A conserved sequence in tRNA and rRNA promoters of Lactococcus lactis

A tRNA operon (trnA) from Lactococcus lactis consisting of seven tRNA genes and a 5S rRNA gene was cloned and sequenced. Promoter-fusion of the trnA promoter to a promoter-less beta-galactosidase gene of Leuconostoc mesenteroides resulted in high levels of beta-galactosidase activity in L. lactis. Searching for sequences with similarity to the sequence of the promoter region revealed a consensus sequence of promoters preceeding rRNA operons and tRNA operons from Lactococcus species including a not previously described conserved sequence (AGTT).     

Construction and characterization of a phycobiliprotein-less mutant of Synechocystis sp. PCC 6803

A mutant strain of the cyanobacterium Synechocystis PCC 6803, called PAL, (PC-, delta apcAB, delta apcE), lacking phycocyanin, allophycocyanin and the core-membrane linker (Lcm), was constructed. The strain was characterized by absorption and fluorescence spectroscopy. The mutant compensates for the absence of the major PS II antenna by increasing its PS II/PS I ratio. It is stable and grows well albeit more slowly than wild type.