SUMMARY: The sheaths of two species of cyanobacteria, (two strains) and (one strain), were studied. Their fine structure showed osmiophilic fibres running parallel to the cell surface. Enriched sheath fractions were obtained from both species in high yields in the phenol/water interphase after hot phenol/water extraction of cell homogenates. The purified sheaths of the two species had similar chemical compositions, with about 50% (of sheath dry weight) neutral sugars (galactose, glucose, mannose, xylose, arabinose, rhamnose, fucose, a 2--methylhexose and an unidentified 2--methyl sugar), 5% amino acids and small amounts of glucosamine and galacturonic acid. The sheath composition was independent of changes in the iron or phosphate content of the culture medium. The sheath was insoluble in water, and its chemical composition remained essentially unchanged on application of drastic extraction methods, including boiling in 2% (w/v) SDS. The sheath bound heavy metals (up to at least 0.7% of sheath dry weight) with the effectiveness (measured as absolute quantities) Fe > Zn > Cu > Ni > Mn > Mo > Co. Ni, Cu, Zn and Fe were highly enriched relative to their concentration in the culture medium. The concentration factors for Mo. Mn, Ca, Na and K were low.


Article metrics loading...

Loading full text...

Full text loading...

This is a required field
Please enter a valid email address
Approval was a Success
Invalid data
An Error Occurred
Approval was partially successful, following selected items could not be processed due to error