1,465 results on '"ANABAENA variabilis"'
Search Results
152. Method and Device of Water Contamination Biotests
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Belenky, B. G., Kurochkin, V. E., Panina, L. K., Wrobel, L. C., editor, and Brebbia, C. A., editor
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- 1991
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153. In-depth sequence-function characterization reveals multiple paths to enhance phenylalanine ammonia-lyase (PAL) activity
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A. Ramesh, Nikhil U. Nair, Sigamani Gg, Karishma Mohan, Todd C. Chappell, Krishna Nb, Vikas D. Trivedi, R Pk, and Shetty A
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chemistry.chemical_classification ,biology ,Chemistry ,Mutant ,Active site ,Phenylalanine ammonia-lyase ,biology.organism_classification ,humanities ,Enzyme ,Biochemistry ,Product inhibition ,biology.protein ,Saturated mutagenesis ,Function (biology) ,Anabaena variabilis - Abstract
Phenylalanine ammonia-lyases (PALs) deaminate L-phenylalanine to trans-cinnamic acid and ammonium and have idespread application in chemo-enzymatic synthesis, agriculture, and medicine. In particular, the PAL from Anabaena variabilis (Trichormus variabilis) has garnered significant attention as the active ingredient in Pegvaliase®, the only FDA-approved drug treating classical phenylketonuria (PKU). Although an extensive body of literature exists on structure, substrate-specificity, and catalytic mechanism, protein-wide sequence determinants of function remain unknown, which limits the ability to rationally engineer these enzymes. Previously, we developed a high-throughput screen (HTS) for PAL, and here, we leverage it to create a detailed sequence-function landscape of PAL by performing deep mutational scanning (DMS). Our method revealed 79 hotspots that affected a positive change in enzyme fitness, many of which have not been reported previously. Using fitness values and structure-function analysis, we picked a subset of residues for comprehensive single- and multi-site saturation mutagenesis to improve the catalytic activity of PAL and identified combinations of mutations that led to improvement in reaction kinetics in cell-free and cellular contexts. To understand the mechanistic role of the most beneficial mutations, we performed QM/MM and MD and observed that different mutants confer improved catalytic activity via different mechanisms, including stabilizing first transition and intermediate states and improving substrate diffusion into the active site, and decreased product inhibition. Thus, this work provides a comprehensive sequence-function relationship for PAL, identifies positions that improve PAL activity when mutated and assesses their mechanisms of action.
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- 2021
154. Heavy-metal toxicity in the cyanobacterium anabaena variabilis
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Tatiana Dudnicenco
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biology ,Biochemistry ,Chemistry ,Metal toxicity ,biology.organism_classification ,Anabaena variabilis - Published
- 2021
155. Inorganic Carbon Transport and Accumulation in Cyanobacteria
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Miller, A. G., Codd, Geoff A., editor, Dijkhuizen, Lubbert, editor, and Tabita, F. Robert, editor
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- 1990
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156. DNA transfer into cyanobacteria
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Elhai, Jeff, Thiel, Teresa, Pakrasi, Himadri B., Gelvin, Stanton B., editor, Schilperoort, Robbert A., editor, and Verma, Desh Pal S., editor
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- 1990
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157. Excitation Energy Transfer Among Phycobilisomes from the Phycoerythrin Containing Strain Anabaena variabilis ARM310
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Sai, P. S. Maruthi, Mahajan, Sudha, and Baltscheffsky, M., editor
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- 1990
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158. Expression of a Cyanobacterial Gene Regulated by CO2 Concentration
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Chamot, Dana, Coleman, John R., and Baltscheffsky, M., editor
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- 1990
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159. Purification and Characterization of Phosphoribulokinase from N2 — Fixing Cyanobacterium Nostoc muscorum
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Amla, D. V. and Baltscheffsky, M., editor
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- 1990
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160. Requirement for Phosphoenolpyruvate Carboxylase in a Cyanobacterium
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Luinenburg, I., Coleman, J. R., and Baltscheffsky, M., editor
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- 1990
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161. Oxygen and Nitrogenase In Non-Heterocystous Cyanobacteria
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Gallon, J. R., Ullrich, Wolfram R., editor, Rigano, Carmelo, editor, Fuggi, Amodio, editor, and Aparicio, Pedro J., editor
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- 1990
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162. The Role of Amino Acids in the Regulation of Cyanobacterial Glucose-6-Phosphate Dehydrogenase
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Rowell, P., Simpson, G. G., Ullrich, Wolfram R., editor, Rigano, Carmelo, editor, Fuggi, Amodio, editor, and Aparicio, Pedro J., editor
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- 1990
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163. Photocurrent Generation from Immobilized Anabaena variabilis on the Carbon Soot‐coated Electrode with an Aid of Thionin.
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Kang, Nahye, Lee, Jinhwan, and Kim, Sunghyun
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ANABAENA variabilis , *ANABAENA , *THIONINS , *PEPTIDE antibiotics , *ELECTRODES - Published
- 2018
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164. Photoelectrochemical Coulometric Sensing of Anabaena variabilis Through a Mediated Electron Transfer System
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Sunghyun Kim, Jinhwan Lee, and Hyejun Cho
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Coulometry ,Electron transfer ,biology ,Chemistry ,General Chemistry ,biology.organism_classification ,Photochemistry ,Photosynthesis ,Anabaena variabilis - Published
- 2019
165. Analytical studies on carbohydrates of two cyanobacterial species for enhanced bioethanol production along with poly-β-hydroxybutyrate, C-phycocyanin, sodium copper chlorophyllin, and exopolysaccharides as co-products
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Nirupama Mallick, P.B.S. Bhadoria, and Dipanwita Deb
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chemistry.chemical_classification ,Cyanobacteria ,biology ,Renewable Energy, Sustainability and the Environment ,Starch ,020209 energy ,Strategy and Management ,05 social sciences ,02 engineering and technology ,Carbohydrate ,Phosphate ,biology.organism_classification ,Industrial and Manufacturing Engineering ,Reducing sugar ,chemistry.chemical_compound ,chemistry ,050501 criminology ,0202 electrical engineering, electronic engineering, information engineering ,Microcystis aeruginosa ,Food science ,Cellulose ,0505 law ,General Environmental Science ,Anabaena variabilis - Abstract
In view of the world's immense dependency on non-renewable fossil fuels, the present study explores the prospect of Anabaena variabilis and Microcystis aeruginosa, which represent two distinct groups of cyanobacteria: nitrogen fixers and non fixers, for bioethanol production by analyzing the carbohydrate in their biomass, and maximizing its cellular accumulation inducing nitrate and phosphate stress. Under control condition, reducing sugar constituted 27.6% and 23.4% of the total carbohydrate, followed by glycogen exhibiting contents of 11.6% and 9.7% dry cell weight in the respective species. Cellulose, starch, and hemicellulose were obtained in lower quantities. Although phosphate starvation raised the carbohydrate content to a greater extent, its yield (mg L−1) was severely affected due to the depletion in the biomass. Hence, a biphasic phosphate-starved strategy was implemented generating a maximal carbohydrate content of 63.4% in A. variabilis and 55.1% in M. aeruginosa (compared to 46.2% and 41.4% under control) accompanied by ∼1.3-fold higher yield. Consequently, the bioethanol production in the test cyanobacteria reached 28.2% and 23.9% respectively with ∼1.3-fold higher (volumetric) yield than the control. Analysis of co-products revealed significant production of poly-β-hydroxybutyrate, C-phycocyanin, sodium copper chlorophyllin, and exopolysaccharides, wherein phosphate starvation induced effective stimulation of poly-β-hydroxybutyrate and exopolysaccharides, their yields again enhanced by respective ∼2 and ∼1.4-fold under the biphasic phosphate-starved approach. The present work stands out to be one of its kind comparing the suitability of A. variabilis and M. aeruginosa with an aim to have an overall view on cyanobacteria for bioethanol production by evaluating their carbohydrate profiles under different growth conditions, collectively with the production of various co-products, thus, supporting the bio-refinery concept.
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- 2019
166. Dark and photofermentation H2 production from hydrolyzed biomass of the potent extracellular polysaccharides producing cyanobacterium Nostoc commune and intracellular polysaccharide (glycogen) enriched Anabaena variabilis NIES-2095
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Medhat Elbadry, Deia Abd El-Hady, Wael S. El-Sayed, and Fatthy Mohamed Morsy
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chemistry.chemical_classification ,Rhodobacter ,Clostridium acetobutylicum ,biology ,Renewable Energy, Sustainability and the Environment ,Energy Engineering and Power Technology ,02 engineering and technology ,Dark fermentation ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,biology.organism_classification ,Polysaccharide ,01 natural sciences ,Nostoc commune ,Photofermentation ,0104 chemical sciences ,Fuel Technology ,Clostridium beijerinckii ,chemistry ,Food science ,0210 nano-technology ,Anabaena variabilis - Abstract
The biological H2 production industry would be independent from other industries if it has its own supply of organic materials especially in non-agricultural countries. In this study, acid hydrolyzed biomass of the potent extracellular polysaccharides (EPSs) producing cyanobacterium Nostoc commune and glycogen (as intracellular polysaccharide) enriched Anabaena variabilis NIES-2095 were used as a cheap organic carbon feedstock for biological H2 production by two stages dark fermentation by Escherichia coli strain MWW and Clostridium acetobutylicum DSM-792 or Clostridium beijerinckii DSM-1820 and photofermentation by Rhodobacter capsulatus JCM-21090 under anaerobic conditions. Acid hydrolysis of air dried cyanobacterial biomass was conducted at optimum conditions of 4 M HCl at 120 °C in an autoclave for 30 min and subsequently neutralized and used as an organic carbon source for first stage dark fermentation followed by a second stage photofermentation. The facultative anaerobe Escherichia coli strain MWW was used for maintaining anaerobiosis. Escherichia coli strain MWW was isolated and identified by morphological and biochemical characterizations as well as molecular biological phylogenetic analysis of its 16S rDNA sequence. Nostoc commune was identified by morphological and microscopic characterizations and by 16S rDNA sequence phylogenetic analysis. The two stages dark fermentation by Escherichia coli and Clostridium acetobutylicum or Clostridium beijerinckii and photofermentation by Rhodobacter capsulatus produced in total 5.9 and 5.6 mol H2/mole reducing sugars of acid hydrolyzed Nostoc commune EPSs/biomass, respectively and 5.43 and 5 mol H2/mole reducing sugars of acid hydrolyzed biomass of glycogen enriched Anabaena variabilis, respectively. These results indicate a high potency of using cyanobacterial polysaccharides/biomass (extracellular polysaccharides and intracellular glycogen) as an organic carbon source for H2 production which would be of importance for non-agricultural countries.
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- 2019
167. Microbial amperometric biosensor for online herbicide detection: Photocurrent inhibition of Anabaena variabilis
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Andrea Schievano, Shelley D. Minteer, Matteo Grattieri, Pierangela Cristiani, and Matteo Tucci
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Photocurrent ,Detection limit ,Chromatography ,Electrolysis of water ,biology ,General Chemical Engineering ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,biology.organism_classification ,01 natural sciences ,0104 chemical sciences ,chemistry.chemical_compound ,Electron transfer ,chemistry ,Electrochemistry ,medicine ,Atrazine ,0210 nano-technology ,Biosensor ,Activated carbon ,medicine.drug ,Anabaena variabilis - Abstract
A microbial biosensor based on the cyanobacteria Anabaena variabilis was developed for online herbicide detection through inhibition of generated photocurrent. Specifically, atrazine and diuron were employed as model photosynthesis-inhibiting herbicides. To fabricate the biosensor, bacterial cells were immobilized on a carbon felt electrode using alginate as an entrapping polymer and p-benzoquinone (BQ) as the redox mediator to sustain the electron transfer. The current generated by the photo-bioelectrocatalytic oxidation of water was evaluated. During the calibration, an immediate concentration-dependent decrease of the photocurrent was observed after the injection of the tested herbicides. The biosensor showed a sensitivity of −24.6 μA μM−1 cm−2 towards atrazine up to 0.56 μM. As diuron is a much stronger photosynthesis inhibitor, the biosensor allows only turn on/turn off detection for this compound. In order to avoid the release of the mediator in solution, the encapsulation of BQ in the polymer was tested. Addition of activated carbon was necessary to create a conductive network inside the alginate matrix, enabling to achieve a sensitivity of −7.7 μA μM−1 cm−2 towards atrazine up to 131 μM (lower limit of detection 64 nM). Therefore, not only the entrapment prevented the release of BQ in solution, but improved the operating range of the sensor, with a limited decrease of sensitivity that does not hinder its application. These characteristics make the biosensor suitable for environmental analysis, opening for the on-line monitoring of herbicides.
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- 2019
168. A novel method to recover microalgae by compound buoyant-bead flotation
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Kaiwei Xu, Yating Xue, Wenwen Xie, Shuangfeng Zhao, Yanpeng Li, Hao Wen, and Xiaotong Zou
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Flocculation ,biology ,Chemistry ,Chlorella vulgaris ,Filtration and Separation ,02 engineering and technology ,021001 nanoscience & nanotechnology ,biology.organism_classification ,Pulp and paper industry ,Analytical Chemistry ,020401 chemical engineering ,Scenedesmus obliquus ,Cenosphere ,Fly ash ,Microcystis aeruginosa ,Response surface methodology ,0204 chemical engineering ,0210 nano-technology ,Anabaena variabilis - Abstract
To improve the recovery efficiency of buoyant-bead flotation (BBF), a novel compound buoyant-bead flotation technology (CBBF) using acidified fly ash cenospheres with heat-aided pre-flocculation was developed. The effects of cenospheres concentration (0.6–3 g L−1), flotation time (5–20 min) and pH values (2–10) were studied. Response Surface Methodology was utilized to optimize the CBBF process. The results showed that pH value had the greatest influence on the recovery process. When pH values were low, the Chlorella vulgaris (C. vulgaris) cells began to flocculate, which helped to form the “C. vulgaris-cenosphere” aggregates and improved the recovery efficiency. To avoid the addition of flocculants, heat-aided pretreatment was used to promote flocculation process. The maximum recovery efficiency (93.04 ± 0.60%) was obtained at cenospheres concentration of 2.83 g L−1, pH value of 2.41, flotation time of 17.05 mins and flotation temperature of 90 °C. Furthermore, it was demonstrated that this CBBF method can be also widely applied to other microalgae strains, such as Scenedesmus obliquus, Spirulina platensis, Microcystis aeruginosa and Anabaena variabilis. It can be concluded that the CBBF technology is a feasible and highly efficient (over than 90%) process for the removal of various microalgae.
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- 2019
169. Decoupling a novel Trichormus variabilis-Synechocystis sp. interaction to boost phycoremediation
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Omid Tavakoli, Hassan Jalili, H. Christopher Greenwell, Ian Cummins, Fatemeh Razi Astaraei, Sepideh Abedi, Stephen Chivasa, and Barat Ghobadian
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0301 basic medicine ,Conservation of Natural Resources ,Nitrogen ,Industrial Waste ,lcsh:Medicine ,Fresh Water ,Wastewater ,Raw material ,Waste Disposal, Fluid ,Article ,Phosphates ,Industrial wastewater treatment ,03 medical and health sciences ,chemistry.chemical_compound ,0302 clinical medicine ,Nitrate ,Anabaena variabilis ,Microalgae ,Humans ,Ammonium ,Biomass ,lcsh:Science ,Effluent ,Nitrates ,Multidisciplinary ,biology ,Synechocystis ,lcsh:R ,biology.organism_classification ,Pulp and paper industry ,Biodegradation, Environmental ,030104 developmental biology ,chemistry ,Water Resources ,lcsh:Q ,Monoculture ,030217 neurology & neurosurgery - Abstract
To conserve freshwater resources, domestic and industrial wastewater is recycled. Algal systems have emerged as an efficient, low-cost option for treatment (phycoremediation) of nutrient-rich wastewater and environmental protection. However, industrial wastewater may contain growth inhibitory compounds precluding algal use in phycoremediation. Therefore, extremophyte strains, which thrive in hostile environments, are sought-after. Here, we isolated such an alga - a strain of Synechocystis sp. we found to be capable of switching from commensal exploitation of the nitrogen-fixing Trichormus variabilis, for survival in nitrogen-deficient environments, to free-living growth in nitrate abundance. In nitrogen depletion, the cells are tethered to polysaccharide capsules of T. variabilis using nanotubular structures, presumably for nitrate acquisition. The composite culture failed to establish in industrial/domestic waste effluent. However, gradual exposure to increasing wastewater strength over time untethered Synechocystis cells and killed off T. variabilis. This switched the culture to a stress-acclimated monoculture of Synechocystis sp., which rapidly grew and flourished in wastewater, with ammonium and phosphate removal efficiencies of 99.4% and 97.5%, respectively. Therefore, this strain of Synechocystis sp. shows great promise for use in phycoremediation, with potential to rapidly generate biomass that can find use as a green feedstock for valuable bio-products in industrial applications.
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- 2019
170. Growth and secretome analysis of possible synergistic interaction between green algae and cyanobacteria
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Jayant K. Tripathi, Kshipra Gautam, Durlubh K. Sharma, and Ashwani Pareek
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Microbiological Techniques ,0106 biological sciences ,0301 basic medicine ,Cyanobacteria ,Nitrogen ,Nitrogen assimilation ,Bioengineering ,01 natural sciences ,Applied Microbiology and Biotechnology ,03 medical and health sciences ,chemistry.chemical_compound ,Chlorophyta ,Nitrogen Fixation ,010608 biotechnology ,Botryococcus braunii ,Metabolomics ,Biomass ,Secretory Pathway ,biology ,Chemistry ,Triacontanol ,Lipid metabolism ,Lipid Metabolism ,biology.organism_classification ,Lipids ,Coculture Techniques ,030104 developmental biology ,Biochemistry ,Metabolome ,Nitrogen fixation ,Carbohydrate Metabolism ,Microbial Interactions ,Green algae ,Chlorella vulgaris ,Biotechnology ,Anabaena variabilis - Abstract
Synergistic coexistence of nitrogen fixing cyanobacteria such as Anabaena variabilis, Nostoc muscorum and Westiellopsis prolifica with green algae namely Scenedesmus obliquus, Chlorella vulgaris and Botryococcus braunii was studied under nitrogen deficient conditions. The effect of these interactions was investigated on growth, fixed nitrogen content, lipid content and their secretomes in individual cultures and cocultures. Based on the cocultivation studies, it was found that out of the nine interactions studied, B. braunii-N. muscorum synergism was best established. This interaction resulted in a maximum of 50% enhancement in nitrogen fixation in B. braunii-N. muscorum co-culture leading to 27% enhancement in lipid content (membrane and neutral lipid). In general, B. braunii co-cultures showed an enhancement in biomass content of up to 38%. Secretome analysis showed presence of new and modified secondary metabolites having roles in quorum sensing/quenching, interspecies signaling, N-fixation, carbon metabolism, lipid metabolism, antimicrobial activity. Compounds such as trichloroacetic acid and hexadecane were identified that are known to have roles in nitrogen assimilation and carbon metabolism, respectively, were present in some of the co-culture secretomes. The combination of B. braunii-N. muscorum led to the formation of new compounds such as triacontanol which have role in improvement of glucose-lipid metabolism and 9-octadecenamide that is known to be a phytohormone.
- Published
- 2019
171. The Selective Inhibitory Activity of a Fusaricidin Derivative on a Bloom-Forming Cyanobacterium, Microcystis sp
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Chi-Yong Ahn, Seung-Hwan Park, Ankita Srivastava, Young Ki Lee, Hee-Mock Oh, and So-Ra Ko
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chemistry.chemical_classification ,Cyanobacteria ,biology ,General Medicine ,Microcystin ,biology.organism_classification ,Applied Microbiology and Biotechnology ,chemistry.chemical_compound ,chemistry ,Biochemistry ,Microcystis ,Microcystis aeruginosa ,Growth inhibition ,Paenibacillus polymyxa ,Bacteria ,Biotechnology ,Anabaena variabilis - Abstract
Fusaricidin analogs, produced by Paenibacillus polymyxa, were tested for selective control of a major bloom-forming cyanobacterium, Microcystis sp. Fusaricidin (A and B mixtures) and four analogs were isolated from P. polymyxa E681 and investigated for their inhibition of cyanobacterial cell growth. Among the four fusaricidin analogs, fraction 915 Da (designated as Fus901) showed growth inhibition activity for Microcystis aeruginosa but not for Anabaena variabilis and Scenedesmus acutus. Microcystin concentration decreased up to 70% and its content per cell also decreased over 50% after 3 days. Fusaricidin exhibited growth inhibition against Gram-positive bacteria but Fus901 did not. Molecular weights of fusaricidin A and B were 883 Da and 897 Da, whereas that of Fus901 was 915 Da. Structure analysis by a ringopening method revealed a linear form for Fus901. Expression of the pod gene related to oxidative stress was increased 2.1-fold by Fus901 and that of mcyD decreased up to 40%. These results indicate that Fus901 exerts oxidative stress against M. aeruginosa. Thus, Fus901 can be used as a selective cyanobactericide without disturbing the ecological system and could help in decreasing the microcystin concentration.
- Published
- 2019
172. Spectral microscopic imaging of heterocysts and vegetative cells in two filamentous cyanobacteria based on spontaneous Raman scattering and photoluminescence by 976 nm excitation
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Shigeichi Kumazaki and Kouto Tamamizu
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0106 biological sciences ,0301 basic medicine ,Cyanobacteria ,food.ingredient ,Cytological Techniques ,Arabidopsis ,Biophysics ,Rivularia ,Spectrum Analysis, Raman ,Thylakoids ,01 natural sciences ,Biochemistry ,03 medical and health sciences ,symbols.namesake ,food ,Chlorophyta ,Phycobilisomes ,Cellular Senescence ,Photosystem ,Heterocyst ,biology ,Chemistry ,Chlorophyll A ,Cell Biology ,biology.organism_classification ,030104 developmental biology ,Thylakoid ,Luminescent Measurements ,symbols ,Phycobilisome ,Raman scattering ,010606 plant biology & botany ,Anabaena variabilis - Abstract
Photosynthetic pigment-protein complexes are highly concentrated in thylakoid membranes of chloroplasts and cyanobacteria that emit strong autofluorescence (mainly 600–800 nm). In Raman scattering microscopy that enables imaging of pigment concentrations of thylakoid membranes, near infrared laser excitation at 1064 nm or visible laser excitation at 488–532 nm has been often employed in order to avoid the autofluorescence. Here we explored a new approach to Raman imaging of thylakoid membranes by using excitation wavelength of 976 nm. Two types of differentiated cells, heterocysts and vegetative cells, in two diazotrophic filamentous cyanobacteria, Anabaena variabilis, and Rivularia M-261, were characterized. Relative Raman scattering intensities of phycobilisomes of the heterocyst in comparison with the nearest vegetative cells of Rivularia remained at a significantly higher level than those of A. variabilis. It was also found that the 976 nm excitation induces photoluminescence around 1017–1175 nm from the two cyanobacteria, green alga (Parachlorella kessleri) and plant (Arabidopsis thaliana). We propose that this photoluminescence can be used as an index of concentration of chlorophyll a that has relatively small Raman scattering cross-sections. The Rivularia heterocysts that we analyzed were clearly classified into at least two subgroups based on the Chla-associated photoluminescence and carotenoid Raman bands, indicating two physiologically distinct states in the development or aging of the terminal heterocyst.
- Published
- 2019
173. Evaluation and characterization of the plant growth promoting potentials of two heterocystous cyanobacteria for improving food grains growth
- Author
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S. Soundararajan, S. Elavarasi, A. Suresh, Nooruddin Thajuddin, and F. Lewis Oscar
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Cyanobacteria ,chemistry.chemical_classification ,biology ,Biofertilizer ,fungi ,food and beverages ,Bioengineering ,biology.organism_classification ,Applied Microbiology and Biotechnology ,Crop ,Dry weight ,chemistry ,Germination ,Auxin ,Botany ,Soil fertility ,Agronomy and Crop Science ,Food Science ,Biotechnology ,Anabaena variabilis - Abstract
Cyanobacteria are potential prokaryotes found in diverse environment of freshwater and marine water ecosystem. They are well known applicant practised in ancient agriculture technique for improving the soil fertility, water holding capacity and texture of the soil. The availability, low cost and fast growth has considered them as superior candidate for biotechnological applications. In the recent years, cyanobacteria are been used to produce plant growth promoting hormones or substances for facilitating effective plant growth. The present study is focussed on validating the plant growth promoting ability of two heterocystous cyanobacteria strains (Anabaena variabilis, Nostoc calcicola) in five crop plant. The cyanobacterial strains were characterized by biochemical and plant growth promoting parameters like Chlorophyll content and IAA production. As result of this study, in vitro experiments revealed 100% of seed germination by Cyanobacteria growth promoting substances (CGPS) of Anabaena variabilis in the grains of Zea mays and Sorghum bicolour, while 90% germination in Nostoc calcicola. Statistical analysis proved the growth root length, plant height, weight of fresh and dry root, number of leaves in CGPS treated and untreated plant in pot. Further the CGPS was characterized using thin-layer chromatography (TLC), FT-IR and HPLC analysis. The dominant auxins in the two isolates were IAA in the range of 0.0372–1.2327 μg g−1 dry weight was detected. However, IAA production by Anabaena variabilis proved as potential candidate for promoting plant growth. In addition, Anabaena variabilis can also be utilized as a biofertilizer for the crops cultivated in normal fields.
- Published
- 2019
174. Long term diazotrophic cultivation induces phycobiliprotein production in Anabaena variabilis IMU8
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Mohammed Fadhil Haddad, Tugba Dayioglu, Barbaros Nalbantoğlu, and Turgay Cakmak
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biology ,Phycobiliprotein ,Botany ,General Medicine ,Diazotroph ,biology.organism_classification ,Anabaena variabilis - Published
- 2019
175. Two Acyl-Lipid Δ9 Desaturase Genes of the Cyanobacterium, Synechococcus SP. Strain PCC7002
- Author
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Sakamoto, T., Stirewalt, V. L., Bryant, D. A., Williams, John Peter, editor, Khan, Mobashsher Uddin, editor, and Lem, Nora Wan, editor
- Published
- 1997
- Full Text
- View/download PDF
176. Low-Temperature Resistance of Higher Plants is Significantly Enhanced by a Non-Specific Δ9 Desaturase from Cyanobacteria
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Ishizaki-Nishizawa, Osamu, Fujii, Toshio, Ohtani, Takeshi, Toguri, Toshihiro, Williams, John Peter, editor, Khan, Mobashsher Uddin, editor, and Lem, Nora Wan, editor
- Published
- 1997
- Full Text
- View/download PDF
177. Comparative studies on growth and Pb(II) removal from aqueous solution by Nostoc muscorum and Anabaena variabilis
- Author
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Gomaa A. Bakeer, Mohamed E. Abuarab, Reham M. El-Bahbohy, Shady Abdel Mottaleb, and Mona Mohamed Abd El-Hameed
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Cyanobacteria ,Chlorophyll a ,Health, Toxicology and Mutagenesis ,Wastewater ,010501 environmental sciences ,01 natural sciences ,Water Purification ,Industrial wastewater treatment ,chemistry.chemical_compound ,0404 agricultural biotechnology ,Algae ,Anabaena variabilis ,Biomass ,Incubation ,Carotenoid ,0105 earth and related environmental sciences ,chemistry.chemical_classification ,Aqueous solution ,biology ,Chlorophyll A ,Public Health, Environmental and Occupational Health ,04 agricultural and veterinary sciences ,General Medicine ,biology.organism_classification ,040401 food science ,Pollution ,Lead ,chemistry ,Environmental chemistry ,Water Pollutants, Chemical ,Nostoc muscorum - Abstract
Industrial wastewater containing heavy metals is a major environmental problem that needs to be treated. This study reported the ability of two fresh water algae cyanobacteria (Nostoc muscorum and Anabaena variabilis) to remove lead from aqueous solutions of four different initial concentrations (0–50 mg/L−1) for 21 days under controlled laboratory conditions. Results obtained in this study showed a maximum removal of Pb(II) (97.8%) by N. muscorum at 15 mg/L−1 initial metal concentration however the maximum removal by A. variabilis at the same concentration was 71.4% after 16 day of incubation. These N. muscorum appeared to be more efficient than A. variabilis for removing Pb(II). Algal growth, pigments in the algae cells were measured during incubation period. Lower concentrations of lead increased biomass, OD, chlorophyll a and carotenoids in both algae. On the other hand, higher concentrations of lead were inhibitory for growth.
- Published
- 2018
178. The ferredoxin-encoding fdxN gene of the filamentous cyanobacterium Anabaena variabilis ATCC 29413 is not essential for nitrogen fixation
- Author
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Kirsten Görlitz, Herbert Böhme, Britta Moslerand, Ursula Monnerjahn, and Bernd Masepohl
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Gene product ,Biochemistry ,biology ,Physiology ,Anabaena ,Nitrogenase ,Plant Science ,biology.organism_classification ,Gene ,Ferredoxin ,Homology (biology) ,Anabaena variabilis ,Heterocyst - Abstract
summary In contrast to that of Anabaena sp. PCC7120, the fdxN gene in Anabaena variabilis ATCC 29413 is not interrupted by a 55-kb DNA element, making this strain more suitable for genetic analysis of fdxN independent of the developmentally regulated excision during heterocyst formation. As a basis for mutational analysis, the fdxN gene of A. variabilis was cloned and sequenced. The deduced FdxN protein sequence was highly homologous to the Anabaena 7120 fdxN gene product including eight cysteine residues that are known to be conserved among ferredoxins containing two [4Fe-4S] clusters. The fdxN gene of A. variabilis was disrupted by insertion of an interposon within the fdxN coding region resulting in mutant strain KG29. Diazotrophic growth and in vivo nitrogenase activity of KG29 were similar to those of the wild-type, indicating that FdxN was not essential for N2 fixation in A. variabilis.
- Published
- 2021
179. Galactosylacylglycerol O-acyltransferase
- Author
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Schomburg, Dietmar, Stephan, Dörte, Schomburg, Dietmar, editor, and Stephan, Dörte, editor
- Published
- 1996
- Full Text
- View/download PDF
180. Using immobilized cyanobacteria and culture medium contaminated with ammonium for H2 production in a hollow-fiber photobioreactor.
- Author
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Markov, Sergei A., Protasov, Eugenii S., Bybin, Victor A., Eivazova, Elvira R., and Stom, Devard I.
- Subjects
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AMMONIUM , *ENCAPSULATION (Catalysis) , *CYANOBACTERIA , *HYDROGEN production , *HOLLOW fibers , *PHOTOBIOREACTORS - Abstract
An inorganic culture medium contaminated with ammonium was used to generate molecular hydrogen by cyanobacteria. First, ammonium ion uptake by immobilized on hollow fibers cells of cyanobacterium Anabaena variabilis was studied in flasks and in a photobioreactor. Next, after the ammonium was removed from water, H 2 production by hollow fibers-immobilized cyanobacterial cells was investigated in flasks and in a photobioreactor. The photobioreactor was designed so that the growth medium with ammonium from a medium reservoir (where ammonium ion concentration was measured) was cycled through a photobioreactor column with hollow fiber-attached cells. The ammonium ion uptake efficiency by attached cells in the photobioreactor was found to be 90% after 25 days. The depletion of the ammonium in water inside a photobioreactor stimulated H 2 production by cyanobacteria which was observed at an average rate of 18 mL·g dw −1 ·h −1 for three months. [ABSTRACT FROM AUTHOR]
- Published
- 2015
- Full Text
- View/download PDF
181. nTiO2 induced changes in intracellular composition and nutrient stoichiometry in primary producer — cyanobacteria.
- Author
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Cherchi, Carla, Miljkovic, Milos, Diem, Max, and Gu, April Z.
- Subjects
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TITANIUM dioxide , *CYANOBACTERIA , *ENVIRONMENTAL engineering , *FOURIER transform infrared spectroscopy , *NUCLEIC acids , *CARBOHYDRATES - Abstract
The widely and increasing use of nano-titanium dioxide (nTiO 2 ) has led to its release in the environment and concerns of consequent impact on aquatic eco-relevant biota. Previous studies indicated possible physiological changes (i.e., nitrogen storage) induced by nano-titanium dioxide (nTiO 2 ) exposure in algae, which will likely have ecological implications. This study investigated the short- (96 h) and long-term (21 days) ecotoxic impact of environmentally relevant nTiO 2 concentrations on the cellular biochemical pools and nutrient stoichiometry in the nitrogen-fixing cyanobacteria Anabaena variabilis . Changes in nutrient element ratios and cellular composition were analyzed using both chemical elemental analysis and Fourier Transform Infrared (FT-IR) spectroscopy. Chemical elemental analysis showed that exposure to nTiO 2 at varying dose concentrations and exposure duration led to statistically significant changes in intracellular C:N, C:P and N:P stoichiometries compared with those in the controls. In general, there seemed to be a decreasing trends of cellular C:N ratio and increase in the cellular C:P and N:P ratios with the increasing level of nTiO 2 exposure. Further FT-IR analysis results revealed both temporal and dose-dependent change patterns of major macromolecules, including protein, lipids, nucleic acids and carbohydrates, in A. variabilis upon nTiO 2 exposure. The relative ratio of amide II, lipids, nucleic acids and carbohydrates to the cellular protein content (quantified as amide I stretch) changed significantly within the initial 96 h of exposure and, both the magnitude of changes and levels of recovery seemed to be nTiO 2 dose-dependent. This study, for the first time, demonstrated that the intracellular composition and nutrient stoichiometry changes could be induced by long-term and short-term exposures to nTiO 2 to primary producers, which may have ecological implications for interspecies equilibriums and community dynamics in aquatic ecosystems. [ABSTRACT FROM AUTHOR]
- Published
- 2015
- Full Text
- View/download PDF
182. Role of RNA Secondary Structure and Processing in Stability of the nifH1 Transcript in the Cyanobacterium Anabaena variabilis.
- Author
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Pratte, Brenda S., Ungerer, Justin, and Thiel, Teresa
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ANABAENA variabilis , *HETEROCYSTS , *CYANOBACTERIA , *GENE expression , *MOLECULAR genetics - Abstract
In the cyanobacterium Anabaena variabilis ATCC 29413, aerobic nitrogen fixation occurs in micro-oxic cells called heterocysts. Synthesis of nitrogenase in heterocysts requires expression of the large nif1 gene cluster, which is primarily under the control of the promoter for the first gene, nifB1. Strong expression of nifH1 requires the nifB1 promoter but is also controlled by RNA processing, which leads to increased nifH1 transcript stability. The processing of the primary nifH1 transcript occurs at the base of a predicted stem-loop structure that is conserved in many heterocystous cyanobacteria. Mutations that changed the predicted secondary structure or changed the sequence of the stem-loop had detrimental effects on the amount of nifH1 transcript, with mutations that altered or destabilized the structure having the strongest effect. Just upstream from the transcriptional processing site for nifH1 was the promoter for a small antisense RNA, sava4870.1. This RNA was more strongly expressed in cells grown in the presence of fixed nitrogen and was downregulated in cells 24 h after nitrogen step down. A mutant strain lacking the promoter for sava4870.1 showed delayed nitrogen fixation; however, that phenotype might have resulted from an effect of the mutation on the processing of the nifH1 transcript. The nifH1 transcript was the most abundant and most stable nif1 transcript, while nifD1 and nifK1, just downstream of nifH1, were present in much smaller amounts and were less stable. The nifD1 and nifK1 transcripts were also processed at sites just upstream of nifD1 and nifK1. [ABSTRACT FROM AUTHOR]
- Published
- 2015
- Full Text
- View/download PDF
183. The composition of the global and feature specific cyanobacterial core-genomes.
- Author
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Simm, Stefan, Keller, Mario, Selymesi, Mario, and Schleiff, Enrico
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CYANOBACTERIA ,PROKARYOTIC genomes ,BACTERIAL outer membrane proteins ,HETEROCYSTS ,ANABAENA variabilis - Abstract
Cyanobacteria are photosynthetic prokaryotes important for many ecosystems with a high potential for biotechnological usage e.g., in the production of bioactive molecules. Either asks for a deep understanding of the functionality of cyanobacteria and their interaction with the environment. This in part can be inferred from the analysis of their genomes or proteomes. Today, many cyanobacterial genomes have been sequenced and annotated. This information can be used to identify biological pathways present in all cyanobacteria as proteins involved in such processes are encoded by a so called core-genome. However, beside identification of fundamental processes, genes specific for certain cyanobacterial features can be identified by a holistic genome analysis as well. We identified 559 genes that define the core-genome of 58 analyzed cyanobacteria, as well as three genes likely to be signature genes for thermophilic and 57 genes likely to be signature genes for heterocyst-forming cyanobacteria. To get insights into cyanobacterial systems for the interaction with the environment we also inspected the diversity of the outer membrane proteome with focus on b-barrel proteins. We observed that most of the transporting outer membrane b-barrel proteins are not globally conserved in the cyanobacterial phylum. In turn, the occurrence of b-barrel proteins shows high strain specificity. The core set of outer membrane proteins globally conserved in cyanobacteria comprises three proteins only, namely the outer membrane b-barrel assembly protein Omp85, the lipid A transfer protein LptD, and an OprB-type porin. Thus, we conclude that cyanobacteria have developed individual strategies for the interaction with the environment, while other intracellular processes like the regulation of the protein homeostasis are globally conserved. [ABSTRACT FROM AUTHOR]
- Published
- 2015
- Full Text
- View/download PDF
184. Regulation of Three Nitrogenase Gene Clusters in the Cyanobacterium Anabaena variabilis ATCC 29413.
- Author
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Thiel, Teresa and Pratte, Brenda S.
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- *
NITROGENASES , *CYANOBACTERIA , *ANABAENA variabilis , *HETEROCYSTS , *NITROGEN fixation , *PHOTOSYNTHESIS , *GENE expression - Abstract
The filamentous cyanobacterium Anabaena variabilis ATCC 29413 fixes nitrogen under aerobic conditions in specialized cells called heterocysts that form in response to an environmental deficiency in combined nitrogen. Nitrogen fixation is mediated by the enzyme nitrogenase, which is very sensitive to oxygen. Heterocysts are microxic cells that allow nitrogenase to function in a filament comprised primarily of vegetative cells that produce oxygen by photosynthesis. A. variabilis is unique among well-characterized cyanobacteria in that it has three nitrogenase gene clusters that encode different nitrogenases, which function under different environmental conditions. The nif1 genes encode a Mo-nitrogenase that functions only in heterocysts, even in filaments grown anaerobically. The nif2 genes encode a different Mo-nitrogenase that functions in vegetative cells, but only in filaments grown under anoxic conditions. An alternative V-nitrogenase is encoded by vnf genes that are expressed only in heterocysts in an environment that is deficient in Mo. Thus, these three nitrogenases are expressed differentially in response to environmental conditions. The entire nif1 gene cluster, comprising at least 15 genes, is primarily under the control of the promoter for the first gene, nifB1. Transcriptional control of many of the downstream nif1 genes occurs by a combination of weak promoters within the coding regions of some downstream genes and by RNA processing, which is associated with increased transcript stability. The vnf genes show a similar pattern of transcriptional and post-transcriptional control of expression suggesting that the complex pattern of regulation of the nif1 cluster is conserved in other cyanobacterial nitrogenase gene clusters. [ABSTRACT FROM AUTHOR]
- Published
- 2014
- Full Text
- View/download PDF
185. Erythrocyte-mediated delivery of phenylalanine ammonia lyase for the treatment of phenylketonuria in BTBR-Pahenu2 mice.
- Author
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Rossi, Luigia, Pierigè, Francesca, Carducci, Claudia, Gabucci, Claudia, Pascucci, Tiziana, Canonico, Barbara, Bell, Sean M., Fitzpatrick, Paul A., Leuzzi, Vincenzo, and Magnani, Mauro
- Subjects
- *
ERYTHROCYTES , *PHENYLALANINE ammonia lyase , *PHENYLKETONURIA treatment , *ANABAENA variabilis , *LABORATORY mice - Abstract
Phenylketonuria (PKU) is an autosomal recessive genetic disease caused by defects in the phenylalanine hydroxylase gene. Preclinical and clinical investigations suggest that phenylalanine ammonia lyase (PAL) could be an effective alternative for the treatment of PKU. The aim of this study is to investigate if erythrocytes loaded with PAL may act as a safe delivery system able to overcome bioavailability issues and to provide, in vivo, a therapeutically relevant concentration of enzyme. Murine erythrocytes were loaded with recombinant PAL from Anabaena variabilis (r Av PAL) and their ability to perform as bioreactors was assessed in vivo in adult BTBR-Pah enu2 mice, the genetic murine model of PKU. Three groups of mice were treated with a single i.v. injection of r Av PAL-RBCs at three different doses to select the most appropriate one for assessment of efficacy. Repeated administrations at 9–10 day-intervals of the selected dose for 10 weeks showed that the therapeutic effect was persistent and not affected by the generation of antibodies induced by the recombinant enzyme. This therapeutic approach deserves further in vivo evaluation either as a potential option for the treatment of PKU patients or as a possible model for the substitutive enzymatic treatment of other inherited metabolic disorders. [ABSTRACT FROM AUTHOR]
- Published
- 2014
- Full Text
- View/download PDF
186. Effects of cell density, carbon dioxide and molybdenum concentration on biohydrogen production by Anabaena variabilis ATCC 29413.
- Author
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Salleh, Siti Fatihah, Kamaruddin, Azlina, Uzir, Mohamad Hekarl, and Mohamed, Abdul Rahman
- Subjects
- *
CARBON dioxide , *ANABAENA variabilis , *MOLYBDENUM , *INTERSTITIAL hydrogen generation , *CARBON compounds , *BIOMASS energy - Abstract
This paper aims to determine the effects of cell density, carbon dioxide, and molybdenum concentration towards hydrogen production rate. Batch cultures of Anabaena variabilis sp. were incubated in anaerobic environment under continuous indoor illumination of 70 μE m −2 s −1 at 35 °C. The optimal volumetric hydrogen production rate obtained was 44 μmol H 2 mg chl a − 1 h −1 occurred at cells density of 110 mg L −1 , 5% carbon dioxide headspace concentration, and molybdenum concentration of 1.6 mM. The effect of organic carbon source (glucose) was also evaluated in the present study and it was found that the additional carbon produced the highest hydrogen production rate in all conditions. An increased concentration of molybdenum significantly enhanced the hydrogen productivity rate almost to that of glucose-supplemented culture at 49 μmol H 2 mg chl a − 1 h −1 . However, further increase in molybdenum concentration beyond 1.6 mM showed no further improvement in the amount of hydrogen produced. [ABSTRACT FROM AUTHOR]
- Published
- 2014
- Full Text
- View/download PDF
187. Complete genome sequence of Anabaena variabilis ATCC 29413.
- Author
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Thiel, Teresa, Pratte, Brenda, Zhong, Jinshun, Goodwin, Lynne, Copeland, Alex, Lucas, Susan, Han, Cliff, Pitluck, Sam, Land, Miriam, Kyrpides, Nikos, and Woyke, Tanja
- Subjects
- *
ANABAENA variabilis , *NOSTOCACEAE , *GENOMES , *PHYLOGENY , *NITROGENASES - Abstract
Anabaena variabilis ATCC 29413 is a filamentous, heterocyst-forming cyanobacterium that has served as a model organism, with an extensive literature extending over 40 years. The strain has three distinct nitrogenases that function under different environmental conditions and is capable of photoautotrophic growth in the light and true heterotrophic growth in the dark using fructose as both carbon and energy source. While this strain was first isolated in 1964 in Mississippi and named Anabaena flos-aquae MSU A-37, it clusters phylogenetically with cyanobacteria of the genus Nostoc. The strain is a moderate thermophile, growing well at approximately 40° C. Here we provide some additional characteristics of the strain, and an analysis of the complete genome sequence. [ABSTRACT FROM AUTHOR]
- Published
- 2014
- Full Text
- View/download PDF
188. Nitrogen Fixation in Phototrophic Bacteria
- Author
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Gallon, J. R., Wolk, C. P., Summerfield, R. J., editor, Tikhonovich, Igor A., editor, Provorov, Nikolai A., editor, Romanov, Vassily I., editor, and Newton, William E., editor
- Published
- 1995
- Full Text
- View/download PDF
189. The Formation of Spore-Like Akinetes: A Survival Strategy of Filamentous Cyanobacteria
- Author
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Ritu Garg and Iris Maldener
- Subjects
Cyanobacteria ,Spores, Bacterial ,Akinete ,Anabaena ,Heterocyst ,Stress resistance ,Germination ,Envelope ,biology ,Physiology ,Chemistry ,Cyanophycin ,Nitrogen ,Cell Biology ,biology.organism_classification ,Applied Microbiology and Biotechnology ,Biochemistry ,Microbiology ,Spore ,chemistry.chemical_compound ,Botany ,Anabaena variabilis ,Glycogen ,Biotechnology - Abstract
Some cyanobacteria of the order Nostocales can form akinetes, spore-like dormant cells resistant to various unfavorable environmental fluctuations. Akinetes are larger than vegetative cells and contain large quantities of reserve products, mainly glycogen and the nitrogen storage polypeptide polymer cyanophycin. Akinetes are enveloped in a thick protective coat containing a multilayered structure and are able to germinate into new vegetative cells under suitable growth conditions. Here, we summarize the significant morphological and physiological changes that occur during akinete differentiation and germination and present our investigation of the physiological function of the storage polymer cyanophycin in these cellular processes. We show that the cyanophycin production is not required for formation and germination of the akinetes in the filamentous cyanobacterium Anabaena variabilis ATCC 29413.
- Published
- 2021
190. Overexpression of Flavodoxin in Alfalfa Nodules Leads to Delayed Senescence and High Starch Accumulation
- Author
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de la Peña, T. C., Redondo, F. J., Lucas, M. M., Pueyo, J. J., Dakora, Felix D., editor, Chimphango, Samson B. M., editor, Valentine, Alex J., editor, Elmerich, Claudine, editor, and Newton, William E., editor
- Published
- 2008
- Full Text
- View/download PDF
191. Low-Iron Stress in the Cyanobacterium Anabaena variabilis
- Author
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Michelsen, Birgit, Miller, Mette, Cox, Raymond P., and Baltscheffsky, M., editor
- Published
- 1990
- Full Text
- View/download PDF
192. Regulation of Nitrogenase Gene Expression by Transcript Stability in the Cyanobacterium Anabaena variabilis.
- Author
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Pratte, Brenda S. and Thiel, Teresa
- Subjects
- *
NITROGENASES , *GENE expression , *CYANOBACTERIA , *ANABAENA variabilis , *GENETIC regulation , *BACTERIA - Abstract
The nitrogenase gene cluster in cyanobacteria has been thought to comprise multiple operons; however, in Anabaena variabilis, the promoter for the first gene in the cluster, nifB1, appeared to be the primary promoter for the entire ni/cluster. The structural genes nifHDK1 were the most abundant transcripts; however, their abundance was not controlled by an independent nifH1 promoter, but rather, by RNA processing, which produced a very stable nifH1 transcript and a moderately stable nifD1 transcript. There was also no separate promoter for nifEN1. In addition to the nifB1 promoter, there were weak promoters inside the nifU1 gene and inside the nifE1 gene, and both promoters were heterocyst specific. In an xisA mutant, which effectively separated promoters upstream of an 11-kb excision element in nifD1 from the downstream genes, the internal nifE1 promoter was functional. Transcription of the nif1 genes downstream of the 11-kb element, including the most distant genes, hesAB1 and fdxH1, was reduced in the xisA mutant, indicating that the nifB1 promoter contributed to their expression. However, with the exception of nifK1 and nifE1, which had no expression, the downstream genes showed low to moderate levels of transcription in the xisA mutant. The hesA1 gene also had a promoter, but the fdxH gene had a processing site just upstream of the gene. The processing of transcripts at sites upstream of nifH1 and fdxH1 correlated with increased stability of these transcripts, resulting in greater amounts than transcripts that were not close to processing sites. [ABSTRACT FROM AUTHOR]
- Published
- 2014
- Full Text
- View/download PDF
193. Isolation, improvement and characterization of an ammonium excreting mutant strain of the heterocytous cyanobacterium, Anabaena variabilis PCC 7937.
- Author
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Lan Anh Bui, Dupre, Catherine, Legrand, Jack, and Grizeau, Dominique
- Subjects
- *
AMMONIUM , *NITROGEN fertilizers , *CYANOBACTERIA , *BACTERIAL mutation , *ANABAENA variabilis , *NITROGEN-fixing bacteria - Abstract
Besides potential applications in the agriculture field as natural nitrogen fertilizer, N2-fixing cyanobacteria have recently gained some attentions for new applications linked to the potential production of biologically active molecules or biohydrogen. Ammonium bioproduction is also gaining attention with the potential use of microalgae in biofuels production and the concerns about the increasing needs for nitrogen substrates. This study has investigated some phenotypic traits linked to biomass production and ammonium release in multicellular cyanobacteria, Anabaena variabilis PCC 7937. It confirms that this wild-type strain has no natural ability for ammonium excretion under diazotrophic conditions. A mutant strain, A. variabilis PCC 7937-C9, was obtained after double random mutagenesis treatments with ethyl methane-sulfonate and screening in batch cultures for resistance to the effect of a glutamine synthetase inhibitor, l-methionine-d,l-sulfoximine (MSX). Although significantly characterized by shorter cell filaments, the growth parameters in photobioreactors of the mutant strain cultures were in the same range of values than those of the wild type. In the presence of MSX this strain was shown to produce extracellular ammonium, with specific rates up to 4.9µmol NH4+mgChl a-1h-1. The efficiency of this strain, estimated by its specific rate of ammonium excretion, was shown to be improved after consecutive batch cultures with increasing concentrations of MSX. Such mutant strains are of potential use for investigating ways to improve extracellular ammonium bioproduction. [ABSTRACT FROM AUTHOR]
- Published
- 2014
- Full Text
- View/download PDF
194. Temporal dynamics of ROS biogenesis under simulated solar radiation in the cyanobacterium Anabaena variabilis PCC 7937.
- Author
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Singh, Shailendra, Rastogi, Rajesh, Häder, Donat-P., and Sinha, Rajeshwar
- Subjects
- *
REACTIVE oxygen species , *ANABAENA variabilis , *SOLAR radiation , *WAVELENGTHS , *ANABAENA , *FIBERS - Abstract
We studied the temporal generation of reactive oxygen species (ROS) in the cyanobacterium Anabaena variabilis PCC 7937 under simulated solar radiation using WG 280, WG 295, WG 305, WG 320, WG 335, WG 345, and GG 400 nm cut-off filters to find out the minimum exposure time and most effective region of the solar spectrum inducing highest level of ROS. There was no significant generation of ROS in all treatments in comparison to the samples kept in the dark during the first 8 h of exposure; however, after 12 h of exposure, ROS were significantly generated in samples covered with 305, 295, or 280 nm cut-off filters. In contrast with ROS, the fragmentation of filaments was predominantly seen in 280 nm cut-off filter covered samples after 12 h of exposure. After 24 h of exposure, ROS levels were significantly higher in all samples than in the dark; however, the ROS signals were more pronounced in 320, 305, 295, or 280 nm cut-off filter covered samples. In contrast, the length of filaments was reduced in 305, 295, or 280 nm cut-off filter covered samples after 24 h of exposure. Thus, fragmentation of the filament was induced by all wavelengths of the UV-B region contrary to the UV-A region where only shorter wavelengths were able to induce the fragmentation. In contrast, ROS were generated by all wavelengths of the solar spectrum after 24 h of exposure; however, shorter wavelengths of both the UV-A and the UV-B regions were more effective in generating ROS in comparison to their higher wavelengths and photosynthetic active radiation (PAR). Moreover, lower wavelengths of UV-B were more efficient than the lower wavelengths of the UV-A radiation. Findings from this study suggest that certain threshold levels of ROS are required to induce the fragmentation of filaments. [ABSTRACT FROM AUTHOR]
- Published
- 2014
- Full Text
- View/download PDF
195. Optimized Condition for Enhanced Soluble-Expression of Recombinant Mutant Anabaena Variabilis Phenylalanine Ammonia Lyase.
- Author
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Jaliani, Hossein Zarei, Farajnia, Safar, Safdari, Yaghoub, Mohammadi, Seyyed Abolghasem, Barzegar, Abolfazl, and Talebi, Saeed
- Subjects
- *
ANABAENA variabilis , *PHENYLALANINE ammonia lyase , *RECOMBINANT proteins , *MUTANT proteins , *PHENYLKETONURIA treatment , *GENETIC vectors , *CELL culture - Abstract
Purpose: Recently discovered Anabaena variabilis phenylalanine ammonia lyase (AvPAL) proved to be a good candidate for enzyme replacement therapy of phenylketonuria. Outstanding stability properties of a mutant version of this enzyme, produced already in our laboratory, have led us to the idea of culture conditions optimization for soluble expression of this therapeutically valuable enzyme in E. coli. Methods: In the present study, the gene encoding mutant version of AvPAL was cloned into the pET28a expression vector. Different concentrations of IPTG, induction period, growth temperature, shaking speed, as well as different types of culture media were examined with respect to the amount of recombinant protein produced and specific activity of the enzyme. Results: Based upon our findings, maximum amount of active mutant enzyme was attained by addition of 0.5 mM IPTG at 150 rpm to the TB culture media. The yield of active enzyme at cluture tempreature of 25 °C and induction period of 18 hour was the highest. Conclusion: The results of this study indicated that the yield of mutant AvPAL production in E. coli can be affected mainly by culture temperature and inducer concentration. [ABSTRACT FROM AUTHOR]
- Published
- 2014
- Full Text
- View/download PDF
196. Single-dose, subcutaneous recombinant phenylalanine ammonia lyase conjugated with polyethylene glycol in adult patients with phenylketonuria: an open-label, multicentre, phase 1 dose-escalation trial.
- Author
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Longo, Nicola, Harding, Cary O., Burton, Barbara K., Grange, Dorothy K., Vockley, Jerry, Wasserstein, Melissa, Rice, Gregory M., Dorenbaum, Alejandro, Neuenburg, Jutta K., Musson, Donald G., Zhonghua Gu, and Sile, Saba
- Subjects
- *
PHENYLKETONURIA , *PHENYLALANINE hydroxylase , *TYROSINE , *PHENYLALANINE , *ANABAENA variabilis , *PHENYLALANINE ammonia lyase , *PLANT enzymes , *POLYETHYLENE glycol - Abstract
Phenylketonuria is an inherited disease caused by impaired activity of phenylalanine hydroxylase, the enzyme that converts phenylalanine to tyrosine, leading to accumulation of phenylalanine and subsequent neurocognitive dysfunction. Phenylalanine ammonia lyase is a prokaryotic enzyme that converts phenylalanine to ammonia and trans-cinnamic acid. We aimed to assess the safety, tolerability, pharmacokinetic characteristics, and efficacy of recombinant Anabaena variabilis phenylalanine ammonia lyase (produced in Escherichia coli) conjugated with polyethylene glycol (rAvPAL-PEG) in reducing phenylalanine concentrations in adult patients with phenylketonuria. Methods In this open-label, phase 1, multicentre trial, single subcutaneous injections of rAvPAL-PEG were given in escalating doses (0⋅001, 0⋅003, 0⋅010, 0⋅030, and 0⋅100 mg/kg) to adults with phenylketonuria. Participants aged 18 years or older with blood phenylalanine concentrations of 600 µmol/L or higher were recruited from among patients attending metabolic disease clinics in the USA. The primary endpoints were safety and tolerability of rAvPAL-PEG. Secondary endpoints were the pharmacokinetic characteristics of the drug and its effect on concentrations of phenylalanine. Participants and investigators were not masked to assigned dose group. This study is registered with ClinicalTrials.gov, number NCT00925054. Findings 25 participants were recruited from seven centres between May 6, 2008, and April 15, 2009, with five participants assigned to each escalating dose group. All participants were included in the safety population. The most frequently reported adverse events were injection-site reactions and dizziness, which were self-limited and without sequelae. Two participants had serious adverse reactions to intramuscular medroxyprogesterone acetate, a drug that contains polyethylene glycol as an excipient. Three of five participants given the highest dose of rAvPAL-PEG (0⋅100 mg/kg) developed a generalised skin rash. By the end of the study, all participants had developed antibodies against polyethylene glycol, and some against phenylalanine ammonia lyase as well. Drug concentrations peaked about 89--106 h after administration of the highest dose. Treatment seemed to be effective at reducing blood phenylalanine in all five participants who received the highest dose (mean reduction of 54⋅2% from baseline), with a nadir about 6 days after injection and an inverse correlation between drug and phenylalanine concentrations in plasma. Phenylalanine returned to near-baseline concentrations about 21 days after the injection. Interpretation Subcutaneous administration of rAvPAL-PEG in a single dose of up to 0⋅100 mg/kg was fairly safe and well tolerated in adult patients with phenylketonuria. At the highest dose tested, rAvPAL-PEG reduced blood phenylalanine concentrations. In view of the development of antibodies against polyethylene glycol (and in some cases against phenylalanine ammonia lyase), future studies are needed to assess the effect of repeat dosing. [ABSTRACT FROM AUTHOR]
- Published
- 2014
- Full Text
- View/download PDF
197. Promising microbial consortia for producing biofertilizers for rice fields.
- Author
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Zayadan, B., Matorin, D., Baimakhanova, G., Bolathan, K., Oraz, G., and Sadanov, A.
- Subjects
- *
BIOFERTILIZERS , *PADDY fields , *CYANOBACTERIA , *ANABAENA variabilis , *NOSTOC , *MICROALGAE - Abstract
Two cyanobacterial cultures from rice paddies of Kyzylorda Provence, Kazakhstan were isolated and characterized: Anabaena variabilis and Nostoc calsicola. Based on these cultures, new consortia of cyanobacteria, microalgae and Azotobacter were developed: ZOB-1 ( Anabaena variabilis, Chlorella vulgaris, and Azotobacter sp.) and ZOB-2 ( Nostoc calsicola, Chlorella vulgaris, and Azotobacter sp.). High growth rate and photosynthetic activity of microalgae were observed in these consortia. The active consortium ZOB-1 was selected, which improved germination and growth of rice plants. ZOB-1 was recommended as a biostimulator and biofertilizer for crops. [ABSTRACT FROM AUTHOR]
- Published
- 2014
- Full Text
- View/download PDF
198. Is vanadium a biometal for boreal cyanolichens?
- Author
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Darnajoux, Romain, Constantin, Jérôme, Miadlikowska, Jolanta, Lutzoni, François, and Bellenger, Jean‐Philippe
- Subjects
- *
VANADIUM , *MOLYBDENUM , *NITROGENASES , *NITROGEN fixation , *ANABAENA variabilis , *HOMEOSTASIS - Abstract
Molybdenum (Mo) nitrogenase has long been considered the predominant isoenzyme responsible for dinitrogen fixation worldwide. Recent findings have challenged the paradigm of Mo hegemony, and highlighted the role of alternative nitrogenases, such as the vanadium-nitrogenase., Here, we first characterized homeostasis of vanadium (V) along with other metals in situ in the dinitrogen fixing cyanolichen Peltigera aphthosa. These lichens were sampled in natural sites exposed to various levels of atmospheric metal deposition. These results were compared with laboratory experiments where Anabaena variabilis, which is also hosting the V-nitrogenase, and a relatively close relative of the lichen cyanobiont Nostoc, was subjected to various levels of V., We report here that V is preferentially allocated to cephalodia, specialized structures where dinitrogen fixation occurs in tri-membered lichens. This specific allocation is biologically controlled and tightly regulated. Vanadium homeostasis in lichen cephalodia exposed to various V concentrations is comparable to the one observed in Anabaena variabilis and other dinitrogen fixing organisms using V-nitrogenase., Overall, our findings support current hypotheses that V could be a more important factor in mediating nitrogen input in high latitude ecosystems than previously recognized. They invite the reassessment of current theoretical models linking metal dynamics and dinitrogen fixation in boreal and subarctic ecosystems. [ABSTRACT FROM AUTHOR]
- Published
- 2014
- Full Text
- View/download PDF
199. Algal and cyanobacterial bioenergy and diversity.
- Author
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Eaton-Rye, Julian J., Packer, Michael A., Summerfield, Tina C., and Wood, Susanna A.
- Subjects
- *
CYANOBACTERIA , *BIOMASS energy , *PHOTOSYSTEMS , *HOMEOBOX genes , *HYDROGENASE , *ANABAENA variabilis , *GENETIC mutation - Published
- 2014
- Full Text
- View/download PDF
200. Flux balancing of light and nutrients in a biofilm photobioreactor for maximizing photosynthetic productivity.
- Author
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Murphy, Thomas E. and Berberoglu, Halil
- Subjects
BIOFILMS ,PHOTOBIOREACTORS ,PHOTOSYNTHETIC reaction centers ,PHOTOSYNTHETIC cyanobacteria ,ANABAENA variabilis ,ALGAL growth ,MASS transfer - Abstract
This article reports a combined experimental and numerical study on the efficient operation of Porous Substrate Bioreactors. A comprehensive model integrating light transport, mass transport, and algal growth kinetics was used to understand the productivity of photosynthetic biofilms in response to delivery rates of photons and nutrients. The reactor under consideration was an evaporation driven Porous Substrate Bioreactor (PSBR) cultivating the cyanobacteria Anabaena variabilis as a biofilm on a porous substrate which delivers water and nutrients to the cells. In an unoptimized experimental case, this reactor was operated with a photosynthetic efficiency of 2.3%, competitive with conventional photobioreactors. Moreover, through a scaling analysis, the location at which the phosphate delivery rate decreased the growth rate to half of its uninhibited value was predicted as a function of microorganism and bioreactor properties. The numerical model along with the flux balancing techniques presented herein can serve as tools for designing and selecting operating parameters of biofilm based cultivation systems for maximum productivity. © 2014 American Institute of Chemical Engineers Biotechnol. Prog., 30:348-359, 2014 [ABSTRACT FROM AUTHOR]
- Published
- 2014
- Full Text
- View/download PDF
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