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https://www.readbyqxmd.com/read/28213307/enhanced-toxicity-to-the-cyanobacterium-microcystis-aeruginosa-by-low-dosage-repeated-exposure-to-the-allelochemical-n-phenyl-1-naphthylamine
#1
Y N Gao, F J Ge, L P Zhang, Y He, Z Y Lu, Y Y Zhang, B Y Liu, Q H Zhou, Z B Wu
It has been puzzling whether and how a plant could exert a strong allelopathic inhibition to the target organisms by releasing low concentrations of allelochemicals. Plant allelochemicals have been proposed to be released continuously, however, direct evidence from specific allelochemicals is urgently required. In the present study, the toxicity of allelochemical N-phenyl-1-naphthylamine (NPN) towards the cyanobacterium Microcystis aeruginosa by two different exposure patterns was compared. One was low-dosage repeated exposure (LRE), in which 50  μg L(-1) NPN was repeatedly dosed to simulate the continual release of allelochemicals, and the other one was high-dosage single exposure (HSE) as per the routine toxicity assay...
January 21, 2017: Chemosphere
https://www.readbyqxmd.com/read/28213141/thermostability-of-photosystem-i-trimers-and-monomers-from-the-cyanobacterium-thermosynechococcus-elongatus
#2
Vladimir V Shubin, Irina V Terekhova, Yulia V Bolychevtseva, Eithar El-Mohsnawy, Matthias Rögner, Werner Mäntele, Marta J Kopczak, Enela Džafić
The performance of solar energy conversion into alternative energy sources in artificial systems highly depends on the thermostability of photosystem I (PSI) complexes Terasaki et al. (2007), Iwuchukwu et al. (2010), Kothe et al. (2013) . To assess the thermostability of PSI complexes from the thermophilic cyanobacterium Thermosynechococcus elongatus heating induced perturbations on the level of secondary structure of the proteins were studied. Changes were monitored by Fourier transform infrared (FT-IR) spectra in the mid-IR region upon slow heating (1°C per minute) of samples in D2O phosphate buffer (pD 7...
February 6, 2017: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
https://www.readbyqxmd.com/read/28211005/resequencing-and-annotation-of-the-nostoc-punctiforme-attc-29133-genome-facilitating-biofuel-and-high-value-chemical-production
#3
Luis E Moraes, Matthew J Blow, Erik R Hawley, Hailan Piao, Rita Kuo, Jennifer Chiniquy, Nicole Shapiro, Tanja Woyke, James G Fadel, Matthias Hess
Cyanobacteria have the potential to produce bulk and fine chemicals and members belonging to Nostoc sp. have received particular attention due to their relatively fast growth rate and the relative ease with which they can be harvested. Nostoc punctiforme is an aerobic, motile, Gram-negative, filamentous cyanobacterium that has been studied intensively to enhance our understanding of microbial carbon and nitrogen fixation. The genome of the type strain N. punctiforme ATCC 29133 was sequenced in 2001 and the scientific community has used these genome data extensively since then...
December 2017: AMB Express
https://www.readbyqxmd.com/read/28210833/energy-transfer-in-anabaena-variabilis-filaments-adapted-to-nitrogen-depleted-and-nitrogen-enriched-conditions-studied-by-time-resolved-fluorescence
#4
Aya Onishi, Shimpei Aikawa, Akihiko Kondo, Seiji Akimoto
Nitrogen is among the most important nutritious elements for photosynthetic organisms such as plants, algae, and cyanobacteria. Therefore, nitrogen depletion severely compromises the growth, development, and photosynthesis of these organisms. To preserve their integrity under nitrogen-depleted conditions, filamentous nitrogen-fixing cyanobacteria reduce atmospheric nitrogen to ammonia, and self-adapt by regulating their light-harvesting and excitation energy-transfer processes. To investigate the changes in the primary processes of photosynthesis, we measured the steady-state absorption and fluorescence spectra and time-resolved fluorescence spectra (TRFS) of whole filaments of the nitrogen-fixing cyanobacterium Anabaena variabilis at 77 K...
February 16, 2017: Photosynthesis Research
https://www.readbyqxmd.com/read/28209814/draft-genome-sequence-of-the-axenic-strain-phormidesmispriestleyi-ulc007-a-cyanobacterium-isolated-from-lake-bruehwiler-larsemann-hills-antarctica
#5
Yannick Lara, Benoit Durieu, Luc Cornet, Olivier Verlaine, Rosmarie Rippka, Igor S Pessi, Agnieszka Misztak, Bernard Joris, Emmanuelle J Javaux, Denis Baurain, Annick Wilmotte
Phormidesmis priestleyi ULC007 is an Antarctic freshwater cyanobacterium. Its draft genome is 5,684,389 bp long. It contains a total of 5,604 protein-encoding genes, of which 22.2% have no clear homologues in known genomes. To date, this draft genome is the first one ever determined for an axenic cyanobacterium from Antarctica.
February 16, 2017: Genome Announcements
https://www.readbyqxmd.com/read/28202362/effects-of-crude-extracts-of-a-saxitoxin-producer-strain-of-the-cyanobacterium-cylindrospermopsis-raciborskii-on-the-swimming-behavior-of-wild-and-laboratory-reared-guppy-poecilia-vivipara
#6
Karina C Lopes, Aloysio da S Ferrão-Filho, Everton G N Dos Santos, Rodolfo A Cunha, Cláudia P Santos
The cyanobacterium Cylindrospermopsis raciborskii is an invasive species in water supply reservoirs worldwide, which can produces cylindrospermopsins and saxitoxins. In the wild, guppy (Poecilia vivipara) can be exposed to cyanotoxins, but those born and reared in laboratory are free of this contact. The aim of this paper was to comparatively measure the locomotor activity of 'wild' and 'lab' P. vivipara before and after exposure to crude extracts of two different cultures of C. raciborskii (CYRF-01), a saxitoxin-procucer strain...
February 12, 2017: Toxicon: Official Journal of the International Society on Toxinology
https://www.readbyqxmd.com/read/28188780/structural-insights-into-the-cold-adaptation-of-the-photosynthetic-pigment-protein-c-phycocyanin-from-an-arctic-cyanobacterium
#7
Hai-Nan Su, Qian-Min Wang, Chun-Yang Li, Kang Li, Wei Luo, Bo Chen, Xi-Ying Zhang, Qi-Long Qin, Bai-Cheng Zhou, Xiu-Lan Chen, Yu-Zhong Zhang, Bin-Bin Xie
The cold adaptation mechanism of phycobiliproteins, the major photosynthetic pigment-proteins in cyanobacteria and red algae, has rarely been studied. Here we reported the biochemical, structural, and molecular dynamics simulation study of the C-phycocyanin from Arctic cyanobacterial strain Pseudanabaena sp. LW0831. We characterized the phycobilisome components of LW0831 and obtained their gene sequences. Compared to the mesophilic counterpart from Arthrospira platensis (Ar-C-PC), LW0831 C-phycocyanin (Ps-C-PC) has a decreased thermostability (∆Tm of -16°C), one of the typical features of cold-adapted enzymes...
February 7, 2017: Biochimica et Biophysica Acta
https://www.readbyqxmd.com/read/28182317/impact-of-light-intensity-and-quality-on-chromatophore-and-nuclear-gene-expression-in-paulinella-chromatophora-an-amoeba-with-nascent-photosynthetic-organelles
#8
Ru Zhang, Eva C M Nowack, Dana C Price, Debashish Bhattacharya, Arthur R Grossman
Plastid evolution has been attributed to a single primary endosymbiotic event that occurred ~1.6 BYA in which a cyanobacterium was engulfed and retained by a eukaryotic cell, although early steps in plastid integration are poorly understood. The photosynthetic amoeba Paulinella chromatophora represents a unique model to study plastid evolution because it contains cyanobacterium-derived photosynthetic organelles termed "chromatophores" that originated relatively recently (0.06-0.14 BYA). The chromatophore genome is ~1/3 the size of the genome of closely related cyanobacteria, but 10-fold larger than most plastid genomes...
February 9, 2017: Plant Journal: for Cell and Molecular Biology
https://www.readbyqxmd.com/read/28174568/co-expression-of-cyanobacterial-genes-for-arsenic-methylation-and-demethylation-in-escherichia-coli-offers-insights-into-arsenic-resistance
#9
Yu Yan, Xi-Mei Xue, Yu-Qing Guo, Yong-Guan Zhu, Jun Ye
Arsenite [As(III)] and methylarsenite [MAs(III)] are the most toxic inorganic and methylated arsenicals, respectively. As(III) and MAs(III) can be interconverted in the unicellular cyanobacterium Nostoc sp. PCC 7120 (Nostoc), which has both the arsM gene (NsarsM), which is responsible for arsenic methylation, and the arsI gene (NsarsI), which is responsible for MAs(III) demethylation. It is not clear how the cells prevent a futile cycle of methylation and demethylation. To investigate the relationship between arsenic methylation and demethylation, we constructed strains of Escherichia coli AW3110 (ΔarsRBC) expressing NsarsM or/and NsarsI...
2017: Frontiers in Microbiology
https://www.readbyqxmd.com/read/28171752/endosymbiosis-did-plastids-evolve-from-a-freshwater-cyanobacterium
#10
Jan de Vries, John M Archibald
Photosynthetic eukaryotes are the product of an endosymbiotic event between a eukaryotic host and a cyanobacterium that became today's plastid. A new phylogenomic study suggests that the closest relative of plastids among extant cyanobacteria is the recently discovered freshwater-dwelling Gloeomargarita lithophora.
February 6, 2017: Current Biology: CB
https://www.readbyqxmd.com/read/28168118/the-embryonic-life-history-of-the-tropical-sea-hare-stylocheilus-striatus-gastropoda-opisthobranchia-under-ambient-and-elevated-ocean-temperatures
#11
Rael Horwitz, Matthew D Jackson, Suzanne C Mills
Ocean warming represents a major threat to marine biota worldwide, and forecasting ecological ramifications is a high priority as atmospheric carbon dioxide (CO2) emissions continue to rise. Fitness of marine species relies critically on early developmental and reproductive stages, but their sensitivity to environmental stressors may be a bottleneck in future warming oceans. The present study focuses on the tropical sea hare, Stylocheilus striatus (Gastropoda: Opisthobranchia), a common species found throughout the Indo-West Pacific and Atlantic Oceans...
2017: PeerJ
https://www.readbyqxmd.com/read/28166438/supplementation-of-spirulina-arthrospira-platensis-improves-lifespan-and-locomotor-activity-in-paraquat-sensitive-dj-1%C3%AE-%C3%AE-93-flies-a-parkinson-s-disease-model-in-drosophila-melanogaster
#12
Ajay Kumar, Pearl K Christian, Komal Panchal, B R Guruprasad, Anand K Tiwari
Spirulina (Arthrospira platensis) is a cyanobacterium (blue-green alga) consumed by humans and other animals because of its nutritional values and pharmacological properties. Apart from high protein contents, it also contains high levels of antioxidant and anti-inflammatory compounds, such as carotenoids, β-carotene, phycocyanin, and phycocyanobilin, indicating its possible pharmaco-therapeutic utility. In the present study using DJ-1β(Δ93) flies, a Parkinson's disease model in Drosophila, we have demonstrated the therapeutic effect of spirulina and its active component C-phycocyanin (C-PC) in the improvement of lifespan and locomotor behavior...
February 6, 2017: Journal of Dietary Supplements
https://www.readbyqxmd.com/read/28165619/modulation-of-fatty-acids-and-hydrocarbons-in-anabaena-7120-and-its-ntca-mutant-under-calcium
#13
Savita Singh, Ekta Verma, Balkrishna Tiwari, Niveshika, Arun Kumar Mishra
Calcium being a signaling molecule and mediator of cell response, we examined the modulation in fatty acid and hydrocarbon profiles of wild type cyanobacterium Anabaena sp. PCC 7120 and its ntcA mutant under the influence of different calcium chloride concentrations (0-10 mM). Dynamic modifications in fatty acid and hydrocarbon profile were evident through GC-FID analysis of extracted lipids. In the wild type, increase in CaCl2 (10 mM) resulted in unsaturation of fatty acids (observed in terms of high MUFA/PUFA ratio) while hydrocarbon production was distinctly high in the mutant strain compared to wild type at all tested concentrations...
February 2017: Journal of Basic Microbiology
https://www.readbyqxmd.com/read/28160048/alcohol-dehydrogenase-adha-plays-a-role-in-ethanol-tolerance-in-model-cyanobacterium-synechocystis-sp-pcc-6803
#14
Rebeca Vidal
The protein AdhA from the cyanobacterium Synechocystis sp. PCC 6803 (hereafter Synechocystis) has been previously reported to show alcohol dehydrogenase activity towards ethanol and both NAD and NADP. This protein is currently being used in genetically modified strains of Synechocystis capable of synthesizing ethanol showing the highest ethanol productivities. In the present work, mutant strains of Synechocystis lacking AdhA have been constructed and tested for tolerance to ethanol. The lack of AdhA in the wild-type strain reduces survival to externally added ethanol at lethal concentration of 4% (v/v)...
February 3, 2017: Applied Microbiology and Biotechnology
https://www.readbyqxmd.com/read/28159891/an-amidase-is-required-for-proper-intercellular-communication-in-the-filamentous-cyanobacterium-anabaena-sp-pcc-7120
#15
Zhenggao Zheng, Amin Omairi-Nasser, Xiying Li, Chunxia Dong, Yan Lin, Robert Haselkorn, Jindong Zhao
Channels that cross cell walls and connect the cytoplasm of neighboring cells in multicellular cyanobacteria are pivotal for intercellular communication. We find that the product of the gene all1140 of the filamentous cyanobacterium Anabaena sp. PCC 7120 is required for proper channel formation. All1140 encodes an amidase that hydrolyses purified peptidoglycans. An All1140-GFP fusion protein is located at the Z-ring in the periplasmic space during most of the cell cycle. An all1140-null mutant (M40) was unable to grow diazotrophically, and no mature heterocysts were observed in the absence of combined nitrogen...
February 3, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/28159708/novel-molecular-insights-into-the-function-and-the-antioxidative-stress-response-of-a-peroxiredoxin-q-protein-from-cyanobacteria
#16
Vijay Tailor, Anand Ballal
The PeroxiredoxinQ (PrxQ) proteins are thiol-based peroxidases that are important for maintaining redox homeostasis in several organisms. Activity of PrxQs is mediated by two cysteines, peroxidatic (Cp) and resolving (Cr), in association with a reducing partner. A PrxQ, Alr3183, from the cyanobacterium, Anabaena PCC 7120, was characterized in this study. Alr3183, which required thioredoxin A (TrxA) for peroxidase activity, was an intramolecular disulfide bond-containing monomeric protein. However, Alr3183 lacking Cp (Alr3183C46S) or Cr (Alr3183C51S) formed intermolecular disulphide linkages and was dimeric...
January 31, 2017: Free Radical Biology & Medicine
https://www.readbyqxmd.com/read/28153019/the-effect-of-enhanced-acetate-influx-on-synechocystis-sp-pcc-6803-metabolism
#17
Kati Thiel, Eerika Vuorio, Eva-Mari Aro, Pauli Tapio Kallio
BACKGROUND: Acetate is a common microbial fermentative end-product, which can potentially be used as a supplementary carbon source to enhance the output of biotechnological production systems. This study focuses on the acetate metabolism of the photosynthetic cyanobacterium Synechocystis sp. PCC 6803 which is unable to grow on acetate as a sole carbon source but still can assimilate it via acetyl-CoA-derived metabolic intermediates. In order to gain insight into the acetate uptake, associated limitations and metabolic effects, a heterologous acetate transporter ActP from Escherichia coli was introduced into Synechocystis to facilitate the transport of supplemented acetate from the medium into the cell...
February 2, 2017: Microbial Cell Factories
https://www.readbyqxmd.com/read/28150026/peroxide-reduction-by-a-metal-dependent-catalase-in-nostoc-punctiforme-cyanobacteria
#18
L Hudek, A A J Torriero, A A Michalczyk, B A Neilan, M L Ackland, Lambert Bräu
This study investigated the role of a novel metal-dependent catalase (Npun_R4582) that reduces hydrogen peroxide in the cyanobacterium Nostoc punctiforme. Quantitative real-time PCR showed that npun_R4582 relative mRNA levels were upregulated by over 16-fold in cells treated with either 2 μM added Co, 0.5 μM added Cu, 500 μM Mn, 1 μM Ni, or 18 μM Zn. For cells treated with 60 μM H2O2, no significant alteration in Npun_R4582 relative mRNA levels was detected, while in cells treated with Co, Cu, Mn, Ni, or Zn and 60 μM peroxide, relative mRNA levels were generally above control or peroxide only treated cells...
February 2, 2017: Applied Microbiology and Biotechnology
https://www.readbyqxmd.com/read/28145721/isolation-and-total-synthesis-of-hoshinolactam-an-antitrypanosomal-lactam-from-a-marine-cyanobacterium
#19
Hidetoshi Ogawa, Arihiro Iwasaki, Shimpei Sumimoto, Masato Iwatsuki, Aki Ishiyama, Rei Hokari, Kazuhiko Otoguro, Satoshi O Mura, Kiyotake Suenaga
In the search for new antiprotozoal substances, hoshinolactam, an antitrypanosomal lactam, was isolated from a marine cyanobacterium. The gross structure was elucidated by spectroscopic analyses, and the absolute configuration was determined by the first total synthesis. Hoshinolactam showed potent antitrypanosomal activity with an IC50 value of 3.9 nM without cytotoxicity against human fetal lung fibroblast MRC-5 cells (IC50 > 25 μM).
February 1, 2017: Organic Letters
https://www.readbyqxmd.com/read/28139350/overexpression-of-endogenous-1-deoxy-d-xylulose-5-phosphate-synthase-dxs-in-cyanobacterium-synechocystis-sp-pcc6803-accelerates-protein-aggregation
#20
Kai Kudoh, Shingo Hotta, Midori Sekine, Rintaro Fujii, Arisu Uchida, Genma Kubota, Yusuke Kawano, Masaki Ihara
1-Deoxy-d-xylulose 5-phosphate synthase (DXS) is a rate-limiting enzyme in the 2-C-methyl-d-erythritol 4-phosphate (MEP) pathway, which is responsible for the production of precursors of all isoprenoids. In a previous study, we had examined the overexpression of an endogenous DXS in a Synechocystis sp. PCC6803 mutant (DXS_ox), and found that the dxs mRNA level was 4-fold higher than that in the wild-type (WT) strain. However, the DXS protein level was only 1.5-fold higher, leading to the assumption that the level might be regulated by post-transcriptional events...
January 27, 2017: Journal of Bioscience and Bioengineering
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