Mutants of the cyanobacterium Anabaena variabilis that were capable of increased uptake of glutamine, as compared with that in the parental strains, were isolated. Growth of these mutants and their parental strains was measured in media containing N2, ammonia, or glutamine as a source of nitrogen. All strains grew well with any one of these sources of fixed nitrogen. Much of the glutamine taken...

In oxygenic photosynthetic organisms the PSI-C polypeptide, encoded by the psaC gene, provides the ligands for two [4Fe-4S] centers, FA and FB, the terminal electron acceptors in the photosystem I (PSI) complex. An insertion mutation introduced in the psaC locus of the filamentous cyanobacterium Anabaena variabilis ATCC 29413 resulted in the creation of a mutant strain, T398-1, that lacks the P...

Although it is known that calcium is a very important messenger involved in many eukaryotic cellular processes, much less is known about calcium's role in bacteria. CcbP, a Ca(2+)-binding protein, was isolated from the heterocystous cyanobacterium Anabaena sp. PCC 7120, and the ccbP gene was cloned and inactivated. In the absence of combined nitrogen, inactivation of ccbP resulted in multiple c...

Na(+) strongly promoted HCO(3) (-) transport in Anabaena variabilis. The effect was highly specific to this cation. Kinetic analysis indicated a progressive decrease in the K(m) (HCO(3) (-)) of the transport system with increasing Na(+) concentration. V(max) was also affected. We raise the possibility that the transport is a Na(+)-HCO(3) (-) symport; alternatively, that a Na(+)-H(+) antiport (o...

Some cyanobacteria of the order Nostocales can form akinetes, spore-like dormant cells resistant to various unfavorable environmental fluctuations. Akinetes are larger than vegetative and contain large quantities reserve products, mainly glycogen nitrogen storage polypeptide polymer cyanophycin. enveloped in a thick protective coat containing multilayered structure able germinate into new under...

The present study was aimed to isolate a multiple herbicide resistant strain [(MHR)] of Anabaena variabilis exhibiting resistance against four common rice-field herbicides, viz., Arozin, Alachlor, Butachlor and 2,4-D. The multiple herbicide resistant (MHR) strain was isolated by spontaneous mutational techniques. Of the four spontaneously occurring mutants, Arozin resistant mutant (Ar-R) exhibi...