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https://www.readbyqxmd.com/read/28634756/a-high-throughput-targeted-and-non-targeted-method-for-the-analysis-of-microcystins-and-anatoxin-a-using-on-line-solid-phase-extraction-coupled-to-liquid-chromatography-quadrupole-time-of-flight-high-resolution-mass-spectrometry
#1
Xavier Ortiz, Eva Korenkova, Karl J Jobst, Karen A MacPherson, Eric J Reiner
Microcystins are cyclic heptapeptide hepatotoxins produced by cyanobacteria in freshwater. Sample preparation for the analysis of these cyanotoxins in water from algal blooms can take up to several days due to the matrix complexity and the low detection limits required to comply with current legislation. Moreover, there is a large number of unknown microcystins that could potentially exist in the environment resulting from different amino acid substitutions into the microcystin skeletal structure. To tackle these problems, the present study involved the development of a high throughput method based on on-line solid phase extraction coupled to liquid chromatography that could provide quantitative results for 12 microcystin variants (LR, YR, RR, HtyR, HilR, WR, LW, LA, LF, LY, Dha(7)-LR, and Dha(7)-RR) and anatoxin-A in less than 3 h with detection limits between 0...
June 20, 2017: Analytical and Bioanalytical Chemistry
https://www.readbyqxmd.com/read/28634653/assessing-the-combined-toxicity-of-bmaa-and-its-isomers-2-4-dab-and-aeg-in-vitro-using-human-neuroblastoma-cells
#2
Brendan J Main, Kenneth J Rodgers
The non-protein amino acid (NPAA) ß-methylamino-L-alanine (BMAA) is produced by a diverse range of cyanobacteria, diatoms and dinoflagellates, and is present in both aquatic and terrestrial ecosystems globally. Exposure to BMAA has been implicated in the development of neurodegenerative diseases including amyotrophic lateral sclerosis (ALS), Alzheimer's disease (AD) and Parkinson's disease (PD). BMAA is often found in nature along with its structural isomers 2,4-diaminobutyric acid (2,4-DAB) and aminoethylglycine (AEG); however, the toxicity of these NPAAs in combination has not been examined...
June 20, 2017: Neurotoxicity Research
https://www.readbyqxmd.com/read/28634470/the-dark-side-of-the-mushroom-spring-microbial-mat-life-in-the-shadow-of-chlorophototrophs-ii-metabolic-functions-of-abundant-community-members-predicted-from-metagenomic-analyses
#3
Vera Thiel, Michael Hügler, David M Ward, Donald A Bryant
Microbial mat communities in the effluent channels of Octopus and Mushroom Springs within the Lower Geyser Basin of Yellowstone National Park have been extensively characterized. Previous studies have focused on the chlorophototrophic organisms of the phyla Cyanobacteria and Chloroflexi. However, the diversity and metabolic functions of the other portion of the community in the microoxic/anoxic region of the mat are poorly understood. We recently described the diverse but extremely uneven microbial assemblage in the undermat of Mushroom Spring based on 16S rRNA amplicon sequences, which was dominated by Roseiflexus members, filamentous anoxygenic chlorophototrophs...
2017: Frontiers in Microbiology
https://www.readbyqxmd.com/read/28632895/genome-mining-reveals-high-incidence-of-putative-lipopeptide-biosynthesis-nrps-pks-clusters-containing-fatty-acyl-amp-ligase-genes-in-biofilm-forming-cyanobacteria
#4
Tomáš Galica, Pavel Hrouzek, Jan Mareš
Cyanobacterial lipopeptides exhibit antimicrobial and antifungal bioactivities with potential for use in pharmaceutical research. However, due to their haemolytic activity and cytotoxic effects against human cells, they may pose a health issue if produced in substantial amounts in the environment. In bacteria, lipopeptides can be synthesized via several well-evidenced mechanisms. In one of them, fatty acyl-AMP ligase (FAAL) initiates the biosynthesis by activation of a fatty acyl residue. We have performed a bioinformatic survey of the cyanobacterial genomic information available in the public databases for the presence of FAAL-containing non-ribosomal peptide synthetase/polyketide synthetase (NRPS/PKS) biosynthetic clusters, as a genetic basis for lipopeptide biosynthesis...
June 20, 2017: Journal of Phycology
https://www.readbyqxmd.com/read/28631353/microbiome-dynamics-in-early-life-stages-of-the-scleractinian-coral-acropora-gemmifera-in-response-to-elevated-pco2
#5
Guowei Zhou, Lin Cai, Tao Yuan, Renmao Tian, Haoya Tong, Weipeng Zhang, Lei Jiang, Minglan Guo, Sheng Liu, Pei-Yuan Qian, Hui Huang
Reef-building coral is a complex holobiont, harbouring diverse microorganisms that play essential roles in maintaining coral health. However, microbiome development in early life stages of coral remains poorly understood. Here, microbiomes of Acropora gemmifera were analysed during spawning and early developmental stages, and also under different seawater partial pressure of CO2 (pCO2 ) conditions, using amplicon sequencing of 16S rRNA gene for bacteria and archaea and of ITS2 for Symbiodinium. No remarkable microbiome shift was observed in adults before and after spawning...
June 19, 2017: Environmental Microbiology
https://www.readbyqxmd.com/read/28630351/evolutionary-radiation-of-lanthipeptides-in-marine-cyanobacteria
#6
Andres Cubillos-Ruiz, Jessie W Berta-Thompson, Jamie W Becker, Wilfred A van der Donk, Sallie W Chisholm
Lanthipeptides are ribosomally derived peptide secondary metabolites that undergo extensive posttranslational modification. Prochlorosins are a group of lanthipeptides produced by certain strains of the ubiquitous marine picocyanobacteria Prochlorococcus and Synechococcus Unlike other lanthipeptide-producing bacteria, picocyanobacteria use an unprecedented mechanism of substrate promiscuity for the production of numerous and diverse lanthipeptides using a single lanthionine synthetase. Through a cross-scale analysis of prochlorosin biosynthesis genes-from genomes to oceanic populations-we show that marine picocyanobacteria have the collective capacity to encode thousands of different cyclic peptides, few of which would display similar ring topologies...
June 19, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/28628991/bacterial-community-composition-in-rainwater-associated-with-synoptic-weather-in-an-area-downwind-of-the-asian-continent
#7
Wei Hu, Kotaro Murata, Yuka Horikawa, Ayumi Naganuma, Daizhou Zhang
Bacteria are abundant in atmospheric waters and can be disseminated by precipitation to the surface of the Earth, potentially influencing ecosystems, public health and climate. However, data on bacterial communities in rainwater, especially on the association with weather, are very limited. In this study, rainwater was collected at the coastal city Kumamoto, southwestern Japan, in 2015. The bacterial communities in fourteen samples were identified using 16S rRNA sequencing and compared according to the rain types at the synoptic scale, i...
June 13, 2017: Science of the Total Environment
https://www.readbyqxmd.com/read/28624904/the-effect-of-light-on-bacterial-activity-in-a-seaweed-holobiont
#8
Sergio A Coelho-Souza, Stuart R Jenkins, Antonio Casarin, Maria Helena Baeta-Neves, Leonardo T Salgado, Jean R D Guimaraes, Ricardo Coutinho
Holobionts are characterized by the relationship between host and their associated organisms such as the biofilm associated with macroalgae. Considering that light is essential to macroalgae survival, the aim of this study was to verify the effect of light on the heterotrophic activity in biofilms of the brown macroalgae Sargassum furcatum during its growth cycle. Measurements of heterotrophic activity were done under natural light levels at different times during a daily cycle and under an artificial extinction of natural light during the afternoon...
June 17, 2017: Microbial Ecology
https://www.readbyqxmd.com/read/28624734/indirect-influence-of-eutrophication-on-air-water-exchange-fluxes-sinking-fluxes-and-occurrence-of-polycyclic-aromatic-hydrocarbons
#9
Yuqiang Tao, Jing Yu, Guoliang Lei, Bin Xue, Fengju Zhang, Shuchun Yao
How eutrophication affects biogeochemical processes of hydrophobic organic contaminants (HOCs) in aquatic environments is a pending challenge. Although the direct influence of eutrophication on biogeochemical processes of HOCs in waters has been well addressed, the indirect influence of eutrophication on biogeochemical processes of HOCs remains largely unknown. Here we take the large shallow eutrophic Lake Taihu in China and polycyclic aromatic hydrocarbons (PAHs) as examples to provide novel knowledge on the indirect influence of eutrophication on air - water exchange fluxes, sinking fluxes, and occurrence of HOCs...
June 10, 2017: Water Research
https://www.readbyqxmd.com/read/28624729/modis-observations-of-cyanobacterial-risks-in-a-eutrophic-lake-implications-for-long-term-safety-evaluation-in-drinking-water-source
#10
Hongtao Duan, Min Tao, Steven Arthur Loiselle, Wei Zhao, Zhigang Cao, Ronghua Ma, Xiaoxian Tang
The occurrence and related risks from cyanobacterial blooms have increased world-wide over the past 40 years. Information on the abundance and distribution of cyanobacteria is fundamental to support risk assessment and management activities. In the present study, an approach based on Empirical Orthogonal Function (EOF) analysis was used to estimate the concentrations of chlorophyll a (Chla) and the cyanobacterial biomarker pigment phycocyanin (PC) using data from the MODerate resolution Imaging Spectroradiometer (MODIS) in Lake Chaohu (China's fifth largest freshwater lake)...
June 10, 2017: Water Research
https://www.readbyqxmd.com/read/28622287/a-niche-for-cyanobacteria-producing-chlorophyll-f-within-a-microbial-mat
#11
Satoshi Ohkubo, Hideaki Miyashita
Acquisition of additional photosynthetic pigments enables photosynthetic organisms to survive in particular niches. To reveal the ecological significance of chlorophyll (Chl) f, we investigated the distribution of Chl and cyanobacteria within two microbial mats. In a 7-mm-thick microbial mat beneath the running water of the Nakabusa hot spring, Japan, Chl f was only distributed 4.0-6.5 mm below the surface, where the intensity of far-red light (FR) was higher than that of photosynthetically active radiation (PAR)...
June 16, 2017: ISME Journal
https://www.readbyqxmd.com/read/28620737/analysis-of-bmaa-enantiomers-in-cycads-cyanobacteria-and-mammals-in-vivo-formation-and-toxicity-of-d-bmaa
#12
J S Metcalf, Doug Lobner, Sandra Anne Banack, Gregory A Cox, Peter B Nunn, Peter B Wyatt, Paul Alan Cox
Chronic dietary exposure to the cyanobacterial toxin β-N-methylamino-L-alanine (BMAA) triggers neuropathology in non-human primates, providing support for the theory that BMAA causes a fatal neurodegenerative illness among the indigenous Chamorro people of Guam. However, since there are two stereoisomers of BMAA, it is important to know if both can occur in nature, and if so, what role they might play in disease causation. As a first step, we analysed both BMAA enantiomers in cyanobacteria, cycads, and in mammals orally dosed with L-BMAA, to determine if enantiomeric changes could occur in vivo...
June 15, 2017: Amino Acids
https://www.readbyqxmd.com/read/28616951/direct-characterization-of-the-native-structure-and-mechanics-of-cyanobacterial-carboxysomes
#13
Matthew Faulkner, Jorge Rodriguez-Ramos, Gregory F Dykes, Siân V Owen, Selene Casella, Deborah M Simpson, Robert J Beynon, Lu-Ning Liu
Carboxysomes are proteinaceous organelles that play essential roles in enhancing carbon fixation in cyanobacteria and some proteobacteria. These self-assembling organelles encapsulate Ribulose 1,5-bisphosphate carboxylase/oxygenase (Rubisco) and carbonic anhydrase using a protein shell structurally resembling an icosahedral viral capsid. The protein shell serves as a physical barrier to protect enzymes from the cytosol and a selectively permeable membrane to mediate transport of enzyme substrates and products...
June 15, 2017: Nanoscale
https://www.readbyqxmd.com/read/28614737/glucose-triggers-the-cytotoxicity-of-citrobacter-sp-r1-against-microcystis-aeruginosa
#14
Pengfei Sun, Sofia Esquivel-Elizondo, Yuhua Zhao, Yonghong Wu
Algicidal bacteria offer a promising option for killing Microcystis aeruginosa, one notorious cyanobacteria causing harmful algal blooms. In this study, Citrobacter sp. R1 presented high algicidal activity (81.6±2.2%, 72h) against M. aeruginosa when cultured using glucose, while it showed no algicidal activity (0±3.4%) when cultured using wheat bran, suggesting that appropriate carbon source is crucial for algicidal bacteria in killing M. aeruginosa. The underlying algicidal mechanism of strain R1 was explored by studying the effect of different carbon sources (glucose and wheat bran) on its key algicidal gene expression and total protein translation...
June 11, 2017: Science of the Total Environment
https://www.readbyqxmd.com/read/28611747/microbial-community-and-functional-structure-significantly-varied-among-distinct-types-of-paddy-soils-but-responded-differently-along-gradients-of-soil-depth-layers
#15
Ren Bai, Jun-Tao Wang, Ye Deng, Ji-Zheng He, Kai Feng, Li-Mei Zhang
Paddy rice fields occupy broad agricultural area in China and cover diverse soil types. Microbial community in paddy soils is of great interest since many microorganisms are involved in soil functional processes. In the present study, Illumina Mi-Seq sequencing and functional gene array (GeoChip 4.2) techniques were combined to investigate soil microbial communities and functional gene patterns across the three soil types including an Inceptisol (Binhai), an Oxisol (Leizhou), and an Ultisol (Taoyuan) along four profile depths (up to 70 cm in depth) in mesocosm incubation columns...
2017: Frontiers in Microbiology
https://www.readbyqxmd.com/read/28611738/identification-of-cyanobacteria-in-a-eutrophic-coastal-lagoon-on-the-southern-baltic-coast
#16
Martin Albrecht, Thomas Pröschold, Rhena Schumann
Cyanobacteria are found worldwide in various habitats. Members of the picocyanobacteria genera Synechococcus and Prochlorococcus dominate in oligotrophic ocean waters. Other picocyanobacteria dominate in eutrophic fresh or brackish waters. Usually, these are morphologically determined as species of the order Chroococcales/clade B2. The phytoplankton of a shallow, eutrophic brackish lagoon was investigated. Phytoplankton was dominated by Aphanothece-like morphospecies year-round for more than 20 years, along a trophy and salinity gradient...
2017: Frontiers in Microbiology
https://www.readbyqxmd.com/read/28611239/light-harvesting-in-phototrophic-bacteria-structure-and-function
#17
REVIEW
Rafael G Saer, Robert E Blankenship
This review serves as an introduction to the variety of light-harvesting (LH) structures present in phototrophic prokaryotes. It provides an overview of the LH complexes of purple bacteria, green sulfur bacteria (GSB), acidobacteria, filamentous anoxygenic phototrophs (FAP), and cyanobacteria. Bacteria have adapted their LH systems for efficient operation under a multitude of different habitats and light qualities, performing both oxygenic (oxygen-evolving) and anoxygenic (non-oxygen-evolving) photosynthesis...
June 13, 2017: Biochemical Journal
https://www.readbyqxmd.com/read/28609133/carotenoids-biosynthesis-and-cleavage-related-genes-from-bacteria-to-plants
#18
Ming-Hua Liang, Jianhua Zhu, Jian-Guo Jiang
Carotenoids are essential for photosynthesis and photoprotection in photosynthetic organisms and beneficial for human health. Apocarotenoids derived from carotenoid degradation can serve critical functions including hormones, volatiles, and signals. They have been used commercially as food colorants, animal feed supplements, and nutraceuticals for cosmetic and pharmaceutical purposes. This review focuses on the molecular evolution of carotenogenic enzymes and carotenoid cleavage oxygenases (CCOs) from bacteria, fungi, cyanobacteria, algae, and plants...
June 13, 2017: Critical Reviews in Food Science and Nutrition
https://www.readbyqxmd.com/read/28606753/molecular-characterization-of-co2-sequestration-and-assimilation-in-microalgae-and-its-biotechnological-applications
#19
REVIEW
Baojun Zhu, Gu Chen, Xupeng Cao, Dong Wei
Microalgae are renewable feedstock for sustainable biofuel production, cell factory for valuable chemicals and promising in alleviation of greenhouse gas CO2. However, the carbon assimilation capacity is still the bottleneck for higher productivity. Molecular characterization of CO2 sequestration and assimilation in microalgae has advanced in the past few years and are reviewed here. In some cyanobacteria, genes for 2-oxoglytarate dehydrogenase was replaced by four alternative mechanisms to fulfill TCA cycle...
June 1, 2017: Bioresource Technology
https://www.readbyqxmd.com/read/28604867/how-seaweeds-release-the-excess-energy-from-sunlight-to-surrounding-sea-water
#20
Kenichi Koizumi, Makoto Hatakeyama, Mauro Boero, Katsuyuki Nobusada, Hirokazu Hori, Taku Misonou, Shinichiro Nakamura
We report an atomistic insight into the mechanism regulating the energy released by a porphyra-334 molecule, the ubiquitous photosensitive component of marine algae, in a liquid water environment upon an electron excitation. To quantify this rapidly occurring process, we resort to the Fourier analysis of the mass-weighted auto-correlation function, providing evidence for a remarkable dynamic change in the number of hydrogen bonds among water molecules and between the porphyra-334 and its surrounding hydrating water...
June 21, 2017: Physical Chemistry Chemical Physics: PCCP
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