Structure and Function of the Golgi Complex in Rice Cells (II. Purification and Characterization of Golgi Membrane-Bound Nucleoside Diphosphatase)

The gene coding for phytoene desaturase of the bacterium Erwinia uredovora (crtI) was inserted into the chromosome of the cyanobacterium Synechococcus PCC7942 strain R2-PIM8. For expression of crtI in the heterologous host, two constructs with different promoters were introduced into Synechococcus. In the first, crtI was fused to the 5[prime] region of the psbA gene of the xanthophycean microalga Bumilleriopsis filiformis. The second construct carried crtI inserted downstream of the neomycin phosphotransferase II gene (nptII) from the transposon Tn5. Expression of crtI under the control of the respective promoter was shown by immunodetection of the gene product. The functionality of the heterologously expressed phytoene desaturase CRTI in the transformants was demonstrated by enzymic assays. The transformants acquired very strong resistance toward the bleaching herbicide norflurazon.     

Carbon supply and 2-oxoglutarate effects on expression of nitrate reductase and nitrogen-regulated genes in Synechococcus sp. strain PCC 7942

Synthesis of nitrate reductase in the unicellular cyanobacterium Synechococcus sp. strain PCC 7942 took place at a slow rate when the cells were incubated without a supply of inorganic carbon, but addition to these cells of CO(2)/bicarbonate or, in a Synechococcus strain transformed with a gene encoding a 2-oxoglutarate permease, 2-oxoglutarate stimulated expression of the enzyme. Induction by 2-oxoglutarate was also observed at the mRNA level for two nitrogen-regulated genes, nir and amt1, but not for the photosystem II D1 protein-encoding gene psbA1. Our results are consistent with a role of 2-oxoglutarate in nitrogen control in cyanobacteria.