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Prashant Swapnil, Ashwani K Rai
Soil salinity in nature is generally mixed type; however, most of the studies on salt toxicity are performed with NaCl and little is known about sulfur type of salinity (Na2SO4). Present study discerns the physiologic mechanisms responsible for salt tolerance in salt-adapted Anabaena fertilissima, and responses of directly stressed parent cells to NaCl and NaCl+Na2SO4 mixture. NaCl at 500 mM was lethal to the cyanobacterium, whereas salt-adapted cells grew luxuriantly. Salinity impaired gross photosynthesis, electron transport activities, and respiration in parent cells, but not in the salt-adapted cells, except a marginal increase in PSI activity...
January 19, 2018: Protoplasma
Emiko B Sano, Christopher A Wall, Patrick R Hutchins, Scott R Miller
The conventional view of bacterial adaptation emphasizes the importance of rapidly evolved changes that are highly repeatable in response to similar environments and subject to loss in the absence of selection. Consequently, genetic variation is not expected to persist over long time scales for these organisms. Here, we show that a geographically widespread gene content polymorphism has surprisingly been maintained for tens of millions of years of diversification of the multicellular cyanobacterium Fischerella thermalis...
January 15, 2018: Nature Ecology & Evolution
Amr Badary, Shouhei Takamatsu, Mitsuharu Nakajima, Stefano Ferri, Peter Lindblad, Koji Sode
An important feature offered by marine cyanobacterial strains over freshwater strains is the capacity to grow in seawater, replacing the need for often-limited freshwater. However, there are only limited numbers of marine cyanobacteria that are available for genetic manipulation and bioprocess applications. The marine unicellular cyanobacteria Synechococcus sp. strain NKBG 15041c (NKBG15041c) has been extensively studied. Recombinant DNA technologies are available for this strain, and its genomic information has been elucidated...
January 12, 2018: Marine Biotechnology
Trinity L Hamilton, Judith M Klatt, Dirk de Beer, Jennifer L Macalady
We report the isolation of a pinnacle-forming cyanobacterium isolated from a microbial mat covering the sediment surface at Little Salt Spring-a flooded sinkhole in Florida with a perennially microoxic and sulfidic water column. The draft genome of the isolate encodes all of the enzymatic machinery necessary for both oxygenic and anoxygenic photosynthesis, as well as genes for methylating hopanoids at the C-2 position. The physiological response of the isolate to H2S is complex: (i) no induction time is necessary for anoxygenic photosynthesis; (ii) rates of anoxygenic photosynthesis are regulated by both H2S and irradiance; (iii) O2 production is inhibited by H2S concentrations as low as 1 μM and the recovery rate of oxygenic photosynthesis is dependent on irradiance; (iv) under the optimal light conditions for oxygenic photosynthesis, rates of anoxygenic photosynthesis are nearly double those of oxygenic photosynthesis...
January 12, 2018: ISME Journal
Chang-Lun Shao, Xiao-Feng Mou, Fei Cao, Carmenza Spadafora, Evgenia Glukhov, Lena Gerwick, Chang-Yun Wang, William H Gerwick
We reported previously the discovery of the potent antimalarial 40-membered macrolide bastimolide A (1) from the tropical marine cyanobacterium Okeania hirsute. Continued investigation has led to the discovery of a new analogue, bastimolide B (2), a 24-membered polyhydroxy macrolide with a long aliphatic chain and unique terminal tert-butyl group. Its complete structure was determined by a combination of extensive spectroscopic methods and comparative analysis of its methanolysis products with those of bastimolide A...
January 12, 2018: Journal of Natural Products
Narendran Sekar, Jian Wang, Yan Zhou, Yi Fang, Yajun Yan, Ramaraja P Ramasamy
Cyanobacteria are used as anode catalysts in photo-bioelectrochemical cells to generate electricity in a sustainable, economic and environmental friendly manner using only water and sunlight. Though cyanobacteria (CB) possess unique advantage for solar energy conversion by virtue of its robust photosynthesis, they cannot efficiently perform extracellular electron transfer (EET). The reasons being, unlike dissimilatory metal reducing bacteria (that are usually exploited in microbial fuel cells to generate electricity), (1) CB do not possess any special features on their outer membrane to carry out EET and (2) the electrons generated in photosynthetic electron transport chain are channeled into competing respiratory pathways rather than to the anode...
January 8, 2018: Biotechnology and Bioengineering
Guang Yang, Monica A Cozad, Destin A Holland, Yi Zhang, Hendrik Luesch, Yousong Ding
Mycosporine-like amino acids (MAAs) are secondary metabolites of a variety of marine organisms including cyanobacteria and macroalgae. These compounds have strong ultraviolet (UV) absorption maxima between 310 and 362 nm and are biological sunscreens for counteracting the damaging effects of UV radiation in nature. The common MAA shinorine has been used as one key active ingredient of environmentally friendly sunscreen creams. Commercially used shinorine is isolated from one red algae that is generally harvested from the wild...
January 5, 2018: ACS Synthetic Biology
Ippei Sakamoto, Koichi Abe, Sumiya Kawai, Kaori Tsukakoshi, Yuta Sakai, Koji Sode, Kazunori Ikebukuro
Cyanobacteria are ideal cellular factories for biochemical production because of their ability to fix CO2 by photosynthesis and convert this molecule into biochemicals. Previously, we engineered a riboregulator that enables post-transcriptional gene regulation in the cyanobacterium Synechocystis sp. PCC 6803. Here, we improved the riboregulator by designing two RNA species, taRNA and crRNA, to enhance its induction fold. We inserted nucleotides into the crRNA loop to enhance intermolecular hybridization and successfully improved its induction fold...
January 5, 2018: RNA Biology
Satoru Watanabe, Hiroaki Ozawa, Hiroaki Kato, Kaori Nimura-Matsune, Toshifumi Hirayama, Fumitaka Kudo, Tadashi Eguchi, Katsumi Kakinuma, Hirofumi Yoshikawa
Owing to their photosynthetic capabilities, there is increasing interest in utilizing cyanobacteria to convert solar energy into biomass. 2-Deoxy-scyllo-inosose (DOI) is a valuable starting material for the benzene-free synthesis of catechol and other benzenoids. DOI synthase (DOIS) is responsible for the formation of DOI from d-glucose-6-phosphate (G6P) in the biosynthesis of 2-deoxystreptamine-containing aminoglycoside antibiotics such as neomycin and butirosin. DOI fermentation using a recombinant Escherichia coli strain has been reported, although a carbon source is necessary for high-yield DOI production...
January 3, 2018: Bioscience, Biotechnology, and Biochemistry
David J K Swainsbury, Matthew S Proctor, Andrew Hitchcock, Michaël L Cartron, Pu Qian, Elizabeth C Martin, Philip J Jackson, Jeppe Madsen, Steven P Armes, C Neil Hunter
Intracytoplasmic vesicles (chromatophores) in the photosynthetic bacterium Rhodobacter sphaeroides represent a minimal structural and functional unit for absorbing photons and utilising their energy for the generation of ATP. The cytochrome bc1 complex (cytbc1) is one of the four major components of the chromatophore alongside the reaction centre-light harvesting 1-PufX core complex (RC-LH1-PufX), the light-harvesting 2 complex (LH2), and ATP synthase. Although the membrane organization of these complexes is known, their local lipid environments have not been investigated...
December 29, 2017: Biochimica et Biophysica Acta
Anita Loeschcke, Dennis Dienst, Vera Wewer, Jennifer Hage-Hülsmann, Maximilian Dietsch, Sarah Kranz-Finger, Vanessa Hüren, Sabine Metzger, Vlada B Urlacher, Tamara Gigolashvili, Stanislav Kopriva, Ilka M Axmann, Thomas Drepper, Karl-Erich Jaeger
Cyclic triterpenes constitute one of the most diverse groups of plant natural products. Besides the intriguing biochemistry of their biosynthetic pathways, plant triterpenes exhibit versatile bioactivities, including antimicrobial effects against plant and human pathogens. While prokaryotes have been extensively used for the heterologous production of other classes of terpenes, the synthesis of cyclic triterpenes, which inherently includes the two-step catalytic formation of the universal linear precursor 2,3-oxidosqualene, is still a major challenge...
2017: PloS One
Mahendra Kumar Shukla, Manuel J Llansola-Portoles, Martin Tichý, Andrew A Pascal, Bruno Robert, Roman Sobotka
Cyanobacteria possess a family of one-helix high-light-inducible proteins (HLIPs) that are widely viewed as ancestors of the light-harvesting antenna of plants and algae. HLIPs are essential for viability under various stress conditions, although their exact role is not fully understood. The unicellular cyanobacterium Synechocystis sp. PCC 6803 contains four HLIPs named HliA-D, and HliD has recently been isolated in a small protein complex and shown to bind chlorophyll and β-carotene. However, no HLIP has been isolated and characterized in a pure form up to now...
December 26, 2017: Photosynthesis Research
Peili Jia, Yanping Zhou, Xufeng Zhang, Yi Zhang, Ruihua Dai
Harmful algal blooms in source water are a worldwide issue for drinking water production and safety. UV/H2O2, a pre-oxidation process, was firstly applied to enhance Fe(II) coagulation for the removal of Microcystis aeruginosa [M. aeruginosa, 2.0 (±0.5) × 106 cell/mL] in bench scale. It significantly improved both algae cells removal and algal organic matter (AOM) control, compared with UV irradiation alone (254 nm UVC, 5.4 mJ/cm2). About 94.7% of algae cells were removed after 5 min UV/H2O2 pre-treatment with H2O2 dose 375 μmol/L, FeSO4 coagulation (dose 125 μmol/L)...
December 11, 2017: Water Research
Ziran Xu, Shoubing Wang, Yuanan Wang, Jie Zhang
Atmospheric particulate matter (APM), commonly seen and widely excited in environment, appears great enough to influence the biochemical processes in aquatic microorganisms and phytoplankton. Understanding the response of cyanobacteria to various factors is fundamental for eutrophication control. To clarify the response of cyanobacteria to APM, the effects of PM2.5, PM2.5-10, and PM>10 on Microcystis aeruginosa were researched. Variabilities in cell density, chlorophyll a, soluble protein, malondialdehyde, extracellular activity, and kinetic parameters of alkaline phosphatase were evaluated by lab-cultured experiments...
December 23, 2017: Environmental Science and Pollution Research International
Ginga Shimakawa, Satoru Watanabe, Chikahiro Miyake
A limitation in carbon dioxide (CO₂), which occurs as a result of natural environmental variation, suppresses photosynthesis and has the potential to cause photo-oxidative damage to photosynthetic cells. Oxygenic phototrophs have strategies to alleviate photo-oxidative damage to allow life in present atmospheric CO₂ conditions. However, the mechanisms for CO₂ limitation acclimation are diverse among the various oxygenic phototrophs, and many mechanisms remain to be discovered. In this study, we found that the gene encoding a CO₂ limitation-inducible protein, ColA, is required for the cyanobacterium Synechococcus sp...
December 15, 2017: Marine Drugs
Joseph Robert Piechura, Kapil Amarnath, Erin K O'Shea
The circadian clock interacts with other regulatory pathways to tune physiology to predictable daily changes and unexpected environmental fluctuations. However, the complexity of circadian clocks in higher organisms has prevented a clear understanding of how natural environmental conditions affect circadian clocks and their physiological outputs. Here, we dissect the interaction between circadian regulation and responses to fluctuating light in the cyanobacterium Synechococcus elongatus. We demonstrate that natural changes in light intensity substantially affect the expression of hundreds of circadian-clock-controlled genes, many of which are involved in key steps of metabolism...
December 14, 2017: ELife
Sevgi Ertuğrul Karatay, Gönül Dönmez, Zümriye Aksu
The use of microbial biomass as biosorbent for phenol removal has been extensively studied, but its removal by biosorption by thermophilic cyanobacterium Phormidium sp. has not been investigated to the best of our knowledge. In the present study, some important parameters for biosorption process were optimized, starting with testing the effects of different pH values ranging from 1 to 12, and then initial phenol concentrations of 45.1, 115.3, 181.4, 243.3, 339.9 mg/L on phenol uptake. The efficiency of removal from aqueous solution was higher within the pH 6-8 range, with the maximum of 100% at pH 7 after 24 hours of adsorption time...
December 2017: Water Science and Technology: a Journal of the International Association on Water Pollution Research
Po-Cheng Lin, Rajib Saha, Fuzhong Zhang, Himadri B Pakrasi
Isoprenoids are diverse natural compounds, which have various applications as pharmaceuticals, fragrances, and solvents. The low yield of isoprenoids in plants makes them difficult for cost-effective production, and chemical synthesis of complex isoprenoids is impractical. Microbial production of isoprenoids has been considered as a promising approach to increase the yield. In this study, we engineered the model cyanobacterium Synechocystis sp. PCC 6803 for sustainable production of a commercially valuable isoprenoid, limonene...
December 13, 2017: Scientific Reports
Tomotsumi Fujisawa, Shinji Masuda
Photoreceptor proteins have been used to study how protein conformational changes are induced by alterations in their environments and how their signals are transmitted to downstream factors to dictate physiological responses. These proteins are attractive models because their signal transduction aspects and structural changes can be precisely regulated in vivo and in vitro based on light intensity. Among the known photoreceptors, members of the blue light-using flavin (BLUF) protein family have been well characterized with regard to how they control various light-dependent physiological responses in several microorganisms...
December 12, 2017: Biophysical Reviews
Bo Wang, Carrie Eckert, Pin-Ching Maness, Jianping Yu
Cyanobacteria, genetic models for photosynthesis research for decades, have recently become attractive hosts for producing renewable fuels and chemicals, owing to their genetic tractability, relatively fast growth, and their ability to utilize sunlight, fix carbon dioxide and, in some cases, fix nitrogen. Despite significant advances, there is still an urgent demand for synthetic biology tools in order to effectively manipulate genetic circuits in cyanobacteria. In this study, we have compared a total of 17 natural and chimeric promoters, focusing on expression of the ethylene-forming enzyme (EFE) in the cyanobacterium Synechocystis sp...
December 12, 2017: ACS Synthetic Biology
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