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Remedios Guzmán-Guillén, Alexandre Campos, Joana Machado, Marisa Freitas, Joana Azevedo, Edgar Pinto, Agostinho Almeida, Ana M Cameán, Vitor Vasconcelos
Natural toxins produced by freshwater cyanobacteria, such as cylindrospermopsin, have been regarded as an emergent environmental threat. Despite the risks for food safety, the impact of these water contaminants in agriculture is not yet fully understood. Carrots (Daucus carota) are root vegetables, extensively consumed worldwide with great importance for human nourishment and economy. It is, therefore, important to evaluate the possible effects of using water contaminated with cyanotoxins on carrot cultivation...
October 21, 2016: Ecotoxicology
Shengwei Hou, Ulrike Pfreundt, Dan Miller, Ilana Berman-Frank, Wolfgang R Hess
Metatranscriptomic differential RNA-Seq (mdRNA-Seq) identifies the suite of active transcriptional start sites at single-nucleotide resolution through enrichment of primary transcript 5' ends. Here we analyzed the microbial community at 45 m depth at Station A in the northern Gulf of Aqaba, Red Sea, during 500 m deep mixing in February 2012 using mdRNA-Seq and a parallel classical RNA-Seq approach. We identified promoters active in situ for five different pico-planktonic genera (the SAR11 clade of Alphaproteobacteria, Synechococcus of Cyanobacteria, Euryarchaeota, Thaumarchaeota, and Micromonas as an example for picoeukaryotic algae), showing the applicability of this approach to highly diverse microbial communities...
October 19, 2016: Scientific Reports
Ya Qin, Jie Hou, Ming Deng, Quansheng Liu, Chongwei Wu, Yingjie Ji, Xugang He
The abundance and diversity of bacteria in two types of ponds were investigated by quantitative PCR and Illumina MiSeq sequencing. The results revealed that the abundance of bacterial 16S rRNA genes in D ponds (with grass carp fed sudan grass) was significantly lower than that in E ponds (with grass carp fed commercial feed). The microbial communities were dominated by Proteobacteria, Cyanobacteria, Bacteroidetes, and Actinobacteria in both E and D ponds, while the abundance of some genera was significantly different between the two types of ponds...
October 19, 2016: Scientific Reports
Yunpeng Wang, Lei Chen, Weiwen Zhang
BACKGROUND: 3-hydroxypropionic acid (3-HP) is an important platform chemical with a wide range of applications. In our previous study, the biosynthetic pathway of 3-HP was constructed and optimized in cyanobacterium Synechocystis sp. PCC 6803, which led to 3-HP production directly from CO2 at a level of 837.18 mg L(-1) (348.8 mg/g dry cell weight). As the production and accumulation of 3-HP in cells affect cellular metabolism, a better understanding of cellular responses to 3-HP synthesized internally in Synechocystis will be important for further increasing 3-HP productivity in cyanobacterial chassis...
2016: Biotechnology for Biofuels
Akira Umehara, Tohru Takahashi, Tomohiro Komorita, Ryo Orita, Jin-Woo Choi, Risa Takenaka, Rie Mabuchi, Ho-Dong Park, Hiroaki Tsutsumi
Freshwater cyanobacteria produce toxic microcystins (MCs), which travel from freshwater areas into the sea. The MCs produced by cyanobacteria in a freshwater reservoir were discharged frequently into the adjacent Isahaya Bay, remained in the surface sediments, and then accumulated in various macrobenthic animals on the seafloor. The MCs were transported further outside of Isahaya Bay (Ariake Bay), and the median values of the MC contents in the sediments were in the same levels in both bays, while their temporal variations were also similar during the study period...
October 15, 2016: Chemosphere
Nikolai N Sluchanko, Konstantin E Klementiev, Evgeny A Shirshin, Georgy V Tsoraev, Thomas Friedrich, Eugene G Maksimov
In Cyanobacteria, the Orange Carotenoid Protein (OCP) and Fluorescence Recovery Protein (FRP) are central to the photoprotective mechanism consisting in regulated quenching of phycobilisome (PBs) fluorescence. Due to a transient and flexible nature of the light-activated red quenching form, OCP(R), which is obtained from the stable dark-adapted orange form, OCP(O), by photoconversion, the detailed mechanism of photoprotection remains unclear. Here we demonstrate that our recently described W288A mutant of the Synechocystis OCP (hereinafter called OCP(W288A)) is a fully functional analogue of the OCP(R) form which is capable of constitutive PBs fluorescence quenching in vitro with no need of photoactivation...
October 15, 2016: Biochimica et Biophysica Acta
Diane M Orihel, David W Schindler, Nathaniel C Ballard, Lindsey R Wilson, Rolf D Vinebrooke
The effects of reducing nutrient inputs to lakes and reservoirs are often delayed by hysteresis resulting from internal phosphorus (P) loading from sediments. Consequently, controlling harmful algal blooms (HABs) in many eutrophic ecosystems requires additional management to improve water quality. We manipulated iron (Fe) concentrations in a hypereutrophic lake to determine if Fe amendment would suppress HABs by inhibiting P release from sediments. Our experiment consisted of 15 in situ mesocosms, 12 of which each received a different dose of Fe (ranging from 2 to 225 g/m(2) ); the remaining three were unmanipulated to serve as controls...
July 2016: Ecological Applications: a Publication of the Ecological Society of America
M A Sinetova, D A Los
Systemic analysis of stress transcriptomes of the cyanobacterium Synechocystis revealed that all stress-induced genes can be separated into two groups: one is clustered around heat-shock- and another - around cold-shock inducible genes. Genes for so-called heat shock proteins (HSPs) are induced by various stressors, e.g. heat, salt, hyperosmotic environment, reactive oxygen species (ROS), changes in light intensity and quality, or in the redox potential of the photosynthetic electron transport chain components...
October 18, 2016: Molecular BioSystems
Mónica Rouco, Sheean T Haley, Harriet Alexander, Samuel T Wilson, David M Karl, Sonya T Dyhrman
Populations of nitrogen-fixing cyanobacteria in the genus Trichodesmium are critical to ocean ecosystems, yet predicting patterns of Trichodesmium distribution and their role in ocean biogeochemistry is an ongoing challenge. This may, in part, be due to differences in the physiological ecology of Trichodesmium species, which are not typically considered independently in field studies. In this study, the abundance of the two dominant Trichodesmium clades (Clade I and Clade III) was investigated during a survey at Station ALOHA in the North Pacific Subtropical Gyre (NPSG) using a clade-specific qPCR approach...
October 18, 2016: Environmental Microbiology Reports
Elżbieta Zębek, Agnieszka Napiórkowska-Krzebietke
Lake Jeziorak Mały is a shallow urban lake where storm water pretreatment separators and a fountain-based water aeration system were installed as protective-restoration measures to enhance water quality. We investigated the effect of these procedures on phytoplankton dynamics and physicochemical properties in the littoral and pelagial zones in 1996-2003, 2005, and 2013. A decrease in cyanobacteria proportion, abundance, and biomass has been noticed, and other phytoplankton groups increased after these procedures...
November 2016: Environmental Monitoring and Assessment
Yizhi Song, Anne-Kristin Kaster, John Vollmers, Yanqing Song, Paul A Davison, Martinique Frentrup, Gail M Preston, Ian P Thompson, J Colin Murrell, Huabing Yin, C Neil Hunter, Wei E Huang
Cell sorting coupled with single-cell genomics is a powerful tool to circumvent cultivation of microorganisms and reveal microbial 'dark matter'. Single-cell Raman spectra (SCRSs) are label-free biochemical 'fingerprints' of individual cells, which can link the sorted cells to their phenotypic information and ecological functions. We employed a novel Raman-activated cell ejection (RACE) approach to sort single bacterial cells from a water sample in the Red Sea based on SCRS. Carotenoids are highly diverse pigments and play an important role in phototrophic bacteria, giving strong and distinctive Raman spectra...
October 17, 2016: Microbial Biotechnology
Isabella Bertani, Cara E Steger, Daniel R Obenour, Gary L Fahnenstiel, Thomas B Bridgeman, Thomas H Johengen, Michael J Sayers, Robert A Shuchman, Donald Scavia
Cyanobacteria blooms are a major environmental issue worldwide. Our understanding of the biophysical processes driving cyanobacterial proliferation and the ability to develop predictive models that inform resource managers and policy makers rely upon the accurate characterization of bloom dynamics. Models quantifying relationships between bloom severity and environmental drivers are often calibrated to an individual set of bloom observations, and few studies have assessed whether differences among observing platforms could lead to contrasting results in terms of relevant bloom predictors and their estimated influence on bloom severity...
October 12, 2016: Science of the Total Environment
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
Madhuri A Inupakutika, Soham Sengupta, Amith R Devireddy, Rajeev K Azad, Ron Mittler
Reactive oxygen species (ROS) play a key role in the regulation of many biological processes in plants. Nonetheless, they are considered highly reactive and toxic to cells. Owing to their toxicity, as well as their important role in signaling, the level of ROS in cells needs to be tightly regulated. The ROS gene network, encoding a highly redundant arsenal of ROS scavenging mechanisms and an array of enzymes involved in ROS production, regulates ROS metabolism and signaling in plants. In this article, we review the role of the ROS gene network in plants and examine how it evolved...
October 14, 2016: Journal of Experimental Botany
Natalie C Sadler, Hans C Bernstein, Matthew R Melnicki, Moiz A Charania, Eric A Hill, Lindsey N Anderson, Matthew E Monroe, Richard D Smith, Alexander S Beliaev, Aaron T Wright
: Photobiologically synthesized hydrogen (H2) gas is carbon-neutral to produce and clean to combust, making it an ideal biofuel. Cyanothece sp. ATCC 51142 is a cyanobacterium capable of performing simultaneous oxygenic photosynthesis and H2 production, a highly perplexing phenomenon because H2 evolving enzymes are O2-sensitive. We employed a systems-level in vivo chemoproteomic profiling approach to explore the cellular dynamics of protein thiol redox, and how thiol redox mediates the function of the dinitrogenase NifHDK, an enzyme complex capable of aerobic hydrogenase activity...
October 14, 2016: Applied and Environmental Microbiology
Qinghuan Xu, Lin Yang, Wangting Yang, Yan Bai, Ping Hou, Jingxian Zhao, Lv Zhou, Zhaojiang Zuo
Eutrophication promotes massive growth of cyanobacteria and algal blooms, which can poison other algae and reduce biodiversity. To investigate the differences in multiple nitrogen (N) sources in eutrophicated water on the emission of volatile organic compounds (VOCs) from cyanobacteria, and their toxic effects on other algal growth, we analyzed VOCs emitted from Microcystis flos-aquae with different types and concentrations of nitrogen, and determined the effects under Normal-N and Non-N conditions on Chlorella vulgaris...
October 11, 2016: Ecotoxicology and Environmental Safety
Khoa Nguyen, Michael Vaughn, Paul Frymier, Barry D Bruce
The reduction rate of photo-oxidized Photosystem I (PSI) with various natural and artificial electron donors have been well studied by transient absorption spectroscopy. The electron transfer rate from various donors to P700(+) has been measured for a wide range of photosynthetic organisms encompassing cyanobacteria, algae, and plants. PSI can be a limiting component due to tedious extraction and purification methods required for this membrane protein. In this report, we have determined the in vivo, intracellular cytochrome c 6 (cyt c 6)/PSI ratio in Thermosynechococcus elongatus (T...
October 13, 2016: Photosynthesis Research
Shu Harn Te, Boon Fei Tan, Janelle R Thompson, Karina Yew-Hoong Gin
Genomes of two filamentous benthic cyanobacteria were obtained from cocultures obtained from two freshwater lakes. The cultures were obtained by first growing cyanobacterial trichome on solid medium, followed by subculturing in freshwater media. Subsequent shotgun sequencing, de novo assembly, and genomic binning yielded almost complete genomes of Oscillatoriales USR 001 and Nostoc sp. MBR 210.
October 13, 2016: Genome Announcements
Sabine A Ragot, Michael A Kertesz, Éva Mészáros, Emmanuel Frossard, Else K Bünemann
Alkaline phosphatases such as PhoD and PhoX are important genes in organic phosphorus cycling in soil. We identified the key organisms harboring the phoD and phoX gene in soil and explored the relationships between environmental factors and the phoD- and phoX-harboring community structures across three land-uses located in arid to temperate climates on two continents using 454-sequencing. phoD was investigated using recently published primers, and new primers were designed to study phoX in soil. phoD was found in 1 archaeal, 13 bacterial and 2 fungal phyla, and phoX in 1 archaeal and 16 bacterial phyla...
October 12, 2016: FEMS Microbiology Ecology
P Maza-Márquez, A González-Martínez, M V Martínez-Toledo, M Fenice, A Lasserrot, J González-López
This study presents an effective technology for the olive processing industry to remediate olive washing water. A 14.5-L enclosed tubular photobioreactor was inoculated with a stable microalgal-bacterial consortium obtained by screening strains well adapted to olive washing water. The capacity of an enclosed tubular photobioreactor to remove toxic compounds was evaluated under photosynthesis conditions and without any external supply of oxygen. The results showed that the dominant green microalgae Scenedesmus obliquus, Chlorella vulgaris and the cyanobacteria Anabaena sp...
October 12, 2016: Environmental Science and Pollution Research International
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