Photosynthetic Blue-green Algae Research Articles

Biocatalyst Potential Candidate for Human Welfare

Biocatalysis is known since man knew about brewing which was known since 6000 years. Enzymes from microbial sources were then employed in industries such as production of beer, wine, cheese etc. Nearly 100 years down the lane biocatalysts have been used for chemical transformations. In order to access the repertoire of pharmacological and agrochemicals with high chemoselectivity, regioselectivity, and enantioselectivity, biocatalysis integrates microbiologists, enzymologists, and organic chemists. The usual chemical approach is challenged by the saturation of carbon-carbon double bonds by biocatalysts, as they avoid the usage of organocatalysts or precious metals (in combination with chiral ligands and molecular hydrogen). Since past 30 years they have been used for the synthesis of valuable fine chemicals especially pharmaceuticals. This review gives a brief about microbial biocatalyst including the photosynthetic blue-green algae.

Evaluation of Different Biological Activities of Spirulina platensis Extracts

SPIRULINA is aquatic and photosynthetic blue green algae and it is a good source of c-phycocyanin pigments. It is widely utilized as food supplement because it contains significant amount of proteins. This investigation is an effort to study some of medicinal applications of S. platensis such as antioxidant capacity, antimicrobial, cholesterol- reduction and anticancer. Antimicrobial activity of methanol, acetone, chloroform and petroleum ether extracts of dried S. platensis was assayed against two fungi (Aspergillus flavus and Aspergillus niger) and four bacterial species (Staphylococcus aureus, Bacillus subtilis, Escherichia coli and Salmonella typhimurium). The S. platensis extracts exhibited significant activity against all tested bacteria and fungi. The highest inhibition zone (1.35 ±0.04cm) was observed in acetone extract against S. typhimurium. While, petroleum ether extract of S. platensis was recorded the minimum activities of all tested antimicrobial and the lowest inhibition zone against Staphylococcus aureus (0.52±0.01cm). The antioxidant potential of different solvent extracts clearly that acetone extract of S. platensis showed highest percentage of DPPH (2, 2 diphenyl-1- picrylhydrazyl) scavenging activity (75%) and highest values of phenolic contents (0.562mg/g DW). S. platensis displayed anticancer activity due to the productions of phycocyanin, allophycocyanin and other valuable products. Calf Serum was used to evaluate the potentiality of various S. platensis extracts to control the tumor effects in vitro. The cell proliferation assay showed that petroleum ether extract at a concentration of 125 μg ml-1 for 24hrs, significantly inhibited the growth of the Fetal Calf tumor cells (13% viability).

Towards turbocharged photosynthesis

The development of tobacco plants that are genetically engineered to produce a more efficient form of Rubisco, an enzyme involved in photosynthesis, marks a step towards increasing crop yields. See Letter p.547 Rubisco — a major enzyme assimilating atmospheric CO2 into the biosphere — is an important target for efforts to improve the photosynthetic efficiency of plants. These authors successfully engineered tobacco plants containing a functioning Rubisco from a cyanobacterium. The cyanobacterial (photosynthetic blue–green algae) enzyme has a greater catalytic rate than any 'C3' plant. The lines generated here pave the way for future addition of the remaining components of the cyanobacterial CO2-concentrating mechanism, an important step towards enhancing photosynthetic efficiency and improving crop yields.

Evaluation and sensitivity of cyanobacteria, Nostoc muscorum and Synechococcus PCC 7942 for heavy metals stress – a step toward biosensor

This study attempted to determine the effects of heavy metals on the photosynthetic blue-green algae for their potential to use as a biosensor. The bioaccumulation of metals and its effects on pigments of Nostoc muscorum and Synechococcus PCC 7942 were assessed. The culture was grown in BG 11 liquid medium supplied with different metals like mercury (Hg), lead (Pb), and cadmium (Cd) and incubated (µM 20 concentrations) for 10 days under optimal conditions. The accumulated amounts of metals were determined by atomic absorption spectroscopy (AAS). The stress effects on photosynthetic pigment chlorophyll a (Chl a) were monitored by laser-induced fluorescence (LIF). Bio-concentration factor (BCF) reached a peak in cells on the 2nd day of incubation followed by a gradual reduction. The highest reduction in the pigment concentrations (Chl a and β carotene) was observed at 20 µM L−1 Hg treatment. The results indicate that, cyanobacteria may serve as both potential species to be used as a biosensor and used to clean up heavy metals from contaminated water. These changes were analyzed with the long-term goal of exploiting cyanobacterial cells as biosensors.

Phycobilisomes in Blue-Green Algae

Fifteen species of freshwater blue-green algae, including unicellular, filamentous, and colonial forms, were subjected to a variety of fixatives, fixation conditions, and stains for comparison of the preservation of phycobilisomes. Absorption spectra of the corresponding in vivo and released photosynthetic pigments, in 10 of the species that were maintained in culture, demonstrated the presence of phycocyanin in all 10 species and phycoerythrin in only 2 of them. Spectroscope and electron microscope evidence was obtained for localization of phycobiliproteins in phycobilisomes of Nostoc muscorum. Phycobilisomes were observed in all species examined in situ, strenghening the hypothesis that phycobilisomes are common to all phycobiliprotein-containing photosynthetic blue-green algae.

The respiratory chain of colorless algae: III. Electron microscopy

Electron micrographs of KMnO4-fixed Prototheca zopfii, Polytoma uvella, and Polytomella agilis show the presence of mitochondria with typical discoidal cristae of random orientation, a result expected from their cytochrome content. The mitochondria are usually localized near the outer margin of the cell. All three organisms contain starch granules and proplastid-like structures, both bounded by two membranes. Although Prototheca has been called “a colorless Chlorella,” the existence of significant differences in their ultrastructure makes this classification unlikely. Astasia longa does not contain cytochrome oxidase, but its mitochondria show the same type of ultrastructure as the Chlorophyta, and it too has a eucaryotic cellular structure. The Cyanophyta, Leucothrix mucor, and Vitreoscilla sp. have a typical procaryotic cellular structure, a result consistent with the fact that their respiratory characteristics are like those of the Eubacteria. The cell walls of Leucothrix and Vitreoscilla resemble the cell walls of their procaryotic relatives, the photosynthetic blue-green algae.