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Anabaena sp.PCC 7120

You Chen, Arnaud Taton, Michaela Go, Ross E London, Lindsey M Pieper, Susan S Golden, James W Golden
To facilitate development of synthetic biology tools for genetic engineering of cyanobacterial strains, we constructed pANS-derived self-replicating shuttle vectors that are based on the minimal replication element of the Synechococcus elongatus strain PCC 7942 plasmid pANS. To remove the possibility of homologous recombination events between the shuttle plasmids and the native pANS plasmid, the endogenous pANS was cured through plasmid incompatibility-mediated spontaneous loss. A heterologous toxin-antitoxin cassette was incorporated into the shuttle vectors for stable plasmid maintenance in the absence of antibiotic selection...
October 14, 2016: Microbiology
David Malatinszky, Ralf Steuer, Patrik R Jones
Anabaena sp. PCC 7120 is a nitrogen-fixing filamentous cyanobacterium. Under nitrogen limiting conditions, a fraction of the vegetative cells in each filament terminally differentiate to non-growing heterocysts. Heterocysts are metabolically and structurally specialized to enable O2-sensitive nitrogen fixation. The functionality of the filament, as an association of vegetative cells and heterocysts, is postulated to depend on metabolic exchange of electrons, carbon and fixed nitrogen. In the present work, we compile and evaluate a comprehensive curated stoichiometric model of this two-cell system, with the objective function based on the growth of the filament under diazotrophic conditions...
November 29, 2016: Plant Physiology
Amit Srivastava, Klaus Brilisauer, Ashutosh K Rai, Anand Ballal, Karl Forchhammer, Anil K Tripathi
Alternative sigma factors belonging to the Group 3 are thought to play an important role in the adaptation of cyanobacteria to environmental challenges by altering expression of genes needed for coping with such stresses. In this study, the role of an alternative sigma factor, SigJ, was analyzed in the filamentous nitrogen-fixing cyanobacterium, Anabaena sp. PCC 7120 by knocking down the expression of the sigJ gene (alr0277) employing an anti-sense RNA-mediated approach. In the absence of any stress, the knock-down (KD0277) or the wild-type strain both grew similarly...
November 10, 2016: Plant & Cell Physiology
Ryudo Ohbayashi, Jun-Ya Yamamoto, Satoru Watanabe, Yu Kanesaki, Taku Chibazakura, Shin-Ya Miyagishima, Hirofumi Yoshikawa
Cyanobacteria exhibit light-dependent cell growth since most of their cellular energy is obtained by photosynthesis. In Synechococcus elongatus PCC 7942, one of the model cyanobacterium, DNA replication depends on the photosynthetic electron transport. However, the critical signal for regulatory mechanism of DNA replication has not been identified. In addition, conservation of this regulatory mechanism has not been investigated among cyanobacteria. To understand this regulatory signal and its dependence on light, we examined the regulation of DNA replication under both light and dark condition among three model cyanobacteria, S...
November 10, 2016: Plant & Cell Physiology
Patrick Videau, Orion S Rivers, Kathryn Hurd, Blake Ushijima, Reid T Oshiro, Rachel J Ende, Samantha M O'Hanlon, Loralyn M Cozy
The commitment of differentiating cells to a specialized fate is fundamental to the correct assembly of tissues within a multicellular organism. Because commitment is often irreversible, entry into and progression through this phase of development must be tightly regulated. Under nitrogen-limiting conditions, the multicellular cyanobacterium Anabaena sp. strain PCC 7120 terminally commits ∼10% of its cells to become specialized nitrogen-fixing heterocysts. Although commitment is known to occur 9-14 h after the induction of differentiation, the factors that regulate the initiation and duration of this phase have yet to be elucidated...
October 24, 2016: Proceedings of the National Academy of Sciences of the United States of America
Prashant Kumar Singh, Alok Kumar Shrivastava, Shilpi Singh, Ruchi Rai, Antra Chatterjee, L C Rai
In silico derived properties on experimental validation revealed that hypothetical protein Alr2954 of Anabaena sp. PCC7120 is ADP-ribose pyrophosphatase, which belongs to nudix hydrolase superfamily. Presence of ADP-ribose binding site was attested by ADP-ribose pyrophosphatase activity (K m 44.71 ± 8.043 mM, V max 7.128 ± 0.417 μmol min(-1) mg protein(-1), and K cat/K m 9.438 × 10(4) μM(-)1 min(-1)). Besides ADP-ribose, the enzyme efficiently hydrolyzed various nucleoside phosphatases such as 8-oxo-dGDP, 8-oxo-dADP, 8-oxo-dGTP, 8-oxo-dATP, GDP-mannose, ADP-glucose, and NADH...
October 24, 2016: Functional & Integrative Genomics
Akiyoshi Higo, Atsuko Isu, Yuki Fukaya, Toru Hisabori
In recent years, studies on the development of gene regulation tools in cyanobacteria have been extensively conducted towards efficient production of valuable chemicals. However, there is considerable scope for improving the economic feasibility of production. To improve a recently reported gene induction system using anhydrotetracycline (aTc)-TetR and an endogenous gene repression system using small antisense RNA in the filamentous nitrogen-fixing cyanobacterium Anabaena sp. PCC 7120 (Anabaena), we constructed a positive feedback loop, in which gfp and a small antisense RNA for tetR are controlled by an aTc-inducible promoter...
September 16, 2016: ACS Synthetic Biology
Sergey Kosourov, Gayathri Murukesan, Jouni Jokela, Yagut Allahverdiyeva
The carotenoid composition of the filamentous heterocystous N2-fixing cyanobacterium Calothrix sp. 336/3 was investigated under three conditions: in full medium (non-diazotrophic growth); in the absence of combined nitrogen (diazotrophic growth); and after long-term H2 photoproduction (diazotrophic medium and absence of nitrogen in atmosphere). Anabaena sp. PCC 7120 and its ΔhupL mutant with disrupted uptake hydrogenase were used as reference strains. Analysis of identified carotenoids and enzymes involved in carotenogenesis showed the presence of three distinct biosynthetic pathways in Calothrix sp...
August 12, 2016: Plant & Cell Physiology
Balkrishna Tiwari, Sindhunath Chakraborty, Savita Singh, Arun K Mishra
To understand the mechanism underlying organophosphate pesticide toxicity, cyanobacterium Anabaena PCC 7120 was subjected to varied concentrations (0, 5, 10, 20 and 30 mg L(-1)) of profenofos and the effects were investigated in terms of changes in cellular physiology, genomic template stability and protein expression pattern. The supplementation of profenofos reduced the growth, total pigment content and photosynthetic efficiency of the test organism in a dose dependent manner with maximum toxic effect at 30 mg L(-1)...
November 2016: Journal of Environmental Science and Health. Part. B, Pesticides, Food Contaminants, and Agricultural Wastes
Javier Santamaría-Gómez, Jesús A G Ochoa de Alda, Elvira Olmedo-Verd, Roque Bru-Martínez, Ignacio Luque
tRNAs are charged with cognate amino acids by aminoacyl-tRNA synthetases (aaRSs) and subsequently delivered to the ribosome to be used as substrates for gene translation. Whether aminoacyl-tRNAs are channeled to the ribosome by transit within translational complexes that avoid their diffusion in the cytoplasm is a matter of intense investigation in organisms of the three domains of life. In the cyanobacterium Anabaena sp. PCC 7120, the valyl-tRNA synthetase (ValRS) is anchored to thylakoid membranes by means of the CAAD domain...
2016: Frontiers in Microbiology
Mareike Rudolf, Mara Stevanovic, Chana Kranzler, Rafael Pernil, Nir Keren, Enrico Schleiff
Many cyanobacteria secrete siderophores to sequester iron. Alternatively, mechanisms to utilize xenosiderophores have evolved. The overall uptake systems are comparable to that of other bacteria involving outer membrane transporters energized by TonB as well as plasma membrane-localized transporters. However, the function of the bioinformatically-inferred components is largely not established and recent studies showed a high diversity of the complexity of the uptake systems in different cyanobacteria. Thus, we approached the systems of the filamentous Anabaena sp...
September 2016: Plant Molecular Biology
Caroline Chénard, Jennifer F Wirth, Curtis A Suttle
UNLABELLED: Here we present the first genomic characterization of viruses infecting Nostoc, a genus of ecologically important cyanobacteria that are widespread in freshwater. Cyanophages A-1 and N-1 were isolated in the 1970s and infect Nostoc sp. strain PCC 7210 but remained genomically uncharacterized. Their 68,304- and 64,960-bp genomes are strikingly different from those of other sequenced cyanophages. Many putative genes that code for proteins with known functions are similar to those found in filamentous cyanobacteria, showing a long evolutionary history in their host...
2016: MBio
M A Radtsig, O A Koksharova, V A Nadtochenko, I A Khmel
Diazotrophic cyanobacteria Anabaena sp. PCC 7120, four Nostoc strains, and two Azotobacter species (A. vinelandii and A. chroococcum) were found to produce gold nanoparticles (GNP) under nitrogen fixation conditions. GNP biogenesis occurred at AuHCl₄ concentrations from 0.1 to 1 mM. In the cultures of unicellular cyanobacteria Synechococcus sp. PCC 7942 and Synechocystis incapable of nitrogen fixation, no GNP were formed at the same concentrations of gold salts. The plasmon resonance band peak was located at 552 nm...
January 2016: Mikrobiologiia
Vicente Mariscal, Dennis J Nürnberg, Antonia Herrero, Conrad W Mullineaux, Enrique Flores
Filamentous, N2 -fixing, heterocyst-forming cyanobacteria grow as chains of cells that are connected by septal junctions. In the model organism Anabaena sp. strain PCC 7120, the septal protein SepJ is required for filament integrity, normal intercellular molecular exchange, heterocyst differentiation, and diazotrophic growth. An Anabaena strain overexpressing SepJ made wider septa between vegetative cells than the wild type, which correlated with a more spread location of SepJ in the septa as observed with a SepJ-GFP fusion, and contained an increased number of nanopores, the septal peptidoglycan perforations that likely accommodate septal junctions...
September 2016: Molecular Microbiology
Reza Dastvan, Eva-Maria Brouwer, Denise Schuetz, Oliver Mirus, Enrico Schleiff, Thomas F Prisner
Many proteins of the outer membrane of Gram-negative bacteria and of the outer envelope of the endosymbiotically derived organelles mitochondria and plastids have a β-barrel fold. Their insertion is assisted by membrane proteins of the Omp85-TpsB superfamily. These proteins are composed of a C-terminal β-barrel and a different number of N-terminal POTRA domains, three in the case of cyanobacterial Omp85. Based on structural studies of Omp85 proteins, including the five POTRA-domain-containing BamA protein of Escherichia coli, it is predicted that anaP2 and anaP3 bear a fixed orientation, whereas anaP1 and anaP2 are connected via a flexible hinge...
May 24, 2016: Biophysical Journal
Rocío López-Igual, Adjélé Wilson, Ryan L Leverenz, Matthew R Melnicki, Céline Bourcier de Carbon, Markus Sutter, Aiko Turmo, François Perreau, Cheryl A Kerfeld, Diana Kirilovsky
The photoactive Orange Carotenoid Protein (OCP) is involved in cyanobacterial photoprotection. Its N-terminal domain (NTD) is responsible for interaction with the antenna and induction of excitation energy quenching, while the C-terminal domain is the regulatory domain that senses light and induces photoactivation. In most nitrogen-fixing cyanobacterial strains, there are one to four paralogous genes coding for homologs to the NTD of the OCP. The functions of these proteins are unknown. Here, we study the expression, localization, and function of these genes in Anabaena sp...
July 2016: Plant Physiology
Tylor J Johnson, Jacob D Zahler, Emily L Baldwin, Ruanbao Zhou, William R Gibbons
Cyanobacteria are currently being engineered to photosynthetically produce next-generation biofuels and high-value chemicals. Many of these chemicals are highly toxic to cyanobacteria, thus strains with increased tolerance need to be developed. The volatility of these chemicals may necessitate that experiments be conducted in a sealed environment to maintain chemical concentrations. Therefore, carbon sources such as NaHCO3 must be used for supporting cyanobacterial growth instead of CO2 sparging. The primary goal of this study was to determine the optimal initial concentration of NaHCO3 for use in growth trials, as well as if daily supplementation of NaHCO3 would allow for increased growth...
July 2016: Journal of Microbiological Methods
Patrick Videau, Kaitlyn N Wells, Arun J Singh, William H Gerwick, Benjamin Philmus
Cyanobacteria are well-known producers of natural products of highly varied structure and biological properties. However, the long doubling times, difficulty in establishing genetic methods for marine cyanobacteria, and low compound titers have hindered research into the biosynthesis of their secondary metabolites. While a few attempts to heterologously express cyanobacterial natural products have occurred, the results have been of varied success. Here, we report the first steps in developing the model freshwater cyanobacterium Anabaena sp...
September 16, 2016: ACS Synthetic Biology
Julia Walter, Fiona Lynch, Natalia Battchikova, Eva-Mari Aro, Peter J Gollan
Calcium is integral to the perception, communication and adjustment of cellular responses to environmental changes. However, the role of Ca(2+) in fine-tuning cellular responses of wild-type cyanobacteria under favourable growth conditions has not been examined. In this study, extracellular Ca(2+) has been altered, and changes in the whole transcriptome of Anabaena sp. PCC 7120 have been evaluated under conditions replete of carbon and combined nitrogen. Ca(2+) induced differential expression of many genes driving primary cellular metabolism, with transcriptional regulation of carbon- and nitrogen-related processes responding with opposing trends...
June 2016: Journal of Experimental Botany
Hongjie Qin, Chengrong Peng, Yongding Liu, Dunhai Li
Stratospheric ozone depletion increases the amount of ultraviolet-B radiation (UVBR) (280-320 nm) reaching the surface of the earth, potentially affecting phytoplankton. In this work, Anabaena sp. PCC 7120, a typically nitrogen (N)-fixing filamentous bloom-forming cyanobacterium in freshwater, was individually cultured in N-deficient and N-enriched media for long-term acclimation before being subjected to ultraviolet-B (UVB) exposure experiments. Results suggested that the extent of breakage in the filaments induced by UVBR increases with increasing intensity of UVB stress...
June 2012: Journal of Phycology
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