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Hong Yu, Xiaoqian Li, Fabienne Duchoud, Derrick S Chuang, James C Liao
The Calvin-Benson-Bassham (CBB) cycle is presumably evolved for optimal synthesis of C3 sugars, but not for the production of C2 metabolite acetyl-CoA. The carbon loss in producing acetyl-CoA from decarboxylation of C3 sugar limits the maximum carbon yield of photosynthesis. Here we design a synthetic malyl-CoA-glycerate (MCG) pathway to augment the CBB cycle for efficient acetyl-CoA synthesis. This pathway converts a C3 metabolite to two acetyl-CoA by fixation of one additional CO2 equivalent, or assimilates glyoxylate, a photorespiration intermediate, to produce acetyl-CoA without net carbon loss...
May 22, 2018: Nature Communications
Silvia C Bobeica, Wilfred A van der Donk
Lanthipeptides are ribosomally synthesized and posttranslationally modified peptides containing thioether cross-links formed through addition of a cysteine to a dehydroalanine (to form lanthionine) or to a dehydrobutyrine (to form 3-methyllanthionine). Genome sequencing of marine cyanobacteria lead to the discovery of 1.6 million open reading frames encoding lanthipeptides. In many cases, a genome encodes a single lanthipeptide synthetase, but a large number of substrates. The enzymatic modification process in Prochlorococcus MIT9313 has been reconstituted in vitro, and a variety of experimental approaches have been used to try and understand how one enzyme is capable of modifying 30 different substrates...
2018: Methods in Enzymology
Samantha Serra Costa, Andréa Lobo Miranda, Bianca Bomfim Andrade, Denilson de Jesus Assis, Carolina Oliveira Souza, Michele Greque de Morais, Jorge Alberto Vieira Costa, Janice Izabel Druzian
This study sought to evaluate influence of nitrogen availability on cell growth, biomass composition, production, and the properties of polyhydroxyalkanoates during cultivation of microalgae Chlorella minutissima, Synechococcus subsalsus, and Spirulina sp. LEB-18. The cellular growth of microalgae reduced with the use of limited nitrogen medium, demonstrating that nitrogen deficiency interferes with the metabolism of microorganisms and the production of biomass. The biochemical composition of microalgae was also altered, which was most notable in the degradation of proteins and chlorophylls and the accumulation of carbonaceous storage molecules such as lipids and polyhydroxyalkanoates...
May 12, 2018: International Journal of Biological Macromolecules
Matthew J Smith, Matthew B Francis
This work is motivated by both (1) the desire to make interesting products without the reliance on fixed carbon or fixed nitrogen using microbial cocultures, and (2) the desire to develop new methods for growing microbial communities. The bioplastic polyhydroxybutyrate (PHB), for example, is considered prohibitively expensive to make from sugar (compared to polypropylene). Utilizing and building on engineered strains of Synechococcus elongatus and Azotobacter vinelandii, we have combined a nitrogen-fixing organism with a carbon-fixing organism to make PHB from air, water, sunlight, and trace minerals...
2018: Methods in Molecular Biology
Guipeng Hu, Jie Zhou, Xiulai Chen, Yuanyuan Qian, Cong Gao, Liang Guo, Peng Xu, Wei Chen, Jian Chen, Yin Li, Liming Liu
Increasing the microbial CO2 -fixing efficiency often requires supplying sufficient ATP and redirecting carbon flux for the production of metabolites. However, addressing these two issues concurrently remains a challenge. Here, we present a combinational strategy based on a synergetic CO2 -fixing pathway that combines an ATP-generating carboxylation reaction in the central metabolic pathway with the ATP-consuming RuBisCO shunt in the carbon fixation pathway. This strategy provides enough ATP to improve the efficiency of CO2 fixation and simultaneously rewires the CO2 -fixing pathway to the central metabolic pathway for the biosynthesis of chemicals...
May 10, 2018: Metabolic Engineering
Xiaoyan Jing, Honglei Gou, Yanhai Gong, Xiaolu Su, La Xu, Yuetong Ji, Yizhi Song, Ian P Thompson, Jian Xu, Wei E Huang
It is of great significance to understand CO2 fixation in the oceans. Using single cell Raman spectra (SCRS) as biochemical profiles, Raman activated cell ejection (RACE) was able to link phenotypes and genotypes of cells. Here we show that mini-metagenomic sequences from RACE can be used as a reference to reconstruct nearly complete genomes of key functional bacteria by binning shotgun metagenomic sequencing data. By applying this approach to 13 C-bicarbonate spiked seawater from euphotic zone of the Yellow Sea of China, the dominant bacteria Synechococcus spp...
May 4, 2018: Environmental Microbiology
Damini Jaiswal, Charulata B Prasannan, John I Hendry, Pramod P Wangikar
Accurate quantification of Mass Isotopologue Distribution (MID) of metabolites is a prerequisite for 13C-metabolic flux analysis. Currently used mass spectrometric (MS) techniques based on multiple reaction monitoring (MRM) place limitations on the number of MIDs that can be analyzed in a single run. Moreover, the deconvolution step results in amplification of error. Here, we demonstrate that SWATH MS/MS, a data independent acquisition (DIA) technique allows quantification of a large number of precursor and product MIDs in a single run...
April 30, 2018: Analytical Chemistry
Cristina Díez-Vives, Ana I S Esteves, Rodrigo Costa, Shaun Nielsen, Torsten Thomas
Sponges interact with diverse and rich communities of bacteria that are phylogenetically often distinct from their free-living counterparts. Recent genomics and metagenomic studies have indicated that bacterial sponge symbionts also have distinct functional features from free-living bacteria, however it is unclear, if such genome-derived functional signatures are common and present in different symbiont taxa. We therefore compared here a large set of genomes from cultured (Pseudovibrio, Ruegeria, Aquimarina) and yet-uncultivated (Synechococcus) bacteria found either in sponge-associated or free-living sources...
April 30, 2018: Environmental Microbiology Reports
Sreejith Kottuparambil, Susana Agusti
In this study, we investigated the in situ responses of Red Sea picophytoplankton, the dominant phytoplankton group in the oligotrophic ocean, to two toxic polycyclic aromatic hydrocarbons (PAHs), phenanthrene and pyrene. The experiments were conducted across a latitudinal gradient of the Saudi Arabian Red Sea, an area sensitive to oil pollution. We observed significant adverse effects on the growth and abundance of the picocyanobacteria Synechococcus and picoeukaryotes, at all stations sampled. Prochlorococcus, which was abundant only at one of the stations, also appeared to be affected...
April 25, 2018: Environmental Pollution
Emilio Marañón, María P Lorenzo, Pedro Cermeño, Beatriz Mouriño-Carballido
Climate warming has the potential to alter ecosystem function through temperature-dependent changes in individual metabolic rates. The temperature sensitivity of phytoplankton metabolism is especially relevant, since these microorganisms sustain marine food webs and are major drivers of biogeochemical cycling. Phytoplankton metabolic rates increase with temperature when nutrients are abundant, but it is unknown if the same pattern applies under nutrient-limited growth conditions, which prevail over most of the ocean...
April 25, 2018: ISME Journal
Ganta Upendar, Sunita Singh, Jitamanyu Chakrabarty, Kartik Chandra Ghanta, Susmita Dutta, Abhishek Dutta
A cyanobacterial strain, Synechococcus sp. NIT18, has been applied to sequester CO2 using sodium carbonate as inorganic carbon source due to its efficiency of CO2 bioconversion and high biomass production. The biomass obtained is used for the extraction of biomolecules - protein, carbohydrate and lipid. The main objective of the study is to maximize the biomass and biomolecules production with CO2 sequestration using cyanobacterial strain cultivated under different concentrations of CO2 (5-20%), pH (7-11) and inoculum size (5-12...
April 19, 2018: Journal of Environmental Management
Andrea Di Cesare, Pedro J Cabello-Yeves, Nathan A M Chrismas, Patricia Sánchez-Baracaldo, Michaela M Salcher, Cristiana Callieri
BACKGROUND: Many cyanobacteria are capable of fixing atmospheric nitrogen, playing a crucial role in biogeochemical cycling. Little is known about freshwater unicellular cyanobacteria Synechococcus spp. at the genomic level, despite being recognised of considerable ecological importance in aquatic ecosystems. So far, it has not been shown whether these unicellular picocyanobacteria have the potential for nitrogen fixation. Here, we present the draft-genome of the new pink-pigmented Synechococcus-like strain Vulcanococcus limneticus...
April 16, 2018: BMC Genomics
Yuqiu Wei, Jun Sun, Xiaodong Zhang, Jing Wang, Ke Huang
The cellular size and biomass of picophytoplankton were studied by flow cytometer during spring monsoon (March-May of 2015) in equatorial eastern Indian Ocean. We established an empirical relationship between forward scatter and cellular size to address the size and biomass of picophytoplankton. Results indicated that mean cell diameter of Prochlorococcus (0.60 μm) was the smallest, and then followed by Synechococcus (0.98 μm) and picoeukaryotic phytoplankton (1.05 μm). Thereafter, the biomass converted by abundance reached 0...
April 15, 2018: MicrobiologyOpen
Lin-Rui Tan, Peng-Fei Xia, Raymond J Zeng, Qian Li, Xue-Fei Sun, Shu-Guang Wang
The interactions between antibiotics and microorganisms have attracted enormous research attentions. In this study, we investigated the effects of two typical aminoglycoside antibiotics on the aggregation of the model cyanobacterium, Synechococcus elongatus, and the dominating strain in algal blooms, Microcystis aeruginosa, via the analysis of zeta potentials, hydrophobicity, and extracellular polymeric substances (EPS) secretion. The results showed that low-level antibiotics promoted the aggregation of S. elongatus and M...
April 11, 2018: Environmental Science and Pollution Research International
Divya T V, Pallavi Chandwadkar, Celin Acharya
Metallothioneins (MTs) are low molecular weight, sulfhydryl-containing, cysteine-rich, metal-binding proteins. Eukaryotes have multiple metallothionein genes; however, there is dearth of reports on prokaryotic metallothioneins. Bacterial MTs with SmtA from Synechococcus PCC 7942 as prototype have been studied in the context of cadmium detoxification. In this study, a smtA related ORF, namely nmtA, was identified in the heterocystous, nitrogen-fixing cyanobacterium, Anabaena PCC 7120. A recombinant N-terminal histidine-tagged Anabaena NmtA protein was overexpressed in Escherichia coli and purified...
March 30, 2018: Aquatic Toxicology
Lili Tang, Zenghu Zhang, Chao Zhou, Rong Cui, Yu Tian, Yongyu Zhang
A novel Gram-stain-negative, aerobic, non-flagellated, pink-pigmented and rod-shaped strain with gliding motility, designated strain CCMM001T , was isolated from a mixed culture of Synechococcus species PCC7002 and a natural bacterial community from a sample of offshore seawater from Qingdao, China, during September 2014. The strain contained bacteriochlorophyll a with a small peak at 802 nm and a large in vivo absorption band at 870 nm. Strain CCMM001T grew optimally at pH 7.0 and 30 °C in the presence of 3 % (w/v) NaCl...
April 5, 2018: International Journal of Systematic and Evolutionary Microbiology
Xiao Qian, Yuan Zhang, Desmond S Lun, G Charles Dismukes
Boosting cellular growth rates while redirecting metabolism to make desired products are the preeminent goals sought by gene engineering of photoautotrophs, yet so far has under achieved owing to lack of understanding of the functional pathways and their choke points. Here we apply a 13C mass isotopic method (INST-MFA) to quantify instantaneous fluxes of metabolites during photoautotrophic growth. INST-MFA determines the globally most accurate set of absolute fluxes for each metabolite from a finite set of measured 13C-isotopomer fluxes by minimizing the sum of squared residuals between experimental and predicted mass isotopomers...
April 4, 2018: ACS Synthetic Biology
Benjamin E Rubin, TuAnh Ngoc Huynh, David G Welkie, Spencer Diamond, Ryan Simkovsky, Emily C Pierce, Arnaud Taton, Laura C Lowe, Jenny J Lee, Scott A Rifkin, Joshua J Woodward, Susan S Golden
The broadly conserved signaling nucleotide cyclic di-adenosine monophosphate (c-di-AMP) is essential for viability in most bacteria where it has been studied. However, characterization of the cellular functions and metabolism of c-di-AMP has largely been confined to the class Bacilli, limiting our functional understanding of the molecule among diverse phyla. We identified the cyclase responsible for c-di-AMP synthesis and characterized the molecule's role in survival of darkness in the model photosynthetic cyanobacterium Synechococcus elongatus PCC 7942...
April 2, 2018: PLoS Genetics
Yeong Du Yoo, Kyeong Ah Seong, Hyung Seop Kim, Hae Jin Jeong, Eun Young Yoon, Jaeyeon Park, Jong Im Kim, Woongghi Shin, Brian Palenik
The phototrophic euglenophyte Eutreptiella eupharyngea often causes blooms in the coastal waters of many countries, but its mode of nutrition has not been assessed. This species has previously been considered as exclusively auxotrophic. To explore whether E. eupharyngea is a mixotrophic species, the protoplasm of E. eupharyngea cells were examined using light, epifluorescence, and transmission electron microscopy after eubacteria, the cyanobacterium Synechococcus sp., and diverse algal species were provided as potential prey...
March 2018: Harmful Algae
Nathan S Hall, R Wayne Litaker, W Judson Kenworthy, Mark W Vandersea, William G Sunda, James P Reid, Daniel H Slone, Susan Butler
A brown tide bloom of Aureoumbra lagunensis developed in Guantánamo Bay, Cuba during a period of drought in 2013 that followed heavy winds and rainfall from Hurricane Sandy in late October 2012. Based on satellite images and water turbidity measurements, the bloom appeared to initiate in January 2013. The causative species (A. lagunensis) was confirmed by microscopic observation, and pigment and genetic analyses of bloom samples collected on May 28 of that year. During that time, A. lagunensis reached concentrations of 900,000 cells ml-1 (28 ppm by biovolume) in the middle portion of the Bay...
March 2018: Harmful Algae
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