Purification, characterization and comparison of phycoerythrins from three different marine cyanobacterial cultures
ABSTRACT The present study is focused on purification, characterization and comparison of phycoerythrins from three different marine cyanobacterial cultures--hormidium sp. A27 DM, Lyngbya sp. A09 DM and Halomicronema sp. A32 DM. 'Phycoerythrin' was successfully purified and characterized. On SDS-PAGE, the PE purified from all three young cultures showed four bands--corresponding to α and β subunits of each of PE-I and PE-II. However, phycoerythrin purified after prolonged growth of Phormidium sp. A27 DM and Halomicronema sp. A32DM showed only one band corresponding to 14 kDa whereas Lyngbya sp. A09 DM continued to produce uncleaved phycoerythrin. The absorption spectra of purified PEs from all the three young and old cultures showed variations however the fluorescence studies of the purified PEs in all cases gave the emission spectra at around 580 nm. The described work is of great importance to understand the role of phycoerythrin in adapting cyanobacteria to stress conditions.
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ABSTRACT: Complementary chromatic adaptation, a photomorphogenetic response, known to occur in many cyanobacteria, enables them to efficiently absorb prevalent wavelengths of light in the environment. In the present study, we have described the influence of light on phycobiliprotein production in three marine phycoerythrin producing cyanobacterial cultures, namely, Lyngbya sp. A09DM, Phormidium sp. A27DM and Halomicronema sp. A32DM. A comparative study (UV-visible overlay spectra and SDS-PAGE analyses) of phycobiliproteins purified from all the three cultures grown in white, yellow, red and green lights has been confirmed. White light was taken as control. Red and green lights were taken to check their effect on phycocyanin and phycoerythrin production, respectively. Yellow light was studied as its wavelength falls in between green and red light. Lyngbya sp. A09DM was found to be the best chromatically adapting cyanobacterium followed by Halomicronema sp. A32DM. These two cultures can be placed in group III chromatic adaptors. Phormidium sp. A27DM was the least chromatically adapting culture and can be placed in group II chromatic adaptors. The study signifies that even light plays an important role along with nutrient availability in adapting cultures to changing environmental conditions.Acta Physiologiae Plantarum 06/2013; 35(6). DOI:10.1007/s11738-013-1219-8
Conference Paper: MSIM2: mixed-signal short channel IGFET model for circuitsimulations[Show abstract] [Hide abstract]
ABSTRACT: MSIM2 is a physical compact model specifically developed for mixed-signal and analog-intensive circuit simulations in deep sub-micron CMOS technologies. MSIM2 separates the drift and diffusion current components as continuous functions in all all operating regions, and shows superior accuracy and continuity in the subthreshold and moderate inversion regions even for second-order derivatives. It has full temperature scalability (-55°C to 150°C) and geometry scalability (down to 0.25 μm in W and L), and uses less parameters than other advanced models. MSIM2 also includes scalable charge and noise models, and has been verified against various processes from around the worldSemiconductor Conference, 1996., International; 11/1996
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ABSTRACT: C-phycoerythrin was isolated and purified from marine Pseudanabaena sp. using two step chromatographic methods. Phycobiliproteins in the marine Pseudanabaena was extracted in 100 mM phosphate buffer (pH 7.2) and precipitated by salting out. The precipitated C-phycoerythrin was purified by gel filtration with Sephadex G-150, and then it was purified by ion exchange chromatography on DEAE cellulose, which was developed by linear ionic strength gradients. Purified phycoerythrin showed absorption maxima at 568 and 541 nm, and displayed a fluorescence maximum at 578 nm. The absorbance ratio A₅₆₈/A₂₈₀, a criterion for purity (purity ratio) achieved was 6.86. It showed a single band on examination by polyacrylamide gel electrophoresis (PAGE). The polypeptide analysis of the purified C-phycoerythrin by SDS-PAGE demonstrated that it contained two chromophore-carrying subunits. The yield of purified C-phycoerythrin obtained was 13.6 mg/g of the cell dry weight with 47% of yield. Obtaining highly pure C-phycoerythrin allows one to evaluate its fluorescence properties for future applications in biochemical and biomedical research.Protein Expression and Purification 07/2011; 80(2):234-8. DOI:10.1016/j.pep.2011.06.016