Microbial nanoscopy: a closer look at microbial cell surfaces.

Institute of Condensed Matter and Nanosciences, Université Catholique de Louvain, Croix du Sud 2/18, B-1348 Louvain-la-Neuve, Belgium.
Trends in Microbiology (Impact Factor: 8.43). 09/2010; 18(9):397-405. DOI: 10.1016/j.tim.2010.06.004
Source: PubMed

ABSTRACT How cell envelope constituents are spatially organised and how they interact with the environment are key questions in microbiology. Unlike other bioimaging tools, atomic force microscopy (AFM) provides information about the nanoscale surface architecture of living cells and about the localization and interactions of their individual constituents. These past years have witnessed remarkable advances in our use of the AFM molecular toolbox to observe and force probe microbial cells. Recent milestones include the real-time imaging of the nanoscale organization of cell walls, the quantification of subcellular chemical heterogeneities, the mapping and functional analysis of individual cell wall constituents and the analysis of the mechanical properties of single receptors and sensors.

  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Peptidoglycan performs the essential role of resisting turgor in the cell walls of most bacteria. It determines cell shape, and its biosynthesis is the target for many important antibiotics. The fundamental chemical building blocks of peptidoglycan are conserved: repeating disaccharides cross linked by peptides. However, these blocks come in many varieties and can be assembled in different ways. So beyond the fundamental similarity, prodigious chemical, organizational and architectural diversity is revealed. Here, we track the evolution of our current understanding of peptidoglycan and underpinning technical and methodological developments. The origin and function of chemical diversity is discussed with respect to some well-studied example species. We then explore how this chemistry is manifested in elegant and complex peptidoglycan organization and how this is interpreted in different and sometimes controversial architectural models. We contend that emerging technology brings about the possibility of achieving a complete understanding of peptidoglycan chemistry, through architecture, to the way in which diverse species and populations of cells meet the challenges of maintaining viability and growth within their environmental niches by exploiting the bioengineering versatility of peptidoglycan.
    Molecular Microbiology 01/2014; · 5.03 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Originally invented for topographic imaging, atomic force microscopy (AFM) has evolved into a multifunctional biological toolkit, enabling to measure structural and functional details of cells and molecules. Its versatility and the large scope of information it can yield make it an invaluable tool in any biologically oriented laboratory, where researchers need to perform characterizations of living samples as well as single molecules in quasi-physiological conditions and with nanoscale resolution. In the last 20 years, AFM has revolutionized the characterization of microbial cells by allowing a better understanding of their cell wall and of the mechanism of action of drugs and by becoming itself a powerful diagnostic tool to study bacteria. Indeed, AFM is much more than a high-resolution microscopy technique. It can reconstruct force maps that can be used to explore the nanomechanical properties of microorganisms and probe at the same time the morphological and mechanical modifications induced by external stimuli. Furthermore it can be used to map chemical species or specific receptors with nanometric resolution directly on the membranes of living organisms. In summary, AFM offers new capabilities and a more in-depth insight in the structure and mechanics of biological specimens with an unrivaled spatial and force resolution. Its application to the study of bacteria is extremely significant since it has already delivered important information on the metabolism of these small microorganisms and, through new and exciting technical developments, will shed more light on the real-time interaction of antimicrobial agents and bacteria. For further resources related to this article, please visit the WIREs website. Conflict of interest: The authors have declared no conflicts of interest for this article.
    Wiley Interdisciplinary Reviews Nanomedicine and Nanobiotechnology 02/2014; · 5.68 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Dairy products are important sources of biological active compounds that can be interesting for human health. This includes immunoglobulins, whey proteins and peptides, polar lipids, lactic acid bacteria and in particular, probiotics which include many types of lactic acid bacteria. Understanding the interactions between these bioactive components and their delivery matrix may improve the success of their transport to their target site of action. Pioneering research on probiotic lactic acid bacteria has mainly focused on their host effects. However, little was done about their interaction with dairy ingredients. Such knowledge could contribute to design of new and more efficient dairy food, and to understand the interplay between the various constituents. The purpose of this review is first to provide an overview of current knowledge about biomolecules encountered on bacterial surface and dairy components composition. In order to understand how bacteria can interact with dairy molecules, adhesion mechanisms are discussed with regards to the environmental conditions affecting the bacterial adhesion. Methods that can be used to investigate the bacterial surface and the ones that can probe bacterial interactions with other components are also detailed. Finally, the interest in studying bacterial interactions with milk components is illustrated by relevant industrial examples, as the influence of bacterial surface biomolecules on yogurt structure or the bacterial location in a dairy matrix.
    Advances in Colloid and Interface Science 12/2014; · 8.64 Impact Factor

Full-text (2 Sources)

Available from
May 22, 2014