Morphologic variations in bacteria under stress conditions: near-field optical studies.
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.
Cefalì
E
E
INFM and Department of Physics, University of Messina, Messina, Italy.
Patanè
S
S
Arena
A
A
Saitta
G
G
Guglielmino
S
S
Cappello
S
S
Nicolò
M
M
Allegrini
M
M
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*
D003470:Culture Media