Electron microscopic studies of aggregation and pellicle formation inAzospirillum spp.
- 52 Downloads
Microscopic studies on aggregation ofAzospirillum brasilense Cd and the local isolate Cd-1 revealed the presence of an extracellular layer (ECL) on the outer surface of cells taken from the early exponential phase. Incubation of the bacteria with cationized ferritin (CF) was followed by labelling of the ECL of both Cd and Cd-1 taken from the stationary phase. Concanavalin-A-ferritin (Con-A-F), a lectin conjugated with ferritin, was bound to the ECL which was developed during the stationary phase, but not the exponential phase, in both isolates. In static liquid cultures,Azospirillum brasilense Cd formed lateral flagella and fimbriae-like structures which were not observed in shaking liquid cultures. It is suggested that these filaments may play a role in cell-to-cell adhesion of Azospirillum that results in pellicle formation observed in static cultures.
Key wordscationized ferritin extracellular layer fimbriae pellicle formation
Unable to display preview. Download preview PDF.
- Achtman M 1975 Mating aggregation inEscherechia coli conjugation. J. Bact. 123, 505–515.Google Scholar
- Danon D, Goldstein L, Marikovsky Y and Skutelsky E 1972 Use of cationized ferritin as a label of negative charge on cell surfaces. J. Ultrastruct. Res. 38, 500–510.Google Scholar
- Döbereiner J and Day J M 1976 Associative symbiosis in tropical grasses: Characterization of microorganisms and dinitrogen-fixing sites.In Proc. Internat Symp. of Nitrogen Fixation. Eds. W E Newton and C T Wyman. pp 518–538. Washington State University Press, Pullman.Google Scholar
- Dobson W J and Macrae T H 1979 The function of fimbriae inMyxococcus xanthus. II. The role of fimbriae in cell-cell interaction. Can. J. Microbiol. 25, 1359–1372.Google Scholar
- Gafny R, Okon Y and Kapulnik Y 1986 Adsorption ofAzospirillum brasilense to corn roots. Soil Biol. Biochem. 18, 6–13.Google Scholar
- Hall G H and Krieg N R 1983 Swarming ofAzospirillum brasilense on solid medium. Can. J. Microbiol. 29, 1592–1594.Google Scholar
- Luft J H 1961 Improvement in epoxy resin embedding methods. J. Bioph. Biochem. Cytol. 9, 409–414.Google Scholar
- Mulder E G 1975 Physiology and ecology of free-living nitrogen fixing bacteria.In Nitrogen-Fixation in Free-Living Micro-organizms. Ed. W D P Stewart. pp 3–28. Cambridge University Press, London.Google Scholar
- Nur I, Okon Y and Henis Y 1980 Comparative studies of nitrogen-fixing bacteria associated with grasses in Israel withAzospirillum brasilense. Can. J. Microbiol. 26, 714–718.Google Scholar
- Okon Y, Albrecht S L and Burris R H 1976 Carbon and ammonia metabolism ofSpirillum lipoferum. J. Bacter. 128, 592–597.Google Scholar
- Okon Y, Houchins J P, Albrecht S L and Burris R H 1977 Growth ofSpirillum lipoferum at constant partial pressures of oxygen and the properties of its nitrogenase in cell-free extracts. J. Gen. Microbiol. 98, 87–93.Google Scholar
- Old D C, Corneil I, Gibson L F, Thomson A D and Duguid J P 1968 Fimbriation, pellicle formation and amount of growth ofSalmonella in broth. J. Gen. Microbiol. 51, 1–16.Google Scholar
- Sadasivan L and Neyra C A 1985 Flocculation inAzospirillum brasilense andAzospirillum lipoferum: Exopolysaccharides and cyst formation. J. Bacteriol. 163, 716–723.Google Scholar