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Wei Xiong, Gaozhong Shen, Donald A Bryant
The genome of the model cyanobacterium, Synechococcus sp. PCC 7002, encodes two paralogs of CruA-type lycopene cyclases, SynPCC7002_A2153 and SynPCC7002_A0043, which are denoted cruA and cruP, respectively. Unlike the wild-type strain, a cruA deletion mutant is light-sensitive, grows slowly, and accumulates lycopene, γ-carotene, and 1-OH-lycopene; however, this strain still produces β-carotene and other carotenoids derived from it. Expression of cruA from Synechocystis sp. PCC 6803 (cruA 6803) in Escherichia coli strains that synthesize either lycopene or γ-carotene did not lead to the synthesis of either γ-carotene or β-carotene, respectively...
October 14, 2016: Photosynthesis Research
Bradley W Abramson, Benjamin Kachel, David M Kramer, Daniel C Ducat
In plants, a limited capacity to utilize or export the end products of the Calvin Benson cycle (CB) from photosynthetically-active source cells to non-photosynthetic sink cells can result in reduced carbon capture, photosynthetic electron transport (PET) and lowered photochemical efficiency. The downregulation of photosynthesis caused by reduced capacity to utilize photosynthate has been termed "sink limitation". Recently, several cyanobacterial and algal strains engineered to over-produce target metabolites have exhibited increased photochemistry suggesting possible source-sink regulatory mechanisms may be involved...
October 13, 2016: Plant & Cell Physiology
Kazuyoshi Murata, Sayuri Hagiwara, Yoshitaka Kimori, Yasuko Kaneko
Some cyanobacteria exhibit compaction of DNA in synchrony with their circadian rhythms accompanying cell division. Since the structure is transient, it has not yet been described in detail. Here, we successfully visualize the ultrastructure of compacted DNA in the cyanobacterium Synechococcus elongatus PCC 7942 under rigorous synchronized cultivation by means of high-voltage cryo-electron tomography. In 3D reconstructions of rapidly frozen cells, the compacted DNA appears as an undulating rod resembling a eukaryotic condensed chromosome...
October 12, 2016: Scientific Reports
Sachia J Traving, Mikkel Bentzon-Tilia, Helle Knudsen-Leerbeck, Mustafa Mantikci, Jørgen L S Hansen, Colin A Stedmon, Helle Sørensen, Stiig Markager, Lasse Riemann
Bacterioplankton play a key role in marine waters facilitating processes important for carbon cycling. However, the influence of specific bacterial populations and environmental conditions on bacterioplankton community performance remains unclear. The aim of the present study was to identify drivers of bacterioplankton community functions, taking into account the variability in community composition and environmental conditions over seasons, in two contrasting coastal systems. A Least Absolute Shrinkage and Selection Operator (LASSO) analysis of the biological and chemical data obtained from surface waters over a full year indicated that specific bacterial populations were linked to measured functions...
2016: Frontiers in Microbiology
David J Lea-Smith, Maite L Ortiz-Suarez, Tchern Lenn, Dennis J Nurnberg, Laura L Baers, Matthew P Davey, Lucia Parolini, Roland G Huber, Charles A R Cotton, Giulia Mastroianni, Paolo Bombelli, Petra Ungerer, Tim J Stevens, Alison G Smith, Peter J Bond, Conrad W Mullineaux, Christopher J Howe
Cyanobacteria are intricately organized, incorporating an array of internal thylakoid membranes, the site of photosynthesis, into cells no larger than other bacteria. They also synthesize C15-C19 alkanes and alkenes, which results in substantial production of hydrocarbons in the environment. All sequenced cyanobacteria encode hydrocarbon biosynthesis pathways, suggesting an important, undefined physiological role for these compounds. Here we demonstrate that hydrocarbon deficient mutants of Synechococcus sp...
October 5, 2016: Plant Physiology
Kouji Kojima, Sumie Keta, Kazuma Uesaka, Akihiro Kato, Nobuyuki Takatani, Kunio Ihara, Tatsuo Omata, Makiko Aichi
Cyanobacterial mutants defective in acyl-acyl carrier protein synthetase (Aas) secrete free fatty acids (FFAs) into the external medium and hence have been used for the studies aimed at photosynthetic production of biofuels. While the wild-type strain of Synechocystis sp. PCC 6803 is highly sensitive to exogenously added linolenic acid, mutants defective in the aas gene are known to be resistant to the externally provided fatty acid. In this study, the wild-type Synechocystis cells were shown to be sensitive to lauric, oleic, and linoleic acids as well, and the resistance to these fatty acids was shown to be enhanced by inactivation of the aas gene...
October 4, 2016: Applied Microbiology and Biotechnology
Marcia F Marston, Jennifer B H Martiny
Understanding the structure and origin of natural bacteriophage genomic diversity is important in elucidating how bacteriophages influence the mortality rates and composition of their host communities. Here we examine the genetic structure and genomic diversification of naturally occurring bacteriophages by analyzing the full genomic sequences of over 100 isolates of Synechococcus-infecting cyanophages collected over 15 years from coastal waters of Southern New England, USA. Our analysis revealed well-supported cyanophage genomic clusters (genome-wide average nucleotide identity (ANI) >93%) and subclusters (genome-wide ANI >98%) that remained consistent for a decade or longer...
October 1, 2016: Environmental Microbiology
Hung Li, Claire R Shen, Chun-Hung Huang, Li-Yu Sung, Meng-Ying Wu, Yu-Chen Hu
Cyanobacteria hold promise as a cell factory for producing biofuels and bio-derived chemicals, but genome engineering of cyanobacteria such as Synechococcus elongatus PCC 7942 poses challenges because of their oligoploidy nature and long-term instability of the introduced gene. CRISPR-Cas9 is a newly developed RNA-guided genome editing system, yet its application for cyanobacteria engineering has yet to be reported. Here we demonstrated that CRISPR-Cas9 system can effectively trigger programmable double strand break (DSB) at the chromosome of PCC 7942 and provoke cell death...
September 27, 2016: Metabolic Engineering
Daniel C O Thornton, Jie Chen
Exopolymer particles are found throughout the ocean and play a significant biogeochemical role in carbon cycling. Transparent exopolymer particles (TEP) are composed of acid polysaccharides and Coomassie staining particles (CSP) are proteins. TEP have been extensively studied in the ocean, while CSP have been largely overlooked. The objective of this research was to determine the role of stress and cell permeability in the formation of TEP and CSP. The diatom Thalassiosira weissflogii and cyanobacterium Synechococcus elongatus were grown in batch cultures and exposed to hydrogen peroxide (0, 10, and 100 μM) as an environmental stressor...
September 30, 2016: Journal of Phycology
Sun Young Choi, Hyun Jeong Lee, Jaeyeon Choi, Jiye Kim, Sang Jun Sim, Youngsoon Um, Yunje Kim, Taek Soon Lee, Jay D Keasling, Han Min Woo
BACKGROUND: Metabolic engineering of cyanobacteria has enabled photosynthetic conversion of CO2 to value-added chemicals as bio-solar cell factories. However, the production levels of isoprenoids in engineered cyanobacteria were quite low, compared to other microbial hosts. Therefore, modular optimization of multiple gene expressions for metabolic engineering of cyanobacteria is required for the production of farnesyl diphosphate-derived isoprenoids from CO2. RESULTS: Here, we engineered Synechococcus elongatus PCC 7942 with modular metabolic pathways consisting of the methylerythritol phosphate pathway enzymes and the amorphadiene synthase for production of amorpha-4,11-diene, resulting in significantly increased levels (23-fold) of amorpha-4,11-diene (19...
2016: Biotechnology for Biofuels
Kanchariya Phankhajon, Anchana Somdee, Theerasak Somdee
An actinomycete strain (KKU-A3) with algicidal activity against Microcystis aeruginosa was isolated from soil in Khon Kaen Province, Thailand. Based on its phenotypic characteristics and 16S rDNA sequence, strain KKU-A3 was identified as Streptomyces rameus. Strain KKU-A3 also exhibited algicidal activity against the cyanobacteria Synechococcus elongatus, Cylindrospermum sp. and Oscillatoria sp. A mathematical and statistical technique was used to optimize the culture conditions and maximize its anti-Microcystis activity...
September 2016: Water Science and Technology: a Journal of the International Association on Water Pollution Research
Roshni Joy Best, Jan J Lyczakowski, Sara Abalde-Cela, Ziyi Yu, Chris Abell, Alison G Smith
Microalgae and cyanobacteria are promising organisms for sustainable biofuel production, but several challenges remain to make this economically viable, including identification of optimised strains with high biomass productivity. Here we report on a novel methodology for the label-free screening and sorting of cyanobacteria and microalgae in a microdroplet platform. We show for the first time that chlorophyll fluorescence can be used to measure differences in biomass between populations of droplets containing different species of cyanobacteria, Synechocystis PCC 6803 and Synechococcus PCC 7002, which exhibit different growth dynamics in bulk culture...
September 28, 2016: Analytical Chemistry
Xiaomin Xia, Frédéric Partensky, Laurence Garczarek, Koji Suzuki, Cui Guo, Shun Yan Cheung, Hongbin Liu
The widespread unicellular cyanobacteria Synechococcus are major contributors to global marine primary production. Here we report their abundance, phylogenetic diversity (as assessed using the RNA polymerase gamma subunit gene rpoC1) and pigment diversity (as indirectly assessed using the laterally transferred cpeBA genes, encoding phycoerythrin-I) in surface waters of the northwestern Pacific Ocean, sampled over nine distinct cruises (2008-2015). Abundance of Synechococcus was low in the subarctic ocean and South China Sea, intermediate in the western subtropical Pacific Ocean, and the highest in the Japan and East China seas...
September 26, 2016: Environmental Microbiology
Hong-Li Hua, Fa-Zhan Zhang, Abraham Alemayehu Labena, Chuan Dong, Yan-Ting Jin, Feng-Biao Guo
Investigation of essential genes is significant to comprehend the minimal gene sets of cell and discover potential drug targets. In this study, a novel approach based on multiple homology mapping and machine learning method was introduced to predict essential genes. We focused on 25 bacteria which have characterized essential genes. The predictions yielded the highest area under receiver operating characteristic (ROC) curve (AUC) of 0.9716 through tenfold cross-validation test. Proper features were utilized to construct models to make predictions in distantly related bacteria...
2016: BioMed Research International
Maxime Bourrelle-Langlois, Geneviève Morrow, Stéphanie Finet, Robert M Tanguay
We previously reported the in silico characterization of Synechococcus sp. phage 18 kDa small heat shock protein (HspSP-ShM2). This small heat shock protein (sHSP) contains a highly conserved core alpha crystalline domain of 92 amino acids and relatively short N- and C-terminal arms, the later containing the classical C-terminal anchoring module motif (L-X-I/L/V). Here we establish the oligomeric profile of HspSP-ShM2 and its structural dynamics under in vitro experimental conditions using size exclusion chromatography (SEC/FPLC), gradient native gels electrophoresis and dynamic light scattering (DLS)...
2016: PloS One
Masahiro Kanno, Shota Atsumi
Cyanobacteria have attracted much attention as a means to directly recycle carbon dioxide into valuable chemicals that are currently produced from petroleum. However, the titers and productivities achieved are still far below the level required in industry. To make a more industrially applicable production scheme, glycerol, a byproduct of biodiesel production, can be used as an additional carbon source for photomixotrophic chemical production. Glycerol is an ideal candidate due to its availability and low-cost...
September 19, 2016: ACS Synthetic Biology
Ming-Yang Ho, Fei Gan, Gaozhong Shen, Chi Zhao, Donald A Bryant
Far-red light photoacclimation (FaRLiP) is a mechanism that allows some cyanobacteria to utilize far-red light (FRL) for oxygenic photosynthesis. During FaRLiP, cyanobacteria remodel photosystem (PS) I, PS II, and phycobilisomes while synthesizing Chl d, Chl f, and far-red-absorbing phycobiliproteins, and these changes enable these organisms to use FRL for growth. In this study, a conjugation-based genetic system was developed for Synechococcus sp. PCC 7335. Three antibiotic cassettes were successfully used to generate knockout mutations in genes in Synechococcus sp...
September 16, 2016: Photosynthesis Research
Carlos Eduardo De Farias Silva, Eleonora Sforza, Alberto Bertucco
Synechococcus PCC 7002 is an interesting species in view of industrial production of carbohydrates. The cultivation performances of this species are strongly affected by the pH of the medium, which also influences the carbohydrate accumulation. In this work, different methods of pH control were analyzed, in order to obtain a higher production of both Synechococcus biomass and carbohydrates. To better understand the influence of pH on growth and carbohydrate productivity, manual and automatic pH regulation in CO2 and bicarbonate system were applied...
September 13, 2016: Applied Biochemistry and Biotechnology
Ming-Yang Ho, Fei Gan, Gaozhong Shen, Donald A Bryant
Phycobilisomes (PBS) are antenna complexes that harvest light for photosystem (PS) I and PS II in cyanobacteria and some algae. A process known as far-red light photoacclimation (FaRLiP) occurs when some cyanobacteria are grown in far-red light (FRL). They synthesize chlorophylls d and f and remodel PS I, PS II, and PBS using subunits paralogous to those produced in white light. The FaRLiP strain, Leptolyngbya sp. JSC-1, replaces hemidiscoidal PBS with pentacylindrical cores, which are produced when cells are grown in red or white light, with PBS with bicylindrical cores when cells are grown in FRL...
September 13, 2016: Photosynthesis Research
Ginga Shimakawa, Keiichiro Shaku, Chikahiro Miyake
The photoinhibition of photosystem I (PSI) is lethal to oxygenic phototrophs. Nevertheless, it is unclear how photo-damage occurs or how oxygenic phototrophs prevent it. Here, we provide evidence that keeping P700 (the reaction center chlorophyll in PSI) oxidized protects PSI. Previous studies have suggested that PSI photoinhibition does not occur in the two model cyanobacteria, Synechocystis sp. PCC 6803 (S. 6803) and Synechococcus elongatus PCC 7942 (S. 7942), when photosynthetic CO2 fixation was suppressed under low CO2 partial pressure even in mutants deficient in flavodiiron protein (FLV), which mediates alternative electron flow (AEF)...
September 9, 2016: Plant Physiology
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