出版者・発行元：Cold Spring Harbor Laboratory  

Abstract

The FtsZ protein is involved in bacterial cell division. In cell-walled bacteria, such asBacillus subtilis, FtsZ forms a ring-like structure, called the Z ring, at the cell division site and acts as a scaffold for cell wall synthesis. The inhibition of cell wall synthesis inB. subtilishas been shown to interfere with the function of the Z ring, causing a loss in cell division control.Spiroplasma, a cell wall-less bacterium, lacks most of the genes involved in cell division; however, theftsZgene remains conserved. The function ofSpiroplasma eriocheirisFtsZ (SeFtsZ) remains to be determined. In the present study, we analyzed the biochemical characteristics of SeFtsZ. Purified SeFtsZ demonstrated lower polymerization capacity and GTPase activity than FtsZ fromE. coliandB. subtilis. We also investigated the relationship between SeFtsZ and SeSepF, which anchors FtsZ to the cell membrane, and found that SeSepF did not contribute to the stability of FtsZ filaments, unlike theB. subtilisSepF. SeFtsZ and SeSepF were produced inE. coliL-forms, where cell wall synthesis was inhibited. SeFtsZ formed ring-like structures in cell wall-lessE. colicells, suggesting that SeFtsZ forms Z rings and is involved in cell division independently of cell wall synthesis.

DOI： 10.1101/2024.10.15.618391

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

Peptidoglycan for elongation in Escherichia coli is synthesized by the Rod complex, which includes RodZ. Although various mutant strains of the Rod complex have been isolated, the relationship between the activity of the Rod complex and the overall physical and chemical structures of the peptidoglycan have not been reported. We constructed a RodZ mutant, termed RMR, and analyzed the growth rate, morphology, and other characteristics of cells producing the Rod complexes containing RMR. The growth and morphology of RMR cells were abnormal, and we isolated suppressor mutants from RMR cells. Most of the suppressor mutations were found in components of the Rod complex, suggesting that these suppressor mutations increase the integrity and/or the activity of the Rod complex. We purified peptidoglycan from wild-type, RMR, and suppressor mutant cells and observed their structures in detail. We found that the peptidoglycan purified from RMR cells had many large holes and different compositions of muropeptides from those of WT cells. The Rod complex may be a determinant not only for the whole shape of peptidoglycan but also for its highly dense structure to support the mechanical strength of the cell wall.

DOI： 10.1002/mbo3.1385

PubMed

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

Mycoplasma mobile forms a membrane protrusion at a pole as an organelle. M. mobile cells bind to solid surfaces and glide in the direction of the protrusion. In gliding motility, M. mobile cells catch, pull and release sialylated oligosaccharides on host cells. The observation of Mycoplasma species under light microscopy is useful for the analysis of adhesion ability and the motility mechanism.

DOI： 10.1007/978-1-0716-3060-0_26

PubMed

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

Mycoplasma mobile, a parasitic bacterium, glides on solid surfaces, such as animal cells and glass, by a special mechanism. This process is driven by the force generated through ATP hydrolysis on an internal structure. However, the spatial and temporal behaviors of the internal structures in living cells are unclear. In this study, we detected the movements of the internal structure by scanning cells immobilized on a glass substrate using high-speed atomic force microscopy (HS-AFM). By scanning the surface of a cell, we succeeded in visualizing particles, 2 nm in height and aligned mostly along the cell axis with a pitch of 31.5 nm, consistent with previously reported features based on electron microscopy. Movements of individual particles were then analyzed by HS-AFM. In the presence of sodium azide, the average speed of particle movements was reduced, suggesting that movement is linked to ATP hydrolysis. Partial inhibition of the reaction by sodium azide enabled us to analyze particle behavior in detail, showing that the particles move 9 nm right, relative to the gliding direction, and 2 nm into the cell interior in 330 ms and then return to their original position, based on ATP hydrolysis. IMPORTANCE The Mycoplasma genus contains bacteria generally parasitic to animals and plants. Some Mycoplasma species form a protrusion at a pole, bind to solid surfaces, and glide by a special mechanism linked to their infection and survival. The special machinery for gliding can be divided into surface and internal structures that have evolved from rotary motors represented by ATP synthases. This study succeeded in visualizing the real-time movements of the internal structure by scanning from the outside of the cell using an innovative high-speed atomic force microscope and then analyzing their behaviors.

DOI： 10.1128/mBio.00040-21

PubMed

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

Gram-negative bacteria such as Escherichia coli are surrounded by an outer membrane, which encloses a peptidoglycan layer. Even if thinner than in many Gram-positive bacteria, the peptidoglycan in E. coli allows cells to withstand turgor pressure in hypotonic medium. In hypertonic medium, E. coli treated with a cell wall synthesis inhibitor such as penicillin G form wall-deficient cells. These so-called L-form cells grow well under anaerobic conditions (i.e., in the absence of oxidative stress), becoming deformed and dividing as L-form. Upon removal of the inhibitor, they return to the walled rod-shaped state. Recently, the outer membrane was reported to provide rigidity to Gram-negative bacteria and to strengthen wall-deficient cells. However, it remains unclear why L-form cells need the outer membrane for growth. Using a microfluidic system, we found that, upon treatment with the outer membrane-disrupting drugs polymyxin B and polymyxin B nonapeptide or with the outer membrane synthesis inhibitor CHIR-090, the cells lysed during cell deformation and division, indicating that the outer membrane was important even in hypertonic medium. L-form cells could return to rod-shaped when trapped in a narrow space, but not in a wide space, likely due to insufficient physical force. Outer membrane rigidity could be compromised by lack of outer membrane proteins; Lpp, OmpA, or Pal. Deletion of lpp caused cells to lyse during cell deformation and cell division. In contrast, ompA and pal mutants could be deformed and return to small oval cells even when less physical force was exerted. These results strongly suggest that wall-deficient E. coli cells require a rigid outer membrane to survive, but not too rigid to prevent them from changing cell shape.

DOI： 10.3389/fmicb.2021.645965

PubMed

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記述言語：日本語   出版者・発行元：公益社団法人 日本顕微鏡学会  

<i>Mycoplasma mobile</i>（以下モービレ）は，ペプチドグリカン層を持たない，魚の病原細菌（単細胞の生物）である．モービレは固形物表面にはりつき，はりついたまま滑るように動く滑走運動を行う．滑走メカニズムにおいて，モービレの細胞表面にあるタンパク質でできた“あし”が，宿主細胞表面のシアル酸オリゴ糖を引き寄せ，菌体を前に進める．この滑走運動は，細胞内部にあるモーターがATPを加水分解することにより駆動されるが，ATPの加水分解によりモーターがどのような構造変化を起こすかは明らかになっていない．そこで本研究では，高速原子間力顕微鏡（以下高速AFM）を用いて，細胞内部におけるモーターの動きを可視化することを目的とした．ガラス基板表面に貼り付けた細胞表面を高速AFMでスキャンすると，内部モーターと思われる粒状の構造がシート状に並んでいる様子が見られた．さらに，個々の粒子は滑走方向に対して右方向に8.2 nmシフトする動きを示した．

DOI： 10.11410/kenbikyo.54.2_67

CiNii Article

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その他リンク： https://ndlsearch.ndl.go.jp/books/R000000004-I030011194

記述言語：日本語   出版者・発行元：吹田 : 日本生物工学会  

コレクション : 国立国会図書館デジタルコレクション > 電子書籍・電子雑誌 > 学術機関 > 学協会

CiNii Article

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その他リンク： https://ndlsearch.ndl.go.jp/books/R000000004-I029033505

開催年月日： 2023年7月16日 - 2023年7月20日

記述言語：英語   会議種別：ポスター発表  

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開催年月日： 2017年7月16日 - 2017年7月20日

記述言語：英語   会議種別：ポスター発表  

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開催年月日： 2015年5月22日 - 2015年5月23日

会議種別：口頭発表（一般）  

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開催年月日： 2014年5月22日 - 2014年5月23日

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開催年月日： 2013年5月23日 - 2013年5月24日

会議種別：口頭発表（一般）  

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