The phycobiliprotein phycoerythrin was localized in symbiotic and free-living Nostoc of the cycad Cycas using immunocytochemistry. In symbiotic Nostoc, phycoerythrin was associated with the thylakoid membranes of vegetative cells and absent from heterocysts. Similar cellular/subcellular localization was observed between symbiotic Nostoc and the free-living Cycas isolate Nostoc 7422.

The diversity of the endophytic Nostoc symbionts of two thalloid bryophytes, the hornwort Anthoceros fusiformis and the liverwort Blasia pusilla, was examined using the tRNA(Leu) (UAA) intron sequence as a marker. The results confirmed that many different Nostoc strains are involved in both associations under natural conditions in the field. The level of Nostoc diversity within individual bryop...

The present study reports on chromium (VI) tolerance of two cyanobacterial strains Nostoc linckia and Nostoc spongiaeforme isolated from salt affected soils using uni-algal and bi-algal systems. Besides distinct halophilism, the two strains exhibited remarkable tolerance to chromium (VI) and revealed 1.2 to 2.8 times more chlorophyll in the presence of the metal. While phycobilins and carotenoi...

Competition among four symbiotically competent Nostoc strains, colonizing rice roots, was examined using hetR-DGGE (denaturing gradient gel electrophoresis) as strain identification. Although mixed in various combinations, only one strain at a time associated with the rice roots. Nostoc strain 8964:3 was the most competitive and our data suggest that its competitive fitness was dependent on rap...

Recent studies on the electron transfer complex formed by cytochrome f and plastocyanin from Nostoc revealed that both hydrophobic and electrostatic interactions play a role in the process of complex formation. To study the balance between these two types of interactions in the encounter and the final state, the complex between plastocyanin from Phormidium laminosum and cytochrome f from Nostoc...

The present study was carried out in order to examine and characterize the bidirectional hydrogenase in the cyanobacterium Nostoc sp. strain PCC 73102. Southern hybridizations with the probes Av1 and Av3 (hoxY and hoxH, bidirectional hydrogenase small and large subunits, respectively) revealed the occurrence of corresponding sequences in Anabaena variabilis (control), Anabaena sp. strain PCC 71...

The present research aimed to investigate through a polyphasic approach, the differences in morphological and genotypic features of two cyanobacterial strains isolated from paddy fields of northern parts of Iran, belonging to the family Nostocaceae (subsect. IV. I). Based on the reliable identification keys, the two strains were identified as Nostoc ellipsosporum (Desm.) Rabenh. ex Born. et Fla...

Nostoc is widely known for its ability to fix atmospheric nitrogen and the establishment of symbiotic relationship with a wide range of plants from various taxonomic groups. Several strains of Nostoc produce phytohormones that promote growth of its plant partners. Nostoc OS-1 was therefore selected for study because of the presence of putative ipdC gene that encodes a key enzyme to produce Indo...

In symbiotic systems, patterns of symbiont diversity and selectivity are crucial for the understanding of fundamental ecological processes such as dispersal and establishment. The lichen genus Nephroma (Peltigerales, Ascomycota) has a nearly cosmopolitan distribution and is thus an attractive model for the study of symbiotic interactions over a wide range of spatial scales. In this study, we an...

D-Enzyme (4-a-glucanotransferase, EC 2.4.1.25) from cultured sym biotic Nostoc and Chlo­ rella has been partially purified and characterized. The enzyme catalyzes the disproportionation o f m altooligosaccharides and is able to form m altooligosaccharides from soluble starch and D-glucose. The properties o f D -enzym e from Nostoc and Chlorella are similar with respect to substrate specificity,...