Motion of a Cell Wall Polysaccharide Observed by Atomic Force Microscopy

2000 ◽  
Vol 33 (15) ◽  
pp. 5680-5685 ◽  
Author(s):  
A. Patrick Gunning ◽  
Alan R. Mackie ◽  
Andrew R. Kirby ◽  
Paul Kroon ◽  
Gary Williamson ◽  
...  
2018 ◽  
pp. 335-347 ◽  
Author(s):  
Thomas Torode ◽  
Marina Linardic ◽  
J. Louis Kaplan ◽  
Siobhan A. Braybrook

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
A. Amir Hassan ◽  
Miguel V. Vitorino ◽  
Tiago Robalo ◽  
Mário S. Rodrigues ◽  
Isabel Sá-Correia

Abstract The influence that Burkholderia cenocepacia adaptive evolution during long-term infection in cystic fibrosis (CF) patients has on cell wall morphology and mechanical properties is poorly understood despite their crucial role in cell physiology, persistent infection and pathogenesis. Cell wall morphology and physical properties of three B. cenocepacia isolates collected from a CF patient over a period of 3.5 years were compared using atomic force microscopy (AFM). These serial clonal variants include the first isolate retrieved from the patient and two late isolates obtained after three years of infection and before the patient’s death with cepacia syndrome. A consistent and progressive decrease of cell height and a cell shape evolution during infection, from the typical rods to morphology closer to cocci, were observed. The images of cells grown in biofilms showed an identical cell size reduction pattern. Additionally, the apparent elasticity modulus significantly decreases from the early isolate to the last clonal variant retrieved from the patient but the intermediary highly antibiotic resistant clonal isolate showed the highest elasticity values. Concerning the adhesion of bacteria surface to the AFM tip, the first isolate was found to adhere better than the late isolates whose lipopolysaccharide (LPS) structure loss the O-antigen (OAg) during CF infection. The OAg is known to influence Gram-negative bacteria adhesion and be an important factor in B. cenocepacia adaptation to chronic infection. Results reinforce the concept of the occurrence of phenotypic heterogeneity and adaptive evolution, also at the level of cell size, form, envelope topography and physical properties during long-term infection.


Microscopy ◽  
2020 ◽  
Vol 69 (6) ◽  
pp. 350-359
Author(s):  
Nobuhiro Morone ◽  
Eiji Usukura ◽  
Akihiro Narita ◽  
Jiro Usukura

Abstract Unroofing, which is the mechanical shearing of a cell to expose the cytoplasmic surface of the cell membrane, is a unique preparation method that allows membrane cytoskeletons to be observed by cryo-electron microscopy, atomic force microscopy, freeze-etching electron microscopy and other methods. Ultrasound and adhesion have been known to mechanically unroof cells. In this study, unroofing using these two means was denoted sonication unroofing and adhesion unroofing, respectively. We clarified the mechanisms by which cell membranes are removed in these unroofing procedures and established efficient protocols for each based on the mechanisms. In sonication unroofing, fine bubbles generated by sonication adhered electrostatically to apical cell surfaces and then removed the apical (dorsal) cell membrane with the assistance of buoyancy and water flow. The cytoplasmic surface of the ventral cell membrane remaining on the grids became observable by this method. In adhesion unroofing, grids charged positively by coating with Alcian blue were pressed onto the cells, thereby tightly adsorbing the dorsal cell membrane. Subsequently, a part of the cell membrane strongly adhered to the grids was peeled from the cells and transferred onto the grids when the grids were lifted. This method thus allowed the visualization of the cytoplasmic surface of the dorsal cell membrane. This paper describes robust, improved protocols for the two unroofing methods in detail. In addition, micro-unroofing (perforation) likely due to nanobubbles is introduced as a new method to make cells transparent to electron beams.


Yeast ◽  
2010 ◽  
Vol 27 (8) ◽  
pp. 673-684 ◽  
Author(s):  
Etienne Dague ◽  
Rajaa Bitar ◽  
Hubert Ranchon ◽  
Fabien Durand ◽  
Hélène Martin Yken ◽  
...  

Botany ◽  
2008 ◽  
Vol 86 (4) ◽  
pp. 385-397 ◽  
Author(s):  
Haley D.M. Wyatt ◽  
Neil W. Ashton ◽  
Tanya E.S. Dahms

The moss Physcomitrella patens (Hedw.) Bruch & Schimp. in B.S.G. serves as a nonvascular plant model system suitable for studying many plant developmental phenomena. The tip-growing filamentous protonemal stage of its life cycle exhibits polarized growth and various tropic responses. Conventional staining and light microscopy (LM) were used to provide the first direct evidence that protonemal cells of P. patens lack a cuticle. Atomic force microscopy (ATM) images reveal detailed surface structures identified by scanning electron microscopy (SEM). The cell wall ultrastructure is characterized by rounded protrusions that are uniformly distributed along each caulonemal filament, and longer fibrillar structures, which are disorganized at the apex, but become oriented in longitudinal arrays parallel to the growth axis in more proximal regions of caulonemal apical cells. The subapical cells are characterized by a polylamellated texture. There was no difference in gross surface ultrastructure between light-grown and dark-grown filaments, but the dimensions of the rounded protrusions at the apices of caulonemata cultured in the light and in darkness were significantly different. The convex and concave cell wall surfaces of a curved, gravitropically responding dark-grown caulonema appear structurally different. This investigation is the first to use AFM to probe the cell wall ultrastructure of a bryophyte. The data further elaborate a simple model of cell wall development in the caulonemata of P. patens that was proposed for other tip-growing filamentous plants.


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