Measuring bacterial cells size with AFM

Osiro, Denise; Filho, Rubens Bernardes; Assis, O. B. G.; Jorge, Lúcio André de Castro; Colnago, Luiz Alberto

doi:10.1590/s1517-83822012000100040

Cited by 13 publications

(9 citation statements)

References 2 publications

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“…However, it brings about an interesting question as to how Lpp is juxtaposed to other periplasmic proteins or protein complexes that perform important cellular functions. The AFM probe tip can lead to a sample broadening effect (34)(35)(36), and so, the Lpp cluster is most likely smaller than that measured. Aggregation of lipids in adjacent Lpp may also contribute to the formation of Lpp clusters.…”

Section: Discussionmentioning

confidence: 99%

In situ visualization of Braun’s lipoprotein on E. coli sacculi

et al. 2023

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Braun’s lipoprotein (Lpp) plays a major role in stabilizing the integrity of the cell envelope in Escherichia coli , as it provides a covalent cross-link between the outer membrane and the peptidoglycan layer. An important challenge in elucidating the physiological role of Lpp lies in attaining a detailed understanding of its distribution on the peptidoglycan layer. Here, using atomic force microscopy, we visualized Lpp directly on peptidoglycan sacculi. Lpp is homogeneously distributed over the outer surface of the sacculus at a high density. However, it is absent at the constriction site during cell division, revealing its role in the cell division process with Pal, another cell envelope–associated protein. Collectively, we have established a framework to elucidate the distribution of Lpp and other peptidoglycan-bound proteins via a direct imaging modality.

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Section: Discussionmentioning

confidence: 99%

In situ visualization of Braun’s lipoprotein on E. coli sacculi

et al. 2023

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“…B3), which is within the estimated 532 nm laser penetration depth (∼7.8 μm) into a bacterium based on the following equation: L = 2nλ/NA, 2 where n is the bacteria's refractive index, λ is the laser wavelength, and NA is the numerical aperture. 58,59 Thus, the incident laser can penetrate the bacteria to access the plasmonic array below for SERS. 100 spectra were measured for the blanks and each bacterial species.…”

Section: Methodsmentioning

confidence: 99%

Surface-Enhanced Raman Scattering-Based Surface Chemotaxonomy: Combining Bacteria Extracellular Matrices and Machine Learning for Rapid and Universal Species Identification

Leong,

Tan,

Han

et al. 2023

ACS Nano

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Rapid, universal, and accurate identification of bacteria in their natural states is necessary for on-site environmental monitoring and fundamental microbial research. Surface-enhanced Raman scattering (SERS) spectroscopy emerges as an attractive tool due to its molecule-specific spectral fingerprinting and multiplexing capabilities, as well as portability and speed of readout. Here, we develop a SERSbased surface chemotaxonomy that uses bacterial extracellular matrices (ECMs) as proxy biosignatures to hierarchically classify bacteria based on their shared surface biochemical characteristics to eventually identify six distinct bacterial species at >98% classification accuracy. Corroborating with in silico simulations, we establish a three-way inter-relation between the bacteria identity, their ECM surface characteristics, and their SERS spectral fingerprints. The SERS spectra effectively capture multitiered surface biochemical insights including ensemble surface characteristics, e.g., charge and biochemical profiles, and molecular-level information, e.g., types and numbers of functional groups. Our surface chemotaxonomy thus offers an orthogonal taxonomic definition to traditional classification methods and is achieved without gene amplification, biochemical testing, or specific biomarker recognition, which holds great promise for point-of-need applications and microbial research.

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“…For the images/observations taken in air, the deposition of bacteria on the mica surfaces was carried out as described before 85,86 and used for other Gram-negative bacteria 45,48,87 , with few modifications. In brief and during the optimization of the protocol, PBS and deionized water were tested to prepare the bacterial suspension aliquots prior to deposition on mica.…”

Section: Methodsmentioning

confidence: 99%

Variation of Burkholderia cenocepacia cell wall morphology and mechanical properties during cystic fibrosis lung infection, assessed by atomic force microscopy

Hassan

Vitorino

Robalo

et al. 2019

Sci Rep

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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.

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Measuring bacterial cells size with AFM

Cited by 13 publications

References 2 publications

In situ visualization of Braun’s lipoprotein on E. coli sacculi

In situ visualization of Braun’s lipoprotein on E. coli sacculi

Surface-Enhanced Raman Scattering-Based Surface Chemotaxonomy: Combining Bacteria Extracellular Matrices and Machine Learning for Rapid and Universal Species Identification

Variation of Burkholderia cenocepacia cell wall morphology and mechanical properties during cystic fibrosis lung infection, assessed by atomic force microscopy

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