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Putting a Cell Together
Published in Thomas M. Nordlund, Peter M. Hoffmann, Quantitative Understanding of Biosystems, 2019
Thomas M. Nordlund, Peter M. Hoffmann
Phycobilisomes act as light-harvesting antennae for the photosynthetic bacteria. Pigments bound to the phycobiliproteins are responsible for the blue-green color of most cyanobacteria. Variations are mainly due to carotenoids and phycoerythrins, which give the cells the red-brownish color. The color of the ambient light influences the composition of phycobilisomes in some cyanobacteria: in green light, cells accumulate more phycoerythrin; in red, more phycocyanin. The result is that the bacteria appear green in red light and red in green light, but the importance is that it maximizes use of available light for photosynthesis.
Algae from Extremophilic Conditions and Their Potential Applications
Published in Shashi Kant Bhatia, Sanjeet Mehariya, Obulisamy Parthiba Karthikeyan, Algal Biorefineries and the Circular Bioeconomy, 2022
Ashiwin Vadiveloo, Tasneema Ishika, David Chuka-Ogwude, Mohammadjavad Raeisossadati, Ângelo P. Matos
Certain cyanobacteria, on the other hand, employ different strategies than that of Chlamydomonas due to the absence of light-harvesting chlorophyll proteins. They contain unique phycobilisomes that allow for the improved capture of light at elevated water column depth, within microbial mats or under ice (Vincent et al., 2007). Phycobilisomes are robust light-capturing systems that are found in the photosynthetic membranes of cyanobacteria (Joshua et al., 2005). Most microbial mats on the benthos of ice-covered Antarctic lakes have a pink appearance due to high levels of the phycobiliprotein known as phycoerythrin.
Toward Understanding the Intelligent Properties of Biological Macromolecules
Published in George K. Knopf, Amarjeet S. Bassi, Smart Biosensor Technology, 2018
The phycobiliproteins represent an interesting class of photodynamic proteins that have evolved to function with extremely high light collection efficiency in low-light-level environments, such as deep underwater, where their host algae are often found in highly competitive ecological niches. A closely related family of proteins, the phycobiliproteins—phycoerythrin, phycocyanin, and allophycocyanin—in that order, are found in vivo in supramolecular assemblies in an antenna-like structure called the phycobilisome. Each protein absorbs in its respective region in the visible spectrum and progressively transfers the absorbed light energy with high efficiency (>90% quantum yield) via a Forster-type transfer mechanism down the phycobilisome and into Photosystem II to drive photosynthesis (8). The chromophores found in the individual subunits of the three different phycobiliproteins are variants of open-chain tetrapyrroles coupled to specific protein residues through thioether linkages, as is shown in Figure 2.2. As optical elements, these phycobiliprotein chromophores possess distinct advantages. These include intense fluorescence, nearly 20-fold greater than that of a fluorescein molecule, high quantum yields, and large Stokes shifts—some 2.7-fold greater than that found in fluorescein (9). Because of these desirable properties, some of the phycobiliproteins have found commercial uses as biochemical and biotechnological probes (10). Here we describe experiments that demonstrated they retained their desirable optical properties after being surface immobilized using a number of different biosensor compatible strategies. These include binding to Langmuir–Blodgett (LB) monolayer films, entrapment within optically accessible sol-gel glasses, and binding to conducting polymers immobilized upon optical fiber surfaces. Therefore, phycobiliproteins have potential for use in biomaterials and smart biosensor applications.
Application of algae as low cost and effective bio-adsorbent for removal of heavy metals from wastewater: a review study
Published in Environmental Technology Reviews, 2020
Abolhasan Ameri, Sajad Tamjidi, Faeghe Dehghankhalili, Arezoo Farhadi, Mohammad Amin Saati
Rhodophytes are characterized by their floridean pigments, which are reddened by coating the green chlorophyll. Most Rhodophyta grow near the tropical and subtropical coasts. They are distributed in the world's major oceans and grow mainly in shaded areas with warm and calm water. Red algae are also found in the deepest waters [109]. Phycobilisomes and cyanobacteria enable red algae to photosynthesize even in dim light. Cyanobacteria and red algae have antenna structures that can absorb light at a very low intensity. These antennas are arranged as complexes above the membrane, and membrane processes near the photosystem reaction centres. These complexes, called phycobilisome, are composed of proteins (phycobiliproteins), which are covalently related to phycobilins. Phycobilins are open-chain tetr-apyrroles and are therefore structurally related to chlorophylls [115]. Red algae are one of the oldest plants on earth. It has a simple vascular system, tissues such as leaves and sporangia. Their evolution need the development of a vascular transport system, durable body structure, DNA repair functions and signal transduction capability [116]. Red algae, as a storage product, produce granular as floridean starch in the cytoplasm, which is different from green algae starch. In addition to these unique features, monochromatic red algae are strongly supported by nuclear, plastic and mitochondrial gene trees [117].
Assessment of various colored lights on the growth pattern and secondary metabolites synthesis in Spirulina platensis
Published in Preparative Biochemistry & Biotechnology, 2023
Elnaz Sohani, Farshid Pajoum Shariati, Seyed Ramin Pajoum Shariati
Spirulina platensis is the blue-green cyanobacteria that live in freshwater.[7,20] It is one of the promising cyanobacteria used as commercial products.[21–23] In the Spirulina sp. photosynthesis process, inorganic carbon (CO2) is converted into organic carbon by absorbing light energy.[24,25] These filamentous cyanobacteria produce high-value components, such as proteins, vitamins (B1, B2, B9, B6, and B12), mineral (Se and Magnesium), lipid, pigment (chlorophyll a, Beta-carotene and Phycocyanin), and have antioxidant property potential.[20,26,27] Generally, Arthrospira platensis has ∼28 genes for secondary metabolism biosynthesis, and 959 in cofactors and vitamins metabolism.[25] Many studies have reported that the specific growth rate of Spirulina sp. is dependent on light, nutrition concentration, salinity, temperature, species, and pH, photobioreactors (open and close system), and many other kinds of parameters.[8,20,28] Chlorophyll is the most important photosynthetic pigment found in plants.[29,30] The photosynthetic systems of cyanobacteria shape around chlorophyll a (Chla). They have many essential properties, such as antimutagenic effects, antioxidants capacity to scavenge free radicals, and prevent lipid oxidations. It uses as natural colorant in food.[19,31] Phycobiliproteins (PBP) are pigment binding proteins, water-soluble, synthesized typically by cyanobacteria, cryptophytes, and red algae.[1] There are three main PBP known as phycoerythrin (PE) (absorption maximum peak 540–570 nm), phycocyanin (CPC) (absorption maximum peak 610–620 nm), and allophycocyanin (APC) (absorption maximum peak (650–655 nm).[32,33] It could be utilized as a natural colorant in foods, in the pharmaceutical field as an antioxidant, anti-inflammatory, and neuroprotective. The major photosynthetic organisms of the world oceans, which are the cyanobacteria, absorb light energy by phycobilisome transferring excitation energy to photosynthetic reaction centers. In other words, the light energy absorbed by phycobilisome, which is known as an accessory pigment that stores carbon and nitrogen, transfers to chlorophyll as excitation energy.[32]