The thylakoids of cryptomonads are unique in that their lumens are filled with an electron-dense substance postulated to be phycobiliprotein. In this study, we used an antiserum against phycoerythrin (PE) 545 of Rhodomonas lens (gift of R. MacColl, New York State Department of Health, Albany, NY) and protein A-gold immunoelectron microscopy to localize this light-harvesting protein in cryptomon...

Phycocyanin and phycoerythrin are phycobiliproteins that function as photosynthetic antennae pigments in various types of algae (O'Carra & O'hEocha, 1977). Phytochrome, a related phycobiliprotein, plays an important role in photomorphogenesis in higher plants (Pratt, 1978). The chromophores of these proteins are bilins, which are closely related in structure to each other and to the mammalian b...

Visible absorption spectra are presented for the Azolla caroliniana Willd.-Anabaena azollae Strass. association and the individual partners. Although absorption by the phycobiliproteins of the endophytic cyanobacterium clearly complements the absorption by the fern pigments, their contribution to the absorption spectrum of the association is effectively concealed by the preponderance of the Azo...

Three gene sets encode alpha and beta subunits of the phycobiliprotein phycocyanin (PC) in the filamentous cyanobacterium Fremyella diplosiphon. The cpcB1A1 set (encodes PC1) is constitutively expressed, whereas the cpcB2A2 set (encodes PC2) is expressed only in red light and the cpcB3A3 set (encodes PC3) is expressed only during sulfur-limited growth. Primary pigment mutant strain FdBM1 is cha...

Oligodeoxynucleotides containing CpG motifs have been highlighted as potent Th1 activators. We previously reported that Ag and CpG, when conjugated together, synergistically promoted the Ag-specific Th1 development and inhibited the Th2-mediated airway eosinophilia. In this study, we examined the mechanisms underlying the synergism of the covalent conjugation. The CpG-OVA conjugate enhanced the...

PEB (phycoerythrobilin) is a pink-coloured open-chain tetrapyrrole molecule found in the cyanobacterial light-harvesting phycobilisome. Within the phycobilisome, PEB is covalently bound via thioether bonds to conserved cysteine residues of the phycobiliprotein subunits. In cyanobacteria, biosynthesis of PEB proceeds via two subsequent two-electron reductions catalysed by the FDBRs (ferredoxin-d...

In this study, some physiological and biochemical responses of Synechococcus elongatus to salt stress were investigated. The cyanobactrium was grown in BG-11 medium under different concentrations of NaCl (0, 0.5, 1 M). The results indicated that the growth of S. elongatus was significantly inhibited under salt stress on days 5, 9 and 12. Protein content increased in S. elongatus on day 12 in pr...

C-phycocyanin is a highly valuable phycobiliprotein from Arthrospira platensis. However, its extraction, purification and conservation currently limit commercial use. We review here the most common techniques less conventional methods. Simple incubation in phosphate buffer at neutral pH can give high yields (> 100 mg/g) even protein purity 0.7) if parameters (buffer concentration, temperature, ...

In the non-heterocyst, marine cyanobacterium Trichodesmium nitrogen fixation is confined to the photoperiod and occurs coevally with oxygenic photosynthesis although nitrogenase is irreversibly inactivated by oxygen. In previous studies it was found that regulation of photosynthesis for nitrogen fixation involves Mehler reaction and various activity states with reversible coupling of photosynth...