ensifer meliloti and required for the expression of all the lateral-flagellar genes except lafA2, whose locus encodes a single lateral flagellin. We therefore named blr6846 lafR (lateral-flagellar regulator). Despite its similarity to two-component response regulators and its possession of a phosphorylatable Asp residue, lafR behaved as an orphan response regulator by not requiring phosphorylation at this site. Among the genes induced by lafR is flbTL , a class III regulator. We observed different requirements for FlbTL in the synthesis of each flagellin subunit. Although the accumulation of lafA1, but not lafA2, transcripts required FlbTL, the production of both flagellin polypeptides required FlbTL Moreover, the regulation cascade of this lateral-flagellar regulon appeared to be not as strictly ordered as those found in other bacterial species.IMPORTANCE Bacterial motility seems essential for the free-living style in the environment, and therefore these microorganisms allocate a great deal of their energetic resources to the biosynthesis and functioning of flagella. Despite energetic costs, some bacterial species possess dual flagellar systems, one of which is a primary system normally polar or subpolar, and the other is a secondary, lateral system that is produced only under special circumstances. Bradyrhizobium diazoefficiens, an N2-fixing symbiont of soybean plants, possesses dual flagellar systems, including the lateral system that contributes to swimming in wet soil and competition for nodulation and is expressed under high energy availability, as well as under requirement for high torque by the flagella. The structural organization and transcriptional regulation of the 41 genes that comprise this secondary flagellar system seem adapted to adjust bacterial energy expenditures for motility to the soil's environmental dynamics.
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Affiliation(s)
- Elías J Mongiardini
- Instituto de Biotecnología y Biología Molecular, Facultad de Ciencias Exactas, Universidad Nacional de La Plata y CCT-La Plata, CONICET, La Plata, Argentina
| | - J Ignacio Quelas
- Instituto de Biotecnología y Biología Molecular, Facultad de Ciencias Exactas, Universidad Nacional de La Plata y CCT-La Plata, CONICET, La Plata, Argentina
| | - Carolina Dardis
- Instituto de Biotecnología y Biología Molecular, Facultad de Ciencias Exactas, Universidad Nacional de La Plata y CCT-La Plata, CONICET, La Plata, Argentina
| | - M Julia Althabegoiti
- Instituto de Biotecnología y Biología Molecular, Facultad de Ciencias Exactas, Universidad Nacional de La Plata y CCT-La Plata, CONICET, La Plata, Argentina
| | - Aníbal R Lodeiro
- Instituto de Biotecnología y Biología Molecular, Facultad de Ciencias Exactas, Universidad Nacional de La Plata y CCT-La Plata, CONICET, La Plata, Argentina
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