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Shenzheng Zeng, Zhijian Huang, Dongwei Hou, Jian Liu, Shaoping Weng, Jianguo He
Intestinal microbiota is an integral component of the host and plays important roles in host health. The pacific white shrimp is one of the most profitable aquaculture species commercialized in the world market with the largest production in shrimp consumption. Many studies revealed that the intestinal microbiota shifted significantly during host development in other aquaculture animals. In the present study, 22 shrimp samples were collected every 15 days from larval stage (15 day post-hatching, dph) to adult stage (75 dph) to investigate the intestinal microbiota at different culture stages by targeting the V4 region of 16S rRNA gene, and the microbial function prediction was conducted by PICRUSt...
2017: PeerJ
Justine Pittera, Juliette Jouhet, Solène Breton, Laurence Garczarek, Frédéric Partensky, Éric Maréchal, Ngoc An Nguyen, Hugo Doré, Morgane Ratin, Frances D Pitt, David J Scanlan, Christophe Six
The marine cyanobacteria of the genus Synechococcus are important primary producers, displaying a wide latitudinal distribution that is underpinned by diversification into temperature ecotypes. The physiological basis underlying these ecotypes is poorly known. In many organisms, regulation of membrane fluidity is crucial for acclimating to variations in temperature. Here, we reveal the detailed composition of the membrane lipidome of the model strain Synechococcus sp. WH7803 and its response to temperature variation...
November 10, 2017: Environmental Microbiology
Travis C Korosh, Andrew L Markley, Ryan L Clark, Laura L McGinley, Katherine D McMahon, Brian F Pfleger
L-lysine and other amino acids are commonly produced through fermentation using strains of heterotrophic bacteria such as Corynebacterium glutamicum. Given the large amount of sugar this process consumes, direct photosynthetic production is intriguing alternative. In this study, we report the development of a cyanobacterium, Synechococcus sp. strain PCC 7002, capable of producing L-lysine with CO2 as the sole carbon-source. We found that heterologous expression of a lysine transporter was required to excrete lysine and avoid intracellular accumulation that correlated with poor fitness...
October 28, 2017: Metabolic Engineering
Cuncun Qiao, Yangkai Duan, Mingyi Zhang, Martin Hagemann, Quan Luo, Xuefeng Lu
Sucrose and glycogen syntheses in cyanobacteria share the common precursor glucose-1-phosphate. It is generally assumed that lowering glycogen synthesis could drive more carbon towards sucrose synthesis that can be induced by salt stress among cyanobacteria. By using a theophyllin-dependent riboswitch system, the expression of glgC, a key gene in glycogen synthesis, was down-regulated in a quantitative manner in a sucrose-secreting strain of Synechococcus elongatus PCC 7942. We observed that the stepwise suppression of glycogen synthesis limited rather than stimulated sucrose production in the salt stressed cells, suggesting that glycogen could serve as a carbon pool for the synthesis of sucrose...
November 3, 2017: Applied and Environmental Microbiology
Makiko Kosugi, Changwoo Lee, Tomonori Misaki, Yasuhiro Kashino, Morifumi Fujita, Takashi Sugimura
A unique electron-accepting analog of vitamin K1 found in photosystem I in several species of oxygenic photosynthetic microorganisms was confirmed to be 5'-hydroxyphylloquinone (1) through stereo-uncontrolled synthesis. Furthermore, the stereochemistry of 1 obtained from Synechococcus sp. PCC 7942 was assigned to be 5'S using proline-catalyzed stereocontrolled reactions.
November 3, 2017: Bioscience, Biotechnology, and Biochemistry
Minglei Ren, Guiying Zhang, Zi Ye, Zhixian Qiao, Meili Xie, Yan Lin, Tao Li, Jindong Zhao
Disentangling the interactions between cyanobacteria and associated bacterial community is important for understanding the mechanisms that mediate the formation of cyanobacterial blooms in freshwater ecosystems. Despite the fact that a metagenomic approach enables researchers to profile the structure of microbial communities associated with cyanobacteria, reconstructing genome sequences for all members remains inefficient, due to the inherent enormous microbial diversity. Here, we have established a stable coculture system under high salinity, originally from a mixture of an axenic cyanobacterium Synechococcus sp...
November 2, 2017: AMB Express
Cristiana Callieri
Cyanobacteria are among the oldest photoautotrophic organisms on Earth, and have contributed to shaping the planet's biogeochemistry with their significant biomass and key metabolic activities. Synechococcus, the focus of this review, is one of the prevalent genera in the order Chroococcales, common in oceans and lakes and characterized by a coccoid unicellular or microcolony morphology. The evolution of its phycobilisomes is the key of the adaptation of this tiny photosynthetic cell to different light regimes and environmental conditions...
October 30, 2017: FEMS Microbiology Letters
Xiaoyan Cao, Margaret R Mulholland, John R Helms, Peter W Bernhardt, Pu Duan, Jingdong Mao, Klaus Schmidt-Rohr
Dissolved organic nitrogen (DON) comprises the largest pool of fixed N in the surface ocean, yet its composition has remained poorly constrained. Knowledge of the chemical composition of this nitrogen pool is crucial for understanding its biogeochemical function and reactivity in the environment. Previous work has suggested that high-molecular-weight (high-MW) DON exists only in two closely related forms, the secondary amides of peptides and of N-acetylated hexose sugars. Here, we demonstrate that the chemical structures of high-MW DON may be much more diverse than previously thought...
October 30, 2017: Analytical Chemistry
Meilin He, Yuting Chen, Yongquan Yan, Shanmei Zhou, Changhai Wang
The ecotoxicity of α-Fe2O3 nanoparticles (NPs) and its interaction with a typical natural organic matter (NOM), fulvic acid (FA) on the physiological responses of Synechococcus sp. PCC7942 was studied. α-Fe2O3 NPs inhibited the algae growth at concentration higher than 10 mg L(-1) and induced oxidative stress, indicated by enhanced antioxidant enzymes activities, elevated protein and sugar content. FA could efficiently recover cell growth and reduce antioxidant enzyme activities which induced by α-Fe2O3 NPs, indicating the toxicity of NPs was alleviated in the presence of FA...
October 27, 2017: Bulletin of Environmental Contamination and Toxicology
Hyun Jeong Lee, Jiwon Lee, Sun-Mi Lee, Youngsoon Um, Yunje Kim, Sang Jun Sim, Jong-Il Choi, Han Min Woo
Direct conversion of carbon dioxide (CO2) to value-added chemicals by engineering of cyanobacteria has received attention as a sustainable strategy in food and chemical industries. Herein, Synechococcus elongatus PCC 7942, a model cyanobacterium, was engineered to produce α-farnesene from CO2. Due to the lack of farnesene synthase (FS) activity in the wild-type cyanobacterium, we metabolically engineered S. elongatus PCC 7942 to express heterologous FS from either Norway spruce or apple fruit, resulting in detectable peaks of α-farnesene...
October 25, 2017: Journal of Agricultural and Food Chemistry
Taylor L Weiss, Eric J Young, Daniel C Ducat
We previously reported that Synechococcus elongatus PCC 7942, engineered with the sucrose transporter CscB, can export up to 85% of its photosynthetically-fixed carbon as sucrose and shows considerable promise as an alternative carbohydrate source. One approach to effectively utilize this cyanobacterium is to generate synthetic, light-driven consortia in which sucrose-metabolizing heterotrophs catalyze the conversion of the low-value carbohydrate into higher-value compounds in co-culture. Here, we report an improved synthetic photoautotroph/chemoheterotroph consortial design in which sucrose secreted by S...
October 20, 2017: Metabolic Engineering
N Salhi, H Zmerli Triki, J C Molinero, M Laabir, E Sehli, A Bellaaj-Zouari, N Daly Yahia, O Kefi-Daly Yahia
We investigated at the single cell level during 16months (June 2012 to September 2013) the temporal distribution of picophytoplankton (picoeukaryotes, Synechococcus and Prochlorococcus) communities in two contrasted ecosystems: the Bay of Bizerte characterised by an oligotrophic regime typical of the Mediterranean Sea and the Bizerte Lagoon that exhibits a mesotrophic/eutrophic state. We aimed at depicting seasonal variations and quantifying the relationships between the environmental factors and the structure and abundance of picophytoplankton communities...
October 14, 2017: Marine Pollution Bulletin
Jessica Hartwig Duarte, Jorge Alberto Vieira Costa
LEDs have narrow wavelength bands, which can influence microalgae biomass. This study pioneers the evaluation of blue LEDs as an energy source in Chlorella fusca and Synechococcus nidulans cultures. Blue LEDs increased the specific growth rate in Synechococcus nidulans LEB 115 cultures by 80% compared to the standard light used in indoor cultivations. Moreover, blue LEDs also induced lipid accumulation in Chlorella fusca LEB 111 cells, yielding concentrations of this bioproduct of up to 23% (ww(-1)). The chlorophylls and carotenoids were photostimulated proportionally to the LED light intensity...
September 23, 2017: Bioresource Technology
Alonso M Acuña, Claire Lemaire, Rienk van Grondelle, Bruno Robert, Ivo H M van Stokkum
Excitation energy transfer (EET) and trapping in Synechococcus WH 7803 whole cells and isolated photosystem I (PSI) complexes have been studied by time-resolved emission spectroscopy at room temperature (RT) and at 77 K. With the help of global and target analysis, the pathways of EET and the charge separation dynamics have been identified. Energy absorbed in the phycobilisome (PB) rods by the abundant phycoerythrin (PE) is funneled to phycocyanin (PC645) and from there to the core that contains allophycocyanin (APC660 and APC680)...
October 13, 2017: Photosynthesis Research
Norihiro Sato, Ryohei Kamimura, Kodai Kaneta, Misato Yoshikawa, Mikio Tsuzuki
Photosynthetic organisms utilize sulfate for the synthesis of sulfur-compounds including proteins and a sulfolipid, sulfoquinovosyl diacylglycerol. Upon ambient deficiency in sulfate, cells of a green alga, Chlamydomonas reinhardtii, degrade the chloroplast membrane sulfolipid to ensure an intracellular-sulfur source for necessary protein synthesis. Here, the effects of sulfate-starvation on the sulfolipid stability were investigated in another green alga, Chlorella kessleri, and two cyanobacteria, Synechocystis sp...
2017: PloS One
Selene Casella, Fang Huang, David Mason, Guo-Yan Zhao, Giles N Johnson, Conrad W Mullineaux, Lu-Ning Liu
The structural dynamics and flexibility of cell membranes play fundamental roles in the functions of the cells, i.e., signaling, energy transduction, and physiological adaptation. The cyanobacterial thylakoid membrane represents a model membrane that can conduct both oxygenic photosynthesis and respiration simultaneously. In this study, we conducted direct visualization of the global organization and mobility of photosynthetic complexes in thylakoid membranes from a model cyanobacterium, Synechococcus elongatus PCC 7942, using high-resolution atomic force, confocal, and total internal reflection fluorescence microscopy...
November 6, 2017: Molecular Plant
Bruno S de O Silva, Felipe H Coutinho, Gustavo B Gregoracci, Luciana Leomil, Louisi S de Oliveira, Adriana Fróes, Diogo Tschoeke, Ana Carolina Soares, Anderson S Cabral, Nicholas D Ward, Jeffrey E Richey, Alex V Krusche, Patricia L Yager, Carlos Eduardo de Rezende, Cristiane C Thompson, Fabiano L Thompson
The Amazon River watershed and its associated plume comprise a vast continental and oceanic area. The microbial activities along this continuum contribute substantially to global carbon and nutrient cycling, and yet there is a dearth of information on the diversity, abundance, and possible roles of viruses in this globally important river. The aim of this study was to elucidate the diversity and structure of virus assemblages of the Amazon River-ocean continuum. Environmental viral DNA sequences were obtained for 12 locations along the river's lower reach (n = 5) and plume (n = 7)...
September 2017: MSphere
Austin D Comer, Matthew R Long, Jennifer L Reed, Brian F Pfleger
The low cost of natural gas has driven significant interest in using C1 carbon sources (e.g. methane, methanol, CO, syngas) as feedstocks for producing liquid transportation fuels and commodity chemicals. Given the large contribution of sugar and lignocellulosic feedstocks to biorefinery operating costs, natural gas and other C1 sources may provide an economic advantage. To assess the relative costs of these feedstocks, we performed flux balance analysis on genome-scale metabolic models to calculate the maximum theoretical yields of chemical products from methane, methanol, acetate, and glucose...
December 2017: Metabolic Engineering Communications
Percival J Graham, Brian Nguyen, Thomas Burdyny, David Sinton
Fluctuating light is the norm for photosynthetic organisms, with a wide range of frequencies (0.00001 to 10 Hz) owing to diurnal cycles, cloud cover, canopy shifting and mixing; with broad implications for climate change, agriculture and bioproduct production. Photosynthetic growth in fluctuating light is generally considered to improve with increasing fluctuation frequency. Here we demonstrate that the regulation of photosynthesis imposes a penalty on growth in fluctuating light for frequencies in the range of 0...
October 2, 2017: Scientific Reports
Matthew R Preimesberger, Eric A Johnson, Dillon B Nye, Juliette T J Lecomte
The cyanobacterium Synechococcus sp. PCC 7002 produces a monomeric hemoglobin (GlbN) implicated in the detoxification of reactive nitrogen and oxygen species. GlbN contains a b heme, which can be modified under certain reducing conditions. The modified protein (GlbN-A) has one heme-histidine C-N linkage similar to the C-S linkage of cytochrome c. No clear functional role has been assigned to this modification. Here, optical absorbance and NMR spectroscopies were used to compare the reactivity of GlbN and GlbN-A toward nitric oxide (NO)...
September 22, 2017: Journal of Inorganic Biochemistry
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