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Yongguang Jiang, Peng Xiao, Yang Liu, Jiangxin Wang, Renhui Li
Cyanobacterial blooms in eutrophic lakes are severe environmental problems worldwide. To characterize the spatiotemporal heterogeneity of cyanobacterial blooms, a high-throughput method is necessary for the specific detection of cyanobacteria. In this study, the cyanobacterial composition of three eutrophic waters in China (Taihu Lake, Dongqian Lake, and Dongzhen Reservoir) was determined by pyrosequencing the cpcBA intergenic spacer (cpcBA-IGS) of cyanobacteria. A total of 2585 OTUs were obtained from the normalized cpcBA-IGS sequence dataset at a distance of 0...
April 2017: Harmful Algae
Xiao-Yu Zheng, Erin K O'Shea
The cyanobacterium Synechococcus elongatus PCC 7942 has multiple copies of its single chromosome, and the copy number varies in individual cells, providing an ideal system to study the effect of genome copy-number variation on cell size and gene expression. Using single-cell fluorescence imaging, we found that protein concentration remained constant across individual cells regardless of genome copy number. Cell volume and the total protein amount from a single gene were both positively, linearly correlated with genome copy number, suggesting that changes in cell volume play an important role in buffering genome copy-number variance...
April 18, 2017: Cell Reports
Cecilio Valadez-Cano, Roberto Olivares-Hernández, Osbaldo Resendis-Antonio, Alexander DeLuna, Luis Delaye
BACKGROUND: Genome degradation of host-restricted mutualistic endosymbionts has been attributed to inactivating mutations and genetic drift while genes coding for host-relevant functions are conserved by purifying selection. Unlike their free-living relatives, the metabolism of mutualistic endosymbionts and endosymbiont-originated organelles is specialized in the production of metabolites which are released to the host. This specialization suggests that natural selection crafted these metabolic adaptations...
April 14, 2017: BMC Evolutionary Biology
Han Min Woo, Hyun Jeong Lee
Metabolic engineering of cyanobacteria has received attention as a sustainable strategy to convert carbon dioxide to various biochemicals including fatty acid-derived biodiesel. Recently, Synechococcus elongatus PCC 7942, a model cyanobacterium, has been engineered to convert CO2 to fatty acid ethyl esters (FAEEs) as biodiesel. Modular pathway has been constructed for FAEE production. Several metabolic engineering strategies were discussed to improve the production levels of FAEEs, including host engineering by improving CO2 fixation rate and photosynthetic efficiency...
April 12, 2017: FEMS Microbiology Letters
E D Swanner, T Bayer, W Wu, L Hao, M Obst, A Sundman, J M Byrne, F M Michel, I C Kleinhanns, A Kappler, R Schoenberg
In this study, we couple iron isotope analysis to microscopic and mineralogical investigation of iron speciation during circumneutral Fe(II) oxidation and Fe(III) precipitation with photosynthetically produced oxygen. In the presence of the cyanobacterium Synechococcus PCC 7002, aqueous Fe(II) (Fe(II)aq) is oxidized and precipitated as amorphous Fe(III) oxyhydroxide minerals (iron precipitates, Feppt), with distinct isotopic fractionation (ε(56)Fe) values determined from fitting the δ(56)Fe(II)aq (1.79‰ and 2...
April 21, 2017: Environmental Science & Technology
Sayuri Arai, Kayoko Hayashihara, Yuki Kanamoto, Kazunori Shimizu, Yasutaka Hirokawa, Taizo Hanai, Akio Murakami, Hiroyuki Honda
Enhancement of alcohol tolerance in microorganisms is an important strategy for improving bioalcohol productivity. Although cyanobacteria can be used as a promising biocatalyst to produce various alcohols directly from CO2 , low productivity and low tolerance against alcohols are the main issues to be resolved. Nevertheless, to date, a mutant with increasing alcohol tolerance has rarely been reported.n this study, we attempted to select isopropanol (IPA)-tolerant mutants of Synechococcus elongatus PCC 7942 using UV-C-induced random mutagenesis, followed by enrichment of the tolerant candidates in medium containing 10 g/L IPA and screening of the cells with a high growth rate in the single cell culture system in liquid medium containing 10 g/L IPA...
April 12, 2017: Biotechnology and Bioengineering
Amel Dhib, Michel Denis, Boutheina Ziadi, Aude Barani, Souad Turki, Lotfi Aleya
In the eutrophic Ghar El Melh Lagoon (GML, Tunisia), the distribution of heterotrophic prokaryotes, pico- and nanophytoplankton was studied at five stations in November 2012 at the single cell level, along with environmental factors. Flow cytometry analysis of ultraplankton (<10 μm) resolved (i) two heterotrophic prokaryote groups, low and high nucleic acid contents (LNA and HNA, respectively), and (ii) eight to nine ultraphytoplankton groups (cryptophyte-like cells, two nanoeukaryote subgroups, two picoeukaryote subgroups and three Synechococcus-like cells subgroups)...
April 10, 2017: Environmental Science and Pollution Research International
Yohei Shimura, Yuu Hirose, Naomi Misawa, Sachiko Wakazuki, Takatomo Fujisawa, Yasukazu Nakamura, Yu Kanesaki, Haruyo Yamaguchi, Masanobu Kawachi
Members of the cyanobacterial genus Synechococcus are abundant in marine environments. To better understand the genomic diversity of marine Synechococcus spp., we determined the complete genome sequence of a coastal cyanobacterium, Synechococcus sp. NIES-970. The genome had a size of 3.1 Mb, consisting of one chromosome and four plasmids.
April 6, 2017: Genome Announcements
Katherine Rm Mackey, Anton F Post, Matthew R McIlvin, Mak A Saito
Marine Synechococcus thrive over a range of light regimes in the ocean. We examined the proteomic, genomic, and physiological responses of seven Synechococcus isolates to moderate irradiances (5-80μE m(-2) s(-1) ), and show that Synechococcus spans a continuum of light responses ranging from low light optimized (LLO) to high light optimized (HLO). These light responses are linked to phylogeny and pigmentation. Marine sub-cluster 5.1a isolates with higher phycouribilin: phycoerythrobilin ratios fell toward the LLO end of the continuum, while sub-cluster 5...
March 30, 2017: Environmental Microbiology
Arto Soitamo, Vesa Havurinne, Esa Tyystjärvi
Marine Synechococcus and Prochlorococcus cyanobacteria have different antenna compositions although they are genetically near to each other, and different strains thrive in very different illumination conditions. We measured growth and photoinhibition of PSII in two low-light and one high-light Prochlorococcus strains and in one Synechococcus strain. All strains were found to be able to shortly utilize moderate or even high light, but the low-light strains bleached rapidly in moderate light. Measurements of photoinhibition in the presence of the antibiotic lincomycin showed that a low-light Prochlorococcus strain was more sensitive than a high-light strain and both were more sensitive than the marine Synechococcus...
April 3, 2017: Physiologia Plantarum
Anna M Larsson, Dirk Hasse, Karin Valegård, Inger Andersson
Cyanobacterial CO2 fixation is promoted by encapsulating and co-localizing the CO2-fixing enzymes within a protein shell, the carboxysome. A key feature of the carboxysome is its ability to control selectively the flux of metabolites in and out of the shell. The β-carboxysome shell protein CcmP has been shown to form a double layer of pseudohexamers with a relatively large central pore (~13 Å diameter), which may allow passage of larger metabolites such as the substrate for CO2 fixation, ribulose 1,5-bisphosphate, through the shell...
March 28, 2017: Journal of Experimental Botany
Zuoxi Ruan, John A Raven, Mario Giordano
The carbon-concentrating mechanisms (CCMs) of cyanobacteria counteract the low CO2 affinity and CO2:O2 selectivities of the Rubisco of these photolithotrophs and the relatively low oceanic CO2 availability. CCMs have a significant energy cost; if light is limiting, the use of N sources whose assimilation demands less energy could permit a greater investment of energy into CCMs and inorganic C (Ci) assimilation. To test this, we cultured Synechococcus sp. UTEX LB 2380 under either N or energy limitation, in the presence of NO3- or NH4+...
March 28, 2017: Journal of Experimental Botany
Sun Young Choi, Jin-Young Wang, Ho Seok Kwak, Sun-Mi Lee, Youngsoon Um, Yunje Kim, Sang Jun Sim, Jong-Il Choi, Han Min Woo
The push-and-pull strategy for metabolic engineering was successfully demonstrated in Synechococcus elongatus PCC 7942, a model photosynthetic bacterium, to produce squalene from CO2. Squalene synthase (SQS) was fused to either a key enzyme (farnesyl diphosphate synthase) of the methylerythritol phosphate pathway or the β-subunit of phycocyanin (CpcB1). Engineered cyanobacteria with expression of a fusion CpcB1-SQS protein showed a squalene production level (7.16 ± 0.05 mg/L/OD730) that was increased by 1...
April 3, 2017: ACS Synthetic Biology
Craig MacGregor-Chatwin, Melih Sener, Samuel F H Barnett, Andrew Hitchcock, Meghan C Barnhart-Dailey, Karim Maghlaoui, James Barber, Jerilyn A Timlin, Klaus Schulten, Christopher Neil Hunter
Photosystem I (PSI) is the dominant photosystem in cyanobacteria and it plays a pivotal role in cyanobacterial metabolism. Despite its biological importance, the native organisation of PSI in cyanobacterial thylakoid membranes is poorly understood. Here, we use atomic force microscopy (AFM) to show that ordered, extensive macromolecular arrays of PSI complexes are present in thylakoids from Thermosynechococcus (T.) elongatus, Synechococcus sp. PCC 7002 and Synechocystis sp PCC 6803. Hyperspectral confocal fluorescence microscopy (HCFM) and three-dimensional structured illumination microscopy (3D-SIM) of Synechocystis sp PCC 6803 cells visualise PSI domains within the context of the complete thylakoid system...
March 31, 2017: Plant Cell
Mengge Zhang, Lianping Yang, Jie Ren, Nathan A Ahlgren, Jed A Fuhrman, Fengzhu Sun
BACKGROUND: The study of virus-host infectious association is important for understanding the functions and dynamics of microbial communities. Both cellular and fractionated viral metagenomic data generate a large number of viral contigs with missing host information. Although relative simple methods based on the similarity between the word frequency vectors of viruses and bacterial hosts have been developed to study virus-host associations, the problem is significantly understudied. We hypothesize that machine learning methods based on word frequencies can be efficiently used to study virus-host infectious associations...
March 14, 2017: BMC Bioinformatics
Shu Harn Te, Boon Fei Tan, Janelle R Thompson, Karina Yew-Hoong Gin
The identification of phytoplankton species and microbial biodiversity is necessary to assess water ecosystem health and the quality of water resources. We investigated the short-term (2 days) vertical and diel variations in bacterial community structure and microbially derived secondary metabolites during a cyanobacterial bloom that emerged in a highly urbanized tropical reservoir. The waterbody was largely dominated by the cyanobacteria Planktothricoides spp., together with the Synechococcus, Pseudanabaena, Prochlorothrix, and Limnothrix...
April 7, 2017: Environmental Science & Technology
Tingting Li, Chien-Ting Li, Kirk Butler, Stephanie G Hays, Michael T Guarnieri, George A Oyler, Michael J Betenbaugh
BACKGROUND: The feasibility of heterotrophic-phototrophic symbioses was tested via pairing of yeast strains Cryptococcus curvatus, Rhodotorula glutinis, or Saccharomyces cerevisiae with a sucrose-secreting cyanobacterium Synechococcus elongatus. RESULTS: The phototroph S. elongatus showed no growth in standard BG-11 medium with yeast extract, but grew well in BG-11 medium alone or supplemented with yeast nitrogen base without amino acids (YNB w/o aa). Among three yeast species, C...
2017: Biotechnology for Biofuels
Priscila Maria Dellamatrice, Maria Estela Silva-Stenico, Luiz Alberto Beraldo de Moraes, Marli Fátima Fiore, Regina Teresa Rosim Monteiro
Dyes are recalcitrant compounds that resist conventional biological treatments. The degradation of three textile dyes (Indigo, RBBR and Sulphur Black), and the dye-containing liquid effluent and solid waste from the Municipal Treatment Station, Americana, São Paulo, Brazil, by the cyanobacteria Anabaena flos-aquae UTCC64, Phormidium autumnale UTEX1580 and Synechococcus sp. PCC7942 was evaluated. The dye degradation efficiency of the cyanobacteria was compared with anaerobic and anaerobic-aerobic systems in terms of discolouration and toxicity evaluations...
January 2017: Brazilian Journal of Microbiology: [publication of the Brazilian Society for Microbiology]
Martin Egli
Molecular clocks are the product of natural selection in organisms from bacteria to human and their appearance early in evolution such as in the prokaryotic cyanobacterium Synechococcus elongatus suggests that these timers served a crucial role in genetic fitness. Thus, a clock allows cyanobacteria relying on photosynthesis and nitrogen fixation to temporally space the two processes and avoid exposure of nitrogenase carrying out fixation to high levels of oxygen produced during photosynthesis. Fascinating properties of molecular clocks are the long time constant, their precision and temperature compensation...
March 2017: Journal of the Royal Society, Interface
Yasutaka Hirokawa, Ryota Goto, Yoshitaka Umetani, Taizo Hanai
Using engineered cyanobacteria to produce various chemicals from carbon dioxide is a promising technology for a sustainable future. Lactate is a valuable commodity that can be used for the biodegradable plastic, polylactic acid. Typically, lactate production using engineered cyanobacteria was via the conversion of pyruvate in glycolysis by lactate dehydrogenase. In cyanobacteria, the metabolic flux in the Calvin cycle is higher than that in glycolysis under photoautotrophic conditions. The construction of a novel lactate producing pathway that uses metabolites from the Calvin cycle could potentially increase lactate productivity in cyanobacteria...
March 18, 2017: Journal of Bioscience and Bioengineering
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