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Article ; Online: Motility of the Zoonotic Spirochete

Nakamura, Shuichi

International journal of molecular sciences

2022 Volume 23, Issue 3

Abstract: If a bacterium has motility, it will use the ability to survive and thrive. For many pathogenic species, their motilities are a crucial virulence factor. The form of motility varies among the species. Some use flagella for swimming in liquid, and others ... ...

Abstract	If a bacterium has motility, it will use the ability to survive and thrive. For many pathogenic species, their motilities are a crucial virulence factor. The form of motility varies among the species. Some use flagella for swimming in liquid, and others use the cell-surface machinery to move over solid surfaces. Spirochetes are distinguished from other bacterial species by their helical or flat wave morphology and periplasmic flagella (PFs). It is believed that the rotation of PFs beneath the outer membrane causes transformation or rolling of the cell body, propelling the spirochetes. Interestingly, some spirochetal species exhibit motility both in liquid and over surfaces, but it is not fully unveiled how the spirochete pathogenicity involves such amphibious motility. This review focuses on the causative agent of zoonosis leptospirosis and discusses the significance of their motility in liquid and on surfaces, called crawling, as a virulence factor.
MeSH term(s)	Animals ; Bacterial Zoonoses/microbiology ; Flagella/physiology ; Humans ; Leptospira/pathogenicity ; Leptospira/physiology ; Leptospirosis/microbiology ; Surface Properties ; Virulence Factors/physiology
Chemical Substances	Virulence Factors
Language	English
Publishing date	2022-02-07
Publishing country	Switzerland
Document type	Journal Article ; Review
ZDB-ID	2019364-6
ISSN	1422-0067 ; 1422-0067 ; 1661-6596
ISSN (online)	1422-0067
ISSN	1422-0067 ; 1661-6596
DOI	10.3390/ijms23031859
Database	MEDical Literature Analysis and Retrieval System OnLINE

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Article ; Online: Spirochete Flagella and Motility.

Nakamura, Shuichi

Biomolecules

2020 Volume 10, Issue 4

Abstract: Spirochetes can be distinguished from other flagellated bacteria by their long, thin, spiral (or wavy) cell bodies and endoflagella that reside within the periplasmic space, designated as periplasmic flagella (PFs). Some members of the spirochetes are ... ...

Abstract	Spirochetes can be distinguished from other flagellated bacteria by their long, thin, spiral (or wavy) cell bodies and endoflagella that reside within the periplasmic space, designated as periplasmic flagella (PFs). Some members of the spirochetes are pathogenic, including the causative agents of syphilis, Lyme disease, swine dysentery, and leptospirosis. Furthermore, their unique morphologies have attracted attention of structural biologists; however, the underlying physics of viscoelasticity-dependent spirochetal motility is a longstanding mystery. Elucidating the molecular basis of spirochetal invasion and interaction with hosts, resulting in the appearance of symptoms or the generation of asymptomatic reservoirs, will lead to a deeper understanding of host-pathogen relationships and the development of antimicrobials. Moreover, the mechanism of propulsion in fluids or on surfaces by the rotation of PFs within the narrow periplasmic space could be a designing base for an autonomously driving micro-robot with high efficiency. This review describes diverse morphology and motility observed among the spirochetes and further summarizes the current knowledge on their mechanisms and relations to pathogenicity, mainly from the standpoint of experimental biophysics.
MeSH term(s)	Flagella/metabolism ; Movement ; Periplasm/metabolism ; Spirochaetales/cytology ; Spirochaetales/physiology
Language	English
Publishing date	2020-04-04
Publishing country	Switzerland
Document type	Journal Article ; Research Support, Non-U.S. Gov't ; Review
ZDB-ID	2701262-1
ISSN	2218-273X ; 2218-273X
ISSN (online)	2218-273X
ISSN	2218-273X
DOI	10.3390/biom10040550
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Article ; Online: Measurement of the Cell-Body Rotation of Leptospira.

Nakamura, Shuichi

Methods in molecular biology (Clifton, N.J.)

2020 Volume 2134, Page(s) 139–148

Abstract: Leptospira spp. swim in liquid and crawl on surfaces with two periplasmic flagella. The periplasmic flagella attach to the protoplasmic cylinder via basal rotary motors (flagellar motors) and transform the ends of the cell body into spiral or hook shape. ...

Abstract	Leptospira spp. swim in liquid and crawl on surfaces with two periplasmic flagella. The periplasmic flagella attach to the protoplasmic cylinder via basal rotary motors (flagellar motors) and transform the ends of the cell body into spiral or hook shape. The rotations of the periplasmic flagella are thought to gyrate the cell body and rotate the protoplasmic cylinder for propelling the cell; however, the motility mechanism has not been fully elucidated. Since the motility is a critical virulence factor for pathogenic leptospires, the kinematic insight is valuable to understand the mechanism of infection. This chapter describes microscopic methodologies to measure the motility of Leptospira, focusing on rotation of the helical cell body.
MeSH term(s)	Cell Body/metabolism ; Cell Body/ultrastructure ; Cell Movement/physiology ; Flagella/metabolism ; Flagella/ultrastructure ; Leptospira/metabolism ; Leptospira/ultrastructure ; Microscopy/methods ; Periplasm/metabolism ; Periplasm/physiology ; Virulence Factors/metabolism
Chemical Substances	Virulence Factors
Language	English
Publishing date	2020-06-03
Publishing country	United States
Document type	Journal Article
ISSN	1940-6029
ISSN (online)	1940-6029
DOI	10.1007/978-1-0716-0459-5_13
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Article ; Online: Accessing unnatural α-amino acids with tetrasubstituted stereogenic centers

Yasukawa, Naoki / Nakamura, Shuichi

Chemical communications (Cambridge, England)

2023 Volume 59, Issue 54, Page(s) 8343–8374

Abstract: Catalytic enantioselective synthesis methodologies have been actively explored and developed owing to the significance of chiral molecules and their utilities. In particular, unnatural α-amino acids with tetrasubstituted stereogenic carbon centers (α- ... ...

Abstract	Catalytic enantioselective synthesis methodologies have been actively explored and developed owing to the significance of chiral molecules and their utilities. In particular, unnatural α-amino acids with tetrasubstituted stereogenic carbon centers (α-tertiary amino acids; ATAAs) are undoubtedly among the most valuable compounds. Asymmetric addition to an α-iminoester or α-iminoamide is widely recognized as a straightforward, powerful, and atom-economical strategy for accessing optically active α-amino acids and their derivatives. However, this type of chemistry, which relies on ketimine-type electrophiles, was quite limited only a few decades ago owing to low reactivities and difficulties associated with enantiofacial control. This feature article comprehensively overviews this research field and highlights the significant progress that has been made. In particular, it focuses on the chiral catalyst system and the transition state as the key parameters for such reactions.
Language	English
Publishing date	2023-07-04
Publishing country	England
Document type	Journal Article ; Review
ZDB-ID	1472881-3
ISSN	1364-548X ; 1359-7345 ; 0009-241X
ISSN (online)	1364-548X
ISSN	1359-7345 ; 0009-241X
DOI	10.1039/d3cc02236f
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Article ; Online: High-Resolution Rotation Assay of the Bacterial Flagellar Motor Near Zero Loads Using a Mutant Having a Rod-Like Straight Hook.

Nakamura, Shuichi / Minamino, Tohru

Methods in molecular biology (Clifton, N.J.)

2023 Volume 2646, Page(s) 125–131

Abstract: The bacterial flagellar motor is embedded within the cell envelop and rotates the long helical filament, which acts as a molecular screw to propel the bacterium. The flagellar motor comprises a rotor and a dozen stator units, converting ion flux through ... ...

Abstract	The bacterial flagellar motor is embedded within the cell envelop and rotates the long helical filament, which acts as a molecular screw to propel the bacterium. The flagellar motor comprises a rotor and a dozen stator units, converting ion flux through the stator unit into torque. However, the energy coupling mechanism has not been fully understood. Various methods for rotation measurement have been developed to understand the rotation mechanism of the flagellar motor, but the most preferred method in recent studies is a bead assay, which tracks the rotation of a micron to submicron bead attached to the partially sheared flagellar filament at high temporal and spatial resolutions. The bead assay allows us to assess the motor rotation over a wide range of external load, but the elasticity of the axial parts of the flagellum, such as the hook and filament, limits the spatiotemporal resolution. In this chapter, we describe a bead assay optimized for the analysis of the flagellar motor dynamics at near zero load.
MeSH term(s)	Rotation ; Molecular Motor Proteins/genetics ; Bacteria ; Flagella ; Biological Assay ; Bacterial Proteins/genetics
Chemical Substances	Molecular Motor Proteins ; Bacterial Proteins
Language	English
Publishing date	2023-02-24
Publishing country	United States
Document type	Journal Article ; Research Support, Non-U.S. Gov't
ISSN	1940-6029
ISSN (online)	1940-6029
DOI	10.1007/978-1-0716-3060-0_11
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Article ; Online: [Mechanism of bacterial motility].

Nakamura, Shuichi

Nihon saikingaku zasshi. Japanese journal of bacteriology

2019 Volume 74, Issue 2, Page(s) 157–165

Abstract: Bacteria, life living at microscale, can spread only by thermal fluctuation. However, the ability of directional movement, such as swimming by rotating flagella, gliding over surfaces via mobile cell-surface adhesins, and actin-dependent movement, could ... ...

Abstract	Bacteria, life living at microscale, can spread only by thermal fluctuation. However, the ability of directional movement, such as swimming by rotating flagella, gliding over surfaces via mobile cell-surface adhesins, and actin-dependent movement, could be useful for thriving through searching more favorable environments, and such motility is known to be related to pathogenicity. Among diverse migration mechanisms, perhaps flagella-dependent motility would be used by most species. The bacterial flagellum is a molecular nanomachine comprising a helical filament and a basal motor, which is fueled by an electrochemical gradient of cation across the cell membrane (ion motive force). Many species, such as Escherichia coli, possess flagella on the outside of the cell body, whereas flagella of spirochetes reside within the periplasmic space. Flagellar filaments or helical spirochete bodies rotate like a screw propeller, generating propulsive force. This review article describes the current knowledge of the structure and operation mechanism of the bacterial flagellum, and flagella-dependent motility in highly viscous environments.
MeSH term(s)	Bacteria/cytology ; Bacteria/genetics ; Bacteria/metabolism ; Bacteria/pathogenicity ; Bacterial Physiological Phenomena ; Cell Membrane/metabolism ; Cell Movement/physiology ; Flagella/physiology ; Movement/physiology
Language	Japanese
Publishing date	2019-07-16
Publishing country	Japan
Document type	Journal Article ; Review
ZDB-ID	604101-2
ISSN	1882-4110 ; 0021-4930
ISSN (online)	1882-4110
ISSN	0021-4930
DOI	10.3412/jsb.74.157
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Article ; Online: Enantioselective Reaction of 2H-Azirines.

Nakamura, Shuichi

Chemistry, an Asian journal

2019 Volume 14, Issue 9, Page(s) 1323–1330

Abstract: 2H-Azirines are useful precursors for the synthesis of a variety of chiral aziridine and amine derivatives with a range of biological activities. Owing to the ring strain and the presence of a C=N double bond, 2H-azirines are more reactive than other ... ...

Abstract	2H-Azirines are useful precursors for the synthesis of a variety of chiral aziridine and amine derivatives with a range of biological activities. Owing to the ring strain and the presence of a C=N double bond, 2H-azirines are more reactive than other types of ketimine, and undergo a range of enantioselective reactions, including reduction and Diels-Alder reactions, as well as nucleophilic addition to the C=N double bond. Therefore, the enantioselective reactions of 2H-azirines has become a hot topic, in particular within the last few years. In this Minireview, we focus on the enantioselective reactions of 2H-azirines by using catalytic or stoichiometric amounts of chiral additives, the reaction mechanisms, and the applications of these reactions of 2H-azirines and related compounds in organic synthesis.
Language	English
Publishing date	2019-03-28
Publishing country	Germany
Document type	Journal Article ; Review
ISSN	1861-471X
ISSN (online)	1861-471X
DOI	10.1002/asia.201900107
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Article ; Online: Machine learning-based motion tracking reveals an inverse correlation between adhesivity and surface motility of the leptospirosis spirochete.

Abe, Keigo / Koizumi, Nobuo / Nakamura, Shuichi

Nature communications

2023 Volume 14, Issue 1, Page(s) 7703

Abstract: Bacterial motility is often a crucial virulence factor for pathogenic species. A common approach to study bacterial motility is fluorescent labeling, which allows detection of individual bacterial cells in a population or in host tissues. However, the ... ...

Abstract	Bacterial motility is often a crucial virulence factor for pathogenic species. A common approach to study bacterial motility is fluorescent labeling, which allows detection of individual bacterial cells in a population or in host tissues. However, the use of fluorescent labeling can be hampered by protein expression stability and/or interference with bacterial physiology. Here, we apply machine learning to microscopic image analysis for label-free motion tracking of the zoonotic bacterium Leptospira interrogans on cultured animal cells. We use various leptospiral strains isolated from a human patient or animals, as well as mutant strains. Strains associated with severe disease, and mutant strains lacking outer membrane proteins (OMPs), tend to display fast mobility and reduced adherence on cultured kidney cells. Our method does not require fluorescent labeling or genetic manipulation, and thus could be applied to study motility of many other bacterial species.
MeSH term(s)	Animals ; Humans ; Spirochaetales ; Leptospirosis/genetics ; Leptospirosis/microbiology ; Leptospirosis/pathology ; Leptospira interrogans/genetics ; Leptospira ; Membrane Proteins/metabolism ; Spirochaeta
Chemical Substances	Membrane Proteins
Language	English
Publishing date	2023-12-05
Publishing country	England
Document type	Journal Article
ZDB-ID	2553671-0
ISSN	2041-1723 ; 2041-1723
ISSN (online)	2041-1723
ISSN	2041-1723
DOI	10.1038/s41467-023-43366-0
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Article ; Online: Direct Catalytic Enantioselective Reaction of α-Isocyanoacetonitriles with Ketimines Using Cinchona Alkaloid Amide-Cu(II) Catalysts.

Nakamura, Shuichi / Kibe, Masato / Takehara, Tsunayoshi / Suzuki, Takeyuki

Organic letters

2023 Volume 25, Issue 6, Page(s) 1040–1044

Abstract: The first enantioselective reaction of α-isocyanoacetonitriles was developed. The reaction of various α-isocyanoacetonitriles with ketimines using cinchona alkaloid amide-Cu(II) catalysts afforded imidazolines with consecutive tetrasubstituted ... ...

Abstract	The first enantioselective reaction of α-isocyanoacetonitriles was developed. The reaction of various α-isocyanoacetonitriles with ketimines using cinchona alkaloid amide-Cu(II) catalysts afforded imidazolines with consecutive tetrasubstituted stereogenic carbon centers in good yields and high diastereo- and enantioselectivities. The stereoselectivity of the reaction is explained on the basis of the control experiment and density functional theory (DFT) calculations. The products were subsequently converted into chiral compounds. This process highlights the possible use of α-isocyanoacetonitriles for asymmetric and organic syntheses.
Language	English
Publishing date	2023-02-07
Publishing country	United States
Document type	Journal Article
ISSN	1523-7052
ISSN (online)	1523-7052
DOI	10.1021/acs.orglett.3c00259
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Article ; Online: Force Measurement of Bacterial Swimming Using Optical Tweezers.

Abe, Keigo / Takabe, Kyosuke / Nakamura, Shuichi

Methods in molecular biology (Clifton, N.J.)

2023 Volume 2646, Page(s) 169–179

Abstract: Velocity is a physical parameter most commonly used to quantify bacterial swimming. In the steady-state motion at a low Reynolds number, the swimming force can be estimated from the swimming velocity and the drag coefficient based on the assumption that ... ...

Abstract	Velocity is a physical parameter most commonly used to quantify bacterial swimming. In the steady-state motion at a low Reynolds number, the swimming force can be estimated from the swimming velocity and the drag coefficient based on the assumption that the swimming force balances with the drag force exerted on the bacterium. Though the velocity-force relation provides a significant clue to understand the swimming mechanism, the odd configuration of bacteria could develop problems with the accuracy of the force estimation. This chapter describes the force measurement using optical tweezers. The method uses parameters obtained from the shape and movement of a microsphere attached to the bacteria, improving the quantitativeness of force measurement.
MeSH term(s)	Swimming ; Optical Tweezers ; Biomechanical Phenomena ; Mechanical Phenomena ; Bacteria
Language	English
Publishing date	2023-02-24
Publishing country	United States
Document type	Journal Article ; Research Support, Non-U.S. Gov't
ISSN	1940-6029
ISSN (online)	1940-6029
DOI	10.1007/978-1-0716-3060-0_15
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