Characterization of Bacterial Polysaccharide Capsules and Detection in the Presence of Deliquescent Water by Atomic Force Microscopy

Su, Hai-Nan; Chen, Zhihua; Liu, Shengbo; Qiao, Liping; Chen, Xiu-Lan; He, Hui; Zhao, Xian; Zhou, Biao; Zhang, Yuzhong

doi:10.1128/aem.00207-12

Cited by 17 publications

(13 citation statements)

References 22 publications

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“…Previous reports in literature have demonstrated the use of AFM to image and characterise the elastic and adhesive properties of bacterial cells (Dufrêne, 2014, Su et al, 2012, Wang et al, 2013, Wang et al, 2015). In this work, we have utilised a non-invasive bacteria immobilisation approach that allowed the imaging and probing of S. mitis and S. pneumoniae attached to biopolymer-coated glass substrates, in PBS.…”

Section: Discussionmentioning

confidence: 99%

“…The same group also demonstrated that the K. pneumoniae capsule altered its elasticity in response to changes in turgor pressure by absorbing counterions, so reducing the overall net charge along the capsule polysaccharide chains and protecting the bacterial cell against osmotic stress (Wang et al, 2013). Su et al , also used AFM to characterise the structure of the polysaccharide capsule of Zunongwangia profunda SM-A87 (Su et al, 2012), while Stukalov et al characterised the capsule of four different gram-negative bacterial strains by utilising both AFM and transmission electron microscopy (TEM) (Stukalov et al, 2008). While TEM allowed visualisation of the capsule for some strains, AFM was able to detect the presence of capsule on all the encapsulated strains studied (Stukalov et al, 2008).…”

Section: Introductionmentioning

confidence: 99%

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Investigating the biomechanical properties of streptococcal polysaccharide capsules using atomic force microscopy

Marshall

Aguayo

Kilian

et al. 2019

Preprint

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5In common with many bacterial pathogens, Streptococcus pneumoniae has a 3 6 polysaccharide capsule, which facilitates immune evasion and is a key virulence 3 7 determinant. However, recent data has shown that the closely related Streptococcus mitis 3 8can also express polysaccharide capsules including those with an identical chemical 3 9 structure to S. pneumoniae capsular serotypes. We have used atomic force microscopy 4 0 (AFM) techniques to investigate the biophysical properties of S. mitis and S. pneumoniae 4 1 strains expressing the same capsular serotypes that might relate to their differences in 4 2 virulence potential. When comparing S. mitis and S. pneumoniae strains with identical 4 3 capsule serotypes S. mitis strains were more susceptible to neutrophil killing and imaging 4 4using electron microscopy and AFM demonstrated significant morphological differences. 4 5Force-volume mapping using AFM showed distinct force-curve profiles for the centre and 4 6 edge areas of encapsulated S. pneumoniae and S. mitis strains. This "edge effect" was not 4 7 observed in the unencapsulated streptococcal strains and in an unencapsulated 4 8Staphylococcus aureus strain, and therefore was a direct representation of the mechanical 4 9

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Investigating the biomechanical properties of streptococcal polysaccharide capsules using atomic force microscopy

Marshall

Aguayo

Kilian

et al. 2019

Preprint

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“…Imaging was performed using a Multimode 8 AFM (Bruker) fitted with a "J" scanner, controlled by a Nanoscope V controller and using pyramidal ScanAyst-Air (Bruker) probes (with a nominal spring constant k of 0.4 N/m and tip radius of 2 nm). Scan parameters were adjusted automatically by the ScanAsyst software to optimise image quality (Su et al, 2012).…”

Section: Structural Characterisation Of Aggrecan By Afm and Multi-angmentioning

confidence: 99%

“…The compressive (reduced) modulus of hydrated tissue cryosections was assessed at the nanometre scale by AFM nanomechanical assessment on a Bruker Catalyst AFM with a Nanoscope V controller (Su et al, 2012). 20 µm-thick AC and NP cryosections were adsorbed to SuperFrost Plus slides (Thermo Scientific), air-dried for 24 h, washed with MilliQ water to remove OCT and rehydrated for 1 h prior to mechanical assessment.…”

Section: Measurement Of Nanomechanical Compressive Stiffness By Afm Imentioning

confidence: 99%

Extracellular matrix fragmentation in young, healthy cartilaginous tissues

Craddock

Hodson²,

Ozols

et al. 2018

eCM

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Although the composition and structure of cartilaginous tissues is complex, collagen II fibrils and aggrecan are the most abundant assemblies in both articular cartilage (AC) and the nucleus pulposus (NP) of the intervertebral disc (IVD). Whilst structural heterogeneity of intact aggrecan ( containing three globular domains) is well characterised, the extent of aggrecan fragmentation in healthy tissues is poorly defined. Using young, yet skeletally mature (18-30 months), bovine AC and NP tissues, it was shown that, whilst the ultrastructure of intact aggrecan was tissue-dependent, most molecules (AC: 95 %; NP: 99.5 %) were fragmented (lacking one or more globular domains). Fragments were significantly smaller and more structurally heterogeneous in the NP compared with the AC (molecular area; AC: 8543 nm 2 ; NP: 4625 nm 2 ; p < 0.0001). In contrast, fibrillar collagen appeared structurally intact and tissue-invariant. Molecular fragmentation is considered indicative of a pathology; however, these young, skeletally mature tissues were histologically and mechanically (reduced modulus: AC: ≈ 500 kPa; NP: ≈ 80 kPa) comparable to healthy tissues and devoid of notable gelatinase activity (compared with rat dermis). As aggrecan fragmentation was prevalent in neonatal bovine AC (99.5 % fragmented, molecular area: 5137 nm 2 ) as compared with mature AC (95.0 % fragmented, molecular area: 8667nm 2 ), it was hypothesised that targeted proteolysis might be an adaptive process that modified aggrecan packing (as simulated computationally) and, hence, tissue charge density, mechanical properties and porosity. These observations provided a baseline against which pathological and/or age-related fragmentation of aggrecan could be assessed and suggested that new strategies might be required to engineer constructs that mimic the mechanical properties of native cartilaginous tissues.

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“…Despite that individual EPS chains are not clearly resolved in such studies consequences of their changes are clearly emerging. The presence and overall outline of the polysaccharide capsules of the bacteria Zunongwangia profunda SM-A87 was recently characterized by tapping mode AFM ( Su et al, 2012 ). In this report, the AFM clearly revealed the overall outline of the EPS containing capsules, the fibrils, but not individual, dispersed polysaccharide.…”

Section: Scanning Probe Based Microscopy and Their Applications To MImentioning

confidence: 99%

Novel imaging technologies for characterization of microbial extracellular polysaccharides

Lilledahl

Stokke

2015

Front. Microbiol.

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Understanding of biology is underpinned by the ability to observe structures at various length scales. This is so in a historical context and is also valid today. Evolution of novel insight often emerges from technological advancement. Recent developments in imaging technologies that is relevant for characterization of extraceullar microbiological polysaccharides are summarized. Emphasis is on scanning probe and optical based techniques since these tools offers imaging capabilities under aqueous conditions more closely resembling the physiological state than other ultramicroscopy imaging techniques. Following the demonstration of the scanning probe microscopy principle, novel operation modes to increase data capture speed toward video rate, exploitation of several cantilever frequencies, and advancement of utilization of specimen mechanical properties as contrast, also including their mode of operation in liquid, have been developed on this platform. Combined with steps in advancing light microscopy with resolution beyond the far field diffraction limit, non-linear methods, and combinations of the various imaging modalities, the potential ultramicroscopy toolbox available for characterization of exopolysaccharides (EPS) are richer than ever. Examples of application of such ultramicroscopy strategies range from imaging of isolated microbial polysaccharides, structures being observed when they are involved in polyelectrolyte complexes, aspects of their enzymatic degradation, and cell surface localization of secreted polysaccharides. These, and other examples, illustrate that the advancement in imaging technologies relevant for EPS characterization supports characterization of structural aspects.

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Characterization of Bacterial Polysaccharide Capsules and Detection in the Presence of Deliquescent Water by Atomic Force Microscopy

Cited by 17 publications

References 22 publications

Investigating the biomechanical properties of streptococcal polysaccharide capsules using atomic force microscopy

Investigating the biomechanical properties of streptococcal polysaccharide capsules using atomic force microscopy

Extracellular matrix fragmentation in young, healthy cartilaginous tissues

Novel imaging technologies for characterization of microbial extracellular polysaccharides

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