title: Morphologic variations in bacteria under stress conditions: near-field optical studies.
abstract: The morphologic and structural variations suffered by cells of a population of Pseudomonas aeruginosa ATCC 27853 under stress conditions were investigated by using scanning near-field optical microscopy. The analysis of the images, supported by microbiological data, showed that the bacteria evolved from the initial distribution of rod-shaped cells of standard size to a population with structural and morphologic modifications. The detection of variations in the optical reflectivity over a subwavelength scale (< or = 100 nm), combined with the concurrently acquired topographical signal, allowed the visualisation of rod-shaped bacteria going towards a lytic process and entire "U"-shaped cells. In the latter cells, which derived from a morphology refolding of rod bacteria, cellular matter seemed to rearrange itself to attain a coccoid stress resistant form, responsible for the residual viability of the population.
authors.affiliation: INFM and Department of Physics, University of Messina, Messina, Italy.
authors.forename: E
authors.initials: E
authors.lastname: Cefalì
authors.forename: S
authors.initials: S
authors.lastname: Patanè
authors.forename: A
authors.initials: A
authors.lastname: Arena
authors.forename: G
authors.initials: G
authors.lastname: Saitta
authors.forename: S
authors.initials: S
authors.lastname: Guglielmino
authors.forename: S
authors.initials: S
authors.lastname: Cappello
authors.forename: M
authors.initials: M
authors.lastname: Nicolò
authors.forename: M
authors.initials: M
authors.lastname: Allegrini
mesh_terms: D018533:Biomass; D015169:Colony Count, Microbial; D003470:Culture Media; D008855:Microscopy, Electron, Scanning / Q000379:methods; D008858:Microscopy, Phase-Contrast; D011550:Pseudomonas aeruginosa / Q000254:growth & development / Q000502:physiology* / Q000648:ultrastructure*
chemical_list: D003470:Culture Media