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Feiqiao Brian Yu, Lisa Willis, Rosanna Man Wah Chau, Alessandro Zambon, Mark Horowitz, Devaki Bhaya, Kerwyn Casey Huang, Stephen R Quake
BACKGROUND: Cyanobacteria are important agents in global carbon and nitrogen cycling and hold great promise for biotechnological applications. Model organisms such as Synechocystis sp. and Synechococcus sp. have advanced our understanding of photosynthetic capacity and circadian behavior, mostly using population-level measurements in which the behavior of individuals cannot be monitored. Synechocystis sp. cells are small and divide slowly, requiring long-term experiments to track single cells...
February 14, 2017: BMC Biology
Kenya Tanaka, Masahiro Kaneko, Masahito Ishikawa, Souichiro Kato, Hidehiro Ito, Toshiaki Kamachi, Kazuhide Kamiya, Shuji Nakanishi
Redox phospholipid polymers added in culture media are known to be capable of extracting electrons from living photosynthetic cells across bacterial cell membranes with high cytocompatibility. In the present study, we aimed to identify the intracellular redox species that transfers electrons to the polymers. The open-circuit electrochemical potential of an electrolyte containing the redox polymer and extracted thylakoid membranes shifted to positive (or negative) under light irradiation, when an electron transport inhibitor specific for the upstream (or downstream) of plastoquinone in the photosynthetic electron transport chain was added...
February 13, 2017: Chemphyschem: a European Journal of Chemical Physics and Physical Chemistry
Yoshifumi Ueno, Shimpei Aikawa, Kyosuke Niwa, Tomoko Abe, Akio Murakami, Akihiko Kondo, Seiji Akimoto
The light-harvesting antennas of oxygenic photosynthetic organisms capture light energy and transfer it to the reaction centers of their photosystems. The light-harvesting antennas of cyanobacteria and red algae, called phycobilisomes (PBSs), supply light energy to both photosystem I (PSI) and photosystem II (PSII). However, the excitation energy transfer processes from PBS to PSI and PSII are not understood in detail. In the present study, the energy transfer processes from PBS to PSs in various cyanobacteria and red algae were examined in vivo by selectively exciting their PSs or PBSs, and measuring the resulting picosecond to nanosecond time-resolved fluorescences...
February 9, 2017: Photosynthesis Research
Fang Liu, Jinlong Li, Zhiyong Li
"Candidatus Synechococcus spongiarum" represents the widespread cyanobacterial symbionts found in marine sponges with relatively high genomic variability and likely important ecological roles. We present here the draft genome sequence of "Candidatus Synechococcus spongiarum" m9, which was assembled from a metagenome of Theonella swinhoei sampled in the South China Sea.
February 9, 2017: Genome Announcements
Matthew D Ooms, Percival J Graham, Brian Nguyen, Edward H Sargent, David Sinton
The spectral distribution of light influences microalgae productivity; however, development of photobioreactors has proceeded largely without regard to spectral optimization. Here we use monochromatic light to quantify the joint influence of path length, culture density, light intensity and wavelength on productivity and efficiency in Synechococcus elongatus. The productivity of green light was ∼4 x that of red at the highest levels of culture density, depth and light intensity. This performance is attributed to the combination of increased dilution and penetration of this weakly absorbed wavelength over a larger volume fraction of the reactor...
February 6, 2017: Biotechnology and Bioengineering
Zheng-Ke Li, Guo-Zheng Dai, Philippe Juneau, Bao-Sheng Qiu
Iron deficiency has been considered one of the main limiting factors of phytoplankton productivity in some aquatic systems including oceans and lakes. Concomitantly, solar ultraviolet-B radiation has been shown to have both deleterious and positive impacts on phytoplankton productivity. However, how iron-deficient cyanobacteria respond to UV-B radiation has been largely overlooked in aquatic systems. In this study, physiological responses of four cyanobacterial strains (Microcystis and Synechococcus), which are widely distributed in freshwater or marine systems, were investigated under different UV-B irradiances and iron conditions...
February 6, 2017: Journal of Phycology
Steven E Baer, Michael W Lomas, Kristina X Terpis, Celine Mouginot, Adam C Martiny
In the North Atlantic Ocean, we found that natural populations of Prochlorococcus adhered to Redfield ratio dimensions when comparing cell quotas of carbon to nitrogen, but had flexible composition under nutrient and light stress, allowing for a broad range of cellular carbon- and nitrogen-to-phosphorus ratios. Synechococcus populations also exhibited a wide range of elemental stoichiometry, including carbon-to-nitrogen ratios and increased their carbon-to-phosphorus ratios in response to low dissolved phosphorus availability...
January 31, 2017: Environmental Microbiology
Thomas J Mueller, Justin L Ungerer, Himadri B Pakrasi, Costas D Maranas
The photosynthetic capabilities of cyanobacteria make them interesting candidates for industrial bioproduction. One obstacle to large-scale implementation of cyanobacteria is their limited growth rates as compared to industrial mainstays. Synechococcus UTEX 2973, a strain closely related to Synechococcus PCC 7942, was recently identified as having the fastest measured growth rate among cyanobacteria. To facilitate the development of 2973 as a model organism we developed in this study the genome-scale metabolic model iSyu683...
January 31, 2017: Scientific Reports
Xin Jiang, Jiajun Li, Zhixin Ke, Chenhui Xiang, Yehui Tan, Liangmin Huang
To understand the variations of picoplankton (Prochlorococcus, Synechococcus, picoeukaryotes, and heterotrophic bacteria) abundances during diatom bloom, the distribution of picoplankton in the Taiwan Bank, South China Sea was investigated using flow cytometry during a Thalassiosira diporocyclus bloom in March 2016. The results indicated an abrupt abundance decrease for Prochlorococcus, Synechococcus, and picoeukaryotes within the bloom area while the abundance of heterotrophic bacteria showed no significant difference between the bloom and non-bloom areas...
January 27, 2017: Marine Pollution Bulletin
Cole D Murphy, Mitchell S Roodvoets, Emily J Austen, Allison Dolan, Audrey Barnett, Douglas A Campbell
The marine picocyanobacteria Synechococcus and Prochlorococcus numerically dominate open ocean phytoplankton. Although evolutionarily related they are ecologically distinct, with different strategies to harvest, manage and exploit light. We grew representative strains of Synechococcus and Prochlorococcus and tracked their susceptibility to photoinactivation of Photosystem II under a range of light levels. As expected blue light provoked more rapid photoinactivation than did an equivalent level of red light...
2017: PloS One
Hyun Jeong Lee, Jaeyeon Choi, Sun-Mi Lee, Youngsoon Um, Sang Jun Sim, Yunje Kim, Han Min Woo
Metabolic engineering of cyanobacteria has received attention as a sustainable strategy to convert carbon dioxide to fatty acid-derived chemicals that are widely used in the food and chemical industries. Herein, Synechococcus elongatus PCC 7942, a model cyanobacterium, was engineered for the first time to produce fatty acid ethyl esters (FAEEs) from CO2. Due to the lack of an endogenous ethanol production pathway and wax ester synthase (AftA) activity in the wild-type cyanobacterium, we metabolically engineered S...
February 2, 2017: Journal of Agricultural and Food Chemistry
Stephanie G Hays, Leo L W Yan, Pamela A Silver, Daniel C Ducat
BACKGROUND: Microbial consortia composed of autotrophic and heterotrophic species abound in nature, yet examples of synthetic communities with mixed metabolism are limited in the laboratory. We previously engineered a model cyanobacterium, Synechococcus elongatus PCC 7942, to secrete the bulk of the carbon it fixes as sucrose, a carbohydrate that can be utilized by many other microbes. Here, we tested the capability of sucrose-secreting cyanobacteria to act as a flexible platform for the construction of synthetic, light-driven consortia by pairing them with three disparate heterotrophs: Bacillus subtilis, Escherichia coli, or Saccharomyces cerevisiae...
2017: Journal of Biological Engineering
Xi Peng, Jie Yang, Yang Gao
UV-C's effects on the physiological and biochemical processes of cyanobacteria have been well characterized. However, the molecular mechanisms of cyanobacteria's tolerance to UV-C still needs further investigation. This research attempts to decode the variation in protein abundances in cyanobacteria after UV-C stress. Different expression levels of proteins in the cytoplasm of Synechococcus sp. PCC7942 under UV-C stress were investigated by using a comparative proteomic approach. Forty-seven UV-C-regulated proteins were identified by MALDI-TOF analysis and classified by Gene Ontology (GO)...
January 25, 2017: Photochemistry and Photobiology
Otto X Cordero
A recent genomic analysis of Synechococcus cyanophages sampled for over 15 years reveals a remarkable pattern of stable phage population structure, highly reminiscent of the ecotype structure observed in bacteria and archaeal ecotypes. In this highlight I discuss the importance of this finding and the questions and opportunities it opens to learn more about the nature of phage-bacterial coevolution in the environment. This article is protected by copyright. All rights reserved.
January 20, 2017: Environmental Microbiology
Arindam Ghatak, Nagakumar Bharatham, Anirudh P Shanbhag, Santanu Datta, Janani Venkatraman
Short-chain dehydrogenase reductases (SDRs) have been utilized for catalyzing the reduction of many aromatic/aliphatic prochiral ketones to their respective alcohols. However, there is a paucity of data that elucidates their innate biological role and diverse substrate space. In this study, we executed an in-depth biochemical characterization and substrate space mapping (with 278 prochiral ketones) of an unannotated SDR (DHK) from Debaryomyces hansenii and compared it with structurally and functionally characterized SDR Synechococcus elongatus...
2017: PloS One
Ikki Kobayashi, Satoru Watanabe, Yu Kanesaki, Tomohiro Shimada, Hirofumi Yoshikawa, Kan Tanaka
Bacteria and other organisms, including cyanobacteria, employ two-component signal transducing modules comprising histidine kinases and response regulators to acclimate to changing environments. While the number and composition of these modules differ among cyanobacteria, two response regulators that contain DNA binding domains, RpaB and Rre1, are conserved in all sequenced cyanobacterial genomes and are essential for viability. Although RpaB negatively or positively regulates high light and other stress-responsive gene expression, little is known about the function of Rre1...
January 20, 2017: Molecular Microbiology
Eric A Hill, William B Chrisler, Alex S Beliaev, Hans C Bernstein
A new co-cultivation technology is presented that converts greenhouse gasses, CH4 and CO2, into microbial biomass. The methanotrophic bacterium, Methylomicrobium alcaliphilum 20z, was coupled to a cyanobacterium, Synechococcus PCC 7002 via oxygenic photosynthesis. The system exhibited robust growth on diverse gas mixtures ranging from biogas to those representative of a natural gas feedstock. A continuous processes was developed on a synthetic natural gas feed that achieved steady-state by imposing coupled light and O2 limitations on the cyanobacterium and methanotroph, respectively...
March 2017: Bioresource Technology
Spencer Diamond, Benjamin E Rubin, Ryan K Shultzaberger, You Chen, Chase D Barber, Susan S Golden
Cyanobacteria evolved a robust circadian clock, which has a profound influence on fitness and metabolism under daily light-dark (LD) cycles. In the model cyanobacterium Synechococcus elongatus PCC 7942, a functional clock is not required for diurnal growth, but mutants defective for the response regulator that mediates transcriptional rhythms in the wild-type, regulator of phycobilisome association A (RpaA), cannot be cultured under LD conditions. We found that rpaA-null mutants are inviable after several hours in the dark and compared the metabolomes of wild-type and rpaA-null strains to identify the source of lethality...
January 24, 2017: Proceedings of the National Academy of Sciences of the United States of America
Apostolos-Manuel Koussoroplis, Anke Schwarzenberger, Alexander Wacker
We studied the short- (12 h) and long-term (144 h) response of Daphnia pulex lipases to quality shifts in diets consisting of different mixtures of the green alga Scenedesmus with the cyanobacterium Synechococcus, two species with contrasting lipid compositions. The lipase/esterase activity in both the gut and the body tissues had fast responses to the diet shift and increased with higher dietary contributions of Synechococcus When screening the Daphnia genome for TAG lipases, we discovered a large gene-family expansion of these enzymes...
February 15, 2017: Biology Open
Richard Baran, Rebecca Lau, Benjamin P Bowen, Spencer Diamond, Nick Jose, Ferran Garcia-Pichel, Trent R Northen
Cyanobacteria are important primary producers of organic matter in diverse environments on a global scale. While mechanisms of CO2 fixation are well understood, the distribution of the flow of fixed organic carbon within individual cells and complex microbial communities is less well characterized. To obtain a general overview of metabolism, we describe the use of deuterium oxide (D2O) to measure deuterium incorporation into the intracellular metabolites of two physiologically diverse cyanobacteria: a terrestrial filamentous strain (Microcoleus vaginatus PCC 9802) and a euryhaline unicellular strain (Synechococcus sp...
January 18, 2017: ACS Chemical Biology
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